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

Amorphous vanadates are of increasing interest for use as electrode materials in lithium ion batteries. A series of (100-x)(40 V 2 O 5 -60TeO 2 )-xCoO (x = 0, 5, 10, 15, 20, 25) glasses were obtained by traditional melt quenching method. The initial discharge capacity of the 40 V 2 O 5 -60TeO 2 glass was 416.0 mAh g −1 , while the initial discharge capacity of the 34 V 2 O 5 -51TeO 2 -15CoO (x = 15) glass reached 726.4 mAh g −1 . Among all glass samples, 34V2O5–51TeO2–15CoO glass had the highest V 4+ content (52.26%) and showed the best electrical conductivity. The addition of CoO increases the content of V 4+ , realizing a multi-electron reaction of Co 2+ /Co 0 , which enhances the electronic conductivity and capacity. It also increases the content of NBO as well as the number of VO 5 units decreases with a corresponding increase in the number of VO 4 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. • The addition of CoO increases the content of V 4+ and improves the transport of electrons. • On the basis of V 5+ /V 4+ /V 3+ electron reaction, the addition of CoO provides Co 2+ /Co 0 , a multi-electron reaction, which enhances the electronic conductivity and capacity. • Compared with V 2 O 5 -TeO 2 , the increase of VO 4 units and NBO ions leads to a looser structure of V 2 O 5 -TeO 2 -CoO, improves ions diffusion coefficient and provides more channels and sites for Li + transport and insertion-extraction.