Battery Types & Chemistries

Battery is a vessel containing various chemicals which produces electricity as a result of reactions taking place between these chemicals. These reactions which produce electrons are called electrochemical reactions. The earliest version of the battery was created by Alessandro Volta. He used alternating layers of Zinc, blotting paper soaked in salt water and Silver, known as a voltaic pile.

Here is an explanation of the chemical reaction taking place in a simple form of Zinc-Carbon battery. A small jar containing Sulphuric Acid (electrolytesolution), a Zinc rod and a Carbon rod (electrodes) are required. When both the rods are placed in the acid, an immediate noticable reaction takes place. The Zinc in the anode (the negative terminal) oxidizes, releasing negatively charged electrons and positively charged metal ions. The electrons travel through the wire (and the electrical load) to the cathode, Carbon (the positive terminal). The electrons combine with the Hydrogen ions at the cathode, releasing Hydrogen gas bubbles. While the Zinc rod dissolves to form Zinc sulphate.

However, this would be impractical as a battery with a highly corrosive liquid in a container and outlet for the gas produced. The Zinc/Carbon batteries which are commonly known as standard battery contains an acidic paste which serves as the electrolyte. Allowing for a more compact size that we use today. Modern batteries use different chemicals, listed below are some of the widely used battery chemistries. These can be grouped into two fundamental types, primary and scondary. Primary cells are meant meant to be used once only and Secondary cells are designed to be recharged over and over (typically several hundreds of times). Energizer's Learning Center have useful information on how batteries work, history and how these are constructed.