Dual-Crosslinked Aqueous Binder for High Sulfur Loading Lithium-Sulfur Batteries

High sulfur loading is essential for the practical application of lithium-sulfur (Li-S) batteries but is limited by severe polysulfide shuttling, large electrode volume changes, and sluggish Li⁺ transport. Herein, a dual-crosslinked binder (DCB) is constructed through hydrogen-bonding and ionic-pair interactions between quaternized soy protein isolate (QSPI) and poly (acrylic acid)-based LA133. The 3D crosslinked network enhances electrode mechanical integrity and adhesion, effectively alleviating structural degradation and volume variation during cycling. Meanwhile, abundant polar functional groups provide continuous Li⁺ coordination sites, and theoretical calculations reveal a hopping-mediated Li⁺ transport pathway between adjacent coordination sites, thereby promoting polysulfide conversion. As a result, the DCB simultaneously improves electrode stability and reaction kinetics. A 1.1 Ah Li-S pouch cell employing the DCB achieves a high energy density of 348 Wh kg^-1 and stable cycling over 60 cycles under practical conditions with a low electrolyte/sulfur ratio of 4 µL mg_s ^-1 and a low N/P ratio of 1.5. This work offers an effective dual-crosslinking strategy for regulating Li⁺ transport and enhancing electrode stability toward practical high-sulfur-loading Li-S batteries.