3M High Performance, Durable, Low Cost MEAs. 2014 DOE Hydrogen, Fuel Cells, Vehicles Program AMR, June 16-20
High Performance, Durable, Low Cost Membrane Electrode Assemblies for
Transportation Applications
Andrew Steinbach 3M Company
June 18th, 2014
Project ID: FC104
This presentation does not contain any proprietary, confidential, or otherwise restricted information
2014 Annual Merit Review DOE Hydrogen and Fuel Cells and
Vehicle Technologies Programs
3M High Performance, Durable, Low Cost MEAs. 2014 DOE Hydrogen, Fuel Cells, Vehicles Program AMR, June 16-20
Project Overview Timeline
• Project start: 9/1/12 • Project end: 8/30/14
Barriers A. MEA Durability B. Stack Material & Mfg Cost C. MEA Performance
DOE Technical Targets Electrocatalyst (2017)
• Mass Activity: 0.44A/mg • Inv. Spec. Power: 0.125g/kW(rated) • PGM Total Loading: 0.125mg/cm2 • Electrocatalyst, Support Durability:
< 40% Activity, ECSA Loss MEA (2017)
• Q/∆T: 1.45 kW/ºC • Cost: $9 / kW • Durability w/cycling: 5000 hrs • Performance @ 0.8V: 0.300 A/cm2 • Perf. @ Rated Power: 1 W/cm2
Budget • Total DOE Project Value: $4.606MM* • Total Funding Spent: $2.556MM*
• Cost Share Percentage: 20% * Includes DOE, contractor cost-share, and FFRDC funds, as of 3/31/14.
Partners • Johns Hopkins Univ. (J. Erlebacher) • Oak Ridge Nat’l Lab. (D. Cullen) • Lawrence Berkeley Nat’l Lab.(A. Weber) • Michigan Technological Univ. (J. Allen) • Freudenberg FCCT (C. Quick) • Argonne Nat’l Lab. (R. Ahluwalia) • Los Alamos Nat’l Lab. (R. Mukundan, R. Borup) • General Motors (B. Lakshmanan)
2
3M High Performance, Durable, Low Cost MEAs. 2014 DOE Hydrogen, Fuel Cells, Vehicles Program AMR, June 16-20
Objective and Relevance Overall Project Objective: Development of a durable, low-cost, robust, and high performance membrane electrode assembly (MEA) for transportation applications, able to meet or exceed the 2017 DOE MEA targets.
3
Primary Objectives and Approaches This Year
Barriers Addressed
1. Improve MEA Robustness for Cold Startup and Load Transient via Materials Optimization, Characterization and Modeling.
B. Cost C. Performance
2. Evaluate Candidate MEA and Component Durability to Identify Gaps; Improve Durability Through Material Optimization and Diagnostic Studies.
A. Durability
3. Improve Activity, Durability, and Rated Power of MEAs based on Pt3Ni7/NSTF Cathodes via Post-Processing Optimization and Characterization.
A. Durability B. Cost C. Performance
4. Integrate MEAs with High Activity, Rated Power, and Durability with Reduced Cost.
A. Durability B. Cost C. Performance
MEA, Catalyst Targets Addressed 2017 Targets Target Values Obj.
Q/∆T 1.45kW / °C 3,4
Cost $9 / kW 3,4
Durability with cycling
5000 hours w/ < 10% V loss 2,3,4
Performance @ 0.8V 0.300A/cm2 3,4
Performance @ rated power
1W/cm2 3,4
PGM Content (both electrodes)
0.125g/kWRATED 0.125mgPGM/cm2 3,4
3M High Performance, Durable, Low Cost MEAs. 2014 DOE Hydrogen, Fuel Cells, Vehicles Program AMR, June 16-20
Approach, Milestones, and Status v. Targets Approach: Optimize integration of advanced anode and cathode catalysts, based on 3M’s nanostructured thin film (NSTF) catalyst technology platform, with next generation PFSA PEMs, gas diffusion media, cathode interfacial layers, and flow fields for best overall MEA performance, durability, robustness, and cost. 1. Place appropriate emphasis on key commercialization and DOE barriers. 2. Through advanced diagnostics, identify mechanisms of unanticipated component interactions
resulting from integration of low surface area, low PGM, high specific activity electrodes into MEAs.
4
MS ID
Q T R
Project Milestone MS 1.1, 2.1, 5.1 based on 4-5 Project Goals
(See Backup Slides)
% Complete (Apr. ’14)
BUDGET PERIOD 1 (Sept. ‘12-May ‘14) 6.1 2 Baseline MEA: Short Stack Eval. Complete. CANCELLED 1.1 7 Comp. Cand. Meet Interim Perf./Cost Goals. 75% (3 of 4) 2.1 7 Comp. Cand. Meet Interim Cold-Start Goals. 75% (3 of 4) 5.1 7 Comp. Cand. Meet Interim Durability Goals. 66% (8 of 12)
3.1 7 GDL Pore Network Model Validation With ≥ 2 3M Anode GDLs. 50% (1 of 2)
6.2 7 Interim BOC MEA: Short Stack Eval. Complete. 10% (1 of 3)
4.1 Go/
No-Go 7
2014(Mar.) Best of Class MEA Meets G/NG 1) ≤ 0.135mgPGM/cm2 (Total) 2) Rated Power, Q/∆T: ≥0.659V@ 1.41A/cm2, 90ºC, 1.5atm H2/Air
100% 0.129mg/cm2
0.668V
Status Against DOE 2017 Targets
Characteristic 2017 Targets
Status, ’13/’14
Q/∆T (kW / °C) 1.45
1.56/1.56 (0.670V)
Cost ($ / kW) 9 6 / 5
(PGM only @ $35/gPt)
Durability with cycling (hours) 5000 NA
Performance @ 0.8V (mA/cm2) 300 203/125
Performance @ rated power (mW/cm2)
1000
871/932 (0.670V)
PGM total content (g/kW (rated))
0.125
0.157/0.138 (0.670V)
PGM total loading (mg PGM / cm2 electrode area)
0.125 0.137/0.129
3M High Performance, Durable, Low Cost MEAs. 2014 DOE Hydrogen, Fuel Cells, Vehicles Program AMR, June 16-20
Accomplishments and Progress
Improved Robustness for Cold Startup, Load Transient (Task 2): New Anode GDLs Improve Startup Capability - Higher H2O Removal Out Anode
5
• New anode GDL candidates show good promise for improving cold-start capability.
• Improvements in low T performance as the anode GDL is varied correlate with higher anode water removal rates @ 0.25A/cm2.
• As T decreases, performance loss occurs as anode water removal rate limit occurs.
30 35 40 45 50 550.0
0.3
0.6
0.9
1.2
1.5
D
C
B
A
J @
0.4
0V
(A
/cm
2)
Cell T (oC)
30/30/30C,
0/7.35psig H2/Air
800/1800SCCM,
PSS(0.40V, 10miN)
Temperature Sens. v. Anode GDL
Baseline
0.0 0.2 0.4 0.6 0.8 1.00.3
0.4
0.5
0.6
0.7
0.8Water Balance v. Anode GDL
D
C
BA
Ba
se
line
0.25A/cm2,CS2/2, 0/0psig,0% inlet RH
Ce
ll V
@ 0
.25
A/c
m2 (
Vo
lts)
Anode Total Removal Rate
(L/cm2/min)
35oC
0.0 0.2 0.4 0.6 0.8 1.00.3
0.4
0.5
0.6
0.7
0.8Water Balance v. Anode GDL
D
C
BA
Ba
se
line
0.25A/cm2,CS2/2, 0/0psig,0% inlet RH
Ce
ll V
@ 0
.25
A/c
m2 (
Vo
lts)
Anode Total Removal Rate
(L/cm2/min)
35oC
3M High Performance, Durable, Low Cost MEAs. 2014 DOE Hydrogen, Fuel Cells, Vehicles Program AMR, June 16-20
Accomplishments and Progress Cold Startup Modeling (Task 3): MTU Pore Network Model results validated against experimental liquid water transport in 3M GDL (Milestone)
6
Injection Pressure
Wetted Area
Pore Size Distribution
Contact Angle Model vs Experiment GDL “B” (prev. slide)
Energy/Time Scaling
MTU Model Inputs: • PSD, thickness, and contact angle • Operating conditions MTU Model Results: • Transient water distribution • Transient effective permeability,
conductivity, and diffusivity E. F. Médici and J. S. Allen, Phy. Fluids 23 (2011): 122107. E. F. Médici and J. S. Allen, Int. J. Heat Mass Trans., 65 (2013): 779-788.
3M High Performance, Durable, Low Cost MEAs. 2014 DOE Hydrogen, Fuel Cells, Vehicles Program AMR, June 16-20
Accomplishments and Progress
Cold Startup Modeling (Task 3): Possible Backing Structural Factor Identified
Which Correlates with Improved Low T Response; MTU Modeling Provides Insight
7
30 35 40 45 50 550.0
0.3
0.6
0.9
1.2
1.5
C
A
J @
0.4
0V
(A
/cm
2)
Cell T (oC)
30/30/30C,
0/7.35psig H2/Air
800/1800SCCM,
PSS(0.40V, 10miN)
Temperature Sens. v. Anode GDL
Baseline
• Some backings show apparent physical “banding” (dense/sparse regions) on ca. 1mm scale.
• Qualitative extent of banding correlates with improved low temperature performance.
• MTU model shows that banding can help retain higher gas permeability during simulated cold start and influences local catalyst temperature distribution.
Baseline
A
C
Incr
easi
ng
Den
sity
Mo
du
lati
on
Backlit Optical Microscopy
1 mm
0 50 100 150 20010
-15
10-14
10-13
10-12
10-11
C (Approximated)
A
Effective P
erm
eabili
ty B
(m
2)
Time (Sec)
Baseline
Influence of Dense/Sparse Backing
Alignment w/ FF Land/Channels
30oC, 60% RH, 1.5A/cm
2
50% heat,
80% water to cathode
Effective Permeability During
Simulated Cold Startup
3M High Performance, Durable, Low Cost MEAs. 2014 DOE Hydrogen, Fuel Cells, Vehicles Program AMR, June 16-20
Accomplishments and Progress
Improved Robustness for Cold Startup, Load Transient (Task 2): Cathode Interlayer Developed: 20C Improvement in Operating Window, and Is Durable
8
• Low loaded Pt/C interlayer (between NSTF cathode and cathode GDL) improves minimum “passing” load transient temperature: 50C (no IL) to 30C (w/ IL).
• Durability - Degradation of IL surface area w/ CV cycling results in improved MEA performance at rated power, and load transient is similar or improved.
30 40 50 60-0.2
0.0
0.2
0.4
0.6
0.8
1.0
30 or 40CoC, w/o IL
30oC, w/ IL
40oC, w/ IL
J
(A/c
m2)
or
V (
Volts)
Time (sec)
50oC, w/ or w/o IL
Benefit of IL, ~ 0.025mgPGM/cm2
xoC Cell, 50/50kPag H
2/Air, 0/0% RH, CS2/2 @ 1A/cm
2
Step J
Increase0
5
10
15
20Total Cathode Area (NSTF + IL)
Spec.
Are
a
(m2/g
)
PtCoMn/NSTF (no IL)
0.15mgPGM
/cm2
0.50
0.55
0.60
0.65High J H
2/Air Performance
V @
1.4
6m
A/c
m2
H2/A
ir,
(Volts)
80/68/680C
50/50kPag
CS2/2.5, 1.46A/cm2
0 1k 2k 3k0.0
0.1
0.2
0.3
0.4
33/0/00C, 50/50kPag H
2/Air,
696/1657SCCM, GSS(1A/cm2)
Ld T
rans V
(Volts)
# of V Cycles (0.6-1.2V, 100mV/s)
Ld Trans: 60s Ld Trans
32s
3M High Performance, Durable, Low Cost MEAs. 2014 DOE Hydrogen, Fuel Cells, Vehicles Program AMR, June 16-20
Accomplishments and Progress Component Durability Evaluation (Task 5): Component Candidates Generally Show Acceptable Durability; Cathode Cyclic Durability Insufficient
9
Metric Change/Tgt Mass Activity (A/mg) -66±4% / -40%
V @ 0.8A/cm2 -13±15mV/-30mV Surf. Area (m2/g) -28±4% / -40%
Electrocatalyst Cycle Support Cycle MEA Chemical
• Pt3Ni7 cyclic durability insufficient to achieve mass activity target; passes others. • Mostly Spec. Act. loss. • TEM, EDS (ORNL):
Modest coarsening and severe Ni loss.
Metric Change/Tgt Mass Activity (A/mg) -40±7 % / -40%
V @ 0.8A/cm2 -11±3 mV / -30mV Surf. Area (m2/g) -19±3% / -40%
• Pt3Ni7 cathode passes support cycle (previous 400hr 1.2V hold test).
Metric EOT / Target H2 Xover (mA/cm2) 3.7±0.3 / 2
OCV Loss (%) -6 ± 2 / -20 Short Res. (ohm-cm2) 1300±90 / 1000
• 2013 (March) BOC MEA passes (little change after 500 hours).
• 8 Candidates Evaluated (An., PEM, Cath.); All Pass if PEM Additive Present at Low Level.
0.0 0.5 1.0 1.50.50.60.70.80.91.0
Initial 400 Hours
Cell V
olta
ge (V
olts
)
J (A/cm2)
80/68/68C, 7.35/7.35psig H2/Air, CS(2,100)/CS(2.5, 167)GDS(0.02->2->0.02, 10steps/decade, 120s/pt, 0.4V limit, 0.1maxJstep)Upscan (high->low J) only.
0 200 400 6000.8
0.9
1.0
Time (hrs)
OCV
(Vol
ts)
90C, 30/30% RH1.5/1.5atm H2/Air
0.0 0.5 1.0 1.50.50.60.70.80.91.0 Initial
30k Cycles
Cell V
olta
ge (V
olts
)
J (A/cm2)
80/68/68C, 7.35/7.35psig H2/Air, CS(2,100)/CS(2.5, 167)GDS(0.02->2->0.02, 10steps/decade, 120s/pt, 0.4V limit, 0.1maxJstep)Upscan (high->low J) only.
3M High Performance, Durable, Low Cost MEAs. 2014 DOE Hydrogen, Fuel Cells, Vehicles Program AMR, June 16-20
Accomplishments and Progress MEA Rated Power Durability (Task 5): 3 Primary Factors To Date
10
Cell Temp (°C)
V @ 1A/cm2 Accel. Factor
80°C 0.6 90°C 1
100°C 4
Load Cycle Temp. PEM EW PEM Additive
PFSA EW (g/mol)
V @ 1A/cm2 Accel. Factor
1000 0.5 825 1 734 1.9
Add. Level (Arb.)
V @ 1A/cm2 Accel. Factor
1 1 0 10
0.5
0.6
0.7
0.8
0.9
1.0
0.0 0.5 1.0 1.50.5
0.6
0.7
0.8
0.9
1.0
No Additive
80/68/68C, 7.35/7.35psig H2/Air,
CS(2,100)/CS(2.5, 167)GDS(120s/pt)
BOT EOT
Cell
Volta
ge (V
olts
)
BOT EOTAdditive Level 1
Cell
Volta
ge (V
olts
)
J (A/cm2)
80/68/68C, 7.35/7.35psig H2/Air,
CS(2,100)/CS(2.5, 167)GDS(120s/pt)
0
5
10
15
0
10
20
30
0.50
0.55
0.60
0.65
0.70
SEF
(cm
Pt2 /c
m2 )
80oC 90oC 100oC
ORR
Abs
. Act
ivity
(mA/
cm2 )
Time
V @
1A/
cm2
(Vol
ts)
Method: Mod. Tech Team Load Cycle. Baseline: 0.05/0.15PtCoMn/NSTF, 825EW 20µ PEM, 90°C
0
5
10
15
0.500.550.600.650.70
0
10
20
30
1000EW 825EW 734EW
SEF
(cm
Pt2 /c
m2 )
Time
V @
1A/
cm2
(Vol
ts)
ORR
Abs
. Act
ivity
(mA/
cm2 )
Pt/NSTF on A+C
Pt/NSTF on A+C
3M High Performance, Durable, Low Cost MEAs. 2014 DOE Hydrogen, Fuel Cells, Vehicles Program AMR, June 16-20
Accomplishments and Progress
MEA Rated Power Durability (Task 5): Voltammetry Suggests Accumulation
of Anionic Contaminant; Rated Power Loss Due to ORR Kinetic Loss
11
• PEM EW, additive, and temp. factors, ORR Act. loss, and HUPD shift consistent: PEM decomp. cathode deact. rated power loss, due to “irreversibly” adsorbed PEM decomp. product(s).
• Species? CF3(CF2)nCOOH (small n), SO42- known reversible
contaminants for NSTF, Pt/C cathodes; why “irreversible” here?
• Can 20-30mV kinetic loss be related with 200mV loss at 1A/cm2? • Loss at 1A/cm2 (air) becomes exceptionally large as cathode ORR
activity (O2) decreases below ~10mA/cm2planar.
-0.002
-0.001
0.000
0.001
0.002
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8-0.002
-0.001
0.000
0.001
0.002
1000EW
825EW
734EW
70/70/70C, 0/0psig H2/N
2, 800/1800SCCM
CV(0.65V->0.085V->0.65V, 100mV/s)
Beginning of Test
1000EW
825EW
734EW
End of Test
Cathode E v. RHE (Volts)
70/70/70C, 0/0psig H2/N
2, 800/1800SCCM
CV(0.65V->0.085V->0.65V, 100mV/s)
J (
mA
/cm
2
pla
na
r)
0 5 10 15 20 25 300.2
0.3
0.4
0.5
0.6
0.7
0.8
BOL Only
Contam. Series
Ca. Ldg. Series
Model Fit
BOL and Degraded
EW Series
Temp Series
Additive Series
IR-F
ree
V @
1A
/cm
2
ORR Absolute Activity (mA/cm
2
planar)
V=V0+TS*log(AA
0/AA)
V0=0.76V (Fixed),
AA0= 26 +- 0.5 mA/cm
2
planar
TS=-0.122 +- 0.002 V/dec
R2=0.93
"Rated Power" Loss Due to ORR Kinetic Loss
214 Data Points, 53 MEAs
Correlation with both degraded and BOL MEAs with various BOL ORR activities.
53 MEAs
Mitigation Path: 1) Opt. Materials to Min. Contam. Generation 2) Recovery Method Development
HUPD E shift at EOT trends with performance loss.
3M High Performance, Durable, Low Cost MEAs. 2014 DOE Hydrogen, Fuel Cells, Vehicles Program AMR, June 16-20
Accomplishments and Progress Improved Activity, Rated-Power Capable ORR Catalysts (Task 1.1): SET (Annealing) Improves Activity, Area of Pt3Ni7/NSTF Cathodes
• Annealing optimization: • +30% mass activity, in MEA. • +20% specific area.
• DOE Mass Activity target exceeded.
• Increasing grain size, decreasing lattice constant (XRD) correlates with specific area gains. • Alloy homogenization,
defect reduction. • ORNL TEM: annealing
improves in-situ nanoporosity and increases Ni dissolution.
12
0.300.350.400.450.500.55
0 20 40 60 80 10012
14
16
18
20
ORR
Mas
s Ac
tivity
(A/m
g Pt)
SET Treatment Level (Arb. Units)
DOE2017
Target
Mas
s Sp
ecific
Surfa
ce A
rea
(m2 /g
)
3.66 3.67 3.68 3.69 3.7012
14
16
18
20
Mas
s Sp
ecific
Surfa
ce A
rea
(m2 /g
)
FCC Lattice Const (A)
Annealed Bulk Pt3Ni7
D. Cullen, ORNL
Pt77Ni23
Pt82Ni18
3M High Performance, Durable, Low Cost MEAs. 2014 DOE Hydrogen, Fuel Cells, Vehicles Program AMR, June 16-20
Accomplishments and Progress Improved Activity, Rated-Power Capable ORR Catalysts (Task 1.1): Substantially Increased Rated Power; Mass Activity Retained.
13
• JHU dealloying development has substantially increased rated power capability with Pt3Ni7 cathodes. • Best Chem/EC: +20/+40%% J @ 0.60V
• Optimization for volume production needed.
0.30
0.35
0.40
0.45
Mas
s Ac
t. (A
/mg)
As-Mad
e3M
BL
JHU Che
mJH
U EC12
14
16
18
Spec
. Are
a (m
2 /g)
Mass activity is retained after dealloying; small
area loss.
0.0 0.5 1.0 1.5 2.00.5
0.6
0.7
0.8
0.9
1.0
Best JHUEC Dealloy
To Date
Best JHUChem. Dealloy
To Date
3M BaselineDealloyedCe
ll Vol
tage
(Vol
ts)
J (A/cm2)
80/68/68C, 7.35/7.35psig H2/Air, CS(2,100)/CS(2.5, 167)GDS(0.02->2->0.02, 10steps/decade, 120s/pt, 0.4V limit, 0.1maxJstep)Upscan (high->low J) only.
Non-Dealloyed
Cathode: Pt3Ni7/NSTF, 0.125mgPt/cm2
3M High Performance, Durable, Low Cost MEAs. 2014 DOE Hydrogen, Fuel Cells, Vehicles Program AMR, June 16-20
Accomplishments and Progress Improved Activity, Rated-Power Capable ORR Catalysts (Task 1.1): Dealloying Transforms Pt3Ni7/NSTF Surface from NiOx to Pt Rich; Forms Nanoporosity
14
Scanning transmission electron microscopy (STEM) and X-ray
photoelectron spectroscopy (XPS) – ORNL, D. Cullen, H. Meyer
No Dealloy – Nonporous Pt3Ni7 with thin NiOx layer.
JHU Chem. Dealloy – Porous Pt42Ni58 with Pt enriched surface layer.
3M High Performance, Durable, Low Cost MEAs. 2014 DOE Hydrogen, Fuel Cells, Vehicles Program AMR, June 16-20
Accomplishments and Progress Best of Class Component Integration (Task 4.1): 2014 3M NSTF Best of Class MEA - High Rated Power and Mass Activity; G/NG Achieved
Go/No Go Metrics
Pre-Proj. Mar. ‘12
2014 BOC Mar. ‘14
≤0.135 mgPGM /cm2
0.151 0.129
≥0.659V @1.41A/cm2
0.609 0.668
Path to 2017 MEA Performance, Loading Targets: 1) Increase 0.80V H2/Air Activity (Min. Transport Loss; Increase Mass Activity > 0.5A/mg (anneal+dealloy))
2) Reduce HFR (Thinner, Low EW Supported PEM; GDLs; Interfacial R. Minimization).
15
Go/No Go Metrics Achieved
Key Improvements 1. Anode optimization to min. PGM. 2. Best practice cathode dealloying –
high J and 0.38A/mg mass activity. 3. Improved flow field w/ modestly
narrower lands, channels than FC Tech. Quad Serp. – in line with current trends.
4. 15% thinner PEM.
0.6
0.7
0.8
0.9
0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.000.000.050.10
G/NG
2014 Best of Class NSTF MEA - 0.129mgPGM/cm2 TotalAN.:0.019PtCoMn/NSTF. CATH.:0.11Pt3Ni7 (DEALLOY). PEM: 3M 20µ 850EW. GDL: 2979/2979.
2014 BOC MEA0.129mgPGM/cm2
Pre-Contract Status2012 BOC MEA0.151mgPGM/cm2
90/84/84C, 7.35/7.35psig H2/Air, CS(2,100)/CS(2.5, 167)GDS(0.02->2->0.02, 10steps/decade, 120s/pt, 0.4V limit, 0.1maxJstep)High->low J OnlyOUTLET P CONTROL
Cell V
olta
ge(V
olts
)
Kinetic+HFR Only Pol. CurveThrough 1/4 Power, Rated Power,
and Q/∆T(90oC) Targets
HFR Needed to Achieve Target
J (A/cm2)
HFR
(ohm
-cm
2 )
3M High Performance, Durable, Low Cost MEAs. 2014 DOE Hydrogen, Fuel Cells, Vehicles Program AMR, June 16-20
Accomplishments and Progress Best of Class Component Integration (Task 4.1): PGM, Rated and Specific Power Targets Approached @ 150kPa, 0.67V ; All 2017 MEA Perf. Targets @ 250kPa
16
• Steady improvement in total PGM, rated power, and specific power.
• At 150kPa, within 10% of 4 DOE 2017 targets @ 0.67V.
• At 250kPa, all 2017 performance targets approached or achieved.
Characteristic Unit Target Value @ 150kPa Performance @
0.80V mA/cm2 ≥300 125 (~190 w/ low RH)
Q/∆T kW/°C ≤ 1.45 1.56 (0.67V,90°C)
(+20mV @ 90°C) or (+4°C @ 0.67V)
Performance @ rated power mW/cm2 ≥ 1000 932 (0.67V)
Specific Power g/kW ≤ 0.125 0.138 (0.67V) PGM Content mg/cm2 ≤ 0.125 0.129
Value @ 250kPa
285
1.42 (0.70V,90°C)
1020 (0.70V)
0.127 (0.70V) 0.129
0.0 0.5 1.0 1.50.6
0.7
0.8
0.9
2014(March) BOCMEA @ 90oC, 250kPa
J (A/cm2)
Model Curve which meetsRated Power, Specific Power,Q/∆T, & 1/4 Power 2017 Tgts
"Rated Power"1.46A/cm2
@ 0.699V90/76/76C, CS2/2.5 H2/Air, 120s/pt
2012
(Marc
h)
2012
(Sep
t)
2013
(Marc
h)
2013
(Dec
)
2014
(Mar)
DOE 2017
Tgt0.10
0.15
0.20
0.250.6
0.8
1.0
1.2
1.40.10
0.12
0.14
0.16
Target0.125g/kW
250200150
Spec
ific P
ower
(g
PGM/k
W) @
0.6
7V
P(kPa)
Target1W/cm2
250200
150Rate
d Po
wer
W/c
m2 @
0.6
7V
P(kPa)
Target0.125mg/cm2To
tal P
GM
(mg/
cm2 )
3M High Performance, Durable, Low Cost MEAs. 2014 DOE Hydrogen, Fuel Cells, Vehicles Program AMR, June 16-20
Response To Reviewers’ Comments Addressing NSTF MEA Operating Condition and Impurity Sensitivities • “…project is limited to "optimization of existing components and processes" and … "NO COMPONENT
DEVELOPMENT." … unfortunate, since what is required … is … a new catalyst layer architecture.” • “major barrier to commercialization of NSTF is the high sensitivity to operating conditions, yet …
progress on these tasks is delayed or not even started.” • “…NSTF MEAs … extremely sensitive to both temperature and impurities relative to conventional MEAs.” •Component development not allowed in Topic 4 of 2011 FOA. New catalyst layer architecture could require its own project. We believe current Task 2+3 approach will be sufficient. •Work to address operating temp. sensitivity was in progress prior to AMR, but was too early in development for reporting. We agree, this is a key issue and is actively being addressed. •To our understanding, impurity sensitivity is proportional to surface area. Pt3Ni7/NSTF surface areas are increasing under Task 1, and added area from Task 2 interlayers should help.
OEM Participation; Validation in Stacks • “…3M has a history of showing great lab results that do not translate well to practical stacks…” • “… good … to see what stack formats and operating conditions will be used for…integration activities.“ • “For a ... (MEA) project, it is extremely surprising to see that the list of collaborators does not include a
stack developer (either automotive or otherwise).” • General Motors is the project partner responsible for stack testing, but wasn’t finalized until
after last year’s AMR. • We agree that integration into stacks is important. Cold-startup is much less challenging
with low heat capacity stacks than estimates from single cells. Stack optimization to enable demonstrated NSTF MEA rated power capability is necessary, but not in project scope.
17
3M High Performance, Durable, Low Cost MEAs. 2014 DOE Hydrogen, Fuel Cells, Vehicles Program AMR, June 16-20
Collaborations Johns Hopkins University (Jonah Erlebacher) – Subcontractor •Task 1 - Pt3Ni7/NSTF dealloying optimization. Oak Ridge National Laboratory (David Cullen) – Subcontractor •Task 1 - Characterization of dealloy/SET post-processed Pt3Ni7/NSTF cathodes. Freudenberg FCCT (Christian Quick) – Vendor •Task 2 – Experimental anode GDL backings. Michigan Technological University (Jeffrey Allen) – Subcontractor •Task 3 -GDL char.; Integration of 3M anode GDLs into MTU pore network model. Lawrence Berkeley National Laboratory (Adam Weber)–Subcontractor •Task 3 - GDL char.; Integ. MTU PNM into LBNL MEA model; Cold startup modeling. Argonne National Laboratory (Rajesh Ahluwalia) – Collaborator •Task 4 - NSTF BOC MEA HOR/ORR kinetic char. studies; FC systems modeling. Los Alamos National Laboratory (Mukundan, Borup) – Subcontractor •Task 5 – Load cycle durability evaluation General Motors (Balsu Lakshmanan) – Subcontractor •Task 6 – Short stack evaluation.
18
3M High Performance, Durable, Low Cost MEAs. 2014 DOE Hydrogen, Fuel Cells, Vehicles Program AMR, June 16-20
Key Future Work – FY14, FY15 Task 1 – Integration Activities Toward ¼ Power, Performance @ rated power… •Demonstrate Scale-up Feasibility of Downselected Dealloying, Annealing Methods •Integration of Next Generation Supported, Low EW PEMs
Task 2 - Integration …. Transient Response, Cold Start Up … •Continued Anode GDL and Cathode Interlayer Optimization; Diagnostic Studies.
Task 3 - Water Management Modeling for Cold Start • Finalize GDL Modeling @ MTU, Integrate MTU-LBNL Models→ Identify Key A. GDL Factors.
Task 4 - Best of Class MEA Integration Activities •Best of Class Component Integration Towards Project Goals: (≤ 0.125mgPGM/cm2; Rated Power, Q/∆T: 0.709V @ 1.41A/cm2 @ 90°C).
•Improvement in Cathode Activity, Durability Critical
Task 5 - Durability Evaluation and Performance Degradation Mitigation •Evaluation of New Cathodes (as available) to Achieve Electrocatalyst Durability Targets. •Irreversible Peak Power Loss Mitigation (Material Optimization; Recovery Methods)
Task 6 - Short Stack Performance, Power Transient, and Cold Start Evaluation • Achieve Required Robustness Metrics Through Incorporation of Improved Anode GDLs, Cathode Interlayers, and Next Generation PEMs. •Implement Short Stack Testing of Interim and Final Project Best of Class MEAs.
19
3M High Performance, Durable, Low Cost MEAs. 2014 DOE Hydrogen, Fuel Cells, Vehicles Program AMR, June 16-20
Summary
20
Operational Robustness (Cold Start; Load Transient) • Experimentally confirmed operational mechanism of cold-startup variation with
anode GDL backings. MTU GDL model experimentally validated w/ one project GDL to date. Benefits of sparse/dense GDL structures becoming evident.
• Cathode interlayer developed which improves load transient operating window by 20°C and has good durability and low PGM prospects.
Durability (MEA Load Cycling; MEA Chemical; Cathode) • Key mechanism of rated power loss identified – development direction for
improvement is forming. LANL onboarding into task has occurred smoothly. • MEA chemical durability of all components appears sufficient. • Cathode mass activity durability insufficient; being addressed outside project.
Power, Cost (Cathode Post Processing; Best of Class MEA Integration) • Annealing: 30% mass activity gain, via method development and improved
structural understanding. Dealloying: +20-40% lim. J over baseline method. Annealing & Dealloying integration, process feasibility are key next steps.
• MEA integration - substantial gains in specific power (+47% kW/g v. pre-proj.) due to improved absolute performance and PGM reduction towards target. Path to 2017 targets identified. Go/No Go Performance and Loading Metrics Achieved.
21
Technical Back-Up Slides
Instruction
3M High Performance, Durable, Low Cost MEAs. 2014 DOE Hydrogen, Fuel Cells, Vehicles Program AMR, June 16-20
Target Polarization Curve Calculation
• Polarization curves calculated which simultaneously meet ¼ power, Q/∆T, and rated power targets.
• Required performance decreases as cell temperature increases to 88°C (Q/∆T)
• Q/∆T target puts strict requirements on: • Cell T (≥88°C) • HFR (≤0.04ohm-cm2)
• Peak power (1W/cm2)
occurs at < 1.5A/cm2 and >0.70V.
0.00 0.25 0.50 0.75 1.00 1.25 1.500.5
0.6
0.7
0.8
0.9
1.0
88C and Hotter
85C
Target Performance @ 80C Target performance @ 85C Target performance @ 90C Target performance @ 95C
C:\Users\us314230\Documents\DOE6\FC23951_LowTotalLoadingPt3Ni7-[Graph12]
Cell V
olta
ge (V
olts
)
J (A/cm2)
Performance Needed To Simultaneously Achieve DOE2017 MEA Targets At Various Cell Temperatures
For T>90C, increasing temperature just decreases Q/dT furtherFor T<90C, kinetics must increase to increase cell V at peak power
J, V to Achieve Rated Power, Q/dT, 1/4 Power Targets80C: 1.31A/cm2 @ 0.761V. 0.760A/cm2 @ 0.80V85C: 1.37A/cm2 @ 0.725V. 0.417A/cm2 @ 0.80V.90C: 1.41A/cm2 @ 0.709V. 0.301A/cm2 @ 0.80V95C: 1.41A/cm2 @ 0.709V. 0.301A/cm2 @ 0.80V
80C
Targets Addressed: J @ 1/4 Power (0.8V, 0.30A/cm2), Rated Power (1W/cm2), and Q/∆T (1.45kW/degC)Model Assumptions: HFR: 0.04ohm-cm2, Tafel: 70mV/dec, No MTO, 90kW Stack
JRJJLOGVV −
−=
00 07.0
CTV
VkW
TQ
rated
rated
rated
40
25.190
−
−∗
=∆
22
3M High Performance, Durable, Low Cost MEAs. 2014 DOE Hydrogen, Fuel Cells, Vehicles Program AMR, June 16-20 23
0.0 0.2 0.4 0.6 0.8 1.0 1.20.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0Anode: 0.20PtCoMn/NSTF. Cathode: 0.20PtCoMn/NSTF.
PEM: 3M/G. GDL: 2975/2975
After 8550hrs
Initial
Ce
ll V
(V
olts),
HF
R (
oh
m-c
m2)
J (A/cm2)
FC12682 315.DAT NFAL (INITIAL)
FC12682 321.DAT NFAL
FC12682 712.DAT NFAL
Peformance After ~ x hours on Shiva, FC12682
80/80/80C, 0/0psig inlet, CF696/1657 H2/Air
GDS(0.0A/cm2->0.40V->0.0A/cm
2, 0.05 or 0.025A/cm
2/step, 20s/step)
After 3800hrs
Predicted Loss
0 2 4 6 8 10 12 140.0
0.5
1.0
1.5
2.0
0.0 0.5 1.0 1.5 2.00.5
0.6
0.7
0.8
0.9
0.0 0.5 1.0 1.5 2.00.5
0.6
0.7
0.8
0.9Limiting Current v. Cathode Surface Area
J @
0.5
0V
(A
/cm
2)
Cathode Catalyst Pt Surface Area
(cm2-Pt/cm
2-planar)
7200A PR
Initial Performance
1.2V CV Cycling, 95C
1.2V CV Cycling, 80C
80C Load Cycling (After Several 1000hrs)
Gas Replace Test
USFCC
Black Squares: Initial
Colored: After Durability
C
0.05/xPtCoMn/NSTF
3M 850EW Unsupported
0.05/xPtCoMn/NSTF
3M 850EW Unsupported
A
BOL Pol. Curves v. Support Area
0.05mgPt/cm
2
NSTF (5.8)
0.10mgPt/cm
2
NSTF (9.1)
Ce
ll V
(V
olts
)
J (A/cm2)
BOL Pol. Curves v. Loading
B
"Bad Support"
0.10mgPt/cm
2
NSTF (3.2)
"Good Support"
0.10mgPt/cm
2
NSTF (9.5)
Ce
ll V
(V
olts
)
J (A/cm2)
80/68/68C, 150/150kPa H2/Air, CS2/2.5 GDS (OCV->lim->OCV, 120s/pt)
• While PtCoMn/NSTF surface area is relatively stable, MEA performance degradation under H2/Air load cycling can be substantial. • Much larger than kinetic (70mV/dec)
and ohmic losses predict. • Appears irreversible – thermal cycling,
high E scans, … ineffective to date towards fully recovering performance.
Factors 1. H2/Air performance sensitivity to
cathode surface area (< 9cm2/cm2) 2. Previous work by collaborator
suggested 2nd possible mode, related to PEM degradation catalyst contamination.
BOL and Durability Aged Historical H2/Air Performance w/
80C Load and RH Cycling, 8500 hours 1000EW PEM, 0.20PtCoMn/NSTF on A+C
MEA Rated Power Durability – Background
3M High Performance, Durable, Low Cost MEAs. 2014 DOE Hydrogen, Fuel Cells, Vehicles Program AMR, June 16-20
2014 (March) Best of Class MEA – Kinetic Analysis
• Recent BOC MEA candidates show surprisingly strong H2/Air kinetic performance sensitivity to RH.
• Significant kinetic gains occur as RH is reduced below BOC test conditions (which are optimized for high J) – suggests possible O2 transport issue at cathode. • Low heat generation rates- waste heat aids
thermal gradient driven water removal. • Development in progress to improve kinetic
response under H2/Air via operational and material approaches.
Best of Class MEA H2/Air Kinetics, Mass Activities
MEA
H2/Air J @ 0.80V
(A/cm2
H2/O2 ORR Mass
Activity (A/mg)
Ca. PGM (mg/cm2)
2012 (March) 0.19 0.37 ± 0.01 0.121
2014 (March) 0.125 0.38 ± 0.02 0.110
0.0 0.1 0.2 0.3 0.40.70
0.75
0.80
0.85
Cell V
olta
ge (V
olts
)
J (A/cm2)
FC30550 531-637.RAW 80C FC30550 531-637.RAW 68C FC30550 531-637.RAW 61C FC30550 531-637.RAW 59C FC30550 531-637.RAW 53C FC30550 531-637.RAW 42C
80/x/xC, 7.35/7.35psig H2/Air, CS(2,100)/CS(2.5, 167)GDS(0.3->0.1, 0.05/step, 120s/pt) w/ 0.65V Precondition
Kinetic RHSens for Dealloyed Pt3Ni7 in FF2
~BOC TestCondition
When measured under “Best of Class” test conditions, 2014(March) BOC MEA
showed substantial decrease in ¼ Power Performance compared to 2012 MEA, but
mass activity relatively unchanged.
24
60 80 100 1200.000.050.100.150.200.25
60 80 100 1200.740.750.760.770.780.790.80
90oC Cell, 7.35/7.35psig H2/Air (OUTLET), CS(2,100)/CS(2.5, 167)
J (A
/cm
2 ) @ 0
.80V
Calc. Outlet RH (%)
FC029436 FC029489
Extracted from Pol. Curves,
Best Of ClassTesting RH
V @
0.3
0A/c
m2
(Vol
ts)
Calc. Outlet RH (%)
FC30392 V @ 0.3A/cm2March('14) BOC
y
Stable Valuesfrom 30minGSS Holds)
Best Of ClassTesting RH
3M High Performance, Durable, Low Cost MEAs. 2014 DOE Hydrogen, Fuel Cells, Vehicles Program AMR, June 16-20
Task 6 – Short Stack Evaluation – Robustness Metrics
1070 1080 1090 1100 1110-0.2
0.0
0.5
1.0 30/25/25C,
x/150kPa H2/Air,
522/1491SCCM
(CS1.5/1.8 @ 1A/cm2)
Cell V too low,
station reset to OCV
Initiate Fast
Step Up to
1A/cm2
30/25/25C,
x/150kPa H2/Air,
522/1491SCCM (CS1.5/1.8 @ 1A/cm2)
1) 1.0A/cm2, 15min
2) 0.1A/cm2, 3min
3) 0.25A/cm2, 1s
4) 0.50A/cm2, 1s
5) 0.75A/cm2, 1s
6) 1.00A/cm2, 1min
J (
A/c
m2),
V (
Vo
lts)
Time (sec)
FC30114 502-507.RAW Current Density Measured
V, 150kPa
V, 125kPa
V, 100kPa
Transient Sensitivity Test, x/150kPa
J (A/cm2)
Cell V
"Almost"
Recovery
w/ 100kPa
Anode
0 10 20 30-0.2
0.0
0.5
1.0
1) 1.0A/cm2, 15min
2) 0.1A/cm2, 3min
3) 0.25A/cm2, 1s
4) 0.50A/cm2, 1s
5) 0.75A/cm2, 1s
6) 1.00A/cm2, 1min
J (
A/c
m2),
V (
Vo
lts)
Time (sec)
FC30114 502-507.RAW Current Density Measured
V, 150kPa
V, 125kPa
V, 100kPa
Steady State Sensitivity Test, x/150kPa
J (A/cm2)
Cell V @ 150, 125, 100kPa Anode
Cell V too low,
station reset to OCV
30/25/25C,
x/150kPa H2/Air,
522/1491SCCM (CS1.5/1.8 @ 1A/cm2)
• NSTF MEA w/ interim downselect anode GDL, cathode interlayer from Task 2 “almost” passes cold operation and cold transient tests (above).
• Easily passes Hot Operation test (right).
Cold Operation Test v. PA Cold Transient Test v. PA
0 10 20 300.0
0.5
1.0
0 10 20 3075
80
85
90
95
HFR
90C Cell
VAvg: 0.648V
x/59/59C, 150/150kPa H2/Air,
CS(1.5,100)/CS(1.8, 167)
GSS(1)
J (
A/c
m2
), V
(V
olts),
HF
R (
oh
m-c
m2)
80C Cell
VAvg: 0.642V
J
Ce
ll T
(d
eg
C)
Time (min)
FC30114 543-544.RAW Cell Temperature Measured
Hot Robustness Test, Trial 1
CCM: 0.05PtCoMn/0.15PtCoMn, 3M 20u 825EW Anode GDL: X+PTFE, MPL (interim DS). Cathode IL: 2979+ “B” IL @ ca. 0.03mgPt/cm2(interim DS)
25
3M High Performance, Durable, Low Cost MEAs. 2014 DOE Hydrogen, Fuel Cells, Vehicles Program AMR, June 16-20 26
Cold Startup: Effective Properties
Model prediction and experimental measurement [1] of effective thermal conductivity for a dry GDL under strain. MTU Pore Network Model accounts for change in contact resistance due to GDL compression.
Effective Thermal Conductivity
Freudenberg H2315 at 1.5A/cm2
with 50% heat and 80% water on cathode for a range of conditions. Steady-state effective permea-bilities were also calculated for Toray T060 and found to corre-spond to experimental values [2].
Transient Effective Permeability Transient Effective Diffusivity
Toray T060 w/ and w/o MPL on cathode side at 1.5A/cm2 with 50% heat and 50% water.
Cold Startup Modeling (Task 3): MTU Pore Network Model Calculations of GDL Effective Properties.
1. Burheim, Pharoah, Lampert, Vie, and Kjelstrup, J. Fuel Cell Sci. Tech., 8(2): 021013 (2011) 2. Gostick, Fowler, Pritzker, Ioannidis, and Behra, J. Power Sources ,162(1): 228-238 (2006)
Top Related