Non-aqueous electrolyte and lithium secondary battery using the same
AssigneeHitachi, Ltd.
InventorsToshiyuki Kobayashi, Kazushige Kohno
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Abstract
A non-aqueous electrolyte and a lithium secondary battery using the same are provided, which satisfy both flame retardancy and charge-discharge cycle characteristics, and attain a longer lifetime of the battery. A mixture of a chain carbonate, vinylene carbonate, a fluorinated cyclic carbonate and a phosphate ester is used as the non-aqueous electrolyte. It is desirable that the phosphate ester includes trimethyl phosphate and a fluorinated phosphate ester. Further, it is desirable that ethylene carbonate is further contained.
Claims5
A non-aqueous electrolyte, comprising a chain carbonate, vinylene carbonate, a fluorinated cyclic carbonate, a phosphate ester, ethylene carbonate and a supporting electrolyte;
- wherein the phosphate ester comprises trimethyl phosphate and a fluorinated phosphate ester;
- the chain carbonate is ethyl methyl carbonate or dimethyl carbonate;
- the supporting electrolyte is LiPF6;
- the fluorinated cyclic carbonate is fluoroethylene carbonate;
- wherein an additive amount of the phosphate ester is 1 to 15% by weight and an additive amount of the fluorinated phosphate ester is 0.5 to 6% by weight;
- and
- wherein the fluorinated phosphate ester is tris(2,2,2 -trifluoroethyl) phosphate.
Dependencies are inferred from the claim text.