Issue

Vol. 17 (2025)

Bi-Layered, Ultrathin Coating Initiated Relay Response to Impart Superior Fire Resistance for Polymeric and Metallic Substrates

https://doi.org/10.1007/s40820-025-01739-8
Wei Tang
IMDEA Materials Institute, C Eric Kandel 2, 28906 Madrid, Spain
Qi Chen
IMDEA Materials Institute, C Eric Kandel 2, 28906 Madrid, Spain
Junxiao Li
College of Light Industry Science and Engineering, Beijing Technology and Business University, Fucheng Road 11, Beijing 100048, People’s Republic of China
Xiang Ao
IMDEA Materials Institute, C Eric Kandel 2, 28906 Madrid, Spain
Yunhuan Liu
IMDEA Materials Institute, C Eric Kandel 2, 28906 Madrid, Spain
Lijun Qian
College of Light Industry Science and Engineering, Beijing Technology and Business University, Fucheng Road 11, Beijing 100048, People’s Republic of China
Silvia González Prolongo
Materials Science and Engineering Area, Escuela Superior de Ciencias Experimentales y Tecnología, Universidad Rey Juan Carlos, Calle Tulipán s/n, 28933 Móstoles, Madrid, Spain
Yong Qiu
College of Light Industry Science and Engineering, Beijing Technology and Business University, Fucheng Road 11, Beijing 100048, People’s Republic of China
De‑Yi Wang
IMDEA Materials Institute, C Eric Kandel 2, 28906 Madrid, Spain

Corresponding Author: De‑Yi Wang

deyi.wang@imdea.org

Nano-Micro Letters, Vol. 17 (2025), Article Number: 231

Abstract

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 otherwise were burned through in 135 and 173 s, respectively. Meanwhile, the bi-layered coating suppressed the formation and decomposition of solid interface layer in lithium soft-package batteries, leading to prolonged electrochemical stability and fire safety. Additionally, the bi-layered coating with a fast response endows polyurethane foam with rapid self-extinguishing, preventing ignition even under exposure to strong fire of 1400 °C. Shortly, our work offers new insights into the design and development of thin, high-performance, and multi-application flame-retardant coatings.


Highlights:
1 Relay response of bi-layered coating achieved fast response and extended protection.
2 320-µm coating achieved over 900 s of burn-through resistance.
3 320-µm coating achieved extended electrochemical stability for battery under fire.

Keywords

Flame retardant Coating Ultra-thin Relay response Battery cases
Tang, Wei, Qi Chen, Junxiao Li, Xiang Ao, Yunhuan Liu, Lijun Qian, Silvia González Prolongo, Yong Qiu, and De‑Yi Wang. 2025. “Bi-Layered, Ultrathin Coating Initiated Relay Response to Impart Superior Fire Resistance for Polymeric and Metallic Substrates”. Nano-Micro Letters 17 (April):231. https://doi.org/10.1007/s40820-025-01739-8.
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