Mg-based hydrogen storage alloys Mg_0.9Ti_0.1Ni_1－xCo_x (x＝0.05, 0.1, 0.15, 0.2) were prepared by means of mechanical alloying, and the structure and the electrochemical characteristics of these Mg-based electrodes were also studied. The result of X-ray diffraction and transmission electron microscope showed that the main phase of the alloys had amorphous structures, and some trace of weak Ni peaks might co-exist. The charge-discharge cycle tests indicate that these alloys have good electrochemistry activation characteristics, and the cycle performance of these alloys were better than those of MgNi alloys. Among such alloys, the discharge capacity of Mg_0.9Ti_0.1Ni_0.8Co_0.2 was the highest, up to 427.5 mAh•g^－1. In the process of charge-discharge cycle test, the main reason of the electrode capacity decay is that Mg may become Mg(OH)₂ on the surface of alloys. The corrosion curve test indicates that the Co addition can improve the anticorrosion performance of these alloys in the alkali solution and the cycle stability of these alloy electrodes.

Key words: Mg-based hydrogen storage alloy, cycle stability, anticorrosion performance