Improvement of Electrochemical Performance of KVO3 as High Capacity Negative Electrode Material for Lithium-ion Batteries

Vanadium oxide based materials have been studied as novel negative electrode materials in lithium-ion batteries (LIBs) because of their high specific capacity. In this study, potassium metavanadate (KVO3) was synthesized and its electrochemical properties are evaluated as a negative electrode materials. The aqueous solution of NH4VO3 is mixed with a stoichiometric amount of KOH. The solution is boiled to remove NH3 gas and dried to obtain a precipitate. The obtained KVO3 powders are heat-treated at 300 and 500 degrees C for 8 h in air. As the heat treatment temperature increases, the initial reversible capacity decreases, but the cycle performance and Coulombic efficiency are improved slightly. On the contrary, the electrochemical performances of the KVO3 electrodes are greatly improved when a polyacrylic acid (PAA) as binder was used instead of polyvinylidene fluoride (PVDF) and a fluoroethylene carbonate (FEC) was used as electrolyte additive. The initial reversible capacity of the KVO3 is 1169 mAh/g and the Coulombic efficiency is improved to 76.3% with moderate cycle performance. The KVO3 has the potential as a novel high-capacity negative electrode materials.