The innovative microstructure design and suitable multicomponent strategy are still challenging for advanced electromagnetic absorbing materials (EAMs) with strong absorption and wide effective absorption bandwidth (EAB). Here, the self-assembly 3D mesh structure of NiCo2(CO3)3/RGO (NCR) aerogels was prepared by a simple hydrothermal reduction. The unique microstructure and multicomponent not only solve the physical agglomeration of NiCo2(CO3)3 particles but also adjust the electromagnetic parameters to improve impedance matching and attenuation ability. The high electromagnetic wave absorption (EMA) performance can be achieved by the synergistic effect of the interfacial matrix and macroscopic 3D interconnected mesh structures, the minimal reflection loss (RLmin) was -58.5 dB at 2.3 mm, and the EAB was 6.5 GHz. The excellent EMA performance of NiCo2 (CO3)3/RGO aerogels can be attributed to the multiple reflection, scattering, and relaxation process of 3D porous structure and strong interface polarization of the interfacial matrix.The data set includes synthesis steps, XRD, XPS, SEM, composite permittivity, composite permeability, minimum reflection loss, impedance matching and mechanism summary.