Processes for making positive active material for lithium secondary batteries and secondary batteries therefor

A process for making positive active materials for lithium secondary batteries comprising lithium containing oxides, nickel and manganese, represented by a formula LiNi.sub.x Mn.sub.(1-x) O.sub.2, where the value x is 0.95.gtoreq.x.gtoreq.0.70;

• comprising the steps of forming composite hydroxides comprising manganese and nickel through co-precipitation of manganese and nickel hydroxides by adding caustic alkali aqueous solutions to mixed aqueous solutions containing manganese and nickel salts, mixing said composite hydroxides with lithium compounds and burning said mixture.

A process for making lithium secondary batteries;

• comprising the steps of forming composite hydroxides comprising cobalt and nickel through co-precipitation of cobalt and a nickel hydroxides by adding caustic alkali aqueous solutions to mixed aqueous solutions containing cobalt and nickel salts, mixing said composite hydroxides with lithium compounds and burning said mixture to make positive active materials, forming a paste containing said positive active materials and coating said paste on aluminum foils for use as the positive electrodes for the batteries.

A process for making lithium secondary batteries;

• wherein composite hydroxides comprising manganese and nickel are formed by the steps of co-precipitation of manganese and nickel hydroxides by adding caustic alkali aqueous solutions to mixed aqueous solutions of manganese and nickel salts, mixing said composite hydroxides with a lithium compound burning said mixture to make positive active materials, forming a paste containing said positive active materials and coating said paste on aluminum foils constituting the positive electrodes of the batteries.