Large-scale fabrication of reduced graphene oxide-sulfur composite films for flexible lithium-sulfur batteries

The rapid development of flexible electronic devices requires the design of flexible energy-storage devices. Lithium-sulfur (Li-S) batteries are attracting much interest due to their high energy density. Therefore, flexible Li-S batteries with high areal capacity are desired. Herein, we fabricated freestanding reduced graphene oxide-sulfur (RGO@S) composite films with a cross-linked structure using a blade coating technique, followed by a subsequent chemical reduction. The porous cross-linked structure endows the composite films with excellent electrochemical performance. The batteries based on RGO@S composite films could exhibit a high discharge capacity of 1381 mAh/g at 0.1 C and excellent cycle stability. Furthermore, the freestanding composite film possesses excellent conductivity and high mechanical strength. Therefore, they can be used as the cathodes of flexible Li-S batteries. As a proof of concept, soft-packaged Li-S batteries were assembled and remained stable electrochemical performance under different bending states. (C) 2019 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.