Multi-electron reactions for the synthesis of a vanadium-based amorphous material as lithium-ion battery cathode with high specific capacity

Abstract

The vanadium-based amorphous electrode material can realize the valence state conversion and increase its specific capacity through the multi-electron reaction. We have obtained V2O5–Li3PO4 glass with a strong reducing agent CaC2, realizing a multi-electron reaction of V5+ to V4+ and then to V3+ in the model system. Moreover, we have explored the relationship between valence state, crystallinity, and conductivity limit to compare the cycle performances of amorphous glass batteries. The CaC2 content of 20%, V4+ presented the dominating valence state with a content of 77.5%. VP-C20% exhibited a maximum specific capacity of 319.3 mAh g−1, and the specific capacity after 100 cycles was 280.3 mAh g−1, corresponding to a retention capacity of 87.8%. The electrochemical performance of amorphous vanadium oxide decreased with the increase of the LiV2O5’s nanocrystallinity. Crystallinity and the controllable multi-electron reaction could provide an important reference for designing other new electrode materials with high capacity and long cycle life.