Improving lithium-ion battery efficiency using Si-lithium titanium oxide and graphene coating

This paper introduces a novel approach to addressing the challenges related to the use of Si as an anode material in lithium-ion batteries (LIBs). Si is recognized for its high theoretical capacity but is limited by its significant volume expansion and low electrical conductivity. This study synthesized Si-embedded lithium titanium oxide (SLTO) by chemical vapor deposition. SLTO effectively mitigates the volume expansion of Si and enhances its overall electrochemical performance. Furthermore, a reduced graphene oxide (rGO) coating was applied to SLTO (rGO@SLTO) to establish a conductive network around the powder to improve the electrical conductivity and mitigate volume changes. X-ray diffraction and Raman spectroscopy confirmed the presence of well-coated rGO on the SLTO surface. Performance evaluation through charge-discharge tests and electrochemical impedance spectroscopy demonstrated that the optimized SLTO to rGO ratio significantly enhanced the electrical conductivity. The rGO@SLTO composite achieved an initial discharge capacity of 1890.1 mAh g⁻¹ at 1 A g⁻¹ and an initial Coulombic efficiency of 85.13%. The significantly reduced charge-transfer resistances (from 109.11 Ω without rGO to 14.54 Ω with rGO) also contributed to a significant improvement in the electrochemical performance of the LIBs.