Tunable sulfur vacancies and hetero-interfaces of FeS₂-based composites for high-efficiency electromagnetic wave absorption

Controlling Vacancies and heterointerfaces of nano/microstuctures is very challenging, importantly, which tailors the electromagnetic (EM) parameters to develop the high-performance electromagnetic wave (EMW) absorbers. Herein, we report a strategy using various sulfur-source modifying Fe₃O₄ nanosphere by one-step hydrothermal method to prepare a series of FeS₂-based composites. Diverse sulfur sources determine their morphologies, crystal structures and compositions, and further affect EMW absorption abilities. Among these materials, rich sulfur vacancies and abundant heterogeneous interfaces improve their conduction loss and polarization loss caused by a unique concave cubic polyhedrons structure of the Fe₃O₄/FeS₂ composites fabricated by thioacetamide (TAA), which displays the brilliant EMW absorption capacity compared to others. That is, it possesses the minimum reflection loss (RL_min) of −59.27 dB and effective absorption bandwidth (EAB, RL ≤ -10 dB) of 5.86 GHz at the thin thickness of 1.8 mm. This study opens a new avenue for designing the superior EMW absorbers by tunable sulfur vacancy and heterointerface.