PURPOSE: To obtain a hydrogen storage alloy particle, which gives a nickel- hydrogen accumulator excellent in cycle life, high rate discharge characteristic, high temp. discharge preservation characteristic, initial activity and boosting charge characteristic.
CONSTITUTION: The hydrogen storage alloy particle is obtained by forming a porous or dotted coating film, which is selected from a group composed of cobalt, tin, copper, nickel, lanthanum oxide and a fluorine based compound, directly on the surface of the particle without intermediary of an oxide film. The producing method of the hydrogen storage alloy involves a process of removing a surface oxide film by dipping a mechanically pulverized hydrogen storage alloy particle into hydrofluoric acid or a mixed acid of hydrofluoric acid with nitric acid and a process of forming the coating film on the surface of the hydrogen storage alloy particle after washing by adding an aq. solution containing a metallic ion selected from the group composed of cobalt, tin, copper, nickel and lanthanum without allowing the hydrogen storage alloy particle to contact with air, washing and drying to form the coating film on the surface of the hydrogen storage alloy particle.
SERI HAJIME
TSUJI YOICHIRO
TOYOGUCHI YOSHINORI
