Effects of metallic cobalt addition on the performance of pasted nickel electrodes

A study is made on the performance of Ni-foam pasted nickel electrodes prepared from co-precipitated Ni1−xZnx(OH)2 with and without cobalt powder. The addition of cobalt provides higher performance in terms of both discharge capacity and cycle life. Cobalt increases remarkably the active-material utilization through enhancement of the discharge depth due to the formation of conducting CoOOH during the first activation charging. The superior capacity stability during cycling is attributed to the synergistic action of zinc and cobalt, especially to the co-precipitation of zinc hydroxide which is considered to inhibit the formation of γ-NiOOH.