Green Hydrogen for the Future Sustainable Growth of Human Beings

◆ Global Warming, Carbon Cycle vs. Water Cycle ◆ Green Hydrogen Energy System ◆ Water Electrolysis ◆ Polymer Electrolyte Fuel Cell

Kenichiro OTA Green Hydrogen Research Center Yokohama National University, JAPAN

CCUS and H2 International Conf.、Feb. 20th, 2020, Belle Salle Kanda, Chiyoda, Tokyo, Japan Rapid Global Warming on the Earth Green Hydrogen Research Center, Y.N.U.

5.0 4.5oC

4.0 ℃

3.0

2.0 2.0oC 1.5oC

1.0 Temp. Increase/ Temp.

0.0

-1.0

700 1000 1500 1900 2100 Year

（by IPCC 4th Report(2007) Global entropy flow for sustainable growth Green Hydrogen Research Center, YNU The earth is a closed system. Entropy production by the activity of the mankind Human society Materials circulation

Resources for Wastes from the the human society human society Solar energy Low entropy Global environment Entropy production by the activity of the global environment

Q: 1.2x1014kW Heat radiation to the space Disposal of produced entropy ΔS=4.7 x 1011 kJ/K･s Carbon cycle on the earth Green Hydrogen Research Center, YNU

Atmposphere750 (360ppm CO2) (Annual increase 3.2)

surface the from sea Emission

Changingland

surface the to sea Absorption

decomposition Respiration Photosynthesis

5.5

90 92

- Human activity use Ocean surface 1020

Fossil fuels

decomposition Respiration synthesis

1.6 Photo

Upwelling flow flow 60 61.4 0.5 12000 Sinking

Land - Vegetation 610 50 40 Soils and detritus 1580 100 91.6 Remains Excrement Intermediate and □ : Carbon storage quantity. Gt Carbon Marine biota 4 deep ocean → : Movement. Gt Carbon/year 3 38100 6 Dissolved 6 0.2 organic carbon Surface sediment 700 150 Water cycle on the earth Green Hydrogen Research Center, YNU

Vapor transport Land atmosphere 4.5 Marine atmosphere 11

43.8

Evaporation

Evaporation

Rainfall Rainfall

110.4 66.6 453.4 409.6 Reduced water Land Marine 1,400,000 Vegetation. 43.8 Snow, ice 43,400 Surface water 360 □ ; Water storage quantity. Tt water Groundwater 15,300 → ; Movement. Tt water/year Hydrogen Economy and Water Circulation Green Hydrogen Research Center, YNU

Entropy Production by Human Activity

Human Society H2+1/2O2 → H2O

H2O Heat H2 Solar Energy Low Entropy Water Circulation Earth Natural Entropy Production H2O→H2+1/2O2

Disposal of Entropy To Universe Comparison between water cycle and carbon cycle Green Hydrogen Research Center, YNU

carbon water

Total amount 54Tt 27000 Times 1,460,000Tt

Atmosphere abundance 750Gt 21Times 15.5Tt Annual movement from 152Gt/yr 496Tt/yr atmosphere 3160 Times Average retention period in 5 yaer 10 day atmosphere 180 Times Environmental Impact Factor of Carbon Green Hydrogen Research Center, YNU

EIF (Environmental Impact Factor) of Carbon

Carbon (CO2) Emission by Energy Consumption / Natural Carbon Circulation

Earth Japan

Natural Carbon Cycle 150Gt/y 0.37Gt/y

Carbon (CO2) Emission 5.5Gt/y 0.32Gt/y by Energy Consumption

EIF of Carbon 0.036 0.86

D.S.Shimel; Terrestrial ecosystems and the carbon cycle, global change biology(1995) EIF of H2 Energy Green Hydrogen Research Center, YNU

EIF (Environmental Impact Factor of Hydrogen

= (H2O through H2 Energy System) / (Natural Water Vaporization)

Earth Japan

Annual 5×1014t /y 2.3×1011t/y Vaporizaiton 10 9 H2O through H2 5×10 t/y 1.4×10 t/y Energy System

EIF of H2 ～0.0001 0.006 Dependence of EIF on Consumption Density (2004-2013） Green Hydrogen Research Center, Y.N.U. 100

10 Fossil Fuel CO2 from Energy Usage

] EIF(Fossil Fuel)= ------CO2 of Natural Circulation

1

Tokyo

Osaka

Aichi Saitama

0.1 Kanagawa

Impact Factor [ Factor Impact

Fukuoka

Ibaragi Hyogo

0.036

Ishikawa

Saga

Gifu

Shizuoka

Kumamoto Yamaguchi 0.01 Kochi H2O from Energy Usage

Hokkaido EIF(H2)= ------Enviromental H2O of Natural Circulation 0.001 Green Hydrogen

0.0001 10 100 1000

Energy Consumption Density [MJ/m2] Green Hydrogen Energy System Green Hydrogen Research Center, YNU

Renewable energy Fossil fuel Nuclear energy

Fuel cell Electric energy Hydrogen Water electrolysis

Thermal energy Power

Green Hydrogen: Hydrogen from water using renewable energy. Future of Primary Energy Green Hydrogen Research Center, YNU Fossil Energy Limited resources: ultra high efficiency for use Nuclear Energy Against earth quake and tsunami Waste treatment Safety science for nuclear usage Renewable energy Hydroelectric power Photovoltaic power Biomass energy Geothermal energy Wind power Storage and Transport of Renewable Energies Green Hydrogen Research Center, YNU

➢Storage of Electricity ◆Mechanical storage ( compressed gas, fly wheel) ◆SMES ◆Capacitor ◆Battery ◆Hydrogen (or chemical) gas, liquid, metal hydride, organic hydride ◆Pumped hydro

➢Long distance transport of electricity ◆ Liquid hydrogen ◆ Organic hydrogen (Toluene/MCH system) GW Pumped Hydro

MW

SMES

Power kW Hydrogen Battery

Capacitor W

sec min hour day month Storage Time Comparison of storage system of electric power Cost of power generation in Japan Green Hydrogen Research Center, YNU [yen/kWh]

[yen/kWh] Cost

Land Off shore Land Off shore World Japan

Cost of wind power

Cost Cost

Solar cell Biomass Small hydro Wind Geothermal LNG Power （NEDO report) Hydrogen production method Green Hydrogen Research Center, YNU Hydrogen from water ・Water electrolysis : Electricity from renewable energy . Alkaline Water Electrolysis Polymer Electrolyte Water Electrolysis. High Temperature Water Vapor Electrolysis. . ・Thermochemical process : Heat (1000 oC or lower ) of HTGR, solar heat etc. Multi-step chemical reaction ・Direct thermal decomposition : High temperature over 4000 oC. Separation at temperature. ・Photo decomposition : Photo-chemical reaction Complete decomposition using visible light is still impossible. Characteristics of Water Electroysis Green Hydrogen Research Center, YNU 1.9 固体高分子型Polymer Electrolyte Type 1.8 アルカリ型Alkaline Type 1.7

1.6

セル電圧 / Ｖ 1.5

50 ℃ Cell Cell Voltage 1.4 0 0.1 0.2 0.3 0.4 0.5Alkaline Electrolyzer Commercially available 電流密度 / Ａcｍ-2 Current Density Cheap (Fe or Ni Electrode) Polymer Electrolyte Electrolysis High Density, High Efficiency Expensive (Pt or Ir base) Polarization of Pt in Aqueous Solution Green Hydrogen Research Center, YNU 50 Theoretical 1M H2SO4 Potential of HER 1M KOH 25

2 Theoretical Potential of OER

0

/ mA cm mA / i -25

-50 0 0.5 1.0 1.5 2.0 E vs. RHE / V Critical Issue of water Electrolysis large oxygen over potential ＝＞ Voltage loss

A New Electrode Material is needed. Commercial Alkaline Water Electrolyzers in 1970s Green Hydrogen Research Center, Y.N.U.

Stuart Energy Company （Electrolyzer） ABB(BBC） Norsk Hydro De Nora IHT(Lurgi） Method Monopolar Bipolar Bipolar Bipolar Bipolar Pressure(kg/cm2) normal normal normal normal 30 Temp.(℃) 70 80 80 80 90 Electrolyte(KOH, %) 28 25 25 29 25 Current Density(A/m2) 1,340 2,000 1,750 1,500 2,000 Cell Voltage(V) 1.9 2.04 1.75 1.9 1.86 Current Efficiency(%) >99.9 >99.9 >98 98.5 98.75 Power Consumption ３ 4.9 4.9 4.9 4.6 4.5 (kWh/Nm H2)

3 3 Target： From 5 kWh/Nm H2 to 4 kWh/Nm H2 Energy change of water formation reaction(25oC) Green Hydrogen Research Center, YNU

H2(g) + 1/2O2(g)

Electrical Energy ΔGo Total Energy 237 kJ/mol ΔHo [229 kJ/mol] 286 kJ/mol

Fuel Cell Fuel [242 kJ/mol]

Heat 49 kJ/mol Water Electrolysis Water TΔSo [13 kJ/mol]

H2O(l), [H2O(g)] Temperature Dependence of Water Formation Reaction Green Hydrogen Research Center, YNU

300 1.5

Total Energy (ΔH) 1 - H2 + 1/2O2 = H2O Heat(TΔS) 200 1 Theoretical Voltage of Fuel Cell and Water Electrolysis 100 Electic Energy(ΔG） 0.5 Voltage/V Energy/kJ mol Energy/kJ Low Temp. > High Temp.

Liq. Gas 0 0 0 100 500 1000 Temp./ oC Theoretical Efficiency of Fuel Cell vs Carnot Efficiency Green Hydrogen Research Center, YNU

100 o εF = ΔG(T)／ΔH (298) (HHV) 80

εＣ＝（ＴＨ－ＴＬ）／ＴＨ / % / 60

Fuel Cell: F Fuel Cells 40 PEFC: Room Temp.～120℃

Effciency AFC:Room Temp.～200℃ ～ 20 Carnot Eff,: C PAFC:120 200℃ MCFC:600～650℃ SOFC:600～800℃ 0 200 500 1000 1500 2000 Temp. / K Polymer Electrolyte Fuel Cell (PEFC) Green Hydrogen Research Center, YNU

Characteristics H O +H O 2 2 2 cathode ⚫ High power density e- ⚫ Low operation temperature

Applications H O 2 ⚫Co-generation system (CHP) H H+ - 2 e ⚫ Fuel Cell Vehicle O2 ⚫ Mobile power source Major technical issues ⚫ Cost down anode H2 gas O2 gas ⚫Improvement of performance

polymer electrolyte 23 1 kW PEFC at my home (2005.7.09 - ) Green Hydrogen Research Center, YNU 1 kW home cogeneration system The commercialization started in 2009. Over 300,000 units are operating in Japan. Capacity 1 kW – 700 W Hot water (60oC, 200 L) Daily Start and Stop

without N2 purge (Hot water oriented mode) Life > 10 years The cost target: 7,000 US$/unit in 2020.

1.0 0.9 Month CO2 CO2 0.8 0.7 Reduction Reduction 0.6 kg-CO2 % 0.5 0.4 Jan 17.5 11.5 0.3 0.2 0.1 Feb 38.3 21.6 0.0

Mar 41.8 21.9 24

2005/8/25 0:00 2005/8/25 2:00 2005/8/25 4:00 2005/8/25 6:00 2005/8/25 8:00 2005/8/25

2005/8/25 10:00 2005/8/25 12:00 2005/8/25 14:00 2005/8/25 16:00 2005/8/25 18:00 2005/8/25 20:00 2005/8/25 22:00 2005/8/25 FCVs in Japan Green Hydrogen Research Center, YNU

Compressed H2 gas ( 70 MPa) Driving Range > 650 km Life > 10 years (5000 h) Cold start at - 30oC Output Power: 3 – 3.5 kW/L NEDO’s new target is 9 kW/L in 2040. Commercialization has started in 2014.

Target 200,000 FCVs with 320 H2 Stations in 2025. 1st Hydrogen Fuel Cell Vehicle in Japan (1988) Green Hydrogen Research Center, YNU

30

25

V

/

E H2-O2 20 25% H2SO4 39 st acks ( 100cm2x39) 44. 2℃

15 0 10 20 30 40 50 60 70 I /A

2 1.1 kW, H2/O2-100cm x39 cells Sulfuric Acid Type Speed: 30 km/h

S. Motoo, R. Hirasawa, K. Ota, R. Furuya (Yamanashi Univ., Univ. of Tokyo, Yokohama Nat. Univ.)26 Problems of Pt catalyst Green Hydrogen Research Center, YNU

Problems of cathode catalyst Pt resources 100 kW FCV Resources of Pt →50 g Pt !! High cost and limited ! ! 39000 ton (2006) Instability of Pt cathode Limit of reduction for Pt usage! 800 million

Number of motor vehicles (2009) 965 million (in the world)

27 Concept of Non Pt Cathode for PEFCs Green Hydrogen Research Center, YNU

High stability

High catalytic Combined activity

Group 4 and 5 metal oxides are stable in acid and O2 . Development of innovative materials.

28 Single cell performance

Green Hydrogen Research Center, YNU 2 Zr oxide-based cathode - H2/O2 = 0.2/0.3 MPa-G 1.0 101 Operation condition IR included @ 0.6 V Temp. : 80℃ R. H. : 100 0.9 Membrane : Nafion211 0 H2/O2 = 0.2/0.3 MPa-G 10 / V / 0.8 Loading : 10 mg/cm2 -1

0.7 10 voltage 0.6 10-2 Ti Zr Cell Cell IR corrected 0.5 cm A / V 0.6 density @ Ta 10-3 0.4 2008 2010 2012 2014 2016 0 0.5 1.0 1.5 Current Year Current density / A cm-2

1.2 A cm-2 @ 0.6 V (IR corrected) Cell performance increased drastically. 29 By Toppan Printing Green Hydrogen Research Center, YNU

PEFC for Future Generation

➢ More Stable Fuel Cell

➢ More Efficient Fuel Cell

Operating voltage: ~ 0.9 V Energy Efficiency: ~ 60 %(HHV) Operating temperature : 120 oC or higher Our target: NPGM Catalyst without Carbon. 30 Onset potential of oxide cathode Green Hydrogen Research Center, YNU

0.2 Onset potential=1.15 V 0 TixNbyOz+ Ti O _30oC

-0.2 4 7 High onset potential

1 - -0.4 Zr-CNO / / mA g mA / -0.6

MWCNT_30oC High quality of active point. ORR i -0.8 More than Pt ?

-1.0 TixNbyOz+ o Ti4O7_80 C -1.2 0.6 0.8 1.0 1.2 E vs. RHE / V Fig. Potential-ORR current curves of

TixNbyOz+Ti4O7 and Zr-CNO/MWCNT. 31 Onset Potential during the potential Cycle Green Hydrogen Research Center, YNU

1.2

80 oC

1.1 30 oC

Start-stop cycle test

1.0 / V vs. vs. / RHE V

1.2 onset E 80 oC No change during cycles. 1.1 30 oC Load cycle test Active points are stable. 1.0 0 5000 10000 15000 20000 Cycle /-

Fig. Onset potentials of TixNbxOz supported by Ti4O7. 32 2 Eonset ~ - 20 nA/cm , Ti:Nb = 85:15 Acknowledgment Green Hydrogen Research Center, YNU

The author thanks to the members of NPGM oxide cathode project for their help and the New Energy and Industrial Technology Development Organization (NEDO) of Japan for the financial support.

33 Green Hydrogen Research Center, YNU

Green Hydrogen - Key For the Future Sustainable Growth

Thank you for your kind attention!! 34