| abstract |
To provide a positive electrode active material of a lithium ion battery which has a large discharge capacity, excellent cycle characteristics, and suppressed gas generation. Resolution Means: A lithium metal composite oxide powder for use in a positive electrode active material for a lithium ion battery, the powder thereof having a composition of Li a Ni b Co c Al d O 2 (wherein, a = 0.8 to 1.2, b = 0.7 to 0.95, c = 0.02 to 0.2, d = 0.005 to 0.1, and b + c + d = 1) treated with an aqueous solution of an organic metal salt and soluble aluminum salt, and not causing volume expansion due to gas generation. |