Constructing mixed-dimensional lightweight magnetic cobalt-based composites heterostructures: An effective strategy to achieve boosted microwave absorption and self-anticorrosion

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.