Laboratory of Advanced Materials, Shanghai Key Lab of Molecular Catalysis and Innovative Materials, Academy for Engineering & Technology, Fudan University, Shanghai, 200438, P. R. China.
School of Microelectronics, Fudan University, Shanghai, 200433, P. R. China.
Small. 2023 Jun;19(25):e2300363. doi: 10.1002/smll.202300363. Epub 2023 Mar 17.
Although assembled hollow architectures have received considerable attention as lightweight functional materials, their uncontrollable self-aggregation and tedious synthetic methods hinder precise construction and modulation. Therefore, this study proposes a bi-ion synergistic regulation strategy to design assembled hollow-shaped cobalt spinel oxide microspheres. Dominated by the coordination-etching effects of F and the hydrolysis-complex contributions of NH , the unique construction is formed attributed to the dynamic cycles between metal complexes and precipitates. Meanwhile, their basic structures are perfectly retained after reduction treatment, enabling FeCo/CoFe O bimagnetic system to be obtained. Subsequently, in-depth analyses are conducted. Investigations reveal that multiscale magnetic coupling networks and enriched air-material heterointerfaces contribute to the remarkable magnetic-dielectric behavior, supported by the advanced off-axis electron holography technique. Consequently, the obtained FeCo/CoFe O composites exhibit excellent microwave absorption performances with minimal reflection losses (RL ) as high as -51.6 dB, an effective absorption bandwidth (EAB) of 4.7 GHz, and a matched thickness of 1.4 mm. Thus, this work provides an informative guide for rationally assembling building blocks into hollow architectures as advanced microwave absorbers through bi-ion and even multi-ion synergistic engineering mechanisms.
虽然组装的空心结构作为轻质功能材料已经引起了相当大的关注，但它们不可控的自组装和繁琐的合成方法阻碍了精确的构建和调节。因此，本研究提出了一种双离子协同调控策略，用于设计组装的空心钴尖晶石氧化物微球。以 F 的配位蚀刻效应和 NH 的水解-络合贡献为主导，独特的结构是由于金属配合物和沉淀物之间的动态循环形成的。同时，它们的基本结构在还原处理后得到了完美的保留，从而获得了 FeCo/CoFe O 双磁系统。随后，进行了深入的分析。研究表明，多尺度磁耦合网络和丰富的气-固界面异质结构有助于显著的磁-电行为，这得益于先进的离轴电子全息技术。因此，所获得的 FeCo/CoFe O 复合材料表现出优异的微波吸收性能，最小反射损耗（RL ）高达-51.6 dB，有效吸收带宽（EAB）为 4.7 GHz，匹配厚度为 1.4 mm。因此，这项工作为通过双离子甚至多离子协同工程机制，将构建块合理组装成空心结构作为先进的微波吸收体提供了有价值的指导。
