Abstract: To provide an electrolytic solution that suppresses increase in the OH? ion concentration even in the case of electrochemical changes and thereby reduces deterioration or corrosion of resin, rubber, or metal to improve the reliability of an electrochemical device, an electrolyte used in the electrolytic solution, and an electrochemical device comprising the electrolytic solution. The electrolyte, for example, comprises a compound having a cation unit represented by the following formula and an electrolyte (a quaternary ammonium salt or the like). (In the formula, R1, R2, R3, and R4 are the same or different and each represent an alkyl group or an alkoxyalkyl group; R1 and R2 may together form a ring such as a pyrrolidine ring and a piperidine ring; and R3 and R4 may together form a ring such as a pyrrolidine ring and a piperidine ring.

Abstract: The present invention provides a nonaqueous electrolytic solution that provides an electric double layer capacitor having excellent durability. The nonaqueous electrolytic solution of the present invention is a nonaqueous electrolytic solution for electric double layer capacitors prepared by dissolving a quaternary ammonium salt as an electrolyte in a nonaqueous solvent, and the nonaqueous electrolytic solution has an alkali metal cation concentration of 0.1 to 30 ppm.

Abstract: To provide an electrolytic solution that suppresses increase in the OH? ion concentration even in the case of electrochemical changes and thereby reduces deterioration or corrosion of resin, rubber, or metal to improve the reliability of an electrochemical device, an electrolyte used in the electrolytic solution, and an electrochemical device comprising the electrolytic solution. The electrolyte, for example, comprises a compound having a cation unit represented by the following formula and an electrolyte (a quaternary ammonium salt or the like). (In the formula, R1, R2, R3, and R4 are the same or different and each represent an alkyl group or an alkoxyalkyl group; R1 and R2 may together form a ring such as a pyrrolidine ring and a piperidine ring; and R3 and R4 may together form a ring such as a pyrrolidine ring and a piperidine ring.

Abstract: Provided is a nonaqueous electrolytic solution that provides an electric double layer capacitor having excellent durability. The nonaqueous electrolytic solution is prepared by dissolving a quaternary ammonium salt as an electrolyte in a nonaqueous solvent, and the nonaqueous electrolytic solution comprises a diethylpyrrolidinium salt and/or a 1-ethyl-1,3-dimethylpyrrolidinium salt.

Abstract: The present invention provides a nonaqueous electrolytic solution that provides an electric double layer capacitor having excellent durability. The nonaqueous electrolytic solution of the present invention is a nonaqueous electrolytic solution for electric double layer capacitors prepared by dissolving a quaternary ammonium salt as an electrolyte in a nonaqueous solvent, and the nonaqueous electrolytic solution has an alkali metal cation concentration of 0.1 to 30 ppm.

Abstract: Provided is a nonaqueous electrolytic solution that provides an electric double layer capacitor having excellent durability. The nonaqueous electrolytic solution is prepared by dissolving a quaternary ammonium salt as an electrolyte in a nonaqueous solvent, and the nonaqueous electrolytic solution comprises a diethylpyrrolidinium salt and/or a 1-ethyl-1,3-dimethylpyrrolidinium salt.

Abstract: An additive of the formula (1) for use in electrolytic solutions wherein A is —CH(X)— or —C?C(X)—, X being hydrogen, halogen, alkyl having 1 to 4 carbon atoms, alkoxycarbonyl having 2 to 5 carbon atoms, benzoyl or alkoxycarbonylalkyl having 3 to 9 carbon atoms, Q1 and Q2 are the same or different and are each alkyl having 1 to 6 carbon atoms, alkoxyl having 1 to 4 carbon atoms, alkoxycarbonylalkyl having 3 to 9 carbon atoms or amino having as a substituent alkyl having 1 to 4 carbon atoms, and A, Q1 and Q2 may form a ring structure.

Abstract: An additive of the formula (1) for use in electrolytic solutions wherein A is —CH(X)— or —C?C(X)—, X being hydrogen, halogen, alkyl having 1 to 4 carbon atoms, alkoxycarbonyl having 2 to 5 carbon atoms, benzoyl or alkoxycarbonylalkyl having 3 to 9 carbon atoms, Q1 and Q2 are the same or different and are each alkyl having 1 to 6 carbon atoms, alkoxyl having 1 to 4 carbon atoms, alkoxycarbonylalkyl having 3 to 9 carbon atoms or amino having as a substituent alkyl having 1 to 4 carbon atoms, and A, Q1 and Q2 may form a ring structure.

Abstract: An additive of the formula (1) for use in electrolytic solutions wherein A is —CH(X)— or —C?C(X)—, X being hydrogen, halogen, alkyl having 1 to 4 carbon atoms, alkoxycarbonyl having 2 to 5 carbon atoms, benzoyl or alkoxycarbonylalkyl having 3 to 9 carbon atoms, Q1 and Q2 are the same or different and are each alkyl having 1 to 6 carbon atoms, alkoxyl having 1 to 4 carbon atoms, alkoxycarbonylalkyl having 3 to 9 carbon atoms or amino having as a substituent alkyl having 1 to 4 carbon atoms, and A, Q1 and Q2 may form a ring structure.

Abstract: An electrolyte solution for electric double layer capacitors, which comprises the following (a) and (b): (a) a compound represented by the formula (1), (b) a mixed solvent comprising ethylmethyl carbonate, at least one kind selected from chain carbonates other than ethylmethyl carbonate, and at least one kind selected from cyclic carbonates, (wherein R1 and R2 may be the same or different and independently denote methyl, ethyl, methoxymethyl or ethoxymethyl, or may form a ring structure).

Abstract: An additive of the formula (1) for use in electrolytic solutions wherein A is —CH(X)— or —C?C(X)—, X being hydrogen, halogen, alkyl having 1 to 4 carbon atoms, alkoxycarbonyl having 2 to 5 carbon atoms, benzoyl or alkoxycarbonylalkyl having 3 to 9 carbon atoms, Q1 and Q2 are the same or different and are each alkyl having 1 to 6 carbon atoms, alkoxyl having 1 to 4 carbon atoms, alkoxycarbonylalkyl having 3 to 9 carbon atoms or amino having as a substituent alkyl having 1 to 4 carbon atoms, and A, Q1 and Q2 may form a ring structure.