In this article, we review the vanadium-based technology for redox flow batteries (RFBs) and highlight its strengths and weaknesses, outlining the research that aims to make it a commercial success.
What is a vanadium flow battery?
Vanadium Flow Batteries (VFBs) are a stationary energy storage technology, that can play a pivotal role in the integration of renewable sources into the electrical grid, thanks to unique advantages like power and energy independent sizing, no risk of explosion or fire and extremely long operating life.
Does reprocessed vanadium electrolyte reduce emissions?
The influence of the foundation is marginal compared to the electrolyte. In the 10 considered impact indicators, this leads to a reduction of emission between 0.97% (ODP) and 91.8% (AP). On average, a VFB using reprocessed vanadium electrolyte instead of primary electrolyte has only 53% of potential environmental impacts.
Where can vanadium be sold?
Alternatively, vanadium can be sold to the iron and steel industry which sums up 80% of the whole vanadium demand, in a market trend where the production of vanadium is constantly increasing, from 35,000 t in 1994 to almost 90,000 t in 2020 .
It is widely anticipated that the vanadium electrolyte may be reused in several life cycles. Thus, a fair allocation of the primary electrolyte's emissions over the life cycles is desirable. In this work, emissions of primary vanadium electrolyte are equally divided over the primary and subsequent reuse life cycles.
The testing procedure presented in Ref. can constitute a standard approach for the performance assessment of kW-class VFBs, which at present is lacking, and can contribute to the definition of performance parameters for the comparison of different All-vanadium redox flow batteries .
Does CL - improve the redox activity of the vanadium ion redox reaction?
It is found that Cl - can improve the activity of the vanadium ion redox reaction and reduce the charge transfer resistance. The VRFBs with 0.04 M Cl - in the electrolytes have an electrolyte utilization and EE of 86.3 % and 82.5 % at 200 mA cm −2, respectively, and even at 400 mA cm −2, the EE remains at 70 %.