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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


Outline

• What are non‐PGM ORR catalysts?• Identifying the active site/s and mechanism• Key morphology• Making deployable non‐PGM catalysts• Successes• Challenges


PPC Introduction

PPC founded to:Create & ManufactureAffordable Fuel Cell

Catalystsin Commercial Quantities

Piotr Zelenay


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,


Non‐PGM Catalysts

Polypyrrole

Polyaniline


Outline

• What are non‐PGM ORR catalysts?• Identifying the active site/s and mechanism


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!


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


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


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


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)


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


Gerd Duscher Matt Chisholm

ACTEM images proves Nitrogen & Iron single sites in graphene

ACTEM – Fe/N Sites Exist


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


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


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


Outline

• What are non‐PGM ORR catalysts?• Identifying the active site/s and mechanism• Key morphology


Pore Structures


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


Outline

• What are non‐PGM ORR catalysts?• Identifying the active site/s and mechanism• Key morphology• Making non‐PGM catalysts


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


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!


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


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


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



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.


-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!


EXAFS

ECSA

Durability under start/stop similar to Pt/CDurability under start/stop similar to Pt/C


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


Outline

• What are non‐PGM ORR catalysts?• Identifying the active site/s and mechanism• Key morphology• Making deployable non‐PGM catalysts


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


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 (


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


US20080312073A1,WO2012174335A2,WO2013116754A1,WO2012174344A2,WO2014062639A1,WO2014011831A1,WO2014085563A1,WO2014113525A1,


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




Outline

• What are non‐PGM ORR catalysts?• Identifying the active site/s and mechanism• Key morphology• Making deployable non‐PGM catalysts• Successes


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


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


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


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


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


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


Questions?

Barr Halevi, CTO & President ([email protected])

Pajarito Powder, LLC317 Commercial St. NE

Albuquerque, NM 87102, USA+1 (505) 293‐5367

www.pajaritopowder.com

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