Nonaqueous electrolyte secondary battery

Abstract

A nonaqueous electrolyte secondary battery comprising a negative electrode constituted of a carbonaceous material permitting reversible insertion and desorption of lithium, a positive electrode permitting reversible insertion and desorption of lithium, a separator separating these positive electrode and negative electrode from each other and a nonaqueous electrolyte composed of an organic solvent and, dissolved therein, a solute of lithium salt, wherein the nonaqueous electrolyte contains vinylene carbonate and di(2-propynyl) oxalate, these vinylene carbonate and di(2-propynyl) oxalate added in an amount of 0.1 to 3.0% by mass and 0.1 to 2.0% by mass, respectively, based on the mass of the nonaqueous electrolyte. Thus, there can be provided a nonaqueous electrolyte secondary battery wherein a stable SEI surface coating is formed to thereby exhibit a large initial capacity and excel in cycle characteristics at high temperature and wherein any cell swelling is slight.

Dependencies are inferred from the claim text.