Effects of V2O5 and Fe2O3 on the structures and electrochemical performances of Li2O-V2O5-B2O3 glass materials in lithium-ion batteries

Among new lithium-ion battery cathode materials, amorphous materials show unique advantages and vanadium-based materials are potential electrode materials. In our study, the vanadium-based Li2O-V2O5-B2O3 glassy state electrode materials with high vanadium contents were prepared in air by the meltquenching method. The structures and electrochemical performances of glass materials were investigated by various characterization methods. The Li2O-V2O5-B2O glass were mainly connected with VO4 and BO3 structural units to form a disordered network structure. The first discharge capacity of 20Li(2)O-60 V2O5-20B(2)O(3) glass cathode material reached 168.6 mAh/g at a current density of 100 mA/g. The conversion of V3+/V4+ and V4+/V5+ mainly occurred in the charge and discharge cycles. When 10% of B2O3 was replaced by Fe2O3, the compactness and stability of the material were improved. Furthermore, with the addition of Fe2O3, the concentrations of low-valence V4+, V3+ and Fe2+ ions increased, thus contributing to the elec-trochemical performance. The specific capacity of 20Li(2)O-60V(2)O(5)-10B(2)O(3)-10Fe(2)O(3) cathode material increased significantly and the first discharge capacity was as high as 306.2 mA h/g at a current density of 100 mA/g. However, the specific capacity respectively decreased to 239 mA h/g in the second cycle and 120.3 mA h/g after 100 cycles. The study on vanadium-based glass cathode materials provided a new idea for the investigation of novel cathode materials for lithium-ion batteries. (C) 2021 Elsevier B.V. All rights reserved.