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

Abstract

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 (CF@MnO2-NS) and wire-like (CF@MnO2-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 CF@MnO2-NS and CF@MnO2-NW reached −56.6 dB and −52.9 dB, respectively. Additionally, the EMW absorption performance varies with frequency. CF@MnO2-NW performed better in the X-band, while CF@MnO2-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.