Leaf-Inspired Biomimetic Aerogels for Thermal Insulation in Extreme Environments

Aerogels hold promise for thermal protection in extreme environments and energy conservation in the building field. However, it is a great challenge to develop aerogels that possess lightweight, flame-retardant, and thermal insulation properties. Herein, inspired by the natural leaf structure, are successfully synthesized silica/chitosan/zirconia fiber composite aerogels (SCZs). The obtained SCZs feature a biomimetic design that mimics the epidermis, mesophyll, and veins of leaves. The bionic structure endows SCZs with low density, mechanical robustness, high-temperature dimensional stability, and low thermal conductivity. These properties are achieved by effectively impeding heat transfer and preventing structural collapse under localized stress. Moreover, the synergistic interactions among the components give the aerogels additional properties, including flame retardancy, radiative cooling, hydrophobicity, and so forth. This study not only presents versatile aerogels with thermal insulation and flame-retardant properties under extreme environments, but also proposes a simple, sustainable, and low-cost strategy for the preparation of biomimetic aerogels. The advancements provide a solid foundation for applications in thermal protection and energy saving.