Hybrid electrode for metal-air cells - using carbon layer contg. silver doped with metal hydroxide, to increase electrode life

摘要

Hybrid electrode for metal/air cells where, on the electrolyte side is a hydrophilic Ni layer (a) for O2 pptn; on the gas side is a hydrophobic layer (c) of plastic; and between layers (a,c) is a hydrophobic carbon layer (b) for the dissolution of O2. Layer (b) contains silver doped with the hydroxides of Ti, Ni and Bi. Layer (b) pref. contains by wt. 20-60% esp. 30-50% Ag w.r.t. the catalytically active material, the Ag, contg. 0.5-5 wt.% hydroxides, esp. 0.1% Ti, 0.4-0.5% Ni and 0.7-0.8% Bi. The carbon may also be activated with NH3, and/or coated with 10-25% Ag. The carbon-silver electrocatalyst is pref. made from a suspension of carbon in a weak acid aq. soln. contg. an Ag-, Ti-, Ni-, and a Bi-salt, plus formaldehyde. This suspension is fed dropwise with stirring and cooling into an aq. alkali hydroxide soln. followed by sepn. of the catalyst. Provides an electrode with increased life and improved discharge voltage.