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 degrees 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.