Superstrong Lightweight Aerogel with Supercontinuous Layer by Surface Reaction

Abstract

Breaking the thermal, mechanical and lightweight performance limit of aerogels has pivotal significance on thermal protection, new energy utilization, high-temperature catalysis, structural engineering, and physics, but is severely limited by the serious discrete characteristics between grain boundary and nano-units interfaces. Herein, a thermodynamically driven surface reaction and confined crystallization process is reported to synthesize a centimeter-scale supercontinuous ZrO₂ nanolayer on ZrO₂-SiO₂ fiber aerogel surface, which significantly improved its thermal and mechanical properties with density almost unchanged (≈26 mg cm⁻³). Systematic structure analysis confirms that the supercontinuous layer achieves a close connection between grains and fibers through Zr─O─Si bonds. The as-prepared aerogel exhibits record-breaking specific strength (≈84615 N m kg⁻¹, can support up to ≈227 272 times aerogel mass) and dynamic impact resistance (withstanding impacts up to 500 times aerogel mass and up to 200 cycling stability at 80% strain). Besides, its temperature resistance has also been greatly optimized (400 °C enhancement, stability at 1500 °C). This work will provide a new perspective for exploring the limits of lightweight, high strength, and thermal properties of solid materials.