Manganese dioxide thin films deposited by chemical bath and successive ionic layer adsorption and reaction deposition methods and their supercapacitive performance

Abstract

In present work, MnO2 thin films with tetragonal and birnessite-phases are deposited using chemical bath deposition (CBD) and successive ionic layer adsorption and reaction (SILAR) methods. The surface morphology of MnO2 film is modified using different deposition parameters. These films are characterized by X-ray diffraction (XRD), fourier transform infrared (FTIR) spectroscopy, field- emission scanning electron microscopy (FE-SEM), Brunarer-Emmett-Teller (BET) and Barrette-Joynere-Halenda (BJH) method. The electrochemical properties are studied using cyclic voltammetry, galvanostatic charge–discharge and electrochemical impedance spectroscopy techniques in 1 M Na2SO4 electrolyte. The CBD method exhibits excellent electrochemical performance with maximum specific capacitance of 757F g−1 at scan rate 5 mV s−1, energy density of 74 Wh kg−1 at power density of 1.5 kW kg−1. The large area solid state symmetric devices fabricated with CBD MnO2 film electrodes exhibit maximum specific capacitance of 128F g−1 with energy density of 14 Wh kg−1 at power density of 0.2 kW kg−1 with capacitive retention of 90% after 5000 CV cycles. Such device is able to glow 211 red LEDs for the period of 160 s, showing it’s possible potential for commercialization.