Effect of ball-milling time on the electrochemical performance of ball-milled LaMg_(11)Ni + 200 wt percent Ni composite

摘要

The effect of ball-milling time on the overall electrochemical properties of LaMg_(11) Ni + 200 wt percent Ni composite has been studied systematically. The results show that ball-milling time has a striking effect on the overall electrochemical properties. The maximum discharge capacity increases first and then decreases with the increase of ball-milling time from 60 to 120 h, and the cycling stability is just on the contrary. The high-rate dischargeability increases a little with increasing ball-milling time. Detailed studies on the ball-milling time effect on the polarization resistance (R_p), the exchange current density (I_0) and limiting current density (I_L) indicate that the diffusion of hydrogen in the bulk of LaMg_(11) Ni + 200 wt percent Ni composite electrodes is the rate-determining factor for the discharge process of the alloy electrode.