Aqueous Supramolecular Binder for High-Performance Lithium–Sulfur Batteries

Developing an advanced electrode structure is highly important for obtaining lithium sulfur (Li-S) batteries with long life, low cost, and environmental friendliness. Some bottlenecks, such as large volume deformation and environmental pollution caused by the electrode preparation process, are still hindering the practical application of Li-S batteries. In this work, a new water-soluble, green, and environmentally friendly supramolecular binder (HUG) is successfully synthesized by modifying natural biopolymer (guar gum, GG) with HDI-UPy (cyanate containing pyrimidine groups). HUG can effectively resist electrode bulk deformation through a the unique three-dimensional nanonet-structure formed via covalent bonds and multiple hydrogen bonds. In addition, abundant polar groups of HUG have good adsorption properties for polysulfide and can inhibit the shuttle movement of polysulfide ions. Therefore, Li-S cell with HUG exhibits a high reversible capacity of 640 mAh g-1 after 200 cycles at 1C with a Coulombic efficiency of 99%.