Abstract: Hydrogen storage alloy powder, an anode, and a nickel-hydrogen rechargeable battery are provided, which are excellent in low-temperature characteristics and both in initial activity and cycle life at the same time, which properties are trading-off in conventional nickel-hydrogen rechargeable batteries. The alloy powder has a composition represented by formula (1) R1-aMgaNibAlcMd (R: rare earth elements including Sc and Y, or the like; 0.005?a?0.40, 3.00?b?4.50, 0?c?0.50, 0?d?1.00, 3.00?b+c+d?4.50), and has an arithmetical mean roughness (Ra) of the powder particle outer surface of not less than 2 ?m, or a crushing strength of not higher than 35,000 gf/mm2.

Abstract: 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), R1-aMgaNibAlcMd, 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.

Abstract: Hydrogen storage alloy powder, an anode, and a nickel-hydrogen rechargeable battery are provided, which are excellent in low-temperature characteristics and both in initial activity and cycle life at the same time, which properties are trading-off in conventional nickel-hydrogen rechargeable batteries. The alloy powder has a composition represented by formula (1) R1-aMgaNibAlcMd (R: rare earth elements including Sc and Y, or the like; 0.005?a?0.40, 3.00?b?4.50, 0?c?0.50, 0?d?1.00, 3.00?b+c+d?4.50), and has an arithmetical mean roughness (Ra) of the powder particle outer surface of not less than 2 ?m, or a crushing strength of not higher than 35,000 gf/mm2.

Abstract: 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), R1-aMgaNibAlcMd, 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.