Lead combines with SO 4 to create PbSO 4 plus one electron. Lead dioxide, hydrogen ions and SO 4 ions, plus electrons from the lead plate create PbSO 4 and water on the lead dioxide plate. The characteristic voltage is about 2 volts per cell, so by combining six cells you get a 12-volt battery. If you apply current to the battery at the right voltage, lead and lead dioxide reform on the plates so you can reuse the battery over and over. In a zinc-carbon battery, there is no easy way to reverse the reaction because there is no easy way to get hydrogen gas back into the electrolyte.
Modern batteries use a variety of chemicals to power their reactions.
The electrodes are zinc and carbon, with an acidic paste between them that serves as the electrolyte. Alkaline battery - Used in common Duracell and Energizer batteries. The electrodes are zinc and manganese-oxide, with an alkaline electrolyte. The electrodes are made of lead and lead-oxide with a strong acidic electrolyte. Often used in hearing-aid batteries.