Synthesis of SnO2/graphene composite anode materials for lithium-ion batteries

Abstract

A tin dioxide/reduced graphene oxide composite (SnO2/RGO) is synthesized using combined methods, including in-situ metal tin reduction, spray drying and thermal treatment. Under mild hydrothermal condition, metal tin works as both reducing agent for few-layered graphene oxide (GO) to prepare restacked 2-dimensional (2D) reduced graphene oxide (RGO) sheets and metal source for homogeneously distributed nanostructured Sn and Sn oxides (Sn/SnO/SnO2). The 2D precursors are shrunk to a micro-sized dried blueberry shape via a spray drying process. After further thermal treatment, SnO2/RGO composite is obtained, in which Sn and SnO species are converted to SnO2 and the nano-sized SnO2 is well stabilized by the micro-sized 3D porous RGO supporting framework. The 3D SnO2/RGO composite exhibits not only a higher reversible capacity of 708 mAh·g−1 under a current density of 500 mA·g−1 over 150 cycles compared with 2D counterpart, but also a long and stable cycling life under a high current density of 1000 mA·g−1. This synthesis route can be considered as simple, economic and environmental-friendly, and it has great potential to find applications in other fields.