A lightweight and high compressive resistance thermal insulation material with dual-network structure

Ceramic fibrous aerogels are highly desirable for thermal management materials due to their high porosity, excellent elasticity, thermal conductivity, and good thermal resistance. However, the fabrication of nanofibrous aerogel with super-elasticity and good shape retention at the same time has remained challenging. To meet the requirements, a novel anisotropy nanofibrous-granular aerogel with a quasi-layered multi-arch-like and hierarchical-cellular structure is designed and prepared by vacuum-filtration-assisted freeze-drying and sintering. The quasi-layered multi-arch and flexible nanofibers endowed the aerogels with excellent mechanical robustness (ultimate stress up to 60 kPa with strain 60%) and super-elasticity with recoverable compression strain up to 60%. The introduced SiO₂ aerogel nanoparticles and nanofibers are assembled into an arch-like structure and become the connection point of adjacent nanofibers, which endows low thermal conductivity (0.024 mW/(mK)) of composite aerogel. This novel strategy provides a fresh perspective for the preparation of nanofibrous aerogel with robust mechanical in thermal insulation and other fields.