Space-Confined Synthesis of Ultrasmall SnO₂ Nanodots within Ordered Mesoporous Carbon CMK‑3 for High-Performance Lithium Ion Batteries

SnO₂ suffers from the severe pulverization problem when used as an anode material for lithium ion batteries (LIBs). To overcome its drawbacks, hybridizing nanosized SnO₂ with carbon-based materials is very impactful, and we herein successfully synthesize ultrasmall SnO₂ nanodots (average size of around 5 nm) within the channels of the commercial ordered mesoporous carbon (CMK-3), in which the tin precursor is prefilled under a vacuum and then is easily converted into SnO₂ by annealing at 350 °C in air. The as-prepared SnO₂@CMK-3 composite demonstrates good lithium storage properties, displaying a discharge capacity of 898.8 mA h/g at the 150th cycle at 500 mA/g, apparently higher than that for the bare SnO₂ and CMK-3 electrodes. The superior electrochemical performance of SnO₂@CMK-3 can be due to the high conductivity and vast pore volume of the CMK-3 carbon matrices, which efficiently alleviate the volume change induced pulverization and enhance the electrode conductivity. Besides, the uniform distribution of the ultrasmall SnO₂ nanodots within CMK-3 maximally enlarges the lithium storage sites and minimizes the effect of the volume variation.