HYDROGEN-ABSORBING ALLOY POWDER, NEGATIVE ELECTRODE, AND NICKEL HYDROGEN SECONDARY BATTERY

Provided are hydrogen storage alloy powder capable of providing a nickel-hydrogen rechargeable battery with simultaneous excellence in initial activity, discharge capacity, and cycle characteristics, which are otherwise in a trade-off relationship, an anode for a nickel-hydrogen rechargeable battery as well as a nickel-hydrogen rechargeable battery employing the same. The hydrogen storage alloy has a particular composition represented by formula (1), RMgNiAlM, and has at its outermost surface a Mg-rich/Ni-poor region having a composition with a Mg molar ratio higher than that in formula (1) and a Ni molar ratio lower than that in formula (1), and has inside a Mg/Ni-containing region having a composition with a Mg molar ratio lower than and a Ni molar ratio higher than those in the Mg-rich/Ni-poor region.