Green synthesis of SiOx/C-TiO2 with continuous conductive network towards enhancing lithium storage performance

Abstract

High-capacity SiO_x anodes face significant challenges in practical applications due to their low conductivity and high expansion rate. The combination of nanoengineering and carbon capping processes has been proven to address these issues. However, most carbon capping techniques cannot ensure uniform capping and fail to form a continuous conductive phase between active materials. This work proposes a green (solvent-free) and facile method for constructing SiO_x/C-TiO₂ (SCT@CN) nanocomposites by creating a three-dimensional carbon conductive network from gelatin-derived carbon and doping with titanium dioxide nanoparticles (TiO₂ NPs). Comparison of TiO₂ NPs with varying doping levels reveals that the synergistic effect between the conductive carbon network and TiO₂ NPs enhances both the structural stability of batteries during charge/discharge cycles and the efficiency of active material utilization and lithium-ion diffusion. With the increase of TiO₂ NPs, the capacity retention and ICE of the electrode improved, while the initial discharge capacity decreased. Notably, the SCT-2@CN electrode with 10 wt% TiO₂ NPs exhibits the best electrochemical performance, with an initial coulombic efficiency (ICE) of 73.2 %. After 700 cycles at a high current density of 2.0 A g⁻¹, it maintained a capacity of 503 mAh g⁻¹, with a capacity retention rate of 81.86 %. The optimized carbon capping process and introduction of novel elements have the potential to enhance a range of energy storage materials.