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

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.