One-pot in situ chemical reduction of graphene oxide and recombination of sulphur as a cathode material for a Li–S battery

Abstract

Li–S batteries with a high theoretical specific capacity and energy density are poised to be one of the most promising next generation systems; however, the complex preparation process of the cathode material and low cyclic stability, particularly at high current density, have limited their practical applications. Herein, we report a facile and eco-friendly one-pot strategy for the chemical reduction of graphene oxide and recombination of sulphur as the cathode material for a Li–S battery. The optimized rGO/S-3 composite material possesses a porous morphology with pore walls made of the rGO and sulphur composite. The sulphur content is about 73.5 wt%, the particle size is about 8–15 nm, and the particles are distributed evenly on the layer of rGO, wherein the thickness of rGO is about 3–4 nm, corresponding to 8–10 monolayer graphenes. The rGO/S-3 composite electrode presents a high initial discharge capacity of 1012 and 474 mA h g⁻¹ at 1C and 10C, respectively. The discharge capacity of 451 mA h g⁻¹ was preserved after 1200 cycles at 1C. Even though the current density increased to 10C, a discharge capacity of 237 mA h g⁻¹ may be obtained after 400 cycles.