Flower-like Cu9S5 and magnetic NiCo@C particles synergize to build three-dimensional conductive networks for efficient electromagnetic wave absorption

Abstract

To increase the use of sulfides in electromagnetic wave absorption, researchers are continuously developing thin semiconductor sulfide absorbers with significant absorption capacity and wide bandwidth. In this study, we synthesized NiCo@C/Cu 9 S 5 materials with the dual loss mechanism (dielectric and magnetic losses) by evenly loading magnetic NiCo@C particles on flower-like Cu 9 S 5 matrixes utilizing the magnetic derivatization technique for metal-organic frameworks (MOFs). The three-dimensional flower-like structures of the composites, intrinsic properties of the materials, and the resulting three-dimensional conductive network endow the material with multiple scattering and reflection, conduction loss, resonance, and eddy current properties. The synergistic effect of these loss pathways leads to the outstanding electromagnetic wave (EMW) absorption performance of the materials. The results show that the minimum reflection loss (RL min ) of NiCo@C/Cu 9 S 5 can reach −52.83 dB when the matching thickness is 2.09 mm. Meanwhile, the maximum effective absorption band (EAB) is 5.1 GHz (12.3–17.4 GHz) at a matching thickness of 1.69 mm. Furthermore, the radar cross section (RCS) of the absorbers has been calculated by CST Studio Suite, demonstrating the ability of the absorbent coating to lower the RCS at different angles efficiently. These discoveries provide new insights for high-performance sulfide electromagnetic wave absorbers and contribute to electromagnetic wave energy storage and conversion studies. • Flower-like NiCo@C/Cu 9 S 5 were obtained by magnetic derivatization technique for MOFs. • The presence of heterogeneous interfaces and defect sites promotes interfacial polarization and dipole polarization of the composites. • The formation of three-dimensional conductive networks enhance electron migration. • The RL min of NiCo@C/Cu 9 S 5 is −52.83 dB and the EAB max is 5.1 GHz.