Electrode properties of La2Mg17 alloy ball-milled with x wt.% cobalt powder (x = 50, 100, 150 and 200)

La2Mg17 alloy prepared by induction was ball-milled with different amounts of metallic cobalt powder. The effect of the ball-milling on the alloy microstructure and surface image was examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD results showed that the more Co added, the higher amorphization degree could be obtained. Electrochemical characteristics of the composite electrodes were investigated at 303 K. The discharge capacity and high-rate dischargeability increased with the increment of Co amount added because of the changed structure and surface state of the alloy, and the high-rate dischargeability is mainly determined by the charge-transfer process occurring at the metal/electrolyte interface, namely, the exchange current density I0. But the cycling stability deteriorated with the increase of Co amount introduced during ball-milling.