Alkali and ion exchange co-modulation strategies to design magnetic–dielectric synergistic nano-absorbers for tailoring microwave absorption

Alkali and Co2+ co-modulation has seldom been investigated as a prospective strategy to achieve high-efficient microwave absorbing (MA) materials. In this work, a new alkali and Co ion exchange co-modulation strategy was first reported, leading to broadband MA capacity through simultaneous manipulating multiple factors, such as composition, micromorphology, and heterogeneous interface. And enhancements in impedance matching and magnetic-dielectric loss were synergistically realized. Consequently, the optimized FeCo alloy@porous carbon (FPC) nanocomposite with the alkali regulation delivered an effective absorption bandwidth (EAB) of 6.72 GHz, making it the merely single FeCo-based metal-organic framework derived FPC absorber with a low filler content of 15 wt.%. Interestingly, the nanocomposites by ion exchange strategy realized the switchable "on/off" states on electromagnetic response. Furthermore, the radar cross-section (RCS) reduction value of the products reached 25.6 dB center dot m(2) under the incident angle of 0 degrees. In brief, this work not only offers the special role of alkali and Co2+ co-modulation in composition regulation, structure design, and MA capacity, but also provides a reliable strategy to develop smart nano-absorbers to cope with electromagnetic pollution issues.