In-situ covalent bonding of polysulfides with electrode binders in operando for lithium–sulfur batteries

Abstract

Dissolved polysulfides cause high self-discharge, low coulombic efficiency and short cycling life due to their shuttle effect in the charge/discharge cycles in lithium-sulfur (Li-S) batteries. Despite of various attempts (e.g., addition of metal oxides and chalcogenides in the cathode, immobilization of sulfur with various carbons, and confinement of sulfur within the cathode side with membranes) in solving this problem, it still remains a major challenge for Li-S batteries. Here, we demonstrate that chemically active binders can in situ bond to the polysulfides in the electrode. Besides the common binding functions of the cathode materials to the current collector, the covalent bonding between binders and polysulfides could bestow the higher capacity, stable cycling and high coulombic efficiency, even under the high loading of sulfur contents. Thus, this study provides an alternative and effective way in solving the shuttle effect of the dissolved lithium polysulfides for Li-S batteries.