SnO2/graphene composite with high lithium storage capability for lithium rechargeable batteries

SnO2/graphene nanocomposites have been fabricated by a simple chemical method. In the fabrication process, the control of surface charge causes echinoid-like SnO2 nanoparticles to be formed and uniformly decorated on the graphene. The electrostatic attraction between a graphene nanosheet (GNS) and the echinoid-like SnO2 particles under controlled pH creates a unique nanostructure in which extremely small SnO2 particles are uniformly dispersed on the GNS. The SnO2/graphene nanocomposite has been shown to perform as a high capacity anode with good cycling behavior in lithium rechargeable batteries. The anode retained a reversible capacity of 634 mA·h·g−1 with a coulombic efficiency of 98% after 50 cycles. The high reversibility can be attributed to the mechanical buffering by the GNS against the large volume change of SnO2 during delithiation/lithiation reactions. Furthermore, the power capability is significantly enhanced due to the nanostructure, which enables facile electron transport through the GNS and fast delithiation/lithiation reactions within the echinoid-like nano-SnO2. The route suggested here for the fabrication of SnO2/graphene hybrid materials is a simple economical route for the preparation of other graphene-based hybrid materials which can be employed in many different fields.