Magnetic-dielectric synergy and interfacial engineering to design yolk–shell structured CoNi@void@C and CoNi@void@C@MoS2 nanocomposites with tunable and strong wideband microwave absorption

In order to effectively utilize the magnetic-dielectric synergy and interfacial engineering, in this paper, yolk—shell structured magnetic multicomponent nanocomposites (MCNCs) including CoNi@void@C and CoNi@void@C@MoS2 were produced in large scale by in-situ pyrolysis of cubic CoNi Prussian blue analogs (PBAs) followed by the hydrothermal process, respectively. Because of their unique structures, excellent synergistic effect between dielectric and magnetic loss, the as-prepared CoNi@void@C and CoNi@void@C@MoS2 MCNCs displayed very outstanding electromagnetic wave absorption performances (EMWAPs) including strong absorption capabilities, broad absorption bandwidth and thin matching thicknesses. Furthermore, the as-prepared CoNi@void@C and CoNi@void@C@MoS2 MCNCs well maintained the cubic configuration of CoNi PBAs even after the thermal treatment and hydrothermal processes. The unique structure and formed carbon layers effectively prevented the corrosion of internal CoNi alloy during the formation of MoS2, and CoNi@void@C@MoS2 MCNCs with different MoS2 contents could be synthesized by controlling the hydrothermal temperature. The obtained results revealed that the EM parameters, dielectric and magnetic loss capabilities of CoNi@void@C@MoS2 MCNCs could be tuned by controlling hydrothermal temperature and filler loading, which made their outstanding EMWAPs could be achieved in different frequency regions. Taking account of simple process, low density and high chemical stability, our findings provided a new and effective pathway to develop the strong wideband microwave absorbers.