Defect-rich crystalline SnO ₂ 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.