Multiphase High-Entropy Carbon Sphere: Defect Engineering and Multispectral Electromagnetic Response

Due to the excellent multifunctional compatibility of high-entropy materials (HEM), the multispectral electromagnetic (EM) response of HEM and their potential multifunctional applications have received extensive attention. Herein, a “rare-earth fixation + high-voltage dispersion” strategy is developed to prepare carbon fiber self-assembled carbon spheres (CS) simultaneously loaded with carbon-defects and multiphase high-entropy particles featuring high-concentration oxygen vacancies (Ov) via flash Joule-heating within 50 ms. The phase composition can be tuned by modulating the content of rare-earth, thereby widely adjusting the imaginary part of permittivity ɛ″ (ɛ″_max: 7.97-42.36), and ultimately obtaining a wide effective absorption bandwidth close to 7.0 GHz (frequency band with reflection loss < −10 dB) leveraging the synergistic effects of multiphase interfaces, Ov and carbon defects. Additionally, the Ov-rich high-entropy alloys/high-entropy oxides interface imparts sunlight responsiveness to HEM, and under the condition of “1-sun”, the increase in photocurrent can reach 0.326 µA cm⁻². With the excellent corrosion resistance of high-entropy CS, this study offers novel insights into the integrated design and control of multispectral EM-responsive materials, significantly promoting the development of multifunctional EM devices suitable for harsh corrosive environments.