Non-aqueous liquid electrolyte for secondary battery and secondary battery

1. A non-aqueous liquid electrolyte for a secondary battery, comprising:

at least one selected from a sulfur-containing ring compound and/or a carbonate compound having a halogen atom;

an aromatic ketone compound;

an organic solvent; and

an electrolyte salt,

wherein, with respect to 100 parts by mass of the organic solvent, the aromatic ketone compound is 0.001 to 10 parts by mass and the at least one selected from a carbonate compound having a halogen atom and a sulfur-containing ring compound is 0.001 to 10 parts by mass, and

more than 50% by mass of the whole amount of the organic solvent comprises a solvent with a melting point of 10° C. or less,

wherein the carbonate compound containing a halogen atom is a compound represented by the following formula (F2):

wherein R G and R H represent an alkyl group, any one of R G and R H has a halogen atom, and an oxy group may exist in the alkyl group,

wherein the sulfur-containing ring compound is represented by the following formula (S1-1), (S2-1) or (S3-1):

wherein X 1 and X 2 represent —O— or —C(Ra)(Rb)—, and

wherein the skeleton of the 5- or 6-membered ring formed by a includes a sulfur atom and a carbon atom and optionally an oxygen atom,

wherein the aromatic ketone compound is a compound represented by the following formula (1):

wherein R 1 and R 2 represent an aromatic group; and R 1 and R 2 may bind to each other directly or via a linking group to form a 5- to 8-membered ring containing C═O of formula (1), and may form a multimer.

2. The non-aqueous liquid electrolyte for a secondary battery according to claim 1 , wherein the solvent with a melting point of 10° C. or less contains a compound having a chain carbonate structure or an ester structure.

3. The non-aqueous liquid electrolyte for a secondary battery according to claim 1 , wherein the organic solvent is composed of a compound except the carbonate compound having a halogen atom, the sulfur-containing ring compound, and the aromatic ketone compound.

4. The non-aqueous liquid electrolyte for a secondary battery according to claim 1 , wherein the organic solvent is composed of an atom selected from a carbon atom, a hydrogen atom, an oxygen atom, a nitrogen atom, a phosphorus atom, and a boron atom.

5. The non-aqueous liquid electrolyte for a secondary battery according to claim 1 , wherein the aromatic ketone compound represented by formula (1) is a compound represented by the following formula (2):

wherein R represents a substituent; and n represents an integer of 0 to 8.

6. The non-aqueous liquid electrolyte for a secondary battery according to claim 1 , wherein the aromatic ketone compound represented by formula (1) is a compound represented by any one of the following formulae (1-1) to (1-24):

wherein the compound represented by each of the formulae may be substituted or unsubstituted.

7. A lithium secondary battery using the non-aqueous liquid electrolyte for a secondary battery according to claim 1 .

8. The non-aqueous liquid electrolyte for a secondary battery according to claim 1 , wherein the carbonate compound having a halogen atom is represented by any one of the following formulae FC-7 to FC-12:

and the sulfur-containing ring compound is the compound represented by formula (S1-1) or (S3-1).