Nanoscale Dielectric Gene Dual-Regulations in High-Entropy Materials for Enhanced Electromagnetic Wave Absorption...

The demand for low-mid frequency electromagnetic wave absorption (EWA) materials over 5G commercial bands is urgently increasing recently. However, the unpredictable parameter fluctuations in low-mid frequency EWA performance make it difficult to realize effective microstructure/microcomponent designing. To this end, a feasible strategy is proposed to reasonably optimize the nanoscale dielectric characteristics in high-entropy materials (HEM). The synergistic grain refinement and lattice distortion enable us to precisely match electromagnetic parameters, therefore enhancing dielectric loss that covers the low-mid frequency absorption band. In detail, Mn-doped carbon-coated high-entropy alloy nanoparticles (Mn-HEA@C) allow for enhanced grain refinement, increased grain boundaries and phase interfaces, thereby triggering improved interface polarization and conductive loss. Meanwhile, the increased lattice distortion introduces defect-induced dipoles that contribute to enhanced relaxation losses. Collectively, Mn₁-HEA@C realizes efficient coverage of 5G low-frequency communication bands (N77/78/79) with an effective absorption bandwidth (EAB) of 4.76 GHz, noticeably showing strong absorptions of -50.7 dB at 11.71 GHz and -43.4 dB at 4.91 GHz, respectively. These new findings suggest the nanoscale dielectric gene dual-regulation strategy greatly contributes to optimized impedance matching and electromagnetic attenuation and lay solid foundations for novel absorbers that emphasize on low-mid frequency absorption.