| 摘要 |
PROBLEM TO BE SOLVED: To provide a positive electrode active material or use in a nonaqueous electrolyte secondary battery having increased initial capacity, without impairing formability and filling ability for a positive electrode, and a method for manufacturing it. SOLUTION: A Na-Li-Mn composite oxide is synthesized by mixing a manganese compound raw material comprising a spherical or elliptical secondary particle with a Na compound and a Li compound so as to keep it in shape, and the Na-Li-Mn composite oxide expressed by a formula of Nax [Liy Mn1-y ]O2 (where, 0.66<=x<=1.0, and 0<y<=0.18) is used as a precursor, the precursor is treated in a solution containing a Li ion or molten salt, and thereby a Na ion contained in the precursor is exchanged for a Li ion by ion exchange. The Na-Li-Mn composite oxide is obtained by mixing the Na compound, the Li compound and the Mn compound so that the mol ratio of Na, Li and Mn becomes x:y:1-y (where, 0.66<=x<=1.0, and 0<y<=0.18), and by applying heat treatment at 600<= or more for 10 hours or more and suddenly cooling it to a room temperature of less. |
