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October 8, 2014 Copyright 2014 Pajarito Powder, LLC 1
Precious Metal Free Fuel Cell Catalysts, Concepts and Limits
Barr Halevi, Pajarito Powder LLC
World of Energy Solutions
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 2
Outline
• What are non‐PGM ORR catalysts?• Identifying the active site/s and mechanism• Key morphology• Making deployable non‐PGM catalysts• Successes• Challenges
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 3
PPC Introduction
PPC founded to:Create & ManufactureAffordable Fuel Cell
Catalystsin Commercial Quantities
Piotr Zelenay
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 4
PPC Introduction
PPC founded to:Create & ManufactureAffordable Fuel Cell
Catalystsin Commercial Quantities
Mix PrecursorsBall‐Mill
Precrusor storagePrecursor vacuum drying
Pyrolysis Furnace 1
HF storageSlurry mixingFilter
Waste container
Atmospheric OvenPyrolysis Furnace 2
Weighing
Di storage
Milled mix storage
P1, boat, dateLabe; sits on shelf in jar
Pyrolyzed storage
Labe; sits on shelf in jar
Etched storage
Labeled, sits on shelf in jar
2‐4 P2s
Testing:BET
ConductivityCharringMEA
P2 storage
Decide P2, P1, and etching
Packaging ShippingQuality Assurance
Ball‐Mill
HNO3 storage
1.5gr
50gr10gr
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 0.5 1 1.5I (A/cm2)
E (V
olts
, unc
orre
cted
)
Interbatch 1Intrabatch 2AIntrabatch 2BIntrabatch 2CInterbatch 3 (100kg Precursor batch)
Testing conditions0.5bar O2 100%RH 80
oC 211 membrane, 45wt% Nafion 1100Anode = 0.2mgPt/cm
2
Cathode = 2.3mgcat/cm2
US20080312073A1,WO2012174335A2,WO2013116754A1,WO2012174344A2,WO2014062639A1,WO2014011831A1,WO2014085563A1,WO2014113525A1,
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 5
Non‐PGM Catalysts
Polypyrrole
Polyaniline
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 6
Outline
• What are non‐PGM ORR catalysts?• Identifying the active site/s and mechanism
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 7
Active Site Identification
• Electrochemical Analysis– Rotating Ring and Rotating Disk Electrode (RRDE and RDE)
• Ab‐initio calculations ‐ Density Functional Theory (DFT)• Multiple chemical species & Activity correlation
– X‐Ray Photoelectron Spectroscopy (XPS)– Aberration Corrected Transmission Electron Microscopy (ACTEM)
– Raman Spectroscopy– Mössbauer Spectroscopy – X‐Ray Absorption Spectroscopy (XAS)
– Electrochemical XAS (e‐XAS)• Good statistical analysis and correlation of all of the above!
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 8
H2O
T.S. Olson, S. Pylypenko, J.E. Fulghum, P. Atanassov, Journal of the Electrochemical Society, 157 (2010) B54-B63
Oxygen Reduction Reaction on Non-PGM Catalysts
• Bi(+?) -functional Mechanism• Two(+?) types of Active Sites
Multifunctional Site/s
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 9
Density-Functional-Theory (DFT).• Generalized Gradient Approximation (PBE).• 3-d periodic boundary conditions.• Plane-waves.• Spin polarized: Co. • PAW-potentials.• Fermi-smearing (σ=0.025 eV)
Boris Kiefer
Surfaces: • Graphene (32 atoms). • 14 A vacuum.• Molecule(s) pre-optimized.• Dipol correction.
DFT: Fe(N‐C)4 Most Likely
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 10
DFT: Fe(N‐C)4 Most Likely
Possible electron arrangements in 3d orbitals of Fe+2 in Fe-N4 sites: a) high spin, b) intermediate spin, and c) low spin states, and d) electronic density of states (DOS) of Fe in graphitic Fe-N4 sites S. Kattel, P. Atanassov and B. Kiefer, PCCP 13800-13806
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 11
3963984004024041500
2000
2500
3000
nitrile
pyridinic
Nx-Fepyrrolic
quaternary
graphitic
Binding energy, eV
cps
7067087107127147167187202600
2700
2800
2900
3000
3100
Fe-Nx
Fe
Fe oxides
satellites
Binding energy, eVcp
s
a)
XPS: Fe(N‐C)x Exist
Kateryna Artyushkova
b)
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 12
DFT calculations of XPS binding energy shifts
Both Me-N2 and Me-N4centers are present but their relative amount changes upon exposure to oxidizing atmosphere –stabilization of N4 centers
Vacuum
3963984004024044063200
3400
3600
3800
4000
4200
Binding energy, eVcp
s
O2, 60oCPolypyridine
Bipyridine-Fe
N- pyridinic
N- pyridinic
N-Fe
Ambient pressure XPS
K. Artyushkova, B. Kiefer, B. Halevi, A. Knop-Gericke, R. Schlogl and P. Atanassov, Chem. Comm, 49 (2013) 2539 – 2541
Me‐N4 Me‐N2 Me‐N2
theory +1.1 eV 0.8 eV 1.0 eV
experiment +0.9‐1.1 eV
XPS & DFT: Matching
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 13
Gerd Duscher Matt Chisholm
ACTEM images proves Nitrogen & Iron single sites in graphene
ACTEM – Fe/N Sites Exist
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 14
The relative content of D1 or D2 is high, demonstrating the successful integration of the majority of the iron in FeNxCymolecular sites during pyrolysis.
The existence of Fe-N coordinations by Mössbauer spectra, (doublets) is also supported by the Fe-N binding energy in XPS at 399.6 eV. Pyridinic &
disorderedFe-Nx
Fe-Nx
Frederic Jaouen, U Montpellier
Mössbauer: Fe(N‐C)4
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 15
Sanjeev Mukerjee
Fe2+-N4 active site at 0.3 V undergoes redoxtransition to a penta-coordinated (H)O−Fe3+−N4 at 0.90 V
XAS – Fe(N‐C)x & Fe‐Fe
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 16
U. Tylus, Q. Jia, K. Strickland, N. Ramaswamy, A. Serov, P. Atanassovand S. Mukerjee, J. Phys. Chem. C, 118 (2014) 8999-9008
eXAS – mechanism?
Oxygen Reduction Reaction on Non-PGM Catalysts• Bi(+?) -functional Mechanism• Two(+?) types of Active Sites
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 17
Outline
• What are non‐PGM ORR catalysts?• Identifying the active site/s and mechanism• Key morphology
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 18
Pore Structures
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 19
Pore Structure Role
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 20Kateryna Artyushkova
Structure-to-Property Relationships
E 1/2
N 1s %
N cyano
N pyridinic
N-Fe N pyrrolic
N quaternary
N graphitic
PC1 53.6%
PC2 20.0%
Worse performance
Best performance
Polymers Low MW organics Chelates
Different Active Sites
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 21
Outline
• What are non‐PGM ORR catalysts?• Identifying the active site/s and mechanism• Key morphology• Making non‐PGM catalysts
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 22
Making Non‐PGM Catalysts
• Multiple ways to make non‐PGM catalysts– Need to bring precursors together on nano‐scale then react them to make active sites
– Some processes are very complex with iterations of mixing, cooking, pyrolysis, etching.
– Commonality:• Similar precursors
– M/N/C compounds (ex: cyanamide) & Metal salts +N/C compounds• Mixing• Pyrolysis at 800‐950C• Etch excess metal particles
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 23
edge defectsedge defects
in-plane defectsin-plane defects
Different Active Sites
• Edge less stable, more active• In-plane more stable, less active• Need in-plane for stable/durable catalysts!
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 24
Sacrificial Support Method
Template: monodispersedamorphous silica
infused with transition metal saltand N-C precursor
pyrolyzedin inert atmosphere
silicaetched by HFand removed
Fumed Silica: BET-SA ~50-400 m2/g
N-C Precursor:1,4-Phenylenediamine3-Hydroxytyramine 4-Aminoantipyrine DiethanolamineN-HydroxysuccinimidePhenanthrolineCarbendazime
TemplatedSelf-supported
Non-PGM CatalystMetals: Ce, Zr, V, Ti, Ta, Nb, W, Mo, Fe, Ru, Co, Ni, Cu
Alexey Serov
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 25Ball‐Mill Pyrolysis Etching Centrifuge Filter Dry Pyrolysis
SSM Catalyst Evolution
Silica Infused with precursors
Pyrolizedinfused silica
Etched pore structure
Porous non-PGM catalyst
Pore structure evolution
Pyrolizedpore structure
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 26
Precipitated Silica:Sponge-like
Fumed Silica:Sponge-like
ECS PEFC SHORT COURSE 2013, SFO (T.J. Schmidt & H.A. Gasteiger)
Typical Pt/C
Primary particle size:10-40nm
Sacrificial support allows for pore sizetailoring to match current Pt/C catalystsSacrificial support allows for pore size
tailoring to match current Pt/C catalysts
EvonikAerosil
SSM Pore Structure
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 27
0
100
200
300
400
500
0
0.2
0.4
0.6
0.8
1
0 0.5 1 1.5 2
HFR
(mΩ
-cm
2 )
Cel
l Vol
tage
(V)
Current Density (A/cm2)
55% Nafion
45% Nafion
35% Nafion
~ 0.92 V OCV Catalyst loading is 4 mgcatalyst/cm2
0.60
0.70
0.80
0.90
0.001 0.01 0.1 1
IR-fr
ee C
ell V
olta
ge (V
)
iR-free Current Density (A/cm2)
55% Nafion
45% Nafion
35% Nafion
Conditions: Tcell=80C, 100% RH 1.5 bar total pressure. Anode: 0.4 mg cm-2 (Pt/C),Cathode: 4mg cm-2
Meets DoE target of 100 mA/cm2 at 0.8ViR-free in Oxygen
Iron Nicarbazin Catalyst
Fe +
DOE EERE Project ID# FC086 AMR 2103 report, NTCNA testing
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 28
DOE EERE Project ID# FC086 AMR 2103 report, NTCNA testing
0
100
200
300
400
500
0
0.2
0.4
0.6
0.8
1
0 0.5 1 1.5 2
HFR
(mΩ
-cm
2 )
Cel
l Vol
tage
(V)
Current Density (A/cm2)
Beginning of Life (BoL)End of Life (EoL)
Conditions: Tcell=80C, 100% RH 1.5 bar total pressure. Anode: 0.4 mg cm-2 (Pt/C),Cathode: 4mg cm-2.
Load cycling AST – Good!
Minimal change in performance is observed after 10,000 potentialcycles (load cycling) from 0.6 to 1.0V.
Minimal change in performance is observed after 10,000 potentialcycles (load cycling) from 0.6 to 1.0V.
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 29
-30
-20
-10
0
10
20
30
0 0.2 0.4 0.6 0.8 1
Curr
ent D
ensi
ty (m
A/cm
2 )
Potential (V)
after 0 cycles
after 50 cycles
after 100 cycles
after 200 cycles
after 500 cycles
after 1000 cycles
Start/Stop AST – Good!
DOE EERE Project ID# FC086 AMR 2103 report, NTCNA testing
EXAFS
ECSA
Durability under start/stop similar to Pt/CDurability under start/stop similar to Pt/C
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 30
Volumetric Projection
Volumetric Projections
Volumetric Current (A/cm3)
0.01 0.1 1 10 100 1000
Volta
ge (V
), iR
-free
0.70
0.75
0.80
0.85
0.90
0.95
MEA 2MEA 10MEA 14
Sanjeev Mukerjee, NEU
Sample mV @ 200 A/cm3
A/cm3 @ 0.8 V (iR free)
MEA 2 809 400MEA 10 796 150MEA 14 810 400
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 31
Outline
• What are non‐PGM ORR catalysts?• Identifying the active site/s and mechanism• Key morphology• Making deployable non‐PGM catalysts
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 32
100mL
500mL
1L
1”x 6”
6”x 30”
2000mL
500mL
15mL 50mL
0.5L
20L
Batch Size
0.5 g
50 g
100 g
Scale‐up process
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 33
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 0.5 1 1.5I (A/cm2)
E (V
olts
, unc
orre
cted
)
Interbatch 1Interbatch 2Intrabatch 3AIntrabatch 3BIntrabatch 3CInterbatch 4 (100kg Precursor batch)
Testing conditions0.5bar O2 100%RH 80
oC 211 membrane, 45wt% Nafion 1100Anode = 0.2mgPt/cm
2
Cathode = 2.3mgcat/cm2
Improved inter-batch variability illustrated by Samples 1, 2, 3 and 4 Improved intra-batch variability (
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 34
Proprietary
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 0.2 0.4 0.6 0.8 1I (A/cm 2)
E(V
olts
, iR
unco
rrect
ed)
Gen1Gen1AGen1BGen2Gen2AGen2BTargets
211 Nafion, 45wt% 1100 EW, 4mg/cm 2
catalyst, 25BC GDL, 100% RH, 2.5bar AirI
II
Improved formulation
Catalyst formulation leading to MEA performance improvementsDoE Target I met, without iR correction – 60% improvement towards target II
Catalyst formulation leading to MEA performance improvementsDoE Target I met, without iR correction – 60% improvement towards target II
US20080312073A1,WO2012174335A2,WO2013116754A1,WO2012174344A2,WO2014062639A1,WO2014011831A1,WO2014085563A1,WO2014113525A1,
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 35
Proprietary0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0.01 0.1 1I (A/cm2)
E(V
olts
, iR
unco
rrect
ed)
Gen1Gen1AGen1BGen2Gen2AGen2BTargets
211 Nafion, 45wt% 1100 EW, 4mg/cm 2 catalyst, 25BC GDL, 100% RH, 2.5bar Air
I
II
Improved formulation
Catalyst formulation leading to MEA performance improvementsDoE Target I met, without iR correction – 60% improvement towards target II
Catalyst formulation leading to MEA performance improvementsDoE Target I met, without iR correction – 60% improvement towards target II
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 36
Outline
• What are non‐PGM ORR catalysts?• Identifying the active site/s and mechanism• Key morphology• Making deployable non‐PGM catalysts• Successes
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 37
Non‐PGM ORR catalysts
• Characterization techniques developed• Mostly likely active site/s identified• Iterative approach to synthesis
– Key factors hypothesized– Catalysts made– Catalysts characterized
• Correct surface chemistry • Porosity
– Key factors identified37
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 38
Commercialization
38
43rd Tokyo Motor Show
Precious Metal Free Fuel Cell Electric Vehicle
20132013A. Serov, M. Padilla, A.J. Roy, P. Atanassov, T. Sakamoto, K. Angewandte Chemie Intern. Ed., (2014) DOI: 10.1002/anie.201404734
B. Pivovar, Alkaline Membrane Fuel Cell Workshop Final Report
NREL/BK-5600-54297
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 39
PPC Capabilities
• Multiple no‐PGM catalyst production methods and formulations scaled to 25‐100gr
• Fixed Product Line (200gr/day capacity)– NPC‐2000 & 1000: non‐platinum, drop‐in fuel cell catalysts with different performance/price points
– PHC‐3000: Ultra low loaded platinum content catalyst for higher performance
• Custom Catalyst Design• Contract Manufacturing
39
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 40
Outline
• What are non‐PGM ORR catalysts?• Identifying the active site/s and mechanism• Key morphology• Making deployable non‐PGM catalysts• Successes• Challenges and Limits
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 41
Limits
• Pt/C activity per gram likely unachievable• BUT, Cost/Performance parity exists today
– $/kW to improve dramatically at scale
• Additional work is needed– Electrode must be re‐optimized for non‐PGM– Additional durability and stability testing
41
$‐$40$80
10 1,000 100,000Monthly Production (Kg)
Price/kW
($USD
) NPC‐2000 Pt Catalyst
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 42
Thanks
• Verge Fund• US Department of Energy, Energy Efficiency and
Renewable Energy Program• University of New Mexico
• Profs. Plamen Atanassov, Alexey Serov, and Kateryna Artyushkova• New Mexico State University
• Prof. Boris Kiefer• Northeastern University
• Prof. Sanjeev Mukerjee and several students• Michigan State University
• Prof. Scott Calabrese Barton and Nate Leonard• Los Alamos National Laboratory
• Drs. Piotr Zelenay, Hoon Chung, and Gang Wu• Nissan technical Center North America
• Drs. Nilesh Dale, Ellazar Niangar, and Taehee Han
October 8, 2014 Copyright 2014 Pajarito Powder, LLC 43
Questions?
Barr Halevi, CTO & President ([email protected])
Pajarito Powder, LLC317 Commercial St. NE
Albuquerque, NM 87102, USA+1 (505) 293‐5367
www.pajaritopowder.com