Electrode reaction cannot be reversed, and the identities of the anode and cathode are therefore fixed. The anode is always the negative electrode. 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. This is also the case in an electrolytic cell. When the cell is being discharged, it behaves like a primary cell, with the anode as the negative and the cathode as the positive
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