Hollow MnFe₂O₄@C Graphene Absorbing Aerogels: Ultra-Broadband and Flexible Compression Resistance

Graphene-based aerogels have received substantial attention in the realm of effective electromagnetic wave absorption due to their lightweight qualities and unusual three-dimensional network structure. This work creates a Hollow MnFe₂O₄@ C/reduced graphene oxide (RGO)/polyimide (PI) composite aerogel by anchoring hollow ferrite@carbon particles onto graphene using a two-step hydrothermal process and freeze-drying. The electromagnetic properties are adjusted by adjusting the thickness of the carbon shell layer, managing the defect density within the aerogel, improving polarization loss, and enriching internal heterogeneous interfaces. This aerogel has a maximum effective absorption bandwidth of 7.70 GHz and a minimum reflection loss of -68.04 dB. Under volumetric deformation, the composite aerogel continues to perform exceptionally well in terms of absorption. Its maximum effective absorption bandwidths are 7.50 and 7.87 GHz, and its minimum reflection loss at 30% and 50% compression is -79.49 and -60.01 dB, respectively. The impedance mismatch disadvantage brought on by aerogel compression is offset by the synergistic improvement of absorption performance through several loss modes. This aerogel can also tolerate more complicated and demanding settings because it has certain compressive strength and flexibility, as well as fire resistance and thermal insulation. It offers a strong basis for multifunctional absorber material research.