Modified zirconia fiber/reduced graphene oxide composite aerogels with exceptional mechanical and microwave absorption properties for harsh-environment applications

The exploration of space is a global endeavor that demands sophisticated technologies and skills to ensure survival in harsh environments. Graphene aerogels have demonstrated great potential for thermal insulation and electromagnetic protection in the aerospace industry because of their low density, porous structure, and high dielectric properties. However, their weak mechanical properties are a severe limitation in harsh environments, hindering their diverse applications such as microwave absorption (MA). To address this issue, we prepared zirconia fiber (ZF)/reduced graphene oxide (rGO) composite aerogels through bidirectional freezing and subsequent thermal annealing. The resultant lamellar structure of the composite aerogels exhibits exceptional mechanical properties, such as high compressive deformation up to 90%, excellent cyclic compressibility, low thermal conductivity of 0.027 W center dot m(-1)center dot K-1, and superior MA performance with a minimum reflection loss (RLmin) of -72.2 dB at a thickness of 2.1 mm and an effective absorption bandwidth (EAB) of 8.4 GHz (9.6-18.0 GHz). Furthermore, the absorbing coatings based on modified ZF/rGO composite aerogels have significantly reduced radar cross-section by 22.94 dBsm. Consequently, the composite aerogels exhibit robust mechanical properties and excellent MA performance after high- and low-temperature treatments, showing high potential for advanced applications in space suits, spacecraft, and probes and so on.