Effect of Ni content on the electrochemical performance of the ball-milled La 2Mg 17− xNi x + 200 wt.% Ni ( x = 0, 1, 3, 5) composites

Abstract

The effect of Ni content on the electrochemical properties of the ball-milled La 2Mg 17− x Ni x + 200 wt.% Ni ( x = 0, 1, 3, 5) composites was investigated systematically. The electrochemical results reveal that the maximum discharge capacity decreases with the increase of x value, but the cycling stability is just on the contrary. The cycle life improves with the increase of x value, which can be confirmed by the XRD results of the ball-milled composite after 20 cycles. And the high-rate dischargeability of the composite electrodes first increases and then decreases with increasing Ni content, and the ball-milled La 2Mg 16Ni + 200 wt.% Ni composite electrode exhibits the best electrochemical kinetics. In addition, the electrochemical kinetic parameters study, including the polarization resistance R p, the exchange current density I 0 and the limiting current density I l, also confirm this result.