Study on electrochemical properties of gelled electrolytes using nano fumed silica in the presence of some organic additives

A gelled electrolyte is made on the basis of liquid glass and sulphuric acid using nano fumed silica (NFS) in the presence of some other organic additives such as polyacrylamide (PAM) and polypropylene glycol (PPG). Lead-antimony alloy electrodes are prepared to examine the electrochemical properties of manufactured gelled electrolytes through cyclic voltammetric behaviour, electrochemical impedance and polarisation curves. The results from cyclic voltammetric diagrams show that the peak of lead solubility increases while the peak of oxygen evolution decreases due to using nano NFS for gelled electrolytes. Obtained Nyquist diagrams all show that the adsorption process occurs, in which the electrochemical impedance measured in the gelled electrolyte containing NFS increases in comparison with that without NFS. Observing the bigger slope of the outlet branch of oxygen in comparison with that of hydrogen on polarisation curves indicates that the rate of oxygen escape is stronger than that of hydrogen. The results also show that the oxygen overpotential increases while the hydrogen overpotential decreases slightly when NFS is present in gelled electrolytes.