Solvent‐Free Synthesis of Uniform MOF Shell‐Derived Carbon Confined SnO2/Co Nanocubes for Highly Reversible Lithium Storage

Tin dioxide (SnO 2 ) has attracted much attention in lithium‐ion batteries (LIBs) due to its abundant source, low cost, and high theoretical capacity. However, the large volume variation, irreversible conversion reaction limit its further practical application in next‐generation LIBs. Here, a novel solvent‐free approach to construct uniform metal–organic framework (MOF) shell‐derived carbon confined SnO 2 /Co (SnO 2 /Co@C) nanocubes via a two‐step heat treatment is developed. In particular, MOF‐coated CoSnO 3 hollow nanocubes are for the first time synthesized as the intermediate product by an extremely simple thermal solid‐phase reaction, which is further developed as a general strategy to successfully obtain other uniform MOF‐coated metal oxides. The as‐synthesized SnO 2 /Co@C nanocubes, when tested as LIB anodes, exhibit a highly reversible discharge capacity of 800 mAh g −1 after 100 cycles at 200 mA g −1 and excellent cycling stability with a retained capacity of 400 mAh g −1 after 1800 cycles at 5 A g −1 . The experimental analyses demonstrate that these excellent performances are mainly ascribed to the delicate structure and a synergistic effect between Co and SnO 2 . This facile synthetic approach will greatly contribute to the development of functional metal oxide‐based and MOF‐assisted nanostructures in many frontier applications.