CAPACITOR HAVING ELECTRODE COATED WITH CONDUCTIVE SOLID POLYMER ELECTROLYTE

1,225,601. Electrolytic capacitors. GENERAL ELECTRIC CO. 1 Jan., 1969 [2 Feb., 1968], No. 139/69. Heading H1M. A capacitor comprises electrode 2 having a dielectric oxide film 3 and, coating the oxide film, a layer 4 of a solid electrolyte consisting of a nitrogen-containing polymer selected from polyurethanes, polyvinyl pyrridines, acrylonitrile and methacrylonitrile polymers, having dissolved therein sufficient quantities of 7,7,8,8- tetracyanodiquinodimethan and a salt thereof to give the polymer a conductivity greater than 10-3 mho per cm. As shown, electrode 2 is an anolizable metal foil and the coated foil is wound to form the capacitor, lead 5 being embedded in the polymeric layer and lead 6 connected to or integral with electrode 2. Part at least of the polymer coating may be coated with graphite, metal paint or electroplated metal to make connection with a metal can. The anode may alternatively be a porous sintered pellet (Figs. 3, 4, not shown), or stacked sheets or wire. The cation of the salt may be organic or inorganic, and the ionized and unionized tetracyanodiquinodimethan may both be present in a complex salt, e.g. with quinoline.