The two basic types of electrochemical cells are galvanic cells and electrolytic cells, according to UC Davis. Galvanic cells undergo spontaneous chemical reactions and release electrical energy, while electrolytic cells consume electricity to power non-spontaneous chemical reactions. Both types require an anode, a cathode, electrolyte solutions and a salt bridge.
Galvanic cells include devices such as non-rechargeable batteries. Such devices create a flow of electrons from one electrode to another, generally made from two different metals. In a galvanic cell, electrons flow from the anode to the cathode. During this process, the anode releases metal ions into a surrounding liquid or gel solution, the electrolyte. When the electrons flow to the cathode, they are taken up by the metal ions in the solution surrounding them, and the ions lose their charge and become standard metal atoms.
Rechargeable batteries act as electrolytic cells while they are being charged and galvanic cells when they are powering devices, according to UC Davis. An electrolytic cell uses electricity to force a chemical reaction to occur in the opposite direction it would spontaneously. Thus, the chemical reaction occurring in a recharging battery is the exact opposite of the reaction that occurs when the battery releases energy.