Contributii privind procesele de oxidare/reducere in sistemul plumb/acid sulfuric,in prezenta sulfatului de bariu

摘要

The paper presents a study using EC-AFM microscopy (Electrochemical Atomic Force Microscopy) on the electrochemical mechanism of oxidation and reduction on the lead/sulphuric acid interface for the negative electrode with inorganic additives in a lead acid battery.The AFM observation combined with cyclic voltammetry was done in situ in sulfuric acid solution on a lead sheet (99.99%),on which a small amount of barium sulfate crystals was fixed by pressing.It was found that barium sulfate provides seeds for the precipitation of lead sulfate crystallites.In addition,it was noticed that lead sulfate crystals are formed more rapidly on the barium sulfate than on the lead sheet during anodic oxidation.The dissolution of the lead sulfate crystals formed on the barium sulfate crystals is very slow during cathodic reduction.The study also demonstrates that EC-AFM microscopy is a powerful tool for observing and studying the intimate processes that occur at the surface of the negative electrode in a lead acid battery during the charge and discharge processes.