Dome-celled aerogels with ultrahigh-temperature superelasticity over 2273 K.

Aerogels are known for their high porosity and very low density and can be made from a range of materials, but are limited by structural instability under extreme thermomechanical conditions. We report on 194 types of dome-celled ultralight aerogels that maintain superior elasticity spanning from 4.2 kelvin (K) to 2273 K, realized by a two-dimensional channel–confined chemistry method. Such aerogels exhibit superelasticity under 99% strain for 20,000 cycles and thermal shock resistance at 2273 K over 100 cycles. The high-entropy carbide aerogel achieves a thermal conductivity of 53.4 mW·m−1·K−1 at 1273 K and 171.1 mW·m−1·K−1 at 2273 K. The combination of temperature-invariant elasticity and chemical diversity makes such aerogels highly promising for extreme thermomechanics, from heat-insulated industries to deep space exploration. Editor's summary: Aerogels, which are typically made using a sol-gel process, consist of a group of materials with high porosity, near transparency, and ultralow density, as they can be up to 99% empty space. Pang et al. developed a two-dimensional channel–confined method to make dome-celled aerogels from a wide range of oxides, carbides, metals, and even high-entropy mixtures. The dome shape imbues the aerogels with mechanical and thermal robustness, allowing them to undergo thousands of compressive cycles up to 99% strain and wide-temperature-change thermal shock. Many of the carbides also have very low thermal conductivity even at high temperatures. —Marc S. Lavine [ABSTRACT FROM AUTHOR]