Improved lithium-ion and electrically conductive sulfur cathode for all-solid-state lithium–sulfur batteries

Abstract

The development of all-solid-state lithium–sulfur (Li–S) batteries is a promising way to solve the problems of sulfur dissolution and shuttling. Herein, a carbon matrix (GO–PEG) consisting of a lithium ion conductor (PEG) is synthesized by grafting PEG onto the surface of graphene oxide (GO) via an esterification reaction. Sulfur is in situ precipitated onto the surface of GO–PEG to form GO–PEG@C/S cathode materials in a one-pot reaction. The GO–PEG@C/S cathode materials show uniform distribution of sulfur nanoparticles on ionically and electrically conductive nanosheets. When the cathode is fabricated into an all-solid-state lithium–sulfur battery with a solid polymer electrolyte, the battery exhibits a high initial discharge capacity of 1225 mA h g⁻¹ at 0.2C (80 °C) and good cycling stability with a capacity retention of 86.6% after 100 discharge–charge cycles at 2C and 80 °C. These results demonstrate that the introduction of a lithium ion conductor into the matrix skeleton of the sulfur cathode can enhance the comprehensive electrochemical properties of all-solid-state Li–S batteries.