Spatial segmentation and controllable connection enabled hollow microsphere-carbon distributed RLC networks for multifunctional EM/thermal regulation

Abstract Lightweight hierarchical porous composites for electromagnetic (EM) wave attenuation and thermal management face a common trade‑off: conductive networks required for energy dissipation often degrade impedance matching. Herein, a hierarchically organized composite aerogel (CNGA) is constructed through heterogeneous ice-templated assembly of double-shell hollow microspheres (DSHM) and nitrogen-doped carbon nanosheet (N-CNS) bridges. Within the proposed distributed RLC framework, the N-CNS bridges provide conductive pathways, while the spatially distributed DSHM introduce heterogeneous interfaces and localized electromagnetic loss, collectively contributing to a favorable balance between attenuation and impedance matching. The optimized aerogel achieves a reflection loss of –54.86 dB and an effective absorption bandwidth of 6.56 GHz at a filler loading of only 8 wt%, together with a thermal conductivity of 0.0605 W·m⁻ 1 ·K⁻ 1 and > 95% infrared absorptivity. Nitrogen doping (pyridinic/pyrrolic N) and nickel-induced graphitization of amorphous carbon enhance polarization and conduction losses, respectively. Resin infiltration further raises the compressive strength to 45.70 MPa without impairing EM performance. This work highlights a spatially regulated structure–property strategy for integrating electromagnetic attenuation, thermal insulation, and mechanical reinforcement in lightweight multifunctional composites.