Cell architecture upswing based on catalyst coated membrane (CCM) for vanadium flow battery

To promote the practical application of electro-catalyst in vanadium flow battery, cell architecture based on catalyst coated membrane (CCM) is designed. CCM is prepared via spraying electro-catalyst tungsten trioxide/super activated carbon, which exhibits excellent electrochemical performance toward vanadium redox couples, on both sides of the membrane. Results show that the use of CCM structure reduces the charge transfer impedance of the cell, and thus improves the energy efficiency and the power density remarkably. The voltage efficiency and energy efficiency reach as high as 85.9% and 81.2%, respectively, much higher than that using the traditional cell structure (81.3% and 76.9%) at 120 mA cm−2. No loss in efficiency after 300 cycles indicates the favorable cycle stability of CCM. Therefore, CCM can be used as a promising vanadium flow battery structure for enhanced efficiency and power density.

► Power density of VFB is evidently improved by CCM architecture upswing. ► The energy efficiency of VFB reaches as high as 81.2% at 120 mA cm−2 ► The cell assembled with CCM exhibits excellent long-term cycle stability. ► CCM provides an effective way for electro-catalyst practical application in VFB.