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

Abstract

Layers of cobalt and manganese oxides were codeposited or deposited on top of each other or next to each other 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 in the range of 38.5-78 F g −1 were found with cobalt oxide on top of manganese oxide having the lowest and manganese oxide on top of cobalt oxide having the highest capacitances. The usefulness of the electrodes was characterized by cyclic voltammetry, charge-discharge cycling, and electrochemical impedance spectroscopy in 2 M NaOH electrolyte for redox supercapacitor applications. The latter presented the best charge/discharge behavior with no voltage drop due to lower ohmic resistance in prepared substrate; although the steadiest current observed in the course of voltammetry was due to the former. The evaluated double layer and specific capacitances for codeposited sample according to the impedance studies were 1.75 and 47.5 F g −1 , respectively, being in good agreement with voltammetric measurements.

Analysis of optical dispersion parameters and electrochromic properties of manganese-doped Co3O4 dendrite structured thin films

“…4 and -0.6 to +0.8 V for Mn-doped Co 3 O 4 films. Gobal and Jafarzadeh[47] have inferred the similar type of variation for manganese deposited over cobalt oxide layers where the enhancement in the current density of the anodic and cathodic peaks at the cost of the reduction in the potential window was observed. Similar type of observation was also made byNaveen and …”

Layer by Layer Ex-Situ Deposited Cobalt-Manganese Oxide as Composite Electrode Material for Electrochemical Capacitor

“…In this case, an electrode containing mixed metal oxides performs better than a single transition metal oxide when it is used as the electrode in a supercapacitor [ 15 ]. For instance, F. Gobal and S. Jafarzadeh [ 16 ] employed the deposition method to obtain binary cobalt-manganese oxides on stainless steel substrate, and the ex situ deposited metal oxide showed higher specific capacitance than a single deposited metal oxide. However, the morphology changes and the effect of the second layer have not been studied.…”