AQUEOUS SOLUTION AND METHOD FOR PRODUCING CATHODE ACTIVE MATERIAL FOR LITHIUM SECONDARY BATTERIES

An aqueous solution contains Li, a peroxo complex of an element α, an ammonium ion, and a nitrate ion, in which the element α is one or more elements selected from the group consisting of Nb, Ti, Ta, Zr, W, Mo, and V, and in the aqueous solution, a ratio (NH/α) of a mass molar concentration of the ammonium ion to a mass molar concentration of the element α is less than 4.5, and a mass molar concentration of the nitrate ion (NO) is less than 4.0×10mol/kg.