ABSTRACT

Direct and pulse current electrodeposition techniques were applied for preparation of novel electro-active manganese oxides. The influences of Ag doping and addition of cetyltrimethylammonium bromide (CTAB) on electrochemical properties were discussed. The morphology and structure of the electrodes are studied by different techniques including field emission scanning electron microscopy (FE-SEM), contact angle and X-ray photoelectron spectroscopy (XPS). Electrochemical behavior of the samples are investigated by cyclic voltammetry (CV), constant current charge-discharge (CC), and electrochemical impedance spectroscopy (EIS). The specific capacitances were measured to be 269, 315, 435, 442, 480 and 508 F g^-1 for M-g, M-p, MC-g, MC-p, MCA-g and MCA-p (current density = 1 A g^-1), respectively. The MCA-p exhibit high specific capacitance, excellent cycling stability (only 7.5% loss after 1000 cycles at 1 A g^-1), and high energy densities (71 Wh kg^-1). Ag doping and addition of CTAB which provides more active sites for the pseudocapacitive reactions.

Keywords: supercapacitor; MnO2; CTAB; Ag doping; pulsed current