3D Printed Templating of Spatially Curved Multiscale Graphene Aerogels for Ultra-Broadband Microwave Absorption

Developing lightweight electromagnetic wave absorbers with broadband attenuation remains challenging due to the intrinsic conflict between impedance matching and attenuation capacity. Although multiscale architectures offer a theoretical pathway to resolve this dilemma, their realization is constrained by conventional aerogel processing, particularly by limited molding precision and the difficulty in forming complex curved structures. Here, we report a 3D printing-assisted double-sacrificial templating strategy for fabricating multiscale hierarchically architected graphene aerogels (HAGAs), enabling high-fidelity shaping of spatially intricate curved geometries at a feature resolution of approximately 150 µm. This approach integrates macroscopic gradient gyroid topologies with microscopic aligned cellular networks, thereby reconciling the impedance-attenuation trade-off. Specifically, the gradient topology optimizes impedance matching, whereas the aligned skeleton promotes multiple reflections and conductive dissipation. The optimized gradient HAGA achieves an ultra-broad effective absorption bandwidth of 9.25 GHz and a minimum reflection loss (RL_min) of −62.42 dB at an ultra-low density of 13.82 mg cm⁻³. Compared with its unstructured counterpart (5.41 GHz and −12.16 dB), this architecture delivers a 70.98% bandwidth expansion and a 50.26 dB lower RL_min, alongside a 60% mass reduction. This work presents a scalable strategy for fabricating multiscale lightweight architectures with complex geometries, offering broad potential for stealth applications.