SnO/SnO₂ Heterojunction Nanoparticles Anchored on Graphene Nanosheets for Lithium Storage

Engineering heterojunction composite structures consisting of multiple nano active components formed from single element is broadly acknowledged as a robust method to boost the electrochemical performance of lithium-ion batteries (LIBs). Herein, a multidimensional composite structure consisting of SnO/SnO₂ heterojunction nanoparticles and reduced graphene oxide nanosheets (SnO/SnO₂@G) is proposed. The extensive empirical characterization and density functional theory (DFT) calculations validate the plentiful heterogeneous interfaces and resilient lithium storage mechanism exhibited by the SnO/SnO₂ heterostructures. These attributes are closely associated with the rapid diffusion kinetics of Li⁺ within the space charge region and the presence of multiple-ion channels. On the other hand, the Sn-O-C bond is anchored on graphene sheets, enhancing SnO/SnO₂ heterostructure stability and preventing unavoidable aggregation and slow charge transfer. As anticipated, the better specific capacity, rate performance, and cycling stability (498.69 mAh g^-1 at 1.0 A g^-1 after 400 cycles) are acquired in the LIBs composed of a SnO/SnO₂@G anode. This work provides a feasible approach for improving the performance of LIBs by constructing single-element heterostructures.