Capacitor electrolyte

Claim 1

A liquid or semi-liquid electrolyte capacitor including anode electrode means of a valve metal, a valve metal oxide in contact with the anode electrode means, cathode electrode means, and electrolyte means contacting the valve metal oxide and the cathode electrode means, the electrolyte means comprising an organic solvent including glycol monoethers or diethers having up to 20 carbon atoms or amides having the formula ##EQU3## where R 1 , R 2 and R 3 are H or lower alkyl and mixtures thereof, the organic solvent has dissolved therein an ionizable solute of 0.01 wt.% up to the solubility limit of the organic solvent, the ionizable solute including acid at least partially neutralized and a neutralizing agent, the acid including boric acid or phosphoric acid or mono and dicarboxylic acids having up to 12 carbon atoms and mixtures thereof, the neutralizing agent including ammonia or alkyl and alkanol amines having 4 to 12 carbon atoms or guanidine type compounds having the formula ##EQU4## where R 4 and R 5 are lower alkyl or aryl or H, cyclic nitrogen compounds including pyridine or substituted pyridines and mixtures thereof, and a substance separate from the ionizable solute including acids or non-metal salts or chromium oxygen complexes and mixtures thereof, the substance yielding in solution chromate radicals having at least some solubility in the electrolyte to the extent of about 0.01% to about 2.5% by weight of the electrolyte.