Wang Baolei, Wu Qian, Fu Yonggang, Liu Tong
Key Laboratory of Aerospace Materials and Performance (Ministry of Education), School of Materials Science and Engineering, Beihang University, No. 37 Xueyuan Road, Beijing 100191, PR China.
Key Laboratory of Aerospace Materials and Performance (Ministry of Education), School of Materials Science and Engineering, Beihang University, No. 37 Xueyuan Road, Beijing 100191, PR China.
J Colloid Interface Sci. 2021 Jul 15;594:342-351. doi: 10.1016/j.jcis.2021.03.011. Epub 2021 Mar 15.
Nowadays, high-performance microwave absorption materials with light weight, strong absorbing intensity and wide absorption bandwidth are urgently demanded to solve the electromagnetic pollution issues. In this work, the yolk-shell structured Co@SiO@Void@C nanocomposites with tunable cavity are obtained by etching SiO in the Co@SiO@C nanoparticles. They exhibit better microwave absorption properties than the unetched counterpart. When the etching time is 6 h, the Co@SiO@Void@C nanocomposite shows high absorption efficiency with a minimum reflection loss (RL) value of -44.5 dB at 8.8 GHz. Notably, its effective absorption bandwidth (RL < -10 dB) is as wide as 8.0 GHz (9.7-17.7 GHz) at a thin thickness of only 1.7 mm. The excellent microwave absorbing performances are attributed to the abundant heterointerfaces, well-controlled cavity, synergistic effects between magnetic and dielectric loss, and optimal impedance matching. Owing to the characteristics of strong absorbing capacity, ultrabroad absorption bandwidth and thin matching thickness, the yolk-shell structured Co@SiO@Void@C nanocomposites are promising candidates as highly effective microwave absorbers.
如今，迫切需要具有轻质、强吸收强度和宽吸收带宽的高性能微波吸收材料来解决电磁污染问题。在这项工作中，通过蚀刻Co@SiO@C纳米颗粒中的SiO获得了具有可调谐空腔的蛋黄壳结构Co@SiO@Void@C纳米复合材料。它们表现出比未蚀刻的对应物更好的微波吸收性能。当蚀刻时间为6小时时，Co@SiO@Void@C纳米复合材料显示出高吸收效率，在8.8 GHz处的最小反射损耗（RL）值为-44.5 dB。值得注意的是，在仅1.7 mm的薄厚度下，其有效吸收带宽（RL < -10 dB）宽达8.0 GHz（9.7 - 17.7 GHz）。优异的微波吸收性能归因于丰富的异质界面、良好控制的空腔、磁损耗和介电损耗之间的协同效应以及最佳的阻抗匹配。由于具有强吸收能力、超宽吸收带宽和薄匹配厚度的特点，蛋黄壳结构的Co@SiO@Void@C纳米复合材料有望成为高效微波吸收剂的候选材料。
