For better characterization of the vanadium electrolyte, INO-HUB purchased a TitroLine® 7000 titrator with a combined metal electrode with a platinum membrane Pt 62. It allows determining the concentration of vanadium in the oxidation state V3+ and the total concentration of vanadium in the electrolyte solution by potentiometric titration.
Potentiometric titration is based on measuring the potential difference in mV between the indicator (working) and reference electrodes, which are immersed in the solution. The titration reagent – potassium permanganate (KMnO4) solution is added in small volumes. The electromagnetic stirrer ensures mixing of the titrated solution throughout the titration period. After each addition of a certain volume of titration reagent and stabilization of the potential of the titrated solution, the consumption of the titration reagent is recorded, which corresponds to the change in potential. The highest value of the potential difference is at the equivalence point. The titration curve is a graphical representation of the dependence of the change in potential on the volume of reagent.
During titration, the oxidation of V3+ to V4+ occurs. The first equivalence point on the titration curve corresponds to the concentration of V3+ and the second equivalence point to the total concentration of vanadium in the electrolyte solution. From the titration curve, it is possible to evaluate the electrolyte balance and verify the presence of sufficient V3+ in the solution at the beginning of the titration.
The TitroLine® 7000 titrator from SI Analytics allows titration to be performed in a short time and provides many functions such as direct conversion using by calculation formula to the concentration of vanadium V3+ in a sample of electrolyte. In addition, the titration progress can be viewed on the display and the results can be saved to a USB flash drive. One of the biggest advantages is the possibility of replacing the titration unit with reagent, which offers the possibility of further measurements in order to obtain more parameters about the electrolyte solution sample.
ACKNOWLEDGEMENT:
This work was supported by the project: IPCEI_IE_FLOW_BESS_012021_2. phase
Referencies:
1. https://web2.mendelu.cz/af_291_projekty2/vseo/files/145/9991.pdf
2. https://www.xylemanalytics.com/en/general-product/id-23/si-analytics-titrator-titroline%C2%AE-7000-automatic-titrator-with-exchangeable-head
