Three-dimensional thermally conductive structural materials enabled by dual-network design in aramid/boron nitride papers

Efforts to enhance thermal conductivity have largely been confined to functional composites and films, while the need for efficient heat propagation in mechanically loaded structures remains less explored. Here, we fabricate a thermally conductive honeycomb by constructing a dual-network architecture within aramid paper, where post-impregnated boron nitride nanosheets form interconnected thermal pathways while the fibrous scaffold maintains mechanical integrity. The composite paper reaches ∼6.82 W m−1 K−1 in-plane conductivity, ∼70 MPa tensile strength, and dielectric loss as low as ∼0.0062. In honeycomb form, it delivers ∼64% higher thermal conductivity and ∼95% faster heat spreading than pristine aramid honeycomb, offering a practical structural solution for thermal management.