Electrochemical Behaviors of Powder-Processed Pb-Ag Anodes

Pb-based anodes with different Ag contents (0 wt.%, 0.2 wt.%, 0.4 wt.%, 0.6 wt.%, 0.8 wt.%) were prepared by the powder-processed (PP) method. Electrochemical behaviors of Pb-Ag anodes in the sulfuric acid solution were studied by performing tests of cyclic voltammetry, galvanostatic polarization and anodic polarization. Morphologies and phases of the anode oxide layer after polarization were studied by scanning electron microscopy (SEM) and x-ray diffraction (XRD), respectively. When the Ag fraction is > 0.4 wt.%, stable oxygen evolution potentials of PP Pb-Ag anodes are lower than those of the cast Pb-Ag (0.6 wt.%) anode. As the Ag fraction increases, the stable potential of the alloy anode decreases while average grain sizes of oxides on anode surfaces increase. However, when the Ag content is > 0.4 wt.%, its effect on surface grain growth becomes insignificant.