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Taking into consideration the frigid and thunderstorms, the flame retardancy and de-icing performance are simultaneously desiderated for some open-air key equipment, such as air fuselage and wind turbine blades. Here, inspired by the anti-reflection phenomenon of moth eyes and cicada wings, a multi-functionalized and biomimetic MXene@SnO 2 hierarchical nanostructure is prepared to effectively impart flame retardancy and solar de-icing performance to thermoplastic polyurethane (TPU) resin used widely as the finishing coat of protective materials of open-air equipment. Based on the catalytic effect and barrier function, the addition of hierarchical MXene@SnO 2 nanostructures also effectively decreases the release of heat and toxic smoke from PU resin, as confirmed by reductions of 50.5% and 33.1% in the peak heat release rate and smoke production rate, respectively. Due to the appropriate refractive index, the light reflection phenomenon is effectively suppressed, thus promoting solar absorption (∼90% at 0.4 mm film) and photo-thermal conversion (∼74.2 °C with simulated solar illumination of 1.0 kW/m2) in TPU-MXene@SnO 2 nanocomposites. Within the environment of −20 °C, the surface temperature of TPU-MXene@SnO 2 nanocomposites is still up to 32.7 °C and the surface ice pellet begins to melt at ∼40s, much earlier than 600s of pure TPU resin. In addition, the practical application of functionalized TPU nanocomposites is further improved by the higher mechanical properties, attributed to the strong interfacial interaction. Inspired by moth eyes and cicada wings, flame retardancy and solar de-icing performance are first integrated into polymer materials, thus effectively promoting their application in some extreme environments. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • The free switch of passive radiation cooling and solar thermal conversion is realized. • An average temperature drop of ∼5.62 °C is achieved under the hot environment. • A temperature increase of 28.3 °C is achieved under the cold environment. • The fire hazards of materials designed are suppressed significantly. Seasonable and spontaneous replacement approach of daytime radiative cooling to solar thermal conversion is challenging yet imperative for year-round thermal management materials. Meanwhile, the fire safety of thermal management materials is extremely important but often overlooked. Herein, we report a bio-inspired and fireproof aerogel presenting dynamically self-switchable ability of daytime radiative cooling and solar thermal conversion, composed of thermochromic microcapsules (TC), boron nitride nanosheets (BN), and bio-based materials (alginate and phytate). In hot environments, TC/BN composite aerogel shows solar reflectivity of 91.8 % and IR emissivity of 84.3 %, promoting heat radiation to outer space and achieving an average temperature drop of ∼5.62 °C. Attributed to the thermochromic mechanism, TC/BN composite aerogel can harvest visible light of 87 % in the solar spectrum to increase the material temperature by 28.3 °C, under an environment of −8.8 °C. Based on the EnergyPlus simulation, the employment of TC/BN composite aerogel contributes to decreasing the energy consumption of buildings in both hot and cold regions, including Cairo, Singapore, Alaska, Yakutsk, and so on. Besides, the peak values of heat release rate and total heat release during the combustion of TC/BN composite aerogels are significantly decreased by 70.6 % and 58.4 %, compared to those of TC composite aerogel. The produced protective char layer enhanced by BN nanosheets is capable of isolating the fire and suppressing the fire propagation, improving the fire safety of composite aerogels designed. The TC/BN composite aerogels provide a smart thermal regulation mode for radiative cooling and solar heating, overcome the problems from changing weather and environment, and significantly promote the practical application by enhanced fire safety. [ABSTRACT FROM AUTHOR]