Dry cell batteries, regardless of their size, have the same components. At the center of each dry cell battery is a rod called a cathode, which is generally made of metal or graphite and is surrounded by an electrolyte paste. The cathode and electrolyte paste are wrapped in paper or cardboard. One or more of these cells are sealed into a metal cylinder called an anode, which is typically made of zinc or alkaline.
The anode in the dry cell battery has two or more terminals — one that is positive and one that is negative. When a load is connected to the battery's terminals, a chemical reaction occurs between the cathode and the paste in each cell to produce roughly 1.5 volts of electricity. A battery that has more than one cell will produce a higher overall voltage. After the load has been connected for a long time, the battery's chemicals can no longer react with each other and will therefore no longer produce a charge.
Alkaline batteries are more popular than their older zinc counterparts because they corrode more slowly and thus hold their charge longer. A less commonly used type of dry cell battery uses silver for the cathode rod. Another type is the mercury cell, which uses mercury in the cathode and is often used to power calculators. Nickel/cadmium (NiCd), nickel metal hydride (NiMH), and lithium-ion (Li-Ion) dry cell batteries are rechargeable, making them popular for use in power-hungry digital cameras and portable electronics.
All batteries contain chemicals that are harmful if released into the environment, so all used dry cell batteries should be recycled properly. Many municipal recycling programs accept batteries. Consumers should also consider using rechargeable batteries because they can be reused many times and can also be recycled after they no longer hold a charge.
