Regulating Local Coordination Environment of Single‐Atom Co Absorbers for Dielectric‐Magnetic Dual Loss Modulation

ABSTRACT Single‐atom materials with well‐defined microstructures offer unique opportunities for revealing electromagnetic energy dissipation mechanisms. However, research on the optimization of local electronic states to achieve dielectric–magnetic collaborative losses remains rare. Herein, a dipole–spin synergistic regulation was realized in cobalt single‐atom (Co‐SA) absorbers through atomic‐scale coordination engineering. Experimental and theoretical analyses revealed that asymmetric coordination facilitates enhanced dipole polarization, thereby improving dielectric loss, while the low‐spin to high‐spin transition increases the magnetic moment, resulting in strengthened magnetic loss. This dielectric–magnetic synergistic regulation constructs superior atomic‐level absorption centers, enabling outstanding electromagnetic wave absorption (EWA) with a minimum reflection loss of −54.87 dB and an effective absorption bandwidth of 5.36 GHz. This work demonstrates a scalable approach for the precise design and optimization of high‐performance EWA materials and offers a new insight into the relationships between the single‐atom coordination environment and the EWA performance.