Construction of conductive oxide layer on the surface of lead alloy grid for the long life of lead acid batteries

In this manuscript, surface treatment technology is applied to the positive plate grid of lead-acid batteries to construct stable and capacitive gradient oxide film, in order to increasing the battery capacity and extending the battery life. The deposition process of α-PbO2 on Pb-Ca-Sn alloy is studied by means of anode polarization, galvanostatic polarization and steady-state polarization. By changing the deposition time of different deposition layers to control the deposition thickness, the electrochemical investigation is carried out. The phase composition and surface microstructure of the films are measured tested by means of XRD and SEM, respectively. The experimental results show that the α/β gradient oxide layer have good electrochemical properties. When the thickness ratio of α-PbO2 to β-PbO2 is 1.44, the corrosion potential is 0.160 V and the corrosion current density is 0.084 mA cm−2. Due to the high specific surface area and low charge transfer resistance, the gradient composite has a high capacity (91.81 mAh g−1) in the 0.5 V–1.4 V voltage range and maintains a capacity retention rate of nearly 100% after 100 cycles at the current density of 0.04 A g−1. The matrix is closely bound to the intermediate layer, the intermediate layer and the outer layer without impurity phase.