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

[Display omitted] • Pitaya-like SiO x /nitrogen-doped carbon superstructures are prepared as an anode in LIBs. • Nanosized SiO x obtained from the renewable rice husks shortens the electron and Li+ diffusion path. • The integrated carbon matrix prevents the aggregation of SiO x NPs, and improves the kinetics and structural stability. • This electrospray strategy is economic, effective and universal for fabricating superstructures. 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. [ABSTRACT FROM AUTHOR]