Non-aqueous electrolyte and energy storage device using the same

Abstract

The present invention relates to: a nonaqueous electrolyte solution which contains an electrolyte salt and a phosphonic acid ester that is represented by general formula (I), and which satisfies at least one of the condition (A) and the condition (B) described below; and a power storage device which comprises a positive electrode, a negative electrode and the nonaqueous electrolyte solution. (In general formula (I), R1 represents an alkyl group, and each of R2 and R3 independently represents an alkynyl group having 3 to 6 carbon atoms.) Condition (A): In the formula, R1 is an alkyl group having 1 to 5 carbon atoms; at least one selected from among an anion-containing compound having an S=O bond and an S=O group-containing compound (excluding the anion-containing compound having an S=O bond) is additionally contained; and if (A1) is the content of a compound represented by general formula (I) on a mass basis, (A2) is the content of an anion-containing compound having an S=O bond on a mass basis, and (A3) is the content of an S=O group-containing compound on a mass basis, at least one of [(A1) / (A2) is 0.001 to 10], and [(A1) / (A3) is 0.001 to 1.5], is satisfied. Condition (B): In the formula, R1 is a branched alkyl group having 3 to 6 carbon atoms; and a carbon atom adjacent to a phosphorus atom is a secondary carbon atom or a tertiary carbon atom.

Claims

1. A non-aqueous electrolyte containing an electrolyte salt and a phosphonic acid ester represented by the following general formula (I), and satisfying at least one of the following conditions (A) and (B). 【Chemistry 1】 (In general formula (I), R １ R represents an alkyl group, ２ and R ３ Each of these independently represents an alkynyl group with 3 to 6 carbon atoms. Condition (A): R １ These are alkyl groups having 1 to 5 carbon atoms. Furthermore, it contains at least one selected from an anion-containing compound having an S=O bond and an S=O group-containing compound (excluding the aforementioned anion-containing compound having an S=O bond), When [A1] is the mass-based content of the compound represented by general formula (I), [A2] is the mass-based content of the anion-containing compound having an S=O bond, and [A3] is the mass-based content of the compound containing an S=O group, at least one of the following conditions is met: [A1] / [A2] is 0.001 or more and 10 or less, and [A1] / [A3] is 0.001 or more and 1.5 or less. Condition (B): R １ It is a branched alkyl group having 3 to 6 carbon atoms, where the carbon atoms adjacent to the phosphorus atom are secondary or tertiary carbon atoms.

2. The anion-containing compound having the S=O bond is FSO ３ － , (FSO ２ ), ２ N － , (FSO ２ )(CF ３ SO ２ ), N － , (FSO ２ ), ３ C － , and CH ３ SO ４ － The non-aqueous electrolyte according to claim 1, which is at least one selected from the group consisting of.

3. The non-aqueous electrolyte according to claim 1, wherein the S=O group-containing compound is a cyclic sulfonic acid ester compound or a cyclic sulfate ester compound.

4. The non-aqueous electrolyte according to claim 3, wherein the S=O group-containing compound is 1,3-propanesultone or 1,2-ethylene sulfate.

5. R in the above general formula (I) １ The non-aqueous electrolyte according to claim 1, wherein the group is a methyl group, an ethyl group, an isopropyl group, an n-butyl group, a sec-butyl group, or a tert-butyl group.

6. R in the above general formula (I) ２ and R ３ The non-aqueous electrolyte according to claim 1, wherein each of the groups is independently selected from 2-propynyl group, 2-butynyl group, 3-butynyl group, 1-methyl-2-propynyl group, 1,1-dimethyl-2-propynyl group, and 1-ethyl-1-methyl-2-propynyl group.

7. An energy storage device having a positive electrode, a negative electrode and a non-aqueous electrolyte, wherein the non-aqueous electrolyte is the non-aqueous electrolyte described in any one of claims 1 to 6.

8. The energy storage device according to claim 7, wherein the positive electrode has a lithium composite metal oxide as a positive electrode active material, and the transition metal oxide includes a transition metal oxide in which the ratio of the atomic concentration of Ni to the atomic concentration of all transition metal elements in the positive electrode active material is 30 atomic% or more.

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