S-defect-rich CuS self-assembly with enhanced localized polarization for low-frequency electromagnetic wave absorption performance

The rapid expansion of military and civilian wireless technologies has exacerbated electromagnetic interference, creating a pressing need for high-performance low-frequency electromagnetic-wave absorbers (EWAs). Herein, we reported a self-assembled CuS (SA-CuS) architecture prepared via a dissolution-recrystallization mechanism. The high density of sulfur vacancies enhanced local polarization, which effectively modulated the dielectric constant and boosted the dielectric-loss capability. These synergistic effects significantly strengthened the material’s electromagnetic response in the low-frequency range. The composite exhibited a minimum reflection loss of -66.9 dB, and across the C-band (4-8 GHz) it offered an effective absorption bandwidth (RL ≤ -10 dB) that covered 42.5% of the entire C-band while maintaining an impedance-matching area ratio of 18.22%. This work demonstrated that rational microstructural engineering could precisely tailor electromagnetic properties, providing design principles and an experimental basis for next-generation low-frequency EWAs in electromagnetic compatibility, stealth, and 5G communication systems.