Multiple polarization effect of shell evolution on hierarchical hollow C@MnO2 composites and their wideband electromagnetic wave absorption properties

Nanoengineering technology has made great achievements, through the design of useful nanostructures and components, to provide us with more functional materials. Therefore, the ideal performance can be achieved by maximizing the contribution of nanostructures and components. As a typical material, core-shell material has been widely studied in order to find more possibilities in the nanoengineering applications. In this work, a designable core-shell composite material with graphitized tunable hollow carbon sphere as the core and sheet-like MnO2 particles as the shell is developed. The size and shell thickness of the core-shell shaped [email protected]2 was nearly 230, 40 nm, respectively. The correlation among shell-evolution, graphitized-tuned carbon core and their corresponding dielectric response ability has been well analyzed. The hollow carbon [email protected]2 with desirable real and imaginary permittivity (ε'/ε'') can be obtained in order to achieve the optimized electromagnetic (EM) absorption performance. One optimal reflection loss of −53.5 dB is gained at the thickness of 1.5 mm and the corresponding frequency region with RL < −10 dB is around 4.8 GHz. The method demonstrated here for successfully use shell-evolution combined with hollow structure to boost dielectric response towards wanted EM performance has been demonstrated as a useful strategy for the preparation of broadband electromagnetic wave absorbers.