International Journal of Energy Research, Vol.44, No.1, 158-170, 2020
Galvanostatic synthesis of nanostructured Ag-Ag2O dispersed PPy composite on graphite electrode for supercapacitor applications
Polypyrrole (PPy) and nanostructured Ag-Ag2O were co-deposited galvanostatically on the Ag-intercalated graphite electrode in acetonitrile/TBABF(4) solution with AgBF4, Py, HBF4, H2O, and sodium carboxymethyl cellulose (CMC). The effects of additives and intercalation on the capacitive behaviors of PPy-Ag-Ag2O-CMC composite (4.0 mg/cm(2)) were studied in H2SO4 (0.1 M) solution by using cyclic voltammetry and electrochemical impedance spectroscopy methods. The composite coating was characterized using X-ray photoelectron spectroscopy, transmission electron microscopy, X-ray diffraction (XRD), Brunauer, Emmett, and Teller, and scanning electron microscopy (SEM) energy dispersive X-ray spectroscopy. The incorporation of nano-sized Ag-Ag2O particles and CMC into the composite has significant impacts on the morphology, which also greatly influences the capacitive performance. XRD and SEM studies showed that the electrochemical intercalation of silver in acetonitrile medium provided partially exfoliated surface of graphite, thus the capacitive properties further enhanced. The capacitive properties of the composite coating were also tested using the galvanostatic charge-discharge method. The specific capacitance of the composite coated electrode was calculated as 500 F/g at 2.0 A/g in H2SO4 solution by subtracting the capacitance of bare graphite electrode. Asymmetric and symmetric supercapacitor configurations were utilized to examine the capacitive performance of PPy-Ag-Ag2O-CMC composite (10 mg/cm(2)) on Ag-intercalated graphite paper. The asymmetric supercapacitor providing a power density of 0.51 kW/kg at 2.0 A/g and an energy density of 23.6 Wh/kg maintains 62% of its capacitance after 5000 cycles.