6. A process for producing the Li-Ni composite oxide particles as claimed in any one of claims 1 to 4, comprising the steps of mixing lithium compound particles, Ni-Co hydroxide particles, and aluminum compound particles and/or zirconium compound particles, and calcining the resulting mixture, the Ni-Co hydroxide particles being produced by mixing an aqueous solution of a sulfuric acid salt of each metal element, an ammonia aqueous solution and a sodium hydroxide aqueous solution such that an ammonia concentration in a reaction vessel is controlled to not more than 1.4 mol/L, and a ratio of the ammonia concentration in the reaction vessel to a surplus hydroxyl group concentration in the reaction vessel is controlled to not less than 6.
ammonia
ammonia concentration
1.4 mol/L
mol/L