Decay in the hydrogen storage capacity of a LaNi4.7Al0.3 alloy powder with exposure to air and with hydriding-dehydriding cycles

The hydrogen storage capacity of an air-exposed LaNi4.7Al0.3 alloy powder was investigated using hydrogen absorption/desorption experiments. The LaNi4.7Al0.3 alloy powder was first exposed in air for up to 90 days producing an oxidized surface layer which was about 50 nm in depth of the grain particle surface. The hydrogen storage capacity decreased with increasing exposure to air. However the slope of the P-C-T plateau remained approximately constant for the different exposure times. (C) 1997 International Association for Hydrogen Energy. All rights reserved.