Dear Shereen and Jasmine,

Batteries can power up all kinds of gadgets. To find out how batteries work, I decided to visit my friend and materials engineer Min-Kyu Song. He makes batteries in his lab at Washington State University.

As you might know, materials are made up of atoms—and atoms have tiny parts called electrons. If you’ve ever felt a spark when you touched a doorknob, you’ve felt electrons making the jump between your body and the door.

Inside a battery

If you look at a battery, perhaps the kind you’d find in a television remote, you might see a little negative sign (-) on one end. That end of the battery is called an anode. Song explains that an anode can be made up of different metals.

illustrated cartoon gray cat, Dr. Universe, wearing a white lab coat, yellow pants, and a crimson shirt with Washington State University logoIn a battery, an anode is usually made up of a material that contains a lot of energetic electrons, like the zinc in a AA battery. An anode is on a mission to give some of its electrons away.

At the opposite end of the battery is a part that wants to take some of those electrons. It is marked with a plus sign (+) and called a cathode.

Cathodes can also be made of different materials, such as manganese oxide. But these materials don’t contain as many energetic electrons as the metal that makes up our anode.

Charging things up

The third part of the battery is a liquid or solid mixture of chemicals called an electrolyte. The electrolyte contains some electrically charged particles called ions. You actually have electrolytes in your blood. We can also find them in sports drinks.

If a battery just sits on the counter, even if it has all of these three parts, you may notice it doesn’t do much. That’s because the electrolyte, which can sometimes be an acidic salt solution, blocks any electrons from moving around inside the battery.

It isn’t until we attach a wire, like copper, to each end of the battery, that a chemical and electrical, reaction will start. Electrons will start flowing.

You might think of it as an endless, cycling waterfall—the many electrons from the anode start flowing down the wire to the cathode that takes them all in, then some of the ions carry the charges through the electrolyte, back to the anode, and up the wire again. We can also add parts like a lightbulb or a motor along the wire to make them work. When the chemical reaction is over, we eventually end up with a dead battery.

Building new batteries

In Song’s lab, engineers experiment with different materials to help invent new, more powerful batteries. They are also looking for ways to keep some batteries from burning up, creating even safer batteries for us to use in the future.

Just imagine, without batteries we’d have to plug in all our electronics with wires and cords. Cats everywhere might be entertained, but it would probably become a big tangled mess. Batteries help us store energy in the form of chemicals so we can use all kinds of gadgets.

Dr. Universe