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

Abstract

Silicon sub-oxides (SiOx) 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 SiOx. In this work, rice husks (RHs)-derived pitaya-like SiOx/nitrogen-doped carbon (SNC) superstructures have been prepared by a simple electrospray-carbonization approach. SiOx nanoparticles (NPs) are well-dispersed in a spherical nitrogen-doped carbon (NC) matrix. The carbon frameworks discourage the aggregation of SiOx 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 SiOx 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.