Technical analysis of all-vanadium liquid flow batteries

In the field of electrodes, vanadium battery electrodes mainly include carbon electrodes, metal electrodes and composite electrodes. The carbon electrode has the characteristics of strong stability, corrosion resistance, good electrical conductivity, low cost, etc., but the electrochemical activity is poor, to be further improved.

Metal electrodes have the advantages of good conductivity, high mechanical properties, high electrochemical activity, etc., but the discharge process is easy to form a passivation film, which seriously affects the reaction.

Composite electrodes are generally made of polymer and carbon materials mixed with processing and moulding, with low internal resistance, good electrochemical stability, high conductivity and other advantages.

In the diaphragm, the most widely used cation exchange membrane for the Nafion membrane, the membrane voltage efficiency of more than 90%, good conductivity, increase the thickness of the membrane, can effectively improve battery efficiency, but the cost will increase.

Anion exchange membrane in vanadium batteries through the membrane electrolysis anions and electrolysis in the anionic cross, such as sulfate ions, to complete the transmission of carriers.

In addition, amphoteric ion exchange membrane is one of the current research hotspots, which has the characteristics of cation and anion exchange membrane.