Single-walled carbon nanotube gutter layer supported ultrathin zwitterionic microporous polymer membrane for high-performance lithium-sulfur battery

• Published in: Journal of colloid and interface science Vol. 628; pp. 1012 - 1022
• Main Authors: Sun, Shuzheng, Han, Lu, Hou, Jingjing, Yang, Yanqin, Yue, Junbo, Gu, Guoxian, Chuah, Chong Yang, Li, Jingde, Zhang, Zisheng
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 15-12-2022
• Subjects: Lithium-sulfur battery; Polymers of intrinsic microporosity; Separator modification; Single-walled carbon nanotubes; Zwitterion; Separator modification; Zwitterion; Polymers of intrinsic microporosity; Lithium-sulfur battery; Single-walled carbon nanotubes
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2022.08.025

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•A novel zwitterionic microporous polymer TB-BAA is successfully prepared.•Single-walled carbon nanotube (SWCNT) film is fabricated as a gutter layer.•TB-BAA/SWCNT/PP composite separator is made by spin-coating of TB-BAA on SWCNT/PP.•This separator can allow fast Li+ transfer but obstruct polysulfide permeation.•The resultant Li-S battery shows high cyclability and decent rate performance.
Development of efficient lithium-sulfur (Li-S) battery requires the need to develop an appropriate functional separator that allows strong facilitation and transport of lithium ions together with limited passage of polysulfides. In this work, a multifunctional separator (TB-BAA/SWCNT/PP) is developed through spin coating of a novel zwitterionic microporous polymer (TB-BAA) on the gutter layer constructed from single-walled carbon nanotubes (SWCNT), where commercially available polypropylene (PP) separator is used to act as the mechanical support. SWCNT in this study serves as the first modification layer to decrease the size of the macropores in the PP separator, while the ultrathin TB-BAA top barrier layer with the presence of zwitterionic side chains allows the creation of confined ionic channels with both lithiophilic and sulfophilic groups. Due to the presence of available chemical interactions with lithium polysulfides, selective ion transport can be foreseen through such separator. In this regard, shuttle effect that is frequently encountered in Li-S battery can be suppressed effectively via implementing the as-obtained functional separator, resulting in the creation of credible and stable sulfur electrochemistry. The TB-BAA/SWCNT/PP-based Li-S battery has been investigated to possess high cycling ability (capacity fading per cycle of 0.055% over 500 cycles at 1 C) together with decent rate capability (736.6 mAh g−1 at 3 C). In addition, a high areal capacity retention of 5.03 mAh cm−2 after 50 cycles can be also obtained under raised sulfur loading (5.4 mg cm−2).