Electrodeposition of Nano-Structured PbO2 on Glassy Carbon Electrodes by FFT Continuous Cyclic Voltammetry

Nano-structured lead dioxide was prepared by an easy and fast continuous cyclic voltammetric technique. The prepared nano-structured lead dioxide films were ultimately aimed at producing cathodes with improved electrocatalytic activity and stability for the lead acid batteries. During the measurements, the potential waveform, which consisted of the potential step for electrodeposition and potential ramp, was continuously applied on a glassy carbon disk electrode. Different parameters such as step potential and its duration time, and also scan rate of continuous cyclic voltammetry were optimized to obtain higher capacity. Results comparison of the voltammetric experiments previously reported and those from laboratory-designed test cells have confirmed a higher charge/discharge performance of our electrodeposited samples towards the PbO2/PbSO4 transformation in aqueous sulfuric acid solutions. The enhanced characteristics of this sample is attributed to its special morphology due to formation of nano structure at high scan rates, as confirmed by SEM. Maximum current efficiency was observed when step potential and time were equal to 1400mV and 1700ms, respectively, at a scan rate of 4000 mVs-1. Analysis of electrochemical impedance spectroscopy (EIS) data revealed that the charge transfer resistance is decreased by a change in scan rate as the FFT continuous cyclic voltammetric tests showed. A higher overpotential for oxygen evolution reaction was also observed for electrodes prepared in this electrochemical technique in sulfuric acid solution. The morphology of electrodeposited oxide are very different from those of oxide forming in lower scan rates, due to the high surface area obtained as well as high connectivity between particles resulted in increased discharge capacity.