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JOHNSON MATTHEY TECHNOLOGY REVIEW

Johnson Matthey’s international journal of research exploring science and technology in industrial applications

Johnson Matthey Technology Review is published by Johnson Matthey Plc.

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Johnson Matthey’s international journal of research exploring science and technology in industrial applications

Contents Volume 59, Issue 1, January 2015

2 Introduction to Battery Technologies at Johnson Matthey A guest editorial by Martin Green 4 Automotive Lithium-Ion Batteries By Peter Miller 14 Platinum Group Metal-Catalysed Carbonylation as the Basis of Alternative Gas-To-Liquids Processes By Iren Makaryan, Igor Sedov and Valery Savchenko 26 “Nanomaterials for Lithium-Ion Batteries: Fundamentals and Applications” A book review by Sarah Ball 30 “Electrolytes for Lithium and Lithium-Ion Batteries” A book review by Sarah Ball 34 Secondary Lithium-Ion Battery Anodes: From First Commercial Batteries to Recent Research Activities By Nicholas Loefﬂ er, Dominic Bresser, Stefano Passerini and Mark Copley 45 10th International Congress on Membrane and Membrane Processes A conference review by Xavier (Xian-Yang) Quek 52 In the Lab: Development of Carbon Based Electrochemical Sensors for Water Analysis Featuring Julie Macpherson 56 17th International Meeting on Lithium Batteries A conference review by Mario Joost and Sam Alexander 64 Development of Low Temperature Three-Way Catalysts for Future Fuel Efficient Vehicles By Hai-Ying Chen and Hsiao-Lan (Russell) Chang 68 Johnson Matthey Highlights http://dx.doi.org/10.1595/205651315X686723 Johnson Matthey Technol. Rev., 2015, 59, (1), 2–3 JOHNSON MATTHEY TECHNOLOGY REVIEW www.technology.matthey.com

Guest Editorial Introduction to Batteries at Johnson Matthey

It may surprise some readers to see an edition of this generation batteries and operates at two points in the journal dedicated largely to lithium-ion batteries, but value chain for lithium-ion batteries (Figure 1). this is a technology that Johnson Matthey considers Through a combination of in-house R&D and a major new business area for the company. acquisition the company is establishing itself as a Johnson Matthey has been involved in research and signiﬁ cant player in the sector. From an initial position development (R&D) in the battery materials space for in lithium iron phosphate materials, further investments several years and launched its commercial business in the coming years will expand the product range, operations in the sector in 2012. Since then, the working with cell developers to commercialise improved company has made a series of acquisitions to establish and next generation materials. itself both as a global supplier of cathode materials and There are big challenges to deliver the performance of advanced battery systems. Complemented by its required for advanced lithium-ion cells, not just initial lithium-ion battery research group at the Technology performance but durability and long term safety, as well Centres in Sonning Common, UK, and in Singapore, as cost. Good cell design and efﬁ cient manufacture are the Battery Technology business of Johnson Matthey critical elements but the functional materials used are sits within its New Business Division. It represents a also important contributors and big improvements are further expansion of the company’s core strengths still required. We believe that Johnson Matthey’s deep and expertise in chemistry and advanced materials to understanding of functional materials design can be develop new, high technology products. applied to some of these challenges and we think that solving them is a huge opportunity. Johnson Matthey Battery Technologies At the other end of the chain we will continue to work on the design and supply of complex, high performance Johnson Matthey Battery Technologies brings together battery systems for demanding customers in both the company’s activities in lithium-ion and next automotive and non-automotive sectors. In addition to

Cell System OEM Raw materials Cell materials manufacture design customer e.g. precursors e.g. cathodes Engineering, Engineering & e.g. vehicle optimisation & manufacture producers fabrication

Fig. 1. Johnson Matthey Battery Systems’ input into the value chain for lithium-ion batteries

2 © 2015 Johnson Matthey http://dx.doi.org/10.1595/205651315X686723 Johnson Matthey Technol. Rev., 2015, 59, (1) being an attractive growth sector in its own right the The Practical Lithium Air Batteries (PLAB) project battery systems activities help defi ne future materials brings together a range of academic and industrial requirements through providing deep applications partners with complementary skills to work on improved knowledge in the sector. lithium-air battery single cells and assess their Taken together Johnson Matthey’s Battery businesses feasibility in future battery pack and system design, will have three major manufacturing operations in compact air purifi cation approaches and general China, Canada and Poland together with R&D facilities viability for use in automotive applications. Academic in the UK, in Germany and in Singapore. partners Queens University Belfast and Liverpool As well as looking at today’s lithium-ion chemistries University, both in the UK, will work on synthesising Johnson Matthey continues to invest in longer term and characterising the new electrolytes, whilst Johnson research in the sector, covering next generation lithium- Matthey Technology Centre will produce novel cathode ion and also other systems such as metal-air and metal- and anode materials, optimise electrode structures sulfur chemistries. and perform electrochemical testing. The participation of Jaguar Land Rover as an end user and Johnson Research and Development Matthey Battery Systems (formerly Axeon) will provide an applications focused approach and they will perform Examples of collaborative, EU-funded programmes in a paper feasibility study on how high performing lithium- which Johnson Matthey is involved include the Lithium air single cells would be incorporated into automotive Sulfur Superbattery Exploitating Nanotechnology systems in the future. The fi nal output will assess the (LISSEN) project. This project is aimed at the feasibility for lithium air battery systems to achieve a identifi cation and development of nanostructured 400 Wh kg–1 power density. electrode and electrolyte materials to promote the MARS-EV aims to overcome the ageing phenomenon practical implementation of the very high energy in Li-ion cells by focusing on the development of high- lithium-sulfur battery. It is expected that this battery energy electrode materials (250 Wh kg–1 at cell level) will offer an energy density at least three times higher via sustainable scaled-up synthesis and safe electrolyte than that available from the present lithium battery systems with improved cycle life (> 3000 cycles at 100% technology, a comparatively long cycle life, a much depth of discharge (DOD)). Through industrial prototype lower cost (replacement of cobalt-based with a cell assembly and testing coupled with modelling sulfur-based cathode) and a high degree of safety MARS-EV will improve the understanding of the ageing (no use of lithium metal). The project will benefi t behaviour at the electrode and system levels. Finally, it from the support of a laboratory expert in battery will address a full life cycle assessment of the developed modelling, large research laboratories having modern technology. MARS-EV brings together partners with battery production facilities and chemical and battery complementary skills and expertise, including industry manufacturing industry partners. and covering the complete chain from active materials Stable Interfaces for Rechargeable Batteries suppliers to cell and battery manufacturers, thus (SIRBATT) is a multisite collaborative project consisting ensuring that developments in MARS-EV will directly of 12 full partners from the European area (six improve European battery production capacities. universities, one research institute and fi ve industrial Johnson Matthey is excited to be involved in these partners). Collaboration with leading battery research and many other projects in the fi eld of lithium battery groups in the USA and Japan is also considered. research. We hope that readers will enjoy the articles SIRBATT will develop microsensors to monitor internal about lithium batteries in this issue, and look out temperature and pressure of lithium cells in order to for future articles and reviews on this topic in future maintain optimum operating conditions to allow long-life issues. times that can be scaled for use in grid scale batteries. MARTIN GREEN The scientifi c aim of SIRBATT is a radical improvement Director, Battery Technologies in the fundamental understanding of the structure Johnson Matthey Plc, 5th Floor, 25 Farringdon St, and reactions occurring at lithium battery electrode/ London, EC4A 4AB, UK electrolyte interfaces. Email: [email protected]

JOHNSON MATTHEY TECHNOLOGY REVIEW www.technology.matthey.com

Automotive Lithium-Ion Batteries State of the art and future developments in lithium-ion battery packs for passenger car applications

By Peter Miller 1. Introduction Johnson Matthey Battery Systems, Orchard Road, Royston, Hertfordshire, SG8 5HE, UK Lithium-ion cells (Figure 1) (1), in their most common form, consist of a graphite anode, a lithium metal Email: [email protected] oxide cathode and an electrolyte of a lithium salt and an organic solvent. Lithium is a good choice for an electrochemical cell due to its large standard electrode Recently lithium-ion batteries have started to be used potential (–3.04 V) resulting in a high operating voltage in a number of automotive passenger car applications. (which helps both power and energy) and the fact that This paper will review these applications and compare it is the metal with the lowest density (which reduces the requirements of the applications with the capabilities weight). of the lithium-ion chemistries that are actually being The construction of a typical cylindrical cell is shown used. The gaps between these requirements and in Figure 2, while Figure 3 shows a typical pouch capabilities will be highlighted and future developments cell. Such cells provide a relatively light and small that may be able to fill these gaps will be discussed. source of energy and are now manufactured in very It is concluded that while improvements to the lithium- large quantities (>1 billion cells per year) (2). In an ion cell chemistry will help reduce the weight of battery automotive application a lithium-ion battery consists of packs for electric vehicle applications the largest weight tens to thousands of individual cells packaged together gains will come from the pack design. to provide the required voltage, power and energy.

– e e– 3 V

LixC6 Graphite LiCoO2 Li+ conducting electrolyte Li+ charge e– e–

Li+ discharge

Fig. 1. Diagrammatic view of a lithium-ion cell (1)

+ve/–ve Terminals +ve/–ve Terminals and safety vent Metal case

Anode

Separator

Cathode Metallised foil pouch Anode Separator Cathode Fig. 2. Internal construction of a typical cylindrical cell (1) Fig. 3. Internal construction of a typical pouch cell (1)

Individual cells are normally mounted into a number of applications for this reason. modules, which are then assembled into the complete The structure of this paper is as follows. In Section 2 battery pack as shown in Figure 4. a number of automotive passenger car applications Many countries have now put in place binding carbon for lithium-ion batteries are presented and their dioxide emissions targets for cars, for example in key requirements listed. Section 3 will give a brief

Europe the requirements are for fleet average CO2 overview of the capabilities of a number of lithium-ion emissions of 130 g km–1 by 2015 and 95 g km–1 by chemistries currently in use for automotive applications 2021 (3). It will be shown in Section 2 of this paper and Section 4 will compare the requirements (from that by using a (lithium-ion) battery it is possible to Section 2) with the capabilities listed in Section 3. significantly reduce a car’s CO2 emissions. More Section 5 will look at future developments, while lithium-ion batteries are now being used in automotive Section 6 will offer some conclusions.

Fig. 4. CAD of disassembled battery module, assembled module and whole battery package (1)

2. Automotive Applications for Lithium-ion other options are used including ultracapacitors and Batteries lithium-ion which was first used in 2002 on the Toyota Vitz CVT, which to the author’s knowledge was the first There are a range of applications for batteries in production car to use a lithium-ion battery pack. passenger cars (4). The ones that will be considered Many idle stop systems also intelligently control the here were selected either because they already use vehicle’s alternator, for example using it to generate lithium-ion batteries or because they could potentially maximum power when the vehicle is slowing down do so in the future. Note that there are a number of (giving a limited degree of regenerative braking standard automotive requirements that all lithium-ion capability) and these systems are frequently called batteries used in cars need to meet: these include life micro hybrids. (8–15 years are typical requirements), temperature range (–40°C to at least +60°C, ideally 80°C) and 2.3 Mild Hybrid vibration resistance (at least 4.5 root-mean-square- In a mild hybrid the electrical energy is used to acceleration (grms)) (5). Each application will now be supplement the energy from the combustion engine. briefly described. By use of a suitable control system to decide how to mix these two energy sources significant savings 2.1 Starting Lighting Ignition in fuel (typically 10%–15%, but up to 30% has been Starting lighting ignition (SLI) is the ‘car battery’ that shown in some demonstrator vehicles) can be obtained has been in almost every car for the last 100 years. for a moderate increase in system cost (4). Batteries Commonly this is called a ‘12 V battery’, but its normal for this application only require a small amount of voltage (while in use in the car and being charged power and energy. Most batteries for this application by the alternator) is nearer 14 V. In almost all current at present are nickel metal hydride (NiMH), with production cars this is a lead-acid battery, but there lithium-ion first used in 2010 for the Mercedes S400 are a few cars now that use a lithium-ion battery either hybrid. As this paper is focused on lithium-ion batteries, as standard (for example, the McLaren P1) or as an NiMH batteries (which is an older technology that option (for example, some Porsche models). In the offers lower energy density than lithium-ion) will not be Porsche Boxster Spyder the lithium-ion battery is a covered in further detail here. US$1700 option and has the same form factor and Note that the number of mild hybrids produced is soon mounting points as the standard lead-acid battery, but expected to significantly increase due to the use of 48V weighs only 6 kg which is 10 kg lighter than the lead- systems within a vehicle. This shift is driven by the acid option. It should be noted that Porsche supply a European 2020 fleet CO2 requirements (3). The use conventional lead-acid battery as well as the lithium-ion of 48 V was originally proposed in 2011 by Audi, BMW, one for use in cold temperatures where the lithium-ion Daimler, Porsche and Volkswagen (6) and resulted in pack may not be able to provide enough power to crank the LV 148 standard (7). Audi recently stated that they the engine (see Section 3). expect such systems to be in production within the next two years (8) and it is expected that all 48 V systems 2.2 Idle Stop will be based on lithium-ion batteries. This is a system that is now fitted to the majority of It should also be noted that most fuel cell vehicles will European vehicles which switches the combustion also be hybrids (4). For example, Toyota has recently engine off whenever the vehicle is stationary, restarting announced that it will start sales of a fuel cell sedan it when you go to drive off (4). It offers around a 5% in early 2015 and this is a mild hybrid using a small saving in fuel economy at an estimated system cost battery to supplement the fuel cell and increase the of around US$350 (4), which makes it an attractive vehicle’s overall efficiency (9). solution for original equipment manufacturers (OEMs) 2.4 Full Hybrid looking to meet the European 2015 CO2 limits. The requirements for a battery for this application are In a full hybrid, the approach is similar to that of the mild very similar to those of an SLI battery, but the more hybrid, but the electrical power and stored energy are frequent starting and stopping of the engine requires now high enough to power the car purely from electrical a longer cycle life. The vast majority of batteries for energy. The battery energy available normally limits the this application are still lead-acid, but a number of range in this mode to a few kilometres. An example of

6 © 2015 Johnson Matthey http://dx.doi.org/10.1595/205651315X685445 Johnson Matthey Technol. Rev., 2015, 59, (1) this sort of vehicle is the Toyota Prius (although this vehicle to the ‘standard’ Toyota Prius which is a full currently uses a NiMH battery pack), which is by far hybrid vehicle) are more affordable options. All use the most successful hybrid vehicle sold so far. It has lithium-ion batteries. The power required from the around a 1 mile range in electric vehicle (EV) mode. battery is similar to that required in a full hybrid, but Fuel consumption savings in a full hybrid are typically more energy needs to be stored to make the effort to 30%–40%, for example on the 2014 Toyota Yaris the recharge from the grid worthwhile. 1.33 gasoline (98 bhp / 73 kW) produces 114 g km–1 of For the purposes of this paper a range extended

CO2 emissions, while the hybrid (also 98 bhp / 73 kW) electric vehicle (REEV) will be considered a type achieves 75 g km–1, a 34% reduction. of PHEV. Batteries for this application must provide more power (to act as the sole source of power in the vehicle) and 2.6 Electric Vehicle more energy than for a mild hybrid application. Most An EV has the battery as its only source of energy. An applications (by volume) are still NiMH, but a significant example of this type of vehicle is the Nissan Leaf. An number of vehicles are now lithium-ion based, including EV has zero tailpipe emissions, although the Leaf is –1 the BMW Active Hybrid 3 which can drive for 2.5 miles estimated to emit 66.83 g km CO2 in the UK based at up to 37 mph on electric power alone. Hybrid on the CO2 produced by the mains electricity used to electric vehicle (HEV) is a phrase that has been used refuel it. The power required from an EV battery is the to describe mild hybrid and a full hybrid vehicles and same as for a PHEV (both need to be able to power has even been applied to some vehicles with little more the car), but in an EV as much energy as practical is than idle-stop systems (micro hybrids). fitted to give a reasonable range (typically ~100 miles). This large energy requirement explains the ‘low cost’ 2.5 Plug in Hybrid Electric Vehicle requirement (in $/kWh terms) for EVs in Table I, as the The plug in hybrid electric vehicle (PHEV) could be battery cost needs to be compared with a conventional considered to be a full hybrid with the ability to charge fuel tank (~€100 or ~US$130). the battery from the grid. The vehicle is designed to All of the applications listed above are summarised in initially preferentially use the electrical energy from Table I. The typical properties and requirements of the its last charge until this is depleted, at which time it battery technology for each application are shown.The behaves like a full hybrid vehicle. Thus the energy power and energy data in Table I can also be viewed obtained by charging from the grid replaces some as a chart, as shown in Figure 5. energy that would have been required from the liquid fuel (gasoline or diesel), further lowering fuel 3. Lithium-ion Chemistries consumption (and hence tailpipe CO2 emissions). The VW XL1 is a PHEV that offers 313 mpg and 24 g km–1 Lithium-ion cells, in their most common form, consist of of CO2, but the Vauxhall Ampera (GM Volt) and Toyota a graphite anode and a lithium metal oxide cathode and Prius PHEV (note the Toyota Prius PHEV is a different an electrolyte of a lithium salt and an organic solvent.

Table I Typical Passenger Car Applications for Lithium-ion Batteries Commonest Typical Typical Power Typical Special Application battery type voltage(s), V levels, kW energy, kWh requirements today

SLI 14 3 0.7 Lead-acid Cranking at cold

Idle stop 14 3 0.7 Lead-acid Cranking at cold

Mild hybrid 48–200 10–30 0.3 NiMH Long cycle life

Full Hybrid 300–600 60 1–2.5 NiMH Long cycle life

PHEV 300–600 60 4–10 Li-ion Long cycle life

EV 300–600 60 15+ Li-ion Low cost

20 EV 15

10 PHEV

Energy, kWh Energy, 5 SLI/idle stop Mild hybrid Full hybrid 0 0 10 20 30 40 50 60 70 Power, kW Fig. 5. Power and energy requirements for different passenger vehicle battery applications

While the basic format remains constant for all lithium- in Table III below. Note that price has not been included ion cells the detailed chemistry (i.e. cathode and/or in this table as all the ranges effectively overlap, with anode) can be changed, altering the properties of the the exception of the more expensive titanate containing cell. It is not the aim of this paper to give a detailed system. explanation of the manufacture of the various cells or While all these cell chemistries have been used in their chemistries as this is well covered elsewhere (see passenger vehicles and hence can be made adequately for example (1, 2, 10)). safe, the temperature at which thermal runaway starts The main lithium-ion chemistries used in automotive is used here to illustrate the differences between the applications are summarised in Table II (1). In all cases chemistries – the higher this temperature the safer the the anode is graphite apart from the sixth entry in which chemistry is considered to be. Life is given in Table II in the anode is a titanate. terms of cycle life, while the ranking in Table III can be This table can be summarised in terms of key considered to also include calendar life. parameters that are required for commercial application Note that the chemistry that provides the best of these battery technologies in passenger vehicles, as power (lithium iron phosphate (LiFePO4)) is the

Table II Summary of the Main Lithium-ion Variants

Temperature Cell level Cell level Safety Durability Price range in energy energy Power thermal Potential, cycle life, estimate, ambient density, density, C-rate runaway V 100% DoD US$ Wh–1 conditions, Wh kg–1 Wh l–1 onset, °C °C

LiCoO2 170–185 450–490 500 0.31–0.46 1 C 170 3.6 –20 to 60

LiFePO 5 C cont. 4 90–125 130–300 2000 0.3–0.6 270 3.2 –20 to 60 (EV/PHEV) 10 C pulse LiFePO 30 C cont. 4 80–108 200–240 2000 0.4–1.0 270 3.2 –20 to 60 (HEV) 50 C pulse 20 C cont. NCM (HEV) 150 270–290 1500 0.5–0.9 215 3.7 –20 to 60 40 C pulse NCM (EV/ 1 C cont. 155–190 330–365 1500 0.5–0.9 215 3.7 –20 to 60 PHEV) 5 C pulse Titanate vs. 10 C cont. Not 65–100 118–200 12,000 1–1.7 2.5 –50 to 75 NCM/LMO 20 C pulse susceptible Manganese 3–5 C spinel (EV/ 90–110 280 >1000 0.45–0.55 255 3.8 –20 to 50 cont. PHEV)

Table III Key Parameters of Lithium-ion Chemistries

Parameter Highest performing chemistry(s) Lowest performing chemistry

Safety Titanate, LiFePO4 LiCoO2

Power LiFePO4 LiCoO2

Energy LiCoO2, NCM LiFePO4

Life Titanate, LiFePO4 LiCoO2 worst for energy. Both power and energy need to be are likely to be the best fit to the application from a considered when selecting candidate chemistries power and energy viewpoint, as chemistries with for applications and this idea will be explored further lines a long way away will have a significant excess in Section 4. of power or energy beyond the requirements. This The last parameter for consideration is low temperature is likely to make them a more expensive solution (in performance and this is best shown by a graph (Figure 6 terms of cost, weight and volume) than solutions with which is based on data from (11) with lithium-ion added lines close to the dot. by the present author based on measurements of an It can be seen that there are good matches for the automotive LiFePO4 lithium-ion cell). mild and full hybrid and PHEV, but not a particularly This graph shows that valve-regulated lead-acid good match for the EV requirements. (VRLA) battery technology offers significantly higher This means that companies offering a range of power at cold temperatures and so is better suited for different types of hybrid vehicle will normally need to cold cranking applications (which require the ability to select multiple chemistries (which also normally means crank the engine at –40°C). multiple suppliers). For example BMW uses A123

LiFePO4 cells in its hybrids, while it uses Samsung SDI 4. Lithium-ion for Various Applications (nickel-manganese-cobalt (NMC)) for its EV and PHEV vehicles (12), both of which can be seen to be sensible One way to view the suitability of lithium-ion for choices based on Figure 3. However there is no various applications is to compare the power:energy industry consensus, for example while BMW selected ratio for the cells vs. the applications as shown in NMC for its EVs, Honda uses a titanate chemistry in Figure 7. Here the yellow lines show the power:energy its Fit EV and Renault uses spinel lithium manganese ratios for the various chemistries (from Table II), oxide (LMO) in the ZOE EV (13). while the dots show the requirements for each of the It should be noted that while lithium-ion batteries are in applications (Figure 5). The lines closest to the dots use in production cars, low temperature operation (see

1800 1600 1400

–1 1200 1000 VRLA (W kg–1) (11) 800 NiMH (W kg–1) (11) 600 Power, W kg Power, –1 400 Li-ion (W kg ) 200 0 –40 –20 0 20 40 60 Temperature, ºC Fig. 6. Low temperature performance of selected battery chemistries

LiCoO2 20 EV Spinel 15 NCM-EV

Energy, kWh Energy, PHEV LiFePO4-EV 5 Titanate NCM-HEV SLI/idle stop Mild hybrid Full hybrid

0 LiFePO4-HEV 0 10 20 30 40 50 60 70 Power, kW Fig. 7. Power and energy and capabilities of various chemistries

Section 3), life (especially calendar life), temperature thousands of these cells need to be packaged in the range, safety and cost are all areas that ideally need car together with thermal management and electronic to be improved and these challenges still remain after control equipment. A typical automotive battery pack many years of research and development (10). Some today achieves 82 Wh kg–1 (for example, the Nissan progress has been made, for example battery packs Leaf) which is considerably lower than that achievable have improved from 80 Wh kg–1 in the Mitsubishi iMiEV from the cells alone. (launched in 2009) and Nissan Leaf (launched in 2010) Recently prototype battery packs have been to 97 Wh kg–1 in the new Kia Soul EV (launched in May developed with significantly higher energy density. For 2014) (14) which is a 4% per year average (compound) example the SmartBatt programme (17) has recently improvement. This is partly due to the automotive demonstrated an EV battery pack with 148 Wh kg–1 industry’s long timescales (five or more years from part while meeting all other automotive requirements, this selection to volume production is common), but also pack was shown as CAD in Figure 4 and the assembled due to the need for improvements without adversely pack is shown in Figure 8. This was achieved by impacting other parameters. combining 1408 relatively high energy lithium-ion cells (each of 181 Wh kg–1) with innovative materials (including 5. Future Developments an aluminium hybrid foam sandwich material) and state of the art engineering (including a large number of Much research is ongoing into lithium-ion batteries. The crash test simulations to optimise the design). review of lithium batteries (2) dates from 2009 but it is Table IV gives the weight breakdown of the SmartBatt still a useful overview and many of the research topics pack. The 85% gain in energy per unit weight obtained it discusses have yet to make it into volume automotive by the SmartBatt pack far exceeds the long term applications. A theoretical model created at Rice projections of a 30% improvement in energy per unit University and Lawrence Livermore National laboratory weight from lithium-ion chemistry improvements and which predicts how carbon components will perform as together they suggest that a 100% gain in energy per electrodes (15) also has the potential to significantly unit weight (to around 160 Wh kg–1) may be possible at benefit future lithium-ion cell developments. the pack level for EV packs. A recent overview which focuses on energy and cost (and is so most relevant to EV applications) (16) 6. Conclusions suggests that lithium-ion chemistries will improve by probably no more than 30% in terms of energy per unit This paper has shown the range of applications for weight and proposes a range of potential replacement automotive batteries and summarised the different chemistries. However, it should be remembered that requirements for each. This has shown that while an automotive battery pack is much more than just the lithium-ion based battery packs could be used in all chemistry, as the cells themselves have to be packaged the major passenger car battery applications, they using a pouch or can and then hundreds or possibly are best suited to use in PHEV and EV applications

Fig. 8. SmartBatt battery pack

Acknowledgments Table IV SmartBatt Weight Breakdown

Component Mass, kg Fraction, % The author wishes to thank the anonymous referees Housing 8.5 5.5 and the editor for their constructive comments as well Module without as Johnson Matthey for permission to publish this 16.6 10.7 cells paper. Cells 125.3 80.6 Electrical References 2.1 1.4 components 1. “Johnson Matthey Battery Systems: Our Guide to Electrical Batteries”, 2nd Edn., Johnson Matthey Plc, Dundee, 2.9 1.9 connections UK, 2012 TOTAL 155.4 – 2. B. Scrosati and J. Garche, J. Power Sources, 2010, 195, (9), 2419 3. ‘Setting Emission Performance Standards for and are least suited to SLI applications. Even for the New Passenger Cars as Part of the Community’s applications where lithium-ion is being used, it has Integrated Approach to Reduce CO2 Emissions from been shown that different vehicle OEMs have selected Light-Duty Vehicles’, Regulation (EC) No 443/2009 of different chemistries for the same application based on the European Parliament and of the Council of 23 April different interpretations of the trade-offs between the 2009, Official J. Eur. Union, L 140/1, 5th June, 2009 chemistries’ performance and the requirements of the 4. P. Miller, IEEJ Trans. Ind. Appl., 2008, 128, (7), 880 specific application. 5. P. Miller, T. Dobedoe, G. Duncan, T. Pike, D. Sharred It has been stated that new lithium-ion chemistries and P. Smout, ‘Surge Transport and its Role in offer limited potential for improvement (~30% in terms Technology Transfer of Environmental Awareness in –1 of Wh kg ) which has resulted in significant research the Transport Sector’, IEE Seminar on Automotive in non lithium-ion based chemistries which offer the Electronic Standards; Are They?, IET London, Savoy promise of significantly higher gains (16). However it Place, UK, 1999, Ref. No. 1999/206, pp. 4/1–4/8 is shown here that, especially for EV battery packs, 6. C. Hammerschmidt, ‘German Carmakers Agree on major weight gains can come from the overall design 48V On-board Supply, Charging Plug’, Automotive EE of the battery pack and these together with better Times Europe, 16th June, 2011, 222901632 chemistries suggest that a doubling of the energy 7. M. Kuypers, ‘Application of 48 Volt for Mild Hybrid per unit weight for EV battery packs is possible in the Vehicles and High Power Loads’, SAE Paper 2014- relatively near future. 01-1790

8. C. Hammerschmidt, ‘Audi Makes the Leap to 48V 13. C. Garnier, ‘Renault ZE: Path Toward EV Battery Supply’, Automotive EE Times Europe, 25th August, Production’, CAPIRE Workshop, Brussels, Belgium, 2014, 222903784 10th April, 2013 9. S. Bickerstaffe, ‘Elemental Decision’, Automotive 14. ‘Bosch Set to Double Battery Energy Density’, Engineer, 1st January, 2014, pp. 33–34 Automotive Engineer, 2014, 39, (2), 5 10. A. Jossen, ‘Overview on Current Status of Lithium-ion 15 Y. Liu, Y. M. Wang, B. I. Yakobson and B. C. Wood, Batteries’, Second International Renewable Energy Phys. Rev. Lett., 2014, 113, 028304 Storage Conference (IRES II), Bonn, Germany, 19th– 16. R. Van Noorden, Nature, 2014, 507, (7490), 26 21st November, 2007 17. H. Kapeller, ‘SmartBatt: Smart and Safe Integration of 11. M. J. Weighall, J. Power Sources, 2003, 116, (1–2), 151 Batteries in Electric Vehicles’, The 27th International 12. P. Buckley, ‘Samsung SDI Batteries to Drive Future Electric Vehicle Symposium (EVS27), Barcelona, BMW EVs’, EE Times Europe, 15th July, 2014 Spain, 17th–20th November, 2013

The Author

In December 2013 Dr Peter Miller took up the role of Chief Electronics Technologist at Johnson Matthey Battery Systems. Prior to this he was the Director, Electrical/Electronic Engineering at Ricardo and until 2001 he was the European Director of Technology at Motorola Automotive/ Industrial Electronics Group. His primary interests relate to the design, control and use of lithium- ion batteries. Dr Miller is the author of a large number papers and patents. He holds a BSc and PhD from Hull University, UK, is a Chartered Engineer, a fellow of the Institute of Engineering and Technology (IET) and a member of the Institute of Electrical and Electronics Engineers (IEEE) and the Association of Computing Machinery (ACM).

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Platinum Group Metal-Catalysed Carbonylation as the Basis of Alternative Gas-To-Liquids Processes

Conversion of stranded natural and associated petroleum gases to marketable products

By Iren Makaryan,⃰ Igor Sedov and and petrochemical products (for example methanol, Valery Savchenko lubricants and waxes) from hydrocarbon gases have The Institute of Problems of Chemical Physics of the been of interest for the past three decades. This is at Russian Academy of Sciences, Academician Semenov least partly driven by a desire to diversify the utilisation avenue 1, Chernogolovka, Moscow Region, of large or stranded gas reserves by gas conversion 142432, Russia into marketable products with high added value. GTL today is largely dominated by Fischer-Tropsch ⃰ Email: [email protected] (FT) synthesis converting synthesis gas into synthetic fuels for the transport fuel market. Manufacturing GTL fuels is extremely expensive: conventional FT GTL Traditional Fischer-Tropsh synthesis for the conversion technologies consist of three steps (1): (a) production of gas into liquids for fuels and chemicals is uneconomic of synthesis gas or syngas (carbon monoxide and for many stranded natural and remote gas sources. This hydrogen) by oxidation of high purity natural gas or review presents platinum group metal (pgm)-catalysed any methane-rich feedstock in the presence of nickel- carbonylation as the basis of a new generation of based catalysts (this step is the most energy intensive alternative GTL processes to produce petrochemical and comprises more than 50% of the total GTL capital products from hydrocarbon gases. The pgm route cost); (b) FT synthesis – the conversion of syngas in may allow monetisation of stranded natural and the presence of cobalt or iron catalysts to produce associated petroleum gases by converting them into a mixture of hydrocarbons in the form of a synthetic marketable products with high added value, including crude oil (syncrude) (this step consumes ≥25% of for example acetic acid, methyl acetate, ethylidene the GTL capital investment); and (c) hydrocracking diacetate, propanal, methyl propanoate, vinyl acetate, and hydroisomerisation of the synthesised syncrude oligoketones and oligoesters. using precious metal catalysts and syncrude reﬁ ning processes to give marketable products (this step 1. Introduction comprises 15% to 25% of the total capital cost). Unfortunately, today the established processes for 1.1 In Search of Potential New Routes for Gas- natural gas transformation into syngas and consequent to-Liquids FT synthesis require large investments which are As global energy demand and crude oil prices rise, prohibitive for the exploitation of small and stranded alternative production routes for hydrocarbons natural gas reservoirs which make up approximately and petrochemicals are becoming more and more one third of the world’s natural gas reserves. economically and ecologically attractive. Thus, gas- Various attempts are being undertaken by many to-liquids (GTL) processes intended for the production researchers worldwide to avoid the costly production of synthetic liquid fuels as well as other chemical of syngas required by a conventional GTL route

(hydrocarbon gas  syngas → FT → GTL products). may lead to formation of olefi ns (6, 7) which can also For example, scientists working on the European Union be used in a number of reactions. Methanol and olefi ns (EU)-funded project “Innovative Catalytic Technologies produced via this method may potentially be involved and Materials for Next Gas to Liquid Processes” (NEXT- in carbonylation or oligomerisation reactions in the GTL) are addressing the main cost and technical presence of catalysts, giving a wide assortment of challenges associated with conventional GTL processes marketable petrochemicals. (2). They are exploring unconventional novel routes for At present a number of well-known carbonylation catalytic syngas formation, including H2 separation by processes are used industrially for large scale membrane. They are also investigating direct catalytic production. The most effective carbonylation catalysts conversion (without the syngas intermediary) of are based on platinum group metals (pgms) such as methane to methanol/dimethyl ether (DME). rhodium, iridium and palladium. The aim of this article Methanol is an important product of GTL technologies. is to review and discuss pgm-catalysed carbonylation Therefore special attention is paid to the second (in as the basis of a new generation of alternative GTL scale of production) route of GTL performance that processes. For the purposes of this article, the term leads to methanol (gas-to-methanol (GTM) process): ‘carbonylation’ will refer to all reactions that include hydrocarbon gas → syngas → methanol. The Nobel CO additions to various substrates. The latter may be Prize Winner George Olah proposed the use of methanol, ethene, ethanol, formaldehyde and certain methanol as a basic feedstock not only for the chemical other substrates formed during the direct non-catalytic industry but also for the whole power industry in the partial oxidation of hydrocarbon gases. near future (3). Methanol is already a key component of various process fl ow-sheets allowing a broad range of 2. Platinum Group Metal Carbonylation Catalysts technologies to be used for manufacturing high value- added products. As a rule pgm catalysts in carbonylation processes Another EU project, “Oxidative Coupling of Methane are metal complexes with various organic heteroatom Followed by Oligomerisation to Liquids” (OCMOL), was ligands providing selectivity to the required product. aimed at developing a new liquefaction route adapted Sometimes relatively cheap zeolite catalysts and to the exploitation of small gas reservoirs. The OCMOL catalysts based on late transition metals are also used process was based on oxidative coupling of methane in carbonylation. However, such catalysts are less into ethene followed by subsequent oligomerisation of active in comparison with pgm catalysts and therefore ethene to linear α-olefi ns and synthetic fuels including they cannot be effectively used for the carbonylation gasoline and diesel (4). The OCMOL route aimed of mixtures with low substrate content (methanol, to develop a process with economic operation at ethene). Such mixtures are known to be formed during capacities of 100 kT year–1 and more uniform pressures the partial oxidation of natural hydrocarbon gases. with low if not zero CO2 emission. The pgms are used to catalyse many reactions Among the attempts to develop alternative GTL involving CO, H2 and even molecular nitrogen (8). processes a direct non-catalytic partial oxidation of In general, pgm catalysts are active under milder hydrocarbon gases is of great interest. A new route to conditions and show much higher selectivity compared convert hydrocarbon gas → methanol without the step of to other metals. The pgms have many other key syngas production has been developed at the institutes characteristics and are widely applied in industrial of the Russian Academy of Sciences (5). Depending catalysis, despite their high prices (Table I). on reaction conditions, the oxidative conversion of Previous research at the Institute of Problems of hydrocarbon gases at temperatures of 700°C–750°C Chemical Physics of the Russian Academy of Sciences

Table I Johnson Matthey Base Pricesa (9)

Platinum Group Metal Pt Pd Rh Ir Ru

US$ per oz 1264.69 782.87 1229.31 583.30 58.96 a Month average for all time zones, October 2014

(IPCP RAS) includes the development of catalysts methanol) due to the catalytic mechanism proceeding based on pgms (Pd, Pt, Rh, Ir). These catalysts were on Rh active species. This mechanism may be achieved intended for a number of processes, particularly liquid- when the catalyst is promoted by iodide ions because phase hydrogenation and dehydrodechlorination of methanol itself cannot participate in the basic catalytic organic compounds (10, 11), activation of C–H bonds cycle (Figure 1). (12) and copolymerisation of ethene and CO (13). The selectivity of the process is about 85% to CO. The low selectivity is caused primarily by the occurrence of 3. Examples of Platinum Group Metal Catalysed the water gas shift reaction (WGSR), Equation (ii): Conversion of Oxidation Products CO + H2O → CO2 + H2 (ii) Possible products of oxidative conversion of Because this reaction is also catalysed by Rh hydrocarbon gases, including methanol, ethene and complexes, it cannot be avoided by changing the CO, may undergo various reactions to form products operating conditions. Catalysts based on Ir complexes which are in high demand. There are currently a range do not have this shortcoming. of oxidative conversion processes at different stages of The effect of hydrogen (syngas) on methanol commercialisation. The most promising for alternative carbonylation has also been investigated (17, 18). GTL processes are addition reactions of CO to low It was shown that the availability of hydrogen cannot molecular weight substrates, such as carbonylation of prevent the carbonylation of methanol to acetic acid methanol to acetic acid and methyl acetate; production and methyl acetate. of ethylidene diacetate; hydroformylation of ethene to In 1983 Eastman Chemical developed a process of propanal; formation of methyl propanoate during ethene acetic anhydride production by Rh-catalysed iodide- methoxycarbonylation and vinyl acetate by reaction promoted carbonylation of methyl acetate, with a plant of ethene with acetic acid; and the cooligimerisation capacity of 320,000 tons per year (15, 19). Production of of ethene and CO with formation of oligoketones and methyl acetate is performed using standard acetic acid oligoesters. production technology supplemented by esteriﬁ cation of excess methanol under reactive distillation conditions. 3.1 Production of Acetic Acid from Methanol Another option to produce acetic acid via methanol and Carbon Monoxide carbonylation is the CativaTM process developed by The carbonylation of methanol to acetic acid is one BP Chemicals in the early 1990s. This process applies of the major commercialised processes using CO, an Ir-based catalyst and a ruthenium promoter. The Equation (i): technology was commercialised in 1995. The catalytic cycle of methanol carbonylation includes Ir-containing CH OH + CO → CH COOH (i) 3 3 active species. In contrast to the Monsanto process, the The process was described by BASF in 1913 and oxidative addition of methyl iodide to Ir-based catalysts was modiﬁ ed in 1941 to use late transition metal proceeds 150 times faster than for Rh catalysts (20). carbonyl complexes in place of transition metal salts. The selectivity to acetic acid may exceed 99% because Co-catalysed carbonylation was initially commercialised the Ir catalyst prevents the formation of propanoic acid by BASF in 1963. The use of Co-based catalysts as a side product. required extremely harsh process conditions (~250°C, The production of acetic acid by carbonylation of 600 bar) with an acetic acid yield up to 90% based on methanol is considered the most economical of all methanol and up to 70% based on CO (14). commercial methods (oxidation of acetaldehyde and

In the 1960s Monsanto developed an improved low oxidation of C4–C7 hydrocarbons). All new plants under pressure method for methanol carbonylation using construction based on this technology have a capacity an iodide-promoted rhodium complex catalyst with of about 0.5 million tons acetic acid per year for each much higher catalytic activity and selectivity, allowing plant. The capital cost of such plants is estimated at for milder reaction conditions (~175°C, 30 bar) (15). US$500 million each. The ﬁ rst plant based on this technology was put into The global acetic acid market was valued at operation in Texas City, USA, in 1970. This process US$6 billion in 2011 and is expected to reach US$10 billion has since become used in all industrialised countries. by 2018, growing at an annual growth rate of 9.3% over the The achieved selectivity is more than 99% (based on forecast period from 2012 to 2018 (21). Global demand

– I CO Rh I CO

O H2O H3C I – H3C I – I I CO I I CO Rh Rh CH3 I CO I C CO O O H3 HI H3C OH H3C OH

CO – I I CO Rh CH I 3

Fig. 1. Catalytic cycle for rhodium-complex-catalysed methanol carbonylation (Monsanto) (16)

for acetic acid has been steadily increasing over the These syntheses were fi rst proposed by Halcon in last ten years (10.25 million tons in 2011 compared the 1980s. It was found that they are 30%–40% more to 6.11 million tons in 2000) and is estimated to reach effi cient than traditional reaction routes. It has recently 15.5 million tons by 2020. Demand in advanced been shown (26) that the best feedstock for production countries has largely stabilised, while emerging of ethylidene diacetate and vinyl acetate is DME (24) economies like China and India have huge consumption which ensures the highest selectivity, because the potential in acetic acid downstream segments such as WGSR is not possible (27). vinyl acetate monomer, purifi ed terephthalic acid, ethyl 3.3 Hydroformylation of Ethene acetate and acetic anhydride (22). Hydroformylation (oxo synthesis) of unsaturated 3.2 Production of Vinyl Acetate via Ethylidene substrates was discovered by Otto Roelen in 1938 Diacetate (28, 29) and was originally performed using a As mentioned above, when carbonylation is carried out heterogeneous Co catalyst. Further research revealed in excess methanol, methyl acetate may be synthesised a range of metals (Rh, Co, Ir, Ru, Mn and Fe) able to as well as acetic acid (23). Further reductive catalyse the process (Table II) (30). carbonylation of methyl acetate leads to formation of In commercial processes different metal-based ethylidene diacetate (24), which after hydrolysis yields catalysts are used and the most effective among vinyl acetate. Vinyl acetate monomer is well-known as them are Rh-based complexes. As can be seen one of the most important chemical raw materials (25), from Table II, the activity of the Rh catalyst

Equations (iii) and (iv): [HRh(CO)(PPh3)3] exceeds that of the Co catalyst [HCo(CO)4] by three orders of magnitude. The 2СН СООСН + 2СО + Н → СН СН(ОСОСН ) 3 3 2 3 3 2 Rh-based catalyst is more selective (linear:branched + СН СООН (iii) 3 aldehyde ratio 19:1 compared with 4:1) and can be

СН3СН(ОСОСН3)2 → СН2=СНОСОСН3 operated at lower pressures (7 atm–25 atm compared + СН3СООН (iv) with 200 atm–300 atm) (31). The beneﬁ t of using a

Table II Relative Activity of Different Metals in Hydroformylation (30) Мetal Rh Co Ir Ru Mn Fe Lg A3 0 –1–2–4–6

Rh-based catalyst in hydroformylation is economic chain termination and the formation of diketones may effi ciency, especially after the two-stage Ruhrchemie/ help the WGSR. The reaction was therefore promoted Rhone-Poulenc (RCH/RP) process was developed, by the addition of amines into the reaction mixture. eliminating the need to separate the used catalyst from Both selectivity of oligomerisation and the chain length the products (21). of products obtained strongly depend on the nature At present commercial hydroformylation is the key and the structure of the phosphine ligand (33). step in production of fatty alcohols based on dimers One of the low molecular weight products which and trimers of propylene and butenes. can be formed during the cooligomerisation of ethene and CO in the presence of methanol, 3.4 Cooligomerisation of Ethene and Carbon involving the isomerisation of active centres, is Monoxide methyl propanoate. Synthesis of methyl propanoate Alternate copolymerisation of olefi ns and CO is usually by methoxycarbonylation of ethene requires the carried out in the presence of Pd-containing catalysts and participation of equimolar quantities of ethene, leads to the formation of 1,4-polyketones (γ-polyketones). methanol and CO (Figure 2, R = OMe). The synthesis The latter represent copolymers with unique properties is catalysed by Pd complexes with the sterically bulky (high crystallinity, excellent mechanical properties and bidentate phosphine ligands. high chemical stability) (32, 33). Methoxycarbonylation of ethene was commercialised Shell developed commercial production of the fi rst while developing the Lucite Alpha process in 2008 polyketone in 1996, but discontinued it in 2000 (34, 35). (41). The fi rst step is interaction of ethene, CO and The product, marketed under the trade name of Carilon®, methanol to produce methyl propanoate; the second was an olefi n/CO alternate copolymer containing ethene step is the reaction of methyl propanoate and and a small amount (5%–10%) of propylene units. Today formaldehyde to form methyl methacrylate (Figure 3). SRI International, USA, offers polyketone thermoplastic The carbonylation step has a complex highly selective polymers. The material is currently produced under the mechanism with two kinds of catalytic cycles starting brand name Karilon by industrial conglomerate Hyosung from both methoxy- and hydrido-Pd species (Figure 4). Corporation, South Korea, in a pilot plant, but there are This reaction is catalysed by adducts of Pd salts with plans for a continuous plant that would come on-stream biphosphine that have tertiary substituents at the in 2015 (36). phosphorus atom allowing the polymerisation process A similar reaction of ethene and CO proceeding in to be suppressed (42). The commercial Lucite Alpha methanol can lead to low molecular weight products. process uses 1,2-bis(di-tert-butylphosphinomethyl)- The latter represent valuable raw materials for the benzene as a phosphine ligand. production of methyl methacrylate, among them methyl Methyl methacrylate monomer is an important propanoate (37) and diethyl ketone as a ‘green’ solvent marketable product. Its main applications are the (Figure 2) (38). These reactions are catalysed by Pd production of polymethylmethacrylate and acrylic complexes with phosphine ligands under relatively low resin. Global growth in the consumption of methyl pressures (39, 40). A source of hydrogen that leads to methacrylate is forecast to be 4.0% on average annually during 2011–2017 and its global market will reach 3.2 million tons by 2017 (43). R It is worth mentioning carbonylation processes which CH3OH C H + CO R = C2H5, do not use CO as a direct raw material (44). In such 2 4 ( OMe ) cases different carbonyl-containing compounds (most O often formates) are used as carbonyl group donors. Fig. 2. Feasible products during interaction of CO and An example is the formation of methyl propanoate by ethene in methanol in the presence of pgm catalysts reaction of ethene with methyl formate, catalysed by Ru

OMe OMe H2CO C2H4 + CO + CH3OH

O O

Fig. 3. Scheme of Lucite Alpha methyl methacrylate process

O [Pd] [Pd] CO C2H4 H O OMe MeOH

H2 + O P C O [Pd] [Pd] Pd CH2 [Pd] [Pd] O P H O B O A

P + CO C2H4 [Pd] = Pd P MeOH Fig. 4. Mechanism of ethene methoxycarbonylation

catalysts (Figure 5). This reaction is more ecologically is estimated as 6.5 million tons per year (46). The friendly than the reaction that directly uses CO. The global vinyl acetate monomer market is expected to methyl formate needed for this reaction may be formed g r o w a t a n av e r a g e r a t e o f 5% o v e r t h e f o r e c a s t p e r i o d by copper-catalysed methanol carbonylation (45). from 2012 to 2020, and at a much higher rate in the Synthesis of methyl formate and further formation Asia-Pacific region, particularly in China. Process of methyl propanoate taken together represent an modernisation means that BP has decreased alternative to methoxycarbonylation processes. its operating costs by a factor of three; similarly, Celanese managed to increase productivity by 95% (Praxair – by 5%) and to decrease costs by 15%. O [Ru] OMe C2H4 + In addition to the production of vinyl acetate from H OMe O ethylidene diacetate which in turn can be produced by the reductive carboxylation of methyl acetate, vinyl acetate can be produced by the reaction of ethene O [Ru] with acetic acid (Figure 6). This reaction is catalysed CO + MeOH by the homogeneous catalyst PdCl2/CuCl2 at optimal H OMe temperatures of 110°C–130°C and pressures of 30 atm–40 atm. However, such operating conditions Fig. 5. Ruthenium-catalysed reaction of ethene and methyl formate are extremely corrosive to the processing equipment. Heterogeneous Pd/Au catalysts have now been developed that avoid this shortcoming. The newly designed catalysts ensure selectivity of up to 94% 3.4.1 Preparation of Vinyl Acetate to ethene and up to 99% to acetic acid. When the Vinyl acetate is another important monomer for the process is carried out in a ﬂ uidised bed reactor the production of various polymers. Its world production capital costs may decrease by 30% (46). Recently a

by Co; however, pgm catalysts are increasingly being O C2H4 + CH3COOH used. Such catalysts possess higher activity and O selectivity, ensuring higher relative effi ciency of the Fig. 6. Palladium-catalysed vinyl acetate production from whole process. ethene and acetic acid 5. Carbonylation as a Component Part of a New Gas-to-Liquid Process number of large scale vinyl acetate plants have been constructed in China, India, Iran and Saudi Arabia. A new route for alternative GTL based on carbonylation has been proposed recently by the present authors (55). 4. Commercial Carbonylation of Methanol and It consists of direct partial oxidation of hydrocarbon Ethene gases into methanol and/or ethene followed by catalytic carbonylation of the latter. The main steps of Those pgm-catalysed carbonylation processes conventional GTL and the suggested alternative GTL mentioned above that have been successfully process are shown in Figure 7. commercialised are listed in Table III. It can be seen The fi rst step of the suggested alternative GTL from Table III that there is signifi cant commercial process consists of direct oxidative conversion; for experience in the realisation of processes including example: the partial oxidation of methane to methanol pgm-catalysed carbonylation to form a wide range of (56); the partial oxidation of heavy components of valuable petrochemicals. A number of these processes associated petroleum gas to methanol and CO (57); may be performed only in the presence of pgm or the oxidative cracking of heavy components of catalysts. Hydroformylation was originally catalysed associated petroleum gas to form ethene and CO

Table III Commercial Processes Including the Step of Methanol and Ethene Carbonylation Operating Operating Start- Metal/ Process Products temperature, pressure, Licensor up Production Reference Catalyst °C atm time Union Hydroformylation Carbide 1948 Rh overall on of ethene and Aldehydes, Company H[Rh(CO) 100 20 Rh ~2.3×106 (47, 29) propylene (oxo- alcohols Ruhrchemie/ (PAr)3] t/a (2002) synthesis) Rhone- 1986 Poulenc Rh − Monsanto Acetic acid, [Rh(CO)2I2] 1970 ~10.5×106 Carbonylation of Celanese methyl (active species) 180 30 t/a (22, 48, 49) methanol acetate Ir BP (CativaTM (2012) − 1996 [Ir(CO)2I2] process) National Pd Interaction of Distillers PdCl /CuCl ~3.5×106 t/a ethene and Vinyl acetate 2 2 130 40 Products 1986 (50–52) or supported (2007) acetic acid Bayer- Pd/Au Hoechst Pd Shell 7000 t/a Ethene-CO various Pd- Polyketone 100 20 (Carilon®) 1996 (discontinued (53) copolymerisation phosphine BP (Ketonex®) in 2000) complexes Pd 0.1×106 t/a Pd (dba) + Ethene 2 3 (2008) Methyl 1,2-bis(di-tert- Lucite (Alpha Carbomethoxy- 120 20 1998 0.1×106 (41, 54) methacrylate butylphosphino- process) ation t/a (under methyl) construction) benzene

CONVENTIONAL GTL TECHNOLOGIES

I. Oxidation step II. Catalytic step III. Hydroprocessing step

Natural or Syngas Fischer- Syngas Syncrude Tropsch Hydro- Fuels generation processing associated Co, Fe synthesis Lubricants petroleum gas

ALTERNATIVE GTL TECHNOLOGIES

I. Oxidation step II. Catalytic step Methanol, ethylene, Natural or Oxidative CO conversion Carbonylation associated Pd, Rh, Ir, petroleum Ru gas Petrochemicals

Fig. 7. The main steps of conventional and suggested alternative GTL-technologies

(58). The further processing of gas-vapour mixtures developing GTL technologies for the production of containing methanol, ethene and CO may give a broad sulfur-free synthetic fuels with high octane numbers assortment of value-added GTL products. (59). Among them the only companies with industrial This approach to gas conversion is particularly scale FT GTL facilities are Shell (Malaysia and Qatar), attractive because CO can be formed, along with the Sasol (South Africa and Qatar), PetroSA (South Africa) substrates (methanol and ethene), during the partial and Chevron (Nigeria). oxidation of natural gas in quantities sufﬁ cient for a Current FT-based GTL technologies are most further carbonylation step. Therefore there is no need effective as large scale projects with a capacity for energy consuming steam conversion or oxidation of of 30,000–150,000 barrels per day (bpd). GTL methane into syngas. This allows the development of an plants in use at Oryx GTL and Pearl GTL (Qatar), integrated two-stage gas conversion process that gives Escravos (Nigeria) and Nippon GTL (Japan), as a broad range of GTL products such as diethylketone, well as Bintulu (Malaysia) and Mossel Bay (South methylacetate, dimethylcarbonate, methylpropanoate, Africa) which are under construction at the time of ethylidene diacetate, oligoketones and polyketones writing, represent extremely complex and energy- (Figure 8), without the need to separate intermediate and capital-intensive facilities. The capital cost of products. the megaproject Shell Pearl in Qatar with a capacity of 140,000 bpd exceeds US$20 billion, meaning that 6. Challenges for Commercial Fischer-Tropsch the capital cost per 1 bpd of synthetic oil is more and Carbonylation Processes than US$140,000. Chevron Escravos in Nigeria had a total capital cost of US$8.4 billion, i.e. the capital Shell, Sasol, ChevronTexaco, Retch, Syntroleum Corp, cost per 1 bpd of synthetic oil is around US$200,000. Statoil and other petrochemical companies are currently The evolution of GTL processes using Fe and Co

Rh, Ir, 30 atm, 180ºC Acetic acid

Methylacetate Rh carbonylation, Reactive distillation Methanol + Ethylidendiacetate Rh/PPh3, 25–50 atm, CO 150–200ºC

Vinylacetate Pd, 30–40 atm, 110–130ºC

Methylpropanoate Pd, 70–120ºC, 1–200 atm

Ethylene + Propanal CO Rh, 100ºC, 20 atm

Diethylketone Pd, 30–70ºC, 1 atm

Oligoketones Pd, Rh

Fig. 8. Potential marketable products of catalytic carbonylation

catalysts seems unlikely due to the difficulty of also a broad assortment of different petrochemicals increasing their productivity any further. with high added value (60). This approach lowers Thus, despite the interest, the main challenges the investment risks in comparison with production and restrictions to the broad expansion of GTL-FT of synthetic fuel as the only marketable product. technologies are capital costs, changes in the oil/gas Sasol produces more than 100 products (acids, price ratio and volatile prices of GTL products. GTL alcohols, ketones, olefins) from its high-temperature products also have to compete with cheaper products FT process for supply to the market, among them from crude oil (gasoline, diesel, jet and stove fuel) in only a few fuels. This demonstrates the potential the consumer market. In recent years, the stimulus for alternative GTL to produce value-added of GTL has turned to another force: the desire to products. transform stranded or ﬂ ared natural gases into money The operating characteristics of conventional GTL by converting these into high value-added marketable technologies based on FT synthesis in comparison chemicals. with the suggested integrated process including For example, Sasol’s GTL-FT facilities are flexible carbonylation in the presence of pgm catalysts are for the production of not only synthetic liquid fuels but given in Table IV.

Table IV Comparative Data on Conventional FT GTL and Integrated Process including Platinum Group Metal Catalysed Carbonylation Parameter Conventional FT GTL Carbonylation based GTL Temperature, °С 220–330 100–200 Pressure, atm 20–30 10–60 Catalysts Co, Fe pgm 250–400 1.1–0.3 (conventional); Speciﬁ c activity of catalyst, kg/kg h (for Rh-catalysed Up to 2 (microchannel) hydroformylation) (Continued)

Table IV Comparative Data on Conventional FT GTL and Integrated Process including Platinum Group Metal Catalysed Carbonylation (Continued) Parameter Conventional FT GTL Carbonylation based GTL Reactor size Huge Ordinary Expensive step for syngas production Required Not required

Steam conversion: no need for O2; Oxidant (industrial O2) Partial oxidation and ATR: need Need for O2 for O2 Additional step for reductive Required Not required isomerisation Final products Syncrude, fuels, lubricants Petrochemicals Product puriﬁ cation Required Required Availability for small-scale production or Economically unreasonable Economically reasonable direct use in oil/gas ﬁ elds

Capital cost per unit, US$/bpd ˃140,000 ~50,000

Conclusion 2005, 74, (12), 1111 6. R. N. Magomedov, A. Yu. Proshina and V. S. Arutyunov, The present review indicates that in some cases Kinet. Catal., 2013, 54, (4), 383 alternative GTL processes based on carbonylation 7. R. N. Magomedov, A. Yu. Proshina, B. V. Peshnev will be able to take their own segment in the existing and V. S. Arutyunov, Kinet. Catal., 2013, 54, petrochemical markets, especially for remote areas (4), 394 and short life oil/gas pools. In order to perform such 8. T. A. Bazhenova and A. E. Shilov, Coord. Chem. Rev., alternative processes it is advisable to use pgm 1995, 144, 69 catalysts because of their high activity and selectivity. 9. Johnson Matthey base prices in US$ per troy oz: This type of process can be used for the monetisation http://www.platinum.matthey.com/prices/price-tables of stranded natural and associated petroleum gases (Accessed on 24th October 2014) by converting them into marketable products with high 10. V. I. Savchenko, I. A. Makaryan and V. G. Dorokhov, added value. Platinum Metals Rev., 1997, 41, (4), 176 References 11. V. I. Savchenko and I. A. Makaryan, Platinum Metals Rev., 1999, 43, (2), 74 1. E. F. Sousa-Aguiar, F. B. Noronha and A. Faro, Jr, 12. A. E. Shilov and G. B. Shul’pin, Chem. Rev., 1997, 97, Catal. Sci. Technol., 2011, 1, (5), 698 (8), 2879 2. NEXT-GTL Result In Brief, ‘Making Better Use 13. O. M. Chukanova, K. A. Alpherov and G. P. Belov, J. of Natural Gas’, Project Reference 229183, Mol. Catal. A: Chem., 2010, 325, (1–2), 60 Record Number 91099, Community Research and Development Information Service (CORDIS), 14. W. Reppe, H. Friederich, N. von Kutepow and W. Luxembourg, 4th July, 2014 Morsch, BASF AG, ‘Process for the Production of Aliphatic Oxygen Compounds By Carbonylation of 3. G. A. Olah, A. Goeppert and G. K. S. Prakash, “Beyond Alcohols, Ethers, and Esters’, US Patent 2,729,651; Oil and Gas: The Methanol Economy”, 2nd Edn., 1956 Wiley-VCH Verlag GmbH & Co KGaA, Weinheim, Germany, 2009 15. A. Haynes, Adv. Catal., 2010, 53, 1 4. ‘Periodic Report Summary 2’, Oxidative Coupling 16. A. Behr and P. Neubert, “Applied Homogeneous of Methane followed by Oligomerisation to Liquids Catalysis”, Wiley-VCH Verlag & Co KGaA, Weinheim, (OCMOL), Project reference 228953, Record Number Germany, 2012

53847, Community Research and Development 17. K. G. Moloy and J. L. Petersen, Organometallics, Information Service (CORDIS), Ghent, Belgium, 28th 1995, 14, (6), 2931 May, 2014 18. B. Liu and S. F. Ji, Adv. Mater. Res., 2012, 610–613, 5. V. S. Arutyunov and O. V. Krylov, Russ. Chem. Rev., 2600

19. J. R. Zoeller, Catal. Today, 2009, 140, (3–4), 118 December 2013, p. 36 20. A. Haynes, P. M. Maitlis, G. E. Morris, G. J. Sunley, H. 37. G. R. Eastham, R. P. Tooze, M. Kilner, D. F. Foster Adams, P. W. Badger, C. M. Bowers, D. B. Cook, P. I. and D. J. Cole-Hamilton, J. Chem. Soc. Dalton Trans., P. Elliott, T. Ghaffar, H. Green, T. R. Griffi n, M. Payne, 2002, (8), 1613 J. M. Pearson, M. J. Taylor, P. W. Vickers and R. J. 38. V. N. Zudin, G. N. Il’inich, V. A. Likholobov and Y. I. Watt, J. Am. Chem. Soc., 2004, 126, (9), 2847 Yermakov, J. Chem. Soc., Chem. Commun., 1984, 21. ‘Acetic Acid Market for VAM, PTA, Acetate Esters, (8), 545 Acetic Anhydride and Other Applications – Global 39. G. Cavinato, L. Toniolo and A. Vavasori, Industry Analysis, Size, Share, Growth, Trends ‘Carbonylation of Ethene in Methanol Catalysed and Forecast, 2012–2018’, Transparency Market by Cationic Phosphine Complexes of Pd(II): from Research, Albany, New York, USA, 3rd October, 2013 Polyketones to Monocarbonylated Products’, in 22. ‘Global Acetic Acid Market Estimated to Reach 15.5 “Catalytic Carbonylation Reactions”, ed. M. Beller, Million Tons by 2020’, Plastemart, Mumbai, India, 14th Topics in Organometallic Chemistry, Springer- February, 2013 Verlag, Berlin, Heidelberg, Germany, 2006, Vol. 18, 23. P. Cheung, A. Bhan, G. J. Sunley and E. Iglesia, pp. 125–164 Angew. Chem. Int. Ed., 2006, 45, (10), 1617 40. R. A. M. Robertson and D. J. Cole-Hamilton, Coord. 24. D. Liu, X. Huang, L. Hu, D. Fang, W. Ying and D. Chem. Rev., 2002, 225, (1–2), 67 Chen, J. Nat. Gas Chem., 2010, 19, (2), 165 41. B. Harris, ‘Acrylics for the Future’, Ingenia, December 25. N. Rizkalla and R. Vale, The Halcon SD Group, Inc, 2010, Issue 45, p. 19 ‘Preparation of Carboxylic Acid Anhydrides’, US 42. P. W. N. M. van Leeuwen and Z. Freixa, ‘Bite Angle Patent 4,483,803; 1984 Effects of Diphosphines in Carbonylation Reactions’, 26. F. J. Waller, Air Products and Chemicals, Inc, ‘Process in “Modern Carbonylation Methods”, ed. L. Kollár, for Converting Dimethyl Ether to Ethylidene Diacetate”, Wiley-VCH Verlag GmbH & Co KGaA, Weinheim, European Patent 0,566,371; 1993 Germany, 2008 27. A. Haynes, ‘Acetic Acid Synthesis by Catalytic 43. ‘Methyl Methacrylate: A Global Strategic Business Carbonylation of Methanol’, in “Catalytic Carbonylation Report’, Global Industry Analysts Inc, San Jose, Reactions”, ed. M. Beller, Topics in Organometallic California, USA, February, 2013 Chemistry, Springer-Verlag, Berlin, Heidelberg, 44. T. Morimoto and K. Kakiuchi, Angew. Chem. Int. Ed., Germany, 2006, Vol. 18, pp. 179–205 2004, 43, (42), 5580 28. O. Roelen, Chemische Verwertungsgesellsch, 45. L. He, H. Liu, C.-x. Xiao and Y. Kou, Green Chem., ‘Verfahren zur Herstellung von sauerstoffhaltigen 2008, 10, (6), 619 Verbindungen’, German Patent 849,548; 1938 46. G. Roscher, ‘Vinyl Esters’ in “Ullmans’s Encyclopedia 29. B. Cornils, W. A. Herrmann and M. Rasch, Angew. of Industrial Chemistry”, Wiley-VCH Verlag GmbH & Chem. Int. Ed., 1994, 33, (21), 2144 Co KGaA, Weinheim, Germany, 2007 30. K.-D. Wiese and D. Obst, ‘Hydroformylation’, in 47. S. N. Bitzzari, R. Gubler and A. Kishi, ‘Oxo “Catalytic Carbonylation Reactions”, ed. M. Beller, Chemicals’, in “Chemical Economics Handbook”, Topics in Organometallic Chemistry, Springer-Verlag, SRI International, Report number 682.7000, 2002, Berlin, Heidelberg, Germany, 2006, Vol. 18, pp. 1–33 pp. 1–121 31. “Aqueous-Phase Organometallic Catalysis: Concepts 48. K. Weissermel and H.-J. Arpe, “Industrial Organic and Applications”, 2nd Edn., eds. B. Cornils and W. Chemistry”, 4th Edn., Wiley-VCH Verlag GmbH & Co A. Herrmann, Wiley-VCH Verlag GmbH & Co KGaA, KGaA, Weinheim, Germany, 2003 Weinheim, Germany, 2004 32. G. P. Belov and E. V. Novikova, Russ. Chem. Rev., 49. I. Conn, ‘Refi ning & Marketing Welcome’, Refi ning 2004, 73, (3), 267 and Marketing Investor Day, BP Plc, Pangbourne, UK, 30th November, 2011 33. E. Drent and P. H. M. Budzelaar, Chem. Rev., 1996, 50. I. I. Moiseev, M. N. Vargaftik and Ya. K. Syrkin, Dokl. 96, (2), 663 Akad. Nauk SSSR, 1960, 133, 377 34. H. Seifert, Kunststoffe, 1998, 88, 1154 51. H. Fernholz, H.-J. Schmidt, F. Wunder, Hoechst 35. F. Garbassi, Chemtech, 1999, 29, (10), 48 AG, ‘Process for the Manufacture of Vinyl Esters of 36. ‘Polyketone returns’, Injection World, November/ Carboxylic Acids’, German Patent 1,296,138; 1967

52. R. E. Robinson, National Distillers, ‘Process for Foundations and Prospects of the Process”, Elsevier Preparing Esters’, US Patent 3,190,912; 1965 BV, Amsterdam, The Netherlands, 2014 53. E. Brulé, J. Guo, G. W. Coates and C. M. Thomas, 57. V. S. Arutyunov, E. V. Sheverdenkin, V. M. Rudakov Macromol. Rapid Comm., 2011, 32, (2), 169 and V. I. Savchenko, Stud. Surf. Sci. Catal., 2004, 54. G. R. Eastham, M. Waugh and P. I. Richards, Lucite 147, 703 International UK Limited, ‘Carbonylation of Ethylenically 58. V. S. Arutyunov and R. N. Magomedov, Russ. Chem. Unsaturated Compounds’, World Appl. 2007/057,640 Rev., 2012, 81, (9), 790 55. V. I. Savchenko, I. A. Makaryan, I. G. Fokin, I. V. Sedov, 59. D. A. Wood, C. Nwaoha and B. F. Towler, J. Nat. Gas R. N. Magomedov, M. G. Lipilin and V. S. Arutyunov, Sci. Eng., 2012, 9, 196 Neftepererabotka i Neftechimiya, 2013, (8), 21 60. A. P. Steynberg, R. L. Espinoza, B. Jager and 56. V. Arutyunov, “Direct Methane to Methanol: A. C. Vosloo, Appl. Catal. A: Gen., 1999, 186, (1–2), 41

The Authors

Iren A. Makaryan obtained her PhD in Chemistry from the Institute of Problems of Chemical Physics at the Russian Academy of Sciences (RAS), Chernogolovka, Moscow Region, Russia, under the supervision of Professor Valery I. Savchenko. She is currently Head of the Techno-Economic and Market Research Group. Her research interests include kinetics and mechanism of pgm catalysed reactions, commercialisation of newly designed processes and market analysis.

Igor V. Sedov obtained his PhD in Chemistry from the Institute of Problems of Chemical Physics RAS, Chernogolovka, under the supervision of Professor Petr E. Matkovskiy in 2011. He is now Head of the Petrochemical Processes Laboratory at the institute. His interests include organometallic catalysis, chemical technology and engineering.

Professor Valery I. Savchenko has been Head of the Department of Chemical Technology at the Institute of Problems of Chemical Physics RAS, Chernogolovka, since 1991. He also lectures on Modern Petrochemical Processes at the Lomonosov Moscow State University, Russia. His research is devoted to a wide range of problems in the ﬁ eld of chemical physics and chemical technology, including catalysis, kinetics, reaction mechanisms and reaction engineering. He has helped develop and commercialise a number of novel chemical and petrochemical processes.

“Nanomaterials for Lithium-Ion Batteries: Fundamentals and Applications”

Edited by Rachid Yazami (Nanyang Technological University, Singapore), Pan Stanford Publishing Pte Ltd, USA, 2014, 448 pages, ISBN: 978-981-4316-40-8, £95.00, US$149.95

Reviewed by Sarah Ball electrodes. The chapter describes how the preparation Johnson Matthey Technology Centre, Blounts Court, of thin layers or nanoscale structures can mitigate this Sonning Common, Reading, RG4 9NH, UK volume change (Figure 1), but other aspects such as instability of the solid electrolyte interphase (SEI), Email: [email protected] cracking and detachment from the current collector with cycles are also important considerations. Methods to make silicon nanowires are discussed and the “Nanomaterials for Lithium-Ion Batteries: Fundamentals structural changes from the initial crystalline state to an and Applications” is edited by Rachid Yazami and is amorphous structure after the fi rst cycle are explained. published by Pan Stanford Publishing Pte Ltd. The book Chapter 2, ‘Nanoscale Anodes of Silicon and covers the latest developments in new materials for Germanium for Lithium Batteries’ by Jason Graetz and lithium-ion batteries including examples of novel alloys, Feng Wang (Brookhaven National Laboratory, USA), oxides and conversion materials for use as anodes extends the discussion to cover additional elements and phosphates, high voltage spinels and layered which can alloy with Li, then focuses on Si and Ge, both oxides for use as cathodes. Composite structures of which can achieve high capacity at a low voltage. incorporating reduced graphene oxide are considered Again the use of nanostructures is key to mitigate along with thin fi lms and nanowires. Emphasis is also volume expansion issues and dissipate strain more placed on combining electrochemical test data with readily during the expansion observed on lithiation of materials characterisation and detailed explanation of the material. Electrochemistry and cycling behaviour of the mechanisms occurring. thin fi lms of Si and Ge are compared and the chapter concludes by commenting on the possible benefi ts of Advanced Anode Materials Si and Ge electrodes in solid state batteries and the requirement for materials engineering of composite Chapter 1, ‘Silicon Nanowire Electrodes for Lithium-Ion structures to stop pulverisation and decrepitation with Battery Negative Electrodes’ by Candace K. Chan cycles. (Arizona State University, USA) and Matthew T. Chapter 3, ‘Nano-Electrochemical Approach for McDowell and Yi Cui (Stanford University, USA), Improvement of Lithium-Tin Alloy Anode’ by Tetsuya describes the advantages and challenges of Osaka, Hiroki Nara and Hitomi Mukaibo (Waseda nanostructured silicon as an anode material. The University, Japan), describes the promise of tin and tin signifi cantly enhanced capacity of silicon over alloys as Li storage materials. The approach of adding conventional graphite electrodes is also associated with an inert spacer or scaffold element such as nickel to the a huge volume change of ~300% on lithiation of silicon tin is described, as Ni does not react with Li. Results

(a) Initial substrate After cycling

Film

Particles

(b)

Nanowires

Facile strain Efﬁ cient 1D relaxation electron transport

Good contact with current collector Fig. 1. Schematic of morphological changes that occur in Si during electrochemical cycling. (Reproduced with permission from (1). Copyright (2008) Nature Publishing Group)

of electrochemical testing and characterisation (X-ray the electrolyte with Si and mitigate volume expansion diffraction (XRD), transmission electron microscopy issues, all of which lead to good performance and (TEM) and electron diffraction) are shown for fi lms with cyclability, especially at lower temperatures. various Sn:Ni ratios to illustrate the phases formed and Chapter 5, ‘Nanometer Anode Materials for Li-Ion the processes occurring; fi lm composition Sn:Ni 62:38 Batteries’ by Xuejie Huang and Hong Li (Chinese showed the best performance. Calculations and in Academy of Sciences, China) describes the important situ methods to measure stress on the electrode layer features of anodes (low Li insertion and removal as a result of volume expansion are also described. voltage, high capacity, low volume change, stability Preparation of mesoporous Sn is also covered which to electrolyte reactions, abundance and low cost) shows improved cycling performance over denser Sn and also the various types of anode material (oxide, anodes. alloy, conversion) that are available. Examples of Chapter 4, ‘Alloy Electrode and Its Breakthrough these different anode Li storage approaches are also Technology’ by Kiyotaka Yasuda (Mitsui Mining and provided, in particular the properties of transition metal Smelting Co Ltd, Japan) provides a more historical oxide conversion materials. In such materials the metal perspective on the different types of anodes (Li metal oxide is converted to metal nanoparticles within a matrix and various alloy types) and also describes the different of Li oxide by the lithiation process. The importance of types of alloying reactions (internal displacement, achieving high mass and also high volumetric capacity phase separation and mixed reaction). The approach for novel materials when comparing with currently used used by Mitsui in its SILX project on silicon based graphites is also emphasised. anodes is then discussed. Si particles are covered Chapter 6, ‘Lithium Reaction with Metal Nanofi lms’ with a thin copper layer and formed into an electrode by Rachid Yazami provides a concise and systematic structure with ~30% cavity space. These features lead description of the properties of different metal nanofi lms to good conductivity, prevent unwanted reaction of during lithiation covering both non-alloying metals

(where the only modes of Li storage are reaction with surface oxides and storage in micro cracks) and alloying metals (where incorporation of Li into the metal also takes place).

Cathode Materials

In Chapter 7, ‘High-Rate Li-Ion Intercalation in Nanocrystalline Cathode Materials for High-Power 5 nm 2 nm Li-ion Batteries’, Masashi Okubo (National Institute of Advanced Industrial Science and Technology, Japan) and Itaru Honma (Institute of Multidisciplinary Research for Advanced Materials, Japan) discuss the properties of lithium cobalt oxide (LiCoO2) which is currently widely used as a lithium-ion battery cathode material. Theoretical and experimental aspects of this material are covered, such as correlation between lithium diffusion distances and high rate capability. Chapters 8 and 9 cover an alternative cathode material, 5 nm 2 nm lithium iron phosphate (LiFePO4), which is safer, lower cost and effective at high rates when made at nanosize and carbon coated (Figure 2). Chapter 8, ‘LiFePO4: From an Insulator to a Robust Cathode Material’ by Miran Gaberšček (National Institute of Chemistry, Slovenia) et al. is excellent, covering theoretical and experimental properties of LiFePO4 from single crystals through to nanomaterials in electrode layers. The effect of size, models for different types of electrochemical contacting of active particles and network effects in 5 nm cathode layers are all well explained. Chapter 9, 2 nm ‘Redox Reaction in Size-Controlled Li FePO by x 4 Fig. 2. TEM images of carbon coated LiFePO4 Atsuo Yamada (The University of Tokyo, Japan) further elucidates the behaviour of LiFePO4, covering redox reactions and the effect of particle size on the phase restacking of RGO and hence allowing good capacity diagram; the adverse effects of exposure of LiFePO4 and performance at high C-rates. Such materials may to air which causes oxidation of surface Fe are also be made by microwave assisted hydrothermal synthesis discussed. and cathode (lithium manganese oxide (LiMnO4)/RGO) and anode (Li4Ti5O12/RGO) are both covered. Hybrid Materials and Practical Considerations The ﬁ nal chapter of this book turns to more practical considerations and how the advanced materials already Chapter 10, ‘Reduced Graphene Oxide–Based Hybrid discussed can be effectively utilised to give high power Materials for High-Rate Lithium Ion Batteries’ by Seong and/or high energy in real cells. Chapter 11, ‘High- Min Bak, Hyun Kyung Kim, Sang Hoon Park and Energy and High-Power Li-Ion Cells: Practical Interest/ Kwang Bum Kim (Yonsei University, Republic of Korea) Limitation of Nanomaterials and Nanostructuration’ summarises the advantages and requirements for is by S. Jouanneau, S. Patoux, Y. Reynier and reduced graphene oxide (RGO) composite materials for S. Martinet (Commissariat à l’énergie atomique et aux both cathodes and anodes. These advantages include énergies alternatives (CEA) Laboratory for Innovation good conductivity and the ability to form small, well in New Energy Technologies and Nanomaterials dispersed metal oxide particles on the RGO surface, (LITEN), France). The advantages and challenges of preventing agglomeration of oxide particles and a wide range of nanomaterials for cathodes, including

highlighted. Strategies to control volume expansion olivine type lithium metal phosphates, layered oxides and limit material degradation with cycles via the and high voltage spinels with various metal contents, preparation of composite materials and nanostructures, are discussed. Experience with novel Si/C composite coatings or doping also feature across a wide number anodes and titanium oxides and titanates is also of the examples used. reviewed. The requirements for more stable high voltage electrolytes or appropriate additives to accompany these advanced materials are also considered along Reference with binder and processing aspects. The chapter 1. C. K. Chan, H. Peng, G. Liu, K. McIlwrath, X. F. Zhang, provides an overview of the potential usefulness of R. A. Huggins and Y. Cui, Nature Nanotechnol., nanomaterials for battery applications. 2008, 3, (1), 31

Conclusions "Nanomaterials for This book provides a very useful introduction to the Lithium-ion Batteries" forthcoming advanced nanomaterials for lithium-ion anodes and cathodes. Beneﬁ ts and disadvantages of a wide range of materials types are presented both in the context of fundamental materials properties and challenges of incorporating nanomaterials into practical electrodes and cells. Common themes within the chapters are the beneﬁ ts of nanosizing materials in terms of shorter diffusion lengths, improved conductivity and better rate capability, but disadvantages such as low density and increased surface area leading to greater irreversible capacity and unstable SEI are also

The Reviewer

Dr Sarah Ball is a Senior Principal Scientist at the Johnson Matthey Technology Centre, Sonning Common, UK. In the last two years she has been involved in work on lithium air and lithium-ion batteries. Previously she was involved in fuel cell research on novel cathode materials including assessment of electrochemical stability, performance and properties.

“Electrolytes for Lithium and Lithium-Ion Batteries”

Edited by T. Richard Jow, Kang Xu, Oleg Borodin (US Army Research Laboratory, USA) and Makoto Ue (Mitsubishi Chemical Corporation, Japan), Series: Modern Aspects of Electrochemistry, Vol. 58, Springer Science+Business Media, New York, USA, 2014, 476 pages, ISBN: 978-1-4939-0301-6, £117.00, US$179.00, €135.19

Reviewed by Sarah Ball hydrolysis) and ability to form an optimal interphase at Johnson Matthey Technology Centre, Blounts Court, the electrodes. The chapter then provides an extremely Sonning Common, Reading, RG4 9NH, UK comprehensive coverage of the different types of lithium salts and their properties, ranging from established

Email: [email protected] salts such as lithium hexafl uorophosphate (LiPF6) and lithium bis(bistrifl uoromethanesulphonyl)imide (LiTFSI) to more advanced examples including organoborates, “Electrolytes for Lithium and Lithium-Ion Batteries”, phosphates and aluminates. Structure diagrams are published in 2014 by Springer, is Volume 58 in the included for all examples which greatly aid the reader Modern Aspects of Electrochemistry series. The and the chapter concludes by highlighting adoption volume is edited by T. Richard Jow, Kang Xu, Oleg criteria for new salts; the chapter also includes over Borodin and Makoto Ue. In the preface the Editors set 700 references. out their purpose in compiling this volume, which was Chapter 2, ‘Nonaqueous Electrolytes with Advances to provide a comprehensive overview of electrolytes for in Solvents’ by Makoto Ue, Yukio Sasaki (Tokyo lithium-ion batteries. It covers electrolyte research and Polytechnic University, Japan), Yasutaka Tanaka development in the last ten years and may be used (Shizuoka University, Japan) and Masayuki Morita as a foundation for future work and directions. The (Yamaguchi University, Japan), reviews the important volume succeeds in covering the multifaceted area solvent properties including high electrolytic of electrolytes in a logical and highly comprehensive conductivity, high chemical and electrochemical manner. stability, wide operating temperature range and high Chapter topics include lithium salts, advances in safety. Phase diagrams for a range of solvent mixtures solvents, additives and ionic liquids, then progressing to are shown and properties such as viscosity, conductivity understanding of the cathode and anode interphases, and stability are discussed for a range of cyclic and linear reviewing various characterisation approaches, a carbonates and fl uorinated versions thereof. The typical discussion of modelling approaches and fi nally future requirement to blend at least two electrolytes together to technologies such as lithium air batteries. achieve optimal properties, for example a combination of a cyclic carbonate (high dielectric constant to aid salt Salts, Solvents and Additives dissociation) and a linear carbonate (to lower viscosity) is discussed, along with benefi ts of fl uorinated solvents Chapter 1, ‘Nonaqueous Electrolytes: Advances to increase electrochemical performance and stability, in Lithium Salts’ by Wesley A. Henderson (Pacifi c use of organoborates to reduce weight, cost and toxicity Northwest National Laboratory, USA) begins with and the addition of phosphates as fl ame retardants. information on desirable salt properties such as ionic Polymer gel electrolytes and sulfur containing solvents conductivity, solubility, stability (to oxidation and are also reviewed.

Chapter 3, ‘Nonaqueous Electrolytes and Advances In addition various characterisation techniques in Additives’ by Koji Abe (UBE Industries Ltd, Japan), (including nuclear magnetic resonance (NMR) and is partly told from a historical perspective, but also X-ray photoelectron spectroscopy (XPS)) to explore classifi es the different additive types according to their the SEI composition are discussed. The extension to function and safety. The intentional addition of additives more advanced anodes such as silicon and additives to to control the solid electrolyte interphase (SEI) by aid SEI formation for various systems are also covered. forming a controlled thin layer with lower resistance to Chapter 6, ‘On the Surface Chemistry of Cathode Li mobility and additives for the formation of a stable Materials for Li-Ion Batteries’ by Susai Francis Amalraj, cathode interphase are discussed. Safety aspects Ronit Sharabi, Hadar Sclar and Doron Aurbach such as addition of species which can prevent thermal (Bar-Ilan University, Israel) provides a concise and runaway via surface polymerisation and additives practical introduction to the different cathode chemistry such as redox shuttles (for example, anisoles) and types (including layered oxides, spinels and olivines) other approaches to overcharge protection and fl ame and diagnostic methods to assess the cathode- retardant additives such as phosphates are also electrolyte interphase. Issues such as metal dissolution reviewed. from the cathode and subsequent precipitation at the Chapter 4, ‘Recent Advances in Ionic Liquids for anode (leading to performance loss) and the use of Lithium Secondary Batteries’ by Hajime Matsumoto additives or active materials coatings to control the (National Institute of Advanced Industrial Science and cathode interphase and limit unwanted side reactions Technology (AIST), Japan) describes the benefi cial are described. References to greater details in a properties of ionic liquids (ILs) such as reduced number of their own publications are also provided. fl ammability and volatility and covers examples of Chapter 7, ‘Tools and Methodologies for the their exploratory usage in full-cells. Important recent Characterization of Electrode–Electrolyte Interfaces’ by developments are the formulation of new anions Jordi Cabana (Lawrence Berkeley National Laboratory, (in particular asymmetric versions) which impact USA and University of Illinois, USA), provides a viscosity and improve mobility/conductivity, to achieve thorough and authoritative introduction to the various performance comparable to conventional electrolytes techniques to analyse electrode-electrolyte interfaces. using ILs. The high stability reported for ILs in individual Electrochemical techniques, various types of component analysis (thermal decomposition) is also spectroscopy (Raman, infrared (IR), XPS, NMR, X-ray shown to be reduced in the presence of active battery and neutron techniques), ellipsometry and microscopy components, illustrating the importance of realistic are all discussed with illustrative examples. To date testing scenarios. many experiments have been made ex situ, necessarily requiring a washing and electrolyte removal step that Interfaces and Surface Chemistry may infl uence the surface, so advances in cell design to allow measurement in the presence of electrolyte Chapter 5, ‘Interphases Between Electrolytes and are key to future progress. Also, the importance of Anodes in Li-Ion Battery’ by Mengqing Xu, Lidan Xing combining complementary techniques to fully assess and Weishan Li (South China Normal University) the interface properties is stressed along with possible covers the anode electrolyte interphase (referred overlaps with other areas in electrocatalysis. to as the SEI). It begins with a historical overview of initial work with Li anodes and graphite highlighting Modelling Methodologies how the unstable interphase formed with graphite and propylene carbonate (PC) electrolytes hampered Chapter 8, ‘Molecular Modeling of Electrolytes’ by Oleg initial studies and was revolutionised by the change Borodin describes the different methodologies for the to ethylene carbonate (EC) and other electrolytes modelling of electrolytes and stresses the importance which form a stable SEI with graphite anodes. The of considering clusters and systems rather than just mechanisms of SEI formation (two-dimensional (2D) the individual molecules and components. Validation and three-dimensional (3D)) and reduction products for of models against experimental data and also the various linear and cyclic carbonate solvent species that dangers of combining experimental results from create the SEI are discussed and the energy barriers to different sources (where details such as experimental Li motion through the interphase described (Figure 1). procedures and reference scales may vary) are

G≠ “Charge-transfer” activation energy

60~70 kJ mol–1

Reaction coordinate

Diffusion of solvated Li+ diffusion Li+ in bulk solution through SEI ﬁ lm

0.35 mm

Breakup of Li+ Li+ diffusion in solvation sheath graphene bulk

Fig. 1. Schematic description of energy barrier for “Li transfer” at graphite/electrolyte interphase (Reprinted with permission from (1). Copyright (2010) American Chemical Society)

highlighted. The use of molecular dynamics (MD) are also discussed, as more complex systems may be simulations to explore Li mobility within the SEI and the modelled and in particular realistic electrode materials different anode substrates (graphite, lithium titanate depictions, surfaces and multicomponent systems can and lithium lanthanum titanate) and hence decouple Li be explored more accurately. mobility in SEI from Li desolvation effects is described. Chapter 9, ‘Prediction of Electrolyte and Additive Future Technologies: Lithium Air Batteries Electrochemical Stabilities’ by Johan Scheers and Patrik Johansson (Chalmers University of Technology, The book closes with Chapter 10, ‘Aprotic Electrolytes in Sweden), covers different approaches to modelling the Li-Air Batteries’ by Kah Chun Lau, Rajeev S. Assary and potentials of oxidation and reduction of solvent, salt Larry A. Curtiss (Argonne National Laboratory, USA). and additive components of the electrolyte. Signiﬁ cant Lithium air batteries in theory present the possibility variations in predicted trends are found depending of exceptionally high capacities due to their low mass on the reaction products (linear or cyclic), route, constituents. However, the lack of stability of current mechanism and intermediates. Again issues with cross electrolytes in the presence of the superoxide radical comparison against different experimental results in generated in the cathode oxygen reduction reaction is the literature are pointed out, including varying sweep thought to be the greatest barrier to success in these rates, working electrodes, cut off currents and also systems. For many years common Li-ion electrolytes variations in the reference energies. In the case of such as PC were used in lithium air systems. However, redox shuttle, accurate predictions of potentials are superoxide attack results in formation of irreversible particularly important, as their behaviour links to battery lithium carbonate species, rather than the desired safety. The advantages of increasing computer power lithium peroxide (Figure 2). This chapter summarises

ever provide all the answers. This book provides an excellent guide to the plethora of salt, electrolyte and additive options and their functionalities and properties; the historical overview is also particularly helpful to those who are new to the ﬁ eld. In summary, this book will be useful to battery researchers in academia and industry, providing historical context, reference information on a wide range of electrolyte components and their functionality and highlighting directions for further work and the challenges that lie ahead. The use of examples to 200 nm illustrate materials properties, interplay between components, the different analytical techniques and Fig. 2. Lithium peroxide toroids formed on discharge in modelling approaches is particularly helpful along with a lithium air cathode. (Picture courtesy of the Analytical Department, Johnson Matthey Technology Centre, Sonning the large number of literature references cited on the Common, UK) different topics.

Reference the characterisation methods used to conﬁ rm the 1. K. Xu, A. von Cresce and U. Lee, Langmuir, 2010, 26, unsuitability of PC and the somewhat improved results (13), 11538 with ether based solvent and stresses the importance of understanding the reaction mechanisms and of Electrolytes for Lithium and interlinking theory and experiment to enable the search Lithium-ion Batteries for an improved electrolyte system.

Conclusions

Throughout the book certain themes emerge, including the importance of carefully correlating experimental results with modelling data and addressing multicomponent systems under realistic conditions rather than considering the individual constituents in isolation. It is also apparent that no one technique can

The Reviewer

Secondary Lithium-Ion Battery Anodes: From First Commercial Batteries to Recent Research Activities

Addressing the challenges in rechargeable lithium-ion battery technologies

By Nicholas Loeffl er, Dominic Bresser and 1. Introduction Stefano Passerini* Helmholtz Institute Ulm (HIU), Electrochemistry 1, Rechargeable (i.e. secondary) LIBs are now our Helmholtzstraße 11, 89081 Ulm, Germany; and everyday companions, powering our laptops, cellular Karlsruhe Institute of Technology (KIT), PO Box 3640, phones, tablets, portable audio players, etc. Due to 76021 Karlsruhe, Germany their high specifi c energy, superior coulombic effi ciency and outstanding cycle life compared to earlier battery Mark Copley** systems like lead-acid, nickel cadmium or nickel metal Johnson Matthey Technology Centre, Blount’s Court, hydride (1), LIBs quickly conquered the battery market Sonning Common, Reading, RG4 9NH, UK for consumer electronics (2) and are at present the power source of choice for these applications (3). In view Email: *[email protected]; of limited crude oil resources and climate endangering

**[email protected] emissions (e.g. CO2) deriving from the consumption of fossil fuels, LIB technology is currently facing a new great challenge: its implementation in large-scale Following the development of commercial secondary devices like (hybrid) electric vehicles and stationary lithium-ion batteries (LIBs), this article illustrates the energy storage to balance the intermittent supply of progress of therein-utilised anode materials from the renewable energy sources such as wind, solar and fi rst successful commercialisation to recent research tidal (3–5). Although some electric and hybrid vehicles activities. First, early scientifi c achievements and are now becoming available, the energy density of LIBs industrial developments in the fi eld of LIBs, which still needs to be substantially increased by a factor of enabled the remarkable evolution within the last 20 two to fi ve compared to the existing state-of-the-art years of this class of batteries, are reviewed. Afterwards, technology (150 Wh kg–1) to push these vehicles out the characteristics of state-of-the-art commercially of the niche market sector, paving the way for a fully available anode materials are highlighted with a sustainable transportation system (6). However, the particular focus on their lithium storage mechanism. conversion of electrical energy to chemical energy Finally, a new class of anode active materials exhibiting (and vice versa), corresponding to the charge (and a different storage mechanism, namely combined discharge) of a LIB, is a complicated process due to the conversion and alloying, is described, which might various participating components in a lithium-ion cell, successfully address the challenges and issues lithium- their (electro-)chemical properties and their extensive ion battery anodes are currently facing. interdependencies (4).

Generally, LIBs are built of two electrodes (anode lithium metal structures, which continuously grow, and cathode), separated by an electrically insulating eventually penetrate the separator and electrically though ionically conducting liquid electrolyte supported connect the anode and cathode leading to a short on a porous separator to ensure the transfer of charge circuit of the cell. This spontaneous and uncontrolled carriers (lithium-ions) from one electrode to the other (7, event results in local heat evolution and – in the most 8). It appears noteworthy that the separator-electrolyte unfortunate case – thermal runaway of the cell (19, 20). system may also consist of a non-porous polymer layer, To circumvent this severe safety issue, in the 1970s i.e. a solid-state polymer electrolyte (SPE) membrane, several researchers developed the concept of lithium- occasionally swollen by a liquid electrolyte, i.e. a gel ion host structures, later commonly named insertion polymer electrolyte (GPE) (9). A deep understanding of compounds, thus avoiding the risk of superfi cial the chemical and electrochemical interactions of these (dendritic) lithium growth (21–24). In the course of components throughout the lifetime of a LIB is certainly these developments Scrosati and Lazzari proposed crucial to develop new concepts for advanced lithium- the ‘rocking chair battery’, which marked the fi rst based battery technologies in future (3). However, practical realisation of two host materials reversibly in a fi rst step each component of the cell has to be shuttling lithium-ions from the anode to the cathode addressed solely, keeping the other cell parameters upon discharge and vice versa upon charge (7, 8). constant. Nowadays, all commercially available secondary This article reviews the development of lithium- LIBs make use of this concept, although they employ ion anode materials (Section 2), focusing initially on different active materials as cathode and anode. those materials that were or are already employed Regarding the anode side, carbonaceous materials in commercial batteries (Section 3). Subsequently, are generally used as the lithium-ion host framework promising alternatives for these currently utilised (10, 11). The fi rst commercial secondary LIB, released anode materials are briefl y reviewed, in particular those by Sony Corporation in 1991, comprised LiCoO2 as materials storing lithium by a combined alloying and cathode and a soft carbon (more precisely coke; soft conversion mechanism (Section 4). Interdependencies carbons can be graphitised by thermal treatment of these lithium-ion anode materials and other cell at about 2300ºC) as an anode (Figure 1). This LIB components are also addressed. provided an energy density and specifi c energy of 200 Wh l–1 and 80 Wh kg–1, respectively, outperforming 2. The Development of Commercial Secondary all other battery technologies present in the market Lithium-Ion Batteries at that time. Moreover, this battery showed a highly reversible and stable cycling behaviour and an The most elementary anode material for lithium-based extremely high cell voltage of about 4 V, employing batteries is obviously metallic lithium, which has been propylene carbonate (PC) as electrolyte solvent used for primary (i.e. non-rechargeable) batteries (10, 15). The replacement of soft carbon by hard carbon since the early 1960s (10, 11). By possessing the (Figure 1) (i.e. non-graphitisable carbon), offering lowest standard potential (–3.05 V vs. a standard enhanced specifi c capacities, led to an increase of hydrogen electrode (SHE) (12)) and the lowest atomic the achievable volumetric and gravimetric energy weight (6.94 g mol–1; specifi c gravity: ρ= 0.53 g cm–3) density up to 295 Wh l–1 and 120 Wh kg–1, respectively among all metals, the utilisation of metallic lithium as (10, 15). The hard carbon anode facilitated the increase an anode offers the realisation of galvanostatic cells of the upper cut-off potential to 4.2 V, while presenting having an extremely high energy density (10, 13, 14). excellent cyclability in the – at that time – commonly Consequently, metallic lithium was also considered used PC-based electrolytes (10, 15). the candidate of choice for secondary lithium-based In summary, it can be stated that (by carefully batteries (10, 15, 16). However, lithium metal cells have controlling the heat treatment temperature) hard and one severe drawback, namely, inhomogeneous lithium soft carbons can be obtained, providing acceptable plating, which halted their commercial development specifi c capacities, low initial irreversible charge loss three decades ago. This uneven deposition of lithium and relatively low (dis-)charge hysteresis, enabling onto the anode surface upon charge results in the effi cient energy conversion and storage (25, 26). formation of so-called dendrites (11, 17, 18). These Nevertheless, the desired application of LIBs in cellular dendrites consist of high surface area, highly branched phones required the replacement of such anode

1.4 (a) 1.2 1.0 Li+ release 0.8 0.6 0.4 + Soft (disordered, graphitisable) 0.2 Li uptake 0 (b) 2.0 1.8

, V 1.6 + 1.4 Li+ release 1.2 . Li/Li

vs 1.0 0.8 0.6 0.4 Hard (disordered, non- Potential 0.2 Li+ uptake graphitisable) 0 (c) 1.4 1.2 1.0 0.8 Li+ release 0.6 0.4 Graphite 0.2 + 0 Li uptake 0 100 200 300 400 500 600 700 Speciﬁ c capacity, mAh g–1

Fig. 1. Schematic illustration (left side) of: (a) soft carbon; (b) hard carbon; and (c) graphite structures and (right side) their typical potential proﬁ les (Figure redrawn from (15, 16))

materials, as the voltage drop in the potential profi le lithium-ions at potentials below 0.5 V vs. Li/Li+ (Figure 1) of both carbonaceous materials (13) upon (dis-)charge (25, 28, 29). Additionally, it offers a signifi cantly higher (Figure 1) results in a substantially varying overall cell specifi c capacity of 372 mAh g–1 (corresponding to one voltage. However, cellular phones need an operational lithium per hexagonal carbon ring, i.e. LiC6) with limited voltage of at least 3 V (27). In addition, the utilisation of irreversible capacity (10, 13, 15). Graphite is composed these anode materials suffered a severe safety issue. of graphene layers, stacked in AB or ABC sequence and In order to achieve the maximum specifi c capacity, held together by van der Waals forces (13). Upon (dis-) the cathodic cut-off potential (i.e. the end-of-charge charge lithium-ions (de-)intercalate into the layered potential for the anode) must be set close to 0 V vs. Li/ structure by a so-called staging mechanism, resulting Li+ (16), thus, again posing the risk of metallic – in worst in an AA stacking confi guration once it is fully lithiated case dendritic – lithium plating on the carbon particles (25, 28, 29). Another great advantage of graphite is its surface. For these reasons a new anode material high electronic conductivity, originating from the sp2- was required. Graphite advantageously addresses all hybridisation (p-orbitals building a delocalised electron these issues rather satisfactorily and is thus still the network) of the carbon atoms located in the planar, most commonly employed anode material in today’s hexagonally structured graphene layers (13). commercial LIBs (5). A major obstacle for the implementation of graphite- based anodes, however, was their incompatibility with 3. State-of-the-art Lithium-Ion Battery Anode the standard electrolyte solvent PC (10, 15). In 1970, Materials Dey and Sullivan observed the electrochemically induced degradation of the graphite structure in 3.1. Graphite PC-based electrolytes (30). As reported in later studies, In contrast to soft and hard carbons, graphite shows the reason for this degradation was the co-intercalation a rather fl at potential profi le when reversibly hosting of solvent molecules, i.e. the solvation shell of the

36 © 2015 Johnson Matthey http://dx.doi.org/10.1595/205651314X685824 Johnson Matthey Technol. Rev., 2015, 59, (1) lithium-ions in the electrolyte, leading to a volume et al. (27) (and references cited therein), who provide a expansion of ~150% and subsequent exfoliation more detailed overview on this subject. of the single graphene layers (13). Furthermore, As mentioned earlier, graphite is still the most used lithium-ion intercalation occurs at potentials beyond anode material in commercial LIBs. However, as with the electrochemical stability window of common soft and hard carbons, it entails the inherent risk of electrolytes. Therefore, a continuous reductive metallic lithium plating, an intrinsically limited high decomposition of the electrolyte components takes rate capability upon charge and a very high reactivity place, leading to a drying-out of the cell and hence a towards the electrolyte in the lithiated state, which rapid capacity fading. The implementation of graphite might result in thermal runaway and occasionally the as lithium-ion anode was made possible, ﬁ nally, by event of a ﬁ re if the SEI gets damaged or decomposes replacing PC with mixtures of short-chain linear alkyl due to the overall temperature of the cell exceeding carbonates (low viscosity) and – most importantly – 130ºC (11, 17, 18, 33–37). ethylene carbonate (EC, high dielectric constant (28)). 3.2. Lithium Titanate, Li Ti O These solvents are also not stable (thermodynamically) 4 5 12 at such low potentials, but the initial decomposition of A very promising alternative for graphite is spinel-

EC results in the formation of a stable, electronically structured Li4Ti5O12 (LTO), which was fi rst reported in insulating, ionically conductive fi lm on the graphite 1994 (38). The reversible (de-)insertion of Li+ in the particles surface, preventing direct contact of the LTO framework occurs at a comparably high potential active material and the electrolyte while at the same (about 1.55 V vs. Li/Li+) and the theoretical specifi c time inhibiting the co-intercalation of solvent molecules capacity is relatively low (175 mAh g–1). Consequently, (Figure 2) (17, 18, 28, 29, 31, 32). Following an early the achievable energy density of a lithium-ion cell study by Peled, this protective surface fi lm is now employing LTO is much lower compared to graphite- known as the solid electrolyte interphase (SEI) (31). based cells (38–40). However, LTO exhibits several The replacement of hard carbon by graphite as great advantages compared to graphite, resulting in an anode led to a further jump in volumetric and steadily growing interest regarding its commercial gravimetric energy density up to 400 Wh l–1 and 165 Wh application (41–43). While the rather high operating kg–1, respectively (10, 15). As the theoretical capacity potential of LTO certainly restricts the overall energy of graphite has now been mostly achieved, recent density, it allows the realisation of inherently safer LIBs. research efforts to further improve the performance Since common electrolytes are thermodynamically of LIBs are basically dedicated to minimising the fi rst stable at 1.55 V vs. Li/Li+, no vigorous electrolyte cycle irreversible capacity, for instance by modifying decomposition occurs, thus avoiding issues related the graphite surface. An extensive description of these to the growth or breakdown of the SEI.The operating research activities is certainly beyond the scope of this potential is far from the region where metallic lithium review and the interested reader is referred to Bresser plates onto the anode surface and consequently no dendritic formation can occur (34, 38, 39, 42, 44). In addition, the negligible volume expansion (39, 45) of LTO upon (de-)lithiation results in an outstanding cycling stability for more than tens of thousands of fast Activation barrier (dis-)charge cycles (46, 47). As apparent from Figure 3, LTO exhibits a desirable fl at potential profi le corresponding to a two-phase (spinel to rock-salt) electrochemical lithium (de-) insertion process (48):

+ – Graphite SEI Electrolyte Li4Ti5O12 + 3 Li + 3 e  Li7Ti5O12 Fig. 2. Schematic illustration of the SEI on graphite, The insulating character (49) of spinel phase LTO, emphasising its role in the desolvation process of lithium however, is a major obstacle for fast (de-)lithiation ions prior to the intercalation of lithium into the graphite host processes. Hence, several strategies were pursued material (Reproduced with permission from (32). Copyright to improve its electronic conductivity. Inter alia, 2009 American Chemical Society) nanostructuring of the LTO particles leading to shorter

initial lithiation, in a partially irreversible step, Li2O and 2.0 metallic Sn are formed, followed by a reversible alloying reaction of lithium and tin (61). It was assumed that the

, V + + Li deinsertion electrochemically inert ‘matrix’ of Li2O separating the initially formed tin nanograins would prevent the latter . Li/Li 1.5 Li+ insertion from aggregation upon cycling (62, 63), but not least vs due to the substantial volume expansion of ~200% (56) accompanying the alloying reaction, the comprised tin

Potential still aggregates upon long-term cycling (64, 65). This 1.0 leads to rather rapid capacity fading after several Specifi c capacity, mAh g–1 cycles. Therefore, research efforts were focused on creating Fig. 3. Typical potential profi le for a LTO electrode showing secondary particle structures or matrices which are a fl at Li+ (de-)insertion plateau and a low voltage hysteresis capable of buffering this volume expansion/contraction (Image courtesy of Guk Tae Kim, Helmholtz Institute Ulm stress. Such research efforts comprised inter alia (HIU), Ulm, Germany) the preparation of hollow carbon nanospheres (66), core-shell nanostructures (67–69) and submicron- or micron-sized carbonaceous matrices (70–73). diffusion pathways for lithium-ions and electrons and an Despite these very promising approaches, to date only increased electrode/electrolyte contact area resulted one tin-based alloying material – a composite of tin, in a remarkable enhancement of its electrochemical cobalt and carbon – has been successfully employed performance, particularly at high (dis-)charge rates in commercial LIBs (56, 74). It is reported that upon (14, 44, 47, 50). Further improvement was achieved lithiation this Sn-Co-C composite initially forms a by coating the (nanosized) particles with conductive Li-Sn-Co phase, which subsequently separates into a surface layers (e.g. carbon) or by introducing LTO Li-Sn alloy (75) and amorphous cobalt, provided that in highly conductive mesoporous (carbonaceous) a suffi cient amount of cobalt is present in the initial matrices (48, 50–52). As a result, LTO appears highly composite (76). Upon discharge, the delithiated tin attractive for the realisation of substantially safer, high alloys with the amorphous cobalt. This rather complex power LIBs (5, 45, 53). mechanism is supposedly the origin of the improved cycle life compared to pure Sn- or SnO -based anodes 3.3. Alloying Materials 2 (77–80). Several elements (e.g. Sn, Pb, Al, Sb, Zn, Si) are able It may be noted that very recently silicon-based anodes to reversibly form alloys with lithium at low potential (more precisely, carbon-coated silicon nanostructures) (54, 55). In contrast to the already discussed lithium were commercialised, promising substantially higher storage by intercalation and insertion, the alloying specifi c energies (81, 82) compared to pure graphite mechanism is fundamentally different, giving rise or graphite-based anodes containing a relatively low to multiple new issues. However, with appealing content of silicon (83). theoretical specifi c capacities (exceeding that of graphite up to tenfold) and hence, energy densities, 4. Anode Materials for Next-generation Lithium- alloying anodic materials are currently intensely Ion Batteries researched (56–58). Clearly, one of the major issues regarding alloying materials in general is the large Research activities for the next generation of lithium- volume expansion/contraction upon (de-)lithiation, ion anodes are now focusing on the development of leading to the fracturing of active material particles, the materials capable of surpassing graphite anodes in subsequent loss of electronic contact and fi nally the terms of energy, power and safety, while maintaining (if pulverization of the electrode (57, 59). not improving) the level of environmental friendliness More than ten years ago an amorphous tin-oxygen- and raw material availability. Presently, nanosized based composite was developed by Fuji Photo alternative active materials (5, 84, 85) reversibly hosting Film Corporation (60). However, it has never been lithium by both mechanisms discussed so far, insertion successfully commercialised for various reasons. Upon (e.g. N-doped carbonaceous materials or titanium

38 © 2015 Johnson Matthey http://dx.doi.org/10.1595/205651314X685824 Johnson Matthey Technol. Rev., 2015, 59, (1) dioxide) as well as alloying (e.g. silicon or silicon from enhanced electron and lithium-ion transport oxide), are attracting world-wide scientifi c interest (27) due to shorter diffusion (or more generally transport) and several excellent reviews are available for these pathways and reduced internal stress during volume very promising anode materials (44, 84, 86, 87). expansion/contraction upon (de-)lithiation (56). For In this review we focus on the latest upcoming a more detailed insight into the (dis)advantages research area characterised by a completely different arising from using nanostructured materials for LIB lithium storage mechanism: chemical displacement or applications the interested reader is referred to Bruce so-called conversion reactions. et al. (84), Scrosati et al. (74), Lee and Cho (87), and more recently Bresser et al. (91). Defi nitely, the most 4.1. Conversion Materials appealing feature of conversion materials is their ability Initially, displacement (i.e. conversion) reactions were to store more equivalents of lithium (two to eight per considered to be irreversible at room temperature due unit formula of the starting material) than any insertion to the extensive energy demand for bond breakage, compound (up to two), resulting in substantially higher atomic reorganisation, and the formation of new bonds specifi c capacities as displayed in Table I (3, 14). (24). In 2000, Poizot et al. (86) reported for the fi rst time However, conversion materials exhibit a series of reversible lithium storage using transition metal oxides severe drawbacks which necessarily need to be as active materials, providing specifi c capacities of overcome before they can be seriously considered for more than 700 mAh g–1. Since then a growing interest commercial applications (89). The conversion reaction in battery materials following a conversion mechanism inherently causes a massive structural reorganisation, (Figure 4) (88) can be noted, including transition metal which potentially leads to a loss of electrical contact oxides, sulfi des, nitrides, phosphides, fl uorides and and electrode pulverisation (89). Moreover, conversion other phases (89). The conversion mechanism can be materials suffer from a very high reactivity towards generally described as follows (85): commonly used electrolytes and a marked (dis-)charge voltage hysteresis, considerably affecting the energy TM A + z e– + z Li+ x TM0 + Li A x y z y storage effi ciency of such electrodes (14, 89, 92). The Upon lithiation the transition metal (TM) is reduced to elevated operational potentials of many conversion its metallic state and embedded in the simultaneously materials also limit the achievable energy density (14, formed lithium-comprising compound LizAy (where A 56) and the large fi rst-cycle irreversible capacity is stands for O, N, P, F and others). Due to the inherent unacceptable for practical applications and requires physico-chemical properties of the initially formed TM special electrode treatments for compensation (56, nanograins, the formation of LizAy becomes reversible 89). Taking into account the surface area which is (86). It might be noted that very recently also the frequently high (an intrinsic feature of nanostructured reversible formation of lithium silicate, starting from particles) and, as already mentioned, reactive, as cobalt silicate, was reported (90). Nevertheless, despite well as the SEI instability known from compounds the growing knowledge about nanosized materials there is still a lack of fundamental understanding of the Table I Comparison of Theoretical Specifi c processes occurring in conversion materials, boosting Capacities of Selected Insertion and the scientifi c interest regarding this class of materials Conversion Materialsa (56). Commonly, nanostructured materials benefi t Material Theoretical Anode material type capacity, mAh g–1 Soft carbons 200–1000 8 Li+ + 8e– Hard carbons 200–600 Insertion Graphite 300–375 Co3O4 AAmorphousmorphous Nanosized Co0 LTO 175 LLii O mmatrixatrix (diameter 2–3 nm) 2 TiO2 330 Metal oxides 500–1200 Fig. 4. Schematic illustration of the conversion mechanism Conversion Metal phosphides, shown exemplarily for spinel cobalt oxide (Figure redrawn 500–1800 from (88)) sulfi des or nitrides aTable prepared according to (13, 85)

39 © 2015 Johnson Matthey http://dx.doi.org/10.1595/205651314X685824 Johnson Matthey Technol. Rev., 2015, 59, (1) experiencing considerable volume changes (56, 86), further enhanced the electrochemical performance, conversion materials have just reached the early stage preventing the electrode morphology upon cycling of development. For a detailed summary concerning the (94), while the choice of the carbon precursor obviously different types of conversion materials the interested also had a great impact on the cycling stability (103). reader is referred to Cabana et al. (89), Nitta and After investigating the reaction kinetics of the involved Yushin (56) or Goriparti et al. (85). electrochemical mechanisms of the carbon-coated ZnFe O (94), very recently Varzi et al. (104) were able 4.2. Conversion-Alloying Materials 2 4 to realise a high-power LIB, comprising carbon-coated

Conversion-alloying materials mark another step ZnFe2O4 nanoparticles as an anode and a composite of forward in developing high energy and high power LiFePO4 and multiwalled carbon nanotubes as cathode lithium-ion anode materials. The idea behind this new (Figure 5). This lithium-ion full-cell retained 85% of its class of active materials is to further increase the initial capacity after 10,000 cycles at a current rate uptake of lithium per unit formula of starting material as high as 10 C with respect to the (capacity-limiting) by using mixed metal oxides in which one of the cathode or about 3 C in regard to the ZnFe2O4-C comprised metals can further alloy with lithium after anode. To compensate the high fi rst-cycle irreversible being initially reduced to the metallic state (93, 94). capacity Varzi et al. investigated different degrees of This obviously results in higher specifi c capacities than partial pre-lithiation of the anode. Remarkably, even the theoretically achievable for ‘pure’ conversion materials. most extensive lithium doping (600 mAh g–1) did not Exploiting, for instance, the lithium alloying capability signifi cantly affect the rate performance of the carbon- of zinc, iron is partially substituted by zinc in the coated ZnFe2O4 nanoparticles, while at the same time commonly known conversion material Fe3O4, giving the degree of pre-lithiation allowed the overall voltage e.g. ZnFe2O4. Upon lithiation metallic zinc and iron of the lithium-ion full-cell to be tailored (104). These are formed. Subsequently, zinc can further reversibly promising results confi rm that the concept of using alloy with lithium. Overall, nine equivalents of lithium conversion or preferably conversion-alloying high per unit formula can be stored in ZnFe2O4 (theoretical capacity anodes – despite the manifold issues these specifi c capacity: 1000.5 mAh g–1) compared to only materials are facing – is a valuable approach to future eight equivalents of lithium per unit formula in Fe3O4 challenges for LIBs. (926 mAh g–1) (94). Analogously to other conversion materials, the chemical reaction of spinel-structured zinc ferrite 140 100 Coulombic ef and lithium, fi rst reported in 1986 (95), was initially –1 120 considered to be irreversible. Nevertheless, after 80 100 conclusive proof of reversible lithium uptake in 60 80 ZnFe O thin fi lms in 2004 (96), research efforts were 2 4 fi ciency,% focused on achieving high reversibility and increased 60 40

c capacity, mAh g c capacity, Effi ciency specifi c capacities. Early studies nonetheless obtained fi 40 Charge 20 neither stable cycling performance nor the material’s 20 Discharge theoretical capacity. Additionally, the rate performance, Speci 0 0 i.e. the achievable specifi c capacity at elevated specifi c 0 2500 5000 7500 10,000 Cycles currents, remained a severe issue (97–101). The apparently inevitable capacity fading was attributed to Fig. 5. Long-term cycling stability of a ZFO-C/LFP-CNT full-cell, applying a high current density (3 mA cm–2) (Image the formation of an insulating polymeric layer related courtesy of Alberto Varzi, Helmholtz Institute Ulm (HIU), to an ongoing electrolyte decomposition (44) and/or Ulm, Germany) signifi cant volume changes upon (de-)lithiation (98). Transferring their knowledge about electronically conductive carbonaceous percolating networks 5. Conclusions (102) to conversion-alloying materials, Bresser et al. (94) very recently succeeded in overcoming these This brief overview of commercial secondary LIB issues by coating ZnFe2O4 nanoparticles with an anodes refl ects only partially the intensive and amorphous carbon layer. The use of rather stiff sodium- continuously growing research efforts carried out carboxymethyl cellulose (CMC; water-based) as binder within the past 25 years in this specifi c segment of

LIB technology. It is also evident as the strict industrial 13. M. Winter, J. O. Besenhard, M. E. Spahr and P. Novák, requirements have so far allowed only a few materials Adv. Mater., 1998, 10, (10), 725 to reach a commercial level, for which the guarantee of 14. M. Armand and J.-M. Tarascon, Nature, 2008, 451, reliable performance is doubtlessly the most important (7179), 652 requirement. As this article shows, even the change 15. Y. Nishi, Chem. Rec., 2001, 1, (5), 406 of basic reaction mechanisms from intercalation/ 16. Handbook of Battery Materials, ed. J. O. Besenhard, insertion to alloying and conversion has not yet led to Wiley-VCH Verlag GmbH, Weinheim, Germany, 1999 a breakthrough in LIB technology. We still do not have 17. S. Flandrois and B. Simon, Carbon, 1999, 37, (2), 165 satisfactory solutions for the challenges within sight, but 18. R. Yazami, Electrochim. Acta, 1999, 45, (1–2), 87 the encouraging advances and manifold developments 19. K. Brandt, Solid State Ionics, 1994, 69, (3–4), 173 of anode materials (and LIBs in general) from the ﬁ rst commercial device up to the present ones provide a 20. U. von Sacken, E. Nodwell, A. Sundler and J. R. Dahn, Solid State Ionics, 1994, 69, (3–4), 284 solid basis for exploring the next generation of LIBs. 21. B. M. L. Rao, R. W. Francis and H. A. Christopher, J. Acknowledgements Electrochem. Soc., 1977, 124, (10), 1490 The authors would like to thank Dr Guk Tae Kim, 22. D. W. Murphy, F. J. Di Salvo, J. N. Carides and J. V. Helmholtz Institute Ulm (HIU), Ulm, Germany, for Waszczak, Mater. Res. Bull., 1978, 13, (12), 1395 providing the potential proﬁ le of LTO (Figure 3) and 23. D. W. Murphy and J. N. Carides, J. Electrochem. Soc., Dr Alberto Varzi, Helmholtz Institute Ulm (HIU), Ulm, 1979, 126, (3), 349 Germany, for providing the cycling data of ZFOC/LFP- 24. D. W. Murphy and P. A. Christian, Science, 1979, 205, CNT full-cells (Figure 5). (4407), 651 25. J. R. Dahn, T. Zheng, Y. Liu and J. S. Xue, Science, 1995, 270, (5236), 590 References 26. T. Zheng, W. R. McKinnon and J. R. Dahn, J. 1. “Handbook of Batteries”, 3rd Edn., eds. D. Linden and Electrochem. Soc., 1996, 143, (7), 2137 T. B. Reddy, McGraw-Hill, New York, USA, 2002 27. D. Bresser, E. Paillard and S. Passerini, in “Advances 2. J. O. Besenhard and M. Winter, ChemPhysChem, in Batteries for Medium and Large -scale Energy 2002, 3, (2), 155 Storage”, eds. C. Menictas, M. Skyllas-Kazacos and T. 3. B. Scrosati and J. Garche, J. Power Sources, 2010, M. Lim, Woodhead Publishing, Cambridge, UK, 2014, 195, (9), 2419 Chapters 6 & 7 4. R. Marom, S. F. Amalraj, N. Leifer, D. Jacob and D. 28. R. Fong, U. von Sacken and J. R. Dahn, J. Electrochem. Aurbach, J. Mater. Chem., 2011, 21, (27), 9938 Soc., 1990, 137, (7), 2009 5. K. Zaghib, A. Mauger, H. Groult, J. B. Goodenough 29. D. Aurbach, Y. Ein-Eli, O. Chusid (Youngman), Y. and C. M. Julien, Materials, 2013, 6, (3), 1028 Carmeli, M. Babai and H. Yamin, J. Electrochem. 6. M. M. Thackeray, C. Wolverton and E. D. Isaacs, Soc., 1994, 141, (3), 603 Energy Environ. Sci., 2012, 5, (7), 7854 30. A. N. Dey and B. P. Sullivan, J. Electrochem. Soc., 7. B. Scrosati, J. Electrochem. Soc., 1992, 139, (10), 1970, 117, (2), 222 2776 31. E. Peled, J. Electrochem. Soc., 1979, 126, (12), 2047 8. M. Lazzari and B. Scrosati, J. Electrochem. Soc., 32. Y. Yamada, Y. Iriyama, T. Abe and Z. Ogumi, Langmuir, 1980, 127, (3), 773 2009, 25, (21), 12766 9. P. Arora and Z. (J.) Zhang, Chem. Rev., 2004, 104, 33. J. i. Yamaki, H. Takatsuji, T. Kawamura and M. (10), 4419 Egashira, Solid State Ionics, 2002, 148, (3–4), 241 10. Y. Nishi, J. Power Sources, 2001, 100, (1–2), 101 34. J. Jiang, J. Chen and J. R. Dahn, J. Electrochem. 11. J.-M. Tarascon and M. Armand, Nature, 2001, 414, Soc., 2004, 151, (12), A2082 (6861), 359 35. Q. Wang, J. Sun, X. Yao and C. Chen, J. Electrochem. 12. D. R. Lide, “Handbook of Chemistry and Physics”, Soc., 2006, 153, (2), A329 95th Edn., CRC Press, Taylor & Francis Group, Boca 36. K. Zhao, M. Pharr, J. J. Vlassak and Z. Suo, J. Appl. Raton, USA, 2014 Phys., 2010, 108, (7), 073517

37. S. Renganathan, G. Sikha, S. Santhanagopalan 56. N. Nitta and G. Yushin, Part. Part. Syst. Charact., and R. E. White, J. Electrochem. Soc., 2010, 157, 2014, 31, (3), 317 (2), A155 57. D. Larcher, S. Beattie, M. Morcrette, K. Edström, J.-C. 38. E. Ferg, R. J. Gummow, A. de Kock and Jumas and J.-M. Tarascon, J. Mater. Chem., 2007, 17, M. M. Thackeray, J. Electrochem. Soc., 1994, 141, (36), 3759 (11), L147 58. C.-M. Park, J.-H. Kim, H. Kim and H.-J. Sohn, Chem. 39. T. Ohzuku, A. Ueda and N. Yamamota, J. Electrochem. Soc. Rev., 2010, 39, (8), 3115 Soc., 1995, 142, (5), 1431 59. J. O. Besenhard, M. Hess and P. Komenda, Solid 40. M. M. Thackeray, ‘Lithiated Oxides for Lithium-Ion State Ionics, 1990, 40–41, (2), 525 Batteries’, in Rechargeable Lithium and Lithium- 60. Y. Idota, T. Kubota, A. Matsufuji, Y. Maekawa and T. Ion Batteries, 186th Meeting of the Electrochemical Miyasaka, Science, 1997, 276, (5317), 1395 Society, Miami Beach, Florida, USA, 9th–14th October, 61. R. A. Huggins, Solid State Ionics, 1998, 113–115, 57 1994, The Electrochemical Society Proceedings Series, ECS, Pennington, New Jersey, USA, 1995 62. J. Y. Huang, L. Zhong, C. M. Wang, J. P. Sullivan, W. Xu, L. Q. Zhang, S. X. Mao, N. S. Hudak, X. H. Liu, 41. K. Amine, I. Belharouak, Z. Chen, T. Tran, H. Yumoto, A. Subramanian, H. Fan, L. Qi, A. Kushima and J. Li, N. Ota, S.-T. Myung and Y.-K. Sun, Adv. Mater., 2010, Science, 2010, 330, (6010), 1515 22, (28), 3052 63. C.-M. Wang, W. Xu, J. Liu, J.-G. Zhang, L. V. Saraf, B. 42. I. Belharouak, G. M. Koenig, Jr., and K. Amine, J. W. Arey, D. Choi, Z.-G. Yang, J. Xiao, S. Thevuthasan Power Sources, 2011, 196, (23), 10344 and D. R. Baer, Nano Lett., 2011, 11, (5), 1874 43. Z. Chen, I. Belharouak, Y.-K. Sun and K. Amine, Adv. Funct. Mater., 2013, 23, (8), 959 64. I. A. Courtney and J. R. Dahn, J. Electrochem. Soc., 1997, 144, (6), 2045 44. A. S. Aricò, P. Bruce, B. Scrosati, J.-M. Tarascon and W. van Schalkwijk, Nature Mater., 2005, 4, (5), 366 65. C. Kim, M. Noh, M. Choi, J. Cho and B. Park, Chem. Mater., 2005, 17, (12), 3297 45. M. Wagemaker, D. R. Simon, E. M. Kelder, J. Schoonman, C. Ringpfeil, U. Haake, D. Lützenkirchen- 66. W.-M. Zhang, J.-S. Hu, Y.-G. Guo, S.-F. Zheng, L.-S. Hecht, R. Frahm and F. M. Mulder, Adv. Mater., 2006, Zhong, W.-G. Song and L.-J. Wan, Adv. Mater., 2008, 18, (23), 3169 20, (6), 1160 46. K. Zaghib, M. Simoneau, M. Armand and M. Gauthier, 67. T. Prem Kumar, R. Ramesh, Y. Y. Lin and G. T.-K. Fey, J. Power Sources, 1999, 81–82, 300 Electrochem. Commun., 2004, 6, (6), 520 47. D. Bresser, E. Paillard, M. Copley, P. Bishop, M. Winter 68. Y. Qiu, K. Yan and S. Yang, Chem. Commun., 2010, and S. Passerini, J. Power Sources, 2012, 219, 217 46, (44), 8359 48. L. Cheng, J. Yan, G.-N. Zhu, J.-Y. Luo, C.-X. Wang 69. Y. Yu, L. Gu, C. Wang, A. Dhanabalan, P. A. van Aken and Y.-Y. Xia, J. Mater. Chem., 2010, 20, (3), 595 and J. Maier, Angew. Chem. Int. Ed., 2009, 48, (35), 6485 49. C. H. Chen, J. T. Vaughey, A. N. Jansen, D. W. Dees, A. J. Kahaian, T. Goacher and M. M. Thackeray, J. 70. G. Derrien, J. Hassoun, S. Panero and B. Scrosati, Electrochem. Soc., 2001, 148, (1), A102 Adv. Mater., 2007, 19, (17), 2336 50. E. Kang, Y. S. Jung, G.-H. Kim, J. Chun, U. Wiesner, 71. Y. Xu, Q. Liu, Y. Zhu, Y. Liu, A. Langrock, M. R. A. C. Dillon, J. K. Kim and J. Lee, Adv. Funct. Mater., Zachariah and C. Wang, Nano Lett., 2013, 13, (2), 470 2011, 21, (22), 4349 72. J. Hassoun, G. Derrien, S. Panero and B. Scrosati, 51. L. Zhao, Y.-S. Hu, H. Li, Z. Wang and L. Chen, Adv. Adv. Mater., 2008, 20, (16), 3169 Mater., 2011, 23, (11), 1385 73. D. Bresser, F. Mueller, D. Buchholz, E. Paillard and S. 52. H.-G. Jung, S.-T. Myung, C. S. Yoon, S.-B. Son, K. Passerini, Electrochim. Acta, 2014, 128, 163 H. Oh, K. Amine, B. Scrosati and Y.-K. Sun, Energy 74. B. Scrosati, J. Hassoun and Y.-K. Sun, Energy Environ. Environ. Sci., 2011, 4, (4), 1345 Sci., 2011, 4, (9), 3287 53. S. Scharner, W. Weppner and P. Schmid-Beurmann, 75. J.-j. Zhang and Y.-y. Xia, J. Electrochem. Soc., 2006, J. Electrochem. Soc., 1999, 146, (3), 857 153, (8), A1466 54. A. N. Dey, J. Electrochem. Soc., 1971, 118, (10), 1547 76. N. Tamura, Y. Kato, A. Mikami, M. Kamino, S. Matsuta 55. J. Wang, P. King and R. A. Huggins, Solid State Ionics, and S. Fujitani, J. Electrochem. Soc., 2006, 153, (8), 1986, 20, (3), 185 A1626

77. Q. Fan, P. J. Chupas and M. S. Whittingham, 91. D. Bresser, E. Paillard, P. Niehoff, S. Krueger, F. Electrochem. Solid-State Lett., 2007, 10, (12), A274 Mueller, M. Winter and S. Passerini, ChemPhysChem, 78. J. Hassoun, S. Panero, G. Mulas and B. Scrosati, J. 2014, 15, (10), 2177 Power Sources, 2007, 171, (2), 928 92. M. R. Palacín, Chem. Soc. Rev., 2009, 38, (9), 2565 79. J. Hassoun, G. Mulas, S. Panero and B. Scrosati, 93. D. Bresser, F. Mueller, M. Fiedler, S. Krueger, R. Electrochem. Commun., 2007, 9, (8), 2075 Kloepsch, D. Baither, M. Winter, E. Paillard and S. 80. C. M. Ionica-Bousquet, P. E. Lippens, L. Aldon, J. Passerini, Chem. Mater., 2013, 25, (24), 4977 Olivier-Fourcade and J. C. Jumas, Chem. Mater., 94. D. Bresser, E. Paillard, R. Kloepsch, S. Krueger, M. 2006, 18, (26), 6442 Fiedler, R. Schmitz, D. Baither, M. Winter and S. 80. ‘Amprius raises $30M to Accelerate Commercialization Passerini, Adv. Energy Mater., 2013, 3, (4), 513 of High Energy Batteries’, Amprius Inc, 6th January, 95. C. J. Chen, M. Greenblatt and J. V. Waszczak, Solid 2014 State Ionics, 1986, 18–19, (2), 838 81. K. Bullis, ‘Startup gets $30 Million to Bring High- 96. Y.-N. NuLi, Y.-Q. Chu and Q.-Z. Qin, J. Electrochem. Energy Silicon Batteries to Market’, MIT Technology Soc., 2004, 151, (7), A1077 Review, 10th January, 2014 97. Y. Sharma, N. Sharma, G. V. Subba Rao and B. V. R. 83. C.-H. Yim, F. M. Courtel and Y. Abu-Lebdeh, J. Mater. Chowdari, Solid State Ionics, 2008, 179, (15–16), 587 Chem. A, 2013, 1, (28), 8234 98. X. Guo, X. Lu, X. Fang, Y. Mao, Z. Wang, L. Chen, 84. P. G. Bruce, B. Scrosati and J.-M. Tarascon, Angew. X. Xu, H. Yang and Y. Liu, Electrochem. Commun., Chem. Int. Ed., 2008, 47, (16), 2930 2010, 12, (6), 847 85. S. Goriparti, E. Miele, F. De Angelis, E. Di Fabrizio, R. 99. M. A. Woo, T. W. Kim, I. Y. Kim and S.-J. Hwang, Solid Proietti Zaccaria and C. Capiglia, J. Power Sources, State Ionics, 2011, 182, (1), 91 2014, 257, 421 100. Y. Deng, Q. Zhang, S. Tang, L. Zhang, S. Deng, Z. 86. P. Poizot, S. Laruelle, S. Grugeon, L. Dupont and J.-M. Shi and G. Chen, Chem. Commun., 2011, 47, (24), Tarascon, Nature, 2000, 407, (6803), 496 6828 87. K. T. Lee and J. Cho, Nano Today, 2011, 6, (1), 28 101. P. F. Teh, Y. Sharma, S. S. Pramana and M. Srinivasan, 88. J.-M. Tarascon, S. Grugeon, M. Morcrette, S. Laruelle, J. Mater. Chem., 2011, 21, (38), 14999 P. Rozier and P. Poizot, Comptes Rendus Chim., 102. D. Bresser, E. Paillard, E. Binetti, S. Krueger, M. 2005, 8, (1), 9 Striccoli, M. Winter and S. Passerini, J. Power 89. J. Cabana, L. Monconduit, D. Larcher and M. R. Sources, 2012, 206, 301 Palacín, Adv. Mater., 2010, 22, (35), E170 103. F. Mueller, D. Bresser, E. Paillard, M. Winter and S. 90. F. Mueller, D. Bresser, N. Minderjahn, J. Kalhoff, S. Passerini, J. Power Sources, 2013, 236, 87 Menne, S. Krueger, M. Winter and S. Passerini, Dalton 104. A. Varzi, D. Bresser, J. von Zamory, F. Müller and S. Trans., 2014, 43, (40), 15013 Passerini, Adv. Energy Mater., 2014, 4, (10), 1400054

The Authors

Nicholas Loefﬂ er is a second year PhD student in the group of Professor Stefano Passerini, formerly at the Institute of Physical Chemistry & MEET Battery Research Centre at the University of Münster, Germany, now working at the Helmholtz Institute Ulm (HIU) of the Karlsruhe Institute of Technology (KIT), Germany. His main research activities are focused on the processing of electrode formulations in aqueous media as well as investigation of suitable binder systems and additives and their inﬂ uence on the electrochemical performance of lithium-ion batteries.

Dominic Bresser is a third year PhD student in the group of Professor Stefano Passerini, formerly at the Institute of Physical Chemistry & MEET Battery Research Centre at the University of Münster, now working at the Helmholtz Institute Ulm (HIU) of the Karlsruhe Institute of Technology (KIT). His main research activities are focused on the development and investigation of nanostructured materials for lithium and lithium-ion batteries as well as the design and study of carbonaceous coatings and matrices and its inﬂ uence on the electrochemical performance of nanosized active materials.

Stefano Passerini has been a Professor at the Karlsruhe Institute of Technology (KIT) since 2014, carrying out his activities in the Helmholtz Institute Ulm (HIU), the joint research facility of KIT, University of Ulm, Germany, the German Aerospace Center (DLR), and the Centre for Solar Energy and Hydrogen Research (ZSW). Before then, he co-founded the MEET Battery Research Center at the University of Münster, Germany. His research activities are focused on electrochemical energy storage in batteries and supercapacitors. He is (co-)author of more than 250 scientiﬁ c papers, a few book chapters, and several international patents. In 2012, he was awarded the Research Award of the Electrochemical Society Battery Division. Since 2013 he has been appointed as European Editor of Journal of Power Sources.

Mark Copley is a Principal Scientist at the Johnson Matthey Technology Centre, Sonning Common, UK. His work focuses on the development of nanomaterials for use as active electrode materials in lithium-ion secondary batteries. He gained his PhD (2006), under the supervision on Professor Trevor Spalding University College Cork, Ireland. The thesis focused on the development of ordered mesoporous structures, their tunable synthesis and applications in catalysis.

10th International Congress on Membrane and Membrane Processes

Advances in gas and liquid separation plus latest innovations in membrane materials

Reviewed by Xavier (Xian-Yang) Quek Johnson Matthey Technology Centre, Blounts Court, Plenary Lectures Sonning Common, Reading, RG4 9NH, UK William J. Koros Membrane Technology (Georgia Institute of Pathways to Low Email: [email protected] Technology, USA) Energy Intensive Large Scale Gas Separations

1. Introduction Yiqun Fan (Nanjing Inorganic Membranes University of for Sustainable Industry Jointly organised by the Aseanian Membrane Society, Technology, China) Processes the European Membrane Society and the North American Membrane Society, the 10th International Tai-Shung Chung Polymeric Membranes Congress on Membrane and Membrane Processes (National University for Clean Water (ICOM) was held at Suzhou, China from 20th to of Singapore, Production and 25th July 2014. ICOM is a highly regarded triennial Singapore) Osmotic Power conference in the membrane community, attracting Generation scientists from around the world for scientiﬁ c dissemination and discussion on membranes. The Matthias Wessling Geometry Matters 10th ICOM attracted approximately 1300 delegates (Rheinisch representing 39 countries. The programme consists Westfälische of four plenary lectures, 86 keynote lectures, 424 oral Technische presentations (split into nine parallel sessions) and Hochschule (RWTH) 662 poster presentations. With such a vast selection Aachen University, of presentations, only selected highlights on themes Germany) related to gas separation, liquid separation, polymeric membranes, inorganic membranes and novel membrane processes and applications are discussed plenary lecture: in this review. • Gas fluxes (flow rate per unit area) across Further information on the 10th ICOM can be found polymeric membranes are two orders of on the conference website (1). magnitude lower than liquid fluxes • Trade-off relationship between flux and 2. Gas Separation selectivity is much higher for gas than liquid separation The following challenges in applying membranes to • Kinetic diameter differences between molecules large scale separations were highlighted by William in gas separation are much smaller than for Koros (Georgia Institute of Technology, USA) in his liquid separation.

This section on gas separation will cover carbon dedicated to engineering studies on membrane dioxide removal, paraffi n/olefi n separation and processes. hydrocarbon separation. A series of presentations by Membrane Technology and Research, Inc (MTR) on post-combustion carbon 2.1 Carbon Dioxide Separation capture demonstrated the importance of understanding A key observation from this conference is that there has the processes in order to better utilise the membranes. been an increase in the use of carbon molecular sieves Richard Baker (MTR, USA) emphasised the importance and membrane contactors for CO2 removal (in both of pressure ratio. Through their studies, the typical natural gas purifi cation and carbon capture). In addition, economical pressure ratio range is about 5 to 10. there were several lectures which emphasised the Pingjiao Hao (MTR, USA) showed that combining a need for better understanding of the use of membranes conventional CO2 separation membrane with a gas/gas in a process. membrane contactor (Figure 1(a)) (2) is more effective

Under high CO2 partial pressure and in the presence for carbon capture than a standalone membrane unit. of hydrogen sulfi de (H2S) in the stream, polymeric Xiaotong Wei (MTR, USA) showed that carbon capture membranes are known to swell, causing deteriorated from a natural gas power plant is more complex than separation performance. Koros showed in his plenary from a coal power plant (Figure 1(b)) (3). This is due lecture that cross-linking of polymeric membranes is to signifi cantly lower CO2 concentration in the fl ue gas effective in stabilising the membranes and preventing being emitted from a natural gas plant. swelling. However further improvements in membrane Numerous other presentations have also emphasised performance can only be achieved using membranes the importance of using process engineering tools with molecular sieving abilities such as carbon to understand membrane processes at very different molecular sieves (CMS). The performance of a CMS scales. Eric Favre (Université de Lorraine, France) membrane was shown to exceed the present upper used process engineering tools to design membrane bound of Robeson’s trade-off graph. processes and evaluate their economic benefi ts in Membrane contactors, which combine the advantages carbon capture. Maria Grätz (Helmholtz-Zentrum of membrane technology and solvent absorption, are Geesthacht, Germany) used simulations to investigate a promising technology for CO2 removal. Shiguang Li the effects of various process parameters for pre- (Gas Technology Institute (GTI), USA) presented on combustion carbon capture using membranes. Iran a pilot scale study for post-combustion CO2 capture Chary-Prada (Saudi Aramco, Saudi Arabia) investigated using poly(ether ether ketone) (PEEK) hollow fi bre the confi gurations and economics for two- and three- membrane contactors. The membrane contactor GTI stage membrane processes used for bulk acid gas is developing can be used in both the absorber and removal from natural gas. the desorber section. Laboratory testing has found that 2.2 Paraffi n/Olefi n Separation the performance of the PEEK membrane contactor is not affected by impurities such as oxygen or oxides of Separation of paraffi n/olefi n mixtures is one of the most sulfur (SOx) and nitrogen (NOx). Initial pilot studies challenging processes due to the small differences in were carried out using a slip stream from Joliet power the kinetic diameter. Several reports demonstrated station and future tests will be conducted at the National promising progress in the separation of paraffi n/olefi n Carbon Capture Centre. mixtures using inorganic membranes and facilitated Christophe Castel (Université de Lorraine, France) transport membranes. used a fl ue gas slip stream from one of Compagnie William Koros showed that polymer derived CMS Parisienne de Chauffage Urbain (CPCU)’s power membranes are effective for paraffi n/olefi n separation. The plants as a feed to their membrane contactor. membrane was proposed to be used for debottlenecking Commercially available polytetrafl uoroethylene (PTFE) of existing distillation processes. Thinner CMS selective hollow fi bre membrane from PolyMem and 30% layers can increase the fl ux of propylene through the monoethanolamine (MEA) solution was used in their membrane. Jerry Lin (Arizona State University, USA) has membrane contactor. Their pilot study is still at a very shown that thinner CMS membranes were prepared by early phase in comparison to GTI’s work. coating the surface of α-Al2O3 support with -Al2O3. The Emphasis on understanding membrane processes smaller pores of -Al2O3 allow a thinner defect-free CMS was refl ected by a signifi cant number of presentations layer to be prepared.

(a) (b) CO2 purge Nitrogen purge Air + CO2 Selective 70–80% CO2 2% CO2 recycle CO Natural 2 membrane Blower capture Air gas Compressor membrane 20% CO2 10% CO2 Cleaned GT Steam Expander exhaust turbine CO CO Vacuum 2 2 HRSG pump Selective Air CO purge Selective Water CO2 2 Water CO membrane knockout compressor removal 2 8% CO 2 contactor Coal 18% O2

CO2 puriﬁ cation membrane

Fig. 1. Block ﬂ ow diagram of MTR’s proposed post-combustion carbon capture in: (a) an integrated gasiﬁ cation combined cycle power plant (Reprinted with permission from (2). Copyright 2014 Elsevier); and (b) a natural gas combined cycle power plant (Reprinted with permission from (3). Copyright 2013 American Chemical Society)

Due to their molecular sieving ability, zeolite separation, the Cn/Cn–1 separation factors for these membranes have also been investigated in paraffi n/ membranes are very low (Figure 2) (4). olefi n separation. Masahiko Matsukata (Waseda University, Japan) showed that in a propane-rich stream, the propylene permeance and separation factor for zeolite membranes are better than the values 50 Cn / C1 C / C reported for CMS. However membrane performance is  n n–1 strongly infl uenced by the feed composition. 40 Facilitated olefi n transport membranes incorporate a 30 reactive carrier (Ag+) in the membrane for separation.

The major technological hurdle for commercialising 20 facilitated transport membranes is the stability of the Separation factor, Separation factor, + Ag carrier. Yong Soo Kang (Hanyang University, 10 Korea) investigated membranes using Ag nanoparticles with positively induced charge, as a stable reactive 0 Ethane Propane Butane carrier. An electron acceptor ligand is coordinated to the Ag nanoparticles to induce a positive change on the Fig. 2. Highest C4/C1 membrane separation, plotted from data reported in (4) particles. These positively charged Ag nanoparticles, which are embedded into a polymeric matrix, show long term stability in oleﬁ n/parafﬁ n separation.

2.3 Hydrocarbon Separation 3. Liquid Separation Yuri Yampolskii (Russian Academy of Sciences) This section on liquid separation will discuss reviewed the membranes used for C2+ removal from advancement in membranes for pervaporation, organic natural gas. Rubbery membranes are commonly used solvent nanofi ltration and waste water treatment. in this application, where the current state-of-the-art 3.1 Pervaporation/Vapour Permeation membranes are polyacetylene type polymers. A recent Membranes development is a novel norbornene polymer membrane with a fl exible Si-O group. Although selectivity of these Pervaporation was fi rst commercialised by GFT in novel membranes is lower than polyacetylene type the 1980s based on cross-linked poly(vinyl alcohol) membranes, the permeance is much higher. Despite (PVA) composite membranes. Wilfredo Yave (Sulzer high separation factors being observed for C4/C1 Chemtech, Switzerland) presented the recent

47 © 2015 Johnson Matthey http://dx.doi.org/10.1595/205651315X685553 Johnson Matthey Technol. Rev., 2015, 59, (1) improvements made to the PREVAP™ membrane, from a process engineering viewpoint. Various which is a PVA composite membrane. The membrane confi gurations were investigated to use membranes was modifi ed to improve its separation performance, together with other unit operations. Heat integration stability and also lifetime. The major improvement made within the membrane process and with other separation was to have multiple selective layers instead of a single units was identifi ed to be the key to reduce operating layer as used in their previous generation of membranes. cost. Debottlenecking has been identifi ed as a possible Inorganic membranes have been investigated and opportunity to implement membranes in bioethanol used in pervaporation to avoid swelling which is separation. often encountered by polymeric membranes. The 3.2 Organic Solvent Nanofi ltration plenary lecture by Yiqun Fan (Nanjing University of Technology; and Jiuwu Hi-Tech, China) discussed Andrew Livingston (Imperial College, UK) presented on the use of polydimethylsiloxane (PDMS) supported the use of membrane separation in organic liquids. The on ceramic for pervaporation. The purpose of using main challenges in organic solvent nanofi ltration are a ceramic support is to constrain the swelling of the to increase the stability of the membrane (chemical, PDMS. Another pervaporation membrane supplied by thermal and operational), increase permeance and Jiuwu Hi-Tech is a hydrophilic NaA zeolite membrane. to obtain more precise separation. Stability can Masahiko Matsukata (Waseda University, Japan) be enhanced by performing cross-linking or using shared his work on zeolite membranes for pervaporation polymers which are inherently stable in organics. A in isopropyl alcohol (IPA) dehydration. Y-type zeolite recent development is to prepare thin fi lm composite and SSZ-13 tubular membranes were developed and membranes by interfacial polymerisation, followed by tested on a bench-scale rig located next to an IPA post-treatment to remove oligomers. This membrane production plant as shown in Figure 3. The product was found to have higher fl ux and better molecular stream from the plant was used as a feed for the test. weight cut off rejection. Process engineering tools are essential to evaluate Cheryl Tanardi (University of Twente, Netherlands) the benefi ts of using a membrane for separation. presented on the use of polymer grafted ceramic Masahiko Matsukata evaluated the process design and membranes for organic solvent nanofi ltration. A layer economic benefi ts for his studies on IPA dehydration of -Al2O3 was coated on the -Al2O3 support to using zeolite membranes as presented above. Three provide more functional groups for grafting PDMS on different methods of implementing membranes in an IPA to the support. dehydration process were considered. Results show Ludmila Peeva (Imperial College) demonstrated the that co-production of IPA with a membrane would yield use of organic solvent nanofi ltration in a continuous a higher energy saving compared to the other methods. catalytic Heck coupling reaction, where a homogeneous Ivy Huang (MTR, USA) looked at applying catalyst is used. Different materials were investigated pervaporation membranes to ethanol dehydration and PEEK was identifi ed as the most suitable material.

Fig. 3. JX-Nippon Oil and Energy’s IPA production plant and the bench-scale zeolite membrane located beside the plant (Image courtesy of Masahiko Matsukata, Waseda University, Japan (5))

The use of a membrane reactor resulted in a lower fl uorination of polyimide membranes improves the concentration of catalyst contamination in the product. membrane permeability and selectivity. However the performance of these surface fl uorinated membranes 3.3 Waste Water Treatment decays during storage. MTR have recently developed The plenary lecture by Neal Chung (National University a new perfl uoropolymer membrane from fl uorinated of Singapore) was on the use of membranes for clean polymers commonly used in optical fi bres. Compared to water production. Nanofi ltration for heavy metal their existing membrane, these new membranes exhibit ion removal was achieved by using a dual charge three times higher selectivity with comparable fl ux. membrane. This membrane comprises of a selective Mathias Ulbricht (Universität Duisburg-Essen, layer and support with opposite charges. A similar Germany) discussed the different methods to tailor concept was used to synthesise a membrane with both the surface properties of polymeric membranes. hydrophobic and hydrophilic properties for membrane One method is to synthesise the membrane from distillation, where the membrane fl ux was increased. A functionalised polymers or blend established dual skin membrane with a selective layer for forward membrane polymer materials with functionalised osmosis (FO) on one side and nanofi ltration on the copolymers. Another method to introduce other side of a support was used for shale gas waste functionality into membranes is via post-synthesis water treatment. The nanofi ltration prevents fouling of functionalisation. This can be achieved by using the membrane due to the substrate becoming clogged ultraviolet (UV) radiation or using a copolymer with an by stabilised emulsifi ed oil droplets. The advantages of attached macro-initiator. using a combination of FO and reverse osmosis (RO) Peter Budd (University of Manchester, UK) for desalination were also discussed. summarised the development of polymers of intrinsic Thomas Schiestel (Fraunhofer Institute for Interfacial microporosity (PIM) membranes. Many new PIMs Engineering and Biotechnology IGB, Germany) have been developed but PIM-1 is still the most widely presented on the use of composite adsorber studied material. Chemical modifi cation of the polymer membranes. Polymers coordinated on hydrogel precursor to introduce amines to PIMs was shown particles, which can adsorb neodymium, silver, copper to be effective in increasing the CO2 adsorption. UV and lead ions, were embedded in a microfi ltration and thermal treatment of PIM membranes is able to membrane. Stability of the membrane in fi ve adsorption- increase the selectivity while maintaining the fl ux. PIMs desorption cycles was demonstrated. are also widely investigated in mixed matrix membranes (MMMs). It was found that the different forms of 4. Polymeric and Hybrid Membranes CC3 introduced into PIM-1 caused minor changes in free volume but resulted in signifi cant change in gas 4.1 Transport Properties permeation. In the fi nal plenary lecture of ICOM 2014, Matthias Cher Hon Lau (Commonwealth Scientifi c and Wessling (RWTH Aachen University, Germany) Industrial Research Organisation (CSIRO), showed the importance of membrane geometry for Australia) used MMMs as a means to improve the both the transport properties and the membrane stability of super glassy polymeric membranes. By performance. By introducing nanometre thick dots and incorporating porous aromatic frameworks (PAF-1) into striped structures to the surface of an electrodialysis polytrimethylsilylpropyne (PTMSP), membrane ageing membrane, concentration polarisation can be was prevented. minimised. Another example shows the use of twisted fi nned hollow fi bres in a membrane bioreactor, which 5. Inorganic Membranes improves the secondary fl ow and minimises the build- up of particles on the surface. When twisted spacers Inorganic membranes were shown to exhibit better are used in ultrafi ltration (UF), higher yield fl ux and also separation rates, withstand higher temperatures and sharper molecular weight cut-off was obtained. pressures and also display better resistance towards chemicals and moisture compared to polymeric 4.2 Membrane Materials membranes. However, inorganic membranes are Zhenjie He (MTR) presented on MTR’s development expensive, diffi cult to process and prone to the on perfl uoropolymer composite membranes. Surface formation of non-selective defects.

The higher cost of manufacturing inorganic quadruple stimuli responsive membranes have been membranes was addressed by Yiqun Fan (Nanjing reported. University of Technology, China). Some of the 6.2 Novel Membrane Processes methods used to reduce costs include co-sintering, hot compressive sintering and the use of more One of the novel membrane processes reported at environmentally benign precursors. ICOM is the cyclic pressure-vacuum swing permeation In order to avoid the formation of non-selective defects process described by Xianshe Feng (University of in inorganic membranes, Aisheng Huang (Ningbo Waterloo, Canada). This process, as shown in Figure 4 Institute of Material Technology and Engineering, China) (6), is a non-steady state process which makes use used polydopamine (PDA) functionalised supports of transient conditions to maintain high permeance to synthesise zeolites and metal-organic framework through the membrane. This process uses a single (MOF) membranes. The adhesive property of PDA on pump to pressurise the feed and also to extract vacuum the support favours nucleation and growth of uniform for permeate removal. The process switches between zeolites and MOFs on the support. Seeding of the three modes, namely: (a) feed pressurisation, parent zeolite or MOF on the support was not required. (b) permeate evacuation and (c) retentate venting. ZIF-8, ZIF-90 and LTA type zeolite membranes were This process would be an advantage for a feed with synthesised using this method. low pressure. Miao Yu (University of South Carolina, USA) gave an overview on graphene and graphene oxide membranes. Graphene membranes show potential applications in both liquid and gas separation. A V4 V5 graphene membrane supported on polyamide was PF V1 V2 Membrane shown to prevent irreversible membrane fouling and Pump module also exhibit higher ﬂ ux than polyamide membranes PP for oil/water separation. In gas separation, graphene V3 membranes perform better in H /CO separation 2 2 Fig. 4. Pressure-vacuum swing permeation process as compared to polymeric and zeolite membranes. One of reported in (6). Red line shows the path for permeate the main challenges ahead for graphene membranes evacuation (Reprinted with permission from (6). Copyright is to control the porosity. The stability of graphene 2014 Elsevier) membranes under real gas conditions is also poorly understood.

6.3 Novel Applications 6. Novel Membrane Processes and Applications This section summarises the use of membranes in 6.1 Novel Membranes less commonly discussed applications presented at One class of membrane which is considerably different ICOM2014 such as biorefi nery, pharmaceutical and from other membranes reported at ICOM 2014 are biopharmaceutical uses. stimuli-responsive membranes, which have the ability to Mathias Wessling (RWTH Aachen University, respond to a change in the environment. Liang-Yin Chu Germany) proposed several areas where nanofi ltration (Sichuan University, China) gave a general overview can be utilised in a biorefi nery. One such use is for on this type of membrane, which contains an artifi cial the recovery of oxalic acid. Oxalic acid is used to smart gate where the presence of an external infl uence disintegrate lignocellulose to its individual fractions can open or close the pores of the material. The (lignin, hemi-cellulose and cellulose). Separation smart gate can be introduced before, during or after occurs via molecular weight-cut off and charge membrane synthesis. These membranes can be made exclusion. Another use of nanofi ltration in a biorefi nery to respond to temperature, pH, light, electric fi eld, is to aid downstream recovery of itaconic acid, which magnetic fi eld, ions, chemical species and biological is an important intermediate. Nanofi ltration is used to species. Membranes can also be designed to respond concentrate the feed from the fermenter and itaconic to more than one type of stimuli; dual, triple and acid can be recovered by crystallisation.

Andrew Livingston (Imperial College) demonstrated In general, there was a good mix of talks focusing the use of organic solvent nanofi ltration in liquid phase on both new membrane material development and peptide synthesis for pharmaceutical applications. applications of membranes in processes. However, This permits the use of lower amino acid excess in more attendees were observed in the material talks each sequential coupling step, while allowing ease of especially those on novel membrane materials such as separation. The membrane is used to remove unreacted graphene. Despite the massive scale and number of amino acid and solvent between each step. This attendees, ICOM 2014 was very well organised with synthesis method can also be used to synthesise mono- plenty of opportunities to network. The next ICOM will dispersed heterobifunctional polyethylene glycol (PEG). be held in San Francisco, USA, in 2017. Dieter Melzner (Sartorius-Stedim Biotech GmbH, Germany) presented on the use of membranes for Refer ences virus separation. Separation is via size exclusion and/ or adsorptive mechanisms. Membrane chromatography 1 The 10th International Congress on Membranes and is also used in virus processing, which can operate in Membrane Processes, Suzhou, China, 20th–25th July, 2014 two modes: (i) bind and elute mode, used to purify virus particles; and (ii) polishing mode, used to adsorb impurities 2 P. Hao, J. G. Wijmans, J. Kniep and R. W. Baker, J. while allowing the virus product to fl ow through. Membrane Sci., 2014, 462 , 131 3 T. C. Merkel, X. Wei, Z. He, L. S. White, J. G. Wijmans 7. Conclusion and R. W. Baker, Ind. Eng. Chem. Res., 2013, 52, (3), 1150 The study and understanding of membranes and 4 Yu. Yampolskii, L. Starannikova, N. Belov, M. membrane processes continues to be an essential Bermeshev, M. Gringolts and E. Finkelshtein, J. part of research to develop better fundamental Membrane Sci., 2014, 453 , 532 understanding and allow possible industrial exploitation. 5 M. Matsukata, ‘Prospects of Zeolite Membrane This review covers emerging areas in gas separation Technologies for Energy and Chemical Processes’, and liquid separation and also recent innovations in in Proceedings of the 10th International Congress membrane materials. Novel membrane processes on Membranes and Membrane Processes, Suzhou, and applications were also briefl y discussed. However China, 20th–25th July, 2014 this review only represents a small portion of the work 6 Y. Chen, D. Lawless and X. Feng, Sep. Purif. Technol., presented at ICOM 2014. 2014, 125, 301

The Reviewer

Xavier (Xian-Yang) Quek graduated with a BEng in Chemical Engineering from Nanyang Technological University, Singapore, and a PhD in heterogeneous catalysis from Eindhoven University of Technology, the Netherlands. In 2013, he joined the Low Carbon Technology group at Johnson Matthey Technology Centre, Sonning Common, UK. His current research focuses on the use of Pd and Pd-alloy membranes for pre-combustion carbon capture. He also has a wider interest in membranes and the use of membranes in various processes.

In the Lab Development of Carbon Based Electrochemical Sensors for Water Analysis

Johnson Matthey Technology Review features new laboratory research

Julie Macpherson is a Professor in the Department of Chemistry at the University of Warwick, UK. About the Researcher Her research focuses on the development of sensors based on different forms of carbon, including conducting diamond, carbon nanotubes and graphene, with a range of applications in environmental monitoring, healthcare technologies and water research. She has published over 150 papers and 14 patents.

About the Research

Carbon is an extremely interesting element which can be arranged in different forms, two of which are • Name: Julie Macpherson of interest in the group’s research: diamond (sp3) • Position: Professor/Royal Society Industry Fellow 2 and carbon nanotubes (sp ). The group is working • Department: Chemistry towards an electrochemical understanding of the • University: University of Warwick different forms of carbon and how the material can be • Street: Gibbet Hill Road appropriately structured in order to produce the most • City: Coventry effi cient sensor for a wide range of applications. As the • Post Code: CV4 7AL sensor is often based on electrochemical principles, • Country: UK the material must conduct. For sp2 carbon this is not • Email Address: [email protected] a problem; for diamond it is. Hence during synthesis diamond is doped with boron (boron doped diamond (BDD)). At suffi cient doping levels the material turns black and electrically behaves as a semi-metal. In the for long periods of time, continuously monitoring. conducting diamond arena, work with the industrial BDD is also extremely robust when subject to high diamond company Element Six has focused on applied potentials, for example, for the production of methods to produce BDD electrodes in any geometry, ozone or other oxidative species in water treatment where the electrode component is insulated in processes. Figure 1 shows two examples of all- diamond; this has led to a variety of solution-based diamond sensors, from the group. sensing applications. All-diamond electrodes enable The use of a dual electrode confi guration has the sensor to be placed in extreme or complex been used, for example, as a means of controlling environments, where other electrode materials fail, the local pH environment of the sensing electrode.

(a) Insulating diamond (b) Insulating diamond BDD

BDD

Fig. 1. (a) Ring-disc all-diamond sensor structure. The disc has a diameter of 3 mm; (b) all-diamond multiple band electrode sensor. The width of the diamond chip is ~1 cm × 1 cm. For both images the black tracks are BDD and the transparent areas are insulating diamond (Image copyright Jon C. Newland, University of Warwick, UK)

The outer or upstream BDD electrode (in a fl uidic walled carbon nanotubes (SWNTs), with a focus fl ow cell) can be used to electrochemically break on healthcare applications. Growth of SWNTs down water, creating a controlled pH environment takes place in the laboratory. For trace level over the detector electrode to optimise the analysis, the optimal arrangement in terms of sensing process of interest. These structures sensitivity, time and cost was a two dimensional have been successfully deployed to detect heavy network of SWNTs grown directly onto insulating metal (for example, mercury) ions and dissolved hydrogen sulfi de in water (Figure 2) in far from substrates. When incorporated into a suitable ideal pH conditions. The BDD electrodes can also microfluidic flow system, these electrodes were be combined with other measurement techniques shown to be capable of sub-nanomolar detection to further enhance analytical capabilities. For of dopamine and ferrocene labelled molecules example, electrochemical X-ray fl uorescence (Figure 3) in biologically relevant solutions. is a recently emerged technique based on BDD Working with high resolution electrochemical electrodes which enables unique chemical imaging techniques it was also possible to identifi cation and quantifi cation of complex ‘soups’ elucidate the electrochemical behaviour and of metal ions in solution, with the ultimate aim being to measure these directly at the source. sensing capabilities of SWNTs at the single tube The group is also investigating the level, showing that the entire sidewall is active electrochemical sensing capabilities of single (Figure 4).

(a) BDD ring (b) H2O pK = 6.88 pK = 14.15 22++ 0 a a HHgg HHgg – 2– H2S H2S HS  S + H2O H OH– H O HS– S0 Flow H S 2 + 2 OH– H – H2O OH + + H H Insulating + H + diamond H + H+ H – – Intrinsic diamond BDD disc OH generator HS detector

Fig. 2. pH optimisation of a dual detector electrode using two different confi gurations: (a) generation of H+ by the ring to control the pH environment of the disc (Adapted with permission from T. L. Read, E. Bitziou, M. B. Joseph and J. V. Macpherson, Anal. Chem., 2014, 86, (1), 367. Copyright (2014) American Chemical Society); (b) upstream generation of OH– in a fl ow device fl oods the downstream detector electrode, optimising the pH of the sensor (Reprinted with permission from E. Bitziou, M. B. Joseph, T. L. Read, N. Palmer, T. Mollart, M. E. Newton and J. V. Macpherson, Anal. Chem., 2014, 86, (21), 10834. Copyright (2014) American Chemical Society)

(a) (b)

I, nA cm I, nA –5 –10 –15 –20 –25 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 E/V vs. Ag/AgCl

Fig. 3. (a) Optical picture of a SWNT network chip for sensing applications (Image copyright Petr Dudin, University of Warwick, UK); (b) electron microscope image of a SWNT network electrode (10 μm × 10 μm); (c) cyclic voltammogram for FcTMA+ detection – red line shows a detection cyclic voltammogram for 25 nM (Reprinted with permission from P. Bertoncello, J. P. Edgeworth, J. V. Macpherson and P. R. Unwin, J. Am. Chem. Soc., 2007, 129, (36), 10982. Copyright (2007) American Chemical Society)

(a) 12

(b) 0.25 V I V2 EC

8 , pA V1 0.3 V I2 4 Red Ox 0.35 V 0

0.6 V

SECCM 5 IEC μ

0.5 V m

VAppl = 0.4 V

Fig. 4. (a) Set-up for scanning electrochemical cell imaging of a single SWNT; (b) electrochemical image of a single SWNT. As the potential on the SWNT is successively increased the SWNT current increases. The sidewall is shown to be active (Reprinted with permission from A. G. Güell, K. E. Meadows, P. V. Dudin, N. Ebejer, J. V. Macpherson and P. R. Unwin, Nano Lett., 2014, 14, (1), 220. Copyright (2014) American Chemical Society)

Selected Publications

J. V. Macpherson, Phys. Chem. Chem. Phys., 2015, doi: 10.1039/C4CP04022H E. Bitziou, M. B. Joseph, T. L. Read, N. Palmer, T. Mollart, M. E. Newton and J. V. Macpherson, Anal. Chem., 2014, 86, (21), 10834 T. L. Read, E. Bitziou, M. B. Joseph and J. V. Macpherson, Anal. Chem., 2014, 86, (1), 367 L. A. Hutton, G. D. O’Neil, T. L. Read, Z. J. Ayres, M. E. Newton and J. V. Macpherson, Anal. Chem., 2014, 86, (9), 4566 M. B. Joseph, E. Bitziou, T. L. Read, L. Meng, N. L. Palmer, T. P. Mollart. M. E. Newton and J. V. Macpherson, Anal. Chem., 2014, 86, (11), 5238 A. G. Güell, K. E. Meadows, P. V. Dudin, N. Ebejer, J. V. Macpherson and P. R. Unwin, Nano Lett., 2014, 14, (1), 220 S. Sansuk, E. Bitziou, M..B. Joseph, J. A. Covington, M. G. Boutelle, P. R. Unwin and J. V. Macpherson, Anal. Chem., 2013, 85, (1), 163 L. A. Hutton, J. G. Iacobini, E. Bitziou, R. B. Channon, M. E. Newton and J. V. Macpherson, Anal. Chem., 2013, 85, (15), 7230 H. V. Patten, K. E. Meadows, L. A. Hutton, J. G. Iacobini, D. Battistel, K. McKelvey, A. W. Colburn, M. E. Newton, J. V. Macpherson and P. R. Unwin, Angew. Chem. Int. Ed., 2012, 51, (28), 7002 P. V. Dudin, M. E. Snowden, J. V. Macpherson and P. R. Unwin, ACS Nano, 2011, 5, (12), 10017 I. Dumitrescu, J. P. Edgeworth, P. R. Unwin and J. V. Macpherson, Adv. Mater., 2009, 21, (30), 3105 I. Dumitrescu, P. R. Unwin and J. V. Macpherson, Chem. Comm., 2009, (45), 6886 P. Bertoncello, J. P. Edgeworth, J. V. Macpherson and P. R. Unwin, J. Am. Chem. Soc., 2007, 129, (36), 10982

17th International Meeting on Lithium Batteries

Highlights of the latest research on post-lithium-ion battery chemistry

Reviewed by Mario Joost* and Sam Alexander increased likewise. The International Meeting on Johnson Matthey Technology Centre, Sonning Lithium Batteries (IMLB) has been held biannually Common, Reading, RG4 9NH, UK since 1982 and is one of the top meetings in the Li battery community. It is organised by an international *Email: [email protected] executive committee, currently comprising of 24 international scientists. Following Jeju, Korea, in 2012, this year’s meeting was held in Como, Italy. 1. Introduction It was co-organised by the Electrochemical Society (ECS) which will also publish dedicated special issues Within the last 20 years, publication numbers in in Journal of the Electrochemical Society and ECS the ﬁ eld of lithium battery research have increased Transactions. Around 1000 people attended the from a few hundred in the mid 1990s to more than meeting with 40+ keynote speakers, presenting in nine 4500 publications in 2013 (Figure 1). It has grown plenary sessions and three large poster sessions with to a major research topic, with many universities, more than 500 contributions. Further details on the state laboratories and commercial research 17th IMLB meeting including details of the scientiﬁ c and development (R&D) facilities involved. The programme and biographies of the invited speakers number of meetings dedicated to battery work has can be found on the conference website (1).

1000 1000 Related to: Li-ion Li-air Li-sulfur Sodium 100 100 c publications ﬁ

10 10 Number of scienti 1 1 1980 1985 1990 1995 2000 2005 2010 Year Fig. 1. Numbers of scientiﬁ c publications related to different types of battery. The search was run on keywords in the manuscript titles and abstracts. Note that the numbers for sodium batteries include the (high-temperature) molten salt and Na-sulfur systems

In recent years there has been increasing interest in next-generation, ‘beyond lithium-ion’ battery technologies, especially in Li-air, Li-sulfur and sodium based chemistries. A major theme of the meeting addressed recent advances in beyond Li-ion batteries, where novelty was a key requirement for paper acceptance. The main areas of interest were Li battery related science and technology such as, but not limited to: electrode materials, electrolytes, Li-air, Li-sulfur, sodium batteries, new analytical tools, computational work and safety. Due to the huge amount of contributions during this 100 nm conference, only a few highlights of each main topic are included in this review. For a detailed overview of the Fig. 2. Li2O2 toroidal discs on a porous carbon electrode conference contents, the interested reader is referred to the conference homepage (1). Large, toroidal shaped discs in high donor number 2. Lithium-Oxygen Batteries solvents were also found by Peter Bruce’s group (University of Oxford, UK). According to his theory, No other battery system is the subject of such high solubility of the superoxide radical in the controversial discussion as Li-oxygen. The list of electrolyte leads to Li2O2 growth from the solution ‘unsolvable’ problems is long and small successes rather than from the electrode surface. The addition of are contrasted by big setbacks. The many reports redox mediators was discussed to aid the dissolution on stability issues of electrolyte solvents are just one of Li2O2 on charge and therefore increase the rate example (2–4). Reaction mechanisms of the oxygen capability (8). Also focused on the donor abilities of reduction reaction (ORR) and the oxygen evolution electrolyte solvents, K. M. Abraham’s (Northeastern reaction (OER) are still not explained satisfactorily (5) University, USA) approach was based on the ‘hard and side reactions are omnipresent. Contamination and soft acids and bases’ (HSAB) concept. Ionic originating from the cathode, which is open to the liquids (ILs) with soft cations (such as 1-methyl-1- environment, cannot be blocked sufﬁ ciently (6). butyl-pyrrolidinium bis(triﬂ ouromethanesulfonyl)imide

From the start, the question of the preferred (Pyr14TFSI) and 1-ethyl-3-methylimidazolium bis- morphology of Li2O2 deposition was heavily discussed (trifl uoromethanesulfonyl)imide (EMITFSI)) reduce the amongst the speakers. Together with her co- Li+ acidity in organic electrolytes and therefore increase – workers, Yang Shao-Horn (Massachusetts Institute of the lifetime of initially formed O2 (9). The potential of Technology (MIT), USA) studied the effect of solvation Pyr14TFSI was demonstrated by Jakub Reiter (BMW on Li-O2 redox reactions. The results revealed the Group, Germany) when he presented results of an formation of very small Li2O2 particles at high discharge ionic liquid electrolyte (Pyr14TFSI/LiTFSI (9:1)), applied rates and/or when using a solvent with low solvation in a Li-air battery using a Super-P® cathode and a Li- power (here: dimethylether (DME)). At low rates and/or metal anode (10). when using solvents with higher donor numbers (here: Tailoring Li2O2 morphology by providing an optimised dimethyl sulfoxide (DMSO)), larger, disc-like particles cathode structure was the idea of Xin-Bo Zhang and co- (Figure 2) are formed (7). Lower overpotential (i.e. workers (Chinese Academy of Sciences, China). A free- higher discharge voltage) was observed in the latter standing honeycomb-like palladium modifi ed hollow case. Increased solvation power due to high donor spherical carbon was applied as Li-air cathode, which + numbers lowers the energy levels of the Li/Li redox led to organised, toroidal nanosheets of Li2O2. More 2– –1 reaction and increases that of the O2/2*O reaction. than 100 cycles at a current density of 300 mA g and a Larger particles seemed to improve the kinetics and specifi c capacity limit of 1000 mAh g–1 were presented better fi ll the volume of carbon pores, whereas smaller (11). In contrast to the results discussed before, Li2O2 particles have a reduced overpotential (5). was observed to form rapidly if the superoxide binds

57 © 2015 Johnson Matthey http://dx.doi.org/10.1595/205651315X685733 Johnson Matthey Technol. Rev., 2015, 59, (1) well on the cathode surface. Atomically dispersed A second approach to stop polysulfi de migration Fe/N/C composite as bifunctional catalysts showed would be an electrolyte which would act as a better performance, exhibiting fewer side reactions polysulfi de barrier. A polymer electrolyte made from than a classic α-manganese(IV) oxide (MnO2) catalyst poly ethylene(oxide) with 10 wt% ZrO2, LiCF3SO3 (12). and Li2S was presented by Jusef Hassoun (Sapienza The possible instability of the carbon cathode and University of Rome, Italy). Cells had to be operated – –1 the related importance of the 2e per O2 ratio for the at 70ºC to deliver 900 mAh g (30). Doping the ORR and OER was a key message from Peter Bruce electrolyte (tetraglyme) with a polysulfi de (Li2S8) (13–15). Arumugam Manthiram (University of Texas, proved to decrease the internal resistance and USA) suggested hybrid Li-air batteries as a solution seemed to buffer further polysulfi de dissolution (31). to the aforementioned problems. The benefi ts of an The incorporation of ionic liquids might also be a viable aqueous cathodic compartment and a non-aqueous solution to the problem. Aleksandar Matic (Chalmers anodic compartment can compensate for the increased University, Sweden) presented imidazolium- and complexity of the system (16, 17). Novel catalysts like pyrrolidinium-based electrolytes (32), some of them iridium(IV) oxide (IrO2) (18), low-temperature Li1–xCoO2 mixed with 1,3-dioxolane or glymes (33). Linda F. or LiMn1.5Ni0.5O4 were successfully employed (19). Nazar could achieve decreased polysulfi de dissolution Other workers used a cobalt phthalocyanine-derived in electrolyte systems based on 1,3-dioxolane, catalyst to enable the full reduction of O2 to Li2O, thus 1,2-dimethoxyethane and bis(trifl uoromethylsulfonyl)- utilising the full theoretical range of a Li-air cell (20). To imide (TFSI) salts (34). She also presented an in reduce safety issues, replacing the Li metal anode with operando X-ray absorption spectroscopy technique

SnC, Fe0.1Zn0.9O or SiC was suggested (10). to identify the different sulfur species (35). As an alternative approach, a membrane-free polysulﬁ de 3. Lithium-Sulfur Batteries ﬂ ow battery was presented by Yi Cui (36).

Lithium-sulfur (Li-S) batteries are expected to be closer 4. Sodium Batteries to a marketable product than Li-air batteries. A major remaining challenge, addressed in many contributions, High-temperature Na batteries were developed is the high solubility of polysulfi de intermediates formed as molten Na-S or Na-NiCl2 (ZEBRA) batteries in during the stepwise (but in no case straightforward) the 1980s. However, these systems were quickly reduction from S8 to the fi nal discharge product Li2S pushed aside by the success of Li-ion batteries. Low- (21, 22). These polysulfi des migrate to the anode, temperature sodium systems, like Li-ion technology, ending up as a self-discharge promoting redox shuttle have now started to gain interest within the last few or as a deposit blocking the anode surface (23, 24). years (Figure 1). They can certainly benefi t from Yi Cui (Stanford University, USA) started with a quick experience in the Li-ion fi eld but knowledge transfer will overview of the recent evolution of Li-S cathodes (from not be as straightforward as it may seem. sulfur/carbon mixtures to encapsulated hollow particles) ‘Walking on the sodium side’ was the slogan of and he summarised by stating that no satisfying solution Maria Rosa Palacín (Institut de Ciència de Materials to ‘capture’ the sulfur has been found yet. Tin-doped de Barcelona-Consejo Superior de Investigaciones indium oxide was found to fi x polysulfi de to carbon (25). Científi cas (ICMAB-CSIC), Spain) as she opened the Core-shell material showed increased sulfur ‘trapping’ Na-ion related talks. Major safety concerns come with but still lost polysulfi des during cycling (26, 27). Yu- the use of Na metal as anode, which reacts more fi ercely Guo Guo (Chinese Academy of Sciences) tried to start with water than Li. Carbon would be one alterative (37), from smaller sulfur homologues (S2–4) which could be but Ti-based insertion materials, especially Na2Ti3O7, successfully trapped inside microporous carbon or could also give reasonable performance, with Na carbon nanotubes (CNTs) (28). The group of Linda F. insertion potentials as low as 0.3 V vs. Na+/Na (38, Nazar (University of Waterloo, Canada) replaced the 39). Young-Jun Kim (Korea Electronics Technology carbon support with titania (TiO2), alumina (Al2O3) and Institute) would employ sodium metal in systems like titanium oxide (Ti4O7) and successfully reduced the Na-S, Na-NiCl2, Na-O2 and Na-ion when electrolytes fade rate (29). like NaAlCl4*SO2 or organic liquids would prove

58 © 2015 Johnson Matthey http://dx.doi.org/10.1595/205651315X685733 Johnson Matthey Technol. Rev., 2015, 59, (1) suitable. However, side reactions with the electrolyte an intercalation cathode. Modern versions are doped are an issue for sodium. Maria Rosa Palacín’s group with Ni and Mn (known as NMC) with the formula found ethylene carbonate and/or propylene carbonate Li[NixMnyCoz]O2, where x + y + z = 1. The transition based solutions with sodium perchlorate (NaClO4) to metal ratios can be altered to control properties such be relatively stable (40). Laurence Croguennec (Institut as capacity and operating potential. de Chimie de la Matière Condensée de Bordeaux- One major issue with NMC type compounds is Centre National de la Recherche Scientiﬁ que (ICMCB- structural instability caused by either collapse of the

CNRS), France) suggested ﬂ uorophosphates as high MO6 layers on Li removal or by migration of transition energy density positive electrodes for Na (and Li) metals into the empty Li positions. Increasing the Ni batteries. In particular the compound Na3V2(PO4)2F3 content in Li[NixMnyCoz]O2 leads to increased capacity was investigated, since vanadium offers a wide range but also decreased capacity retention and concomitant of stable oxidation states and structures in Na (41, 42) decrease in structural stability. When x is as high as and Li (43) containing compounds. 0.85, the material has a higher initial capacity, but 90% of the structure collapses during cycling, leading to fast 5. Layered Lithium-Ion Battery Cathode capacity loss. Therefore Yang-Kook Sun (Hangyang Materials University, Korea) described a core-shell material with increased capacity in the core and good stability (and There is a large drive to increase the operating potential therefore high safety) on the surface (44). However, of Li-ion batteries in order to increase the gravimetric these materials do not perform well due to separation of energy density. The gravimetric energy density is the the shell from the core during cycling, caused by different product of capacity and the mean operating voltage volume change ratios. Applying a gradient throughout and therefore can be altered by changing either of the whole particle, using a slow concentration change these material properties. Layered metal oxides have in the core and a fast concentration change in the shell, been used as Li-ion battery cathodes since the ﬁ rst led to mechanically stable particles while keeping the commercial battery produced by Sony in the early capacity and stability advantages (45, 46).

1990s. These materials are made up of slabs of Al2O3 coatings as an alternative method for stabilising edge sharing MO6 octahedra (where M is Ni, Co and/ NMC particles were described by Kuniaki Tatsumi or Mn) separated by layers of Li cations (Figure 3). (National Institute of Advanced Industrial Science and

The elemental composition of these materials has Technology (AIST), Japan). Li[Ni1/3Mn1/3Co1/3]O2 was changed signiﬁ cantly since Sony ﬁ rst used LiCoO2 as mechanochemically coated, the Al2O3 was uniformly distributed on the surface with no migration into the bulk particle. The material showed greatly improved cycling performance, even at elevated temperatures. The

Al2O3 coating suppressed crack formation, reduced degradation of charge transfer sites and increased cycling stability at 1 C. Without coating, carbonates and LiF formed on the particle surfaces, concomitant with an increase in the detrimental cubic NMC phase at particle surfaces (47). A third strategy to increase the stability of NMC based layered compounds is to make a composite

of Li2MnO3 and LiNixMnyCozO2, also known as Li-rich NMC. Li2MnO3 is structurally related to LiNixMnyCozO2; however excess Li resides in the transition metal layers. This results in the presence of electrochemically inactive Mn4+ which acts as a structural scaffold and prevents collapse of the metal oxide layers. The resulting compound has a reversible Fig. 3. Structure of LiMO : green = lithium, purple = metal (M) 2 –1 and red = oxygen (O) capacity as high as 200 mAh g . However, transition metal cations migrate from the transition metal layers

59 © 2015 Johnson Matthey http://dx.doi.org/10.1595/205651315X685733 Johnson Matthey Technol. Rev., 2015, 59, (1) to the Li layers, leading to voltage fade over time. formed in which many particles were combined to The cause of this migration is not fully understood, form macroscopically sized particles. These ‘carbon however, Jean-Marie Tarascon shed some light coated matrix’ particles showed improved performance on the problem using simpliﬁ ed compounds like compared to micron sized particles (50, 51). In a

Li2Ru(IV)1–ySn(IV)yO3 (as opposed to Li2MnO3). This separate piece of work TiO2 nanorods were carbon 3d-metal-free compound could be cycled over 100 coated using polyacrylonitrile (PAN) as precursor. The times, delivering reasonably high capacity. X-ray block copolymer was anchored to the TiO2 surface diffraction (XRD) was used to show the onset of before carbonising to create an even carbon layer. large disorder on charging which was recovered on The performance of these new nanorods was greatly discharge. High-angle annular dark-fi eld-scanning improved with respect to the uncoated sample (52). transmission electron microscopy (HAADF-STEM) Karim Zaghib (Hydro-Québec, Canada) described showed massive cationic migration to the Li layers the latest advances in trying to stabilise reactive Li on charging which returned to the completely ordered metal anodes with polymer coatings. The challenges state when subsequently discharged. Despite this and opportunities in developing thin Li metal with a cationic migration the Li2Ru(IV)1–ySn(IV)yO3 structure stable solid electrolyte interphase (SEI) as the negative shows no voltage fade over time. Testing the impact electrode were discussed in this presentation. In a of ion size (Sn4+>Ti 4+>Mn4+), the titanium compound unique process, Li metal was extruded to 20 μm thin –1 Li2Ru0.75Ti0.25O3 was synthesised. It showed the worst fi lms at a speed of 30 m min . The surface was treated voltage fade. A combination of X-ray photoelectron with a special solution and pressed against a solid spectroscopy (XPS) and electron microscopy showed polymer electrolyte fi lm (dry polymer and ionic liquid- that upon cycling, Ti4+ accumulates in tetrahedral polymer electrolytes). Due to the surface treatment, sites between the metal oxide and Li layers where it the very clean conditions and constant pressure on the is no longer active. Preventing metals entering these stack, long term cycling (3000 cycles at C/3 and 80ºC) tetrahedral sites will prevent voltage fade in layered- without major fading and dendrite growth was possible. layered compounds. Sn4+ is therefore attractive to Nanostructuring has become a key requirement for reduce voltage fade, however replacing Mn with Sn the utilisation of high capacity silicon anodes. Whilst has not worked. Compounds with the stoichiometry these anodes have very high capacities they can be n+ m+ Li4(M ,M )O6 where m + n = 8 are considered best diffi cult to utilise, due to a large volume change of as an answer to the voltage fade issue in Li-rich around 300% occurring on lithiation. Fei Luo (Chinese NMCs (48, 49). Academy of Sciences) described how the volume variation in Si/C composites is very anisotropic. Si/C 6. Anode Materials particles were synthesised as nanorods attached to the substrate which allowed for the large volume Future anode materials are more likely to be conversion expansion. There was a complex evolution of particle or alloying type materials rather than insertion materials shape caused by amorphous to amorphous diffusion- like the state-of-the-art graphite anode. Complex controlled phase transitions; however porous fi lms did reaction mechanisms and high volume changes present not prevent cracking. Isolated Si column structures challenges for these materials. Nanostructuring and showed much less cracking than dense fi lms (53). coating with polymers or carbons are two approaches to protect materials against side reactions and ensure 7. Electrolytes good cycling, even at high rates. + Fe3O4 is a conversion material which reacts with Li Increasing the operational potential of the cathodes to form Li2O and Fe metal. The Fe metal produced can brings new challenges for the electrolyte. Jeff Dahn also alloy with Li as the battery continues to discharge. and Laura Downie (Dalhousie University, Canada)

Fe3O4 has in the past been doped with Zn to produce described their approach to tackle increased side ZnFe2O4, however this material has poor coulombic reactions originating from electrolyte oxidation on efﬁ ciency. Stefano Passerini (Helmholtz Institute, Ulm, high voltage material surfaces. Commonly used

Germany) presented his group’s work in which ZnFe2O4 carbonate based electrolyte solutions show increasing was coated with carbon using glucose as precursor. In reaction rates above 4.2 V vs. Li+/Li. Additives such as addition to the particle coating, a carbon matrix was vinylidene carbonate (VC), tris(trimethylsilyl)phosphite

(TTSPi) and methylene methanedisulfonate (MMDS) temperature (Tg) (and therefore decreased conductivity) (54) can be used to increase this maximum operating with increasing salt concentration. In poly(ethylene potential (55). NMC pouch cells were cycled at C/10 carbonate) (PEC) it is the other way around and this with low temperature impedance measurements made might be an interesting solution for the problem of every 10 cycles. The results of this study showed that low conductivity at sub-ambient temperatures (66). there was a very large increase in charge transfer Polyelectrolytes have the anion attached to the resistance when cells are cycled above 4.4 V. Increased backbone and the Li transport number should therefore electrolyte oxidation is correlated to increased parasitic be 1, since Li+ is the only mobile species. However, heat fl ow, detected via isothermal microcalorimetry. the overall conductivity remains low for these systems When more than 100 μV of heat is generated during so far. Armand’s group linked TFSI anions and PEO cycling, the entire electrolyte of an A5 pouch cell elements to a polystyrene backbone which could would be consumed within one year (56–58). Jeff achieve conductivities around 10–5 S cm–1 at 60ºC Dahn carefully summarised that the electrolyte stability (67, 68). The question of whether PEO based systems usually increases with the number of additives. can successfully suppress Li dendrite formation was Ceramic solid state electrolytes as a safe high- investigated by the group of Noboyuki Imanishi (Mie voltage solution were presented by Chihiro Yada University, Japan). A PEO18LiTFSI with 10 wt% BaTiO3 (Toyota Motor Europe). A main problem is the huge system was swollen with ionic liquid which reduced the charge-transfer resistance at the interfaces due to bulk resistance of the battery and increased the cycle fast Li-ion depletion upon load. Dielectric modifi cation performance. In situ scanning electron microscopy of these layers using BaTiO3 could decrease this investigations showed that dendrite growth could be resistance and increase the quantity of Li at the retarded. interface. Li1.1(Nb0.5Ta 0.5)0.9O3–δ was identifi ed as a promising material with high permeation and Li-ion 8. Conclusions mobility (59). Flexible solid state electrolytes which can be printed in any shape were presented as a key This conference was loaded with excellent talks and an component for future electronic devices (wearable enormous number of interesting poster contributions. technology, fl exible devices) by Sang-Young Lee It was a very well organised event and the beautiful (Ulsan National Institute of Science and Technology weather underlined the lovely venue. It was obvious that (UNIST), Korea). The plastic crystal electrolyte (PCE) the research on post Li-ion systems is a quickly growing consists of alumina/silica ceramic nanoparticles, fi eld, which already generate dedicated conferences. ethylene carbonate, succinonitrile and an ultraviolet One can happily look forward to the next IMLB meeting (UV) cross linker. The electrolyte ink has no in 2016 which will be held in Chicago, USA. additional processing solvents and shows thixotropic behaviour. Addition of ethoxylated trimethylolpropane References triacrylate (ETPTA) successfully suppresses dendrite growth. Cells can be stretched and bent during 1. The 17th International Meeting on Lithium Batteries, operation (60, 61). Maria Forsyth (Deakin University, 10th–14th June, 2014, Como, Italy Australia) presented organic ionic plastic crystals 2. D. G. Kwabi, N. Ortiz-Vitoriano, S. A. Freunberger, (OIPCs, solidifi ed ionic liquids), which show good Y. Chen, N. Imanishi, P. G. Bruce and Y. Shao-Horn, electrochemical behaviour. Phosphonium based MRS Bull., 2014, 39, (5), 443 OIPCs incorporating Na salts show electrochemical 3. M. Balaish, A. Kraytsberg and Y. Ein-Eli, Phys. Chem. properties similar to Li containing analogues Chem. Phys., 2014, 16, (7), 2801 (62–64). However, the presence of multiple phases, 4. M. D. Bhatt, H. Geaney, M. Nolan and C. O’Dwyer, high viscosity and high-temperature eutectics remain Phys. Chem. Chem. Phys., 2014, 16, (24), 12093 issues which can be altered by a careful choice of ion 5. B. M. Gallant, D. G. Kwabi, R. R. Mitchell, J. Zhou, C. combination (65). V. Thompson and Y. Shao-Horn, Energy Environ. Sci., The fact that polymer electrolytes are still solid, after 30 2013, 6, (8), 2518 years of research, was no cause for concern for Michel 6. M. H. Cho, J. Trottier, C. Gagnon, P. Hovington, D. Armand (CIC EnergiGUNE, Spain). Poly(ethylene Clément, A. Vijh, C.-S. Kim, A. Guerfi , R. Black, L. Nazar oxide) (PEO) suffers from increasing glass transition and K. Zaghib, J. Power Sources, 2014, 268, 565

7. B. Horstmann, B. Gallant, R. Mitchell, W. G. Bessler, 27. G. Zheng, Y. Yang, J. J. Cha, S. S. Hong and Y. Cui, Y. Shao-Horn and M. Z. Bazant, J. Phys. Chem. Lett., Nano Lett., 2011, 11, (10), 4462 2013, 4, (24), 4217 28. S. Xin, L. Gu, N.-H. Zhao, Y.-X. Yin, L.-J. Zhou, Y.-G. 8. Y. Chen, S. A. Freunberger, Z. Peng, O. Fontaine and Guo and L.-J. Wan, J. Am. Chem. Soc., 2012, 134, P. G. Bruce, Nature Chem., 2013, 5, (6), 489 (45), 18510 9. C. J. Allen, J. Hwang, R. Kautz, S. Mukerjee, E. J. 29. Q. Pang, D. Kundu, M. Cuisinier and L. F. Nazar, Plichta, M. A. Hendrickson and K. M. Abraham, J. Nature Commun., 2014, 5, 4759 Phys. Chem. C, 2012, 116, (39), 20755 30. J. Hassoun and B. Scrosati, Adv. Mater., 2010, 22, 10. G. A. Elia, J. Hassoun, W.-J. Kwak, Y.-K. Sun, B. (45), 5198 Scrosati, F. Mueller, D. Bresser, S. Passerini, P. 31. D.-J. Lee, M. Agostini, J.-W. Park, Y.-K. Sun, J. Oberhumer, N. Tsiouvaras and J. Reiter, Nano Lett., Hassoun and B. Scrosati, ChemSusChem, 2013, 6, 2014, 14, (11), 6572 (12), 2245 11. J.-J. Xu, Z.-L. Wang, D. Xu, L.-L. Zhang and X.-B. 32. S. Xiong, K. Xiea, E. Blomberg, P. Jacobsson and A. Zhang, Nature Commun., 2013, 4, 2438 Matic, J. Power Sources, 2014, 252, 150 12. J.-L. Shui, N. K. Karan, M. Balasubramanian, 33. K. Ueno, K. Yoshida, M. Tsuchiya, N. Tachikawa, K. S.-Y. Li and D.-J. Liu, J. Am. Chem. Soc., 2012, 134, Dokko and M. Watanabe, J. Phys. Chem. B, 2012, (40), 16654 116, (36), 11323 13. M. M. Ottakam Thotiyl, S. A. Freunberger, Z. Peng and 34. J. Schuster, G. He, B. Mandlmeier, T. Yim, K. T. Lee, P. G. Bruce, J. Am. Chem. Soc., 2013, 135, (1), 494 T. Bein and L. F. Nazar, Angew. Chem. Int. Ed., 2012, 14. M. M. Ottakam Thotiyl, S. A. Freunberger, Z. Peng, Y. 51, (15), 3591 Chen, Z. Liu and P. G. Bruce, Nature Mater., 2013, 12, 35. M. Cuisinier, P.-E. Cabelguen, S. Evers, G. He, M. (11), 1050 Kolbeck, A. Garsuch, T. Bolin, M. Balasubramanian and 15. Z. Peng, S. A. Freunberger, Y. Chen and P. G. Bruce, L. F. Nazar, J. Phys. Chem. Lett., 2013, 4, (19), 3227 Science, 2012, 337, (6094), 563 36. Y. Yang, G. Zheng and Y. Cui, Energy Environ. Sci., 16. L. Li, X. Zhao, Y. Fu and A. Manthiram, Phys. Chem. 2013, 6, (5), 1552 Chem. Phys., 2012, 14, (37), 12737 37. A. Ponrouch, A. R. Goñi and M. R. Palacín, 17. L. Li, X. Zhao and A. Manthiram, Electrochem. Electrochem. Commun., 2013, 27, 85 Commun., 2012, 14, (1), 78 38. P. Senguttuvan, G. Rousse, V. Seznec, J.-M. 18. L. Li and A. Manthiram, J. Mater. Chem. A, 2013, 1, Tarascon and M. R. Palacín, Chem. Mater., 2011, (16), 5121 23, (18), 4109 19. T. Maiyalagan, K. A. Jarvis, S. Therese, P. J. Ferreira 39. G. Rousse, M. E. Arroyo-de Dompablo, P. Senguttuvan, and A. Manthiram, Nature Commun., 2014, 5, 3949 A. Ponrouch, J.-M. Tarascon and M. R. Palacín, Chem. 20. M. J. Trahan, Q. Jia, S. Mukerjee, E. J. Plichta, M. Mater., 2013, 25, (24), 4946 A. Hendrickson and K. M. Abraham, J. Electrochem. 40. A. Ponrouch, R. Dedryvère, D. Monti, A. E. Demet, Soc., 2013, 160, (9), A1577 J. M. Ateba Mba, L. Croguennec, C. Masquelier, P. 21. D.-H. Han, B.-S. Kim, S.-J. Choi, Y. Jung, J. Kwak and Johansson and M. R. Palacín, Energy Environ. Sci., S.-M. Park, J. Electrochem. Soc., 2004, 151, (9), E283 2013, 6, (8), 2361 22. N. S. A. Manan, L. Aldous, Y. Alias, P. Murray, L. J. 41. M. Bianchini, N. Brisset, F. Fauth, F. Weill, E. Elkaim, Yellowlees, M. C. Lagunas and C. Hardacre, J. Phys. E. Suard, C. Masquelier and L. Croguennec, Chem. Chem. B, 2011, 115, (47), 13873 Mater., 2014, 26, (14), 4238 23. L. Chen and L. L. Shaw, J. Power Sources, 2014, 42. K, Chihara, A. Kitajou, I. D. Gocheva, S. Okada and 267, 770 J.-i. Yamaki, J. Power Sources, 2013, 227, 80 24. D. Bresser, S. Passerini and B. Scrosati, Chem. 43. M. Bianchini, J. M. Ateba-Mba, P. Dagault, E. Bogdan, Commun., 2013, 49, (90), 10545 D. Carlier, E. Suard, C. Masquelier and L. Croguennec, 25. H. Yao, G. Zheng, P.-C. Hsu, D. Kong, J. J. Cha, W. J. Mater. Chem. A, 2014, 2, (26), 10182 Li, Z. W. Seh, M. T. McDowell, K. Yan, Z. Liang, V. K. 44. M.-H. Kim, H.-S. Shin, D. Shin and Y.-K. Sun, J. Power Narasimhan and Y. Cui, Nature Commun., 2014, 5, 3943 Sources, 2006, 159, (2), 1328 26. Z. W. Seh, W. Li, J. J. Cha, G. Zheng, Y. Yang, M. 45. Y.-K. Sun, S.-T. Myung, B.-C. Park, J. Prakash, T. McDowell, P.-C. Hsu and Y. Cui, Nature Commun., I. Belharouak and K. Amine, Nature Mater., 2009, 2013, 4, 1331 8, (4), 320

46. Y.-K. Sun, Z. Chen, H.-J. Noh, D.-J. Lee, H.-G. Jung, 57. L. E. Downie and J. R. Dahn, J. Electrochem. Soc., Y. Ren, S. Wang, C. S. Yoon, S.-T. Myung and K. 2014, 161, (12), A1782 Amine, Nature Mater., 2012, 11, (11), 942 58. L. E. Downie, K. J. Nelson, R. Petibon, V. L. Chevrier 47. K. Araki, N. Taguchi, H. Sakaebe, K. Tatsumi and Z. and J. R. Dahn, ECS Electrochem. Lett., 2013, 2, (10), Ogumi, J. Power Sources, 2014, 269, 236 A106 48. G. Rousse and J. M. Tarascon, Chem. Mater., 2014, 59. C. Yada and C. Brasse, ATZelektronik, 2014, 9, (3), 20 26, (1), 394 60. K.-H. Choi, S.-J. Cho, S.-H. Kim, Y. H. Kwon, J. Y. Kim 49. M. Sathiya, G. Rousse, K. Ramesha, C. P. Laisa, and S.-Y. Lee, Adv. Funct. Mater., 2014, 24, (1), 44 H. Vezin, M. T. Sougrati, M.-L. Doublet, D. Foix, D. 61. S.-Y. Lee, K.-H. Choi, W.-S. Choi, Y. H. Kwon, H.-R. Gonbeau, W. Walker, A. S. Prakash, M. Ben Hassine, Jung, H.-C. Shin and J. Y. Kim, Energy Environ. Sci., L. Dupont and J.-M. Tarascon, Nature Mater., 2013, 2013, 6, (8), 2414 12, (9), 827 62. L. Jin, P. C. Howlett, J. M. Pringle, J. Janikowski, M. 50. F. Martinez-Julian, A. Guerrero, M. Haro, J. Bisquert, Armand, D. R. MacFarlane and M. Forsyth, Energy D. Bresser, E. Paillard, S. Passerini and G. Garcia- Environ. Sci., 2014, 7, (10), 3352 Belmonte, J. Phys. Chem. C, 2014, 118, (12), 6069 63. M. Forsyth, T. Chimdi, A. Seeber, D. Gunzelmann and 51. D. Bresser, F. Mueller, M. Fiedler, S. Krueger, R. P. C. Howlett, J. Mater. Chem. A, 2014, 2, (11), 3993 Kloepsch, D. Baither, M. Winter, E. Paillard and S. 64. S. A. Mohd Noor, P. C. Howlett, D. R. MacFarlane and Passerini, Chem. Mater., 2013, 25, (24), 4977 M. Forsyth, Electrochim. Acta, 2013, 114, 766 52. D. Bresser, E. Paillard, E. Binetti, S. Krueger, M. 65. E. I. Izgorodina, D. Golze, R. Maganti, V. Armel, M. Striccoli, M. Winter and S. Passerini, J. Power Taige, T. J. S. Schubert and D. R. MacFarlane, Phys. Sources, 2012, 206, 301 Chem. Chem. Phys., 2014, 16, (16), 7209 53. Y. He, X. Yu, G. Li, R. Wang, H. Li, Y. Wang, H. Gao 66. Y. Tominaga and K. Yamazaki, Chem. Commun., and X. Huang, J. Power Sources, 2012, 216, 131 2014, 50, (34), 4448 54. J. Xia, N. N. Sinha, L. P. Chen, G. Y. Kim, D. J. Xiong 67. S. Feng, D. Shi, F. Liu, L. Zheng, J. Nie, W. Feng, and J. R. Dahn, J. Electrochem. Soc., 2014, 161, X. Huang, M. Armand and Z. Zhou, Electrochim. Acta, (1), A84 2013, 93, 254 55. S. R. Li, N. N. Sinha, C. H. Chen, K. Xu and J. R. 68. R. Bouchet, S. Maria, R. Meziane, A. Aboulaich, Dahn, J. Electrochem. Soc., 2013, 160, (11), A2014 L. Lienafa, J.-P. Bonnet, T. N. T. Phan, D. Bertin, 56. A. J. Smith, J. C. Burns, D. Xiong and J. R. Dahn, J. D. Gigmes, D. Devaux, R. Denoyel and M. Armand, Electrochem. Soc., 2011, 158, (10), A1136 Nature Mater., 2013, 12, (5), 452

The Reviewers

Mario Joost obtained his Diploma and PhD in physical chemistry from the University of Münster, Germany. He spent a postdoctoral year at the Münster Electrochemical Energy Technology (MEET) battery research centre before joining the battery materials research team at the Johnson Matthey Technology Centre, Sonning Common, UK, in 2013. His current research is focused on the development of novel electrolytes for next generation battery systems, including Li-air and Li-sulfur.

Sam Alexander obtained a Masters degree in Chemistry from the University of Shefﬁ eld, UK, before completing a PhD in Materials Chemistry at University College London, UK, in 2012, focusing on solid state synthesis of complex metal oxides. Subsequently he joined the Johnson Matthey Technology Centre, Sonning Common, in 2012. His current research is focused on the development of high energy cathode materials for Li-ion batteries.

Development of Low Temperature Three-Way Catalysts for Future Fuel Efﬁ cient Vehicles

Novel alumina/ceria/zirconia mixed oxide with improved thermal stability and oxygen storage capacity enhances low temperature performance of three-way catalysts

By Hai-Ying Chen* and Hsiao-Lan (Russell) Chang Many factors can inﬂ uence the low-temperature Johnson Matthey Inc, Emission Control Technologies, performance of a TWC. Among them, the nature of the 456 Devon Park Drive, Wayne, Pennsylvania, 19087, support materials for the platinum group metals (pgms)

USA plays a critical role (3–5). Ceria/zirconia (CeO2/ZrO2) mixed oxides have become an essential component *Email: [email protected] in a TWC because of their unique oxygen storage

and release properties. CeO2/ZrO2 mixed oxides not only enhance the intrinsic catalytic activity of the pgm Introduction components, but also provide oxygen storage capacity (OSC) to the system, minimising the air:fuel ratio Three-way catalysts (TWCs) have been widely deviation from the stoichiometric point; both signifi cantly applied on stoichiometric-burn gasoline engine improve the TWC performance of the system. Most powered vehicles to reduce the tailpipe emissions commercially available CeO2/ZrO2 mixed oxides lose of hydrocarbons (HC), carbon monoxide (CO) their surface area considerably after high-temperature and nitrogen oxides (NOx). A conventional TWC exposure. As a result, even though a fresh TWC can can convert the three pollutants at nearly 100% exhibit excellent catalytic activity below 400ºC, much conversion effi ciency once it reaches its operation of the low-temperature performance is lost when the temperature, typically above 400ºC. As the exhaust catalyst is aged. temperature can rapidly exceed 400ºC on current In this study, we developed a novel alumina/ceria/ gasoline engines, all gasoline vehicles produced zirconia Al2O3/CeO2/ZrO2 mixed oxide that shows today are capable of meeting the stringent much improved thermal stability compared to a government emission standards in the USA. conventional CeO2/ZrO2 mixed oxide with a similar Starting in 2017, US federal regulations will mandate a composition, exhibits higher OSC especially at low signifi cant improvement in fuel economy and reduction temperatures and reduces the light-off temperature of greenhouse gases (GHG) for light duty vehicles (1, 2) by nearly 50ºC. at the same time as continued reductions of tailpipe pollutant emissions. Advanced engines and powertrain Experimental systems with improved fuel effi ciency can reduce CO 2 Catalyst preparation emissions substantially, but the exhaust temperature of these systems is expected to be much lower and A novel Al2O3/CeO2/ZrO2 mixed oxide was can be below the normal operation temperature of a developed in-house. The material was prepared by a conventional TWC. This poses signifi cant challenges to co-precipitation method. For comparison purposes, a the emission control system, demanding the catalysts conventional CeO2/ZrO2 mixed oxide was prepared to function at low temperatures. following the same co-precipitation method, then

blended with γ-Al2O3 powder. Pd-loaded catalyst is not surprising that neither of the two catalysts show powders were made by impregnating Pd onto the appreciable NOx conversion in these tests. In a fully

Al2O3/CeO2/ZrO2 mixed oxide and the formulated TWC, a separate Rh component will be (Al2O3 + CeO2/ZrO2) mixture, respectively. The Pd incorporated into the formulation to enhance the NOx loading was 1 wt% in both samples. Fully formulated performance. Nevertheless, the Al2O3/CeO2/ZrO2 TWCs were prepared using the Al2O3/CeO2/ZrO2 mixed oxide supported Pd catalyst is clearly more mixed oxide and the (Al2O3 + CeO2/ZrO2) mixture, active than the (Al2O3 + CeO2/ZrO2) mixture supported respectively, as the Pd support. Full experimental Pd catalyst and is therefore considered more suitable details and characterisation data are published for applications with low exhaust temperatures. elsewhere (6). To understand why the Al2O3/CeO2/ZrO2 mixed oxide supported catalyst has better light-off activity, Results the 1050ºC/36 h redox aged powder catalysts were analysed by transmission electron microscopy (TEM). Light-off Activity of Palladium Catalysts The dark ﬁ eld images together with the elemental Supported on Al2O3/CeO2/ZrO2 Mixed Oxide images of Ce and Pd are shown in Figure 2.

The Al2O3/CeO2/ZrO2 mixed oxide and the Comparing the two dark ﬁ eld images in combination (Al2O3 + CeO2/ZrO2) mixture were evaluated as support with the Ce elemental images, it is apparent that the materials for Pd. The Pd-impregnated catalysts were CeO2/ZrO2 mixed oxide particles on the Al2O3/CeO2/ redox aged at 1050ºC for 36 hours prior to the tests. ZrO2 sample are about one order of magnitude smaller Light-off activity of the aged catalysts was measured than the CeO2/ZrO2 mixed oxides in the (Al2O3 + CeO2/ in a gas mixture containing a stoichiometric amount of ZrO2) sample. The elemental images of Pd further HC/CO/NO/O2 without perturbation and the results are indicate that high Pd dispersion is maintained on the plotted in Figure 1. 1050ºC/36 h redox aged Al2O3/CeO2/ZrO2 sample, The Al2O3/CeO2/ZrO2 mixed oxide supported Pd whereas noticeable Pd sintering has occurred on the catalyst shows rapid light-off for HC/CO and reaches (Al2O3 + CeO2/ZrO2) sample as evidenced by the two 100% conversion at temperatures above 320ºC. large Pd particles in the image.

As a comparison, the (Al2O3 + CeO2/ZrO2) mixture The results above suggest that depositing CeO2/ZrO2 supported Pd catalyst shows more gradual HC/CO mixed oxides directly on alumina supports can minimise light-off, and does not reach 100% conversion until the sintering of the CeO2/ZrO2 mixed oxides, hence the temperature goes above 390ºC. As Pd catalysts are in general relatively inactive for NOx reduction, it

(a)

100

80 Al2O3/CeO2/ZrO2 C3H6 30 nm Ce Pd Al2O3 + CeO2/ZrO2 C3H6 60 Al2O3/CeO2/ZrO2 CO Al2O3 + CeO2/ZrO2 CO (b) 40 Al2O3/CeO2/ZrO2 NO Al2O3 + CeO2/ZrO2 NO Conversion, % 20 200 nm Ce Pd 0 150 250 350 450 550 Fig. 2. TEM images of the Al2O3/CeO2/ZrO2 mixed oxide Temperature, ºC and the (Al2O3 + CeO2/ZrO2) mixture supported Pd catalysts

Fig. 1. Light-off activity of the Al2O3 /CeO2/ZrO2 mixed oxide after 1050ºC/36 h redox ageing: (a) Al2O3/CeO2/ZrO2 and the (Al2O3 + CeO2/ZrO2) mixture supported Pd catalysts supported Pd catalyst; (b) (Al2O3 + CeO2/ZrO2) supported after 1050ºC/36 h redox ageing Pd catalyst

65 © 2015 Johnson Matthey http://dx.doi.org/10.1595/205651315X686011 Johnson Matthey Technol. Rev., 2015, 59, (1) improving their thermal stability and OSC properties. results on the supported Pd powder catalysts. Both

The material can also maintain Pd in high dispersion demonstrate that the Al2O3/CeO2/ZrO2 mixed oxide even after severe ageing. All these features contribute developed in this study can offer signiﬁ cant advantages to the superior light-off activity of the Al2O3/CeO2/ZrO2 for applications with low exhaust temperatures. supported Pd catalyst.

Engine Dynamometer Evaluation of TWC Vehicle Evaluation of TWC Systems Based on the Al2O3/CeO2/ZrO2 Mixed Oxide Supported on the Al2O3/CeO2/ZrO2 Mixed Oxide

A TWC was formulated using the Al2O3/CeO2/ZrO2 A 2010 model year vehicle equipped with an advanced mixed oxide as the Pd support in combination with a Rh 3.5 l GTDI engine and a turbo charger was selected component. As a reference, a conventional TWC using to evaluate the performance of a TWC system based the (Al2O3 + CeO2/ZrO2) mixture as the Pd support on the Al2O3/CeO2/ZrO2 mixed oxide. Compared and the same Rh component was also prepared. Both to other vehicles in the same class with traditional catalysts were coated on ceramic monolith substrates naturally aspirated engines, this vehicle represents with a cell density of 62 cells cm–2 and a wall thickness approximately 20% better fuel efﬁ ciency and 15% of 64 m (or 400 cpsi and 2.5 mil). The dimension reduction of GHG emissions. As a result, the exhaust of the substrates is 10.6 cm in diameter and 7.8 cm temperature of the vehicle is also substantially lower. in length. The pgm loadings of the catalysts were Catalyst systems with either the Al2O3/CeO2/ZrO2 –1 kept at relatively low levels (1.34 g l Pd and 0.07 g mixed oxide or the (Al2O3 + CeO2/ZrO2) mixture as the l–1 Rh) to better differentiate their performance. The Pd support were evaluated. Prior to vehicle evaluation, catalysts were aged on a 4.6 l gasoline engine under the TWC systems were aged under 4-mode conditions 4-mode conditions for 100 hours with the catalyst bed to simulate the end of their useful life performance. temperatures averaging 925ºC. The aged catalysts The non-methane hydrocarbon (NMHC) and NOx were evaluated on a separate 4.6 l gasoline engine emissions of the aged systems under federal test that was capable of changing the air-to-fuel ratio from procedure (FTP) testing cycles are summarised in 13.5 to 15.5 with a perturbation frequency of 1 Hz and Table II. While the two systems show comparable NOx amplitude of 0.5. The CO/NOx crossover conversion performance, the Al2O3/CeO2/ZrO2 mixed oxide based and the corresponding HC conversion measured at system clearly demonstrates better HC conversion and a space volume of 112,000 h–1 at 400ºC and 350ºC 7 mg mile–1 lower NMHC emissions from the tailpipe. are summarised in Table I. At 400ºC, both catalysts achieve high NOx/CO/HC conversions. At 350ºC, the Table II. NMHC/NOx Emissions under FTP Al2O3/CeO2/ZrO2 mixed oxide supported catalyst still Testing Cycles on a Vehicle with a 3.5 l GTDI maintains high NOx/CO/HC conversion efﬁ ciency. Engine The (Al2O3 + CeO2/ZrO2) mixture supported catalyst, –1 –1 however, is nearly inactive. TWC systems NMHC (g mile ) NOx (g mile )

Table I. Engine Sweep CO/NOx Crossover Al2O3/CeO2/ZrO2 0.021 0.034 mixed oxide Conversion (%) and the Corresponding HC (Al O + CeO / 0.028 0.036 Conversion (%) at 400°C and 350°C 2 3 2 ZrO2) mixture 400°C 350°C Pd:Rh TWC CO/NOx, THC, CO/ THC, The cumulative tailpipe total HC (THC) emissions % % NOx, % % of the two systems during the cold start period are Al2O3/CeO2/ 81 84 51 55 shown in Figure 3. The majority of the THC is emitted ZrO 2 in the initial 250 seconds while the temperature of the (Al O + CeO / 70 82 9 10 2 3 2 catalyst system is warming up. During this period, the ZrO2) Al2O3/CeO2/ZrO2 mixed oxide based TWC system has The engine dynamometer evaluation results on fully approximately 25% lower tailpipe HC emissions than formulated TWCs are in line with the laboratory reactor the (Al2O3 + CeO2/ZrO2) mixture based system.

This article is an abridged form of a full paper presented 0.04 200 at the Society of Automotive Engineers (SAE) in 2014, –1 Al2O3/CeO2/ZrO2 Scheduled vehicle speed, mph and is published with the permission of the SAE (6). Al2O3 + CeO2/ZrO2 0.03 Vehicle speed 150 References

1. ‘LEV III and Tier 3 Exhaust Emission Control 0.02 100 Technologies for Light-Duty Gasoline Vehicles’, Manufacturers of Emission Controls Association, Arlington, Virginia, USA, April 2013 0.01 50 2. ‘EPA and NHTSA Set Standards to Reduce Greenhouse Gases and Improve Fuel Economy Cumulative tailpipe THC, g mile Cumulative tailpipe 0 0 0 100 200 300 400 500 for Model Years 2017–2025 Cars and Light Time, s Trucks’, Regulatory Announcement, United Fig. 3. Cumulative total THC emissions during the cold start States Environmental Protection Agency, Ofﬁ ce of period of FTP 75 testing cycles Transportation and Air Quality, Washington, DC, USA, August 2012 3. P. Andersen and T. Ballinger, ‘Improvements in Pd:Rh Conclusions and Pt:Rh Three Way Catalysts’, SAE Technical Paper

A novel Al2O3/CeO2/ZrO2 mixed oxide was developed 1999-01-0308, 1999 in this study. Compared to a conventional CeO2/ZrO2 4. E. Rohart, S. Verdier, H. Takemori, E. Suda and K. mixed oxide that has the same composition, the Al2O3/ Yokota, ‘High OSC CeO2/ZrO2 Mixed Oxides Used as CeO /ZrO mixed oxide is thermally more stable and 2 2 Preferred Metal Carriers for Advanced Catalysts’, SAE exhibits much improved OSC properties especially at Technical Paper 2007-01-1057, 2007 low temperatures. As a support material for Pd, the 5. Y. Hirasawa, K. Katoh, T. Yamada and A. Kohara, material improves the light-off activity of the catalyst. TWC formulations based on the new material show ‘Study on New Characteristic CeO2-ZrO2 Based noticeable advantages on a fuel-efﬁ cient vehicle with Material for Advanced TWC’, SAE Technical Paper low exhaust temperatures. Future optimisation of 2009-01-1078, 2009 catalyst systems will enable fuel-efﬁ cient gasoline 6. H.-L. Chang, H.-Y. Chen, K. Koo, J. Rieck and P. engine powered vehicles to meet stringent government Blakeman, ‘Gasoline Cold Start Concept (gCSC™) standards both for the criteria pollutant and the GHG Technology for Low Temperature Emission Control’, emissions. SAE Technical Paper 2014-01-1509, 2014

The Authors

Dr Hai-Ying Chen is a Product Development Manager at Emission Control Technologies, Johnson Matthey Inc, USA. He obtained his BSc and PhD in Chemistry from Fudan University, Shanghai, China. Following this he was a Postdoctoral Fellow at the Center for Catalysis and Surface Science, Northwestern University, Evanston, Illinois, USA. Since joining Johnson Matthey in 2000 he has been working extensively on the development of catalysts for emissions control.

Hsiao-Lan (Russell) Chang received his PhD in Materials Science from Drexel University, Philadelphia, USA. He is currently a Staff Scientist at Emission Control Technologies, Johnson Matthey Inc, USA. Since joining Johnson Matthey in 1999, his main responsibility is to develop new materials for catalyst applications on exhaust emissions control.

Johnson Matthey Highlights

A selection of recent publications by Johnson Matthey R&D staff and collaborators

EMISSION CONTROL TECHNOLOGIES 650ºC must be applied periodically to regenerate the diesel particulate fi lter (DPF). At lower temperatures ‘Solid State Platinum Speciation from X-ray Absorption (200ºC–300ºC), Cu/zeolite catalysts are more active Spectroscopic Studies of Fresh and Road Aged Three than alternative Fe/zeolite SCR catalysts. The Way and Diesel Vehicle Emission Control Catalysts’ chemistry and functionality of this class of catalyst T. I. Hyde and G. Sankar, in “Platinum Metals in the is discussed in this book chapter, along with the Environment”, eds. F. Zereini and C. L. S. Wiseman, deactivation mechanisms of previous generations Environmental Science and Engineering, Springer- of Cu/zeolite catalysts, the development of small- Verlag Berlin, Heidelberg, Germany, 2015, pp. 289–308, pore zeolite supported Cu SCR catalysts and recent ISBN: 978-3-662-44558-7 (Print); 978-3-662-44559-4 literature studies on the understanding of their (Online) hydrothermal stability and performance. A series of studies were carried out in a variety of locations in Europe and North America on fresh and FINE CHEMICALS: CATALYSIS AND CHIRAL road-aged automotive catalysts. Platinum L3 and L2 TECHNOLOGIES edge X-ray absorption spectroscopy (XAS) was used Halotriazolium Axle Functionalised [2]Rotaxanes for alongside detailed laboratory based characterisation. Anion Recognition: Investigating the Effects of Halogen- X-ray absorption near edge structure (XANES) Bond Donor and Preorganisation was found not suffi cient to determine the nature of Pt species present in multi-component catalysts. J. M. Mercurio, R. C. Knighton, J. Cookson and P. D. Therefore detailed analysis of the extended X-ray Beer, Chem. Eur. J., 2014, 20, (37), 11740 absorption fi ne structure (EXAFS) was performed Three novel halogen-bonding 5-halo-1,2,3-triazolium at the Pt L3 and L2 edges and this revealed mainly axle containing [2]rotaxanes were prepared by oxidic species to be present in the fresh catalysts, anion-templated synthesis. Different halogen-bond while metallic and bimetallic components were the donor atoms and the degree of inter-component dominant species in the road aged catalysts. Taken preorganisation affected the anion-recognition together, with the addition of Cl K-edge XANES properties of the interlocked host. This knowledge is analysis, it is concluded that no environmentally vital for designing a potent anion receptor. Bromide signifi cant quantities of chloroplatinate species were was found to be the most effective template from present in the fresh or road-aged samples. the investigation into the ability of bromotriazolium ‘Cu/Zeolite SCR Catalysts for Automotive Diesel NOx motif to direct the halide-anion templated assembly Emission Control’ of interpenetrated [2]pseudorotaxanes. The fi rst bromotriazolium axle containing [2]rotaxane was H.-Y. Chen, in “Urea-SCR Technology for deNOx After synthesised by bromine anion templation and the Treatment of Diesel Exhausts”, eds. I. Nova and E. anion-binding properties were analysed by 1H NMR Tronconi, Fundamental and Applied Catalysis, Springer, spectroscopic titration. The results showed an New York, USA, 2014, pp. 123–147, ISBN: 978-1-4899- enhanced bromide and iodide recognition relative to a 8070-0 (Print); 978-1-4899-8071-7 (Online) hydrogen-bonding protic triazolium rotaxane analogue. The use of Cu/zeolite catalysts for the selective Two halogen-bonding [2]rotaxanes with bromo- and catalytic reduction (SCR) of NOx with NH3 is iodotriazolium motifs arranged into shortened axles reviewed. Cu/zeolite SCR catalysts exhibit higher designed to extend inter-component preorganisation NOx conversion effi ciency than titania supported were also prepared and the rotaxanes were able vanadia SCR catalysts, and are also more tolerant to bind halide anions even more strongly with the to high temperature excursions. This is crucial for iodotriazolium axle integrated rotaxane capable of automotive applications, in which temperatures above recognising halides in aqueous solvent media.

Synthesis and Catalytic Applications of an Extended Hardeman, Y. Guo, E. Wright, D. Oakes, S. Hofmann Range of Tethered Ruthenium(II)/η6-Arene/Diamine and J. Robertson, Carbon, 2014, 75, 327 Complexes Direct growth is the most promising method for incorporating R. Hodgkinson, V. Jurčík, A. Zanotti-Gerosa, H. G. carbon nanotubes (CNTs) into a composite matrix to take Nedden, A. Blackaby, G. J. Clarkson and M. Wills, advantage of their high tensile strength and surface area Organometallics, 2014, 33, (19), 5517 to volume ratio for use as nanoscale reinforcement in Novel enantiopure Ru(II) complexes were prepared by hierarchical carbon fi bre–CNT composites and fuel cell introducing a tethering group between the 6-arene and electrodes. In this study, CNTs were grown into ‘forests’ up η 2 3 chiral diamine. An increase in stability and activity at lower to 0.2 mm high on an 85:15 sp :sp carbon support with Fe catalyst loadings was shown by the complexes and was catalyst. The catalyst was pretreated in inert atmosphere to tested in the asymmetric reduction of various ketones. avoid the growth of defective CNTs. Graphite, tetrahedral The presence of bulky sulfonyl groups can infl uence the amorphous carbon and pure diamond were also found to reactivity and enantioselectivity of the catalysts. produce defective CNTs. The importance of the substrate in controlling the growth of CNTs on carbon fi bres has The Infl uence of the Hubbard U Parameter in Simulating been emphasised. the Catalytic Behaviour of Cerium Oxide Degradation Mechanisms of Platinum Nanoparticle L. J. Bennett and G. Jones, Phys. Chem. Chem. Phys., Catalysts in Proton Exchange Membrane Fuel Cells: 2014, 16, (39), 21032 The Role of Particle Size The localisation of f-electrons and the self-interaction K. Yu, D. J. Groom, X. Wang, Z. Yang, M. Gummalla, error linked with DFT can affect the theoretical treatment S. C. Ball, D. J. Myers and P. J. Ferreira, Chem. Mater., of ceria. These errors are commonly corrected by 2014, 26, (19), 5540 DFT + U when investigating specifi c physical material Morphological changes in the Pt nanoparticle catalysts properties. However, rectifying certain bulk properties during fuel cell operation, particularly in the cathode, are may not lead to the correct description of catalytic associated with performance degradation. This article reactivity at surfaces due to the empirical nature of the U presents the fi rst systematic study by transmission correction. A new method for choosing the U parameter electron microscopy (TEM) analysis of the infl uence of using adsorption properties was proposed in this study. nanoparticle size on active degradation mechanisms The combination of derived ceria energetics with those and hence on the electrochemical performance of of adsorption at metal surfaces enables the construction membrane electrode assemblies (MEAs). Five MEAs of transition metal-oxide pairings and a redox screening with different average sizes of Pt nanoparticles in the model for catalysis can be developed. cathode were analysed before and after potential cycling (see Figure). In most cases, the smallest initial particle NEW BUSINESS DEVELOPMENT size catalysts ended up with the largest particle sizes Water-Splitting Electrocatalysis in Acid Conditions after 10,000 cycles, meaning that the ECA loss for Pt Using Ruthenate-Iridate Pyrochlores nanoparticle catalysts with smaller initial sizes (2.2 nm and 3.5 nm) was greater than for particles with sizes from 5.0 K. Sardar, E. Petrucco, C. I. Hiley, J. D. B. Sharman, P. nm to 11.3 nm. Mechanisms for the particle size changes P. Wells, A. E. Russell, R. J. Kashtiban, J. Sloan and R. are discussed. I. Walton, Angew. Chem. Int. Ed., 2014, 53, (41), 10960 Hydrothermal synthesis was used to prepare for the fi rst time a series of conducting mixed ruthenium–iridium d = 10.3 nm A2B2O7 pyrochlore materials with A = Na, Ce(IV) and B = Ru(IV), Ir(IV) as nanocrystalline powders. A solid solution of pyrochlore was used as a catalyst layer for the electrochemical evolution of oxygen from water at pH <7. The new composition produces electrode coatings with better charge densities than a typical (Ru,Ir)O2 catalyst. The catalyst was studied in situ using XANES. There was no evidence for Ru or Ir in oxidation states +6 or higher. Both Ru and Ir were shown to contribute to the electrocatalytic activity. 10 nm After cycling

NEW BUSINESSES: FUEL CELLS Reprinted with permission from K. Yu, D. J. Groom, X. Wang, The Role of the sp2:sp3 Substrate Content in Carbon Z. Yang, M. Gummalla, S. C. Ball, D. J. Myers and P. J. Supported Nanotube Growth Ferreira, Chem. Mater., 2014, 26, (19), 5540. Copyright (2014) American Chemical Society R. J. Cartwright, S. Esconjauregui, R. S. Weatherup, D.

Record Activity and Stability of Dealloyed Bimetallic Insights into Brønsted Acid Sites in the Zeolite Mordenite Catalysts for Proton Exchange Membrane Fuel Cells D. B. Lukyanov, T. Vazhnova, N. Cherkasov, J. L. Casci B. Han, C. E. Carlton, A. Kongkanand, R. S. Kukreja, and J. J. Birtill, J. Phys. Chem. C, 2014, 118, (41), 23918 B. R. Theobald, L. Gan, R. O’Malley, P. Strasser, F. T. The purpose of this study was to identify the exact number Wagner and Y. Shao-Horn, Energy Environ. Sci., 2015, and locations of Brønsted acid sites (BAS) in acidic and doi:10.1039/C4EE02144D partially Na-exchanged samples of zeolite mordenite The highest catalyst activity and device durability (MOR). The catalytic properties of MOR are notably yet achieved in PEMFCs under automotive testing infl uenced by the local environment of the BAS (O1– conditions is reported. A family of dealloyed core-shell O10 atoms), see Figure. At least six distinct BAS in the MOR structure were identifi ed by a comprehensive FT-IR Pt-Ni nanoparticles were developed as catalysts for investigation and Fourier self-deconvolution (FSD) analysis the cathode. Smaller particle size, non-oxidative acid of the IR spectra. The results showed that ~25% of BAS treatment and post-acid-treatment annealing was are located in the eight-membered ring (8-MR) channels found to reduce transition metal leaching from catalyst (O1–H and O9–H) in the purely acidic H-MOR sample, nanoparticles, and suppress nanoporosity formation. ~13% of BAS are found at the intersections between This insight led to the ability to design more stable and the side pockets and 12-MR channels (O5–H hydroxyls) active Pt-Ni catalysts. The details of alloy structure and ~62% of BAS are located in 12-MR channels (~39% and compositions that lead to long-term PEMFC correlate to O2–H and/or O10–H hydroxyls and the device stability were analysed using SEM and EDS. remaining 23% to O3–H and O7–H hydroxyls). The acid The resulting catalyst meets and exceeds the offi cial sites were found to be distributed quite evenly between 2017 DOE targets for the oxygen reduction reaction oxygen atoms in the various crystallographic positions. (ORR).

PROCESS TECHNOLOGIES

FCC Additive Improves Residue Processing Economics O8 T1 with High Iron Feeds O7 O5 O3 T. Hochheiser, Y. Tang, M. Allahverdi and B. De Graaf, O6 O2 American Fuel and Petrochemical Manufacturers IV T4 T3 (AFPM) Annual Meeting, Orlando, USA, 23rd–25th O9 I O10 March, 2014 O1 T2 O4 Johnson Matthey’s FCC INTERCATJM additive VI CAT-AIDTM is used by many refi neries to trap contaminants due to its ability to improve the profi tability of the FCC operation. Lower quantities T atoms Oxygen atoms of fresh catalyst and fl ushing Ecat are needed and the product selectivities are improved, in particular Reprinted with permission from D. B. Lukyanov, T. diminishing delta coke. This study includes three Vazhnova, N. Cherkasov, J. L. Casci and J. J. Birtill, J. TM commercial examples and the use of CAT-AID to Phys. Chem. C, 2014, 118, (41), 23918. Copyright (2014) reduce delta coke and improve residue processing is American Chemical Society demonstrated.

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