Biomimetic root-soil-structured aerogel for synergistic thermal management and electromagnetic wave absorption

Addressing the dual demands of waste biomass recycling and the development of thin, high-performance microwave-absorbing multifunctional composites, this study proposes a biomimetic design strategy inspired by the natural root-soil architecture. This strategy enables the high-value utilisation of waste wool and the synergistic integration of thermal management and electromagnetic wave absorption within a single composite system. A three-dimensional supporting framework composed of phase-change fibres is constructed, mimicking the load-bearing root network embedded within soil. Through freeze-drying, a wool keratin (WK)/graphene oxide (GO) composite is in situ assembled, forming a soil-analogous aerogel matrix with pronounced mechanical interlocking. Subsequent incorporation of MXene, MWCNTs, and Fe₃O₄Fe₃O₄Fe₃O₄ nano-functional components mimics nutrient diffusion and uptake processes in natural soil-root systems, establishing a magneto-dielectric dual-loss network within the porous framework. Benefiting from the hierarchical porous architecture and synergistic loss mechanisms, the composite exhibits enhanced multiple scattering, internal reflection, and attenuation, resulting in broadband and highly efficient electromagnetic wave absorption.In the X-band, the aerogel achieves a minimum reflection loss (RL_min) of -43.34 dB at a thickness of only 1.8 mm, along with an effective absorption bandwidth (EAB, RL ≤ -10 dB) of 4.2 GHz. Concurrently, the composite exhibits effective thermal management capability, with a heat storage enthalpy exceeding 13 J. These results provide a viable pathway for high-value waste wool utilisation and open new avenues for the development of high-performance thermal-electromagnetic smart protective materials.