Vertically aligned MnO2 nanostructures on carbon fibers with tunable electromagnetic wave absorption performance

Recently, electromagnetic wave (EMW) absorption materials with enhanced and tunable EMW absorption performance are required in practical applications, and attaining such performance by a simple method remains a vital challenge. In this study, manganese dioxide (MnO2) with controllable structures were vertically grown on carbon fibers (CF) through a hydrothermal method. The sheet-like ([email protected]2-NS) and wire-like ([email protected]2-NW) structures were obtained by merely adjusting the solution chemistries ([K+] and [H+]) and reaction time. The wire-like structure exhibited high attenuation capability due to a larger specific surface area and dielectric resonance, but exhibited a relatively poor impedance matching ratio resulting in inferior EMW absorption performance at low frequencies. However, the sheet-like structure exhibited better EMW absorption performance overall. The minimum reflection loss (RLmin) value of [email protected]2-NS and [email protected]2-NW reached −56.6 dB and −52.9 dB, respectively. Additionally, the EMW absorption performance varies with frequency. [email protected]2-NW performed better in the X-band, while [email protected]2-NS achieved an excellent performance in the C-band. This study provides a simple approach for designing EMW absorption materials with controllable morphologies and for realizing tunable EMW performances.