Ultra-lightweight and multifunctional ionic liquid-modified graphene/polyimide aerogels for efficient electromagnetic wave absorption

In this work, 1-aminoethyl-3-methylimidazolium bromide ionic liquid was used to modify the surface of graphene nanosheets (GNs) through “π–π” interaction to achieve good dispersion and conductivity. By introducing ionic liquid-modified graphene nanosheets (IGNs) into the PI matrix, the ultra-lightweight and multifunctional IGNs/PI aerogels were prepared via freeze-drying and thermal imidization. Benefiting from the porous structure and the introduction of conductive IGNs, the IGNs/PI aerogels exhibit excellent electromagnetic wave (EMW) absorption properties, compression properties, thermal insulation properties and thermal stability. Notably, when the volume content of IGNs is 10%, the IGNs/PI-10 aerogels show the best EMW absorption performance with a minimum reflection loss (RL min ) of −24.8 dB at 2.44 mm and an effective absorption bandwidth (EAB) of 3.6 GHz at 3.00 mm. These promising characteristics including excellent EMW absorption, compression properties and thermal insulation endow IGNs/PI aerogels great application prospects as multifunctional EMW absorbers. Graphical Abstract