Nickel-metal hydride storage battery and alloy for configuring negative electrode of the same

A hydrogen storage alloy for a battery which comprises an intermetallic compound having a composition represented by the general formula Zr.sub.1-x M.sup.3.sub.x Mn.sub.a Mo.sub.b Cr.sub.c M.sup.1.sub.d M.sup.2.sub.e Ni.sub.f, where M.sup.1 represents at least one element selected from the group consisting of V, Nb and rare earth elements, M.sup.2 represents at least one element selected from the group consisting of Fe, Co and Cu, and M.sup.3 represents at least one element selected from the group consisting of Ti and Hf, and where 0.ltoreq.x.ltoreq.0.3, 0.3.ltoreq.a.ltoreq.0.7, 0.01.ltoreq.b.ltoreq.0.2, 0.05.ltoreq.c.ltoreq.0<d.ltoreq.0.1, 0.ltoreq.e.ltoreq.0.2, 0.8.ltoreq.f.ltoreq.1.3, and 1.6.ltoreq.a+b+c+d+e+f.ltoreq.2.2, and

• wherein said hydrogen storage alloy has at least one of a Laves phase having a crystal structure of the MgCu.sub.2 -type (C15) and a Laves phase having a crystal structure of the MgZn.sub.2 -type (C14), and wherein a sum of integrated intensities of diffraction peaks other than those attributed to the presence of said Laves phase is not more than 5% of a sum of integrated intensities of all diffraction peaks in a diffraction angle 2.theta. of 10.degree. to 80.degree. in a powder X-ray diffraction pattern by Cu K.alpha. radiation.

A hydrogen storage alloy for a battery which comprises an intermetallic compound having a composition represented by the general formula Zr.sub.1-x Ti.sub.x Mn.sub.a Mo.sub.b Cr.sub.c V.sub.d Co.sub.e Ni.sub.f, where 0.15.ltoreq.x.ltoreq.0.25, 0.4.ltoreq.a.ltoreq.0.6, 0.01.ltoreq.b.ltoreq.0.2, 0.15.ltoreq.c.ltoreq.0.25, 0<d.ltoreq.0.1, 0.ltoreq.e.ltoreq.0.2, 1.ltoreq.f.ltoreq.1.3, and 1.6.ltoreq.(a+b+c+d+e+f).ltoreq.2, and

• wherein said hydrogen storage alloy has at least one of a Laves phase having a crystal structure of the MgCu.sub.2 -type (C15) and a Laves phase having a crystal structure of the MgZn.sub.2 -type (C14), and wherein a sum of integrated intensities of diffraction peaks other than those attributed to the presence of said Laves phase is not more than 5% of a sum of integrated intensities of all diffraction peaks in a diffraction angle 2.theta. of 10.degree. to 80.degree. in a powder X-ray diffraction pattern by Cu K.alpha. radiation.

A hydrogen storage alloy for a battery which comprises an intermetallic compound having a composition represented by the general formula ZrMn.sub.a Mo.sub.b Cr.sub.c M.sup.1.sub.d M.sup.2.sub.e Ni.sub.f, where M.sup.1 represents at least one element selected from the group consisting of V, Nb and rare earth elements, and M.sup.2 represents at least one element selected from the group consisting of Fe, Co and Cu, and where 0.4.ltoreq.a.ltoreq.0.7, 0.1.ltoreq.b.ltoreq.0.2, 0.1.ltoreq.c.ltoreq.0.3, 0<d.ltoreq.0.1, 0.ltoreq.e.ltoreq.0.2, 1.0.ltoreq.f.ltoreq.1.3, and 1.8.ltoreq.a+b+c+d+e+f.ltoreq.2.2, and

• wherein said hydrogen storage alloy has at least one of a Laves phase having a crystal structure of the MgCu.sub.2 -type (C15) and a Laves phase having a crystal structure of the MgZn.sub.2 -type (C14), and wherein a sum of integrated intensities of diffraction peaks other than those attributed to the presence of said Laves phase is not more than 5% of a sum of integrated intensities of all diffraction peaks in a diffraction angle 2.theta. of 10.degree. to 80.degree. in a powder X-ray diffraction pattern by Cu K.alpha. radiation.