Abstract: An electrolyte for electrolytic capacitors comprises an alkyl glycol of 2 to 4 carbons; ammonium formate; and either a dicarboxylic acid of 2 to 8 carbons or its diammonium salt, wherein the ammonium ion is of the formula NH--(R).sub.3 in which R is H, or alkyl or alkanol of 1 to 7 carbons.

Abstract: An essentially non-aqueous electrolyte composition for aluminum-anode capacitors is disclosed comprising ethylene glycol and a salt such as the ammonium or amine salt of an unsaturated dicarboxylic acid with or without a small amount of an additive such as boric acid, phosphoric acid, ammonium dihydrogen phosphate, ammonium pentaborate, ammonium phosphate and mixtures thereof. The electrolyte offers high electrical conductivity, and greatly increased stability and shelf life, under conditions of no voltage, for low voltage capacitors having high capacitance ratings. In one embodiment, the combination of ethylene glycol, as the solvent, with between about 0.001 to 0.1 mole of unsaturated dicarboxylic acid per mole of ethylene glycol and about 0.001 to 0.1 mole of the salt per mole of ethylene glycol is used. Other embodiments are disclosed.