▎ 摘　　要

A reduced graphene oxide supported cobalt (Co@G) was synthesized via a wet-chemical method and was then introduced into a La0.7Mg0.3 (Ni0.85Co0.15) 3.5 alloy (designated as La-Mg-Ni) by means of mechanical alloying. Experimental results indicated that the La-Mg-Ni alloy electrodes decorated with Co@G nanocomposites exhibited excellent electrochemical performance. At a discharge current density of 1200 mA/g, the high rate dischargeability (HRD1200) of the undecorated alloy electrode was 59.8%. This value increased to 82.3%, 84.7%, and 70.7%, respectively, when the alloy electrode was decorated with x wt.% (x=3,6,9) Co@G nanocomposites, respectively. The exchange current density (I-0) and the limiting current density (I-L) were also enhanced under the catalytic action of the Co@G nacocomposites. The electrode decorated with the 6.0 wt.% Co@G nanocomposite exhibited the best electrochemical performance. The improvements in electrochemical performance of the La-Mg-Ni alloy electrodes are attributed to the synergistic catalytic action of graphene and Co, thereby facilitating the electron transport and shortening the ion transportation paths in the alloy electrodes.