▎ 摘　　要

In the present contribution, grapheme-manganese oxide hybrid nanostructures (G/MnO2) were synthesized via rapid and facile microwave irradiations technique. The as-prepared samples were investigated and characterized by standard characterization techniques such as scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD) and Raman spectroscopy. Structural studies using XRD confirmed the monoclinic lamellar structure of birnessite MnO2. Moreover, morphological investigations reveal the uniform and homogenous decoration of MnO2 needles on the surface of GO nanosheets with average size of 190 nm. Due to the full coverage of MnO2 over the graphene nanosheets surface, the characteristic Raman "D" and "G" band were disappeared in the case of G/MnO2. Electrical properties were investigated using broadband dielectric spectroscopy (BDS). The obtained results reveals that both the conductivity and energy storage capability of the G/MnO2 composite improved since the measured dielectric constant for the G/MnO2 hybrid decreases with increasing frequency. The obtained results including electrical, morphological and structural properties indicate the promising applications of the G/MnO2 hybrid. These present findings are applicable in modern high-frequency electronics devices and energy storage devices.