Graphene/Polyimide Composite Aerogels for Superior Electromagnetic-Wave-Absorbing Materials with High Thermal Stability and Absorption Effectiveness

Graphene/polyimide composite aerogels (GPIs) were fabricated through a one-pot solvothermal method and then underwent heat treatment at 350 °C to obtain GPIs (350). GPIs (350) exhibits prominent electromagnetic-wave-absorbing properties. Specifically, the minimum reflection loss can reach −75.90 dB with a thickness of 3.75 mm, and the effective absorption bandwidth reaches 6.44 GHz with a thickness of 2.70 mm. The actual dosage of graphene oxide in the GPIs (350) absorbers is low to 3 wt %, showing high effectiveness in absorbing electromagnetic waves. Notably, GPIs (350) also displays excellent thermal stability up to 415 °C. Polyimide is proven to tune the electromagnetic properties and provide much graphene–polyimide interface. The composition of graphene and polyimide, the three-dimensional morphology, and post-heat treatment are the perfect match to guarantee excellent comprehensive electromagnetic wave absorption properties. The present work provides a much more facile and effective approach to fabricating electromagnetic-wave-absorbing materials with exceptional properties through tuning engineering polymers.