Electrolytic cell

[1]: 89 [3][page needed] This is in contrast to a galvanic cell, which itself is a source of electrical energy and the foundation of a battery.

In a galvanic cell, the progress of a spontaneous chemical reaction causes an electric current to flow.

Only with an external electrical potential (i.e., voltage) of correct polarity and sufficient magnitude can an electrolytic cell decompose a normally stable, or inert chemical compound in the solution.

To an external wire connected to the electrodes of a galvanic cell (or battery), forming an electric circuit, the cathode is positive and the anode is negative.

Thus positive electric current flows from the cathode to the anode through the external circuit in the case of a galvanic cell.

Important examples of electrolysis are the decomposition of water into hydrogen and oxygen, and bauxite into aluminum and other chemicals.