A facile synthesis of three dimensional graphene sponge composited with sulfur nanoparticles for flexible Li-S cathodes

Compared with a two dimensional graphene sheet, a three dimensional (3D) graphene sponge has a continuous conductive structure and numerous pores, which are beneficial for sulfur utilization and anchoring. However, strategies for the construction of 3D graphene sponges composited with sulfur nanoparticles (3DGS) are either energy consuming or involve toxic reagents. Herein, a 3DGS is fabricated via a reduction induced self-assembly method, which is simple but facile and scalable. The structural design of this 3DGS promises fast Li + transport, superior electrolyte absorbability and effective electrochemical redox reactions of sulfur. As a result, this 3DGS achieves a stable capacity of 580 mA h g −1 after 500 cycles at a high rate of 1.5 A g −1 , which corresponds to a low fading rate of 0.043% per cycle. The present study effectively demonstrates that the 3D construction strategy is propitious for obtaining flexible high performance Li-S batteries. A novel 3DGS was fabricated via a reduction induced self-assembly method. When used as a sulfur cathode, it shows high rate discharge capacity retention up to 500 cycles.