Construction of SiO_x/nitrogen-doped carbon superstructures derived from rice husks for boosted lithium storage

Silicon sub-oxides (SiO_x) are increasingly becoming a prospective anode material for lithium-ion batteries (LIBs). Nevertheless, inferior electrical conductivity and drastic volume fluctuation upon cycling significantly hamper the electrochemical performance of SiO_x. In this work, rice husks (RHs)-derived pitaya-like SiO_x/nitrogen-doped carbon (SNC) superstructures have been prepared by a simple electrospray-carbonization approach. SiO_x nanoparticles (NPs) are well-dispersed in a spherical nitrogen-doped carbon (NC) matrix. The carbon frameworks discourage the aggregation of SiO_x NPs, facilitating the kinetics for ion diffusion and charge transfer, and maintaining structural stability upon cycling, thus bringing about improved electrochemical performance. When the optimized SNC superstructures with SiO_x content of 64.3% are utilized as LIBs anodes, a stable specific capacity of 622.8 mA h g^-1 after 100 cycles at 0.1 A g^-1, and an excellent long cycle performance of 190.1 mA h g^-1 after 5000 cycles at 5 A g^-1 are obtained. This effective and universal synthetic strategy for fabricating controllable superstructures offers insights into the development of high-performance LIBs.