Mechanical alloying preparation of fullerene-like Co3C nanoparticles with high hydrogen storage ability

Fullerene-like orthorhombic-structured Co3C nanoparticles have been synthesized by direct ball-milling of Co and graphene (GE) powders with different Co/GE weight ratios. Electrochemical measurements showed that the Co3C nanoparticles displayed excellent electrochemical hydrogen storage capacities and the maximum capacity reached 1415 mA h/g (5.176 wt% hydrogen) at room temperature and ambient pressure. The reaction mechanism and the reasons for the differences of the Co3C electrodes were also investigated. It was found that the quasi-reversible Co3CHx/Co3C reaction was dominant for all the Co3C electrodes.

► A series of Co3C nanoparticles have been synthesized by direct ball-milling.
► The maximum capacity reached 1415 mA h/g (5.176 wt% hydrogen) at ambient atmosphere.
► The reaction mechanism and the reasons were investigated.
► It is first report for the practical applications (>5 wt%) at ambient atmosphere.