Lead sulfate electrode

Lead styphnate, 10 729 Lead sulfate electrodes, standard potential, 3 413t... 

In order to recharge the battery, i.e., to force the reaction in the opposite direction, energy input is necessary. In the process, lead or lead oxide will reform at the lead sulfate electrodes. 

H. Gdhr, J. Sdllner, and H. Weinzierl [1983] Kinetic Properties of Smooth and Porous Lead/Lead Sulfate Electrodes in Sulfuric Acid during Charging and Discharging, Proc. 34th ISE Meeting, Erlangen, Poster 0715. 

At the cathode, or positive electrode, lead dioxide [1309-60-0] Pb02, reacts with sulfuric acid to form lead sulfate [7446-14-2] PbSO, and water in the discharging reaction... 

The mercurous sulfate [7783-36-OJ, Hg2S04, mercury reference electrode, (Pt)H2 H2S04(y ) Hg2S04(Hg), is used to accurately measure the half-ceU potentials of the lead—acid battery. The standard potential of the mercury reference electrode is 0.6125 V (14). The potentials of the lead dioxide, lead sulfate, and mercurous sulfate, mercury electrodes versus a hydrogen electrode have been measured (24,25). These data may be used to calculate accurate half-ceU potentials for the lead dioxide, lead sulfate positive electrode from temperatures of 0 to 55°C and acid concentrations of from 0.1 to Sm. 

PIa.tes, Plates are the part of the cell that ultimately become the battery electrodes. The plates consist of an electrically conductive grid pasted with a lead oxide—lead sulfate paste which is the precursor to the electrode active materials which participate in the electrochemical charge—discharge reactions. 

Paste Mixing. The active materials for both positive and negative plates are made from the identical base materials. Lead oxide, fibers, water, and a dilute solution of sulfuric acid are combined in an agitated batch mixer or reactor to form a pastelike mixture of lead sulfates, the normal, tribasic, and tetrabasic sulfates, plus PbO, water, and free lead. The positive and negative pastes differ only in additives to the base mixture. Organic expanders, barium sulfate [7727-43-7] BaSO carbon, and occasionally mineral oil are added to the negative paste. Red lead [1314-41 -6] or minium, Pb O, is sometimes added to the positive mix. The paste for both electrodes is characterized by cube weight or density, penetration, and raw plate density. 

PbO TbSO H20. If the temperature is elevated to >57° C, the result is coarse tetrabasic lead sulfate, 4PbO TbSO, crystals. This is especially critical for the positive electrode where tribasic sulfate converts readily to Pb02 during battery formation but tetrabasic sulfate does not (93). 

Lead oxide (PbO) (also called litharge) is formed when the lead surface is exposed to oxygen. Furthermore, it is important as a primary product in the manufacturing process of the active material for the positive and negative electrodes. It is not stable in acidic solution but it is formed as an intermediate layer between lead and lead dioxide at the surface of the corroding grid in the positive electrode. It is also observed underneath lead sulfate layers at the surface of the positive active material. 

The charge-discharge reaction of the negative electrode corresponds to curve A in Fig. 1, but the Pb2+ ion activity is now determined by the solubility of lead sulfate (PbS04). Thus Eq. (12) has to be modified into... 

Figure 3. Active material of a lead dioxide electrode, charged on the left, discharged on the right. The charged state shows the typical "lump" structure in the discharged state lead sulfate crystals dominate [151-...

After an initial overshoot, a constant potential is attained at the electrode (Fig. 16.4) this is governed by the kinetics of lead sulfate crystallization. After some time, the potential begins to shift in the positive direction, slowly at first bnt then rapidly. This... 

This mechanism is followed in particular in the reactions of lead sulfate in the electrodes of lead-acid storage batteries. At the negative electrode. 

The lead and lead dioxide electrodes sit in the sulfuric acid solution. The solution connects the electrodes chemically. At the negative electrode, lead reacts with sulfate ions to produce lead sulfate and an electron ... 

The inner PbO layer is formed because of the impermeability of PbS04 layer for S04 ions only Pb +, OH , and H+ ions can transfer across this film. Thus, in the course of anodic scan, H+ ions can flow from the reaction site into solution, resulting in alkaline medium formation near the electrode surface. With increasing H2SO4 concentration, the lead sulfate layer is more compact and electrolyte ions... 

During discharge, both electrodes become coated with insoluble lead sulfate, and if this coating is allowed to become excessive, the lead sul-... 

Bottcher s accumulator — This was an - accumulator with a lead and a zinc electrode in a zinc sulfate electrolyte. Upon discharge zinc ions are reduced to the metal, and lead is oxidized to lead sulfate. These processes are reversed upon charging. 

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