Electrochemical and Gas-Solid Hydrogen Storage Properties of a Multi-Metal Magnesium-Based Alloy Obtained by Ball Milling

The hydrogen sorption and electrochemical properties of the alloy Mg50Ni12.5Al12.5V12.5Fe12.5 synthesized by ball milling under the protected atmosphere of argon for 50 h in a planetary ball mill are investigated. The significantly fast rate of absorption reaction is observed along with the hydrogen absorption capacity of 2.04 wt.% H2 at temperatures 200 and 300 degrees C and at a pressure of 1 MPa. Even at room temperature, the absorption capacity is relatively high, and it is about 1.6 wt.% H2. The alloy ball milled for 50 h and the alloy after cycling and hydrogenation were characterized by X-ray diffraction analyses, SEM, and TEM. The prepared alloy was tested as an anode in a Ni/MH battery in a 6 M KOH electrolyte. Galvanostatic and potentiostatic discharge modes were employed, revealing activation after the third cycle and giving a discharge capacity of 257 mAh/g.