Effect of ball-milling time and Pd addition on electrochemical hydrogen storage performance of Co2B alloy

The Co 2 B alloy is synthesized by high temperature solid phase process. 5 wt% Pd is added to the Co 2 B alloy by ball milling at different milling time in order to enhance discharge performance of the raw alloy. The phase structure and surface morphology of these alloys is characterized by XRD and SEM. The discharge capacities of the alloy milled for 10 min and 30 min are higher than that of the raw alloy. However, the discharge capacity of the alloy milled for 1 h is lower than that of the raw alloy. The result of linear polarization and EIS shows that proper milling time and uniform distribution of palladium on the alloy surface can make the alloy electrode have excellent discharge capacity. Ball milling at appropriate time can make the palladium on the alloy surface uniformly distributed and the alloy particles do not aggregate, which increases the charge-transfer reaction rate and discharge capacity. The experimental results prove that the addition of palladium and proper ball milling can effectively improve the electrochemical hydrogen storage capacity of the Co 2 B alloy.