Patent ID: 8163195

Claim:
An electric double layer capacitor comprising, an electrolytic solution comprising an electrolyte and an additive, wherein the additive is dimethyl 1,3-acetone-dicarboxylate, diethyl 1,3-acetonedicarboxylate, indanedione, trimethyl aconitate, triethylmethanetricarboxylic acid, ethyldimethylmethanetricarboxylic acid, diethylmethylmethane-tricarboxylic acid, methyldiisopropylmethanetricarboxylic acid, trimethylmethanetricarboxylic acid, N,N,N′,N′-tetramethylmalonamide, N,N,N′,N′-tetraethylmalonamide, methyl 3-oxoheptanoate, methyl 3-oxopentanoate or methyl cyclopentanone-2-carboxylate.