A lead acid battery consists of a negative electrode made of spongy or porous lead. The lead is porous to facilitate the formation and dissolution of lead. The positive electrode consists of lead oxide. Both electrodes are immersed in a electrolytic solution of sulfuric acid and water.
Voltage of lead acid battery upon charging. The charging reaction converts the lead sulfate at the negative electrode to lead. At the positive terminal the reaction converts the lead to lead oxide. As a by-product of this reaction, hydrogen is evolved.
Although lead acid batteries are an ancient energy storage technology, they will remain essential for the global rechargeable batteries markets, possessing advantages in cost-effectiveness and recycling ability.
The lead–acid battery is a type of rechargeable battery first invented in 1859 by French physicist Gaston Planté. It is the first type of rechargeable battery ever created. Compared to modern rechargeable batteries, lead–acid batteries have relatively low energy density. Despite this, they are able to supply high surge currents.
Sulfation prevention remains the best course of action, by periodically fully charging the lead–acid batteries. A typical lead–acid battery contains a mixture with varying concentrations of water and acid.
Lead acid batteries store energy by the reversible chemical reaction shown below. The overall chemical reaction is: P b O 2 + P b + 2 H 2 S O 4 ⇔ c h a r g e d i s c h a r g e 2 P b S O 4 + 2 H 2 O At the negative terminal the charge and discharge reactions are: P b + S O 4 2 - ⇔ c h a r g e d i s c h a r g e P b S O 4 + 2 e -