## 1 Introduction
The electrolyte storage section possesses an anolyte and a catholyte contained in sealed containers, whereas the balance of the plant part basically consists of a recirculation loop and a battery management system. Concisely, vanadium electrolytes, which are V\({}^{2+}\) and VO\({}_{2}\)\({}^{+}\), are filled into storage tanks for the discharging process, and after the completed discharging process, the V\({}^{2+}\) and VO\({}_{2}\)\({}^{+}\) are converted to V\({}^{3+}\) and VO\({}^{2+}\), respectively [14]. The V\({}^{2+}\) and VO\({}_{2}\)\({}^{+}\) electrolytes can be prepared using alternative energy resources [15]. The electrolyte's concentration and quantity significantly influence the energy density and performance of VRFBs [16]. The relation between the electrolyte concentrations and a VRFB cell can be investigated via [PERSON]'s Equation (1):  
\[\mathrm{E_{cell}}=\mathrm{E_{cell}^{0}}-\frac{\mathrm{RT}}{\mathrm{F}}(\ln \frac{[\mathrm{VO_{2}}^{+}][\mathrm{V^{2+}}]}{[\mathrm{VO^{2+}}][\mathrm{V^{3 +}}]}) \tag{1}\]  
The parameters in the Equation can be defined as follows: \(\mathrm{E^{0}}\) is the formal of cell potential; \(\mathrm{R}\) is the universal gas constant (8.314472 J / mol K); \(\mathrm{T}\) is the temperature (K); \(\mathrm{F}\) is Faraday constant (96,485 C/mol); and [V] (M) represents concentrations of the different vanadium species in solution. Moreover, the electrolyte concentration affects energy efficiency, as illustrated in Equation (1). The energy efficiency can be calculated using Equation (2):  
\[\mathrm{\varepsilon_{energy}}=\mathrm{\varepsilon_{voltage}}\times\mathrm{ \varepsilon_{coulombic}} \tag{2}\]  
\(\mathrm{\varepsilon_{energy}}\) is energy efficiency, \(\mathrm{\varepsilon_{voltage}}\) is voltage efficiency, and \(\mathrm{\varepsilon_{coulombic}}\) is coulombic efficiency [17]. The prepared electrolyte solutions' physical and chemical properties represent critical factors for storing the active redox species carrying the electrical energy [14]. This work is interested in understanding the factors affecting electrolyte preparation for further development. A capable pathway to prepare vanadium electrolyte is to dissolve vanadyl sulfate (VOSO\({}_{4}\)) in sulfuric acid solution, since it promptly dissolves in aqueous solutions. Moreover, the prepared solution provides excellent stability [18]. It is worth noting that sulfuric acid is preferably considered as a suitable solvent; however, this solution system is restricted by the vanadium ion's solubility and stability. This restriction is mightily dependent on the temperature and concentration of the sulfuric acid [19]. A typical method entails increasing the current while measuring the voltage's evolution during charge and discharge cycles [20]. Plotting voltage vs. current to obtain a polarization curve is another method of analyzing VRFB performance. Accurate polarization characterization can be assessed using a technique that measures changes in cell voltage while the battery is functioning. The output current plays an important role in determining losses, namely, activation loss, ohmic loss, and concentration loss inside the VRFB, and the losses are influential factors to consider when comparing VRFB performance [21]. The polarization regions, which correspond to the losses, have been considered important parameters in several studies related to materials selection affecting the electrochemical reaction kinetics, internal resistance, mass transport in VRFB, and electrolyte diffusion through porous electrodes [21]. In addition to the importance of electrolyte preparation, voltage losses in VRFBs have to be reduced. It was found that material resistance principally generates losses. The actual voltage can be calculated from the difference between ideal voltage (E\({}^{0}\)) and voltage losses, including activation loss (\(\eta_{\text{act}}\)), ohmic loss (\(\eta_{\text{ohm}}\)), and mass transport loss (\(\eta_{\text{mass}}\)) [22].