Defect-Rich Crystalline SnO₂ Immobilized on Graphene Nanosheets with Enhanced Cycle Performance for Li Ion Batteries

A one-step microwave-assisted hydrothermal method (MAHM) has been developed to synthesize SnO 2 /graphene composites. It is shown that fine SnO 2 nanoparticles with an average size of 3.5 nm can be homogeneously deposited on graphene nanosheets (GNSs) using this technique. The electronic structure as revealed from X-ray absorption near edge structure (XANES) shows that the SnO 2 nanoparticles are abundant in surface defects with oxygen vacancies, which facilitate the immobilization of SnO 2 onto GNSs by electronic interaction. Carbon K edge XANES provide direct evidence of strong interaction between SnO 2 and GNSs. The SnO 2 /graphene nanocomposites deliver a superior reversible capacity of 635 mAh g –1 after 100 cycles and display excellent rate performance. All these desirable features strongly indicate that SnO 2 /graphene composite is a promising anode material in high-performance lithium ion batteries.