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 SnO2/graphene composites. It is shown that fine SnO2 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 SnO2 nanoparticles are abundant in surface defects with oxygen vacancies, which facilitate the immobilization of SnO2 onto GNSs by electronic interaction. Carbon K edge XANES provide direct evidence of strong interaction between SnO2 and GNSs. The SnO2/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 SnO2/graphene composite is a promising anode material in high-performance lithium ion batteries.