The effects of Ba(OH)(2) and Co(OH)(2) on electrochemical performance of nickel hydroxide prepared with chemically co-precipitated zinc in a nickel-metal hydride battery (Ni-MH) are studied. The results show that the oxygen-generation potential and the discharge depth of the nickel electrode are improved by the combined addition of Ba(OH)(2) and Co(OH)(2) compared with only Co(OH)(2). The capacity of the Ni-MH battery is also enhanced due to increase in the utilization of the active material of the positive electrode.