Galvanic cell bridge zinc ions leave and anions enter the zinc half-cell. In the copper half-cell, the copper ions plate onto the copper electrode (reduction), taking up electrons that leave the external conductor. Since the Cu ions (cations) plate onto the copper electrode, the latter is called the cathode. Correspondingly the zinc electrode is the anode. The electrochemical reaction is: In addition, electrons flow through the external conductor, which is the primary application of the galvanic cell. As discussed under #Cell voltage, the emf of the cell is the difference of the half-cell potentials, a measure of the relative ease of dissolution
Vanadium redox battery cell electrochemistry within the electrode is poorly known. Electrolytic wetting of carbon electrodes in VRFBs is important for overcoming sources of degradation and applying appropriate operational procedures. Recently, it appears that electrolytic wetting behaviour within the electrode may be influenced by local concentration effects as well as capillary action. Rapid wetting or permeation may also leave behind undissolved gases which could cause electrode degradation. The extremely large capacities possible from vanadium redox batteries make them well suited to use in large power storage applications such as helping to average out the production of highly variable generation sources such as wind