Effect of phosphoric acid on the performance of low antimony grid of Pb‐acid cell under constant current charging and discharging

Abstract

Effect of phosphoric acid on the performance of Pb-1.7%Sb grid of lead-acid cell is studied in 5 M H 2 SO 4 by cyclic galvanostatic polarization and impedance spectroscopy. An increase in capacitance to a maximum is recorded during the initial stages of the electro-reduction of PbO 2 into Pb(II) compounds and attributed to concurrent compositional and dimensional changes. These changes include removal of O 2 bubbles, insertion of large amounts of H 2 SO 4 and H 2 O. Efficiency of PbO 2 formation decreases, while its rate of self-discharge increases with increasing the charging current and in the presence of H 3 PO 4 . The charge capacity increases with increasing the discharging current due to the decrease in the self-discharge. The charge capacity is lower in the presence of H 3 PO 4 . On increasing the cycle number, the corrodibility of the grid increases, because more layers of the surface Pb are involved in the self-discharge. H 3 PO 4 significantly retards the effect of cycle number.

Effect of boric acid on corrosion and electrochemical performance of Pb-0.08{\%} Ca-1.1{\%} Sn alloys containing Cu, As, and Sb impurities for manufacture of grids of lead-acid batteries

“…Peak A2 is most pronounced for alloy G-Sb. The potential of peak A2 is close to the equilibrium potential of the following redox processes: 34,43 3P bOP bSO 4…”

“…Stage e: The electro-reduction of PbO 2 to PbSO 4 at 1.0 V. 34,43 C increases in the initial stage of reduction to a maximum and then it decreases, while R stays low. The initial increase in C is attributed to an increase in the dielectric properties of the PbO 2 layer as a result of the concurrent OER and involvement of O 2 species in the growing PbO 2 layer.…”

“…This is mainly attributed to the strong contribution of the self-discharge of PbO 2 with the underlying Pb in the alloys. 34,35 Moreover, the anodic process at A' adds more Pb 2+ species. The self-discharge occurs spontaneously according to the following comproportionation reaction: 34,35,43,44 P bO…”

“…21 The effect of H 3 PO 4 on the efficiency of formation of PbO 2 on the positive grid during charging was found to depend on the charging conditions; some conditions increased the efficiency, 16,25 while others showed the opposite effect. 21,23,34 Citric acid as an electrolytic additive was reported to decease the self-discharge of lead-acid batteries by the suppression of PbO 2 reduction. 36,37 Little attention has been given to boric acid as an electrolytic additive.…”

Electrochemical and Metallurgical Behavior of Lead-Aluminum Casting Alloys as Grids for Lead-Acid Batteries

“…The lead plates which constitute this battery are very malleable, fragile and cannot resist, as it should, facing the corrosivity of the concentrated electrolyte which is made of 4 M H2SO4. Also, the battery suffers from the sulfation phenomena, which is characterized by the formation of a non-porous and impermeable layer of PbSO4 on the surface of the metal, thus preventing any possible reaction between lead and H2SO4 [1][2][3][4]. For all these reasons, it is imperative to find alternative solutions to reinforce these plates and make them more resistant to mechanical shocks as well as to electrochemical corrosion.…”