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

ABSTRACT 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.