Modulating polarization and conduction loss for optimized electromagnetic wave absorption performance of FeNi/ZnO/C/Ni3ZnC0.7 composites

Polarization loss and conduction loss are the important attenuation mechanisms in dielectric loss dominant electromagnetic wave (EMW) absorbers, but their synergistic effects in different frequency bands need to be further investigated. In this study, FeNi/ZnO/C/Ni3ZnC0.7 composites (FNZC) were synthesized using a simple and environmentally friendly template-sacrificing method, with water as the only solvent. By varying the elemental addition, the phase and microstructure of the final product can be controlled, which in turn affects the conduction loss and polarization loss, thus altering the EMW absorption performance. The minimum reflection loss (RL) value and EAB of the optimized FNZC composite are -49.23 dB and 5.48 GHz (12.32-18.00 GHz), respectively, covering 99.9 % of the Ku band. Additionally, the RLmin values in the S, C, and X bands are below -17 dB. Based on the component regulation strategy and the analysis of electromagnetic parameters, Cole-Cole curves, and EMW absorption performance, it can be concluded that conduction loss is the primary factor contributing to strong absorption of low-frequency EMW. In contrast, interfacial polarization and defect-induced polarization are the main factors for strong absorption of medium- and high-frequency EMW.