Galvanostatic synthesis of MnO2 in carbon cloth: an electrochemical impedance spectroscopy study

In the present work, MnO2 was electrodeposited (galvanostatic mode) on carbon cloth (CC) from manganese nitrate and sulfate precursors. Its electrochemical performance was evaluated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), which were used to study the complex behavior of the material. In CV analysis, higher cathodic and anodic loads were obtained for sulfate–MnO2 compared with nitrate–MnO2, whereas in the Nyquist graphs of the EIS technique, the nitrate–MnO2 material obtained larger charge transfer resistance (Rtc) than sulfate–MnO2. In the Bode analysis, the behavior of sulfate–MnO2 was better than that of nitrate–MnO2. because for this analysis, the phase angle is smaller, which is attributed to better pseudocapacitive behavior of sulfate than nitrate. In capacitance and complex power terms, the relaxation time constant obtained was 2.65 s. The real capacitance in C′(ω) was 107 F g−1 for nitrate–MnO2 and 197 F g−1 for sulfate–MnO2, and the intersection of the complex power curves occurred at 70%. The obtained results suggest that these materials are attractive for application in energy storage devices.