An eco-friendly composite binder with robust network and strong affinity for long-lifespan high-loading Li-S batteries

• Published in: Chemical engineering science 2023-12, Vol.282, p.119294, Article 119294
• Main Authors: Wang, Fanghui, Wan, Jiajun, Liu, Jie, Wang, Rongfang, Wang, Lei
• Format: Article
• Language: English
• Subjects: High loading; Li-S battery; Long lifespan; Polymer binder
• ISSN: 0009-2509
• DOI: 10.1016/j.ces.2023.119294

•A water-based network binder combining robust mechanical property and strong affinity has been constructed.•LSO, rich in abundant strong polar bonds, can not only effectively adsorb polysulfides but also firmly connect TPG biopolymer chains.•An impressive long lifespan of 200 cycles at 0.2C has been achieved, under a high loading of 5.4 mg cm−2. To achieve practical high energy density of Li-S battery, it is crucial to construct high-loading sulfur electrodes. However, the poor mechanical stability and severe shuttle effect of high-loading sulfur cathodes during cycling limit the cycling stability. Herein, a mechanically robust network binder with strong affinity towards polysulfides has been designed to stabilize the high-loading sulfur electrode. Lithium polysilicate (LSO) possesses abundant strong polar Si-O and Si = O bonds, which not only can effectively adsorb polysulfides but also firmly connect tamarind polysaccharide gum (TPG) biopolymer chains. As a result, the c-LSO-TPG binder can efficiently maintain the integrity of high-loading sulfur cathode and suppress the polysulfide shuttling during cycling. In particular, under a high sulfur loading of 5.4 mg cm−2, the sulfur electrode can run 200 cycles steadily, delivering an areal capacity of 2.7 mAh cm−2. This provides a new avenue for the research and development of robust binders for high-loading and long-lifespan Li-S batteries.