DECAY IN THE HYDROGEN STORAGE CAPACITY OF A LANI4.7AL0.3 ALLOY POWDERWITH EXPOSURE TO AIR AND WITH HYDRIDING-DEHYDRIDING CYCLES

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