| 摘要 |
PROBLEM TO BE SOLVED: To provide a solid-solution positive electrode active material comprising a complex oxide, which is capable of maintaining high reversible capacity and reducing irreversible capacity, high in capacity and excellent in initial charge/discharge efficiency, and capable of being suitably used for an electrochemical device typified by a lithium ion secondary battery.SOLUTION: A solid-solution complex oxide is used as a positive electrode active material, the solid-solution complex oxide being represented by a composition formula: [Li][LiM'MnM]O(in the formula, x satisfies an expression of 0.1≤x≤0.5, M is represented as NiαCo&bgr;Mnγ, where 0<α≤0.5, 0≤&bgr;≤0.33 and 0<γ≤0.5 are satisfied, and M' represents at least on element selected from the group consisting of Mg, Zn, Al, Fe, Ti and V while the valence n thereof is 2 or more and 5 or less, and 0<ny<0.5 is satisfied). |
