Microstructure and electrochemical properties of mechanically ground Ce2Mg17 + x wt.% Ni (x = 0, 50, 100, 200) composites

The effects of mechanical grinding with or without nickel powder on microstructure and electrochemical properties of Ce2Mg17 hydrogen storage alloy in 6 M KOH solution were investigated. The microstructure and electrochemical properties depend greatly on the amount of nickel powder introduced during mechanical grinding. For the alloy ball-milled with nickel powder, the more nickel powder added, the more advantageous it is for the formation of a homogeneous amorphous structure, and the larger discharge capacity obtained. After 90 h ball-milling, the Ce2Mg17 + 200 wt.% Ni composite exhibited a large discharge capacity of 1014 mAh g(Ce2Mg17)−1[338 mAh g(Ce2Mg17 + 200 wt.% Ni)−1] at 303 K. The improvement of electrochemical capacity can be attributed to the formation of a homogeneous amorphous structure as well as the modification of the surface state by Ni addition.