Preparation of electrolyte from recycled V2O5 for vanadium redox flow batteries and evaluation of its application potential

With the development of the world and the improvement of living standards, the demand for energy is increasing. To meet this demand and minimize environmental threats, it is essential to utilize renewable energy sources. However, one of the key challenges in renewable energy is the lack of stable energy supply. Consequently, there is a growing need for high-capacity energy storage systems. Vanadium redox flow batteries (VRFB) are considered a promising technology for storing energy from renewable sources. However, the widespread adoption of VRFBs is limited by several factors, including the high cost of electrolytes, which accounts for 30 – 40 % of the total battery cost. One of the main reasons for this is the use of high-purity vanadium oxide (V2O5). An alternative solution could be the use of less pure or recycled V2O5 for electrolyte production, which would reduce costs and enhance the environmental efficiency of the technology. Despite the large number of studies on electrolytes for vanadium batteries, research on the use of recycled V2O5 is scarce. This article investigates the possibility of using recycled V2O5 for electrolyte preparation. A laboratory prototype of a single-cell membrane electrochemical block was fabricated for testing. The change in the oxidation state of the electrolyte during charge-discharge cycles was studied using a UV-1280 spectrophotometer. Optimal current density parameters were determined for various operating modes. A total of 300 charge-discharge cycles were conducted, demonstrating the stability, energy efficiency, and charge capacity of the electrolyte.