Hydrogen absorption and electrochemical properties of Mg2Ni-type alloys synthesized by mechanical alloying

Mg2Ni-type alloys, i.e., Mg2Ni, Mg2Ni0.75Cu0.25, Mg2Ni0.6Cu0.4 and Mg2Ni0.75V0.25 were synthesized by mechanical alloying and subsequent thermal treatment starting from a corresponding elemental powder mixture. The kinetics of hydrogen absorption and desorption of annealed materials were measured using a manually controlled Sieverts apparatus. The electrochemical characteristics of Mg2Ni-type alloys were tested for their ability to store hydrogen at room temperature by using constant current to charge and discharge the electrode. The partial substitutions of Cu and V for Ni increased hydrogen absorption and desorption at 200 °C and improved the electrochemical storage capacity and cycle life at room temperature.