All-vanadium liquid flow battery production

The membranes employed in vanadium flow batteries can be grouped into ion exchange membranes and physical separators; however, this topic will only focus on ion exchange membranes .

The cross-contamination of vanadium can cause self-discharge of the battery due to spontaneous disproportionation equilibria between V (V) and V (II) to produce V (III) or V (IV), V (V) and V (III) to produce V (IV), and V (IV) and V (II) to obtain (VIII) as described in Eqs. (4), (5), (6), (7).

A series of chemistries based on Zn, Fe, Cu, Br, Cr, Ru, or organic redox active compounds, the redox potentials fo which expand the voltage range of vanadium, have been studied in ILs to leverage the high electrochemical stability of ILs, .

Skyllas-Kazacos et al. developed the all-vanadium redox flow batteries (VRFBs) concept in the 1980s . Over the years, the team has conducted in-depth research and experiments on the reaction mechanism and electrode materials of VRFB, which contributed significantly to the development of VRFB going forward, , .

As an important branch of RFBs, all-vanadium RFBs (VRFBs) have become the most commercialized and technologically mature batteries among current RFBs due to their intrinsic safety, no pollution, high energy efficiency, excellent charge and discharge performance, long cycle life, and excellent capacity-power decoupling .

All-vanadium redox flow batteries use V (II), V (III), V (IV), and V (V) species in acidic media. This formulation was pioneered in the late eighties by the research group of Dr Maria Skyllas-Kazacos as an alternative to the Fe/Cr chemistry originally proposed by NASA.