Surface treatment method of hydrogen storage alloy for alkaline secondary battery and alkaline secondary battery equipped with hydrogen storage alloy subjected to the surface treatment as electrode

摘要

PURPOSE:To prevent the initial activation and conductivity lowering due to the deposition of an excess oxide on the alloy surface, to produce a hydrogen storage alloy excellent in the charge and discharge characteristic and cycle life characteristic with high productivity and to provide a secondary battery having a surface-treated electrode in the surface treatment of a hydrogen storage alloy to be used as the cathode of a nickel-hydrogen battery to improve its alkali resistance. CONSTITUTION:A hydrogen storage alloy is produced, the alloy is crushed in the first step, the crushed alloy is treated with an aq. alkali in the second step, the treated alloy is treated with an aq. soln. of a chelating chemical in the third step, the chelated alloy is washed with water in the fourth step, and the alloy is surface-treated. Consequently, the hydrogen storage alloy powder and electrode excellent in alkali resistance, initial activation and cycle life characteristic is obtained.