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

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.

Automated summary

The researchers prepared gamma-MnO2 microspheres using precipitation method and sol-gel process, and successfully achieved a core-shell structure. Due to the synergistic effects between core-shell structure and dielectric loss, these microspheres demonstrated excellent performance in electromagnetic wave absorption field.