Harnessing local chemical order in high-entropy ceramics for broadband electromagnetic absorption

Electromagnetic pollution from the rapid expansion of wireless and electronic systems demands advanced absorber materials. High-entropy ceramics offer a promising platform for broadband electromagnetic wave attenuation, yet their rational design remains underdeveloped. Here, we introduce a mechanism-driven strategy to enhance absorption by tailoring local chemical order via simple thermal processing. Applied to high-entropy carbides, this local chemical order-engineering approach delivers a record effective absorption bandwidth of 11.2 GHz. Atomic-resolution chemical mapping paired with theoretical simulations reveals that local chemical order, rather than atomic vacancies, governs the dominant electromagnetic wave absorption mechanisms. We further demonstrate the universality of this principle across diverse high-entropy ceramic families (borides, oxides, sulfides, silicides, and selenides), each exhibiting substantial performance gains. This work establishes a clear, structure-guided framework for designing high-performance single-phase absorbers and offers a versatile route to mitigate electromagnetic pollution through targeted control of atomic-scale chemical order.