Lead Dioxide Electrocrystallization from Nitrate and Methanesulfonate Electrolytes: The Influence of Various Dopants on Initial Stages

Integrated data about the influence of dopants with different nature on crystallization rate constants and crystal shape have been presented in this work. It was obtain that there is an increase of current delay, corresponding to the induction period on chronoamperometric curves in the presence of cationic additives in the deposition electrolyte that indicates difficulties in initial stages of lead dioxide phase formation. The crystallization occurs through the progressive mechanism. The preferred geometric shape of formed crystals at 2D nucleation from electrolytes containing cationic additives is cone. And upon crystallization from electrolytes containing complex ions additives geometric shape changes on a cylinder. For nitrate electrolytes there is a change in the mechanism from progressive on instantaneous at high concentrations of added surfactants. The preferred form of crystals at 2D nucleation in the presence of surfactant additives in nitrate electrolytes is semi-spheroid, and in the case of methanesulfonate electrolytes cylinder becomes the preferred form of crystals. In the case of suspension electrolytes at 2D nucleation the formation of three main forms of crystals is possible depending on the polarization.