Fabrication and electrochemical performance of nanoflake MnO2@carbon fiber coaxial nanocables for supercapacitors

Nanoflake MnO 2 @carbon fiber coaxial nanocables were fabricated by a facile electrochemical deposition-oxidation route. The morphology, structure, composition, and pseudocapacitive performance of the obtained composite material were evaluated by scanning electron microscope, X-ray diffraction, X-ray photoelectron spectroscopy, cyclic voltammetry, and galvanostatic charge–discharge measurements. The results show that the nanoflake MnO 2 on the carbon fibers is highly amorphous and hydrous. The nanostructured material shows nearly symmetrical and rectangular CV curves in the scan-rate range from 2 to 50 mV s −1 . When used as electrodes for supercapacitors, the material shows a capacitance of 511.8 F g −1 at 1 A g −1 (based on the mass of MnO 2 ), excellent high-rate capability, and cycling stability.