Structure and electrochemical hydrogen storage behaviors of alloy Co2B

The alloys Co2B were prepared by two ways of high temperature solid phase process and arc melting, the structure of the alloys was characterized by XRD and SEM. It showed that it was structure of tetragonal Co2B.The electrochemical experimental results demonstrated that the Co2B prepared by two means both showed excellent cycling stability. The initial discharge capacity of Co2B prepared by the high temperature solid phase process was 480.3 mA h g−1, there was no distinct declination after 70 charge–discharge cycles and the capacity kept about 195 mA h g−1. Co2B prepared by the high temperature solid phase process showed very good electrochemical reversibility in CV curves. The hydrogen storage mechanism was also discussed, it confirmed that the high initial capacity of Co2B prepared by the high temperature solid phase process was due to the oxidation of Co and B2O3, and it was irreversible.