What is the half cell?
A half cell is one of the two electrodes in a galvanic cell or simple battery. For example, in the Zn-Cu battery, the two half cells make an oxidizing-reducing couple. Placing a piece of reactant in an electrolyte solution makes a half cell.
Standard Electrode Potentials. In an electrochemical cell, an electric potential is created between two dissimilar metals. This potential is a measure of the energy per unit charge which is available from the oxidation/reduction reactions to drive the reaction.
- The electromotive force (e) or e.m.f. is the energy provided by a cell or battery per coulomb of charge passing through it, it is measured in volts (V). It is equal to the potential difference across the terminals of the cell when no current is flowing.
- The direction of electron flow in electrolytic cells, however, may be reversed from the direction of spontaneous electron flow in galvanic cells, but the definition of both cathode and anode remain the same, where reduction takes place at the cathode and oxidation occurs at the anode.
- In battery technology, a concentration cell is a limited form of a galvanic cell that has two equivalent half-cells of the same composition differing only in concentrations. Concentration cell corrosion occurs when two or more areas of a metal surface are in contact with different concentrations of the same solution.
Updated: 25th November 2019