Effects of surface modification on the electrode behavior of ball-milled La2Mg17 + 200 wt% Ni composite in alkaline solution

The ball-milled La2Mg17 + 200 wt% Ni composite is modified with graphite, aluminum, cobalt, titanium and nickel (weight ratio: 5 wt%) by ball-milling for 90 min. The microstructures of the obtained materials were examined by X-ray diffraction and SEM. The electrochemical properties of the obtained materials were measured and compared with those of the original ball-milled composite. It was found that the maximum discharge capacity and high-rate dischargeability of the composites after surface modification by graphite, Co and Ni increased to some extent due to the electrocatalytic activity of the coating element and the decrease of electrochemical reaction resistance on the alloy surface, but the effect of Al and Ti was just on the contrary. On the other hand, the cycling stability of the composites modified with Al, Ti and Ni all improved, and the modification with Ti was the most effective in improving the cycle life. But the modification with graphite, Co led to the worsening of the cycling stability to different degree, especially the modification with graphite.