Implanting NiCo2O4 equalizer with designable nanostructures in agaric aerogel-derived composites for efficient multiband electromagnetic wave absorption

Abstract

A rational structural design is key to optimizing impedance matching and further enhancing the absorption performance. In this work, NiCo2O4@agaric aerogel-derived carbon hybrids (C@NCO), in which agaric aerogel-derived carbon served as a structural basis and NiCo2O4 with designable nanostructures acted as an equalizer to coordinate impedance matching and attenuation capacity, were successfully fabricated and the microstructure and microwave absorption properties were investigated in details. Benefiting from the multi-component integration and well-designed structures, the microwave absorption properties of dandelion-like C@NCO have been efficiently optimized: the minimum reflection loss is −54.6 dB at 4.09 mm and the effective absorption bandwidth covers 5.7 GHz at 1.85 mm. Meanwhile, almost full band absorption can be achieved by regulating the matching thickness, especially efficient absorption at low frequencies (S band and C band). This can be attributed to the balance of impedance matching and attenuation capability achieved by the morphological engineering from nanoneedles to nanosheets. In detail, the introduction of magnetic component and conical nanoneedle antenna structure improved the impedance matching, and the synergistic effect of magnetic loss and strong dielectric loss enhanced the attenuation of electromagnetic waves. Therefore, this study provides a new idea for the design of efficient wave absorbing materials with controlled morphology.