| 摘要 |
PURPOSE:To stabilize and enhance the utilization factor of active material and also enhance productivity by adding to the active material a kind of cobalt having a valence of two or less and a high-order cobalt oxide having a valence of three or more. CONSTITUTION:In a non-sintered type positive electrode plate in which an active material composed mainly of nickel hydroxide is held on an alkali resistant conductive material, a kind of cobalt having a valence of two or less and a high-order cobalt oxide having a valence of three or more are added to the active material. The high- order cobalt oxide having a valence of more than three is desirably obtained by heating of cobalt hydroxide at temperatures above 60 deg.C in the presence of an alkali solution. Cobalt hydroxide from which a kind of cobalt having a valence of two or less is generated by means of a dissolution-deposition reaction is converted to cobalt oxyhydroxide through anodic oxidation within the range of the potential of a positive electrode plate. The potential of the electrode is held within the range of the anodic oxidation of the cobalt and the competitive reaction of the cobalt and nickel hydroxide does not occur, so the reaction progresses more effectively and a sufficient layer of cobalt oxyhydroxide is formed, thereby enhancing the utilization factor of the active material. |
