Optimization of PT-Doped Kocite(R) (Trademark) Electrodes in H3PO4 Fuel Cells.
Interim progress rept. no. 2, Feb-Aug 76,
UOP INC DES PLAINES ILL
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The use of UOP Pt-impregnated Kocite materials as low cost air andor fuel electrocatalysts in phosphoric acid electrolyte fuel cells is being optimized. KociteR materials are composite structures consisting of pyropolymers chemically bonded to refractory substrates. Fuel cell electrodes are fabricated from those materials and tested as anodes or cathodes in model fuel cells with Teflon bonded Pt black counter electrodes. Kocite is being produced in 200-400 gram quantities from a high surface area alumina with a particle size of about 500 nm. From the Pt-impregnated Kocite, electrodes with a porous graphite paper current collector are being fabricated by both hand and machine calendering operations with 0.125, 0.25, and 0.50 mgsq cm Pt loadings. When tested in model phosphoric acid fuel cells with 2 mgsq cm Pt black counter electrodes, full-cell IR-free performances of 0.62 and 0.71 volts as air and oxygen cathodes, respectively, have been obtained at 100 masq cm and 149C using 0.25 mgsq cm Pt-loaded Kocite electrodes. Lifetime testing of Kocite electrodes as cathodes indicates no catalyst deterioration occurs for periods in excess of 500 hours for temperatures from 140 to 180C. In order to optimize the structure of Kocite electrodes, the teflon content, density, and thickness of the Kocite catalyst layer have been systematically varied.
- Electric Power Production and Distribution