Investigation of N-VACNT@MnO2 nanocomposite structure as supercapacitor electrode material

In this thesis firstly, nitrogen-doped vertically aligned carbon nanotubes on carbon fabric were synthesized by FCCVD method, and secondly, MnO2 nanosheets were grown on them by hydrothermal method, and CC@N-VACNT@MnO2 composite structure was obtained. Parameters such as specific capacitance, energy density, and cycle stability of this composite electrode material were investigated for supercapacitor application. In the GCD measurements performed separately in a three-electrode test cell using 1 M Na2SO4 electrolyte, the specific capacitance of N-VACNTs at a current density of 0.5 A g-1 was calculated as 53.7 F g-1, while the specific capacitance of the N-VACNT@MnO2 electrode structure was calculated as 497 F g-1. However, while the N-VACNT electrode has 99% of its initial specific capacitance after 10.000 charge/discharge cycles taken at a current density of 10 A g-1, the N-VACNT@MnO2 electrode structure exhibited excellent cycle stability with 76% of its initial specific capacitance after 10 charge/discharge cycles. In addition, for the asymmetrical supercapacitor, the specific capacitance was obtained as 59.4 F g-1 at a current density of 1 A g-1. In addition, it has been observed that this supercapacitor maintains 84% of its specific capacitance at the end of 10,000 cycles in the 1.7 V potential range. While the energy density was 24.7 Wh kg-1, the power density was found to be 15.7 kW kg-1.