Secondary battery and secondary battery electrolyte used therein

Abstract

Provided is a lithium ion secondary battery in which a high-energy type negative electrode is used, the lithium ion secondary battery having high capacity and excellent thermal stability. A secondary battery according to the present embodiment comprises: an electrode element having a positive electrode and a negative electrode opposed each other; an electrolyte; and an outer casing containing the electrode element and the electrolyte, wherein the negative electrode comprises a negative electrode active material, which includes at least one of a metal (a) capable of alloying with lithium and a metal oxide (b) capable of occluding and releasing lithium ions, is bonded to a negative electrode current collector by a negative electrode bonding agent, and the electrolyte comprises 70˜99 vol % of a phosphoric acid ester compound and 1˜15 vol % of a fluorinated carbonate compound. A secondary battery electrolyte according to the present embodiment includes 70˜99 vol % of a phosphoric acid ester compound and 1˜15 vol % of a fluorinated carbonate compound.

Dependencies are inferred from the claim text.