A Self-regulatory organosulfur copolymer cathode towards high performance lithium-sulfur batteries

Abstract

Lithium–sulfur (Li−S) batteries are one of the most promising energy storage systems, in which the rational adsorption of soluble lithium polysulfides is critical for long cycling stability. Introducing organic groups through inner regulation on sulfur cathodes is a promising approach to manage the redox activity of lithium polysulfides. Herein, a zwitterionic framework is integrated into the redox–active sulfur chains to form a self–regulatory zwitterionic organosulfur copolymer (ZI-OS) cathode, which can establish a dynamic polysulfide–interception mechanism. Due to the sulfophilicity of imidazolium cations and lithiophilicity of sulfonate anions covalently attached to the zwitterionic framework, it can simultaneously immobilize polysulfides and improve Li+ transport. Consequently, the ZI-OS cathodes show outstanding rate capability and cycling stability. This work demonstrates a polysulfide-shuttle-suppression strategy to facilitate the utilization of polysulfides in self–regulatory sulfur cathodes; and put forward insights into the exploration of functional organosulfur copolymers for high–performance Li−S batteries.