Ten-Minute Synthesis of a New Redox-Active Aqueous Binder for Flame-Retardant Li-S Batteries

As a critical role in battery systems, polymer binders have been shown to efficiently suppress the lithium polysulfide shuttling and accommodate volume changes in recent years. However, preparation processes and safety, as the key criterions for Li-S batteries’ practical applications, still attract less attention. Herein, an aqueous multifunction binder (named PEI-TIC) is prepared via an easy and fast epoxy-amine ring-opening reaction (10 min), which can not only give the sulfur cathode a stable mechanical property, a strong chemical adsorption and catalytic conversion ability, but also a fire safety improvement. The Li-S batteries based on the PEI-TIC binder display a high discharge capacity (1297.8 mAh g⁻¹), superior rate performance (823.0 mAh g⁻¹ at 2 C), and an ultralow capacity decay rate of 0.035% over more than 800 cycles. Even under 7.1 mg cm⁻² S-loaded, the PEI-TIC electrode can also achieve a high areal capacity of 7.2 mA h g⁻¹ and excellent cycling stability, confirming its application potential. Moreover, it is also noted that TG-FTIR test is performed for the first time to explore the flame-retardant mechanism of polymer binders. This work provides an economically and environmentally friendly binder for the practical application and inspires the exploration of the flame-retardant mechanism of all electrode components.