The Elaborate Design of Multi‐Polarization Effect by Non‐Edge Defect Strategy for Ultra‐Broad Microwave Absorption

• Published in: Advanced functional materials 2024-10, Vol.34 (44), p.n/a
• Main Authors: Fang, Gang, Liu, Chuyang, Xu, Meng, Zhang, Xiaohan, Wu, Yue, Kim, Dong‐Hyun, Ji, Guangbin
• Format: Article
• Language: English
• Subjects: Activated carbon; Anions; Bandwidths; broad absorption bandwidth; Broadband; Carbon; Cementite; Composite materials; Configuration management; Customization; Defects; Frequency ranges; Iron carbides; magnetoelectric composites; Microwave absorption; multi‐polarization effect; non‐edge doping; Polarization
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202404532

Anion defect engineering is proven to be an efficient approach to reconstruct the electronic configuration of carbon‐based magnetoelectric materials for targeted modulation of electromagnetic (EM) performance. However, traditional mono‐anionic doping suffers from low defect concentration and lacks diverse polarization mechanisms. In this work, multi‐anions (N/S/F) stepwise‐doped carbon/Fe3C magnetoelectric composites are elaborately constructed, wherein the predesigned N defects serve as activated sites for anomalously adopting S anions (Step I) and subsequent F anions (Step II) in non‐marginal areas of the carbon layer. It is found that S prefers to replace pyrrolic N defects while F tends to form dangling bonds with the C site adjacent to the pyridinic N. Intriguingly, besides the inherent polarized resonance of N defect at ≈15 GHz, customized S and F defects induce new polarization resonances at ≈10 GHz and ≈15+ GHz, respectively. Under a typical multi‐polarization effect with the synergetic magnetic response, the carbon/Fe3C composites with N/S/F defects harvest the broadest bandwidth of 8.28 GHz (9.72–18 GHz) at 2.55 mm, covering a wide frequency range almost from X to Ku bands. This work demonstrates the positive impact of localized multi‐defects customization and multi‐polarization effect on expanding microwave absorption bandwidth, providing valuable insights for the advanced design of ultra‐broadband absorbers. This work constructs the multi‐anions (N/S/F) non‐edge doped carbon/Fe3C magnetoelectric composites are elaborately to develop synergetic multi‐polarization effect covering the frequency range of 9–18 GHz, realizing the broadest bandwidth of 8.28 GHz at 2.55 mm. Therefore, this study offers reliable reference value for developing carbon‐based ultra‐broadband absorbers by localized multi‐defects customization and multi‐polarization effect.