Study of charge acceptance for the lead-acid battery through in situ EC-AFM observation - influence of the open-circuit standing time on the negativeelectrode

An influence of the open-circuit standing time after oxidation of the lead electrode was investigated for understanding charge acceptance of the negat ive electrode of a lead-acid battery. It was confirmed by a potentiostatic transient experiment that charge acceptance of the lead electrode heavily d epended on the standing time before charging, and charge acceptance decreas ed if the standing time was longer. This tendency was conspicuous at the in itial period of the reduction process in particular. When the behavior of t he lead electrode surface during the open-circuit standing after oxidation was observed by in situ electrochemical atomic force microscope (EC-AFM), i t was found that some lead sulfate crystals gradually grow with time to big ger crystals having a smooth surface, retaining basically its morphology of previous one. We have concluded that the standing time dependence of the c harge acceptance is caused by this behavior of the crystals. Also, it was c onfirmed that charge acceptance of a valve regulated lead-acid (VRLA) batte ry with different standing times can be explained by result of the potentio static transient test and the EC-AFM observation. (C) 2001 Elsevier Science B.V. All rights reserved.