Ionic Structured Redox-Mediating Polymeric Sulfurs for Lithium–Sulfur Batteries

Abstract

Polymeric sulfur demonstrates immense capabilities as a promising active material for lithium–sulfur batteries (LSBs) owing to their ability to capture lithium polysulfides (LiPS) through the formation of covalent bonds. Herein, we demonstrate an ionic structured polymeric sulfur (IP-S) as a redox mediating matrix, which provides structural stability, an ionic conductive pathway, and a uniform distribution of active materials within the electrode. In particular, the cationic structure of IP-S was attributed to the facilitated LiPS conversion kinetics with the high utilization of sulfur. Consequently, the IP-S electrode delivered the high specific capacity of 1398.8 mAh g_sulfur^–1 with a low-capacity fading rate of 0.071% over 400 cycles. Moreover, with a high sulfur loading (6.87 mg_sulfur cm^–2), the IP-S electrode achieved a high initial capacity of 7.23 mAh cm^–2. Therefore, this work provides the rational design of ionic structured polymeric sulfur for high performance LSBs as well as the correlation between the ionic structure and the electrochemical property.