Vanadium-doped Li2TiSiO5 anodes for boosting capacity and cycling stability of lithium-ion batteries†

Abstract

Lithium-ion batteries (LIBs) represent one of the most ideal electrochemical energy storage devices due to their long cycle life, high specific energy, and high-power density. Li₂TiSiO₅ (LTSO) has been proposed as a promising anode material for LIBs, because of its favorable operating potential of 0.28 V vs. Li⁺/Li and desired safety and stability. However, its application has been significantly impeded by some key drawbacks, including slow Li⁺ transfer rates and low electrical conductivity. Herein, we proposed vanadium(V)-doping engineering for synthesizing Li₂Ti_1−xV_xSiO₅ (x = 0, 0.25, 0.5, 0.75) anode materials via a sol–gel method. Because of the partial replacement Ti⁴⁺ with V⁵⁺ ions in the structure, the as-prepared V-doped Li₂Ti_0.95V_0.05SiO₅ shows a high reversible capacity of 235 mA h g⁻¹ after 130 cycles at a rate of 0.5 A g⁻¹, nearly three-fold that of the pristine LTSO anode. The improved cycling stability and multiplicity performances are largely attributed to the increased conductivity, and this excellent lithium storage performance opens up new opportunities for further practical applications of novel silicon-based carbon materials as electrode materials in high-power storage devices. This study provides a simple and effective method for fabricating high-performance LTSO anode materials, thus facilitating their practical applications in rechargeable LIBs.