POWDER MATERIAL, ELECTRODE STRUCTURE, MANUFACTURE OF THEM, AND SECONDARY BATTERY

• Main Author: KAWAKAMI SOICHIRO
• Format: Patent
• Language: English
• Published: 13.10.1998
• Edition: 6
• Subjects: ALLOYS; BASIC ELECTRIC ELEMENTS; CASTING; CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS ANDNON-FERROUS ALLOYS; CHEMICAL SURFACE TREATMENT; CHEMISTRY; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY IONIMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING MATERIAL WITH METALLIC MATERIAL; COATING METALLIC MATERIAL; COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSESC01D OR C01F; DIFFUSION TREATMENT OF METALLIC MATERIAL; ELECTRICITY; FERROUS OR NON-FERROUS ALLOYS; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; INORGANIC CHEMISTRY; MAKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; METALLURGY; PERFORMING OPERATIONS; POWDER METALLURGY; PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSIONOF CHEMICAL INTO ELECTRICAL ENERGY; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THESURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; TRANSPORTING; TREATMENT OF ALLOYS OR NON-FERROUS METALS; WORKING METALLIC POWDER

PROBLEM TO BE SOLVED: To enhance overcharging resistance and charge/discharge efficiency by using a powder material prepared by forming a metal oxide having oxidation resistance on a core layer mainly comprising a hydrogen storage alloy, and forming the dispersion layer of a metal element for activating hydrogen on the metal oxide in a negative electrode. SOLUTION: Hydrogen storage compound powder 104 is formed by covering a core layer 101 made of a hydrogen storage alloy with a transition metal oxide 102 so as to carry a transition metal element on the surface. In a secondary battery using the hydrogen storage compound powder 104 as a negative active material and nickel hydroxide as a positive active material, hydrogen generated in a negative electrode during charge is adsorbed by the transition metal 103 carried on the outermost surface, and an active, atom-state hydrogen is efficiently generated. The active, atom-state hydrogen passes through the transition metal oxide 102, and is stored in the hydrogen storage alloy 101 in the core layer. In the overcharge, the transition metal oxide 102 suppresses oxidation of the hydrogen storage alloy 101 by excess oxygen gas generating in a positive electrode.