Multifunctional PANI–TiO₂–Fe₃O₄@Attapulgite 3D Composite for Synergistic Microwave Absorption and Corrosion Protection

Electromagnetic (EM) pollution has emerged as a pressing concern, driving the demand for high-performance microwave absorbing materials. In this work, attapulgite (ATP) was employed as a natural, porous scaffold for the in situ integration of amorphous TiO2, Fe3O4, and polyaniline (PANI), constructing a multifunctional composite with tailored dielectric and magnetic properties. The TiO2 and PANI coatings not only induced strong interfacial and conduction polarization but also formed a continuous 3D conductive network, enabling efficient energy dissipation. Benefiting from the magneto-electric synergy among PANI, TiO2, and Fe3O4, the composite exhibited multiple loss mechanisms and excellent impedance matching. As a result, a minimum reflection loss of -56.24 dB was achieved at 11.63 GHz (2.9 mm thickness), with an ultra-wide effective absorption bandwidth of 8.1 GHz. More importantly, by integrating 3D printing with metamaterial-inspired design, the absorption range was successfully extended into the low-frequency region (4–6 GHz), while simultaneously enhancing structural integrity and corrosion resistance. This study offers a scalable strategy for designing lightweight, corrosion-resistant microwave absorbers by combining hierarchical conductive frameworks with multifunctional components, opening new avenues for next-generation EM shielding and stealth technologies.