Preparation and electrochemical performance of LiF-V2O3 composite cathode for lithium-ion batteries

Conversion reactions have made LiF-metal oxide (MO) composites with attractive specific capacities compelling candidates for the next generation of lithium-ion battery cathode materials. However, it is necessary for the high charge voltage (> 4.5 V) to drive the redox reaction of MOs and break a strong ionic bond between Li⁺ and F⁻ upon charge. It is a crucial way for decrease in the charge voltage to lower the activation energy barrier of the redox process between LiF and MOs. A novel conversion cathode LiF-V₂O₃ system is proposed in this study. Unlike most of the previously reported LiF-MOs systems, the LiF-V₂O₃ system can work at the lower charge cut off voltage of 4.3 V. It delivers a reversible specific capacity of 197 mAh g⁻¹ at C/20 rate in the voltage range of 2–4.3 V. Cyclic voltammetry data suggest a dominant contribution of pseudocapacitance effect in the conversion reaction of the LiF-V₂O₃ sample.