Progress in HT-PEM fuel cells

F-Cell, Stuttgart 30th Sep. 2013

Hans Aage Hjuler and Thomas Steenberg

Danish Power Systems

®

Outline

The two Danish test windmills from 1891 and 1897, incl. electrolysis, H2

storage and H2 light.

• Introduction

• MEA performance

• Durability

• Summary

About DPS

“DPS produce and develop the energy efficient HTPEM

technology which utilizes renewable fuels. This is to the benefit of

our customers, society, public health and the environment”

• DPS is an independent and privately owned company.

• DPS was founded in 1994.

• Since 2010 DPS has focused on the actual single fuel cell unit (MEA).

• Strong network with international and Danish companies, universities

and organizations.

• Member of the Danish Partnership for Hydrogen and Fuel Cells.

3

High Temperature PEM FC

4

N

N

N

Nn

HH

Poly (2,2´-m-(phenylene)-5,5´-bibenzimidazole)

Well-known temperature resistant polymer

Tg = ~430ºC

When doped with phosphoric acid:

Proton conductor

Wainright and Savinell. J. Electrochem. Soc. 142 (1995) L121

DPS’ capabilities - MEA manufacturing

Electrode spray

5

Polymer synthesis Membrane casting

Assembly and QC

Standard Products:

• Dapozol® membranes:

o M20 – 20 my membranes

o M40 – 40 my membranes

o M60 – 60 my membranes

o M80 – 80 my membranes

• Dapozol® MEAs:

o G33 – 3 x 3 cm active area

o G55 – 5 x 5 cm active area

o G77 – 7 x 7 cm active area

o G717 – 7 x 17 cm active area

o G1018 – 10 x 18 cm active area

HT-PEM Technology

8

The HTPEM technology has a number of very

attractive features – fuel flexibility is a very

significant advantages.

Typical operating temperature: 140-180 °C.

It can work with hydrogen but also reformat (from

e.g. natural gas, methanol and LPG).

Features:

Reformate or H2

High CO tolerance

No need for humidification

High value of excess heat

=> System simplicity

Reformer Fuel cell

Electricity

Nat. Gas,

Methanol

H2

CO2

CO

CO clean-up

to 0,001 %

H2

CO2

Heat

Air in Air out

Humidification

of the air

Simple HTPEM system

9

Polarization - hydrogen and reformate

10

Polarization curve for MEAs tested with hydrogen and reformate (2.3% CO) at 160 °C.

HT-PEM MEA technology:

11

Performance

Cost Durability

Pt loading

MEA design

Pt loading

MEA design

Pt loading

Membrane (T, DL)

Temperature

MEA – losses: 12

Contact resistance

Anode resistance

+ η

Membrane resistance

Cathode losses

+ ηORR

MEA performance:

13

165 cm2 MEA

160 °C

CD = 200 mA/cm2

λH2/λair = 1.5 / 2.5

Reference MEA performance using JM catalyst:

MEA characterization

400

500

600

700

800

900

1000

1100

1200

1300

10 100 1000

EIR

-fre

e (

mV

)

i (mA/cm²)

RD-13-147 after 16h

equilibrium

iR free O2

iR- free air

Pure O2 equilibrium potential

Performance loss at 1A/cm²

due to cathode kinetic loss

Performance loss at 1A/cm² due

to cathode mass transport loss

MEA performance analysis:

15

1.5 mg Pt/cm2 on cathode

25 cm2 MEA

MEA performance analysis:

16

Temperature dependence: 17

MEA performance analysis – PTFE binder:

18

0.9 mg Pt/cm2 on cathode

25 cm2 MEA

MEA performance analysis – PTFE binder:

19

After 90 h break-in at 200

mA/cm2

MEA performance analysis – PTFE vs. PBI:

20

PTFE: Potential better kinetics but still some mass transport issues…

=> A potential path to reduced Pt loading.

MEA - Catalyst comparison :

21

25 cm2 MEA

160 °C

λH2/λair = 1.5 / 2.5

Different carbon substrates!

Best performance yet:

22

Polarization curves at 160 °C

49 cm2 MEA. The Pt loading on the cathode 1.5 mg Pt/cm2

The MEA’s was measured by Aalborg University.

Durability testing (on-going):

23

160 °C

240 mA/cm2

9 cm2 active area

λH2 = 7

λair = 12

ΔV = 9 μV/h (avg)

DPS technology status:

• PBI synthesis (uniform Mw)

• PBI membranes (standard and x-linked membranes)

• MEA’s (standard and custom sizes)

• Performance and durability

• Commercial production

• Further up-scaling

24

Collaboration!

25

Summary & perspectives:

• HTPEM has a large potential in a number of applications due to system

simplicity and fuel flexibility

• Performance and durability test shows that operating conditions are

important for fuel cell performance and life time

• MEA performance has been significantly improved

• Scale-up of MEA production is in progress

26

Acknowledgements

EUDP, the Danish Ministry of Energy

Energinet.dk, the Danish Electrical Utilities

Danish Agency for Science, Technology and Innovation

Danish National Advanced Technology Foundation

DTU Energy Conversion, Technical University of Denmark

27

Our team

28

Thank you for your attention

www.daposy.com