%0 Journal Article
%T Role of Indium Alloying with Lead as a Means to Reduce the Passivation Phenomena in Lead/Acid Batteries
%A Abdel-Rahman El-Sayed
%A Hossnia S. Mohran
%A Hoda Abdel Shafy Shilkamy
%J International Journal of Electrochemistry
%D 2014
%I Hindawi Publishing Corporation
%R 10.1155/2014/932654
%X The influence of indium content on the anodic behaviour of Pb-In alloys in 4£¿M H2SO4 solution is investigated by potentiodynamic, potentiostatic, chronopotentiometric, and cyclic voltammetric techniques. The composition and microstructure of the corrosion layer on Pb-In alloys are characterized by X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy analysis (EDX), and scanning electron microscopy (SEM). The potentiodynamic and chronopotentiometric curves show that the anodic behavior of all investigated electrodes exhibits active/passive transition. The active dissolution (except for alloy I) and passive currents increase with increasing both In content and temperature. This indicates that the conductivity of the anodic film on Pb-In alloy is enhanced. This study exhibits that indium catalyses the oxidation of Pb (II) to Pb (IV) and facilitates the formation of a more highly conductive corrosion layer on lead. Alloy I (0.5% In) exhibits that the corrosion rate is lower, while the passive current is higher than that of Pb. XRD, EDX, and SEM results reveal that the formation of both PbSO4 and PbO on the surface decreases gradually with increasing In level in the alloy and completely disappear at higher In content (15% In). Therefore, recharge of the battery will be improved due to indium addition to Pb. 1. Introduction Generally, lead and lead alloy were used as the grid material of the lead acid battery, due to their good anticorrosion performance in H2SO4 solution. The use of pure Pb gives rise to strong oxide passive layer formation at the grid/active material interface [1]. This oxide layer is highly stable in the presence of H2SO4 solution. The insulating passive film reduces the anode dissolution, thereby increasing the active life of the battery [2]. However, this also has an undesirable effect of increasing the impedance of the anode after storage for a certain period of time. The increase in the resistance reduces both the reversibility and charging efficiency during subsequent cycles [3]. Passivation of lead and lead alloys is believed to occur by the formation of highly resistive ¦Á-PbO at the interface between the grid and the active material during the oxidation of lead to lead dioxide, which passivate the electrical contact over the boundary layer [4¨C9]. ¦Á-PbO is formed under the lead sulphate layer where the local pH value is close to 9 due to the semipermeable properties of the lead sulphate layer, allowing a flux of H+, OH£¿, and water species, while hindering and ions [9]. The solution of this problem is the addition of tin as
%U http://www.hindawi.com/journals/ijelc/2014/932654/