Lightweight Fe-doped MnO2@C hollow nanocubes for ultra-broadband microwave absorption

Abstract

The rational structural design and compositional merits as well as the synergistic coupling effect can break the properties of single material and broaden the microwave absorption band. Herein, the unique lightweight Fe-doped MnO2@C hollow nanocubes are rationally designed and successfully synthesized via a scalable wet chemical process and polydopamine coating followed by high-temperature calcination. By virtue of the unique structure and compositional merits, the as-obtained Fe-doped MnO2@C hollow nanocubes (Fe–MnO2@C-HNBs) displayed notable microwave absorption performance (MAP), simultaneously achieving ultra-broad absorption bandwidth and strong absorption characteristics at a low thickness of 2.3 mm (the reflection loss of −41.02 dB and the effective absorption bandwidth of 5.86 GHz). Surprisingly, the effective absorption bandwidth (RL < −10 dB) could reach up to 8.08 GHz and the minimum reflection loss (RLmin) was −38.20 dB at the thickness of 2.7 mm. The results further confirmed that the excellent microwave attenuation ability of the as-prepared Fe–MnO2@C-HNBs composites benefitted from the special “air@core-shell” structure and multiple heterointerfaces as well as multi-component recombination. These results demonstrated that the as-obtained Fe–MnO2@C-HNBs composites could be attractive candidates for broadband microwave absorption materials.