In lead-acid batteries, sulfuric acid (H₂SO₄) serves several critical roles.
- Electrolyte: Sulfuric acid acts as the medium for the ionic exchange between the lead dioxide (PbO₂) on the positive plate and the sponge lead (Pb) on the negative plate. This ionic movement is essential for the flow of electric current.
- Chemical Reaction: During the discharge cycle, sulfuric acid reacts with lead dioxide and lead to form lead sulfate (PbSO₄) on both plates and water (H₂O). This reaction releases electrical energy that powers the connected devices.
- Ion Conduction: Sulfuric acid dissociates into hydrogen ions (H⁺) and sulfate ions (SO₄²⁻), which are crucial for conducting ions between the electrodes, maintaining the chemical balance necessary for the battery’s operation.
- Regeneration: During the charging cycle, the reverse reaction occurs. Electrical energy is used to convert lead sulfate and water back into lead dioxide, sponge lead, and sulfuric acid, thus regenerating the battery for further use.
