Air Electrode in Hydrogen Fuel Cell

Physics REU 2012

Diana Gutierrez ZedanoMentors: Dr. Flanders & Dr. Sorenson

Hydrogen Fuel Cell

H2 2H+ + 2e-

O2 in air

cathodeanode

H2 source

O2 + 4e- 2O2-

H+ O2- 2H+ + O2- H2O

Air electrodeexternal circuit

electrolyte varies

reduction

green waste

Cross Sectional View of the Air Electrode

Bjorn Winther-Jensen et all. High Rates of Oxygen Reduction over a Vapor Phase–Polymerized PEDOT Electrode. Science. August 2008: 671-674

Gore-tex Gold PEDOT

Carbon Aerosol Gel

Gore-tex Fabric

Hydrophobic - keeps electrolyte from going through the pores

Porous - “breathable”

Academy of Art University of San Francisco

Carbon Aerosol Gel

Acetylene or ethylene with oxygen are kept in a fuel rich chamber and ignited by a spark. This produces an incomplete combustion which allows for the aggregation of carbon particles

Pores confined within fractal structure

Black color (like PEDOT): use Raman spectrum to differentiate Bands: D 1330, G 1580, G’ 2646

Raman Spectrum for Carbon Aerosol Gel

Wavenumber (cm-1)

1000 1500 2000 2500 3000

Inte

nsit

y (a

u)

-5

0

5

10

15

20

PEDOT poly(3,4-ethylenedioxythiophene)

Low electrical conductivity: gold layer is needed

O2 reduction catalyst

Wikipedia

Not sensitive to carbon monoxide Raman Spectrum Band: Double carbon bond

Raman Spectrum for PEDOT

Wavenumber (cm-1)

500 1000 1500 2000

Inte

nsit

y (a

u)

-100

0

100

200

300

400

500

600

700

O2 + 4e- 2O2-

Experimental Process Carbon aerosol gel is pressed on Goretex

Resistance varies from 25 to 3 kilo ohms

Electro deposition of gold on carbon-coated Goretex. 20 mM HAuCl4

2 V DC

Electro polymerization of PEDOT film on gold-coated Goretex. 10 mM EDOT and 20 mM PSS 2 V DC

Raman Spectrum for Air Electrode

Wavenumber (cm-1)

1000 1500 2000 2500 3000

Inte

nsit

y (a

u)

0

10

20

30

40

50

60Carbon Aerosol GelGlass Au PEDOTGoretex Carbon Au PEDOT

Testing Air Electrode

Pt Counter Electrode

Working Electrode

Copper tape

Half of the hydrogen fuel cell Electrolyte: 1M H2SO4

H2SO4

O2 + 4e- 2O2-

O2 in air

Air electrode test dataTrial

Applied Voltage (V)

-0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8

-I (

mA

)

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

Goretex-carbon-Au-PEDOTGoretex-Carbon-AuGoretex-CarbonGoretex

Future Plans Air electrode needs to be tested in an oxygen free

environment. Work out a method to enhance the amount of PEDOT

deposition

Acknowledgments

I would like to thank: NSF for funding Dr. Flanders and Dr. Sorenson who guided me through the

project Govind Paneru for teaching me the skills I needed for my project Dr. Flanders, Dr. Sorenson and Arjun Nepal who made the

carbon aerosol gel sample Dr. Weaver and Dr. Corwin for coordinating the program