Novel Sulfur-Containing Polymeric Cathode Material Prepared via an Inverse Vulcanization Method for Advanced Lithium–Sulfur Batteries

Abstract

Lithium–sulfur (Li–S) batteries have been the research hotspot of next-generation energy storage technology in recent years due to their high theoretical specific capacity, safety, and cost-effectiveness. However, inevitable lithium polysulfide intermediates’ dissolution and migration severely hamper their energy density and calendar life. Therefore, it is of significance to restrain the inevitable polysulfide shuttle effect in electrolytes. Herein, a new type of sulfur-containing polymeric cathode, poly(vinyl trimethoxysilane-co-sulfur) (PVTS), is successfully synthesized by an inverse vulcanization method to solve the polysulfide problem. The well-designed sulfur-containing polymer endows the Li–S battery with better performance, which has several features that are discussed below. First, the covalent bonding of the sulfur atom and the carbon atom of vinyl trimethoxysilane in PVTS effectually limits the polysulfide diffusion and further lessens the polysulfide dissolution, thereby preventing the loss of active materials. Second, a good liquid electrolyte wettability is conducive to the electrochemical reaction at the electrode/electrolyte interface. In the end, a faster charge transfer rate and a favorable lithiation/delithiation kinetics facilitate the electrochemical process. Accordingly, the PVTS/C cathode shows significantly enhanced cycling stability after 500 cycles and excellent rate performance.