Electrochemical and spectroscopic methods of characterizing lead corrosion films

Abstract

One of the major causes of failure in lead-acid batteries is the corrosion of the lead current collector at the lead dioxide electrode. The corrosion films which form are complex because changing voltage and concentration gradients across the film favor different reaction products as corrosion progresses. Although excellent studies have been accomplished using mainly electrochemical techniques, X-ray diffraction, electron microscopy, and metallography, development of additional knowledge has been frustrated by the following limitations of these methods: (1) poor resolution of the signals from the many lead compounds which form in the corrosion film, (2) poor spatial resolution of the multiple corrosion product layers which are evident in micrographs of film cross sections, and (3) the inability to analyze the corrosion products in situ to determine the time sequence of species formation. Recently several new approaches to studying lead corrosion films have overcome some of these limitations. These techniques, which include laser Raman spectroscopy, photocurrent and photoacoustic spectroscopy and solid state electrochemistry, are reviewed. Significant results from their application are summarized.