| 摘要 |
1,171,708. Fuel cell electrodes. ALLISCHALMERS MFG. CO. 14 Aug., 1967 [23 Aug., 1966], No. 37263/67. Heading H1B. A fuel cell electrode is prepared by forming a slurry of electrically conductive particles which are catalytic for a fuel cell reaction in a liquid emulsion of a thermoplastic resin, precipitating the particles, now coated with a discontinuous film of resin, from the slurry, mixing the precipitate with an aqueous solution of a surfactant, agitating the mixture to form a foamed mass, separating the coated particles from the foamed mass to form a mat and compressing the mat into a cohesive mass to form an electrode. Suitable particles may be of carbon or a metal of Groups IB, IIB, or III-VIII or a rare earth metal, e.g. Al, Cu, Ni, Co, Fe, Ag, Au, Pd, Pt, Os, Ir, Ta, Ti, Mn, Zr. Suitable resins include polytetrafluoroethylene, polychlorotrifluoroethylene, polyethylene, polypropylene and polystyrene, in aqueous emulsion of the resin itself or of a solution of the resin, e.g. polystyrene in benzene. P.T.F.E., for example, may amount to 1-30 wt. per cent of the resin/particle mixture. Suitable surfactants include sorbitan monolaurate, polyoxyethylene sorbitan monostearate, nonyl- or hexadecyl-phenol polyoxyethylene ethers, sodium alkylphenol polyether sulphates, alkylaryl sulphonates, n-dodecyl trimethylammonium chloride, di-n-octadecyl dimethylammonium chloride and polyoxyethylene primary fatty amines. Coagulants for the slurry may be, e.g., MeOH, EtOH, NaOH, KOH, MEK and HNO 3 . The electrode may be supported on, e.g., a nickel screen, non-woven screen, perforated sheet, metal fibre paper or metal fibre mat. In examples, Ag and Ni particles are slurried with aqueous (35%) P.T.F.E. emulsion containing iso-octylphenoxy polyethylenoxy ethanol, precipitated with acetone, the mixture is foamed and filtered, and the resultant mat pressed on to a nickel screen. The Ag electrode is used as cathode in a H 2 /O 2 fuel cell having a 20-20 Pt/Pd catalysed porous sintered Ni anode and 30% aqueous KOH electrolyte. |
