Self-template and in-situ polymerization strategy to lightweight hollow MnO2@polyaniline core-shell heterojunction with excellent microwave absorption properties

Highlights: • The multi-interface structure MnO₂@PANI is prepared by a mild self-template method. The surface modification enhanced the affinity of MnO₂ to AN, which made it possible to obtain the core-shell structure of MnO₂@PANI successfully. • A series of MnO₂-based products with multi-interface structure are obtained by simple self-template oxidation-etching strategy. The multi-interface structure is conducive to enhance the attenuation loss of polarization effect on electromagnetic wave. • RL_min of H-MnO₂@PANI is −52.06 dB at 8.48 GHz, and it has a broadband absorption of 4.56 GHz. Its excellent microwave absorption performance is attributed to the synergistic effect of conductivity loss, interface polarization and multiple reflection loss. Nowadays, high-frequency electromagnetic pollution makes the lightweight and high-efficiency absorption materials become the research hotspot. In this paper, the hollow structure MnO₂@PANI microsphere composite was reasonably synthesized by self-template strategy and in-situ polymerization. Coating conductive polyaniline (PANI) on the modified surfaces of MnO₂ microsphere not only can improve the impedance matching and microwave absorption ability, but also solve the drawback of low loss intensity as well as narrow absorption band of pure MnO₂. The conductive polymer PANI conductance loss, MnO₂-PANI multiple interfacial polarization and multiple reflection loss synergy endows hollow MnO₂@PANI microsphere excellent microwave absorption performance. The RL_min of hollow MnO₂@PANI microsphere is −52.06 dB at 8.48 GHz and has a wide absorption of 4.56 GHz. Those positive results show that the pure dielectric MnO₂@PANI microsphere material with a multi-interface hollow core-shell structure prepared from a template is a lightweight and efficient absorbent.