Rehydrogenation and cycle studies of LiBH4-CaH2 composite

Abstract

Rehydrogenation behavior of 6LiBH(4) + CaH2 composite with NbF5 has been studied between 350 and 500 degrees C after dehydrogenation at 450 degrees C. The composite exhibits the best rehydrogenation feature at 450 degrees C in terms of the overall rehydrogenation rate and the amount of absorbed hydrogen. It is found that about 9 wt% hydrogen is absorbed at 450 degrees C for 12 h. Up to 10 dehydrogenation-hydrogenation cycles have been carried out for the composite. It is demonstrated that 6LiBH(4) + CaH2 with 15 wt% NbF5 maintains a reversible hydrogen storage capacity of about 6 wt% at 450 degrees C after a slight degradation between the 1st and 5th cycles. The addition of NbF5 seems to improve the cycle properties by retarding microstructural coarsening during cycles. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.