abstract |
A non-aqueous electrolyte secondary battery capable of further improving safety is provided. A composite metal oxide capable of doping and dedoping M 1 (M 1 is an alkali metal element) ion, and an M 3 -containing compound (M 3 is placed in the form of particles or layers on the surface of the oxide) The positive electrode active material is a granular positive electrode active material composed of a Group 3B element, and the positive electrode active material has M 1 (M 1 is the above), M 2 (M 2 is Mn, Fe, Co, and Ni) on the surface thereof. ), M 3 (M 3 is the above) and O, and the molar ratio (M 3 / M 2 ) between the number of M 3 atoms (mol) and the number of M 2 atoms (mol) on the surface is A, and the positive electrode When the active material has a BET specific surface area of S (m 2 / g), A and S contain a positive electrode active material that satisfies the following formula (1): A negative electrode, A separator; A non-aqueous electrolyte, A non-aqueous electrolyte secondary battery. A / S ≧ 1 (1) [Selection figure] None |