Enhanced cycling performance of lithium-ion batteries with V₂O₅ as cathode by Co-doping for structural stability

The high capacity and cycling performance are important for the lithium-ion battery (LIB). V₂O₅ is considered a good active material among various potential candidates due to its low cost, abundant availability, and high energy density, however, the disadvantage of lower cycling performance is difficult to solve due to structural instability during the charging and discharging process. Here, we prepared composite microspheres of Co-doped V₂O₅ by a simple solvothermal method for solving structural instability. As the cathode material in LIBs, the V₂O₅-Co_0.1 composite microspheres exhibit a specific capacity of 171 mAhg⁻¹ at a current density of 0.08 Ag⁻¹ (except for the first cycle). After 10 cycles, the specific capacity of V₂O₅-Co_0.1 composite microspheres did not change, it exhibited better cycling stability. When the current density is increased to 0.1 Ag⁻¹ and 0.3 Ag⁻¹, 241 mAhg⁻¹ and 200 mAhg⁻¹ specific capacities are obtained. Although the initial specific capacity of pure V₂O₅ microspheres was higher than that of V₂O₅-Co_0.1, its capacity retention after cycling was 86%, which was lower than that of V₂O₅-Co_0.1. The reason for the enhanced stability of V₂O₅-Co_0.1 composite microspheres is that Co ions are fixed between the layered structures of V₂O₅, which increases the stability of the V₂O₅ structure.