Preparation and Study on Electrochemical Characteristics of Mg_2Ni System Hydrogen Storage Alloy

摘要

Mg_2Ni system hydrogen storage alloy with amorphous structure was prepared by solid state-diffusion and mechanical grinding. X-ray diffraction profiles indicate that with the increasing grinding time, the diffraction peak broadening becomes more serious due to occurrence of defects and strains in the alloys, and it remains almost constant after grinding times longer than 12h. The effect of partial substitution of Al for Mg on the electrochemical properties of Mg_2Ni was investigated. The results show that Mg_2. _xAl_xNi (x=0.2, 0.3) has the longest cycle life, up to 50 cycle numbers at 200mA/g discharge current density when x=0.2. It was found that the effect of Al prolonging Mg_2Ni cycle life was possibly ascribed to the existence of A1_2O_3 film on the surface of alloy.