An electrode plate is made by loading a supporting porous metallic plaque with active battery material made by: (1) hydrolyzing the reaction product of a starting material comprising an admixture of Ni oxide and effective amounts of sodium peroxide fused at temperatures between about 800.degree.-1150.degree. C, the hydrolyzed solid reaction product containing electrochemically active Ni hydrated oxides and hydroxide forms, (2) if desirable, drying the product below about 65.degree. C, and (3) adding, at some step in the method, an amount of cobalt containing additive effective to provide about 2-12 wt% total Co in the active battery material based on Ni oxide plus Co content.