One-Step Low-Temperature Fluoride Salt Synthesis of High-Defect LiV₃O₈ Microrod Cathodes with Exceptional Performance

With the growing demand for high-performance lithium-ion batteries, developing energy-efficient and simple synthesis methods to enhance the electrochemical performance of LVO (LiV₃O₈) has become a critical challenge. This study presents an low-temperature fluoride salt solid-state synthesis method, utilizing lithium fluoride (LiF) simultaneously as both the lithium source and flux. This approach initiates the formation of lithium trivanadate (LVO) at 400 °C and achieves complete reaction at 550 °C, enabling the one-step direct preparation of pure-phase, microrod-shaped LVO with a high oxygen vacancy concentration (approximately 16.5 at. %). Electrochemical performance tests demonstrate that the material delivers specific discharge capacities of 335.5, 333.9, 313.6, 249.5, 174.5, 144.3, 129.9, and 109.1 mAh g^-1 at current densities of 50, 100, 200, 400, 800, 1200, 1500, and 2000 mA g^-1, respectively. Notably, at a high rate of 1000 mA g^-1 during long-cycle testing, the material maintains an initial capacity of 156.3 mAh g^-1, with a capacity retention of 83.17% after 400 cycles. The excellent electrochemical performance of this material can be attributed to its unique microrod-shaped morphology and the introduced high concentration of oxygen vacancy defects, which synergistically enhance lithium-ion storage kinetics and structural stability. The developed one-step low-temperature synthesis strategy successfully achieves the controllable preparation of LVO integrating both high oxygen vacancy concentration and a microrod morphology, providing a pathway for the design and synthesis of high-performance lithium-ion battery cathode materials.