| 摘要 |
PROBLEM TO BE SOLVED: To increase the utilization factor at a high temperature while maintaining the battery performance of a nickel positive electrode by applying a single substance or a compound of rare earth elements on the surface of the nickel electrode mainly made of nickel hydroxide. SOLUTION: A single substance or a compound of rare earth elements is slightly dissolved in an alkaline aqueous solution and deposited as a stable hydroxide. This hydroxide has an effect to raise the oxygen overvoltage at a high temperature, the generation of oxygen gas from the positive electrode side at the terminal stage of an electric charge is suppressed, and the utilization factor at a high temperature can be increased. When a single substance or a compound of rare earth elements is added, a film is formed when the rare earth element ions slightly eluted in an electrolyte are deposited on the surface of a hydrogen storage alloy electrode as a stable hydroxide, and the battery life is extended because the film prevents the corrosion of the alloy. This action is prominent in particular for ytterbium which is one of the rare earth elements. |
