Hierarchical pomegranate-like MnO@N-doped carbon with enhanced conduction loss and interfacial polarization for tunable and broadband microwave absorption

In order to tackle the electromagnetic pollution caused by the application of electromagnetic wave (EMW) in wireless communication, military industry, and other fields, broadband EMW absorption materials are urgently needed. To achieve this goal, emerging methods resort to constructing multivariate synergistic composites with unique morphology to enhance EMW absorption through diverse loss mechanisms and prominent structural advantage. Herein, a spatially tuned confinement pyrolysis strategy is proposed to design pomegranate-like MnO@NC absorption material. Unique hierarchical structure and more scattering sites are accessed via well-designed one-shell multiple cores nanostructure. N-doped carbon acts as an interwoven conductive network and restricts the movement of EMW in the shell, while nano-MnO acts as an impedance matching phase and interferes with the continuity of EMW. Moreover, the intercalation of dispersed MnO also amplifies the contribution of interfacial effect to EMW absorption, which can be verified by the calculation of the surface work function. The optimized composite possesses a maximum absorption bandwidth of 6.51 GHz at 2.4 mm and its maximum reflection loss reaches − 58.4 dB (d = 2.3 mm). The synthesis of pomegranate-like composite provides a new direction for fabricating advanced carbonate-based EMW absorbers which are toward practical application.