The invention discloses
rare earth-
magnesium-
nickel system heterogeneous
hydrogen storage alloys used for
nickel-
hydrogen batteries and a preparing method thereof. The alloys are characterized in that: the general structure formula of the alloys is LnMgNi<x>Y<y>Z<z>, wherein the Ln is at least one element selected from
rare earth elements; the Y is at least one element selected from a group comprising Co, Mn, Al, Cu, Nb, V, Fe, Zn, Ti, Cr, As, Ga, Mo, Sn, In, W, Si, B and P; the Z is at least one element selected from a group comprising Ag, Sr, Ge and Au; the a is less than 1 and not less than 0.5; the b is less than 0.5 and more than 0; the x is more than 2.5 and less than 4.5; the y is more than 0 and less than 2; the z is more than 0 and not more than 1; an AB5 phase accounts for 10-90%; an A2B7 phase accounts for 10-90%; and the ratio of other
impurity phases is not more than 30%. B side elements are replaced by the Ag, the Sr, the Ge, the Au, and the like,
alloy components and an annealing process are optimized, and the ratio of the AB5 phase to the A2B7 phase in the product is adjusted, thus increasing the
discharge capacity of the
hydrogen storage
alloy, prolonging the cycle lifetime of the
hydrogen storage alloy, and improving self-
discharge and low-temperature properties.