Viologen-based ionic conjugated mesoporous polymer as the electron conveyer for efficient polysulfide trapping and conversion

• Published in: Science bulletin (Beijing) 2024-04, Vol.69 (8), p.1071-1080
• Main Authors: Li, Hai-Yang, Li, Zhong-Shan, Qiu, Gang-Hao, Zhang, Rou-Rou, Wang, Ya-Rui, Wang, Feng, Huang, Ren-Wu, Liu, Xiao-Fei, Zang, Shuang-Quan
• Format: Article
• Language: English
• Subjects: Conjugated mesoporous polymer; Lithium-sulfur battery; Polysulfide; Shuttle effect; Viologen
• ISSN: 2095-9273
• DOI: 10.1016/j.scib.2024.01.016

The viologen component with redox activity in the ionic CMP serves as an electronic pump for donating electrons to and accepting electrons from sulfur species, which can facilitate the conversion of both solid lithium sulfide and soluble polysulfides. [Display omitted] The commercialization of lithium-sulfur (Li-S) batteries has been hindered by the shuttle effect and sluggish redox kinetics of lithium polysulfides (LiPSs). Herein, we reported a viologen-based ionic conjugated mesoporous polymer (TpV-Cl), which acts as the cathode host for modifying Li-S batteries. The viologen component serves as a reversible electron conveyer, leading to a comprehensive enhancement in the adsorption of polysulfides and improved conversion rate of polysulfides during the electrochemical process. As a result, the S@TpV-PS cathode exhibits outstanding cycling performance, achieving 300 cycles at 2.0 C (1 C = 1675 mA g−1) with low decay rate of 0.032% per cycle. Even at a high sulfur loading of 4.0 mg cm−2, S@TpV-PS shows excellent cycling stability with a Coulombic efficiency of up to 98%. These results highlight the significant potential of S@TpV-PS in developing high-performance Li-S batteries.