Improved infrared stealth and electromagnetic interference shielding performance of polyimide‐derived carbon aerogels by constructing heterogeneous nanopores

Abstract With the rapid development of science and technology, there is an increasing demand for lightweight materials with excellent electromagnetic interference (EMI) shielding and infrared stealth performance for space applications. In this study, a series of polyimide/silica (PI/SiO 2 ) aerogels were fabricated by blending, which were dried using supercritical CO 2 drying method. Then, PI/SiO 2 composite aerogels were carbonized to prepare carbon aerogels with superior thermal insulation and EMI shielding properties. The carbonized PI/SiO 2 aerogels contained mesopores which enhanced the interfacial thermal resistance and improved the thermal insulation performance by 69% when compared with those samples without SiO 2 . The presence of mesopores adjusted the impedance matching of carbon aerogels, which allowed more EM waves to enter inside of the aerogels and dissipate through multiple reflections, thereby achieving absorption‐dominant EMI shielding performance. This study proposed a viable approach to preparing PI‐based carbon aerogels with excellent infrared stealth and EMI shielding performance, which show promising applications in aerospace and related industries. Highlights The introduction of SiO 2 regulated the microstructure of carbon aerogels. The thermal conductivity of carbon aerogels reached as low as 0.10 W/mK with 3 wt% SiO 2 . The EMI performance of carbon aerogel was enhanced from 22.4 to 33.5 dB.