テルミットプロセスによるV系高性能リチウム二次電池負極材料の開発

抄録

Tin-based alloys are receiving much attention as new anode materials with high energy density for Li-ion secondary batteries. However, these alloys still show very poor cycle life because charge-discharge processes cause cracking and crumbling of the anode by large volume changes in the alloys.
In order to overcome the problem, we have proposed vanadium-based alloys which had very good ductility. Tin-vanadium alloys were successfully prepared by thermic process in which vanadium-oxide was reduced by Al-metal to vanadium-metal. The obtained Sn-V alloys are mainly composed of Sn₃V₂ phase containing tin impurity. Cycle life of the alloy anode was significantly improved by annealing it at 750°C because the amount of impurity tin was decreased greatly. The Sn₃V₂ alloy anode showed an initial rechargeable capacity of 500 Ah/kg, keeping 400 Ah/kg even after 50 charge-discharge cycles.