Aprile Coroneos, age 12, of Kansas City, Missouri, for her question:
What material is inside a battery cell?
Your house is wired to an immense electrical circuit that supplies power when needed. Battery cells make their own small helpings of electricity. They are not wired to the big circuit. You can carry them around and they are used for such jobs as starting cars and working flashlights.
There are many types of battery cell but all of them are made to give electrical power. For everyday jobs, we depend on the storage battery and the dry cell battery. A storage battery is kept inside an automobile to start the engine. It is a sizeable box, very sturdy and topped with a row of round knobs. You will find a dry cell battery inside a flashlight. It is a small, can shaped object, rather heavy for its size.
Batteries work because certain chemicals interact with each other. This chemical activity creates a special kind of energy that can be turned into electricity. The materials in a battery cell are chemicals, the special chemicals that work together to make electrical energy. As they interact, they change and use up their chemical energy. Then the battery is dead.
The first battery cell was made in the 1770s. It was a stack of metal saucers separated from each other by rags soaked in salty water. No one at the time knew why this group of chemicals created electricity. But the old trick still works and now we know why. 47e have made it stronger and more simple and improved it to invent a whole assortment of different batteries for different jobs.
The metal saucers used in the first battery were electrodes. The salty liquid was an electrolyte. Every battery must have two opposite electrodes, one with a positive charge and one with a negative. Every battery must have an electrolyte. And the chemical e1PCtrodes must be in contact with the chemical electrolyte. The role of each ingredient in a battery can be played by several different chemicals. Usually a storage battery has a positive electrode of carbon and a negative electrode of zinc. The two plates sit in a liquid electrolyte, most likely a weak solution of sulphuric acid.
The dry cell was invented 100 years ago. Its two electrodes are in contact with a paste electrolyte. Its negative electrode is the can shaped container, usually made of zinc. It is lined with papery material soaked in saI ammoniac and zinc chloride. The positive electrode is a carbon rod buried in the middle of the stuffing. The stuffing, of course, is the pasty electrolyte. It is most likely a mixture of sal ammoniac and zinc chloride, manganese oxide, carbon and graphite. These strange chemicals are powdered, mixed together and moistened with water.
A battery gets its go from acid chemicals. A normal atom, of course, has a definite number of orbiting electrons. This is true of the atoms in an acid. An acid usually dissolves in water and when this happens, its atoms tend to misplace some of their electrons. They become electrically charged ions, some with extra positive and some with extra negative charges. This chemical action produces the energy that a battery uses to deliver a helping of electricity.