Rigid interface induced structural transformation in Zn, Ni-ZIF for enhanced electromagnetic wave attenuation

The modulation of zeolitic imidazolate framework (ZIF) −derived carbon materials predominantly rely on adjusting the types of inorganic metal and organic ligands, as well as optimizing the morphology and topological structure. However, the existing preparation methods limited the mechanistic investigation of micro-morphology structure on electromagnetic waves absorption properties. Hence, utilizing the unique d₈ electron configuration of Ni²⁺ and rigid-interface-induced outward contraction mechanism, we designed hollow-like, flower-like, yolk-shell-like Zn, Ni-doped ZIF-derived carbon materials by modifying the thickness of the rigid interface. For the reason that the abundance of pores and multiple heterogeneous interfaces are beneficial for dipole and interface polarization, the flower-like Zn, Ni-doped ZIF-derived carbon materials with multiple resonant cavities achieved a prominent electromagnetic wave absorption performance, showing a minimum reflection loss of −57.69 dB at 2.5 mm and an effective absorption bandwidth of 5.52 GHz at 2.1 mm thickness. The radar cross-section (RCS) simulation can express the absorption efficiency of wave-absorbing agents, we found that sample possesses the lowest RCS signals. The improved microwave absorption can be attributed to the dielectric loss from the dipole and interface polarization. This work demonstrates that different morphologies can be induced by regulating the contraction mechanism of ZIF and explores the influence of morphology on the absorption mechanism.