Nonaqueous electrolyte solution and electricity storage device using same

A nonaqueous electrolytic solution having an electrolyte salt dissolved in a nonaqueous solvent, the nonaqueous electrolytic solution comprising from 0.001 to 5% by mass of a diisocyanate compound represented by the following general formula (I) and further comprising from 0.001 to 5% by mass of at least one selected from a phosphoric acid ester compound represented by the following general formula (II), a cyclic sulfonic acid ester compound represented by the following general formula (III), an isocyanate compound having an ester structure and represented by the following general formula (IV), and a triple bond-containing compound represented by the following general formula (V):

• OCN-L-NCO (I)
• wherein
• L represents an optionally branched alkylene group having from 4 to 12 carbon atoms,
• wherein
• each of R1 and R2 independently represents an alkyl group having from 1 to 6 carbon atoms or a halogenated alkyl group having from 1 to 6 carbon atoms, in which at least one hydrogen atom is substituted with a halogen atom;
• R3 represents an alkyl group having from 1 to 6 carbon atoms, an alkenyl group having from 2 to 6 carbon atoms, or an alkynyl group having from 3 to 6 carbon atoms;
• and each of R4 and R5 independently represents a hydrogen atom, a halogen atom, or an alkyl group having from 1 to 4 carbon atoms,
• wherein
• each of R6 and R7 independently represents a hydrogen atom, an alkyl group having from 1 to 6 carbon atoms, in which at least one hydrogen atom may be substituted with a halogen atom, or a halogen atom;
• X represents —CH(OR8)— or —C(═O)—;
• R8 represents a formyl group, an alkyl carbonyl group having from 2 to 7 carbon atoms, an alkenyl carbonyl group having from 3 to 7 carbon atoms, an alkynyl carbonyl group having from 3 to 7 carbon atoms, or an aryl carbonyl group having from 7 to 13 carbon atoms;
• and at least one hydrogen atom in R8 may be substituted with a halogen atom,
• wherein
• R9 represents an alkyl group having from 1 to 6 carbon atoms, an alkenyl group having from 2 to 6 carbon atoms, an aryl group having from 6 to 12 carbon atoms, an alkyloxy group having from 1 to 6 carbon atoms, an alkenyloxy group having from 2 to 6 carbon atoms, an isocyanatoalkyloxy group having from 2 to 6 carbon atoms, or an aryloxy group having from 6 to 12 carbon atoms, in each of which at least one hydrogen atom may be substituted with a halogen atom;
• and Y represents a linear or branched alkylene group having from 1 to 6 carbon atoms, in which at least one hydrogen atom may be substituted with a halogen atom, or a divalent linking group having from 2 to 6 carbon atoms and containing at least one ether bond, and
• Z—O—CH2—C≡C—W (V)
• wherein
• Z represents R10—O—C(═O)—, R11—O—C(═O)—C(═O)—, or R12—S(═O)2—;
• W represents a hydrogen atom or —CH2—O—S(═O)2—R13;
• each of R10 to R13 independently represents an alkyl group having from 1 to 6 carbon atoms, an alkenyl group having from 2 to 6 carbon atoms, an alkynyl group having from 2 to 6 carbon atoms, or an aryl group having from 6 to 12 carbon atoms, in each of which at least one hydrogen atom may be substituted with a halogen atom, provided that when Z is R10—O—C(═O)— or R11—O—C(═O)—C(═O)—, then W is a hydrogen atom.