Cathode active material for lithium-ion battery and producing method thereof

Abstract

Provided is a cathode active material for a lithium-ion battery that can reduce gas generation in the cathode and exhibits an excellent filling property. Also provided is a method of producing a cathode active material for a lithium-ion battery, the method including preparing a mixture comprising a lithium transition metal composite oxide having a layered structure, containing lithium and nickel in a composition, and containing secondary particles formed by aggregation of a plurality of primary particles, the secondary particles having a volume-average particle diameter greater than 3 μm and less than 5 μm, and a treatment solution containing a sulfate ion and a liquid medium, a concentration of the sulfate ion being in a range of 1 mass % to 9 mass %; and removing the treatment solution from the mixture.

Dependencies are inferred from the claim text.