Alkaline batteries, or alkaline manganese batteries, are commonly used in many things such as flashlights and personal stereos. They serve as excellent sources of energy for these things. They are examples of one of three major dry primary batteries, which are carbon-zinc, alkaline and mercury cells. A cell is the basic electrochemical unit used to generate or store electrical energy. A battery contains two structures called electrodes. Primary batteries stop operating after one of their chemicals is used up. An electrode is the site, area or location at which electrochemical processes take place. The two electrodes of the alkaline battery are zinc and manganese dioxide. Zinc is the anode, or the electrode that becomes negatively charged due to the electrolyte. Manganese dioxide is the cathode, or the electrode that becomes positively charged. An electrolyte is the medium that provides the ion transport mechanism between the anode and cathode of a cell. The electrolyte of an alkaline cell is a strong alkali solution called potassium hydroxide. Under high current loads, the alkaline battery has a steady voltage of about 1.5 volts. Voltage, or potential difference is defined as the difference in electric potential between two points.
The alkaline battery has a higher energy output than that of carbon-zinc cells. It also has better leakage resistance, the resistance calculated from the dependence of leakage current on applied voltage. Leakage current is unwanted current that flows when test voltage is applied. The alkaline battery can be either primary or secondary (also called storage). Unlike the alkaline primary battery, the alkaline storage battery is rechargeable and can be used again after discharge of its electric energy. The alkaline, nickel-iron storage battery was developed in 1914 by Thomas Alva Edison. The alkaline storage battery contains an alkaline, or basic electrolyte, which can be easily transported.
