Effect of Co-adsorption of Ascorbic Acid and Boric Acid Compared to Absorption of Each Single Component on Long-term Oxidationresistivity for the Negative Active Materials of Lead-acid Batteries

A simple and useful technique for preparing an oxidation-resistant film on a Pb electrode is reported herein. A Pb electrode was dipped into a mixed solution containing 1% ascorbic acid and 5% boric acid at 40°C and then air-dried. The Pb electrode was coated with a film on its surface to protect it from oxidation. After three months, the oxide layers on the Pb plate were analyzed by treatment with pure ascorbic acid or boric acid. An oxidized layer was not observed on the plate treated with the mixed solution of ascorbic acid and boric acid; this was confirmed using an electron probe micro analyzer (EPMA). To further analyze the effect of co-absorption, the interaction between ascorbic acid and boric acid in solution was evaluated using a UV-visible spectrometer, and mixed solid samples were analyzed using FT-IR spectrometry.