Three-dimensional (3D) printed graphene aerogels have potential in electromagnetic wave absorption (EWA) engineering due to their ultra-low density, excellent electromagnetic dissipation, and the flexibility and precision of the manufacturing strategy. However, their high conductivity leads to severe impedance mismatch, limiting the performance of EWA. The demand for 3D printing also limits the dielectric properties of printable graphene inks, hindering the integration of high-performance absorbers with advanced manufacturing. This study proposes a multi-scale control strategy for 3D porous graphene oxide (GO) aerogels mediated by polyacrylic acid (PAA) gels. Precise control of the gel content enables dual-gradient regulation of the rheology (favoring direct ink writing DIW) and dielectric loss (enhancing EWA) of the GO/PAA composite materials, and reduces the aerogel density (6.9 mg cm−3) from 28.2 mg cm−3). Thermal reduction decomposes PAA into amorphous carbon nanoparticles anchored on reduced graphene oxide (rGO), enhancing impedance matching and absorption through synergistic 0D/2D interface polarization and conductive loss. The optimized rGO/PAA aerogel achieves a minimum reflection loss (RL) of −39.86 dB at 2.5 mm, with an effective absorption bandwidth (EAB) of 8.36 GHz (9.64–18 GHz) at 3.2 mm. Combined with DIW and this aerogel, we designed a metamaterial absorber (MA) with dual materials (dielectric loss) and structural gradients. This MA exhibits an ultra-wide EAB of 14 GHz (4–18 GHz) with a total thickness of 7.8 mm. This work establishes a "composition-structure-performance" coupling design paradigm, providing an engineering solution for developing lightweight broadband EWA materials. This research was published in Nano-Micro Letters under the title "Multiscale Design of Dual-Gradient Metamaterials Using Gel-Mediated 3D-Printed Graphene Aerogels for Broadband Electromagnetic Absorption".
Reference Information:
DOI: 10.1007/s40820-025-02005-7