Resource Dictionary

Cathode

The negatively charged electrode in an eletrolytic cell. In electrolytic refining of copper, anodes of impure blister copper and cathodes of pure copper are placed in an electrified solution of copper sulphate and sulphuric acid. Copper dissolves from the anode and is redeposited at the cathode, leaving behind impurities. The result is a rectangular plate of copper, usually 99.99% pure, referred to as a copper cathode or simply cathode.