Polyaniline-Functionalized Nanosized Cobalt Ferrite-Decorated\nMoS<sub>2</sub> Composites for Broadband Electromagnetic Wave Absorption

This study presents the synthesis\nof polyaniline (PANI)-coated\ncobalt ferrite-decorated molybdenum disulfide (MoS<sub>2</sub>@CoFe<sub>2</sub>O<sub>4</sub>); a composite architecture engineered to combine\nunique morphological, magnetic, and dielectric properties for the\nelectromagnetic wave/radar absorption applications. MoS<sub>2</sub> and CoFe<sub>2</sub>O<sub>4</sub> were produced separately using\na one-step hydrothermal process. Then, the CoFe<sub>2</sub>O<sub>4</sub> nanoparticles were integrated into the flower-like MoS<sub>2</sub> nanosheets using the sonication method. Finally, PANI was synthesized\nthrough in situ polymerization of aniline on the surface of MoS<sub>2</sub>@CoFe<sub>2</sub>O<sub>4</sub> to create the final design\nas well as to boost the dielectric performance. Structural analysis\nconfirmed the existence of the 2H phase and a minor trace of the 1T\nphase in MoS<sub>2</sub>, while CoFe<sub>2</sub>O<sub>4</sub> displayed\na cubic structure without any detectable impurities. Scanning electron\nmicroscopy verified the successful distribution of CoFe<sub>2</sub>O<sub>4</sub> particles within the MoS<sub>2</sub> nanosheets, aligning\nwith the design’s intended configuration. The electromagnetic\nwave (EMW) characteristics of the composites were analyzed by using\na vector network analyzer. The MoS<sub>2</sub>@CoFe<sub>2</sub>O<sub>4</sub> demonstrated a broad effective absorption bandwidth, spanning\nfrom the X-band to the Ku-band with a minimum matching thickness of\njust 2 mm. The reflection loss minimum value (<i>RL</i><sub>min</sub>) reached −22.82 dB at 8.96 GHz, corresponding to\na 99.47% absorption of the incident EMWs. The addition of PANI at\n50% by weight further increased the <i>RL</i><sub>min</sub> value to approximately 99.999% absorption (−50 dB), indicating\nenhanced impedance matching and absorption efficiency.