Co2+/Co0 enhances the capacity of lithium-ion batteries in vanadium-based glass anode

Abstract

Amorphous vanadates are of increasing interest for use as electrode materials in lithium ion batteries. A series of (100-x)(40 V2O5-60TeO2)-xCoO (x = 0, 5, 10, 15, 20, 25) glasses were obtained by traditional melt quenching method. The initial discharge capacity of the 40 V2O5-60TeO2 glass was 416.0 mAh g−1, while the initial discharge capacity of the 34 V2O5-51TeO2-15CoO (x = 15) glass reached 726.4 mAh g−1. Among all glass samples, 34V2O5–51TeO2–15CoO glass had the highest V4+ content (52.26%) and showed the best electrical conductivity. The addition of CoO increases the content of V4+, realizing a multi-electron reaction of Co2+/Co0, which enhances the electronic conductivity and capacity. It also increases the content of NBO as well as the number of VO5 units decreases with a corresponding increase in the number of VO4 units, leading to an inferior connection between structural units of glasses and loosening the glass structure. Consequently, the space for Li+ transmission increases, thereby providing more sites for Li+ insertion-extraction. This work provides a novel multi-electron reaction ternary glass anode material for the preparation of lithium-ion battery.