Alkaline battery
An alkaline battery is usually a primary cell (it cannot be recharged), but some are rechargeable. It is very common. Duracell, Rayovac, and Energizer are common brands of alkaline batteries. They were introduced in the 1960s and replaced the Leclanche battery as the "everyday battery" in the 1990s. They are marketed in many forms, such as AAA, AA, C, D, 9V, and small disc cells for watches and calculators. In the battery, zinc is oxidized by manganese dioxide in a potassium hydroxide electrolyte.
Alkaline Battery Media
Thomas Edison's nickel–iron batteries manufactured under the "Exide" brand, originally developed in 1901 by Thomas Edison used a potassium hydroxide electrolyte.
Several sizes of button and coin cells. Some are alkaline and others are silver oxide. Two 9 V batteries were added as a size comparison. Enlarge to see the size code markings.