Multiscale structural design of heterostructured carbon/boron nitride aerogels for efficient thermal conductivity and broadband electromagnetic wave absorption

The integration of thermal conductivity into electromagnetic wave absorption (EWA) materials presents a compelling solution to address the dual challenges of electromagnetic radiation and heat accumulation issue in next-generation electronics. Here, we demonstrate a multiscale design strategy through architecting carbon/boron nitride (CBN) aerogels with a continuous three-dimension (3D) carbon framework at macroscopic scale and BN/C heterogeneous interfaces at microscopic scale. The BN/C interfaces generates enhanced interfacial polarization, endowing the CBN₂ powder/epoxy resin with a minimum reflection loss (RL_min) of −44.84 dB, an EAB of 4.8 GHz, and through-plane thermal conductivity of 0.81 W·m⁻¹·K⁻¹. Remarkably, the macroscopic-scale continuous 3D carbon skeleton can greatly promote the migration and uneven distribution of electrons at the microscopic-scale BN/C heterogeneous interface. As a consequence, the CBN₄ aerogel/epoxy resin (with an ultra-low filler of 7 wt%) yields an RL_min of −30.0 dB, and its through-plane and in-plane thermal conductivity of CBN₄-A is 0.66 and 1.67 W/m·K, respectively. Furthermore, the CBN₄ aerogel/epoxy resin metamaterial is further fabricated and its EAB can be as wide as 15.67 GHz. Therefore, this multiscale design paradigm establishes a new route for designing dual-functional material capable of simultaneous broadband electromagnetic energy dissipation and thermal management in advanced electronic systems.