Kinetics of absorption and desorption of hydrogen in alloy powder

A new model for predicting the reacted fraction of hydriding/dehydriding (H/D) in powder hydrogen storage materials has been developed, which offers an analytic form expressing the reacted fraction of hydrogen absorption/desorption (A/D) as a function of time, temperature and pressure explicitly. Therefore it is simple and practical. Besides, an important new concept, so called the characteristic absorption/desorption time has been introduced that greatly simplifies the formulae and offers some sigificant physical meaning that might be useful for theoretical discussion in future. The application of this new model to Mg1.95Ag0.05Ni and LaNiMg17 alloys indicates that this new model works very well. (C) 2004 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.