Sorption properties of Mg-Ni-CrCl_3 hydrogen storage composite

摘要

Hydrogen absorption composite powder of Mg incorporated with Ni and CrCl3 （88∶10∶2 in mass ratio） was prepared by reactive milling in hydrogen atmosphere. Hydriding/dehydriding performances were measured by self-made apparatus. The results show that reactive milling and multi-component addition of Ni and CrCl3 reduce the stability of hydride and improve the sorption performance of Mg-based materials. With powder milled for 60h, hydriding basically completes within 300s （250℃, 2.0MPa） and phase transformation fraction reaches 0.78. The phase transformation rate of hydriding/dehydriding progress increases significantly with the reduced particles size of powder while good kinetics of dehydriding at a relatively low temperature is gained with small grain size of hydride. Rapid temperature variations in a short span of time resulted from remarkable calorific effects of rapid phase transformation are detected in hydriding/dehydriding progress. The results of thermogravimetric and differential scanning calorimetric（TG/DSC） indicate that the onset temperature of desorption of composite milled for 100h is 272℃.