With the widespread application of electronic devices, multifunctional electromagnetic wave (EMW) absorbing materials suitable for complex high-temperature and high-pressure environments, have attracted tremendous research attention. Herein, multifunctional polyimide (PI) composites doped with fluffy NbO/CNTs microspheres (NBCP) were prepared by combining the ultrasonic spraying process and freeze-drying technique. Introduction of fillers results in the formation of diverse conduction paths and heterogeneous interfaces, which enhance the dielectric loss. Furthermore, the multi-porous structure of the PI matrix induces multiple reflection scattering events and improves the impedance matching. Such a multi-loss mechanism endows NBCP with an excellent EMW absorption performance. At 15 vol% filling, the minimum reflection loss is −41.66 dB, the effective absorption bandwidth is 2.63 GHz, and the radar cross-section is reduced by 85%. Furthermore, NBCP exhibits outstanding mechanical properties and a thermal insulation of over 100 °C in thermal environment at 150 °C. The proposed multifunctional NBCP is thus an efficient EMW absorber that offers significant potential for applications in harsh environments.

中文翻译：

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轻质Nb2O5/CNTs/聚酰亚胺的高效电磁波吸收，具有优异的隔热性和抗压集成性

随着电子设备的广泛应用，适用于复杂高温高压环境的多功能电磁波吸波材料引起了人们的广泛研究关注。本文采用超声波喷涂工艺与冷冻干燥技术相结合的方法制备了掺杂蓬松NbO/CNTs微球（NBCP）的多功能聚酰亚胺（PI）复合材料。填料的引入导致形成不同的传导路径和异质界面，从而增加介电损耗。此外，PI矩阵的多孔结构引起多次反射散射事件并改善阻抗匹配。这种多重损耗机制赋予了NBCP优异的电磁波吸收性能。填充量为15 vol%时，最小反射损耗为-41.66 dB，有效吸收带宽为2.63 GHz，雷达截面积减小85%。此外，NBCP还表现出优异的机械性能，在150℃的热环境中隔热性能可达100℃以上。因此，所提出的多功能 NBCP 是一种高效的 EMW 吸收器，为恶劣环境中的应用提供了巨大的潜力。