Exceptionally strong and damage-tolerant carbon aerogel composite with high thermal stability and insulation

Carbon aerogels are distinguished by a series of remarkable qualities, including ultralow density, low thermal conductivity, and high specific surface area; however, their low strength and inherent brittleness present a problem that severely constrains their application. Here a design strategy is proposed to overcome these shortcomings by synergistically carbonizing flexible organic fibers and aerogel matrix while elaborately engineering their interfacial bonding; the result is the creation of an ultra-strong, damage-tolerant carbon aerogel composite. The material exhibits a nanoporous carbon aerogel matrix reinforced by in situ-formed carbon fibers, featuring low residual stress and gradient atomic-scale bonding between the fibers and matrix. This structure imparts ultrahigh strength, with high specific strength normalized by density, all surpassing the benchmark properties of existing aerogels; it also displays exceptional fracture toughness with unprecedented stability in crack propagation. These attributes are further combined with excellent thermal stability and insulation, high-temperature mechanical properties, good machinability, and ease of large-scale production.