Facile synthesis of Mo-Ni particles and their effect on the electrochemical kinetic properties of La-Mg-Ni-based alloy electrodes

A simple method was developed to synthesize Mo-Ni compounds using a chemical reduction method. The compound was then added to La-Mg-Ni-based alloy electrodes in order to improve the electrochemical kinetics of the electrodes. Scanning electron microscopy and transmission electron microscopy coupled with energy-dispersive X-ray spectroscopy showed that the as-synthesized compound consisted of nanoparticles with a chemical composition of MoNi2.5. X-ray diffraction analysis revealed that the compound mainly consisted of a MoNi3 and a Ni phase. The Mo-Ni particles were added to the La-Mg-Ni-based alloy electrode material and uniformly distributed on the alloy surface. An improvement in initial discharge capacity and high rate dischargeability (HRD) could be observed, as well as an enhancement of cycle stability. At 1500 mA/g the HRD increased by 10.2%, and the initial discharge capacity increased from 286 mA h/g to 307 mA h/g. After adding the particles to the alloy, the Mo-Ni particles showed a high electro-catalytic activity due to a charge transfer reaction on the alloy surface, thereby decreasing the charge transfer resistance and increasing the exchange current density. Consequently, the kinetics of the electrode reaction was significantly improved due to an enhancement of the electro-catalytic activity.