Microbelt–void–microbelt-structured SnO2@C as an advanced electrode with outstanding rate capability and high reversibility

Abstract

Nanoscale SnO₂ materials are highly active in charge/discharge processes, but suffer from both poor interconnectivity and re-agglomeration. In this paper, we report the development of a novel microbelt–void–microbelt SnO₂@C structure, in which the inner SnO₂ nanoparticles-derived microbelt possessed the advantage of high reactivity, the abundant void space effectively buffered the volume change, and the outer microscale carbon shell supplied a fast convenient electronic conduction path and shortened the ion-diffusion distance. Resultant microbelt–void–microbelt-structured SnO₂@C-based half cells delivered a high capacity of 1227 mA h g⁻¹ after 300 cycles at 300 mA g⁻¹, and a superior rate performance of 509 mA h g⁻¹ at a high current density of 10 A g⁻¹. The full-cell measurements coupling with LiCoO₂ showed a high capacity of 588 mA h g⁻¹ after 100 cycles. The superior electrochemical performance may be attributed to the unique microbelt–void–microbelt structure, which enables highly reversible alloying and allows the conversion reaction of SnO₂ to Sn in the long-term cyclic processes.