Nanosize SnO2 confined in the porous shells of carbon cages for kinetically efficient and long-term lithium storage

Abstract

We explore a hybrid material consisting of SnO₂ nanoparticles (NPs) embedded in the porous shells of carbon cages (SnO₂–PSCC). The hybrid material exhibits improved kinetics of lithiation–delithiation and high reversible capacity, and excellent cyclic stability without capacity loss over 100 cycles at 500 mA g⁻¹ with a coulombic efficiency close to 100% after the initial cycle. This can be ascribed to the high electrical conductivity, the hierarchical porosity and the confinement effect of the PSCC on the volume change of SnO₂ NPs. The material has a large reversible capacity of 460 mA h g⁻¹ at a high current density of 5 A g⁻¹ due to a short ion diffusion length in the bulk and large number of inter-pore ion transport channels. These results provide insight into improving the lithium storage performance of SnO₂ by facilitating the reaction kinetics and indicate that this hybrid material has great potential for use in high-rate and durable lithium ion batteries.