3D-Printed Gradient-Porous MXene@mRGO@SiO₂ Microspheres/SiC Hybrid Elastomer for Broadband Electromagnetic Wave...

3D printing via direct ink writing (DIW) enables the precise fabrication of macroscale architectures for high-performance electromagnetic wave absorption elastomers (EMWAEs). However, achieving inks that combine excellent printability with superior electromagnetic and mechanical properties remains challenging. Here, a scalable fabrication strategy employing MXene@modified-RGO@SiO₂ microspheres synthesized through continuous spheroidization is presented. The incorporation of SiO₂ nanoparticles on the microsphere surface preserves the spherical morphology, enhances dispersion within the silicone elastomer matrix, and optimizes rheological behavior for stable DIW extrusion. Guided by electromagnetic simulations, three-layer gradient-porous structures is designed and printed that maximize interfacial polarization and multiple scattering effects. The resulting elastomers exhibit a minimum reflection loss (RL_min) of -44 dB and a maximum effective absorption bandwidth of 7.2 GHz at a thickness of only 3 mm. In addition to their outstanding electromagnetic performance, the printed materials demonstrate improved thermal conductivity and tensile strength, offering a multifunctional platform suitable for flexible and wearable electronic devices. This approach provides a simple, effective, and customizable route for integrating advanced fillers into 3D-printable elastomers, paving the way for next-generation EMWAEs with tunable architectures, broad bandwidth absorption, and mechanical robustness.