biostudies-literatureUnknown17(1)Tang WDeveloping high-efficient flame-retardant coatings is crucial for fire safety polymer and battery fields. Traditional intumescent coatings and ceramifiable coatings struggle to provide immediate and prolonged protection simultaneously, which limits the applicability. To address this, an innovative bi-layered coating with organic/nano-inorganic additives is inspired by differential response behaviors, enabling relay response effect with both fast-acting and extended protection. Specifically, two layers function continuously in the form of a relay. With a mere 320 microns, the bi-layered coating withstands fire temperatures of up to 1400 °C for at least 900 s. Consequently, the coating effective prevented burn through in aluminum plates and glass fabric-reinforced epoxy resin, which otherwisNano-micro letters231https://www.ebi.ac.uk/biostudies/studies/S-EPMC12031706biostudies-literatureBi-Layered, Ultrathin Coating Initiated Relay Response to Impart Superior Fire Resistance for Polymeric and Metallic Substrates.PMC12031706Prolongo SGQiu YLiu YChen QLi JWang DYAo XTang WQian LfalseBi-Layered, Ultrathin Coating Initiated Relay Response to Impart Superior Fire Resistance for Polymeric and Metallic Substrates.Developing high-efficient flame-retardant coatings is crucial for fire safety polymer and battery fields. Traditional intumescent coatings and ceramifiable coatings struggle to provide immediate and prolonged protection simultaneously, which limits the applicability. To address this, an innovative bi-layered coating with organic/nano-inorganic additives is inspired by differential response behaviors, enabling relay response effect with both fast-acting and extended protection. Specifically, two layers function continuously in the form of a relay. With a mere 320 microns, the bi-layered coating withstands fire temperatures of up to 1400 °C for at least 900 s. Consequently, the coating effective prevented burn through in aluminum plates and glass fabric-reinforced epoxy resin, which otherwis2025-01-01T00:00:00Z2025 Apr2026-03-27T16:44:43.933Z2025-07-03T03:04:14.921ZS-EPMC120317064027904810.1007/s40820-025-01739-8