Hierarchical carbon nanotubes@Ni/C foams for high-performance microwave absorption

The construction of special three-dimensional microstructure is becoming an extremely fascinating approach to upgrade the electromagnetic properties of carbon-based microwave absorption materials (MAMs) recently. Herein, we have demonstrated the successful fabrication of a series of carbon nanotubes (CNTs)@Ni/C foams (CNCFs) through two-step pyrolysis processes . It is found that the loading amount of CNTs has an obvious influence on modulating the electromagnetic diameters of CNCFs, and thus effectively tuning their microwave absorption properties . With the relative carbon content of 66.3 wt%, CNCFs-2 exhibits admirable microwave absorption performance , including the effective absorption bandwidth of 5.8 GHz with the absorber thickness of 1.8 mm and the maximum reflection loss intensity of −47.0 dB therein. Electromagnetic analysis reveals that the intrinsic attenuation ability, well-matched characteristic impedance , and multiple reflection effect synergistically work for the excellent reflection loss characteristics of CNCFs-2, which indicates rational microstructure design and appropriate chemical composition regulation are vitally important for the enhancement of microwave absorption performance. We believe these desirable microwave absorption properties can make CNCFs-2 eligible to be a very promising candidate for high-performance MAMs, and this research will provide some inspirations more or less for the development of more advanced carbon-based MAMs in the future.