ABSTRACT
A facial green co-electrodeposition of manganese oxide (MnOx)/reduced graphene oxide (RGO) supported on indium tin oxide (ITO) glass has been studied for supercapacitors. Graphene oxide (GO) is firstly synthesized from graphite by a modified Hummers method. Then the MnOx/RGO films were prepared by cyclic voltammetery (CV) from an aqueous mixture containing GO and manganese acetate. Characterization of the prepared MnOx/RGO electrodes were performed by XRD, FESEM, and FTIR. The capacitive behaviors of the MnOx/RGO electrodes were examined by CV, galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS). The characterized analyses indicate that both manganese oxide and RGO can be successfully co-deposited on ITO glass. Manganese oxide is deposited in the morphology of nano particles and curved nano rods, while RGO is in flaky structure. Both MnO2 and Mn2O3 without observable crystallinity are present in the deposited films. The Mn-O-C bonds are probable to exist in the samples. Appropriate modification of the manganese oxide films by co-electrodeposition of RGO can effectively improve their morphology, porosity, and electrical conductivity and reduce the electrolyte diffusion path, consequently enhancing the specific capacitance by about 100% at a scan rate of 100 mVs-1.
AT A. applied as the formace presented for the The electrical properties of the poly(3,4-thylenedioxythiophene): poly(styrenesulfonate) (PEDOT: PSS) are strongly dependent on their chemical and physical structures. The mechanism of enhancement conductivity in the PEDOT: PSS films by adding various molar concentrations of H2SO4 were further studied. The sheet resistance of the doped PEDOT: PSS film enhanced with increasing the ratio of H2SO4, but it drops after the maximum sheet resistance. The reason for this phenomenon is that the H2SO4 was reacted with sorbitol preferentially. The non-conductive anions of some PSS- were substituted by the conductive anions of HSO4 - when the residual H2SO4 reacted with PSS. After the H2SO4 doped, the sheet resistance of H2SO4-doped PEDOT: PSS film is improved nearly 36%; the surface roughness is reduced from 1.268 nm to 0.822 nm and the transmittance is up to 91.6% in the visible wavelength range from 400 to 700 nm. However, the H2SO4-doped PEDOT: PSS films can be used as the transparent conductive electrode of optoelectronic devices in the future.
