A Multiscale-Designed Ceramic Nanofiber Aerogel with High-Temperature Mechanical Superelasticity and Thermal Superinsulation

Thermal insulation in extreme environments, such as aerospace, geothermal settings, and thermoelectric applications, demands materials with excellent structural stability and outstanding thermal insulation capabilities. Ceramic nanofiber aerogels have contributed to overcoming the mechanical limitations, such as the high brittleness of ceramic aerogels based on zero-dimensional building blocks, while further advancing lightweight structural design. However, most reported aerogels still suffer from limited elastic compressibility, insufficient structural stability, and weak thermal insulation performance at high temperatures even with the adoption of anisotropic structural designs. Here, we report a ceramic nanofiber aerogel with a microscale multiply folded structure and a nanoscale core-shell morphology, featuring an incompletely crystallized outer SiO2 layer. In addition to possessing the fundamental advantages of previously reported ceramic nanofiber aerogels, this material demonstrates significant breakthroughs in mechanical strength, fatigue resistance under large deformations, structural stability, and high-temperature thermal insulation capabilities. It offers a highly attractive materials system for robust thermal insulation in extreme environments.