Synthesis and properties of the Mg2Ni0.5Co0.5H4.4 hydride

• Preparation of the Mg2Ni0.5Co0.5H4.4 hydride by reactive ball milling.
• Crystal structure determination by X-ray powder diffraction.
• Electrochemical studies of the ball milled MH/Ni electrodes.

The Mg2Ni0.5Co0.5H4.4 hydride with a grain size of 16 nm was prepared by reactive ball milling. Its crystal structure was studied by X-ray powder diffraction. A tetragonal Mg2CoH5 structure type was suggested for the obtained hydride. The decomposition temperature of the Mg2Ni0.5Co0.5H4.4 phase was observed at 213 °C. Electrochemical measurements as negative electrode of Ni–MH battery were also performed. Significant improvements can be made by ball-milling the hydride with nickel powder.

Crystal structure of the Mg2Ni0.5Co0.5H4.4 hydride.Figure optionsDownload as PowerPoint slide