Production

WELDING ELECTRODES

An electrode in an electrochemical cell is referred to as either an anode or a cathode (words that were coined by William Whewell at Faraday's request).[1] The anode is now defined as the electrode at which electrons leave the cell and oxidation occurs, and the cathode as the electrode at which electrons enter the cell and reduction occurs.

A primary cell is a special type of electrochemical cell in which the reaction cannot be reversed, and the identities of the anode and cathode are therefore fixed. The cell can be discharged but not recharged.

A secondary cell, for example a rechargeable battery, is a cell in which the chemical reactions are reversible. When the cell is being charged, the anode becomes the positive (+) and the cathode the negative (−) electrode.