▎ 摘　　要

Benefiting from the reversible conversion reaction upon delithiation, nanosized SnO2, with its theoretical capacity of 1494 mA h g(-1), has gained special attention as a promising anode material. Here, we report a self-assembled SnO2/Sn-reduced graphene oxide (rGO) sandwich nanocomposite developed by organometallic precursor coating and in situ transformation. Ultrafine SnO2 nanoparticles with an average diameter of 5 nm are sandwiched within the rGO/carbonaceous network, which not only greatly alleviates the volume changes upon lithiation and aggregation of SnO2 nanoparticles but also facilitates the charge transfer and reaction kinetics of SnO2 upon lithiation/delithiation. As a result, the SnO2/Sn-rGO nanocomposite exhibited a superior lithium storage capacity with a reversible capacity of 1307 mA h g(-1) at a current density of 80 mA g(-1) in the potential window of 0.01-2.5 V versus Li+/Li and showed a reversible capacity of 767 mA h g(-1) over 200 cycles at a current density of 400 mA g(-1). When cycling at a higher current density of 1600 mA g(-1), the SnO2/Sn-rGO nanocomposite showed a highly stable capacity of 449 mA g(-1) without obvious decay after 400 cycles.