Effect of Ag-Doping on the Capacitive Behavior of Amorphous Manganese Dioxide Electrodes

Abstract

Amorphous MnO 2 and Ag-doped MnO 2 thin films were galvanostatically deposited on a polished stainless steel substrate from 20 mM KMnO 4 aqueous solutions without and with AgNO 3 additions at cathodic current density of 1 mA/cm 2 for the application in electrodes of electrochemical supercapacitors. The supercapacitive properties of the deposited thin films have been studied in 0.5 M Na 2 SO 4 electrolyte by cyclic voltammetry, impedance spectroscopy, and charge-discharge measurement techniques. The Ag-free MnO 2 film showed better capacitive behavior and lower charge transfer resistance compared to the Ag-doped MnO 2 films. The specific capacitance and charge transfer resistance values for Ag-free MnO 2 films were 160 F/g at a scan rate 10 mV/s and 3.87 Ω, respectively. Cyclic stability using charge-discharge measurement technique indicates the excellent stability of Ag-free MnO 2 films and its possible use as a low cost electrode for supercapacitor applications.

Nanoflake Manganese Oxide and Nickel‐Manganese Oxide Synthesized by Electrodeposition for Electrochemical Capacitor

“…Morphology Structure BET /m 2 ⋅g −1 Capacitance , F/g Hydrothermal [17] P l a t e l i k e , n a n o r o d -MnO 2 100-150 72-160 (200 mA⋅g −1 ) High viscosity process [18] R o d -s h a p e d -MnO 2 , -MnO 2 -3 8 9 ( 1 0 m V ⋅s −1 ) Room temperature precipitation [19] R o d -s h a p e d -MnO 2 -2 0 1 Low temperature reduction [20] N a n o fl o w e r C u b i c M n O 2 (Fd3m) 225.9 121.5 (1000 mA⋅g −1 ) Sol-gel process [21] N a n o r o d s -MnO 2 317 (100 mA⋅g −1 ) following studies have focused on varying the deposition parameters in order to achieve the enhanced electrochemical performance [7][8][9][10][11][12][13]. The MnO 2 thin films can be prepared by anodic/cathodic electrodeposition.…”

MnO2/carbon nanowall electrode for future energy storage application: effect of carbon nanowall growth period and MnO2mass loading

“…Due to their excellent electrocatalytic activity than carbon materials, transition metal oxides have been extensively used in many electrochemical applications including supercapacitors during the past decades. [8][9][10][11][12][13][14][15][16][17][18][19][20][21] MnO 2 , compared to the other transition metal oxides, is the most thoroughly investigated for pseudocapacitors on the basis of its high theoretical specic capacitance of 1370 F g À1 , relatively low cost and environmentally benign nature. [22][23][24][25][26][27] Being limited by its poor electrical conductivity, the theoretical specic capacitance of MnO 2 has rarely been achieved in any experiment.…”

Reduced graphene oxide decorated on MnO2nanoflakes grown on C/TiO2nanowire arrays for electrochemical energy storage

“…The peak at approximately 540 cm À1 corresponds to the Mn-O bond. 38 The Raman spectrum of RGO/MnO 2 /C/TiO 2 is shown in Fig. 3b.…”