Gas atomization of metal hydrides for Ni-MH battery applications

The use of high Pressure gas atomization (HPGA) to produce fine, spherical powders of metal hydride (MH) alloys has been shown to improve the properties of the alloy, as well as reducing costly processing steps. Electrochemical cycling was used to compare three electrodes constructed of LaNi4.75Sn0.25 particulate, a simplified AB(5)-type alloy for battery applications. Two electrodes consisted of gas atomized powders and the other used particulate produced from casting and crushing an ingot, the conventional method of MH particulate production. Gas atomized powders showed improved cyclic stability over the cast and crushed particulate. A commercial cast and crushed MmNi(3.55)Co(0.75)Mn(0.4)Al(0.3), alloy was also cycled and showed reduced degradation when compared against the electrode composed of LaNi4.75Sn0.25 cast and crushed particulate, as was expected. (C) 2000 Elsevier Science B.V. All rights reserved.