JP2794825B

PURPOSE:To obtain a nickel hydroxide electrode of high utilization factor even by the use of metallic cobalt having an oxide film thereon by applying a voltage less than electric potential for dissolution/deposition of metal cobalt, and then charging a battery. CONSTITUTION:During formation of a nickel hydroxide electrode, a voltage less than electric potential for dissolution/deposition of metal cobalt is applied to the electrode and then a battery is charged. A passive film formed on the surface of metal cobalt is readily removed by application of a voltage less than electric potential for dissolution/deposition of metal cobalt i.e., to a mercury oxide electrode, and the same effect as when using metal cobalt with no oxide film can be obtained and so the metal cobalt covered with the passive film is totally charged and an electrode of large discharge capacity and which has no dispersion is obtained. Thus metal cobalt having its surface oxidized is usable and an electrode of large discharge capacity and which has no dispersion is obtained.