Abstract:

The surface of an amorphous Mg45Ti3V2Ni50 alloy was modified with Ti, B, and a specific composite TiB by high energy ball-milling. Experimental results showed that after modification the electrochemical stability of the hydrogen storage alloy improved and the improvement for TiB was much more than that for Ti or B. The initial discharge capacity of the Mg45Ti3V2Ni50-TiB alloy electrode (mass ratio 2:1) was 529.4 mAh·g-1 and after 50 cycles the discharge capacity was 277.1 mAh·g-1. A synergistic effect between the metal and nonmetal was formed evidently not only between Ti and B in TiB but also between TiB and the Mg45Ti3V2Ni50 alloy. This synergistic effect enhanced the interaction between the modified layer and the Mg45Ti3V2Ni50 alloy. A new stereochemical pleats structure was formed by the synergistic effect between the metal and the nonmetal. The surface activity of the Mg45Ti3V2Ni50 alloy was increased and the electrochemical cycling stability improved greatly.

Key words: Mg-based hydrogen storage alloy, Cycle stability, Surface modification, Synergistic effect