Effect of synthesizing temperature on the electrochemical properties of nitrogen-doped Co-B alloys

Using urea as nitrogen source, nitrogen-doped Co-B alloys were prepared by chemical reduction method at different reaction temperatures (25, 50, and 75 ?C). The structure and surface morphology were characterized by XRD and SEM. Then they were used as negative electrode materials for alkaline secondary batteries (ASBs). The electrochemical properties were measured by galvanostatic charge-discharge, electrochemical impedance spectroscopy (EIS), and anodic polarization (AP). The experimental results show that the lower the synthesizing temperature is, the better the electrochemical performance of nitrogen-doped Co-B alloy is. For example, nitrogen-doped CoB alloy prepared at 25 ?C has an initial discharge capacity of 825.8 mAh/g. After 100 charge/discharge cycles, the discharge specific capacity has remained to be 369.5 mAh/g with capacity retention of 44.7%.