High energy ball-milling preparation of Co–B amorphous alloy with high electrochemical hydrogen storage ability

Abstract

As a new type hydrogen storage material, Co–B hydrogen storage alloy was a hot research topic and has been paid increasing attention in recent years. In this work, a series of Co–B alloys with molar ratio of 1:1, 2:1 and 3:1 were synthesized by high energy ball-milling method. The phase, structure and morphology of the samples have been characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM), which demonstrated that the samples ball-milled more than 5h were mainly amorphous phase. Their electrochemical performance as electrochemical hydrogen storage material was investigated by galvanostatic charge–discharge process and cyclic voltammetry (CV) techniques. Electrochemical measurements showed that the Co–B alloys had excellent electrochemical hydrogen storage capacities and exhibited remarkable high rate discharge performance. Their electrochemical hydrogen storage capacity was 771mAh/g, which was much higher than previous reports (238mAh/g). Based on XRD and CV results, the exceptional electrochemical performances were suggested to arise from the electrochemical hydrogen storage reaction on the Co–B materials, which was brought about by the special amorphous structure and high chemical reactivity of the Co–B particles.