A simple-yet-elegant device, the modern alkaline battery has only a few main components. The difference in electron affinity between zinc (Zn) and manganese dioxide (MnO2) drives its basic reaction. Because the manganese dioxide has a greater attracting power for electrons, it creates a potential for electrical current.
The container is a standardized shape steel construct that holds the entire battery together. The cathode is part of the container, molded just inside it.
The cathode is the part of the battery that will attract electrons if the circuit is closed, thereby causing electricity to flow. In an alkaline battery, the cathode is made of manganese dioxide mixed with carbon (graphite). This material is put in the container first. The cathode will become the positive (+) terminal on top of the battery.
This material separates the anode from the cathode and keeps the reaction from occurring, unless the powered device is on and the circuit is thereby closed. This material is inserted after the cathode is installed.
The anode material is made of powdered zinc. The anode, electrolyte, and collector are installed in the battery container last, and then the battery is sealed.
In an alkaline battery, the electrolyte is potassium hydroxide (KOH) in a solution of water. It is in contact with the anode material and helps ions and electrons flow.
This is a brass pin in the center of the anode that collects current and leads to the negative (-) terminal on the bottom of the battery.
- Image by Flickr.com, courtesy of Windell Oskay