In Situ Generation of Few‐Layer Graphene Coatings on SnO₂‐SiC Core‐Shell Nanoparticles for High‐Performance Lithium‐Ion Storage

Abstract

Abstract A simple ball‐milling method is used to synthesize a tin oxide‐silicon carbide/few‐layer graphene core‐shell structure in which nanometer‐sized SnO 2 particles are uniformly dispersed on a supporting SiC core and encapsulated with few‐layer graphene coatings by in situ mechanical peeling. The SnO 2 ‐SiC/G nanocomposite material delivers a high reversible capacity of 810 mA h g −1 and 83% capacity retention over 150 charge/discharge cycles between 1.5 and 0.01 V at a rate of 0.1 A g −1 . A high reversible capacity of 425 mA h g −1 also can be obtained at a rate of 2 A g −1 . When discharged (Li extraction) to a higher potential at 3.0 V (vs. Li/Li + ), the SnO 2 ‐SiC/G nanocomposite material delivers a reversible capacity of 1451 mA h g −1 (based on the SnO 2 mass), which corresponds to 97% of the expected theoretical capacity (1494 mA h g −1 , 8.4 equivalent of lithium per SnO 2 ), and exhibits good cyclability. This result suggests that the core‐shell nanostructure can achieve a completely reversible transformation from Li 4.4 Sn to SnO 2 during discharging (i.e., Li extraction by dealloying and a reversible conversion reaction, generating 8.4 electrons). This suggests that simple mechanical milling can be a powerful approach to improve the stability of high‐performance electrode materials involving structural conversion and transformation.