TiO2/Reduced-Graphene-Oxide Double-Layer-Coated SiO as High-Performance Anode for Lithium-Ion Batteries

Silicon monoxide (SiO) is promising to be anode materials for next-generation lithium-ion batteries owing to its high capacity, but its application is hindered by the poor electrical conductivity, large volume expansion (approximate to 150%) caused by the lithiation, and low lithium-ion transport efficiency. Herein, TiO2/reduced graphene oxide (rGO) double-layer-coating strategy is proposed to solve the earlier issues. The anatase phase of TiO2 provides high mechanical strength and partial capacity in the SiO anode, and its lithiation product (LixTiO2) greatly enhances the lithium-ion transport efficiency. The rGO coating on SiO makes a great contribution to suppressing the volume expansion of SiO particles during the lithiation and improves the electrical conductivity of SiO electrodes. The double-layer coating strategy isolates SiO from direct contact with the electrolyte, reduces the loss of electrolyte, and improves the Coulombic efficiency of the batteries. Consequently, the TiO2/rGO double-layer-coated SiO composite maintains a capacity of 670 mAh g(-1) after 200 cycles at 0.5 A g(-1). The results indicate that the structural design of SiO@TiO2-rGO composite can solve the drawbacks of SiO and improve its cycling performance. Herein, a new route to prepare high-performance SiO-based anode for lithium-ion batteries is provided.