Reduced graphene oxide participation enabling fast nano-homogeneous deposition of sulfur for lithium–sulfur battery cathode

We present a facile, rapid, and gentle approach to synthesize a cathode for lithium-sulfur batteries utilizing reduced graphene oxide (rGO). The rGO sheets are introduced into a supersaturated sulfur solution, resulting in the uniform crystallization of sulfur nanoparticles on the rGO sheets. This process also effectively inhibits the shrinking and stacking of the rGO sheets. Thus, it is possible to achieve adequate utilization of sulfur during the charge/discharge process even when the sulfur mass ratio is high at 70%. Meanwhile, the physical adsorption effect of the host material is fully aroused, resulting in a favorable cycle life of 76.87% capacity retention after 400 cycles at 0.5C. The synthesized material exhibits remarkable homogeneity and electrochemical performance with great potential for practical applications, reaching the forefront of lithium-sulfur (Li–S) battery cathodes utilizing rGO as a host material without metal compounds or heteroatom doping. This approach holds great promise for the loading of sulfur in rGO-based Li–S battery. Sulfur nanoparticles can distribute evenly on the rGO sheets by a facile synthesis method. The pure rGO sheets together with carbon fibers and conductive carbon construct an effective conductive path. A nearly theoretical specific capacity of 1669.1 mAh g−1 at 0.1C and relatively low decay rate of 0.058% per cycle at 0.5C is obtained at high sulfur content of 70% based on the whole cathode. [Display omitted] •S@rGO-rGO and S@rGO cathodes were synthesized by a facile approach.•The S@rGO-rGO cathode possesses a high specific capacity of 1669.1 mAh g−1.•The LSB based on the S@rGO-rGO cathode shows a favorable cycle life of 76.87% capacity retention after 400 cycles.•The pouch cell could sustain a continuous discharge at 1 mA for over 2500 h.