Synergistic hydrocarbon surfactant systems for thermal runaway suppression in lithium-ion batteries

This study investigates the development of eco-friendly foam extinguishing agents for suppressing thermal runaway (TR) fires in lithium-ion batteries (LIBs) by synergizing hydrocarbon surfactants. Three anionic surfactants—sodium α-alkenyl sulfonate (AOS), sodium dodecyl benzene sulfonate (SDBS), and sodium lauryl ethoxylate sulfate (SLES)—were compounded with amphoteric betaine (Bet) and nonionic alkyl polyglucoside (APG) to optimize foamability, stability, wettability, and fire suppression performance. Surface tension analysis, critical micelle concentration (CMC) measurements, and fire extinguishing tests were conducted to evaluate the physicochemical properties and mechanisms of these composite systems. Results demonstrated that Bet/SDBS and APG/SLES formulations exhibited superior synergistic effects, significantly reducing surface tension (e.g., Bet/SDBS: γ CMC  = 29.38 mN/m) and enhancing foamability, wettability and foam stability. In fire suppression tests, the 0.1 wt% Bet/0.1 wt% SDBS system achieved the fastest extinguishing time (0.21 s) and highest cooling rate (20.7 °C/s) by forming a dense foam layer that isolated oxygen and prolonged cooling. The study highlights the potential of hydrocarbon surfactant blends as sustainable alternatives to fluorocarbon-based agents, offering biodegradability, low toxicity, and high efficiency in LIB fire scenarios.