Hydrogen storage alloy, hydrogen storage alloy electrode and nickel metal hydride secondary battery using the hydrogen storage alloy

A hydrogen storage alloy electrode comprising:

• a core member having conductivity;
• and
• a particle that is made of hydrogen storage alloy carried by the core member, wherein
• the particle has a composition expressed by a general formula:
• (LaaSmbGdc“A”d)1-wMgwNixAly“T”z
• where “A” represents at least one element selected from a group consisting of Pr, Nd, Eu, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sc, Zr, Hf, Ca and Y;
• “T” represents at least one element selected from a group consisting of V, Nb, Ta, Cr, Mo, Mn, Fe, Co, Ga, Zn, Sn, In, Cu, Si, P and B;
• subscripts a, b, c and d satisfy relationship expressed by a>0, b≧0, c>0, 0.1>d≧0, and a+b+c+d=1;
• and
• subscripts w, x, y and z fall within a range shown by 0.1≦w≦0.3, 0.05≦y≦0.35, 0≦z≦0.5, and 3.2≦x+y+z≦3.8.

A nickel metal hydride secondary battery comprising:

• a hydrogen storage alloy electrode as a negative electrode;
• a positive electrode;
• and
• an alkaline electrolyte, wherein
• the hydrogen storage alloy electrode includes:
• a core member having conductivity;
• and
• a particle that is made of hydrogen storage alloy carried by the core member, wherein
• the hydrogen storage alloy has a composition expressed by a general formula:
• (LaaSmbGdc“A”d)1-wMgwNixAly“T”z
• where “A” represents at least one element selected from a group consisting of Pr, Nd, Eu, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sc, Zr, Hf, Ca and Y;
• “T” represents at least one element selected from a group consisting of V, Nb, Ta, Cr, Mo, Mn, Fe, Co, Ga, Zn, Sn, In, Cu, Si, P and B;
• subscripts a, b, c and d satisfy relationship expressed by a>0, b≧0, c>0, 0.1>d≧0, and a+b+c+d=1;
• and
• subscripts w, x, y and z fall within a range shown by 0.1≦w≦0.3, 0.05≦y≦0.35, 0≦z≦0.5, and 3.2≦x+y+z≦3.8.