Preparation, Characterization, and Lithium Intercalation Behavior of LiVO3 Cathode Material for Lithium-Ion Batteries

A variety of LiVO3 compounds (LVO-350, LVO-400, LVO-450, and LVO-500) have been synthesized via a resorcinol-formalin assisted sol-gel method. The LiVO3 cathodes calcined at different temperatures are characterized by XRD, SEM, and galvanostatic charge/discharge to investigate the effects of annealing on the structure, morphology, and electrochemical characteristics. The results show that both crystallinity and morphology play important roles in the Li-storage properties of LiVO3; the sample annealed at 450 degrees C (LVO-450) has high crystallinity, moderated particle size, and thus exhibits the best electrochemical performance among the four electrodes. Furthermore, the Li-ion intercalation/deintercalation mechanism for LiVO3 is investigated by ex situ XRD, TEM, Raman spectroscopy, and XPS. The characterizations on the pristine and cycled LVO-450 reveal that the initial lithium insertion/extraction reaction of LiVO3 based on V5+/V4+ redox couple undergoes a successive structural transition: monoclinic LiVO3 transforms into cubic Li2VO3 upon lithium intercalation, followed by the lithiated Li2VO3 transforms into a more stable phase which has a similar crystalline structure to monoclinic LiV3O8 upon initial lithium deintercalation. Importantly, the observations in this work may provide valuable information for the design of LiVO3 and other high-capacity vanadium-based cathode materials for lithium-ion batteries.