Constructing multi-layer heterogeneous interfaces in liquid metal graphite hybrid powder: Towards microwave absorption enhancement

• Published in: Journal of colloid and interface science Vol. 677; no. Pt A; pp. 79 - 89
• Main Authors: Zhao, Kun-Yan, Sun, Chang, Huang, Ming-Lu, Luo, Cheng-Long, Wang, Ming
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.01.2025
• Subjects: absorption; electrical conductivity; gallium; graphene; Graphite powder; Heterojunction interface; Liquid metal; liquids; Microwave absorption; powders; surface area; Liquid metal; Graphite powder; Heterojunction interface; Microwave absorption
• ISSN: 0021-9797; 1095-7103; 1095-7103
• DOI: 10.1016/j.jcis.2024.07.189

[Display omitted] •Gallium coated graphite hybrid particles were prepared.•The hybrid particles have excellent microwave absorption performance.•The formation of gallium oxide shell is very important to microwave absorption.•Heterogeneous interfaces are constructed in the hybrid particles.•Dipole and interfacial polarization is enhanced by these heterogeneous interfaces. Carbon based materials are widely used in the preparation of microwave absorption materials due to their low density, high attenuation loss and large specific surface area. However, their high conductivity usually leads to high reflection loss. In this study, multi-layer heterogeneous interfaces were constructed in liquid metal graphite hybrid powder to reduce reflection loss and enhance microwave absorption performance. Gallium oxide (Ga2O3) layer was formed in Ga coated graphite powder to improve impedance matching and attenuation constant via an annealing treatment. Specifically, the hybrid particles with 50 wt% Ga and being annealed at 120 °C for 2 h have a minimum reflection loss (RLmin) value of −42.68 dB and a maximum effective absorption bandwidth (EAB) of 4.11 GHz at a thickness of 3.3 mm. The hybrid particles not only have multi-layer structures with different electrical conductivity, but also form heterojunctions between different interfaces, which can further enhance dipole and interfacial polarization.