Agminated hollow urchin-like structure of MnO₂/graphite nanosheets composites for improving electromagnetic absorbing properties

Here, agminated hollow urchin-like MnO₂/graphite nanosheets (GNs) composites are successfully synthesized through a simple hydrothermal method. The compositions and microscopic structures are detected by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and Automatic specific surface area analyzer (BET). The electromagnetic (EM) properties are evaluated by a vector network analyzer (VNA). The composites exhibit excellent EM absorption properties, which are largely attributed to the agminated hollow urchin-like structure. And the agminated hollow urchin-like structure of the composites can be changed by adjusting the amount of GNs and KMnO₄. When the dosage of KMnO₄ is 1.896 g and the dosage of GNs is 0.216 g, the minimum reflection loss (RL_min) reaches − 61.13 dB with a 1.8 mm thickness and the bandwidth below − 10 dB is 5.12 GHz with a 1.7 mm thickness. The agminated hollow urchin-like MnO₂/GNs composites with strong absorption and wide frequency band are prepared by a simple method and it can be considered as a promising EM wave absorbing material.