| abstract |
In a secondary battery using lithium nickel composite oxide particles as a positive electrode active material, cycle characteristics are improved without impairing charge / discharge capacity. As a positive electrode active material, a general formula: Li1 + uNixCoyAlzMtO2 (where -0.03≤u≤0.10, x + y + z + t = 1, 0.65 <x≤1.00, 0≤y≤0.35). , 0 ≦ z ≦ 0.10, 0 ≦ t ≦ 0.15, where M is one or more elements selected from Mn, Fe, Ti, V, Mg, Zr, Sr, and Si), lithium A primary active material having a content of alkali metal other than 0.5% by mass or less and comprising a lithium nickel composite oxide particle having a layered rock salt type structure, and having an average particle size of 0.8 to 15 μm Particles and / or secondary particles formed by agglomerating a plurality of the primary particles and having a lithium site occupancy of 3a site calculated by the Rietveld analysis method of 96.0% or more are used. [Selection] Figure 1 |