The light weight and low thermal conductivity of ceramic aerogels make them attractive as heat barriers in harsh environments like those needed on spacecraft. But while aerogels made from nanoparticles can be good thermal insulators, they tend to be brittle, limiting their applications. Aerogels made from nanofibers are more flexible but struggle to perform as practical thermal insulators. Now, researchers at Donghua University have made a ceramic aerogel from both SiO2 nanofibers and nanoparticles. To make the new aerogel, the team starts with a SiO2 nanoparticle aerogel, grinds it up, and then mixes it with the nanofibers to form a hierarchical, cellular structure that is both flexible and resistant to heat and cold (ACS Appl. Mater. Interfaces 2019, DOI: 10.1021/acsami.9b10018). The researchers showed that a material consisting of 30% nanoparticle aerogel pieces by weight can withstand a butane blowtorch and a liquid-nitrogen bath while retaining its elasticity. The material can be compressed to 50% of its original size 1,000 times in a row and still bounce back. Fabricating the material is simple—researchers mix the components, pour the mixture into a mold, and freeze-cure it. Led by materials scientists Yang Si and Bin Ding, the team created a 50 cm-wide sheet of the new aerogel for its tests. The researchers envision the material being used in protective clothing for firefighters, pipe insulation, and space- and aircraft parts.