Water Electrolysis R&D at ZBT - NRW.INVEST

THE HYDROGEN AND FUEL CELL CENTER

Kamingespräch Japan/NRW

Angelika Heinzel, B. Oberschachtsiek, S. Stypka, A. Gusak

Düsseldorf, August 2020

Water Electrolysis R&D at ZBT

2 © by ZBT – all rights reserved. Confidential – no passing on to third parties

Our core competences

Hydrogen – from generation to application

Hydrogen is a key component in the future energy system. More than

15 years of experience in hydrogen generation by reforming, process

and plant development and safe handling of hydrogen and other fuels

strengthens ZBT in further activities for the implementation of green

hydrogen into the future energy system. Consequently, ZBT has

expanded the hydrogen portfolio addressing the following topics:

- Electrolysis

- Hydrogen Infrastructure and Quality

- Chemical fuels, Hydrogen Carriers

- Hydrogen Generation by Reforming, Cracking


Benchmark of commercial electrolysers

Bild oben links © thyssenkrupp, übrige: ZBT

Hydrogen usage in combined steel an chemical plants

Renewable electricity, green hydrogen, usage of CO/CO2 for synthesis of chemicals

Since 2016

Selection of 3 different commercial systems

Operation- Dynamic operation- Operation strategies- Hydrogen quality- Storage and usage

Installation- Plant integration- Safety- Logistics

4Pictures: ZBT

High Temperature Electrolysis

PEM Electrolysis

Alkaline Electrolysis

H2 Storage 200 bar

Compressor

H2 Storage 1000 bar H2 Storage 500 bar

Compressor & Chiller

Testing Room Dispenser 700 & 350 bar

Fuel Cell CHP Unit (PAFC, Fuji Electric

Hydrogen test field at ZBT


System Comparison of Electrolyzers

Alkaline water electrolysis (AWE)

Manufacturer: McPhyH2-Production: 10 Nm³/hPressure: 10 barNo. of stacks: 2Operation Temperature: 40-50 °C

© ZBT

© ZBT

© McPhy



Polymer electrolyte membrane water electrolysis (PEM)

Manufacturer: ArevaH2-Production: 5 Nm³/hPressure: 35 barNo. of stacks: 1Operation temperature: 60-65 °C

© ZBT© ZBT

© ZBT



High temperature steam electrolysis (Solid oxide electrolysis: SOEC)

Manufacturer: SunfireH2-Production: 5 Nm³/hPressure: atm.No. of stacks: 2 modules with each 3 stacksOperation temperature: 700-860 °C

© ZBT © ZBT

© ZBT


Dynamic operation data

High temperature steam electrolyzer

§ Load change from 100 % to 20 % in 5 min

§ 15 min at 20 % load§ Load change back to 100 % in 5 min

Alkaline water electrolyzer§ 20 load cycles (load change from 100 % to

20 % in 5 min, 5 min at 20 %, load change back to 100 % in 5 min

§ Measurement of polarization curve before and after cycling



AWE PEMWE HTE/SOEC AEMWE

H2 production per stack/module in Nm³/h

5 (115 cells) 5 (21 cells) 2.5 (3 stacks with 30 cells each)

1

Cell temperature / °C 40-50 60-65 700-860 30-70

Cell voltage / V 1.6-2.3 1.6-2.2 1.0-1.6 1.8-2.4

Stack efficiency (@ fullload) / % (in relationto thermoneutral voltage)

~67 ~72 ~109 N/A

Advantages Well established technology, availablefor larger plant sizes, cost, lifetime, non-noble electro-catalysts available

Simpler BoP (gas purity, corrosionresistance), high power densities, high pressure, compactstack design, high purity of gases

High electricalefficiency, integrationof high temperatureheat required, non-noble electro-catalysts available

Simpler BoP (gas purity, corrosion resistance), potential for higher power densities and higher pressure

Disadvantages Low current density, maintenance costs(system is highly corrosive), lower purity of gases (gascrossover)

Expensive stacktechnology, acidic cellenvironment, moresensitive to waterquality, only noble electro-catalysts available

Limited long termstability, not as dynamic as AWE and PEMWE, most expensive technology

Still mostly R&D, only very small plants available, fast membrane degradation


Fundamentals –AEM Water Electrolysis(AEMWE)


AEMWE – Reaction

Images: Enapter, www.enapter.com

2H2

4H2O

Ano

deM

embr

ane

OH-

Cat

hode

O2+2H2O

+ -

Overall Cell Reaction 4H2O→2H2+O2+2H2O

Anode Reaction Oxygen Evolution Reaction (OER)

4OH-→O2+2H2O+4e-

Cathode Reaction Hydrogen Evolution Reaction (HER)

4H2O+4e-→2H2+4OH-


AEMWE – Cell Design & Materials

P. Trinke, et al, Hydrogen Crossover in PEM and AlkalineWater Electrolysis: Mechanisms, Direct Comparison and Mitigation Strategies, Journal of The Electrochemical Society, 165 (7) F502-F513 (2018)

AEMWE Materials

Liquid Electrolyte 1 M K2CO3, KOH

Separator, Diaphragm, Membrane

Quaternary AmmoniaPolysulfone - QAPS (e.g. A201, Aemion, fumasep)

OER catalyst Co3O4

HER catalyst Ni, CeO2-La2O3

Typical currentcollector/PTL

Ni, SS

Cell sealant Synthetic rubber orfluoroelastomer

QAPS

PTL

PTL


AEMWE – Characteristics

Images: Enapter, www.enapter.com

Typical Discharge H2 pressure /bar

<35 bar

Conventional current density / mA cm-2

200-1000

Cell area / cm² <300

Demonstrated durability / h N/A

Hydrogen purity / vol.-% N/A

Typical current efficiency / % N/A

Demonstrated rated productionper stack/module / Nm3 h-1

1

Specific stack energy consumption / kWh Nm-3

4.8-5.2

Specific system energy consumption / kWh Nm-3

N/A

Capital cost / € kWel-1 N/A

Technology status First products available, but mostly R&D


PEM Electrolysis: Stack Testing


Test bench

§ Max. 40 kW electrical power at stack

§ Max. 2.000 A stack current

§ Up to 35 bar pressure H2 and O2

§ DI water feed H2 and O2

§ Integrated Reference 3000 with Reference 30k Booster (EIS)

§ Inline gas analysis

§ O2 in H2 (cathode)

§ H2 in O2 (anode)

§ Fully automated operation

à Broad range of different stack sizes and designs can be characterized


Stacks tested (Giner ELX and H-TEC Systems)

§ Active cell areas from 50 cm² to 450 cm²

§ Stack currents from 60 A to 1130 A

§ H2 production rates from 0.125 Nm³ h-1

to 1.65 Nm³ h-1

© ZBT

© ZBT


Evaluation – improvement during initial 400 hours

The first 16 days Polarization curves

Cell voltage at certain current densityDegradation rate

T = 35 °C

T = 60 °C

0 – 10 µV / h


Accelerated aging by cyclic operationCurrent Design of Experiment: Randomized full factorial design with centerpoint

Temperature / °C

60 70 80

Load

Cha

nge

/A c

m-2

0 Run 1 Run 3

1 Run 5(AST)

1.9 Run 2(AST)

Run 4 (AST)

Testing of 4 identical stacks

Starting with a run-in procedure§ Steady state operation at 1.2 A/cm2 and 60 °C

for 12 daysRun 1 & Run 3:

§ Steady state operation at 1.2 A/cm2 for 5 daysRun 2 & Run 4 (Accelerated Stress Tests)§ Dynamic operation for 5 days with galvanostatic

load changes at 0.1 Hz: lowest load (0.1 A/cm2) à highest load (2 A/cm2) and back again;

Run 5 (AST/ Centerpoint):§ Dynamic operation for 5 days with load changes

from 0.1 A/cm2 to 1.1 A cm2

Analysis: Recording of polarization curves every 24 h


Comparison of first measured and calculateddegradation rates (via Artificial Neural Networks (ANN))

Results / first stack out of four.

ASTDegradation @1.2 A cm-2 /

µV h-1

Degradation model @1.2 A cm-2 /µV h-1

Run 5 (AST/Centerpoint, 70°C)

19,8 11,8

Run 3 (80°C) 19,8 36,5

Run 1 (60°C) 25,9 28,1

Run 2 (AST, 60°C) 23,7 20,8

Run 4 (AST, 80°C) 26,0 12,2


Results: Cell voltages at different current densities

Run-in procedure 60 °C

Run 5 (AST) 70 °C

Run 380 °C

Run 160 °C

Run 2 (AST)60 °C

Run 4 (AST)80 °C

WWW.ZBT.DE

THE HYDROGEN AND FUEL CELL CENTER

Zentrum für BrennstoffzellenTechnik GmbHCarl-Benz-Straße 201 / D-47057 Duisburg

Supported by:

Sebastian Stypka+49 203 7598 – 2188 / [email protected]

Thank you for your attention!

Documents

Water Electrolysis R&D at ZBT - NRW.INVEST