Sintering-Resistant Aerogel-Based Fire-Protective Coating Enabled by Interfacial Anchoring strategy for Battery Thermal Runaway Protection

Abstract

Aerogel-based fire-protective coatings are promising for lithium-ion battery thermal runaway protection owing to their lightweight and low thermal conductivity, yet their nanoporous networks are prone to high-temperature sintering, collapse, and insulation failure under flame ablation. Herein, a sintering-resistant aerogel-based fire-protective coating is developed via an interfacial anchoring and TiO₂-mediated interfacial stabilization strategy. In this coating, hollow Al₂O₃ microspheres provide a thermally stable framework and hollow heat barriers, while their surfaces anchor the aerogel network to suppress aggregation, coarsening, and pore collapse during ablation. Meanwhile, TiO₂ nanoparticles mediate high-temperature interfacial stabilization, further reinforcing the porous ceramic framework and improving ablation resistance. This cooperative structure interrupts the “sintering–collapse–insulation failure” degradation pathway and stabilizes the aerogel-derived insulation architecture. The coating exhibits a low thermal conductivity of 0.0463 W m⁻¹ K⁻¹. Under 836 °C flame exposure, a 2 mm coating maintains the cold-side temperature at ∼300 °C and remains crack-free after burning. After ablation, the coating retains electrical insulation with a leakage current of only 0.044 mA at 1500 V. In a practical battery fire test, the 2 mm coating reduces the cold-side temperature from 402 to 178 °C and suppresses the peak heat flux by more than fourfold, effectively inhibiting lithium-ion battery thermal runaway propagation and improving battery safety. This work offers a coating-centered strategy for lightweight fire-protective coatings with integrated thermal, fire, and electrical safety protection.