A facile complexing chemical reduction for the preparation of Sn/graphene nanocomposites and their high performance for lithium-ion batteries

The pursuit of simpler and more efficient methods for the preparation of high-performing lithium-storage materials is always considered to be an important job for researchers interested in lithium-ion batteries. Herein, a facile complexing chemical reduction strategy is successfully developed for the preparation of newly advanced Sn/graphene (Sn/G) nanocomposite as anode material LIBs. The complexing reagent of ethylenediamine tetraacetate disodium (EDTA-2Na) and reducing agent of NaBH4 added in the preparation process are both found to play pivotal roles in the controllable reduction of Sn2+ and formation of highly conductive graphene matrix. The Sn/G nanocomposite exhibits a loosely stacked structure with ultrafine Sn nanoparticles (20–40 nm) uniformly dispersing on graphene nanosheets. This specially designed morphology is proved to be beneficial for electrolyte infiltrating and highly efficient transport of Li-ions. The Sn/G nanocomposite displays outstanding lithium storage up to 1032 mAh g−1 after 150 cycles and a high rate performance of 535 mAh g−1 at 1 A g−1. The highly conductive and flexible network of graphene effectively alleviates the small absolute volume expansion of ultrafine Sn nanoparticles and maintains the structure stability. In addition, a fair low-temperature performance of 322 mAh g−1 at − 20 °C was also achieved due to the excellent structural features of the Sn/G nanocomposite. The work has managed to provide a simple and reliable method for the synthesis of Sn/C material as well as a potential candidate for low-temperature lithium storage applications.