A design of core-shell structure for γ-MnO2 microspheres with tunable electromagnetic wave absorption performance

摘要

Manganese dioxide (MnO2) has been widely utilized in the electromagnetic wave (EMW) absorption field because it exhibits numerous crystal types including alpha-MnO2, beta-MnO2, gamma-MnO2, and delta-MnO2, and is environ-mentally friendly. To enhance the EMW absorption performance of this material, we combined the precipitation method and calcination process to obtain gamma-MnO2 microspheres, and developed a core-shell structure of gamma-MnO2@SiO2 and gamma-MnO2@SiO2@TiO2 microspheres via the sol-gel process. Based on the synergistic effects between the core-shell structure and dielectric loss, gamma-MnO2@SiO2 with a thickness of 2.85 mm achieved the minimum reflection loss of-60.2 dB, demonstrating that these microspheres are excellent candidates for EMW absorbers.

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