Optimized assembling of MOF/SnO₂/Graphene leads to superior anode for lithium ion batteries

SnO₂ is one of the most promising anode materials for lithium ion batteries (LIBs). However, its cycling stability is poor due to its large volume change, and hence, its practical applications in LIBs are hindered. In this work, we propose a novel and simple strategy to enhance the performances of SnO₂-based anodes. This strategy involves optimized assembling of SnO₂ with metal organic framework (MOF) and graphene. SnO₂ nanoparticles are packed into Al-MOF in an optimum mass ratio, and then the derived SnO₂@MOF composite is wrapped by graphene, finally resulting in the SnO₂@MOF/graphene composite. This composite exhibits greatly enhanced cycling stability, i.e., the specific capacity is about 450 mA h g⁻¹ after 1000 charge/discharge cycles at the current density of 1000 mA g⁻¹. This is attributed to the unique structural configuration of the composite, which gives rich accessible electroactive sites, shortened ion transport pathways, and superior electronic conductivity. The MOF protection layer is a key for improving the lithium storage of metal oxide-based anodes. Although the capacity of the SnO₂@MOF/graphene composite is not the highest among the existing anode materials, its synthesis process is simpler and cost effective.