Batteries are systems that store chemical energy and then release it as electrical energy when they are connected to a circuit. Batteries can be made from many materials, but they all share three main components: a metal anode, a metal cathode and an electrolyte between them. The electrolyte is an ionic solution that allows charge to flow through the system. When a load, such as a light bulb, is connected, an oxidation-reduction reaction occurs that releases electrons from the anode while the cathode gains electrons
