Vanadium-Substituted Formation of Anatase (V, Ti)O2: Enhanced Electrochemical Performance for Lithium Ion Batteries

TiO2 has been used as a commercial anode material in lithium ion batteries (LIBs) owing to security and outstanding cycle stability. However, the lower specific capacity has limited its application. In this work, nanocrystalline anatase (V0.47, Ti0.53)O2 is prepared via a hydrothermal process. When evaluated as an anode material for LIBs, nanocrystalline (V, Ti)O2 exhibits enhanced specific capacity, high rate performance, and excellent cyclic stability. The specific capacity of the (V, Ti)O2 anode reaches 370 mAh g–1 in the first cycle, about 2.2 times the theoretical capacity of anatase TiO2, and it retains a value of 320 mAh g–1 after 500 cycles at a current density of 168 mA g–1. At a current density of 1680 mA g–1 (10 C), a specific capacity of as high as 137 mAh g–1 is achieved after 1000 cycles. The high capacity is ascribed to the incorporated vanadium element, which undergoes the redox reactions of V4+ → V3+ → V2+ during the lithium storage process according to the ex-situ XPS results. The increased conductivity and surface pseudocapacitive contribution of the (V, Ti)O2 anode as evidenced by the EIS and rate-changing CV investigation account for the improved rate performance with respect to TiO2. This work demonstrates that (V, Ti)O2 nanoparticles are a promising candidate for LIB anode materials.