Patent ID: 7709156

Claim:
A non-aqueous electrolyte secondary battery comprising: a positive electrode containing a positive electrode active material; a negative electrode containing a negative electrode active material; a non-aqueous electrolyte containing a non-aqueous solvent and an electrolyte salt; wherein the positive electrode active material contains a layered lithium-transition metal composite oxide containing at least one element selected from the group consisting of Mg, Al, Ti, and Zr; and the non-aqueous electrolyte contains 3 to 80% by mass of a tertiary carboxylic acid ester expressed by Chemical Formula 2 below, based on the total mass of the non-aqueous solvent: where R1 to R4 are independent of each other and each represents an alkyl group having 4 or less carbon atoms and being able to be branched; wherein the layered lithium-transition metal composite oxide is at least one selected from the group consisting of a lithium-cobalt composite oxide, a lithium-nickel composite oxide, a lithium-cobalt-nickel composite oxide, a lithium-manganese-nickel composite oxide, and a lithium-cobalt-manganese-nickel composite oxide; and wherein the at least one element selected from the group consisting of Mg, Al, Ti and Zr contained in the layered lithium-transition metal composite oxide is 0.005 to 0.8% in total, based on the total mole number of the transition metal and the element contained in the layered lithium-transition metal composite oxide.