Superelastic Carbon Aerogels: An Emerging Material for Advanced Thermal Protection in Extreme Environments

Carbon aerogels (CAs) are desirable for thermal protection in aerospace because of their lightweight and high-temperature insulation characteristic; however, their intrinsic brittleness and flaw sensitivity easily trigger catastrophic failure when resisting high-frequency thermal shocks or complex mechanical stresses. Compression is the predominant load applied on aerogels by aerodynamic pressure and pre-tightening force; therefore, the structural elasticity and exceptional capability to keep thermal performance under impact stress are crucial in deciding the actual availability of aerogels. This review presents the recent progress in newly resilient CAs for thermal protection, focusing on reliable structural stability, thermal stability, and thermal superinsulation property. The influence law of microstructures on heat transfer behaviors is first investigated, followed by construction strategies for adiabatic CAs, emphasizing the recoverable deformability resulting from increased continuity of building blocks from 0D nanoparticles to 1D nanofibers/nanotubes and then to 2D nanosheets. Moreover, the optimization of thermal stability in high-temperature aerobic environments and thermal insulation performance are discussed. Finally, it raises current challenges and further opportunities for CAs toward better properties and brighter prospects.