Advancing Li3VO4 as a high-performance anode material for use in lithium-ion batteries and lithium-ion capacitors

Abstract

Li3VO4 (LVO) is a promising anode material for use in Li-ion batteries (LIBs) owing to its safe discharge plateau and high capacity. However, its moderate Li+-diffusion coefficient and low electrical conductivity pose challenges to its widespread use in the LIB industry. In this study, hexavalent tungsten ions (W6+) were introduced to boost electrochemical kinetics, and W6+-doped LVO microspheres were successfully prepared using a spraydrying approach. Density functional theory (DFT) calculations reveal that the enhanced electronic conductivity and improved oxygen lattice following W6+ doping is possibly due to the development of a mid-gap state positioned above the valence band maximum. The doped LVO displayed excellent electrochemical performance, including a superior rate capability (288.9 mAh/g at 10C) and remarkable cycling stability (capacity fading of only 8.6 % over 200 cycles at 6C), which is ascribable to improved electrical conductivity and Li+ insertion/ extraction. In addition, we also fabricated a 3.7 V full LIB with a W6+-doped LVO anode and a LiNi0.5Mn1.5O4 (LNMO) cathode, and a lithium-ion capacitor (LIC) with an energy density of 131.8 Wh/kg using the modified LVO and active carbon (AC). This study demonstrates the potential of W6+-doped LVO for use in energy-storage applications.