H2NEW: Hydrogen (H2) from Next-generation Electrolyzers of Water Overview

H2NEW: Hydrogen (H2) from Next-generation
Electrolyzers of Water Overview
Director: Bryan Pivovar, National Renewable Energy Laboratory (NREL)
Deputy Director: Richard Boardman, Idaho National Laboratory (INL)

Date: 6/13/2021
 Project ID # P196
DOE Hydrogen Program
 2021 Annual Merit Review and Peer Evaluation Meeting
This presentation does not contain any proprietary, confidential, or otherwise restricted information.

Project Goals

 Goal: H2NEW will address components, materials integration, and manufacturing R&D to enable
 manufacturable electrolyzers that meet required cost, durability, and performance targets,
 simultaneously, in order to enable $2/kg hydrogen.

 H2 production
 Low-Temperature target

Overview

 Timeline and Budget National Lab
 • Start date (launch): October 1, 2020 Consortium Team*
 • FY21 DOE funding: $10M
 • Anticipate minimum $50M over 5 years
 • 75% low temperature electrolysis due to higher TRL
 and intermittency

 Barriers
 • Durability
 • Cost
 • Efficiency
 * H2NEW has started as an exclusive National Lab funded effort but it is anticipated
 to expand to include academic and industrial partners in the near future.
H2NEW: Hydrogen from Next-generation Electrolyzers of Water 3

H2NEW Acknowledgements
 DOE Managers: David Peterson, Ned Stetson, Will Gibbons, Katie Randolph, Eric Miller, James Vickers
 NREL Team Members: Bryan Pivovar, Shaun Alia, Mike Ulsh, Guido Bender, Nick Wunder, James Young, Jason Zack, Scott Mauger, Carlos
 Baez-Cotto, Jason Pfeilsticker, Sunil Khandavalli, Allen Kang, Elliot Padgett, Dave Ginley, Sarah Shulda
 LBNL Team Members: Nemanja Danilovic, Ethan Crumlin, Ahmet Kusoglu, Michael Tucker, Adam Weber, Julie Fornaciari, Claire Arthurs,
 Arthur Dizon, Jiangjin Liu, Grace Anderson
 ANL Team Members: Debbie Myers, Rajesh Ahluwalia, C. Firat Cetinbas, Andrew Star, Xiaohua Wang, Nancy Kariuki, Jaehyung Park
 LANL Team Members: Rangachary Mukundan, Siddharth Komini Babu, Xiaoxiao Qiao
 ORNL Team Members: Dave Cullen, Erin Creel, Haoran Yu, Jefferey Baxter, Shawn Reeves, Michael Zachman, Harry Meyer, Michael Kirka,
 Christopher Ledford
 INL Team Members: Richard Boardman, Dong Ding, Lucun Wang, Jeremy Hartwigsen, Gary Groenewold
 PNNL Team Members: Olga Marina, Jamie Holladay, Chris Coyle, Kerry Meinhardt, Dan Edwards, Matt Olszta, Nathan Canfield, Lorraine
 Seymour, Nathanael Royer, Jie Bao, Brian Koeppel
 LLNL Team Members: Brandon Wood, Joel Berry, Penghao Xiao, Tim Hsu, Namhoon Kim
 NETL Team Members: Greg Hackett
 NIST Affiliate Team Members: Daniel Hussey and David Jacobson.

H2NEW: Hydrogen from Next-generation Electrolyzers of Water 4

Relevance – 2020’s Decade of Hydrogen

 https://www.bloomberg.com/news/articl
 es/2021-03-02/hydrogen-is-jump-ball-
 in-global-clean-energy-race-kerry-says
 https://www.france24.com/en/live-
 news/20210331-the-global-race-to-
 develop-green-hydrogen

 https://hydrogencouncil.com/en/ Now is the time for hydrogen and the “global race” is on

H2NEW: Hydrogen from Next-generation Electrolyzers of Water 5

Relevance – H2NEW connection to H2@Scale

 • Making, storing, moving and
 using H2 more efficiently are
 the main H2@Scale pillars and
 all are needed.
 • Making H2 is the inherently
 obvious, first step to spur the
 wide-ranging benefits of the
 H2@Scale vision.
 • Electrolysis has most
 competitive economics and
 balances increasing renewable
 generation challenges.
 • Timeframe is short, competition
 intense, coordinated effort
 critical for domestic
 Illustrative example, not comprehensive
 https://www.energy.gov/eere/fuelcells/h2-scale competitiveness.
H2NEW: Hydrogen from Next-generation Electrolyzers of Water 6

Relevance/Approach – H2NEW focus

 • A comprehensive, concerted effort focused on overcoming technical barriers to enable,
 affordable, reliable and efficient electrolyzers to achieve

Approach – Consortium Structure and Support Posters

 Director (LTE)
 • Task Based Structure Split between:
 FOA Projects
 Stakeholder H2NEW Co- Bryan Pivovar
 Advisory Director (HTE) Outreach
 Deputy Director (LTE) Deputy Director (LTE)
 • Low Temperature Electrolysis (LTE), 75%:
 Board (SAB) Richard
 Durability and AST Integration and Protocol Data
 Boardman
 Development and Validation
 Validation
 – Task 1 Durability (P196a) Debbie Myers
 Nem Danilovic

 – Task 2 Performance (P196b)
 – Task 3 Scale-up (P196c) Task 1 Liasons for Task 2 Liaisons for LTE
 Performance
 Task 3 Liasons for LTE
 Scale Up
 LTE Durability
 – Task 3c Analysis (P196d) S. Alia, R. Mukundan G. Bender, A. Weber M. Ulsh, D. Wood

 • High Temperature Electrolysis (HTE), 25%:
 – Task 5 Durability (P196e)
 – Task 6 Characterization (P196f)
 – Task 8 Modeling (P196g)

 See associated AMR posters for additional details
 on Approach, Accomplishments, and Future Work

H2NEW: Hydrogen from Next-generation Electrolyzers of Water 8

H2NEW Activities: Low Temperature
Electrolysis (LTE)

Relevance: Hydrogen Levelized Cost (PEM Centric)

 LTE Tasks Structured to address key
 issues of Performance, Cost and
 Durability in order to achieve

Relevance: Stack Costs (PEM Centric)

 Stack Targets Status 2023 2025
 Cell (A/cm2@1.9V) 2.0 2.5 3.0
 Efficiency (%) 66 68 70
 Lifetime (khr) 60 70 80
 Degradation (mV/khr) 3.2 2.75 2.25
 Capital Cost ($/kW) 350 200 100
 PGM loading (mg/cm2) 4 1 0.5

 H2NEW highly focused on decreasing
 stack costs.

 Improved fabrication and thrifting of
 materials will lead to lower costs,
 higher operating currents, and
 scalable manufacturing processes.

 Focus of H2NEW Tasks addresses stack cost reduction based on operating current,
 CCM cost reductions, and manufacturing processes
H2NEW: Hydrogen from Next-generation Electrolyzers of Water 11

Approach: Select LTE Milestones*
 Milestone Name/Description Due Date Type Status
Work with HFTO to establish Stakeholder Advisory Board (SAB) and Accelerated Stress Test Working Group
 12/31/2020 QPM Complete
(ASTWG). – All Labs
Finalize standard, state-of-the-art MEA material set, fabrication process, and/or source to be utilized in baseline
 12/31/2020 QPM Complete
studies including those for durability, performance, and scale-up/integration – All Labs
Identify parameter space and experimental matrix that support the model needs of the consortium with regards to
 3/31/2021 QPM Complete
in-situ, ex-situ, and in-operando experiments. Labs – NREL, LBNL, ANL.
Assess the impact of the stress tests on electrode, membrane, and PTL through voltage loss breakdown and use ex-
situ characterization to identify degradation mechanisms and support AST development. Determine initial stressors
 6/30/2021 QPM On Track
to be investigated in detail for potential to accelerate specific degradation mechanisms. Labs – NREL, LBNL, ANL,
LANL.
Establish and validate single cell performance testing protocols on SOA MEAs with PGM loading of

Approach: Operating Strategy
 Existing Systems Future Systems
 Storage Refill Mode Renewable Following
 System Supplied
 Load Load
 100% 100%

 Off/Idle Off/Idle

 • Steady state operation Time Time
 • Turn system on at certain vessel pressure • Follow renewable energy supply
 • Refill system at 100% system power • Maybe cap high and low performance
 • Switch system to off or idle to minimize degradation
H2NEW: Hydrogen from Next-generation Electrolyzers of Water 13

Approach: State-of-the-Art
 Existing Systems** Future Systems
 • 2V @ 2A/cm2 • 2V @ ≥ 2A/cm2
 • 2-3 mg/cm2 PGM • Thinner membranes
 catalyst loading on • Lower loadings
 anode & cathode • ≥ 80k hours
 • 60k – 80k hours in • Supply following
 commercial units
 • Renewable & Grid
 • Niche applications integrated
 – Life support applications
 – Industrial H2
 – Wind
 – Power plants for
 – Solar
 cooling
 – Nuclear
 • $3.7/kg H2 production*
 • $2/kg H2 production*
*High volume projection: https://www.energy.gov/sites/prod/files/2017/10/f37/fcto-progress-fact-sheet-august-2017.pdf
** K.Ayers, AMR Presentation PD094, 06/2014
 H2NEW: Hydrogen from Next-generation Electrolyzers of Water 14

Approach: LTE Tasks

 • Durability (Task 1, P196a)
 – Establish fundamental degradation
 mechanisms
 – Develop accelerated stress tests
 – Determine cost, performance, durability
 tradeoffs
 – Develop mitigation
 • Performance (Task 2, P196b)
 – Benchmark performance
 – Novel diagnostic development and
 application
 – Cell level models and loss
 characterization
 • Scale-up (Task 3, P196a)
 – Transition to mass manufacturing
 – Correlate processing with performance
 and durability
 – Guide efforts with systems and
 technoeconomic analysis (Task 3c, P196d)

H2NEW: Hydrogen from Next-generation Electrolyzers of Water 15

Low Temperature Electrolysis (LTE)
Task 3c: Analysis (more content in AMR Poster P196d)

Relevance/Approach: Analysis Task Overview
 Performance System cost
 • This task leverages expertise in modeling (ANL) modeling (NREL)
 system cost and performance
 modeling from NREL and ANL to
 benchmark H2NEW cost,
 durability, and performance Experimental
 research
 targets
 • Experimental and analysis
 capabilities form a crucial
 Electrolyzer
 feedback loop for identifying cost,
 barriers and validating progress durability,
 and
 towards H2NEW targets performance
 targets

H2NEW: Hydrogen from Next-generation Electrolyzers of Water 17

Accomplishment: Developing a Reference PEM Electrolysis
 System by Building upon ANL-Developed Design
 Sample Parasitic Loads
 • GCTool model for accurate representation of the system layout, and BOP components and flows
 Mechanical BOP kWh/kg-H 2
 • Model based losses for H2 losses because of H2/O2 crossover, H2 purge (LPHS), and O2 removal Water Pumps 0.10
 (DeO2) Radiator Fan 0.71
 Cooling Tower 0.02
 • Parasitic loads: rectifier/transformer, chiller, TSA dryer (regeneration and blower)
 TSA Dryer System
 DeO2 Electrical Heater 0.14
 Regen Electrical Heater 0.19
 Tail Gas H2 Blower 0.00
 Electrical BOP
 Rectifier/Transformer 3.69
 Hydrogen Loss
 DeH2 0.22
 Crossover H2 and O2 0.43
 Total 5.51

H2NEW: Hydrogen from Next-generation Electrolyzers of Water 18

Accomplishment: Models Contextualize Advances in Cell Components
 and Quantify Remaining Progress Needed To Achieve DOE Targets
 Stack Performance Targets
 70% voltage efficiency 97.5% current efficiency V/I target: 1.79 V at 3 A/cm2, 300 psi, 0.4 mgIr/cm2 anode catalyst loading

 Target ASR and OER Activity
 • OER Activity: Shorting-corrected current density
 Target H2 Crossover at 20oC
 at iR-corrected 1.45 V, 80oC, 1 atm; Reference Example Target Application to PFSA
 • Stack efficiency = Voltage efficiency (70%) x
 value: ~100 A/gIr for 0.4 mgIr/cm2, 60 mV/dec Membrane
 Current efficiency (97.5%)
 Tafel slope • With the status 100 A/gIr OER activity, it is more
 • Reference H2 crossover for N211 in fuel cells:
 • Reference Values of ASR N211 membrane: 20 difficult to meet the current efficiency target
 3 mA/cm2.atm at 100% RH.
 mΩ.cm2 at 100% RH, 80oC, 0.1 S/cm conductivity than V/I target
 • Meeting current efficiency target at 80oC with
 Example contact resistance: 12 mΩ.cm2 • With 2 to 3.5 mil PFSA membranes and 5x
 N212 membrane requires 40% reduction in H2
 • Possible to meet V/I target at 80oC with N212 OER activity, possible to meet both V/I and
 crossover
 membrane and status OER activity current efficiency targets
 80 1.5 4
 97.5% Current

 H2 Crossover at 20°C, mA/cm2.atm
 Efficiency Line

 Membrane Thickness, mil
 70 90°C
 3
 80°C V/I Target Line,
 ASR, mΩ.cm2

 1.0
 60 500 A/gIr OER Activity
 60°C
 2
 V/I Target Line,
 50
 LIr: 0.4
 mg/cm2 100 A/gIr OER Activity
 0.5
 i: 3 A/cm2
 40 1
 E: 1.79 V
 P: 300 psi 97.5% Current Efficiency
 30 0.0 0
 50 100 150 200 250 300 350 400 450 500 60 70 80 90 60 70 80 90
 OER Activity, A/gIr Stack T, °C Stack Temperature, °C

H2NEW: Hydrogen from Next-generation Electrolyzers of Water 19

Accomplishment: Duty cycle implications for ASTs

 LMP
 heatmaps
 can give
 insight into
 potential
 operating
 strategies

 On-off cycle duration and frequency
 can help support AST development.

H2NEW: Hydrogen from Next-generation Electrolyzers of Water 20

Accomplishment: Hydrogen cost impacts

 Location Marginal Pricing (LMP) for Both capital costs and electricity
 electricity can be used to explore prices critical to HLC.
 operating strategies

H2NEW: Hydrogen from Next-generation Electrolyzers of Water 21

Low Temperature Electrolysis (LTE)
Task 1: Durability (more content in AMR Poster P196a)

Approach: Task 1 (Durability)
 Operando cell studies Ex situ component studies Accelerated Stress Tests
 Determine key stressors Membrane a)
 2

  Limits of durability and the impact  Orders of magnitude 1.9

 accelerating degradation acceleration of component 1.8
 of different membrane chemistry

 E [V]
 1.7

 Identify relevant degradation  Variables: Side chain, equivalent degradation rates 1.6

 mechanisms at the component weight, pre-aging, reinforcements,  Assess cost and durability trade- 1.5
 1.4

 recombination layers and/or offs, accelerate materials 0 15 30 45 60
 level Time [s]

 radical scavenging development, MEA integration,
  Impact of seal area/edges, and optimal operating strategies
 for LTEs
 pressure 2025
 Understanding Understanding and Evaluation Solutions 80,000 h
 2.24 µV/h
 Mitigation Strategies 0.5 mgPGM/cm2
 Catalyst
  Develop and implement operational,
 materials, and cell design-based degradation
  Aqueous electrochemical cell coupled with mitigation strategies
 ICP-MS  Coordinate with AST development,
 Quantify losses associated with  Potential and potential profile dependence of technoeconomic analysis, and cell fabrication
 different operating conditions the dissolution of anode catalysts tasks
  Correlation with oxidation state

 In-cell Diagnostics: Ex situ component characterization:
 Voltage loss SEM, TEM, X-ray spectroscopy, scattering, tomography,
 I-V curves, impedance spectroscopy,
 breakdown/modeling microelectrode studies
 cyclic voltammetry, fluoride emission
H2NEW: Hydrogen from Next-generation Electrolyzers of Water S. M. Alia, S. Stariha, R. L. Borup, J. Electrochem. Soc. 2019, 166.; https://www.hydrogen.energy.gov/pdfs/review19/ta022_alia_2019_o.pdf 2019. 23

Approach: Cell Aging Studies
 Component-level Stressors/Variables
 Initial work plan:
Anode Membrane Porous transport layer
 • Operating the rainbow stack and to
Catalyst loading Membrane Corrosion protection
 thickness material
 start studies evaluating lower
 potential limits to separate the
Hydrogen crossover rate Compression Thickness
 impact of sudden potential
Steady-state potential Differential Structure changes from high potential in
 pressure
 catalyst layer degradation.
Voltage sweep rate/profile Pressure cycling Potential exposure
 • Continued upgrading of electrolysis
Voltage limits for cycling Mechanical stress Cycling frequency testing capability and increased
Length of holds at voltage Local dehydration Redox cycling throughput through new test
limits equipment and expanding
Temperature Temperature Temperature capability of current equipment.

 In-cell Diagnostics: Ex situ component characterization:
 Voltage loss
 I-V curves, impedance spectroscopy, SEM, TEM, X-ray spectroscopy, scattering,
 breakdown/modeling
 cyclic voltammetry, fluoride emission tomography, etc.

H2NEW: Hydrogen from Next-generation Electrolyzers of Water 24

Progress: Cell Aging Studies
 Intermittent Operation
 Anode catalyst layer stressors:
 a) 2
• Lower anode catalyst loading, higher
 1.9
 cycling frequency significantly
 increase performance loss due to 1.8

 E [V]
 intermittent operation 1.7

• Sweep rate less critical 1.6

• Simulated crossover reduces near- 1.5

 surface iridium, dramatically increases 1.4
 0 0.5 1 1.5 2 2.5 3
 dissolution and loss i [A cm‒2]

 Hydrogen Crossover

 Catalyst aggregation,
 increased interfacial tearing

H2NEW: Hydrogen from Next-generation Electrolyzers of Water 25

Progress: Cell Aging Studies

 )
 2
 4 2.08 2.2

 Voltage

 Current
 2.06
 3 2

 Conditioning 2.04

 1 day

 Voltage (V), Current Density (A/cm
 Duration

 Voltage at 3 A (V)
 2 1.8

 Voltage (V)
 2.02

 1 1.6
 2 20 mV
 0 1.98 1.4

 Mar 11 Mar 12 Mar 13 Mar 14 Mar 15 Mar 11 Mar 13 Mar 15 0 0.5 1 1.5 2 2.5 3

 2
 Time Test Time Current Density (A/cm )

 Baseline efforts: Conditioning Processes
 10
 -3 1.7 V Hold

• Developing a consistent start point for 15
 Kinetic
 durability testing between users, labs

 ), Voltage (V)
 0.9

 resistance
• Evaluating variations in catalyst layer 0.89
 10 decreases
 formation and membrane preconditioning,

 )
 2 0.88

 2
 5

 cm
 their impact on conditioning time and 0.87

 performance 0 Time = 64.1 min

 -Z'' (
 0.86
 Current Density (A/cm

 Voltage Time = 299.1 min

• Separating losses to evaluate how 0.85
 Current
 -5
 Time = 534.0 min

 Time = 769.0 min

 performance changes occur during 0.84 HFR varies
 conditioning 200 400 600 0.155 0.16 0.165 0.17 0.175 0.18 0.185

 Time (min) Z' ( cm
 2
 )

H2NEW: Hydrogen from Next-generation Electrolyzers of Water 26

Approach: Ex-situ characterization of
MEAs/components/interfaces
• Summary: optical, electron microscopy, and X-ray Technique Facility
 X-ray Absorption Spectroscopy APS, ALS
 characterization techniques to assess changes in: Ultra-small, small, and wide-angle X-ray APS: USAXS, SAXS, WAXS
  Anode morphology, pore size, catalyst scattering ALS: SAXS and WAXS
 aggregate/agglomerate size, ionomer distribution Micro and Nano-X-ray computed
 ALS, APS
 tomography
  Anode catalyst oxidation state, atomic structure, and Micro X-ray computed tomography
 LANL, NREL Benchtop
 migration ALS, APS
 Neutron imaging Tomography NIST
  PTL coating degradation and titanium passivation Focused ion beam and scanning electron
 LANL, ORNL
  Membrane thinning, tearing and pinholes, interfacial microscopy
 Scanning transmission electron
 swelling, and delamination microscopy
 ORNL

  Microelectrode measurements of interface between catalyst Scanning electron microscopy ANL, LANL, ORNL
 and ionomer to study ionomer degradation and effect on X-ray photoelectron spectroscopy ORNL
 water transport Optical microscopy ANL, ORNL

 • First year characterization development efforts: Brunauer–Emmett–Teller ANL, LANL, NREL, ORNL

 Mercury intrusion porosimetry LANL
  Automated image acquisition and analysis methods for
 tracking dissolved metal nanoparticles through the X-ray fluorescence spectroscopy ANL, LANL, NREL
 membrane Ion Chromatography LANL
  Absolute quantification of metal loss from electrodes using Inductively-couple plasma-mass
 ANL, NREL
 the Z-method spectrometry

  Identical location STEM
 H2NEW: Hydrogen from Next-generation Electrolyzers of Water 27

Progress: Ex-situ characterization of
MEAs/components/interfaces
 Identical-Location Scanning Transmission Electron Microscopy Capability Developed and Demonstrated
 Test conditions: Protocol: 30s
 • Catalyst: Alfa Aesar IrO2 provided by NREL 420 cycles 0.5s 2.00 VvsRHE
 • 0.05M H2SO4, Ar-saturated, Room temperature

 1.45 VvsRHE
 30
 s
Area 1: BOL 420 cycles BOL 420 cycles
 Electrochemical
 IrO2 IrO2 performance of cell
 validated
 80
 IrOx_CV_BOL
 60

 40

 Current /µA
 20

 0

 -20

 -40

 -60

 0 0.3 0.6 0.9 1.2

 E vs. RHE /V

 Ar-saturated 0.05M H2SO4,
 50mV/s, 5th cycle.
 EDS analysis: BOL 420 Cycles Preconditioning: 0.05-1.3
 VRHE, 200 mV/s, 40 cycles
 O/Ir atomic ratio 1.2 1.8

H2NEW: Hydrogen from Next-generation Electrolyzers of Water 28

Approach: Accelerated Stress Test Development
 Utilize understanding of degradation mechanisms to develop ASTs for Electrolyzers
 • Develop a duty cycle representative of electrolyzer operation while capturing all degradation mechanisms
  Dynamic load cycling
  Open circuit testing (Load off) going through Ir/IrOx redox
  High current operation (> 3A/cm2)
  High voltage operation (> 2.5V)
  Pressure cycling
  Presence of contaminants (like Fe)

 • Develop component specific ASTs to evaluate the durability of individual components in a reasonable time
 period (1 week to 1 month)
  Define conditions; Set targets based on correlation with duty cycle
  Catalysts : Suitability for dynamic operation. Ability to go through redox.
  Membranes : Durability under dynamic conditions; effect of pressure differentials and contaminants
  PTLs : Resistance to oxidation (Interface resistance and hydrophobicity changes)

H2NEW: Hydrogen from Next-generation Electrolyzers of Water 29

Progress: Accelerated Stress Test Development
 ASTWG Priority list (1=highest priority) • Electrolyzer duty cycle identified as #1 priority
 • Needs to incorporate dynamic load cycling and
Task Name Average Std Dev Ir/IrOx redox cycling
 • Completing baseline materials and testing protocols
Develop Electrolyzer Duty cycle that
captures all relevant stressors at the MEA • Initiating testing matrix for AST development
level 1.375 0.484 • Establish degradation rate at 80 oC: Square wave
Anode Catalyst AST 1.875 0.599 potential from 0V (no load, ambient) to 1.6V (up to
PTL AST 3.9375 0.634 30 bar). 15mins at each potential. Both pressure
Membrane AST 3.125 0.927
 and Redox cycling to capture all degradation modes
Catalyst layer ionomer AST 5.5 1.118
Cathode Catalyst AST 6.375 1.494
 • Monitor pol curves, CVs, and EIS during test and
Bi-polar plate AST 6.1875 1.058 also fluoride emission from both anode and
 cathode
Stressor Name • BOL and EOL particle sizes, membrane thickness,
 membrane mechanical properties, PTL
Dynamic load cycling 2.625 1.932 hydrophobicity and porosity
Shut down/Start up. Allowing Ir/IrOx redox 2.25 1.713
 Future Work:
High current operation (> 3A/cm2) 4.3125 1.919
High voltage operation (> 2.5V) 3.3125 1.434 • Parametric study to quantify influence of individual
Pressure cycling 5.25 1.089 stressors
Presence of contaminants (like Fe) 4.25 1.198 • Working to incorporate other loss mechanisms in
Hydrogen cross-over 5.875 1.615 conjunction with the AST working group
H2NEW: Hydrogen from Next-generation Electrolyzers of Water 30

Low Temperature Electrolysis (LTE)
Task 2: Performance and Benchmarking (more content in
AMR Poster P196b)

Approach: Task 2 Performance and Benchmarking
 NEL 2016 Status • Commercial MEAs Spray coated CCM Status 2020
 2 mg/cm2 total loading are “overdesigned” Circumvent Edisonian • Academic MEAs have
 with high catalyst Approach demonstrated loadings as
 loadings and thick low as 0.05 mg/cm2
 membranes • Translation to high-
 • Poor understanding throughput MEAs is not
 of structure, Commercial materials:
 feasible without an
 interfaces and 0.4 mgIr/cm2 *on 7 mil Nafion understanding of underlying
 performance 2 mil membrane properties and function
N. Danilovic, ECS Transactions, 75 (2016) 395 impacts Ti PTL and Pt coating Z. Taie, ACS AM&I, 12 (2020) 52701
 2025
 Understanding Structure Property Relationships Rational 77% LHV @ 3 A/cm2
 Solutions 0.5 mgPGM/cm2
 Performance & In- Situ Advanced In- Situ Ex-Situ Diagnostics In-Operando Characterization
 Characterization Characterization Cell Level Modeling

 Develop and utilize ex- Develop and utilize Utilize cell level modeling to
Utilize in situ characterization Develop and situ diagnostic techniques operando techniques to understand underlying
techniques to evaluate utilize advanced to extract component identify performance and mechanisms and to guide in
materials and components. electrochemical level parameters and to durability limiting design and optimization of
Establish protocols and diagnostics. determine performance phenomena in operating cells and components
benchmark across institutions.
 impacting characteristics. cells.
H2NEW: Hydrogen from Next-generation Electrolyzers of Water 32

Approach: State-of-Art Performance Diagnostics
• Utilize and establish measurement methods and test procedures • Apply methods to H2NEW
• Develop reproducible analysis pathways for community • Study phenomena at
 Conditioning / Break In HFR free Performance Kinetic Performance interfaces, coatings,
 materials and operating
 conditions
 • Iterate between models and
 experiment
 Voltage Loss Breakdown

 VI-Curves Detailed HFR & Impedance Information

 Add
 EIS

H2NEW: Hydrogen from Next-generation Electrolyzers of Water 33

Approach: Development & Utilization of Advanced Diagnostics
• Enable and conduct the detailed study of phenomena at interfaces,
 coatings, materials and operating conditions Examples:
Segmented Cell Internal Voltage Sensor Cell Hydrogen Crossover Sensing
• High throughput • Separation of losses in-situ • Application of novel Ex-situ &
 • High throughput
• Combinatorial Research • EIS tool to study interfaces In-operando methods degradation studies
 using segmented cell
 or rainbow stack

 • Combinatorial material
 testing

 • Through plane voltage
 distribution and
 potential
 measurements

 • Transport and
 crossover processes

H2NEW: Hydrogen from Next-generation Electrolyzers of Water 34

Approach: Development & Utilization of Ex-Situ Diagnostics
• Enable and conduct the detailed study of material properties and degradation phenomena
• Characterize interfaces, material composition and morphology
 Examples:
Ionic/electronic conductivity SEM, TEM, FIB-SEM & Nano-CT for PTLs • Structure impact on
 conductivity and transport
 • Coating defects & oxide
 thickness
 • Coating penetration
 • Pore structure & pore size
 distribution
 • Nanoscale morphology

 FIB-SEM & Tomography for Catalyst Layers
Corrosion & Passivation • Inform and exchange info
 Before Afte between capabilities and
 r
 with all tasks
 • Support holistic
 understanding
H2NEW: Hydrogen from Next-generation Electrolyzers of Water 35

Approach: Development & Utilization of Advanced Characterization
Techniques
• Operando study of reaction, transport and flow phenomena in cell & at interfaces
• Characterization of impact of material choice, composition and morphology
 Examples:
In situ Micro-XCT Cell Operando characterization
 X-ray Scattering Neutron Imaging Tomography
 Ti felt PTL
 • Water & oxygen
 transport through cell
 components and their
 impacts on
 performance
 • Real time water
In situ X-ray Spectroscopy Cells Advanced High-Resolution Microscopy dynamics &
 degradation
 phenomena

 Fresh AST
 • Hydrophobicity loss
 tracked locally
 • Catalyst-ionomer
 interaction across
 Catalyst-ionomer structures and distribution length scales
H2NEW: Hydrogen from Next-generation Electrolyzers of Water 36

Approach: Multi-physics electrolyzer model

 2-D Cell Level Multiphysics Models

• Provide relevant • Use operando
 parametric studies to obtain
 component level phenomenological
 properties data to guide the
 modeling analysis

• Validate models
 by generating
 physical • Cell diagnostics to
 phenomena at the validate predictive
 component level, cell optimization and
 diffusivity shown mitigation strategies

 H2NEW: Hydrogen from Next-generation Electrolyzers of Water 37

Accomplishment – Operando Diagnostics

 • Q2 QPM: Complete cell design and
 validation of a neutron imaging cell
 to be used with the high-resolution
 imaging detector at NIST. Cell
 performance in imaging hardware
 within ±10% of performance in a
 25 cm2 cell

 ⇒ Performance validated to be within
 10%
 ⇒ Some HFR differences seen due to
 differences in balance of cell
 components

H2NEW: Hydrogen from Next-generation Electrolyzers of Water 38

Accomplishment – Baseline Materials Selection

• Evaluation of Anode PTL materials 2.2
 High loaded MEA (previous work) Low loaded MEA (H2NEW)

 underway with Uncoated
 Ir coated
 420 2.4
 Uncoated EdgeTech PTL
 Uncoated Mott PTL

 – “state-of-the-art” MEAs 2.0 Ir coated EdgeTech PTL
 Performance Pt coated Mott PTL
 360 2.2
 HFR-free
 – “Future Generation” MEAs

 HFR [mΩ cm2]
 1.8 HFR

 Voltage [V]
 Voltage [V]
 2.0
 (FuGeMEA)
 300
 1.6

• Two distinct PTL architectures 240 1.8
 1.4
 – Felt material 180 1.6

 1.2
 – Sintered material 120 1.4
 0.5 1.0 1.5 2.0 2.5 3.0 0.0 0.5 1.0 1.5 2.0 2.5 3.0
• Various PTL parameters -2
 Current Density [A cm ] Current Density [A cm-2]

 – Coating/uncoated • Interplay between MEA loading and PTL confirmed
 • In-house • MEAs with low loadings have higher sensitivity towards
 • At supplier functionality of PTL / catalyst layer interface
 – Thickness • Coatings significantly improve cell resistance
 – Porosity – Improvement of interfacial resistance
 – Improvement of thermal conduction within cell
 H2NEW: Hydrogen from Next-generation Electrolyzers of Water 39

Low Temperature Electrolysis (LTE)
Task 3: Manufacturing, Scale-up and Integration (more
content in AMR Poster P196c)

Approach: Manufacturing Scale Up
 Spray Coating Slot Die Coating R2R Coating
 • Dilute ink • Viscous ink • Viscous Ink
 • Homogenous Ir • Heterogenous Ir distribution • Very high throughput
 distribution • Serves as a model • Translate subscale
 • Low high throughput deposition learnings
 throughput technique
 Understanding and Evaluation 2025
 Understanding/Legacy Model/Scalable Fabrication Engineered @Scale/H2NEW 100 $/kW
 Ink Composition Ink Mixing Electrode Structure/Function Solutions Substrates

Study the impact of ink Study the impact of Impact of substrate type and
composition, solids mixing on the ink deposition method on
content, I/C ratio and stability and structure and function of the
solvent types agglomeration Impact of ink, deposition resulting catalyst layers.
 Ink Rheology technique on the catalyst layer Downselect based on
 structure, ionomer distribution, technoeconomic and
 Study the relationships
 catalyst distribution, manufacturing
 between ink
 agglomerate size on considerations.
 composition, rheology
 and the of ink performance and durability.
 rheology on
H2NEW: Hydrogen from Next-generation Electrolyzers of Water 41

Approach: Integration and Components
 Porous Transport Layer Interfacial Layers • Evaluate the impact Scalable and Engineered
 of additive/ Structures
 • Evaluate
 microporous layers • Design scalable PTL
 commercially
 on the properties structures with
 available PTLs
 and function of tailored porosity,
 • Mechanical and
 PTLs tailored interface and
 transport properties
 Bekaert Mott • Evaluate the PTL wetting properties
 Commercial Commercial • Performance and
 interface topology
 Ti fiber Ti particle durability T. Schuler et al, Adv. Energy Mat.,
 Understanding and
 10 (2020), 1903216
 Evaluation
 on function of PTL 2025
 Understanding/Commercial Model/Interfaces Solutions
 Engineered 100 $/kW
 Mechanical Properties Coatings Interface Structures
 Two Phase Transport Fabrication

 Leonard et al. Solar Fuels
 C. Liu et al, Adv Energy (10.1039/c9se00364a) P. Satjaritanun et al., iScience, 23,
 Mat., 11 (2021), 2002926 (2020) 101783.
 Study PTL mechanical Study impact and Study the coherence of and
 properties. Study the transport through the Study the transport of Use 3D printing and
 type of corrosion
 PTL/membrane PTL/membrane interface water and oxygen tape casting to make
 resistant coatings.
 interfacial mechanical and impact on performance through the PTL. PTLs with tailored
 Investigate non-PGM
 properties. alternatives defects. and durability. characteristics.
H2NEW: Hydrogen from Next-generation Electrolyzers of Water 42

Accomplishment: Titanium PTL/MPL Additive Manufacturing

• Layer-by-layer electron beam melting process performed at E-Beam Fusing of Metal Particles
 ORNL’s Manufacturing Demonstration Facility (MDF)
 – Metal particles melted by e-beam to form a 3D porous structure
 – Adjusting the e-beam focus and movement pattern allows the
 amount of void space (porosity) to be tuned.
Tomography of fabricated PTL
 • 55 mm x 55 mm x 1 mm proof of concept structures
 manufactured from Ti64 with 25% porosity in the highlighted
 center region of interest measured by micro CT
 – Ti64 behaves similarly to pure Ti in manufacturing, but the Al and V
 impurities make it unsuitable for use in a PTL.

 • Next steps: determine upper porosity limit and attempt to
 make porosity-graded PTLs using grade 2 (commercially
 pure) Ti
H2NEW: Hydrogen from Next-generation Electrolyzers of Water 43

Accomplishment: Ti PTL Structure Function Characterization
• 20um Fiber diameter Bekeart PTLs, varying thickness
 at 56% porosity and varying porosity at
 fixed thickness
• N117, Fixed catalyst loading of 0.06 mgIr/cm2
 *Iryna Zenyuk at UCI
• Too porous is bad because the interface suffers
 • ~50% dense is optimal

• Too thick and too thin is bad as well
 (maybe mechanical),
 • 150 um optimal

 • To inform future PTL
 design

 Fixed Thickness Fixed Porosity
H2NEW: Hydrogen from Next-generation Electrolyzers of Water 44

Responses to Previous Year Reviewers’ Comments

 • Not Applicable, first year of project

H2NEW: Hydrogen from Next-generation Electrolyzers of Water 45

Collaborations and Coordination (LTE)

 Leverage across other Consortium: LTE Strategic Advisory Board Members
 HydroGEN 2.0 (HFTO)
 R2R (AMO)
 Million Mile Fuel Cell Truck (HFTO)
 ElectroCAT (HFTO)

 Kathy Ayers Cortney Chris Thomas Jack Mark
 VP R&D Mittelsteadt Senior Brouwer Mathias
 Nel Hydrogen VP Electrolyzer Technical Professor Consultant
 Technology Supervisor
 U.C. Irvine retired (GM)
 Plug Power 3M

 Numerous industrial, academia, and international interactions: Select group of advisors representing OEMs, tier 1
 (IEA, ASTWG, materials suppliers, informal collaborations) suppliers, analysis and manufacturing interests.

 External Facing Website Being Established: h2new.energy.gov

 Initial effort piloted by National Labs (see Slide 4 for full list of project participants by institution), have widely coordinated with other
 research institutions and industry, expect academia and industry to engage further through FOAs and collaborative research.

H2NEW: Hydrogen from Next-generation Electrolyzers of Water 46

Remaining Challenges/Proposed Future Work (LTE)
 (Refer to P149a,b,c & d for more detail at Task Level)
 Task 1 (Durability): Aging Studies; Mitigation Strategies; Ex-situ Characterization of
 MEAs/components/interfaces; Ex-situ Catalyst Durability; Ex-situ Membrane Durability;
 Accelerated Stress Test Development
 Task 2 (Performance): Performance benchmarking, baselining, validation; Cell performance
 testing in support of electrode development; Ex-situ studies focused on performance factors;
 Cell level model development
 Task 3 (Scale-up): MEA fabrication, Interface engineering (inks, electrodes, cell integration and
 interfaces); Components (porous transport layers, recombination layers)
 Task 3c (Analysis): Performance, manufacturing, and system models; Durability factors; Energy
 system integration

 Any proposed future work is subject to change based on funding levels

H2NEW: Hydrogen from Next-generation Electrolyzers of Water 47

Summary: H2NEW LTE
 Degradation and Accelerated Stress Test (ASTs)
 Probing of single stressor demo established for
 degradation pathways correlating with AST
 Rainbow stack for durability AST Working Group Established
 Operando cell and ex situ Mitigation Strategies
 component studies To be informed by degradation and AST
Operando neutron diffraction Identical location microscopy
 cell commissioned and on-line ICMPS
 Understanding
Discretionary funding Understanding
 demonstrated for studying and Evaluation
 allocated to operando degradation Stack Targets Status 2023 2025
 tomography Cell (A/cm @1.9V)
 2 2.0 2.5 3.0
 Task 2: Performance: Structure-Property Relations to Optimized Performance Efficiency (%) 66 68 70
 Lifetime (khr) 60 70 80
Baseline MEA Cell Modeling Degradation (mV/khr) 3.2 2.75 2.25
 Identified parameter space and experimental
Crosstask team Capital Cost ($/kW) 350 200 100
 matrix that support the model needs of the
 established PGM loading (mg/cm2) 4 1 0.5
 consortium with regards to in-situ, ex-situ, and in-
 common MEA, TEA, Systems Analysis
 operando experiments
 testing and prep Performance, manufacturing, and
Identified and system analysis is underway and tools
 sourced PTL Inks, are being developed and implemented
 catalyst layers, porous transport layers Identified Operating Strategy that
 Study of PTL structure property demonstrated Minimizes Cost for Several Electrolyzer
 relations initiated Concentrated ink baselining Costs Identified and sourced PTL
 Identified and sourced PTL between 3 labs Initial Input to Stack Performance
 Feasibility of PTL fabrication via Targets
 3-D printing and tape casting Cell to system level performance model
 H2NEW: Hydrogen from Next-generation Electrolyzers of Water 48

H2NEW Activities: High Temperature
Electrolysis (HTE)
Richard Boardman, H2NEW Deputy Director, and HTE Lead

Relevance/Impact

• H2NEW-HTE will address HTE cell and stack components performance and
 durability to understand degradations and enable manufacturable
 electrolyzers that meet required cost, durability, and performance targets,
 to enable $2/kg hydrogen.
• H2NEW focuses on durability and lifetime of SOEC cells and stacks
• H2NEW is a tightly focused, highly coordinated investigation
 harnessing extensive experimental testing,
 multiscale modeling and detailed materials characterization
 DOE HTE Targets
 – National labs are ideal for this critical work –
 in aggregate, combination of world-class
 experimental, analytical, and modeling tools,
 with the ability to freely share research findings.
 – The array of capabilities needed to understand and
 mitigate degradation does not exist at a single laboratory

H2NEW: Hydrogen from Next-generation Electrolyzers of Water 50

Relevance: HTE Motivation, Barriers, and Opportunity
 HTE – an exceptionally attractive technology for H2 production
 a. O2- -conducting SOECs have evolved to a reasonable state of maturity -- high performance in H2 production efficiency,
 steam utilization, electrical efficiency & utilizing heat to offset demands for electricity. Metal-supported o-SOECs have
 potential for improved mechanical stability.
 b. Operating characteristics that are highly compatible with power plant integration
 c. HTE has the potential to achieve DOE’s cost target for H2 of < $2/kg
 Barriers
 a. High performance is inversely correlated with durability.
 1) Degradation occurs at both anode and cathode interfaces, exacerbated by operation at high production conditions.
 2) Degradation phenomena are well known. Mechanisms are not.
 3) Ability to rationalize, predict and control is immature.
 b. o-SOEC durability plays a major role in the overall cost of hydrogen production -- Cell degradation limits lifetimes
 c. Capital Cost is estimated to be higher than desired
 d. Stack Costs are an important contributor to the overall economics of H2 production
 Opportunity
 If degradation mechanisms were well understood, composition and architecture could be optimized, and operation tuned to
 achieve extended lifetimes, overcoming a key barrier to realizing cost targets

H2NEW: Hydrogen from Next-generation Electrolyzers of Water 51

Relevance: H2NEW HTE Performance Targets
• Performance and Durability 2021 NOAK Plant: Electricity Cost- $30/MWhe
 are the primary factors to Stacks~ $155/kWe; BOP~ $550/kWe
 reducing levelized cost of
 hydrogen (LCH)
 Performance
• Increase life from 30,000 to & Durability
 80,000
• Increase conversion O2 Sales
 efficiency:
 – Reduce gas purification and
 H2 recycle costs (i.e. BOP)
 – improve thermodynamic
 efficiency using high
 temperature process heat
• Optimize stack design
• Co-produce oxygen
H2NEW: Hydrogen from Next-generation Electrolyzers of Water 52

Approach: Select HTE Milestones*
 Milestone Name/Description Due Date Type Status
Develop revised 5-year stack performance, durability and cost stack-level HTE targets to be achieved by H2NEW 12/31/2020 QPM Complete
Identify standard cell compositions for baseline performance and durability testing. Identify supply chain. 12/31/2020 QPM Complete
Test protocol development – standard operating conditions, stressors, initial test matrix for AST 03/31/2021 QPM Complete
Dynamic cycling protocol specification 06/30/2021 QPM On Track
Complete button cell testing under standard operating conditions 6/30/2021 QPM On Track
Demonstrate that two stressors cause reproducible and accelerated degradation in button cells 9/30/2021 M On Track
Complete initial dynamic cycling testing, achieve repeatability and degradation under AST conditions 9/30/2021 M On Track
Demonstrate capability for 3D / enhanced 2D resolution of microstructure of HTE cell 12/31/2021 QPM On Track
Develop concepts for improved (10%) cell performance at 1.28 V 3/31/2022 M On track
Develop in operando test stand for button cells and planar cells 3/31/2022 QPM On Track
Decision: Development & validation of ASTs for HTE-SOECs – 3 component-level ASTs and measure performance
losses. Criteria: Verify that at least one AST captures and accelerates degradation occurring over long time 3/31/2022 Go/No-Go On Track
frames via spectroscopic, microscopic and electrochemical performance measures. Performers: All labs.

 *For complete list, see associated AMR posters for additional details
H2NEW: Hydrogen from Next-generation Electrolyzers of Water 53

Approach: H2NEW HTE Program Flow

 Understanding Rational Solutions

H2NEW: Hydrogen from Next-generation Electrolyzers of Water 54

High Temperature Electrolysis (HTE)
Task 5: Durability Testing and AST Development
(more content in AMR Poster P196E)

Approach: Experimental Investigation to AST

 • Define cell materials, architectures, configurations, and sizes
 • Identify button cell vendor/supplier
 – button cells
 – planar cells
 • Define standard operating conditions: temperature, gas compositions, current/voltage
 • Test button cells under standard operations
 • Determine degradation mechanisms
 • Identify stressors for Accelerated Stress Testing (AST)
 – Develop protocols: matrix with incrementally aggressive conditions
 – Round robin replicates to ensure confidence
 • Determine AST degradation, compare to standard operating conditions
 • Graduate to planar cells
 – standard operations
 – AST matrix

H2NEW: Hydrogen from Next-generation Electrolyzers of Water 56

Technical Accomplishments: Standard Cells Identified

 • Composition identified:
 Ni-YSZ | YSZ | GDC | LSCF-SDC
 – Button cells initially, smaller cell area
 active area is 2-4 cm2 active area is 10-25
 – Graduate to planar cells, larger cell area, 10-25 cm2, cm2
 for direct comparison to button cells
 • PNNL fabrication:
 – explicitly known compositions
 – high quality control
 – adjustable production size, with invariant
 composition and architecture
 – high volume, supplying INL,
 LBNL, & NREL

H2NEW: Hydrogen from Next-generation Electrolyzers of Water 57

Technical Accomplishments: Electrochemical Testing

 • Significant suite of test stands
 assembled
 – > 15 PNNL
 – 11 INL by 06/21
 – 2 LBNL
 • Screening commercial, • 750 - 800oC
 PNNL-fabricated, cells • H2/H2O = 50/50
 • 1.3 v
 • Results • 600 – 2,800 h

 – Commercial cells display poor
 performance reproducibility
 – PNNL-fabricated cells performed
 with greatly improved I-V
 precision

H2NEW: Hydrogen from Next-generation Electrolyzers of Water 58

Technical Accomplishments:
 Post-Test Characterization Commercial Cells
 • Sr migration through the ceria barrier layer, reaction with YSZ to form SrZrO3
 • LSM delamination observed in all cells tested
 • Ni/YSZ did not exhibit any significant changes
 Oxygen Electrode Hydrogen Electrode Cell-related degradation mechanisms
 previously reported:
 GDC YSZ – Hydrogen Electrode
 • Coarsening
 Ni/YSZ • Migration
 • Si poisoning
 – Oxygen Electrode
 • SrZrO3
 • Delamination
 • Cr, S poisoning
 SEM images
 EDS compositions

H2NEW: Hydrogen from Next-generation Electrolyzers of Water 59

Technical Accomplishments: Dynamic Cycling
R&D SOEC testing typically at fixed conditions (V, I, T, P), but, anticipated operation is highly dynamic
 Metal-supported SOEC, air/50% humidified
 C. Graves, J.V.T. Høgh, K. Agersted, X. Sun, M. hydrogen
 Chen et al., July 2014, Department of Energy F. Shen, R. Wang, M.C. Tucker, Journal of
 Conversion & Storage, Technical University of Power Sources, 474 (2020) 228618
 Denmark 700°C
 50% steam
 0.33 A/cm2

 Literature:
 – Cycling power (P, V, or I) does not cause degradation; cycling outside normal range is not studied
 – Steam content cycling is not well studied, but is relevant to intermittent or variable operation
 – Small variations in P, T, Ni reduction/oxidation not expected to impact degradation; large variations
 cause catastrophic failure and so are not useful for AST
 Ongoing:
 – Variables chosen for initial cycling in FY21: steam content, and power
 – Test standard cells under dynamic conditions
 – Assess viability as an Accelerated Stress Test

H2NEW: Hydrogen from Next-generation Electrolyzers of Water 60

High Temperature Electrolysis (HTE)
Task 7: Advanced Characterization
(more content in AMR Poster P196F)

Approach – Multi-Lab, Multi-Capability to Identify Composition,
 Microscale Morphology Changes
 Objectives
 • Identify HTE Cell Degradation & Failure Mechanisms
 • Void formation / cation migration / new phase formation /
 Ni coarsening / Zr redox
 • Discern order of failures – relative kinetics
 Approach
 • Engage materials analysis horsepower
 • conventional analysis at NREL, ANL, PNNL, LBNL
 • accelerator-driven analysis at SLAC, ANL
 remarkable level
 (including in situ, in operando experiments)
 of layer, phase
 • Transmission X-ray Microscopy (TXM) differentiation is
 • X-ray Absorption Spectroscopy (XAS) achievable
 • X-ray Diffraction (XRD)
 • Scanning electron microscopy /
 Energy dispersive X-ray spectroscopy (SEM/EDS)
H2NEW: Hydrogen from Next-generation Electrolyzers of Water 62

Technical Accomplishments
 – Cation Migration by TXM, XAS
 3D Tomography (TXM) of HTE cell cycled 2D XAS map at the Fe edge (top)
 300 H XAS spectra (bottom) Multi-Lab Attack
 INL synthesized and cycled HTE cells
 SNL fibbed sample to size
 NREL coordinated measurements w/ SLAC,
 conducted data analysis and interpretation

 Composition, Microstructure
 Alterations Unveiled
 • Void formation in GDC
 Fe migration
 into GDC
 seem in TXM
 • Iron oxide migration into
 5 μm GDC layer seen in
 2D XAS imaging
 • Potential correlation,
 possible causation wrt
 degradation

H2NEW: Hydrogen from Next-generation Electrolyzers of Water 63

Technical Accomplishments
 – Formation of Gd/Fe-bearing phases
 Magnified XRD of 0 hrs Cell
 XRD Pattern
 Silver Negligible

 Intensity (Arb. Units)
 Nickel
 LCSF secondary phases
 YSZ
 GDC
 Fe2O3
 in benchmark
 experiment

Synchrotron XRD 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

• Total X-ray penetration 2 (at =0.7293Å)
 Magnified XRD of 300hrs Cell
 of cell, integrated
 XRD Pattern
 analysis of all layers Silver
 Pronounced Gd

 Intensity (Arb. Units)
 Nickel
 LCSF
 YSZ
 ferrite formation,
XRD Results – cell cycled 300 hours GDC
 Fe2O3
 after modest
• GdxFeyOz formation (in blue) GdxFeyOz operation time
• Potential correlation, possible causation
 with respect to degradation
 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
 2 (at =0.7293Å)
H2NEW: Hydrogen from Next-generation Electrolyzers of Water 64

High Temperature Electrolysis (HTE)
Task 8: Multiscale Modeling
(more content in AMR Poster P196G)

Approach – Multiscale Modeling

 Objectives
 1. Correlate operating conditions with degradation mechanisms
 2. Develop tools for predicting durability and lifetime over long timeframes
 3. Guide selection of accelerated stress testing (AST) conditions and
 protocols to achieve representative of long-term degradation under
 normal operating conditions
 Approach
 1. Leverage advanced simulation capabilities and codes developed through
 HydroGEN and complementary DOE-funded activities at partner labs
 2. Model validation via close coordination with experiment
 3. High performance SOC modeling groups

H2NEW: Hydrogen from Next-generation Electrolyzers of Water 66

Approach – Atomistics & Computational Thermodynamics
 Atomistics - Ab initio Computational Thermodynamics (CALPHAD)
 Unit cell compositions – e.g. YSZ, Interface Mapping phase stability as a f(composition)
 & phase energies, atom transport, reaction Correlate operating conditions,
 pathways & kinetics, electronic structure e.g. [p(O2)] ∝ current density

YSZ
(Y2O3-
doped ZrO2) Micro-
 structure
 Red – O
Light green – Zr
Dark green – Y

 Computational spectroscopy – quantitative
 link from theory to experiment

H2NEW: Hydrogen from Next-generation Electrolyzers of Water 67

Approach – Phase Field and Multiphysics Modeling
 Phase-field modeling Multiphysics Modeling
 Generating 3D microstructure
 Predict electrochemical performance vs
 Predict degradation phenomena, viz.,
 microstructure, electromigration & diffusion
 coarsening & migration, phase
 (e-, e+, O2-), O2 partial pressures
 transformations, micro-fracture
 3 Elements 3 Material Phases + Pore Degradation-Prone Microstructure Hotspots
 0.46
 Ni A: NiZr solid solution
 Zr B: Ni5Zr intermetallic Phase-field
 O C: ZrO2 (YSZ) simulation
 conditions
 D: Pore
 0
 
 Ni-Zr Uniquely
 Current
 microstructure
 Density
 ZrO2 dependent
 Fracture
 Quantitatively understand degradation mechanisms and controlling factors
H2NEW: Hydrogen from Next-generation Electrolyzers of Water 68

Technical Accomplishments – Ni/YSZ Breakdown
 Driven by
 • Key Degradation: Ni/YSZ fuel electrode breakdown near the electrolyte Current Density

 Electrode Current density ≳ 0.6 A/cm2 NiFCC + ZrO2

 log10[ p(O2) ] (bar)
 Thermodynamic instability
 Ni Degraded Structural changes

 NiFCC
 zone NiFCC + Ni5Zr
 YSZ
 ↑ ohmic resistance
 Electrolyte Interfacial separation
 Failure
 Zr/(Ni+Zr)
 p(O2) for ceramic phase reduction Improved
 Equilibriu NiFCC + ZrO2
 YSZ m p(O2)
 thermo-
 dynamic

 log10[ p(O2) ] (bar)
 (Y2O3- [bar]
 doped ZrO2) accuracy
 Old ZrO2 ZrNi5 + O2  ZrO2 + 5Ni 5.0E-32

 NiFCC
 NiFCC + Ni5Zr
 Oxidation
 Red – O Our ZrO2 ZrNi5 + O2  ZrO2 + 5Ni 5.05E-31
 equilibria
Light green – Zr
 Our YSZ
 (4/31)YNi5 + (28/31)ZrNi5 + O2 
 4.17E-31 shifted 10x
Dark green – Y (2/31)Y2Zr14O31 + (160/31)Ni higher Zr/(Ni+Zr)

 H2NEW: Hydrogen from Next-generation Electrolyzers of Water 69

High Temperature Electrolysis (HTE)
Summary and Conclusions

Collaboration and Coordination
 Task 5. Cell fabrication, operation, AST development PNNL, INL, LBNL
 • A highly coordinated,
 Task 6. Task integration and protocol validation SAB, INL
 interactive four-prong
 Task 7. Advanced characterization NREL, ANL, interfacing SLAC
 strategy – leveraging
 Task 8. Multiscale modeling LLNL, NETL, PNNL
 • leading expertise,
 Integration of Stacks and Balance of Plant Development and Verification
 capability at the National Labs
 • Stakeholder Advisory Board
 • Scott Swartz, Nexceris Integrated Stacks & Pilot Plant
 • Greg Tao, Chemtronergy Balance of Plant Demonstration
 50-250 kWe Stack Assembly
 • John Pietras, St. Gobain Performance Testing
 • Peter Voorhees, Northwestern Stack
 Manufacturing
 • Scott Barnett, Northwestern Short Stack Testing
 • Xiao-Dong Zhou, University of 3-10 cells
 Louisiana-Lafayette
 • H2NEW HTE integration into H2NEW Composite Cells
 the research, development, Accelerated Stress Testing
 demonstration & deployment Materials Development
 HydroGEN
 horizon
H2NEW: Hydrogen from Next-generation Electrolyzers of Water 71

Remaining Challenges and Barriers (HTE)
 (Refer to P196e,f & g for more detail at Task Level)
 Task 5: Durability Testing and AST Development
 i. AST development is a significant intellectual challenge – National Lab-worthy
 ii. Reconfiguring test stand capability with capacity commensurate with program needs is
 a near term challenge
 Task 6: Task Integration and Protocol Validation
 i. H2NEW will generate enormous volumes of data, that will present organization,
 validation, archival and communication challenges
 Task 7: Advanced Characterization
 i. Implementing HTE experiments operating at beam line user stations is not simple
 Task 8: Multiscale Modeling
 i. Degradation processes at the YSZ|GDC|LSCF-SDC interface are probably coupled in a
 non-linear fashion. Defining and modeling the mechanisms will be significantly more
 difficult than the Ni-YSZ|YSZ interface. A National Lab-worthy problem.

H2NEW: Hydrogen from Next-generation Electrolyzers of Water 72

Proposed Future Work (HTE)
 (Refer to P196e,f & g for more detail at Task Level)
 Task 5: Durability Testing and AST Development
 i. Develop AST protocols that accelerate degradation, with fidelity to mechanisms
 functioning at standard operating conditions
 ii. Mature & deploy augmented testing capability sufficient to cover the parameter matrix
 and requisite
 Task 6: Task Integration and Protocol Validation
 i. Organize significant data volume, surmount archival, curation challenges
 ii. Ensure refined protocols are validated, widely available
 Task 7: Advanced Characterization
 i. Refine and implement in situ / in operando analyses at APS, SLAC
 ii. Coordinate interface between testing, modeling and characterization
 Task 8: Multiscale Modeling
 i. Initiate research on degradation at the YSZ|GDC|LSCF-SDC interface
 Any proposed future work is subject to change based on funding levels

H2NEW: Hydrogen from Next-generation Electrolyzers of Water 73

Summary H2NEW HTE

• H2NEW HTE is an ambitious program focused on overcoming barriers to cell and stack durability
 that are impediments to economic competitiveness and industrial implementation
• Materials and component degradation mechanisms are the result of multiple, coupled phenomena
 derived from operating conditions
 – a comprehensive and accurate understanding of the interplay of these phenomena does not currently exist
 – therefore rationalizing, predicting and controlling degradation currently beyond our grasp
• The H2NEW HTE hypothesis is that a systematic, coordinated research program targeting the
 coupled degradation phenomena will yield refinements to composition, fabrication and operation
 that will enable HTE technology to overcome current durability barriers
• Harnessing capability at consortium labs is well underway, initial operational experiments initiated

H2NEW: Hydrogen from Next-generation Electrolyzers of Water 74

Technical Backup and Additional
Information Slides

Advantages of SOEC
  Thermal-Electric process  Either O= or H+ conduction possible
  Pure O2 co-product possible  CO2 electrolysis/ co-electrolysis possible
 70.0 70.0
 Minimum energy for water splitting
 39.7 kWh/kg-H2 (Higher Heating Value) Proven
 Alkaline
 60.0 Energy produced by hydrogen combustion (AE 20 bar)
 60.0
 33.3 kWh/kg-H2 (Lower Heating Value) Proven
 Proton Exchange
 Membrane
 50.0 50.0
 Total Energy (kWh/kg-H2)

 H2 Compression (PEM, 20 bar)

 Total Energy (kWh/kg-H2)
 Power (20 bar) Goal
 Proven Goal
 Thermal
 40.0 40.0
 Thermal

 Proven
 Goal
 Steam generation
 and superheating
 30.0 30.0
 Direct heat

 Proven
 Input to cell

 Goal
 Electricity
 Solid Oxide Electrolysis Cell 20.0
 20.0
 Electricity (SOEC, 20 bar)
 Proven
 Goal

 10.0 10.0

 0.0 0.0
 0.90 1.00 1.10 1.20 1.30 1.40 1.50 1.60 1.70 1.80 1.90 2.00

H2NEW: Hydrogen from Next-generation Electrolyzers of Water
 Operating Voltage 76