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Chemical Storage R&D at Los Alamos National Laboratory Project ID# ST040

Tessui Nakagawa, Roshan Shrestha, Ben Davis, Himashinie Diyabalanage, Anthony Burrell, Neil Henson, Troy Semelsberger, Frances Stephens, John Gordon, Kevin Ott, Andy Sutton

2010 DOE Annual Merit Review

This presentation does not contain any proprietary or confidential information

DOE Chemical Hydrogen Storage Center Slide 1 Overview

Timeline Barriers • Weight and Volume • Start: FY 05 • Flow Rate • End: FY 10 • Energy Efficiency • 100% Complete • Cost • Regeneration Process • System Life-Cycle Assessments

Budget Partners •FY 09 - $2,750 K • Chemical Hydrogen Storage •FY 10 Center of Excellence - $ 2, 000 K • IPHE ( UK, New Zealand) • Hiroshima University, Japan

DOE Chemical Hydrogen Storage Center Slide 2 Relevance - Objectives

• Complete demonstration of regen process and provide data for preliminary cost analysis of NEW LANL regen process • Develop liquid -borane (AB) fuels and increase rate and extent of hydrogen release • Develop and demonstrate heterogeneous catalysts and continuous flow reactor operation • Identify and demonstrate new materials and strategies for near-thermoneutral hydrogen release (ΔG◦ = ideally no less negative than ca. –0.8 kcal/mol) • Develop materials and processes to minimize gas-phase impurities, and demonstrate adequate purity of hydrogen stream

DOE Chemical Hydrogen Storage Center Slide 3 Relevance - Milestones

Make recommendations of materials, release and regen processes to DOE Catalog process details and result in DOE Storage Database Preparation to pass final report and associated information along to Engineering Center Finish analysis of hydrazine regeneration route Demonstrate details of ‘one pot’ regeneration Complete impurities quantification on most promising systems (solid AB, IL(s) AB)

DOE Chemical Hydrogen Storage Center Slide 4 Approach: Los Alamos Technical Contributions

• Engineering Guided Research – Gas cell analysis of impurities in hydrogen release • Regeneration – Completed demonstration of regen – Demonstrate all individual steps to process and provided data for preliminary ammonia borane from spent fuel and cost analysis of NEW LANL regen begin process integration process – Refined stoichiometry, concentrations, separations, substitutions, reaction times, – Interfacing with Engineering CoE to materials properties etc transfer relevant materials data – Completed demonstration of regen • New hydrogen storage materials for portfolio process and provided data for preliminary – Design and synthesis of near- cost analysis of NEW LANL regen thermoneutral release materials process – Use theory to guide toward most energy – Design and synthesis of liquid fuel efficient matching of regeneration compositions reactions • Hydrogen Release – Identify reaction pathways to maximal Patents storage and release rates • – Published – 8 – Design, synthesize, and demonstrate – Pending – 8 heterogeneous catalysts with high rates – Disclosures – 6 at T < 100 °C – New Base Metal catalysts

DOE Chemical Hydrogen Storage Center Slide 5 Technical Accomplishments since last review • A complete one pot regen cycle has been proven with overall yield of spent fuel digestion through reduction steps exceeding 90%. This method works for multiple spent fuel forms including spent fuels from ionic liquids giving ammonia borane. • Cost Analysis on NEW LANL regen process underway in collaboration with DOW. LANL is providing all of the experimental data and conditions. • Liquid fuel compositions, based upon ionic liquids, have been DOWN SELECTED to continue. Development of new ionic liquid fuel compositions with greater than 10 wt% hydrogen • Heterogeneous metal catalysts for hydrogen release have been prepared and demonstrated to have high rates of release to > 9 wt % H2 • Hydrogen purity analysis system has been assembled and is operating to identify and quantify impurities in H2 stream • Preliminary analysis of filter requirements begun in collaboration with engineering center of excellence. Data indicates we need to minimize borazine production.

DOE Chemical Hydrogen Storage Center Slide 6 Ammonia Borane 20 wt% H2 But ……

3 Ammonia Borane (H3N‐BH3) → Spent fuel (B3N3H4) + 7H2↑ ΔH ≈ ‐7 kcal/mol

•Good news in that temperature necessary for fast H2 release can be obtained from heat of reaction

•Bad news in that extra cooling may be required

•Process is too exothermic to consider direct dehydrogenation (off board regeneration needed)

•Side reactions are known and accelerated by overheating (difficult to control in large volumes of solid) -Impurities * Can lead to loss of material as well as fuel cell poisons -Different spent fuel forms possible * Can complicate regeneration

DOE Chemical Hydrogen Storage Center Slide 7 Solving the Issues: Kinetics in the laboratory

Solid release rates AMR 2007 St_28 ILrelease rates AMR 2007 St_27

Thermal IL release rates AMR 2009 St_16 Catalytic release rates LANL 2009 St_17

Hydrogen release kinetics are no longer a major issue DOE Chemical Hydrogen Storage Center Slide 8 ANL analysis of ionic liquid release system ANL kinetics model fits experimental thermal release data

− /)1( nn ii αi kndtd αiii −−−= αi )]1ln()[1(/

ANL dehydrogenation kinetics model and preliminary system analysis indicate that hydrogen release rates will meet the DOE target. Heat rejection and startup/shutdown are key challenges DOE Chemical Hydrogen Storage Center 9 Slide 9 Approach – Materials Development

Materials must meet CHSCoE 2007 down select criteria 2008-09 Discovery 2009 Analysis 2009-10 Go-NoGo

• Literature search •Hydrogen release profile •Exothermic or endothermic? •Characterization •Improved release rates? • Prescreen materials •X-ray Structure •Improved release volume? •Fewer impurities? ¾ H2 Wt% must be in •Thermodynamics excess of 7% •Impurities

¾Example W(NH2BH3)6 •Feedback to discovery = 8.3 wt%

• Materials synthesis

MgCl2 + 2NaNH2BH3 → Mg(NH2BH3)2 + 2NaCl MgCl2 + NaNH2BH3 → Mg(NH2BH3)Cl + NaCl ZnCl2 + 2NaNH2BH3 → Zn(NH2BH3)2 + 2NaCl TiCl4 + 4NaNH2BH3 → Ti(NH2BH3)4 + 4NaCl LiNH2 + NH3BH3 → LiNH2BH3 + NH3

Slide 10 DOE Chemical Hydrogen Storage Center Impurities from solid AB AMR 2008 St_6

We have been looking at gas impurities for several years

DOE Chemical Hydrogen Storage Center Slide 11 2010 Quantitative Gas Analysis of Thermal Release from AB

Tonset Impurities can be detected before Ammonia (963 cm-1) ~ 70 °C major hydrogen release Diborane (720 cm-1) ~ 86 °C -1 temperatures Borazine (2550 cm ) ~ 86 °C

Pure solid ammonia borane produces large amounts of impurities.

DOE Chemical Hydrogen Storage Center Slide 12 Impurities and Mitigation (solid AB)

• Experimental Data AB/MC Borazine Production • Raw Product Stream from 0.2 mgBorazine/ mgAB/MC AB Thermal Reacted Decomposition Reaction Conditions: 30-200°C @ 5°C/min Borazine Sorption Capacity Activated Carbon (ACN-210-15): • Filtered Product 0.26 mgBorazine/ mgCarbon Stream from AB Thermal Decomposition • Carbon Sorbent Scaleup

• 5kg of H2 results in 37kg of AB/MC (2.5 moles H2/mole AB) 6.2 kg of borazine produced per fuel tank 24 kg of carbon per fuel tank

13 DOE Chemical Hydrogen Storage Center Slide 13 Center Approaches to hydrogen release: Faster rates, lower temps and cleaner hydrogen •Additives to solid AB

•Solvents plus AB

•Homogeneous catalyst

•Ionic Liquids

•Heterogeneous catalyst

•Alkyl-AB / AB mixtures for liquids

•New cyclic derivatives

•Metal ammonia

DOE Chemical Hydrogen Storage Center Slide 14 2009 Liquid Fuels based upon alkylamine boranes

H H

H3C N BH3 H3C N BH3

H3C CH3CH2

solid at RT, m.p. = 37oC liquid at RT

NH2 BH3

liquid at RT

H2N NH2

BH3 BH3 H2N NH2 solid at RT

BH3 BH3

cis/trans cyclohexane-bisAB pasty solid at RT

Last year sec-butylammine-BH3 has shown the most promise with sec-butylammine- BH3:AB 50:50 wt% mixtures liquid at below room temp.

DOE Chemical Hydrogen Storage Center Slide 15 2010 Alkyl-AB materials kinetics and impurities 100 pure SBAB pure SBAB pure SBAB 2 15 0 16 17 18 26 27 28 -20 29 30 41 42

43 44 -40 45 53 54 55 56 57 -60 58 67 87.5 mass % 68 70 72 82 -80 83 -100 50 100 50 100 50 100 Gas analysis of thermal

profile of secBuNH2BH3 indicated significant impurities at temperature greater than 50 C

DOE Chemical Hydrogen Storage Center 2010 Catalysts of Alkyl-AB – AB mixtures

TG-RGA 10%AB-SBAB 2 3 13 15 16 17 18 25 26 27 RGA 28 29 30 37 41 42 43 44 51 52 53 54 55 56 57 58 61 62 63 64 65 66 67 68 69 70 76 77 78 79 80 81 82 83 84 85

RGA(zoom)

Intensity (arb. units) 0 TG -30

-60

-90

Weight (wt%) 20 40 60 80 100 120 140 No improvements were observed in the rates of Temperature (°C) hydrogen release possibly due to poisoning from Sec- butylNH2. Gas phase impurities were significant. This approach to liquid storage systems has been halted at LANL.

DOE Chemical Hydrogen Storage Center Metal AB materials M-(NH2BH3)x

Metal-AB derivatives are now known for several metals.

DOE Chemical Hydrogen Storage Center Experimental KAB crystal structure Theoretically predicted Structure (16 f.u.) Y. Zhang and C. Wolverton, 2010 PEGS+DFT structure (2 f.u.)

Bond Expt. Theory Lengths (PEGS+ DFT) K2 K1 K1 K1-K2 4.26 4.24 K1-N 2.96 2.77 K2 K1-B 3.38 3.08 K2-N 3.01 2.81 K2-B 3.12 3.02

Space group: Pbca Space group: P1 a= 9.35 Å a= 5.54 Å b= 8.21 Å b= 7.52 Å c= 17.19 Å Progress with theory for structure prediction. c= 5.36 Å α= 90.00 α= 103.98 β= 90.00 β= 64.25 γ= 90.00 γ= 104.20 Predicted structure nearly degenerate with experimental structure (within 11 meV/f.u.) Predicted structure also has two symmetricallyDOE Chemical Hydrogen distinct Storage Center K positions, in agreement with expt. Metal AB materials

Li

Great kinetics at low temperatures, no borazine, small amounts of ammonia All materials currently known show exothermic hydrogen release. It is not possible to regenerate these materials efficiently but these materials are useful for stationary near term applications Work with these materials should continue with possibility of better thermodynamics in as yet unknown materials

DOE Chemical Hydrogen Storage Center Hydrogen Release from NH3BH3 in Ionic Liquids (ILs)

Contrasting dehydrogenation at 85 oC

Ionic liquid : AB Ionic liquid

Solid AB

Thermal IL release rates AMR 2009 St_16

Ionic liquids improve thermal kinetics of hydrogen release L. G. Sneddon, et al., J. Am. Chem. Soc., 2006, 128, 7748.

Impurities still present in hydrogen from thermal release, but no diborane!

DOE Chemical Hydrogen Storage Center Slide 21 2010 Ionic liquids and catalyst results in different reaction products Ethylcyclobutane (ECB) analog H H N 2 HB BH [M] +2AB N NH BH -3H2 + H2NBH2 H B B 2 3 -2H2 2 N H HN NH H B 2 H H H -H2 BH [M] 2 -H H2 2 B N H N NH polyborazylene or H2 2 2 H2B BH2 H H N > 2 equiv. H 2 H2 [M] BH2 +AB NH2 Cyclohexane analog -H2

H H H [M] BH2 [M] H+ H3N BH2NH2 nBH3 1 equiv. H 2 HN NH B 2 H2 DOE Chemical Hydrogen Storage Center Properties of IL:AB mixtures look promising Thermal stability of IL:AB mixtures 50 o C - no change on mass of sample or in gas above sample for over 100 hours 50 o C sample - no change on mass of sample or in gas exposed to air above sample for over 120 hours but water observed in gas. is hydroscopic

- no change on mass of sample for over 60 o C sample 120 hours but slight changes in gas above exposed to air sample

Only ammonia is observed in the gas phase at 70 C for catalyst but long term stability of samples at 60 o C still needs to be addressed

DOE Chemical Hydrogen Storage Center Slide 23 Summary – LANL Down Selects for 2010

Organic solvents currently weight % hydrogen too low - stopped

Alkyl ammonia borane materials do not show enough promise, catalyst poisoning and too much impurities in hydrogen to continue – stopped

Metal ammonia borane materials have potential but no current material is suitable for automotive applications – small scale continued support

Ionic Liquid systems with catalysts look promising but need to tailor catalyst and ionic liquids combination - continued

DOE Chemical Hydrogen Storage Center Slide 24 Approach - Off-Board Regeneration

2007-08 Discovery 2008 Demonstration 2009-10 Cost Analysis

•Literature search •Test reactions •Process conceptualization •Theory •Characterization •Flow sheet development •Scoping reactions •Scaling •Iterate w/experiments •Modeling ¾separations •Thermodynamic assessment ¾kinetics •Feedback to discovery ¾yield •Aspen •H2A Tool

Slide 25 DOE Chemical Hydrogen Storage Center Technical Accomplishments and Progress Off-Board Regeneration Required (timeline 2008-2010)

3 Ammonia Borane (H3N‐BH3) → Spent fuel (B3N3H4) + 7H2↑ 2007 – Thiol based digestion of spent fuel first ∆H ≈ ‐7 kcal/mol demonstrated (Miranda and Ceder 2007) Mid 2007 – Tin hydrides observed to form ammonia borane (AB) •Fall 2009 hydrazine Regeneration Scheme 2008 – Digestion/reduction combined into one cycle •January 2008 Full Scheme Mid 2008 – Feedback from TT, AMR increases emphasis on process analysis, cost; optimization of reactions, reducing unit operations •Work to DOW Baseline Analysis August 2008 – Center ‘Engineering Summit’ in Philadelphia with R/H •Ultimate Goal Fall/Winter 2008/2009 – Iterative process modifications with DOW input;

2010 ‐ DOW analysis of hydrazine regeneration Center of Excellence Targets: 60% process efficiency for regeneration

$2‐4 gallon of gas equivalent for H2 stored DOE Chemical Hydrogen Storage Center Complete Regen Cycle 3 LANL AMR 2009 (st_17) with cost analysis

Problem: ANL and Dow analysis indicate that

SnH reagent too massive and the CO2 compression was too energy intensive. Significant effort was expended to fix the problems

DOE Chemical Hydrogen Storage Center Slide 27 Complete Regen Cycle 4 LANL 2009 (poster)

S H N2H4 B H3N-BH3 + (H4N2)-BH3 + "B(N2H3)3" NH S 3 upto ~ 80 %

Bu3SnCl NaOH or Et3N Formic Acid HCl SH HB N N BH SH S S S SnBu3 HB N B NH4 Bu3SnOC(O)H - 2.x H2 B NH HB NH SH S S HN NB B NH3BH3 Bu SnH B N B NH 3 heat B N S H - CO2 HN B B S NH3 HB NH x

H2NNH2

Hydrazine is a light hydrogen transfer material that removed over 50% of weight, due to tin, in the regen cycle. But some tin is still required. DOE Chemical Hydrogen Storage Center Slide 28 2010 Hydrazine also reacts directly with PB

Tin is no longer required but add a amine metathesis step HB NH HN B B N B N B NH N2H4 HN NB B (H N )-BH +"B(NH ) " B NH HB NH H3N-BH3 + 4 2 3 2 3 3 HB N Heat Major N BH Product HB N x

HB N N BH HB N H2NNH2 BH3 H2NNH2 - 2.x H2 B NH NHHB + HN NB B NH3BH3 B N B NH NH3BH3 B N HN B -NH HB NH x 3 N NMe2 -N2H4

H3B N NMe2

NH3

DOE Chemical Hydrogen Storage Center Slide 29 Complete Regen Cycle 5 LANL 2010

Again theory helps select best amine for metathesis HB NH HN B

H2N N B N N2H4 H3B-NH3 NH3, 60 C H2N N BH3 NH3BH3 B N B NH - N , NH BH3-N2H4 HN NB B 2 3 -NH3 B NH HB NH HB N N BH HB N

x

DOE Chemical Hydrogen Storage Center Slide 30 Complete Regen Cycle 6 LANL 2010

HB NH HN B NH B N N2H4 H3B-NH3 3 B N B NH H3B-NH3 BH3-N2H4 HN NB B -N2,H2,NH3 o B NH NHHB X 60 C HB N N BH HB N Catalyst x

X

up to 2 eq. H2

At elevated temperature ammonia will directly convert hydrazine borane to ammonia borane

DOE Chemical Hydrogen Storage Center Slide 31 Complete Regen Cycle 7 Demonstrated for several different fuel forms LANL 2010

HB NH HN B

B N N2H4 NH3, 60 C B N B NH NH3BH3 HN NB B - N2 B NH HB NH H H HB N 2 2 B N B N BH NH 1. NH , N H H2N H2 2 3 2 4 HB N H3NBH3 H B H2 BH 2 B 2 x N N H2 H2

N N N N Cl NH3, N2H4 H3NBH3 Cl "NBH"

Ammonia can be used as the solvent in a one pot direct conversion of spent fuel to ammonia borane

DOE Chemical Hydrogen Storage Center Slide 32 Summary

To date we have demonstrated 7 complete cycles for regeneration

Regeneration of spent ammonia borane IS POSSIBLE More work is required to determine the optimal regeneration process as both catalysts and fuel form evolves

Current hydrazine synthesis relies on the Chloralkali process, requiring in significant separation (distillation, drying etc) and is therefore expensive!

2NH3 + NaClO N2H4 +HNaCl 2O+

Other processes are know in the chemical literature and some are even used commercially but as hydrazine is not used in very large quantities little effort has gone into alternative (cheaper) synthetic routes.

We need to either improve hydrazine cost or develop yet another regen scheme

DOE Chemical Hydrogen Storage Center Slide 33 LANL Materials Comparisons and Progress; Selected Results

Metrics 2005 2006 2007 2008 2009 2010

2010 2007 Ionic Liquid ABs Grav. 2010 Liquid AB AB density Metal AB’s 2010 Mixtures Metal AB’s (Mat. wt%) Metal AB’s 2010 Ionic Liquid ABs Vol. density Liquid AB (kg-H2/L) 2015 Metal AB’s Metal AB’s

NON- Minimum full NON-Platinum Platinum flow rate catalysts catalysts catalysts

Operating Temperature 70 ˚C 70 ˚C 70 C

inline filter inline filter inline filter Fuel Purity required required required

Fuel cost $7-8 1st process

DOE Chemical Hydrogen Storage Center Slide 34 CHSCoE Materials Decision Tree

Criteria for materials down selection has been adhered to by LANL

Yellow - marginally acceptable, or secondary issues e.g. impurities Green - high priority materials of exceptional promise

DOE Chemical Hydrogen Storage Center Slide 36 Collaborations

Chemicals COE

IPHE

DOE Chemical Hydrogen Storage Center Slide 37