The application of mathematical models to the calculation of selected hydrogen storage properties (formation enthalpy and hysteresis) of AB2-type alloys

Two mathematical models have been applied to AB(2)-type hydrogen-absorbing alloys. The first model is for the calculation of hydride formation enthalpy and the second model allows for the calculation of P-C-T curves. Certain physical parameters (activity coefficient of hydrogen (gamma), partial molar volume of hydrogen ((V) over bar(H)), solution heat of hydrogen (Delta H-s), enthalpy (Delta H) and entropy (Delta S) of formation of a hydride, slope factor (f(s)) of a plateau and the variation rate (k) of slope factor with respect to temperature in a plateau region of P-C-T curves) for these intermetallic compounds and their hydrides are estimated from these models. From the second model, the relationship between the hysteresis factor (RT ln P-a/P-d) and temperature, hydrogen concentration and slope factor of the plateau region for the P-C-T curves has been obtained. (C) 1999 International Association for Hydrogen Energy. published by Elsevier Science Ltd. All rights reserved.