Predicting operational capacity of redox flow battery using a generalized empirical correlation derived from dimensional analysis

Novel electrolyte rebalancing method for vanadium redox flow batteries

“…The formal oxidation state of this mixture lies ideally between these states and is often referred to as V 3.5+ [36]. Since VRFBs use the same electrolyte composition at the both positive and negative electrodes, they are not affected by cross contamination, which allows for long cycle life, but they suffer of performance degeneration and capacity loss, mainly due to electrolyte imbalance [37][38][39]. During simple charging operation, tetravalent vanadium VO 2+ is oxidized to pentavalent vanadium VO 2 + at the positive halfcell, while trivalent V 3+ is reduced to bivalent V 2+ at the negative one and vice versa during discharge.…”

Tactical Surface Modification of a 3D Graphite Felt as an Electrode of Vanadium Redox Flow Batteries with Enhanced Electrolyte Utilization and Fast Reaction Kinetics

“…Excellent utilization of vanadium species, also called electrolyte utilization (EU), allows high energy density and reduces electrolyte volume needed for practical use in the VRFB system, thus reducing the practical cost of the system. 3,5 The excellent value of the EU can be achieved by improving the electrochemical performance of carbonaceous electrodes for VO 2+ /VO 2 + and V 3+ /V 2+ redox couples in the VRFB system. 6,7 The electrochemical performance of carbonaceous electrodes mainly depends on their physicochemical properties, such as surface functionality, specific surface area, and surface wettability.…”

Recent progress on carbon and metal based electrocatalysts for vanadium redox flow battery

“…Vanadium redox flow battery (VRFB) is one of the electrochemical energy storage devices, which can store the energy very efficiently due to its decoupled energy and power capacity. VRFB systems have received great attention for large‐scale energy storage applications because of its long durability (~ up to 20,000 charge–discharge cycles), easy to scale the capacity, high response time as well as reliability, and low levelized cost (Kapoor et al, 2019). Structural arrangements of the components of a VRFB is depicted in Figure 1.…”

“…Macroscopically a VRFB single cell consists of an electrochemical cell and two electrolyte tanks (positive and negative electrolyte tank).In the electrochemical cell, two electrodes are separated by an ion‐exchange membrane and the positive and negative electrolyte tanks contains VO 2 + /VO 2+ and V 2+ /V 3+ redox couples, respectively dissolved in aqueous sulfuric acid solution. During charging and discharging, the electrolytes from the tanks are pumped and circulated through the cell, where vanadium species of the positive and negative electrolytes undergo redox reactions at electrodes (Equation (1) and (2); Kapoor et al, 2019). In principle, the energy capacity of the VRFB depends on the volume of electrolyte or concentration of vanadium species in electrolyte and the power of the VRFB depends on the electrode or number of cells in stack. …”

“…Several surface modifications or pretreatment methods such as Fenton's reagent treatment, electrochemical activations, thermal activation, acid, and thermal treatment and so on, have been highlighted till date (Gautam et al, 2020; Gautam & Verma, 2020; Kapoor et al, 2019; Wang et al, 2018; Zhang et al, 2013). Of these methods, introduction of an electrocatalyst on the surface of VRFB electrodes is one possible method to greatly improve the overall performance of VRFB by enhancing the kinetics of redox reactions and reduction of the overpotential losses and make it feasible to operate the VRFB at higher current densities (Park, Ryu, & Cho, 2015).…”