Synergistic enhancement of conductivity and magnetic loss in Co@C/Cu carbon foam toward absorption-dominated electromagnetic interference shielding

Abstract The escalating proliferation of electromagnetic (EM) radiation pollution necessitates the development of high-performance, lightweight, and EMI shielding materials with absorption-dominated shielding behavior. In this study, a hierarchically structured composite carbon foam (Co@C/Cu-CF) was successfully fabricated by integrating ZIF-67-derived Co@C hybrids and ultrafine spherical copper powder into a phenolic resin-based carbon foam scaffold via a facile slurry impregnation-carbonization route. The EMI shielding characteristics of the composite carbon foams with varying Co@C loadings was systematically investigated in the X-band. The 10wt% Co@C/Cu-CF composite achieved a superior total EMI shielding effectiveness (SE T ) of 34.2 dB at 8.2 GHz, with an absorption contribution exceeding 75%, signifying a distinct absorption-dominant shielding mechanism. This outstanding performance is primarily attributed to the synergistic effect of multiple loss pathways, including conductive loss derived from the continuous three-dimensional network, interfacial polarization and dipole polarization at numerous heterointerfaces, and magnetic loss originating from uniformly dispersed Co nanoparticles. Furthermore, the composite foam delivered a high specific EMI SE of 96.11 dBcm 2 g −1 , thereby demonstrating immense potential for next-generation lightweight and high-efficiency EMI shielding applications.