What is the process of using electricity to decompose a compound called?

The process of using electricity to decompose a compound is called electrolysis.

Electrolysis uses direct electric current to drive a chemical reaction that would not normally occur spontaneously. The setup requires an electrolyte, which contains mobile ions, two electrodes, and an external power source. Positive ions move toward the negative cathode, where reduction occurs; negative ions move toward the positive anode, where oxidation occurs.

One familiar example is the electrolysis of water. Under suitable conditions, electricity separates water into hydrogen and oxygen, with hydrogen forming at the cathode and oxygen at the anode. Industrial electrolysis is also used for metal extraction, electroplating, refining, and producing chemicals such as chlorine and sodium hydroxide from brine.

The word comes from Greek roots meaning electricity and loosening or splitting. Michael Faraday introduced the term in 1834 and formulated two laws connecting the amount of chemical change with the quantity of electricity passed through an electrolytic cell. Electrolysis is often confused with photolysis, which uses light, or pyrolysis, which uses heat; hydrolysis uses water as a reactant rather than an electrical current.