Sustainable CoFe-Doped Biomass Carbon Aerogels for Ultra-Broadband Electromagnetic Absorption and Thermal Management

The synergistic coupling mechanism between magnetic and dielectric losses is widely recognized as a key design strategy for realizing efficient microwave attenuation composites. In this work, a carbon-based magnetic aerogel was successfully prepared using eggplant as a carbon source, realizing the interaction between magnetism and dielectric dissipation and developing a low-cost and environmentally friendly multifunctional material. The electromagnetic microwave absorption (EMA) characteristics were precisely tuned by varying the metal ion concentration ratio. Notably, the bimetallic ion-doped carbon aerogel has excellent EMA properties, with an EAB_maxof 6.32 GHz and RL_minvalue of −65.8 dB, under the condition of Fe³⁺and Co²⁺in a 1:2 molar proportion. This excellent performance is attributed to its unique three-dimensional (3D) carbon skeleton, in which the alloy nanoparticles are embedded in the hole-and-sheet structure and decorated on carbon, attaining optimal impedance alignment and enhanced wave dissipation performance. The combination of extremely low density and excellent compressive recovery properties, which can withstand multiple cycles of compression, has strongly advanced the field of biomass aerogels. This multifunctional aerogel material, which combines high EMA efficiency, environmental protection, low cost, thermal management, and compression resistance, has promising application in various electronic devices and military applications.