| abstract |
Provided is a lithium secondary battery which can be stably used even when continuous charging is continued at a high voltage of 4.3 V or higher. General formula Li 1 + y Ni 1 -a- b-c Co a Mn b M 1 c O 2 [stage, M 1 is Mg, Al, Ti, Fe, Cu, Zn, Ga, Ge, Zr, Nb, Mo , Sn, W, B, P and Bi, and satisfies -0.15? Y? 0.15, 0.05? A? 0.3, 0.05? B? 0.3, 0? C? 0.03 and a + b + c? 0.5) and a material containing Si and O as a constituent element (provided that the atomic ratio (x) of O to Si is 0.5? X? 1.5), and the positive electrode containing a lithium- A nonaqueous electrolyte containing a compound having a nitrile group in the molecule, and a separator. The lithium secondary battery according to the present invention solves the above problems. |