An Intermediate Temperature

Metal-Supported Proton-Conducting

Solid Oxide Fuel Cell Stack

18th Annual SOFC Workshop

June 14, 2017

Stack Concept

2

Feature Lead Organizations

Proton-Conducting

Oxide

Metal Support

Internal Fuel

Reforming

CH4, H2O CH4, H2O, CO2, CO

Air Air – O2 + H2O

Metal supported p-SOFC with internal CH4 reforming

CHP System Concept & Efficiency

3

Assumptions

Methane Conversion 90%

H2 Utilization 80%

OCV (V/Cell) 1.05

ASR (cm2) 1

Current Density (mA/cm2) 200

Parasitic Power / Stack Power 9%

Inverter Efficiency 95%

Heat Recovery Temp 75 °C

Overall stack

efficiency Net electric

efficiency

Effective

Electric

Efficiency

(57%)

12.8 g/s

35 C

13.4 g/s 0.6 g/s

80 C 35 C

13.4 g/s 12.6 g/s 12.7 g/s 12.7 g/s

246 C 463 C 538 C 385 C

12.6 g/s

15 C

0.6 g/s

463 C

0.7 g/s

13.4 g/s 463 C

598 C

12.7 g/s 0.2 g/s

385 C 15 C

HEX Hot In

Burn In Cath

Cath ExitCath In Boil Out

Anode Out

HEX Hot Out

NG In

Rec. H2O

Steam

HR Exit

Exhaust

Air Inflow Cathode

SR & Anode

PC SOFC Stack

Stack Afterburner

Exhaust Heat RecoveryHeat Exchanger

Fresh Fuel & SteamMixer

Building/Potable Water Heating/Cooling Sub-System

Natural Gas

Exhaust

SystemBlower

Recuperator

Air CooledExhaust

Condenser

Boiler

Recovered Water Pump

PCO-Electrolytes: Exceed Target Conductivity

4

1.0 1.5 2.0 2.5 3.010

-6

10-5

10-4

10-3

10-2

1000/T (K-1)

Co

nd

uctivity (

S/c

m)

comp 1 1.91

comp 2 1.78

comp 3 1.66

comp 4 2.00

target 1.5

, 10-2S/cm

700600 500 400 300 200 100

Temperature (oC)

pH2O = 0.031 atm

Balance N2

Gen-2

Combinatorial Electrode Development

5

Pr concentration

Cathode: BaZrYO3 - BaPrYO3

Typical spectra

Pr-rich, fixed composition

Vary diameter

Observation: strong composition dependence, slight diameter dependence

diameter

BYZ BYP

0 1 2 3 40.0

0.2

0.4

0.6

0.8

1.0

1.2

700 C

650 C

600 C

550 C

500 C

Current Density (A cm-2)

Volta

ge

(V

)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

Po

we

r De

nsity

(w c

m-2)

0 1 2 3 40.0

0.2

0.4

0.6

0.8

1.0

1.2

700 C

650 C

600 C

550 C

500 C

Current Density (A cm-2)

Volta

ge

(V

)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

Po

we

r De

nsity

(w c

m-2)

Anode Supported Button Cell Performance in H2

6

Cell-1 Cell-2

ACIS ohmic , cm2 Non-ohmic , cm2 Peak PD cm-2

T (oC) #1 #2 #1 #2 #1 #2

700 0.179 0.142 0.050 0.056 1.009 1.087

600 0.295 0.213 0.265 0.266 0.516 0.558

500 0.461 0.338 1.420 1.732 0.236 0.255

Cathode sintered at 1000 C

0 100 200 300 400 500 600 7000.0

0.2

0.4

0.6

0.8

1.0

Curr

ent

Density (

A c

m-2

)

Time (h)

@ 0.5 V

Cell Performance Stability Evaluation

7

humidified H2 / cell / air

T = 550 °C

Test period ≈ 700 h

Degradation rate ≈ 0

< 2 10-3 %/h target

0.72 A cm-2

Excellent Stability in CO2

8

Long-term OCV measurement

Anode gas: humidified H2; humidified 90% H2, 10% CO2

Further Performance Improvement Demonstrated

9

0 1 2 3 4 50.0

0.2

0.4

0.6

0.8

1.0

1.2 650

600

550

500

450

Current Density (A cm-2)

Volta

ge

(V

)

0.0

0.4

0.8

1.2

1.6

Pow

er D

ensity

(w c

m-2)

0 1 2 3 4 50.0

0.2

0.4

0.6

0.8

1.0

1.2

650

600

550

500

Current Density (A cm-2)

Voltage (

V)

0.0

0.4

0.8

1.2

1.6

Po

we

r De

nsity

(w c

m-2)

0.1 0.2 0.3

0.00

0.05

0.10

0.15

111118

Without PLD

With PLD

-lm

(Z)

(c

m2)

Re(Z) (cm2)

@ 600 oC

11811 1

Decreased ohmic loss

Without PLD With PLD

Cathode

Cathode PLD layer

Electrolyte

Operation under Methane: 1st Attempt

10

Ohmic ( cm2) Non-ohmic ( cm2) Peak power density

(W cm-2)

650 0.139 0.132 0.548

600 0.197 0.345 0.332

550 0.277 0.992 0.181

500 0.369 2.833 0.094

0.0 0.5 1.0 1.5 2.00.0

0.2

0.4

0.6

0.8

1.0

1.2 650

600

550

500

Current Density (A cm-2)

Volta

ge

(V

)

0.0

0.2

0.4

0.6

0.8

P

ow

er D

ensity

(w c

m-2)

Ru on anode,

28.2%CH4+71.8%H2O

0 10 20 30 40 50 600.0

0.2

0.4

0.6

0.8

1.0

OC

V (

V)

Time (min)

@ 600 °C

Metal Support Design

11

Metal Porous Sheet (substrate for p-SOFC trilayer)

Metal C-Ring Inserts/Orifices (3 out of 4 visible)

Metal Foam (substrate for reforming catalyst)

Metal Stamped Dish

Insulator Couplings (2 out of 4 visible)

(1)

(2)

(3)

(4)

(5)

Subject to the export

restrictions on the title page..

Enabling Fabrication Approach: Reactive Spray Deposition Technology (RSDT)

Cell Manufacturing Process: RSDT

12

Cell Deposition on Metal Support by RSDT

13

• Demonstrated thin dense electrolyte (leak rate ~<0.05 ml/min/cm2 at 1” H2O)

• Challenges in anode deposition on porous metal:

• Adherent layer

• Able to bridge large pores

Electrolyte

Anode Metal Substrate

Anode

Recent Progress Made in RSDT Full Cell Deposition

5 x5 cm2 metal supported cell

Technoeconomic Analysis of 5-kWe System

15

8 major system

components

Key operating conditions:

Stack mean T = 500 °C;

Cell area = 100 cm2

H2 utilization = 80%; CH4

reforming conversion =

90%

ASR

[Ω cm-2]

Stack temp.

[°C]

i

[A cm-2]

Power Density

[W cm-2]

Stack cost

[$/kWe]

System cost

[$/kWe]

1.0 500 0.2 0.17 916 2005

0.5 600 0.2 0.19 764 (-16%) 1323 (-34%)

Summary

Progress

Cell materials

Stack design

RSDT fabrication process

Next Steps

Further improvement of cell deposition

Performance demonstration of metal supported cell

Continue material development

16

Acknowledgements

17

Organization Team Members

Sossina Haile, Sihyuk Choi, Chris

Kucharczyk, Daekwang Lim

John Yamanis

Radenka Maric, Tim Myles, Ryan Ouimet

Ichiro Takeuchi, Xiaohang Zhang, Yangang

Liang

Tianli Zhu, Justin Hawkes, Sean Emerson,

Neal Magdefrau, Xian Tang

Grigorii Soloveichik, Scott Litzelman, John Tuttle,

John Lemmon

The information, data, or work presented herein was funded in part by the Advanced Research Projects

Agency-Energy (ARPA-E), U.S. Department of Energy, under Award Number DE-AR0000498.

Back Up

18

Proton Conducting Oxide

19

High-Throughput Material Evaluation Approach

20 25 30 35 40

Inte

nsity (

a.

u.)

2 Theta

20 40 60 80

after 100% CO2 500

oC/12h

Inte

nsity (

a.

u.)

2 Theta

as-sintered

CO2 stability of Gen-2 Electrolyte

20

BaCO3 BaCO3

0 300 600 900

99

102

105

108

N2

40% CO2 & N

2

Mass (

%)

Time (min.)

N2

0

200

400

600

800

1000

Tem

pera

ture

(oC

)

• No carbonate detected by diffraction

• No weight gain under flowing CO2

800 °C

dehydration

System Concept

21

12.8 g/s

35 C

13.4 g/s 0.6 g/s

80 C 35 C

13.4 g/s 12.6 g/s 12.7 g/s 12.7 g/s

246 C 463 C 538 C 385 C

12.6 g/s

15 C

0.6 g/s

463 C

0.7 g/s

13.4 g/s 463 C

598 C

12.7 g/s 0.2 g/s

385 C 15 C

HEX Hot In

Burn In Cath

Cath ExitCath In Boil Out

Anode Out

HEX Hot Out

NG In

Rec. H2O

Steam

HR Exit

Exhaust

Air Inflow Cathode

SR & Anode

PC SOFC Stack

Stack Afterburner

Exhaust Heat RecoveryHeat Exchanger

Fresh Fuel & SteamMixer

Building/Potable Water Heating/Cooling Sub-System

Natural Gas

Exhaust

SystemBlower

Recuperator

Air CooledExhaust

Condenser

Boiler

Recovered Water Pump

Net DC Power (W)= 5000

Net AC Power / Methane LHV= 51%

Recovered Heat /Methane LHV= 25%

Effective Electric Efficiency= 57%

Performance Summary5 kW Residential CHP System

Better Cathode/Electrolyte Interface via PLD Layer

22

(a) (b) (c)

950 C Sintered without PLD 900 C 1000 C

Sintered at T 950 C with PLD