Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1667130 | Thin Solid Films | 2012 | 8 Pages |
Amorphous nanostructured MnO2 film was anodically deposited onto economical duplex stainless steel substrate. The obtained MnO2 film was characterized by X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray spectroscopy for microstructural, morphological, and compositional studies. The capacitive behavior was systematically investigated by cyclic voltammetry, charge–discharge cycling and electrochemical impedance spectroscopy (EIS) in 1 M Na2SO4 electrolyte at different operating temperatures ranging from 20 to 60 °C. The specific capacitance (SC) was improved with an increase of operating temperature, and the highest SC of 398 F/g was achieved at a scan rate of 10 mV/s and operating temperature of 60 °C. The mechanism of SC improvement at elevated operating temperature was investigated using EIS. With an increase of operating temperature, the conductivity of electrolyte was improved, and the charge-transfer resistance (Rct) was decreased. The temperature dependence of 1/Rct follows an Arrhenius equation. The MnO2 film was electrochemically activated at 60 °C due to the formation of NayMnO2 after discharging.
► MnO2 was anodically deposited onto duplex stainless steel substrate. ► The effect of operating temperature on the performance of MnO2 was studied. ► The mechanism of specific capacitance improvement was investigated.