Sodium citrate-induced generation of multi-interfacial embroidered spherical SnO2 for augmented electromagnetic wave absorption

Abstract

Research into electromagnetic radiation enhancement and frequency band broadening is growing in popularity with the advance of 5G connected communication technology. As such, there is an urgent need for wave-absorbing materials that meet both the broadband and strong absorption requirements. Dielectric materials, as a class of lightweight materials with controllable morphology, are one of the many candidates, but their inherent properties make it tough to simultaneously match impedance and strong attenuation, so they cannot meet both broadband and strong absorption requirements. Here, we compensate for the intrinsic properties of dielectric materials by means of shape modulation, which can achieve a win–win situation of impedance and attenuation. When the response time is 8 h, the material studied achieves robust absorption (reflection loss value reaches −45.6 dB) and a wide frequency band (6.08 GHz) at 2.6 mm. Given that the material has a multi-vacancy embroidered spherical structure, it allows multiple reflections of electromagnetic waves and improves the conductive loss. Also, the nanosheet cross-stacking builds multiple interfaces, and the resulting interfacial polarization becomes the most important part of the dielectric loss. Meanwhile, it can be further demonstrated by simulation and radar scattering area solution that the interfacial polarization constructed from the embroidery spherical structure leads to exceptional wave absorption performance. This work suggests a concept for the preparation of practical absorbing materials with strong absorption, a wide frequency band and multiple interfaces.