Synchronously modulated the morphology and crystal defects of ?-MnO2 for high-performance mono-component electromagnetic wave absorber

Developing mono-component electromagnetic wave (EMW) absorbing materials is desirable owing to their simple preparation methods; thus, it is crucial to investigate EMW absorbing mechanisms. However, owing to the requirements of excellent impedance matching and attenuation capability, EMW material design is considerably challenging. To address these challenges, this study reports an Ag+-doped alpha-MnO2 with a hierarchical structure for EMW absorption. The microscopic morphology and crystal defects are synchronously modulated, resulting in considerable improvement in EMW absorption performance; an optimal reflection loss of-68.6 dB and an effective absorption bandwidth (EAB) of 4.2 GHz are achieved at a thin thickness of 1.43 mm. Thus, thin thickness, enhanced absorption intensity, and widened absorption bandwidth are simultaneously achieved. The regulating effect of Ag+ doping on the morphology of MnO2 and the corresponding EMW absorption mechanism are also discussed. The findings of this study provide new insights for designing mono-component EMW absorbing materials with higher absorption performance.