Active material for a negative electrode of a nickel-metal hydride alkaline accumulator

摘要

Hydridable alloy comprising metal complex (I), is claimed. Hydridable alloy comprising metal complex of formula (R 1 - x - yMg xM yNi s - aB2 a), where: at least 5 vol.% of which consists of a stack of sequences with a pattern of the A 2B1 4type and n patterns of calcium copper (CaCu 5) type randomly distributed along one direction, n is an integer comprised of 1-10 and representing the number of patterns of the CaCu 5type per pattern of the A 2B1 4type; A is one or more elements forming stable hydrides under normal conditions of temperature and of pressure, for e.g. rare earths; and B1 is one or more elements, for which the hydrides are unstable under the same conditions, e.g. nickel, is claimed. R : group of rare earths and/or yttrium; M : Zr and/or Ti; B2 : Mn, Al, Co and/or Fe; x : 0.1-0.4; y : 0-0.1; s : 3-4.5; and a : 0-1. Independent claims are included for: (1) a method for making (I) comprising: (a) mixing magnesium-nickel (Mg 2Ni) with a compound comprising (i) nickel, (ii) one or several elements comprising rare earths and yttrium, with optionally titanium and/or zirconium and (iii) optionally an element comprising manganese, aluminum, cobalt and/or iron, (b) milling the mixture, and (c) sintering the mixture by compressing the mixture and applying current through the mixture; (2) a negative electrode of an alkaline accumulator of the nickel metal hydride type, comprising (I); and (3) an alkaline accumulator of the nickel metal hydride type comprising the electrode.