Hydrogen Storage Performance of Mechanical Mg2Ni Alloy Evaluated With A High-Pressure Microbalance

Mechanical ball-milling was used to prepare Mg2Ni alloy powder. Effects of milling time (5-20 h) on the crystal structure and morphology were studied with an X-ray diffractometer (XRD) and a scanning electron microscope (SEM), respectively. The hydrogenation properties, which included storage capacity and absorption rate, of the prepared alloys were evaluated using a microbalance under a hydrogen pressure of 20 bar at 573 K. The experimental results indicated that prolonging the milling time caused the reduction both in the particle size and crystal size of the synthesized Mg2Ni alloy powder, and thus improve the hydrogen uptake performance. The optimum hydrogen storage capacity found in this study was 2.89 wt% for the 20 h ball-milled Mg2Ni alloy powder. A complete phase transformation from Mg2Ni to Mg2NiH4 upon hydrogenation was recognized.