Three-Dimensional Flower Multiphase Interface Cu3BiS3/CuS/Bi2S3 for Efficient Electromagnetic Wave Absorption

Metal sulfide composites present an opportunity to construct efficient electromagnetic wave (EMW) absorbing materials, owing to their tunable structure and excellent dielectric properties. This research presents the successful preparation of Cu 3 BiS 3 /CuS/Bi 2 S 3 (CSB) composites with a three-dimensional flower-like structure using a two-step microwave method. CuS with high conductivity was added to the Bi 2 S 3 -based composite material to optimize impedance matching and regulate conductivity. The generation of the Cu 3 BiS 3 intermediate phase facilitates superior interfacial polarization properties within the CSB composites. The results show that the resulting CSB2 composites had an optimum reflection loss of −66 dB at 11 GHz with a thickness of 2.19 mm. Additionally, they demonstrate an optimal effective absorption bandwidth of 3.9 GHz (14.1–18 GHz) with a thickness of 1.5 mm. The three-dimensional, flower-like structure of CSB composites facilitated multiple resonant cavity reflections of incident EMW, while the abundant heterogeneous interfaces promoted interfacial polarization capability, resulting in effective absorption and loss of EMW in CSB composites. This research aims to serve as a significant reference for the application of metal-based sulfides in the field of EMW absorption.