| 摘要 |
PROBLEM TO BE SOLVED: To provide an active material for nonaqueous electrolyte secondary batteries excellent in high rate discharge performance, a manufacturing method thereof, and a nonaqueous electrolyte secondary battery using the active material.SOLUTION: Disclosed is an active material for nonaqueous electrolyte secondary batteries, the material containing a lithium transition metal composite oxide having an α-NaFeOtype crystal structure, the average composition of the lithium transition metal composite oxide being as expressed by a composition formula LiMeO(Me is a transition material containing Co, Ni, and Mn, α>0), the lithium transition metal composite oxide being particles having cores and coating parts, cobalt concentration of the coating parts being higher than that of the cores, manganese concentration of the coating parts being lower than that of the cores, the coating parts having gradients of the cobalt concentration, and starting points of cobalt concentration gradient areas form the surfaces of the particles is present at the positions between 0.1 and 0.5, where 0 represents the surface positions of the particles and 1 represents the central positions of the particles. The method of manufacturing the active material is mixing co-precipitation precursor particles of a transition metal compound with a lithium compound and calcining them, the transition metal compound having cobalt concentration gradient areas from the surface of particles. |
