The advancement of cutting-edge technologies, including hypersonic vehicles, aerospace transportation platforms, and fusion energy systems, is driving the transition in electromagnetic stealth requirements from room-temperature conditions to extreme environments. However, traditional wave-absorbing materials suffer severe performance degradation at temperatures above 500 °C or under corrosive and irradiated conditions. Owing to their unique thermodynamic stability and tunable multi-element structures, high-entropy materials provide a promising route to address these challenges. This review systematically summarizes the electromagnetic-wave absorption behavior and structural evolution of high-entropy alloys, high-entropy ceramics, and high-entropy MAX/MXene materials under extreme conditions such as oxidation (550-1600 °C), salt-spray exposure, cryogenic temperatures, and thermal shock. Particular emphasis is placed on elucidating the mechanisms enabling efficient electromagnetic dissipation, including composition design, microstructural engineering, and multi-mode coupling. Reported studies indicate that these materials can achieve reflection losses below −30 dB and effective bandwidths exceeding 10 GHz across a variety of systems while maintaining excellent environmental stability. Future research opportunities include machine-learning-assisted multi-objective optimization, scalable fabrication strategies, and the development of sustainable high-entropy absorber systems for practical deployment in extreme environments.

With the growing prominence of electromagnetic pollution, the development of lightweight, flexible, and highly efficient electromagnetic wave (EMW) absorption materials has become an important research focus. Inspired by biological Turing structures, this study successfully prepares novel flexible ZrO₂/C nanofibers with a spotted reaction-diffusion pattern via a controlled oxidation strategy from preformed ZrC/C nanofibers. The ZrO₂/C nanofibers sample contains ZrO₂ particles embedded within a carbon matrix, which contributes to the formation of numerous heterogeneous interfaces. Furthermore, both the ZrO₂ and carbon matrix exhibit a mixed amorphous-nanocrystalline structure, thereby enhancing interfacial diversity and density. The ZrO₂/C Turing structural characteristic enhances impedance matching in the nanofibers and significantly improves the polarization loss capability. The obtained novel nanofibers achieve a minimum reflection loss of −59.20 dB, a maximum effective absorption bandwidth of 5.84 GHz, and require a matching thickness of only 2.39 mm. Computer simulation technology (CST) simulations indicate a maximum radar cross-section reduction of 34.94 dB m², highlighting the material’ s radar stealth capability. The study provides a new strategy for designing lightweight and high-performance fiber-based EMW absorption materials.