Effect of palladium addition on electrochemical hydrogen storage properties of Co0.9Cu0.1Si alloy

Abstract Co 0.9 Cu 0.1 Si alloy was fabricated via mechanical alloying technique. Different amount of palladium was doped into the Co 0.9 Cu 0.1 Si alloy by ball milling. The composite alloy combined the excellent electrocatalysis activity of Pd, exhibiting preferable electrochemical performance than the original alloy. The Co 0.9 Cu 0.1 Si + 5 wt% Pd composite showed a C max of 559.2 mAh/g, significantly higher than that for Co 0.9 Cu 0.1 Si (502.1 mAh/g). The cycle stability was also enhanced after Pd loading. Moreover, the effect of ball milling time on electrochemical performance for the composite alloy was also investigated. 5 wt% Pd was mixed with the Co 0.9 Cu 0.1 Si alloy at different ball milling time (0.5 h, 1 h, 2 h, 3 h and 5 h). The optimal discharge capacity, capacity retention and high-rate dischargeability were obtained under the ball milling time of 2 h. The studies on electrochemical reaction kinetics demonstrated that the addition of Pd could accelerate the charge-transfer, thus enhancing the electrochemical activity and reaction kinetics of the alloy. The results indicated that Pd loading was an effective way in enhancing the electrochemical performance of Co 0.9 Cu 0.1 Si alloy.