Spatial Segmentation and Controllable Connection Enabled Hollow Microsphere-Carbon Distributed RLC Networks for Multifunctional EM/Thermal Regulation

<title>Abstract</title> <p>Lightweight hierarchical porous composites for electromagnetic (EM) wave attenuation and thermal management face a common trade‑off: conductive networks needed for dissipation often ruin impedance matching. Here we resolve this by an ice‑templated heterogeneous nucleation strategy. Magnetic dual-shell hollow microspheres (DSHM) serve as ice‑nucleating agents, directing nitrogen‑doped carbon nanosheets (N-CNSs) to bridge the isolated microspheres without forming continuous conductive shells. The resulting architecture is a distributed resistive‑inductive-capacitive (RLC) network. The optimized aerogel achieves a reflection loss of − 54.86 dB and an effective absorption bandwidth of 6.56 GHz at only 8 wt% filler, together with a thermal conductivity of 0.0605 W·m⁻¹·K⁻¹ and &gt; 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 harming EM performance. This ice‑templated heterogeneous nucleation paradigm provides a generalizable route to program filler connectivity in carbon nanosheet networks for lightweight EM/thermal management.</p>