Oxygen reduction at ``electrocoated`` Nafion-modified Ni-carbon composite electrodes in alkaline solution: The effect of temperature

Book · Sat Dec 31 04:00:00 EST 1994

OSTI ID:43068

Swain, G M; Tatarchuk, B J ^[1]

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1. Auburn Univ., AL (United States)

The development of high surface area, high conductivity Ni-Carbon composite electrode structures for use in the oxygen reduction reaction (ORR) in alkaline solution is described. The improvement in the ORR kinetics at composite electrodes modified with electrocoated Nafion membranes and low Pt catalyst loadings was examined as a function of temperature. The electrocoated Nafion membranes appear to possess a higher degree of interfacial contact with the electrode surface and contain less defects than do conventionally dip coated films. The electrocoating procedure may offer a way to more uniformly coat high surface area, 3-D, electrode structures. The results presented indicate that the composite electrodes prepared with nickel overlayers (12 {mu}m diam. fibers), which possess high void volume, and lower Nafion loadings are not structurally stable during extensive potential cycling and gas evolution due to significant carbon loss. More structurally stable electrodes were prepared using nickel overlayers (4 {mu}m diam. fibers), with lower void volume, and higher Nafion loadings. The higher Nafion loadings, while assisting in the carbon retention also result in increased mass transport resistance. In addition, it was observed that the interior of the composite electrode was not uniformly coated with the polymer when using the smaller nickel fiber overlayer. The electrochemical studies of the structurally stable composite electrodes modified with Nafion and low Pt loadings indicate that the electrodes are useful catalyst supports providing intimate contact between the catalyst particles and the interfacial reaction zone.

• OSTI ID: 43068
• Report Number(s): CONF-931024--; ISBN 1-56677-033-5
• Country of Publication: United States
• Language: English

Related Subjects

25 ENERGY STORAGE
ACTIVATED CARBON
CAPACITORS
CARBON FIBERS
COMPOSITE MATERIALS
ELECTRIC BATTERIES
ELECTRIC CONDUCTIVITY
ELECTROCHEMISTRY
ELECTRODEPOSITED COATINGS
ELECTRODES
EXPERIMENTAL DATA
FABRICATION
FUEL CELLS
NICKEL
ORGANIC POLYMERS
PERFORMANCE
PLATINUM
REDOX REACTIONS
TEMPERATURE DEPENDENCE