Abstract: Subtle microstructure design and an appropriate multicomponent strategy are essential for advanced electromagnetic absorbing (EMA) materials with a wide effective absorption bandwidth (EAB) and intense absorption. However, sophisticated environments restrict the range of applications for EMA materials. Herein, three hollow spherical bifunctional CoS_x/MnS/C nanocomposites with different crystal structures were constructed via cation exchange and subsequent vulcanization. The manganese sulfide and carbon generated during vulcanization exhibit a narrow band gap and enhanced conductivity, thereby facilitating conductive loss. The presence of cobalt sulfide facilitates the improvement of magnetic loss. More importantly, there is a potential difference between different phases at the heterogeneous interface, resulting in a region of space charge, which is conducive to interfacial polarization. The 3D hollow structure and heterogeneous dielectric/magnetic interfaces benefit the predominant EMA performance by forming perfect impedance matching, interface polarization, conduction loss, and magnetic loss effects. Specifically, an optimal reflection loss (RL) of -51.31 dB at 10.72 GHz and an effective EAB of 5.92 GHz at 2.1 mm can be achieved for Co_1-xS/MnS/C nanocomposite. Moreover, the nanocomposites maintained promising self-anticorrosion properties in simulated seawater environments. Transition metal sulfides with superior self-anticorrosion properties provide a pathway to efficient wave-absorbing materials in complicated environments.

Key words: Heterogeneous interfaces, Dielectric/magnetic loss, Different crystal structure, Microwave absorption, Self-anticorrosion