Extending the life of maintenance-free lead/acid batteries by etching of grids in sodium hydroxide

摘要

The surfaces of lead–calcium–tin grids etched in NaOH have been characterized by using X-ray photoelectron spectroscopy (XPS) and environmental scanning electron microscopy (ESEM). It is shown that the basic lead carbonate phase, hydrocerussite, present on the surfaces of lead–calcium–tin grids is removed via etching in NaOH, due presumably to the dissolution of lead(II) salts as water soluble lead(II) complexes. Charge/discharge cycling data for non-antimonial batteries fabricated by using untreated and grid etched 2 V cells have demonstrated that the removal of grid surface hydrocerussite diminishes the rate of premature capacity loss displayed by non-antimonial batteries in the early stages of cycling. Furthermore, scanning electron microscopy (SEM) of the corrosion layers of positive plates for untreated and grid etched cells, in the initial stages of cycling, demonstrated that the removal of grid surface hydrocerussite ameliorates the problem caused by passivation of the grid corrosion layer through the formation of an uninterrupted underlayer of PbO.