Nickel - method for producing cobalt-containing complex compound

It can be used in a wide voltage range, high discharge capacity, high safety, charge-discharge cycle Durable a cathode active material for a lithium ion secondary battery precursor comprising less impurities nickel - inexpensive cobalt-containing complex compound to provide to. Heating the cobalt -M element-containing aqueous solution or aqueous dispersion, a nickel ammine complex and the cobalt ammine complex is thermally decomposed nickel - - nickel ammine complex, the cobalt ammine complex and M element source was formed by mixing nickel cobalt -M method for producing a cobalt -M element-containing complex compounds - nickel, characterized in that to produce the element-containing complex compounds.