Nonaqueous electrolytic solution and nonaqueous electrolytic solution secondary battery

A nonaqueous electrolytic solution for nonaqueous electrolytic solution secondary batteries, the nonaqueous electrolytic solution comprising:

• a nonaqueous solvent,
• an electrolyte dissolved in the nonaqueous solvent,
• (I) a difluoro ionic complex (1) represented by the general formula (1), and
• (II) at least one compound selected from the group consisting of a cyclic phosphazene compound represented by the general formula (II-1) below, a siloxane compound represented by the general formula (II-2) below, an aromatic compound represented by the general formula (II-3) below, a cyclohexene compound represented by the general formula (II-4) below, a phosphoric acid ester compound represented by the general formula (II-5) below, a fluorinated linear ether compound represented by the general formula (II-6) below, a fluorinated cyclic ether compound represented by the general formula (II-7) below, and a boric acid ester compound represented by the general formula (II-8) below,
• wherein 95 mol % or more of the difluoro ionic complex (1) is a difluoro ionic complex (1-Cis) in a cis configuration represented by the general formula (1-Cis),
• wherein in (1-Cis),
• wherein in the general formula (1) and the general formula (1-Cis),
• A+ is any one selected from the group consisting of a metal ion, a proton, and an onium ion, and M is any one selected from the group consisting of Si, P, As, and Sb;
• F is a fluorine atom;
• O is an oxygen atom;
• t is 2 when M is Si, and t is 1 when M is P, As, or Sb;
• X is an oxygen atom or —N(R1)—;
• N is a nitrogen atom;
• and R1 is a hydrocarbon group having 1 to 10 carbon atoms and optionally having a hetero atom and/or a halogen atom (the hydrocarbon group optionally having a branched-chain or ring structure when the number of carbon atoms is 3 or more);
• when X is —N(R1)—, and p is 0, X and W are bonded directly and optionally form a structure as shown in at least one selected from the general formulas (1-Cis-1) to (1-Cis-3) below;
• in the case of the general formula (1-Cis-2) below where the direct bond is a double bond, R1 is not present,
• Y is a carbon atom or a sulfur atom;
• q is 1 when Y is a carbon atom;
• q is 1 or 2 when Y is a sulfur atom;
• W represents a hydrocarbon group having 1 to 10 carbon atoms and optionally having a hetero atom and/or a halogen atom (the hydrocarbon group optionally having a branched-chain or ring structure when the number of carbon atoms is 3 or more), or —N(R2)—;
• wherein, R2 represents a hydrogen atom, an alkaline metal, or a hydrocarbon group having 1 to 10 carbon atoms and optionally having a hetero atom and/or a halogen atom;
• when the number of carbon atoms is 3 or more, R2 optionally has a branched-chain or ring structure;
• p is 0 or 1, q is an integer of 0 to 2, r is an integer of 0 to 2, and further, p+r≥1,
• wherein
• in the general formula (II-1), R1 to R6 are each independently a substituent selected from the group consisting of a halogen atom, an amino group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, and an aryloxy group having 6 to 12 carbon atoms;
• n1 is an integer of 1 to 10;
• and the alkyl group, the alkoxy group, and the aryloxy group optionally have a hetero atom and/or a halogen atom;
• in the general formula (II-2), R7 to R12 are each independently a substituent selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkenyloxy group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an alkynyloxy group having 2 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, and an aryloxy group having 6 to 12 carbon atoms, said groups optionally having a hetero atom and/or a halogen atom;
• n2 is an integer of 1 to 10;
• when n2 is 2 or more, R11's and R12's independently are optionally the same as or different from one another;
• a group represented by OR7 and a group represented by OR8 are optionally bonded to each other to form a siloxane bond;
• and the siloxane compound represented by the general formula (II-2) includes a siloxane compound represented by the general formula (II-2′);
• and
• in the general formula (11-2′), R13 and R14 are each independently a substituent selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkenyloxy group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an alkynyloxy group having 2 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, and an aryloxy group having 6 to 12 carbon atoms, said groups optionally having a hetero atom and/or a halogen atom;
• n3 is an integer of 2 to 10;
• R13's and R14's independently are optionally the same as or different from one another;
• wherein
• in the general formula (II-3), R15 to R20 are each independently a substituent selected from the group consisting of a hydrogen atom, a halogen atom, and a hydrocarbon group having 1 to 12 carbon atoms;
• and at least two of R15 to R20 are optionally bonded to one another to form a ring;
• and
• in the general formula (II-4), R21 to R24 are each independently a substituent selected from the group consisting of a hydrogen atom, a halogen atom, and a hydrocarbon group having 1 to 12 carbon atoms;
• and at least two of R21 to R24 are optionally bonded to one another to form a ring;
• wherein
• in the general formula (II-5), R25 to R27 are each independently a substituent selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, a cyano group, an amino group, a nitro group, an alkoxy group having 1 to 10 carbon atoms, and a cycloalkyl group having 3 to 10 carbon atoms, said groups optionally having a hetero atom and/or a halogen atom;
• and any two or all of R25, R26, and R27 are optionally bonded to one another to form a ring structure;
• in the general formula (II-6), R28 and R29 are each independently a substituent selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a fluorinated alkyl group having 1 to 10 carbon atoms, a fluorinated cycloalkyl group having 3 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms and having an ethereal oxygen atom between the carbon atoms, and a fluorinated alkyl group having 1 to 10 carbon atoms and having an ethereal oxygen atom between the carbon atoms;
• and at least one of R28 and R29 contains a fluorine atom;
• in the general formula (II-7), R32 is a substituent selected from the group consisting of an alkylene group having 1 to 5 carbon atoms, a fluorinated alkylene group having 1 to 5 carbon atoms, an alkylene group having 1 to 5 carbon atoms and having an ethereal oxygen atom between the carbon atoms, and a fluorinated alkylene group having 1 to 5 carbon atoms and having an ethereal oxygen atom between the carbon atoms;
• R30 and R31 are each independently a substituent selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a fluorinated alkyl group having 1 to 10 carbon atoms, a fluorinated cycloalkyl group having 3 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms and having an ethereal oxygen atom between the carbon atoms, and a fluorinated alkyl group having 1 to 10 carbon atoms and having an ethereal oxygen atom between the carbon atoms;
• and at least one of R30 and R31 contains a fluorine atom;
• and
• in the general formula (II-8), R33 to R35 are each independently a fluorinated alkyl group having 1 to 10 carbon atoms.