Hierarchical design of BaTiO₃@MnO₂/MWCNTs nanocomposites with enhanced microwave absorption and dielectric tunability via two-step hydrothermal synthesis

Compared to traditional magnetic wave-absorbing materials, paramagnetic electromagnetic wave-absorbing materials have garnered significant attention in microwave absorption due to their advantages, including low density, wide bandwidth, and thin structure. The polarization mechanism and dielectric loss are key factors determining the electromagnetic absorption performance of these materials. In this study, BaTiO₃@MnO₂/MWCNTs (BTMC) hybrid composites were prepared using a two-step solvothermal method, and the electromagnetic absorption performance was optimized by adjusting the MWCNTs loading in the absorber and the absorber-to-paraffin ratio. The synergistic effect of BaTiO₃'s excellent dielectric properties, the anisotropy of MnO₂ with different morphologies (urchin-like α-MnO₂ nanosheets and rod-like β-MnO₂), and the high conductivity of MWCNTs enhanced the electromagnetic absorption capacity of the BTMC hybrid composite. The study showed that when the paraffin wax-to-absorber ratio was 7:3 and the MWCNT loading in the absorber was 10 wt%, the composite material (BTMC-10) achieved a reflection loss (RL min ) of −74.06 dB and an effective absorption bandwidth of 1.27 GHz at a thickness of 4.75 mm. This provides a new research direction for developing high-performance, lightweight, broadband, and efficient paramagnetic electromagnetic wave-absorbing materials, demonstrating their potential applications in the microwave field.