mea & dm characterization/optimization for low pt loadings ... · 11/15/2017 · 5% pt/vu a pt...
TRANSCRIPT
Chair of Technical Electrochemistry
Technical University of Munich, Germany
PEM fuel cell materials / structures
Pt reduction strategies:
- Pt needs for the HOR
- ORR catalyst status / limitations
- mass-tx loss phenomena
- MPL/DM design for high-i
- effect of catalyst morphology
Summary
MEA & DM Characterization/Optimization
for Low Pt Loadings and High Current Densities
page 1 11/15/2017 Hubert Gasteiger | Chair of Technical Electrochemistry | Technical University of Munich
G.S. Harzer, C. Simon, A. Orfanidi, P. Madkikar, H.A. El-Sayed, H.A. Gasteiger
Fuel Cell Electric Vehicle Challenges
since 2008: >300 mi. range 70 MPa H2 (4-6 kgH2 at 5%wt) with refuelling <5 mins.
catalyst cost & supply (100kW car):
current: 0.3-0.5 gPt/kW 30-50gPt/car
5-10x vs. automotive emission catalysts
long-term: <0.1gPt/kW <10gPt/car
large-scale commercial viability
H2 generation & distribution infrastructure...
approaches to get to <0.1 gPt/kW ?
page 2 11/15/2017 Hubert Gasteiger | Chair of Technical Electrochemistry | Technical University of Munich
Membrane Electrode Assembly
Diffusion Media (DM)
Diffusion Media (DM)
Bipolar Plate (BP)
Bipolar Plate (BP)
20-40 cm
1 mm
C-fiber paper
(7 mm fibres)
Mathias, Roth, Fleming,
Lehnert; in: Handbook of
Fuel Cells; Wiley, vol. 3
(2003) chapter 46
high electronic Rcontact
H2/Air Fuel Cell Components
O2
RO2-tx
Baker, Caulk, Neyerlin, Murphy;
J. Electrochem. Soc. 156
(2009) B991
page 3 11/15/2017 Hubert Gasteiger | Chair of Technical Electrochemistry | Technical University of Munich
membrane
H+
e-
O2
O2 + 4H+ + 4e- 2H2OPt
Diffusion
Medium
membrane
H+
e-
O2
O2 + 4H+ + 4e- 2H2OPt
O2 + 4H+ + 4e- 2H2OPt
O2 + 4H+ + 4e- 2H2OPt
Diffusion
Medium
PEFC Electrode Composition / Structure
dominated by carbon-black structure
40 nm
46% Pt/carbon
40 nm
46% Pt/carbon Pt/C & ionomer at 1 gionomer/gcarbon
60% void volume (dpore 50-100 nm)
from: Z.Y. Liu, B.K. Brady,
R.N. Carter, B. Litteer, M. Budinski,
JECS 155 (2008) B979
H+-tx resistance (RH+-tx) in electrodes*)
assumes homogenous ionomer distr.
*) Y. Liu, M.W. Murphy, D.R. Baker, W. Gu, C. Ji, J. Jorne,
H.A. Gasteiger; J. Electrochem. Soc. 156 (2009) B970
page 4 11/15/2017 Hubert Gasteiger | Chair of Technical Electrochemistry | Technical University of Munich
page 5 11/15/2017 Hubert Gasteiger | Chair of Technical Electrochemistry | Technical University of Munich
PEM fuel cell materials / structures
Pt reduction strategies:
- Pt needs for the HOR
- ORR catalyst status / limitations
- mass-tx loss phenomena
- MPL/DM design for high-i
- effect of catalyst morphology
Summary
high transport-limited current 80 A/cm2 at 100 kPaabs H2
HOR/HER Kinetics via PEM H2-Pump
2 mgmetal/cm2 0.4 mgPt/cm2
working electrode counter & reference
electrode m
em
bra
ne
DM DM
determination of transport-resistance-free HOR/HER kinetics
( K.C. Neyerlin, W. Gu, J. Jorne, H.A. Gasteiger, J. Electrochem. Soc. 154 (2007) B631)
H2-pump: minimized ohmic /transport losses & maximized kinetic resistance
- thin membrane (20mm) and electrode (2mm)
minimize ohmic losses
- ultra-low Pt loading on working electrode
increase kinetic resistance
page 6 11/15/2017 Hubert Gasteiger | Chair of Technical Electrochemistry | Technical University of Munich
HOR Kinetics on Pt/C
HOR kinetics on Pt/C (100 kPaa H2, 100%RH)
for h>100 mV: Tafel-reaction limited
(itx-limit > 50 A/cm2geo)
for h<50 mV: Tafel/Volmer(rds)
5% Pt/Vu
APt = 100 m2/gPt
LPt = 2 mgPt/cm2geo
gas-phase H2 dissociation rate const.1) :
kH2/D2 = 2.4 cm/s at 295 K
≡ ”Tafel” reaction: H2 2 Had
with iTafel 0.5 A/cm2Pt
1) Vogel, Lundquist, Ross, Stonehart,
Electrochim. Acta 20 (1975) 79
on Pt/C at 353 K2) : - i0 ≈ 0.3 A/cm2
Pt
- αa = αc = 0.5 ≡ 140 mV/dec.
a cF F
R T R T0i i rf e e
h h
fit to:
Had H+ + e-
page 7 11/15/2017 Hubert Gasteiger | Chair of Technical Electrochemistry | Technical University of Munich
from: Durst, Simon, Hasché, Gasteiger, J. Electrochem. Soc. 162 (2015) F190
HOR Kinetic Losses on Pt/C in PEMFC
predicted hHOR/HER at igeo = 3 A/cm2geo & 0.05 mgPt/cm2 (80C and 100 kPaabs H2) ?
for typical Pt/C catalyst:
APt = 80 m2
Pt/gPt 800 cm2Pt/mgPt
rf = 40 cm2Pt/cm2
geo
required kinetic current:
ik = igeo / rf = 0.7510-2 A/cm2
Pt
hHOR <10 mV at 0.05 mgPt/cm2 even at very low Pt anode loadings
page 8 11/15/2017 Hubert Gasteiger | Chair of Technical Electrochemistry | Technical University of Munich
H2 Oxidation Reaction (HOR) Kinetics on Pt/C
H2 2 H+ + 2 e
- kinetics via rotating disk electrode (RDE) in liquid electrolytes
but, slow H2-transport
fast transport in liquid electrolytes:
- Floating VCF Pt/C Electrode3)
- Scanning Electrochemical
Microscopy (SECM) on Ptpc4)
- Ultra Micro Electrode (UME)5)
1) J. Durst, C. Simon, F. Hasché, H. A. Gasteiger, J. Electrochem. Soc. 162 (2015) F190 2) J. Durst, A. Siebel, C. Simon, F. Hasché, J. Herranz, H. A. Gasteiger, Energy Environ. Sci. 7 (2014) 2255
i0 (RDE) 102-fold too low
fast HOR/HER kinetics
very fast transport in PEM setup:
H2-pump measurements1,2)
3) C.M. Zalitis, D. Kramer, A.R. Kucernak, Phys. Chem. Chem. Phys. 15 (2013) 4329 4) J. Zhou, Y. Zu, A.J. Bard, J. Electroanal. Chem. 491 (2000) 22 5) V. Bagotzky, N. Osetrova, J. Electroanal. Chem. 43 (1973) 233
page 9 11/15/2017 Hubert Gasteiger | Chair of Technical Electrochemistry | Technical University of Munich
PEM fuel cell materials / structures
Pt reduction strategies:
- Pt needs for the HOR
- ORR catalyst status / limitations
- mass-tx loss phenomena
- MPL/DM design for high-i
- effect of catalyst morphology
Summary
page 10 11/15/2017 Hubert Gasteiger | Chair of Technical Electrochemistry | Technical University of Munich
H2/Air PEMFC Performance Model
0.60
0.65
0.70
0.75
0.80
0.85
0.90
0.0 0.3 0.6 0.9 1.2 1.5 [A/cm2]
Vo
ltag
e (
V)
Ecell
hHFR=90 mV (hmem=30 mV)
ST19-S0559 (Nano-x coating) RC FCPM op-line
MEA: Gore 5720 (18 mm, 0.2/0.3 mgPt/cm2, I/C=1.2)
DM/MPL: Pre-compressed SGL 25BC
htx,O2(dry)=26 mV
hORR=410 mV
htx,H+ =18 mV
htx,O2(wet)=18 mV
Pt
2
PtMEA
2
MEA
mg0.45
gcm0.5
W kW0.9
cm
at 1.5 A/cm2:
H2/air (s=1.5/2), 150kPaabs, <50% RHinlet
25mm membrane and 0.05/0.40 mgPt/cm2MEA
( 60 mV Rcontact)
from: W. Gu, D.R. Baker, Y. Liu, H.A. Gasteiger, in:
Handbook of Fuel Cells, Wiley (2009): vol. 6, pp. 631.
( hHOR < 5 mV*) )
need 10x better ORR catalysts to reach 0.05/0.04 mgPt/cm2MEA 0.1 gPt/kW
O2 + 4 H+ + 4 e
- 2 H2O
page 11 11/15/2017 Hubert Gasteiger | Chair of Technical Electrochemistry | Technical University of Munich
Fuel Cell Cathode Catalyst Options
options envisaged in 2009: ultra-high activity Pt-based or Pt-free
TOF at 0.8V RHE 4) (80°C, 100kPa O2)
from: H.A. Gasteiger & N.M. Marković; Science 324 (2009) 48
page 12 11/15/2017 Hubert Gasteiger | Chair of Technical Electrochemistry | Technical University of Munich
de-alloyed Pt-alloys1): leaching of Ni-rich Pt-Ni alloys
proven in fuel cell stacks: 0.4-0.6 A/mgPt
shape-controlled Pt-alloys2):
2) C.Chen, Y. Kang, Z. Huo, Z. Zhu, W. Huang, H.L. Xin, J.D. Snyder, D. Li, J.A. Herron,
M. Mavrikakis, M. Chi, K.L. More, Y. Li, N.M. Markovic, G.A. Somorjai, P. Yang, V.R. Stamenkovic; Science 343 (2014) 1339
Pt3Ni octahedra Pt3Ni nanoframes
highest activity for C-supported catalysts so far
O2 Reduction Reaction (ORR) Catalysts
1) B. Han, C.E. Carlton, A. Kongkanand, R.S. Kukreja, B.R. Theobald, L. Gan, R. O’Malley, P. Strasser, F.T. Wagner, Y. Shao-Horn; Energy Environ. Sci. 8 (2015) 258
page 13 11/15/2017 Hubert Gasteiger | Chair of Technical Electrochemistry | Technical University of Munich
FC Cathode Catalyst Roadmap (2015)
from: O. Gröger, H.A. Gasteiger,
P.-J. Suchsland, J. Electrochem.
Soc. 162 (2015) A2605
likely ORR catalyst candidates for applications (green) & new concepts (white)
3-4x catalysts (0.4-0.6 A/mgPt) feasible for next gen. FCEVs
sufficient for reaching <0.1 gPt/kW target ?
page 14 11/15/2017 Hubert Gasteiger | Chair of Technical Electrochemistry | Technical University of Munich
page 15 11/15/2017 Hubert Gasteiger | Chair of Technical Electrochemistry | Technical University of Munich
PEM fuel cell materials / structures
Pt reduction strategies:
- Pt needs for the HOR
- ORR catalyst status / limitations
- mass-tx loss phenomena
- MPL/DM design for high-i
- effect of catalyst morphology
Summary
Best-Case High-i Performance Limit
projected performance without ‘film resistance’: - im = 0.4 A/mgPt (Pt-alloy)
- Lan/ca = 0.05/0.05 mgPt/cm2
- tmembrane = 10 mm (0.1 S/cm)
- Rcontact = 15 mWcm2
- rH+,cath. = 50 Wcm (10 mm thick)
- RO2-tx = 0.5 s/cm (for DM only)
- hHOR negligible (<10mV)
0.06 gPt/kW at 0.60 V
would meet DOE target, if
low-Pt cathodes can be made
low Rcontact & low RO2-tx req.
0.50
0.55
0.60
0.65
0.70
0.75
0.80
0.85
0 1 2 3 i [A/cm2]
E [
V]
H2/air (150kPaabs), 80ºC, 100%RHmembrane
page 16 11/15/2017 Hubert Gasteiger | Chair of Technical Electrochemistry | Technical University of Munich
Low-Pt Cathode – Surface Film Resistance
additional O2 transport resistance
found for low-loaded Pt cathodes
from: J.P. Owejan, J.E. Owejan, W. Gu;
J. Electrochem. Soc. 160 (2013) F824
htx-film for >0.02 A/cm2Pt at 150 kPaa H2/air
ascribed to interfacial resistance from: A. Kongkanand, M.F. Mathias;
J. Phys. Chem. Lett. 7 (2016) 1127
page 17 11/15/2017 Hubert Gasteiger | Chair of Technical Electrochemistry | Technical University of Munich
htx-film
H2/air (150kPaabs)80ºC/100%RH
H2/air at 100 kPaa
and 80C/100% RH
0.05 mgPt/cm2cathode
Low-Pt Cathode – Pt/Support Morphology
effect of catalyst morphology on Pt mass activity and H2/air performance
poor high-i performance of burried Pt lower ORR poisoning by burried Pt
from: Y.-C. Park, H. Tokiwa, K. Kakinuma, M. Watanabe, M. Uchida, J. Power Sources 315 (2016) 179
page 18 11/15/2017 Hubert Gasteiger | Chair of Technical Electrochemistry | Technical University of Munich
controlled by
carbon morphology*)
carbon-support vs. Pt deposition method ?
page 19 11/15/2017 Hubert Gasteiger | Chair of Technical Electrochemistry | Technical University of Munich
PEM fuel cell materials / structures
Pt reduction strategies:
- Pt needs for the HOR
- ORR catalyst status / limitations
- mass-tx loss phenomena
- MPL/DM design for high-i
- effect of catalyst morphology
Summary
Micro-Porous-Layer (MPL) Design
Denka carbon black Li100 Li400
Primary particle size (spec.) [nm] 35 48
BET – surface powder [m2/g] 64 37
DBP absorption [ml/100g] 175 140
- MPLs with 20 wt.% PTFE
& different carbon blacks
- coated on commercial
Freudenberg GDL substrate
perfo
ratio
n o
f MP
Ls
perforation of MPLs via a thermally
decomposable pore forming polymer:
dmean = 30 µm (order of dMPL)
10 20 30 40 50 60 70 800
5
10
15
20
25
30
qvo
l. [
%]
dparticle
[µm]
page 20 11/15/2017 Hubert Gasteiger | Chair of Technical Electrochemistry | Technical University of Munich
ε = 79%
dpore = 67 nm
ε = 68%
dpore = 328 nm
dpore = 64 nm
Commercial
Freudenberg Commercial
Freudenberg
Li100 Li100
Li400 Li400
MPL Morphology
change MPL structure (t30mm) by: - carbon black (Li100 & Li400) smooth layers
- perforation large pores/cracks
effect on oxygen and water transport ?
page 21 11/15/2017 Hubert Gasteiger | Chair of Technical Electrochemistry | Technical University of Munich
from: Simon, Kartouzian, Müller, Wilhelm, Gasteiger, J. Electrochem. Soc., in press
H2/Air Performance – MPL Structure Effect
differential-flow H2/air performance with 0.1/0.4mgPt/cm2 (an/ca) Gore MEA (18mm)
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Tcell
= 50 °C
pabs
= 300 kPa
RH = 120%
Tcell
= 80 °C
pabs
= 170 kPa
RH = 100%
Tcell
= 80 °C
pabs
= 170 kPa
RH = 70%
Ec
ell [
V]
0.02
0.04
0.06
HF
R [
W c
m²]
no MPL commercial MPL Li100 Li100 perforated Li400 Li400 perforated
0.02
0.04
0.06
b) c)
0.02
0.04
0.06
0 1 2 3 40.0
0.5
1.0
RT
,O2
[s
cm
-1]
i(lim)
[A cm-2]
0 1 2 3 40.0
0.5
1.0
i(lim)
[A cm-2]
0 1 2 3 41.5
2.0
2.5
3.0
i(lim)
[A cm-2]
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Tcell
= 50 °C
pabs
= 300 kPa
RH = 120%
Tcell
= 80 °C
pabs
= 170 kPa
RH = 100%
Tcell
= 80 °C
pabs
= 170 kPa
RH = 70%
Ec
ell [
V]
0.02
0.04
0.06H
FR
[W
cm
²]
no MPL commercial MPL Li100 Li100 perforated Li400 Li400 perforated
0.02
0.04
0.06
b) c)
0.02
0.04
0.06
0 1 2 3 40.0
0.5
1.0
RT
,O2
[s
cm
-1]
i(lim)
[A cm-2]
0 1 2 3 40.0
0.5
1.0
i(lim)
[A cm-2]
0 1 2 3 41.5
2.0
2.5
3.0
i(lim)
[A cm-2]
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Tcell
= 50 °C
pabs
= 300 kPa
RH = 120%
Tcell
= 80 °C
pabs
= 170 kPa
RH = 100%
Tcell
= 80 °C
pabs
= 170 kPa
RH = 70%
Ec
ell [
V]
0.02
0.04
0.06
HF
R [
W c
m²]
no MPL commercial MPL Li100 Li100 perforated Li400 Li400 perforated
0.02
0.04
0.06
b) c)
0.02
0.04
0.06
0 1 2 3 40.0
0.5
1.0
RT
,O2
[s c
m-1]
i(lim)
[A cm-2]
0 1 2 3 40.0
0.5
1.0
i(lim)
[A cm-2]
0 1 2 3 41.5
2.0
2.5
3.0
i(lim)
[A cm-2]
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Tcell
= 50 °C
pabs
= 300 kPa
RH = 120%
Tcell
= 80 °C
pabs
= 170 kPa
RH = 100%
Tcell
= 80 °C
pabs
= 170 kPa
RH = 70%
Ec
ell [
V]
0.02
0.04
0.06
HF
R [
W c
m²]
no MPL commercial MPL Li100 Li100 perforated Li400 Li400 perforated
0.02
0.04
0.06
b) c)
0.02
0.04
0.06
0 1 2 3 40.0
0.5
1.0
RT
,O2
[s
cm
-1]
i(lim)
[A cm-2]
0 1 2 3 40.0
0.5
1.0
i(lim)
[A cm-2]
0 1 2 3 41.5
2.0
2.5
3.0
i(lim)
[A cm-2]
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Tcell
= 50 °C
pabs
= 300 kPa
RH = 120%
Tcell
= 80 °C
pabs
= 170 kPa
RH = 100%
Tcell
= 80 °C
pabs
= 170 kPa
RH = 70%
Ec
ell [
V]
0.02
0.04
0.06
HF
R [
W c
m²]
no MPL commercial MPL Li100 Li100 perforated Li400 Li400 perforated
0.02
0.04
0.06
b) c)
0.02
0.04
0.06
0 1 2 3 40.0
0.5
1.0
RT
,O2
[s
cm
-1]
i(lim)
[A cm-2]
0 1 2 3 40.0
0.5
1.0
i(lim)
[A cm-2]
0 1 2 3 41.5
2.0
2.5
3.0
i(lim)
[A cm-2]
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Tcell
= 50 °C
pabs
= 300 kPa
RH = 120%
Tcell
= 80 °C
pabs
= 170 kPa
RH = 100%
Tcell
= 80 °C
pabs
= 170 kPa
RH = 70%
Ec
ell [
V]
0.02
0.04
0.06
HF
R [
W c
m²]
no MPL commercial MPL Li100 Li100 perforated Li400 Li400 perforated
0.02
0.04
0.06
b) c)
0.02
0.04
0.06
0 1 2 3 40.0
0.5
1.0
RT
,O2
[s
cm
-1]
i(lim)
[A cm-2]
0 1 2 3 40.0
0.5
1.0
i(lim)
[A cm-2]
0 1 2 3 41.5
2.0
2.5
3.0
i(lim)
[A cm-2]
at 50C / 300kPaa (wet cond.):
Li400 w. larger 2ndary pores
better than Li100 (Hg poros.)
MPLs with cracks superior
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Tcell
= 50 °C
pabs
= 300 kPa
RH = 120%
Tcell
= 80 °C
pabs
= 170 kPa
RH = 100%
Tcell
= 80 °C
pabs
= 170 kPa
RH = 70%
Ec
ell [
V]
0.02
0.04
0.06
HF
R [
W c
m²]
no MPL commercial MPL Li100 Li100 perforated Li400 Li400 perforated
0.02
0.04
0.06
b) c)
0.02
0.04
0.06
0 1 2 3 40.0
0.5
1.0
RT
,O2
[s c
m-1]
i(lim)
[A cm-2]
0 1 2 3 40.0
0.5
1.0
i(lim)
[A cm-2]
0 1 2 3 41.5
2.0
2.5
3.0
i(lim)
[A cm-2]
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Tcell
= 50 °C
pabs
= 300 kPa
RH = 120%
Tcell
= 80 °C
pabs
= 170 kPa
RH = 100%
Tcell
= 80 °C
pabs
= 170 kPa
RH = 70%
Ec
ell [
V]
0.02
0.04
0.06
HF
R [
W c
m²]
no MPL commercial MPL Li100 Li100 perforated Li400 Li400 perforated
0.02
0.04
0.06
b) c)
0.02
0.04
0.06
0 1 2 3 40.0
0.5
1.0
RT
,O2
[s c
m-1]
i(lim)
[A cm-2]
0 1 2 3 40.0
0.5
1.0
i(lim)
[A cm-2]
0 1 2 3 41.5
2.0
2.5
3.0
i(lim)
[A cm-2]
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Tcell
= 50 °C
pabs
= 300 kPa
RH = 120%
Tcell
= 80 °C
pabs
= 170 kPa
RH = 100%
Tcell
= 80 °C
pabs
= 170 kPa
RH = 70%
Ec
ell [
V]
0.02
0.04
0.06
HF
R [
W c
m²]
no MPL commercial MPL Li100 Li100 perforated Li400 Li400 perforated
0.02
0.04
0.06
b) c)
0.02
0.04
0.06
0 1 2 3 40.0
0.5
1.0
RT
,O2
[s c
m-1]
i(lim)
[A cm-2]
0 1 2 3 40.0
0.5
1.0
i(lim)
[A cm-2]
0 1 2 3 41.5
2.0
2.5
3.0
i(lim)
[A cm-2]
at 80C / 170kPaa (std. cond.):
minor differences
suggests tx of H2Oliquid via cracks and O2 via fine pores
MPL design relevant at potential FC operating conditions ?
Ca
tho
de
Su
bstr
ate
MP
L
O2
page 22 11/15/2017 Hubert Gasteiger | Chair of Technical Electrochemistry | Technical University of Munich
from: Simon, Kartouzian, Müller, Wilhelm, Gasteiger, J. Electrochem. Soc., in press
0.0
0.2
0.4
0.6
0.8
1.0
0 1 2 3 4 5 60.0
0.5
1.0
1.5
0.02
0.04
0.06
Ecell [
V]
GDL substrate with
commercial MPL (H14C10)
Li400 MPL
Li400 perforated MPL
RT
,O2
[s
cm
-1]
i(lim)
[A cm-2]
HF
R [
W c
m2]
H2/Air Performance at High Pressure
differential-flow H2/air performance with 0.1/0.4mgPt/cm2 (an/ca) Gore MEA (18mm)
P = 300 kPaa
80°C / 100%RH
optimized MPL shows improved performance
1.5-fold (from 1.3 to 1.9 W/cm2)
page 23 11/15/2017 Hubert Gasteiger | Chair of Technical Electrochemistry | Technical University of Munich
from: Simon, Kartouzian, Müller, Wilhelm, Gasteiger, J. Electrochem. Soc., in press
page 24 11/15/2017 Hubert Gasteiger | Chair of Technical Electrochemistry | Technical University of Munich
H2/air at 100 kPaa
and 80C/100% RH
0.05 mgPt/cm2cathode
effect of catalyst morphology on Pt mass activity and H2/air performance
poor high-i performance of burried Pt lower ORR poisoning by burried Pt
from: Y.-C. Park, H. Tokiwa, K. Kakinuma, M. Watanabe, M. Uchida, J. Power Sources 315 (2016) 179
controlled by
carbon morphology*)
carbon-support vs. Pt deposition method ?
PEM fuel cell materials / structures
Pt reduction strategies:
- Pt needs for the HOR
- ORR catalyst status / limitations
- mass-tx loss phenomena
- MPL/DM design for high-i
- effect of catalyst morphology
Summary
page 25 11/15/2017 Hubert Gasteiger | Chair of Technical Electrochemistry | Technical University of Munich
slides removed (unpublished data)
Summary
<0.1 gPt/kW target can be met by improved catalysts & design for high-i
catalyst morphology is critical
MPL/GDL-substrate design critical for high-i performance
h unaccounted affected by H2Oliquid saturation
Technical Electrochemistry Group !
Thanks to the
page 26 11/15/2017 Hubert Gasteiger | Chair of Technical Electrochemistry | Technical University of Munich