THE TEMPERATURE-DEPENDENCE OF HYDROGEN SORPTION IN METAL-HYDRIDES

Down to temperatures about - 100-degrees-C and lower the sorption kinetic and the diffusion rate of the Ti-Zr Laves phase hydride investigated here are very high. For this reason and because of the sorption enthalpy of about 25 kJ mol-1 it is difficult to establish isothermal measurement conditions. The result is a thermal ignition. With a very simple thermal ignition model based on an energy balance and first order kinetic the measurements at temperatures down to - 196-degrees-C are explained. The kinetic parameters taken for calculating the ignition model have previously been published by Bernauer et al. in this journal. The experimental and theoretical results presented here ensure that the sorption model previously presented is usable for hydride storage systems filled with such fast reacting hydrides.