Decoupling ambient stability from thermal responsiveness in thermoresponsive electrolytes via kinetic regulation

Thermoresponsive electrolytes offer a promising route toward safe lithium-ion batteries by rapidly solidifying under thermal abuse conditions. However, their practical implementation is fundamentally hindered by the intrinsic conflict between rapid thermal responsiveness and long-term ambient stability, because highly reactive polymerization systems are inherently susceptible to spontaneous gelation during storage. Here, we report a kinetically regulated thermoresponsive electrolyte that decouples ambient stability from high-temperature responsiveness through radical-quenching chemistry. By introducing hydroquinone monomethyl ether as an efficient radical scavenger into a benzoyl peroxide-initiated bismaleimide system, spontaneous polymerization is effectively suppressed under normal conditions while high-temperature responsiveness remains preserved. The electrolyte remains stable for over 6 months at room temperature and more than 1 month at 45°C without detectable gelation, yet still completes thermal solidification within 5 min at 140°C. Importantly, the electrolyte maintains good electrochemical compatibility with both LiFePO 4 cathodes and graphite anodes, enabling Ah-level pouch cells with 92.2% capacity retention after 300 cycles. Upon thermal triggering, the electrolyte rapidly forms an ion-blocking polymerized phase that suppresses internal short circuit and thermal runaway propagation. This work establishes kinetic regulation as an effective strategy for practical thermoresponsive battery electrolytes with simultaneously enhanced stability and safety.