Electrodeposition of morphology- and size-tuned PbO2 nanostructures in the presence of PVP and their electrochemical studies

Micro- and nano-structured lead dioxide (PbO2) have been synthesized by electrodeposition at constant current on Ti substrate. The size and morphology of the PbO2 particles have been tuned by altering the concentration of polyvinylpyrrolidone (PVP) as the surfactant. The prepared samples (PbO2-PVPx, x refers to the percentage of PVP) were characterized using X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray analysis. Based on the compositional characterizations, the samples were found to be composed of alpha- and beta-PbO2 with ionic and organic additives incorporated into their structure. Morphological studies revealed that the particle size and morphology of PbO2 can be controlled by altering PVP concentration. Electrochemical behavior of the prepared samples were investigated in H2SO4 solution by cyclic voltammetry and electrochemical impedance spectroscopy (EIS) techniques. EIS results revealed that the charge transfer resistance significantly decreased in the presence of PVP (48% for the PbO2-PVP3 sample). Based on the obtained results, the presence of PVP during the synthesis greatly influences the electrochemical behavior of the resulting PbO2 film and improves reaction kinetics. The prepared electrodes have been evaluated as cathode materials in H2SO4 electrolyte. Discharge capacity of the optimized sample (in the presence of 3% PVP) was 10 times of that synthesized in the absence of PVP. (C) 2015 Published by Elsevier B.V.