Microwave-Assisted Synthesis of Tin Sulfide/Reduced Graphene Oxide Nanocomposites As Anode Material for High-Performance Lithium-Ion Batteries

Rechargeable Lithium ion batteries (LIBs), as a great promise power source for next generation electric vehicles such as electric vehicles (EVs). Demands for batteries with higher energy density, better cycle performance, lower cost and more safety are increasing. Graphite is mostly used as anode material for the commercial Lithium ion batteries with the theoretical specific capacity 372 mAh g^-1 only. However, in order to overcome the lower capacity problem, many alternatives as anode materials are concerned including metals or metal sulfides.

Recently, tin-based materials (e.g. Sn, SnO₂, SnS) have been widely studied as anode materials because they have relatively high theoretical capacities, less toxic and low cost. In particular, tin sulfides has such as high theoretical capacity 782 mAhg¹.However, the great volume expansion and the agglomeration of particles for the tin sulfides during the charge/discharge process could possibly result in pulverization of the electrode and thus to lead to rapid decrease in capacity and poor cycle life.

Graphene or reduced graphene oxide (RGO), as one of the highly potential materials in lithium-ion batteries, is also used to be decorated with metal oxides or metal sulfides due to their high specific surface area, excellent electronic conductivity and porous structure. Therefore, an improved electrochemical performance can be achieved. More recently. Lots works have demonstrated that the incorporation of graphene within tin sulfide-graphene nanocomposites can provide a large area contact for tin sulfide particles and inhibit the volume change of tin sulfides, thus enhancing the electrochemical performance of tin sulfide-graphene nanocomposites.

Thus, in this work, SnS/RGO nanocomposites was synthesized via a facile microwave-assisted method. The physical and electrochemical properties of the as-prepared nanocomposites were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, cyclic voltammetry, galvanostatic charge/discharge tests and electrochemical impedance analysis. Indeed, the SnS nanoparticles were successfully decorated on the surface of RGO, and the resultant SnS/RGO nanocomposite demonstrated an improved electrochemical performance because the incorporation of RGO provided a large area contact for SnS nanoparticles and inhibited the volume change of SnS during charge/discharge process.