Modified electrodes based on MnO2 electrodeposited onto carbon felt: an evaluation toward supercapacitive applications

This work describes the electrochemical characterization toward supercapacitive properties of a modified electrode based on MnO2 electrodeposited onto carbon felt electrode (CFE/MnO2). Raman analysis confirmed the electrode modification and FEG-SEM images showed a 3D network structure with a homogeneous deposit of the MnO2 film. The morphology of the electrodeposited film showed to be dependent on the electrodeposition applied potential and time. Cyclic voltammetry and galvanostatic charge/discharge curve results showed that the charge storage process is reversible and a combination of EDLC and pseudocapacitive behavior. Under optimized conditions (1.2 V and 600 s), the modified electrode presented a specific capacitance of 541 F g−1 in an applied current density of 0.2 A g−1, which was attributed to a favored accessibility of the electrolyte on the film porous due to morphological issues. Besides, the modified electrode revealed a good capacitance retention of 80% in an applied current density of 1.0 A g−1 after 1000 cycles.