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Oxygen electrodes for rechargeable alkaline fuel cellsElectrocatalysts and supports for the positive electrode of moderate temperature single-unit rechargeable alkaline fuel cells are being investigated and developed. Candidate support materials were drawn from transition metal carbides, borides, nitrides and oxides which have high conductivity (greater than 1 ohm/cm). Candidate catalyst materials were selected largely from metal oxides of the form ABO sub x (where A = Pb, Cd, Mn, Ti, Zr, La, Sr, Na, and B = Pt, Pd, Ir, Ru, Ni (Co) which were investigated and/or developed for one function only, O2 reduction or O2 evolution. The electrical conductivity requirement for catalysts may be lower, especially if integrated with a higher conductivity support. All candidate materials of acceptable conductivity are subjected to corrosion testing. Materials that survive chemical testing are examined for electrochemical corrosion activity. For more stringent corrosion testing, and for further evaluation of electrocatalysts (which generally show significant O2 evolution at at 1.4 V), samples are held at 1.6 V or 0.6 V for about 100 hours. The surviving materials are then physically and chemically analyzed for signs of degradation. To evaluate the bifunctional oxygen activity of candidate catalysts, Teflon-bonded electrodes are fabricated and tested in a floating electrode configuration. Many of the experimental materials being studied have required development of a customized electrode fabrication procedure. In advanced development, the goal is to reduce the polarization to about 300 to 350 mV. Approximately six support materials and five catalyst materials were identified to date for further development. The test results will be described.
Document ID
19890013627
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Swette, L. (Giner, Inc. Waltham, MA, United States)
Kackley, N. (Giner, Inc. Waltham, MA, United States)
Date Acquired
September 5, 2013
Publication Date
January 1, 1989
Publication Information
Publication: NASA, Lewis Research Center, Space Electrochemical Research and Technology Conference: Abstracts
Subject Category
Energy Production And Conversion
Accession Number
89N22998
Funding Number(s)
CONTRACT_GRANT: NAS3-24635
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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