Enhanced the Long-Cycle Performance of SiOx/C Anode Materials Via Ti and Sn Bimetallic Doping Strategy

Abstract

Silicon oxide (SiO_x), due to its significant reversible capacity and significantly reduced volume expansion compared to pure silicon, holds promise as a candidate for high-performance lithium-ion battery anode materials. Unfortunately, SiO_x still faces challenges for commercialization due to its volume expansion exceeding 160 %, low initial coulombic efficiency, and low electrical conductivity. In this study, we employed metal oxides containing Ti and Sn to dope SiO_x/C materials, utilizing a sol-gel method to prepare SiO_x/TiO₂/SnO₂/C composite anode materials. Furthermore, we adjusted the doping ratios of Sn and Ti to explore the optimal amount for improving the electrochemical performance of the material. Ultimately, it was found that the SiO_x/TiO₂/SnO₂/C composite material prepared with a molar ratio of silicon, titanium, and tin at 10 : 0.7 : 0.3 exhibited the best performance, achieving an initial discharge capacity of 1845.33 mAh ⋅ g⁻¹ at a current density of 100 mA ⋅ g⁻¹ and maintaining a reversible capacity of 843.41 mAh ⋅ g⁻¹ after 100 cycles, with a capacity retention rate of 75.9 %. This work provides a relatively simple method to composite Ti and Sn metal oxides with SiO_x, introducing additional conductive pathways to enhance the material‘s conductivity.