Yixuan Han, Yuren Yang, Tonghua Li, Yali Zhang*, Hua Guo, Mukun He, Kehua Han*, Hua Qiu, Junwei Gu*. Hierarchical Heterogeneous Co-based Magnetic Absorbers for Superior Broadband High-efficiency Microwave Absorption, Advanced Functional Materials, 2025, 10.1002/adfm.202525719. 2024IF=19.0.（1区材料科学Top期刊）

https://advanced.onlinelibrary.wiley.com/doi/10.1002/adfm.202525719

Abstract

Microwave absorbing materials are crucial for digital industries, communication networks, and stealth technology. However, precise microwave absorption performance control through microstructure design remains challenging. Herein, a strategy based on multiple equilibrium/competitive reactions is developed to fabricate Co-based microwave absorbers with tunable morphologies. The core–shell spherical cobalt (CS-SC) exhibits superior microwave absorption performance due to optimized impedance matching and interfacial effects. It achieves an effective absorption bandwidth (EAB) of 8.3 GHz (9.7–18.0 GHz) at 2.1 mm thickness, with a minimum reflection loss (RL_min) of -51.6 dB. Radar cross-section (RCS) simulations confirm a low RCS (＜-20.0 dB·m²) over incident angles from -90° and 90°. This work provides novel insights into the microstructural engineering of magnetic absorbers via solvothermal methods and the strategic modulation for their microwave absorption performance.

电磁波吸收材料在数字化产业、通讯网络和特种装备隐身等快速发展的领域中发挥着关键作用。然而，如何通过精细的微观结构设计实现电磁波吸收材料电磁波吸收性能的有效提升和精准调控，仍然面临诸多挑战。本文提出一种基于同一Co前驱体，通过多重平衡/竞争反应调控Co基磁性电磁波吸收剂的相组成、形貌及微观结构的方法，实现其宽频强电磁波吸收性能的可控调节。具体地，采用乙二醇溶剂热法制备了球状（SC）、核壳球状（CS-SC）、片状（FC）和核壳片状（CS-FC）Co基磁性电磁波吸收剂。其中，CS-SC因其磁芯-介电壳结构提高的阻抗匹配特性及独特的界面效应，具有强而宽的电磁波吸收性能。当CS-SC质量分数为25 wt%时，其复合材料在2.1 mm处有效吸波带宽（EAB）高达8.3 GHz（9.7 GHz～18.0 GHz），对应最小反射损耗值（RL_min）为-51.6 dB，优于SC（2.7 GHz，-19.2 dB）、FC（1.0 GHz，-19.9 dB）和CS-FC（4.9 GHz，-33.6 dB）。此外，模拟仿真结果表明，CS-SC对宽入射角度（-90^o到90^o）电磁波均有极小的雷达散射截面积（RCS）（＜-20.0 dB·m²），优于SC（-9.0 dB·m²）、FC（-8.3 dB·m²）和CS-FC（-6.8 dB·m²），具有最佳的实际应用价值。本工作为溶剂热法合成磁性电磁波吸收剂的微观结构设计制备与电磁波吸收特性调制提供了新的思路。