Construction of Carbon Foam With Micro‐Meso‐Macropores and In‐Plane Multi‐Components for Microwave Absorption

ABSTRACT The unique advantages of porous materials with spatial arrangement have inspired the development of advanced microwave absorption (MA) materials. It is a good strategy to design pore sizes and a customized spatial arrangement for optimizing electromagnetic synergistic behaviors. Herein, a micro‐meso‐macropores structure with in‐plane multi‐components has been successfully constructed in carbon foam (CF). The innovative design is that the poly(3,4‐ethylenedioxythiophene)‐poly(styrenesulfonate) film on CF not only serves as an in situ source of O and S anions for forming Co, CoO, and Co 9 S 8 phases through ion‐exchange and competitive reactions, but also effectively induces an in‐plane arrangement of carbon nanocoils and metal‐organic frameworks (MOFs). Experiments and simulations revealed a multi‐level collaborative attenuation mechanism spanning from macroscopic conductive loss to nanoscale polarization. More importantly, the in‐plane configuration of multi‐components further amplifies electromagnetic coupling. The optimized structure achieved excellent broadband absorption performance across a wide range of incidence angles. Furthermore, after an additional periodic structural design, the effective absorption bandwidth was expanded from 8 to 12 GHz, and the minimum reflection loss value was improved from −20.5 to −60 dB. Analysis indicates that the ultra‐broadband characteristics of the array microwave absorber originate from the synergistic regulation of electromagnetic cooperative effects and edge diffraction effects by the periodic structure.