Batteries

A battery is a galvanic cell or (more commonly) a group of galvanic cells connected in series, where the potentials of the individual cells add to give the total battery potential.'
The lead storage battery can function for several years under temperature extremes.  In this battery, lead serves as the anode and lead coated with lead dioxide serves as the cathode.  Both electrodes dip into an electrolyte solution of sulfuric acid.  The reactions are:

Anode:                                     Pb + HSO4-  ---->   PbSO4 + H+  +  2e-
Cathode:     PbSO4 + HSO4- + 3H+  +  2e-  ---->  PbSO4 + 2H20

Because sulfuric acid is consumed as the battery discharges, the condition of the battery can be monitored by measuring the density of the sulfuric acid solution.  A car with a dead battery can be jump-started by connecting its battery to the battery in a running automobile.
Also, traditional types of storage batteries require periodic "topping off" because the water in the electrolyte solution is depleted by the electrolysis that accompanies the charging process.
Another common battery is the dry cell battery which has an acid version and an alkaline version.  In the acid version, the battery contains a zinc inner case that acts as the anode and a carbon rod in contact with a paste of solid MnO2, solid NH4Cl, and carbon that acts as the cathode.  In the alkaline version of the battery, the solid NH4Cl is replaced with KOH or NaOH.  The alkaline version lasts longer because the zinc anode corrodes less rapidly under basic conditions than acidic conditions.
There are also silver cells (has a Zn anode and a cathode with Ag2O as the oxidizing agent), mercury cells (Zn anode and a cathode with HgO as the oxidizing agent).
A fuel cell is a galvanic cell for which the reactants are continuously supplied.