Aloe‐Derived Sustainable, Aqueous and Flame Retardant Binder Toward High‐Performance Li‐S Batteries

Abstract Lithium‐sulfur (Li‐S) batteries offer ultra‐high theoretical energy density (2600 Wh kg⁻¹) but face commercialization hurdles from polysulfide shuttling and sulfur flammability. A multifunctional biomass‐derived binder by modifying aloevera gel (AG) with phytic acid (PA) is designed for addressing these two issues. The AG‐PA binder provides strong mechanical integrity for the sulfur cathode and features N‐, O‐, and P‐rich polar groups that chemically anchor lithium polysulfides (LiPSs) and accelerate Li⁺ deposition. This enhances LiPSs redox kinetics and suppresses shuttling. Consequently, AG‐PA‐based Li‐S cells deliver a high initial capacity of 776.1 mAh g⁻¹ and retain 527.0 mAh g⁻¹ at 4 C (1 C = 1675 mA g⁻¹) after 1000 cycles (ultralow decay: 0.032% per cycle). Crucially, during combustion, heat decomposes AG‐PA's phosphorus groups, generating phosphoric acid and water vapor that form a physical barrier isolating oxygen/heat. Simultaneously, PO· radicals scavenge H·/HO· radicals, quenching chain reactions. This dual‐action significantly enhances safety. This work establishes a scalable biomass engineering approach to concurrently boost energy density, cyclability, and safety in Li‐S batteries, bridging gaps towards practical deployment.