Construction of self-assembled bilayer core-shell V2O3 microspheres as absorber with superior microwave absorption performance

The design and preparation of heterogeneous structures of dielectric materials has been the main-stream direction for the construction of superior microwave absorption materials (MAMs). We report a facile and efficient procedure combination of hydrothermal process and subsequent heat treatment for successfully prepared bilayer core-shell structure self-assembled V2O3 microspheres (BCSV). The microstructure, defects, dielectric properties and microwave absorption (MA) properties of BCSV were systematically investigated, and the effect of bilayer core-shell structure on the MA properties was dis-cussed. By varying the heat treatment temperature, it is feasible to regulate the thickness of V2O3 bilayer and its unique structure defects, hence enhancing the attenuation and multiple polarization loss of electromagnetic waves inside the microspheres. Self-assembled V2O3 microspheres with bilayer core-shell structure exhibit high-performance MA property. The reflection loss (RL) gets to -67.12 d B at 11.69 GHz covering the whole X-band after heat treatment at 600 degrees C, and the broad effective absorption bandwidth is 5.49 GHz with a thickness of 2.20 mm. The conductivity loss, multiple polar-ization loss and dielectric loss are ascribed to the specific bilayer core-shell structure. Thus, our work provides a good perspective on how to create vanadium oxide-based MAMs with effective absorption and broad bandwidth.(c) 2023 Elsevier Inc. All rights reserved.

Automated summary

In this study, a bilayer core-shell structure self-assembled V2O3 microspheres (BCSV) was successfully prepared through a combination of hydrothermal process and subsequent heat treatment. The microstructure, defects, dielectric properties, and microwave absorption (MA) properties of BCSV were investigated, and the effect of bilayer core-shell structure on the MA properties was discussed. By adjusting the heat treatment temperature, the thickness of the V2O3 bilayer and its unique structure defects can be regulated, thereby enhancing the attenuation and multiple polarization loss of electromagnetic waves inside the microspheres. BCSV exhibits a high-performance MA property, with a reflection loss (RL) of -67.12 dB at 11.69 GHz and a broad effective absorption bandwidth of 5.49 GHz with a thickness of 2.20 mm after heat treatment at 600 degrees C. The conductivity loss, multiple polarization loss, and dielectric loss are attributed to the specific bilayer core-shell structure. Thus, this work provides a good perspective on how to create vanadium oxide-based MAMs with effective absorption and broad bandwidth.