A zinc-carbon battery is a dry cell primary battery that delivers about 1.5V of DC from the electrochemical reaction between Zn (Zinc) and MnO2. A carbon rod collects the current from the MnO2 (manganese(iv)oxide) electrode, as its name implies.
A dry cell is usually made from zinc, which serves as the anode with a negative electrical polarity, while the inert carbon rod serves as the positive electrical pole cathode. These batteries made portable devices such as the flashlight possible because of its ability to function in a diverse set of these devices besides the fact that they were the first set of commercial dry batteries. Its formation can be seen below:
Zn + 2 Cl− → ZnCl2 + 2 e−
2 MnO2 + 2 NH4Cl + H2O + 2 e– → Mn2O3 + 2 NH4OH + 2 Cl−
Zn + 2 MnO2 + 2 NH4Cl + H2O → ZnCl2 + Mn2O3 + 2 NH4O
Zn + 2 Cl− → ZnCl2 + 2 e−
2 MnO2 + ZnCl2 + H2O + 2 e− → Mn2O3 + Zn(OH)2 + 2 Cl−
Zn + 2 MnO2 + H2O → Mn2O3 + Zn(OH)2
The zinc-carbon battery is to be stored at room temperature as recommended by manufacturers. Storing them at a temperature higher than the recommended temperature would thwart, terminate and, shorten the shelf life of the battery. It is safe to store it below room temperature, that is, freezing, but before use, it must be unfrozen to enable it to function effectively and prolong its shelf life.
The zinc-carbon cells have a short shelf life laying the fact that the zinc is constantly attacked by ammonium chloride. And as it is being used it becomes thinner and thinner until its no longer functional for use.
