JP2004124132A5 - - Google Patents

Claims (7)

A lanthanoid having a CaCu ₅ type crystal structure, La, Ce, Y and at least one element among lanthanoids having an atomic number of 63 or more, Ni and Co as essential components, and R1 among lanthanoids having an atomic number of 59 to 62 R2 is Y and at least one element of lanthanoids having an atomic number of 63 or more, X is at least one metal element not belonging to the rare earth, and the composition formula La _a Ce _b R1 _c R2 when expressed in _d Ni _e Co _f X _g, the a + b + c + d = a 1.0, 0.6 ≦ a ≦ 0.9,0.05 ≦ b, 0 ≦ c, 0 <d ≦ 0.06 A hydrogen storage alloy powder, wherein 5.0 ≦ e + f + g ≦ 5.4, 0.1 ≦ f ≦ 1.2, and 0 <g. In the hydrogen storage alloy of claim 1, further comprising a Mg as an essential component, when expressed by the composition formula _{La a Ce b R1 c R2 d} Mg h Ni e Co f X g, be the a + b + c + d + h = 1.0 0.6 ≦ a ≦ 0.9, 0.05 ≦ b, 0 ≦ c, 0 <h <0.04, 0 <d ≦ 0.06, 5.0 ≦ e + f + g ≦ 5.4, 0 The hydrogen storage alloy powder according to claim 1, wherein 1 ≦ f ≦ 1.2 and 0 <g. The composition formula _{La a Ce b R1 c R2 d} Ni e Co f X g and _{La a Ce b R1 c R2 d} Mg h Ni e Co f X g of the metal element X is Mn, Al, of Fe, at least one The hydrogen storage alloy powder according to claim 1 or 2, wherein the hydrogen storage alloy powder is the element.   A hydrogen storage alloy powder having the composition according to claim 1 or 2, wherein R2 contained in the powder (R2 represents at least one element of Y and an lanthanoid having an atomic number of 63 or more) The hydrogen storage alloy powder is characterized in that the concentration of) is higher on the surface of the powder than in the powder.   A hydrogen storage alloy electrode, wherein the hydrogen storage alloy powder according to claim 1, 2, 3, or 4 is supported on a substrate made of an alkali electrolyte resistant metal.   A nickel-metal hydride storage battery having a nickel electrode as a positive electrode and the hydrogen storage alloy electrode according to claim 5 as a negative electrode.   The nickel-metal hydride storage battery according to claim 6, wherein the nickel electrode contains at least one element of Er, Tm, Yb, Lu, and Y.