Rapid Microwave Plasma Engineering of HfO 2 /C@C Core‐Shell Fibrous Membrane Toward Flexible High‐Performance Electromagnetic Wave Absorption
Qichao Ding, Limeng Song, Wei Li, Jiangtao Hao, Xuewen Jiang, Mengru Li, Xinglai Yuan, Gang Wang, Yanqiu Zhu, Mi Tian, Hailong Wang, Hongxia Li, Biao Zhao, Rui Zhang, Bingbing FanABSTRACT
Flexible electromagnetic wave (EMW) absorbers that simultaneously exhibit excellent impedance matching, strong attenuation capability, and mechanical robustness remain highly desirable yet challenging to realize, particularly for dielectric HfO 2 ‐based materials owing to their intrinsically low conductivity and limited polarization capability. Herein, a rapid and environmentally friendly CO 2 microwave plasma torch strategy is developed to fabricate flexible HfO 2 /C@C core‐shell fibrous membranes with tunable defects. The ultrafast plasma process simultaneously regulates the crystalline structure of HfO 2 , the graphitization of the carbon shell, and the concentration of oxygen vacancies, thereby constructing highly coupled dielectric‐conductive heterointerfaces. Therefore, the optimized HfO 2 /C@C‐2 sample exhibits outstanding microwave absorption, with a minimum reflection loss of −65.75 dB at 3.2 mm and an effective absorption bandwidth of 7.37 GHz. Meanwhile, the interconnected one‐dimensional fibrous network endows the material with excellent flexibility and fatigue resistance, while radar cross‐section simulations further demonstrate its superior stealth capability. This work establishes a clear processing‐structure‐property relationship and proposes a green plasma strategy to overcome the performance‐practicality trade‐off of HfO 2 ‐based absorbers, providing a promising route toward next‐generation flexible EMW absorbing materials.