HYDROGEN STORAGE ALLOY POWDER, METHOD FOR MODIFYING HYDROGEN STORAGE ALLOY, SECONDARY BATTERY, HYBRID CAR, AND ELECTRIC VEHICLE

摘要

PROBLEM TO BE SOLVED: To produce hydrogen storage alloy powder having superior corrosion resistance to electrolytic solution, to provide a method for modifying the hydrogen storage alloy powder by which corrosion resistance to electrolytic solution can be improved without causing adverse effects, and a secondary battery which has a cathode containing the hydrogen storage alloy powder and has improved charge/discharge cycling. SOLUTION: In the hydrogen storage alloy, at least one compound selected from the group consisting of the sulfides of metallic elements and the hydrosulfides of metallic elements is present at least on a part of the surface of powder particles or the alloy powder is immersed in an aqueous solution of >=pH 11 in which at least one compound selected from the group consisting of the alkali metal salts of orthophosphoric acid, the sulfides of alkali metals and the polysulfides of alkali metals is dissolved and then the alloy powder is dried.