Dry Cell Battery

The battery in its original form had a zinc rod amalgamated with mercury as anode, a conducting mix of manganese dioxide (MnO2) and Carbon in porous pot as cathode, a central carbon rod or plate as current collector, and a saturated solution of ammonium chloride (NH4Cl) as electrolyte. The cell was assembled in a glass jar and produced about 1.5 volts. In spite of its lack of portability, it was widely used in telephones and doorbells until well into the 20th century and was an excellent example of a technical advance that became an immediate commercial success.

The modern dry cell replaced the liquid replace the liquid electrolyte with a paste consisting of a mixture of zinc chloride (ZnCl2) and NH4Cl. A zinc anode was fashioned as a cylindrical cell container, and the cathode remained MnO2 and Carbon.

Storage Battery
For many years in standard secondary (storage) system has been the lead-acid battery. Nickel-cadmium batteries have also become common. In recent years other type have been developed that are applicable to specialized demands. The lead-acid battery was invented in 1860 by Gaston Plante. The electrolyte is sulfuric acid (H2SO4), the electrode are lead and lead dioxide (PbO2). Three or six cells are placed within a plastic or rubber container, the form seen in automobiles. Recently, small D-size batteries of this type have been introduced.