| 摘要 |
PROBLEM TO BE SOLVED: To prevent a capacity from being lowered due to repetition of charging and discharging and improve durability by substituting an oxygen ion existing in Li compound as a positive electrode material for the other negative ion different from the above ion. SOLUTION: A material expressed by composition formula of LiXMe2 O4-y Yy is used for a positive electrode for lithium secondary battery. In this formula, x is greater than 0 and is smaller 3, y is greater than 0 and is smaller than 2, Me is at least one type to be selected from Mn, Fe, Co, and Ni, and Y is an anion. The anion Y is at least one type to be selected from F, Cl, Br, and I. This positive electrode material having the spinel structure can adjust the Me-ion value number by substituting the oxygen ion for the anion. Structure phase transition is hardly generated in the crystal of the positive electrode material by substitution of the oxygen ion. Therefore, even if charging and discharging are repeated, the structure phase transition from the cubic crystal to the tetragonal crystal is restricted while it is shifted to the high capacity, side, and the lowering of the discharge voltage is alleviated. |
