Tailoring electromagnetic dissipation in high-entropy perovskites oxides through coupled defect engineering and valence-state modulation

The rapid advancement of wireless communication and electronic devices has significantly heightened the demand for high-performance electromagnetic (EM) wave absorbers to effectively mitigate EM interference and pollution. Although perovskite oxides (ABO 3 ) offer structural tunability that facilitates optimized impedance matching and enhanced polarization losses, achieving a balance between attenuation capacity and impedance matching remains a persistent challenge. Here, we present a high-entropy perovskite oxides (HEPOs) design strategy that overcomes these limitations through synergistic effects arising from multi-component integration. Using a facile sol-gel method, we synthesized (La 0.2 Ba 0.2 Sr 0.2 Ca 0.2 Na 0.2 )FeO 3-δ HEPOs with tailored multivalent Fe doping at the B-site, which induces gradient defect energy levels and significant lattice distortions. This approach enables the formation of a multi-scale polarization network, thereby prolonging EM wave propagation paths and enhancing dielectric/magnetic losses. Supported by crystal field theory analysis, we elucidate the dynamic evolution of iron valence states, orbital splitting mechanisms, and electron transfer kinetics in the Fe-O-Fe octahedral field. The resulting HEPOs exhibit outstanding reflection loss (RL) of −52.35 dB and an effective absorption bandwidth (EAB) of 5.12 GHz at a thickness of 1.7 mm, attributed to the synergistic contributions of interface polarization, dipole relaxation, and defect polarization. Importantly, the high-entropy effects imparts superior structural durability under harsh conditions, addressing a critical drawback of conventional absorbers. This study not only provides fundamental insights into high-entropy-driven EM regulation but also establishes a promising pathway for designing high-performance, thermally stable absorbers for next-generation EM mitigation applications. A novel A-site high-entropy perovskite oxide via sol-gel is synthesized, where defect engineering and valence modulation induce strong polarization and magnetic resonance. This material delivers remarkable microwave absorption performance and structural stability, providing a new design paradigm for high-performance electromagnetic absorbers.