A comparative study of sequentially layer-deposited and co-deposited Co-Mn oxides as potential redox capacitors

Layers of cobalt and manganese oxides were co-deposited (CMO1) or deposited by on top of each other (CMO2, CMO3) or next to each other (CMO4) by potentiostatic method onto stainless steel substrate. Deposition potentials of 1 and -1 V for the anodic and cathodic depositions were employed. Specific capacitance values for (CMO1), (CMO2), (CMO3) and (CMO4) samples were found to be 48 Fg
^-1
, 38.5 Fg
^-1
, 78 Fg
^-1
and 40.6 Fg
^-1
, respectively. The usefulness of the electrodes was characterized by cyclic voltammetry (CV), charge/discharge cycling, and electrochemical impedance spectroscopy (EIS) in 2M NaOH electrolyte for redox supercapacitor applications. (CMO3) presented the best charge/discharge behavior with no voltage drop due to ohmic resistance; although the most steady current observed in the course of voltammetry was due to (CMO2). The evaluated double layer and specific capacitances for (CMO1) according to the impedance studies were 1.75 and 47.5 Fg
^-1
, respectively.