Facile Synthesis of Core-Shell Structured SiO₂@Carbon Composite Nanorods for High-Performance Lithium-Ion Batteries

Recently, SiO₂ has attracted wide attention in lithium-ion batteries owing to its high theoretical capacity and low cost. However, the utilization of SiO₂ is impeded by the enormous volume expansion and low electric conductivity. Although constructing SiO₂/carbon composite can significantly enhance the electrochemical performance, the skillful preparation of the well-defined SiO₂/carbon composite is still a remaining challenge. Here, a facile strategy of in situ coating of polydopamine is applied to synthesis of a series of core-shell structured SiO₂@carbon composite nanorods with different thicknesses of carbon shells. The carbon shell uniformly coated on the surface of SiO₂ nanorods significantly suppresses the volume expansion to some extent, as well as improves the electric conductivity of SiO₂. Therefore, the composite nanorods exhibit a remarkable electrochemical performance as the electrode materials of lithium-ion batteries. For instance, a high and stable reversible capacity at a current density of 100 mA g^-1 reaches 690 mAh g^-1 and a capacity of 344.9 mAh g^-1 can be achieved even at the high current density of 1000 mA g^-1. In addition, excellent capacity retention reaches 95% over 100 cycles. These SiO₂@carbon composite nanorods with decent electrochemical performances hold great potential for applications in lithium-ion batteries.