Vanadium Electrolyte Research Articles

A Review of Electrolyte Additives in Vanadium Redox Flow Batteries.

Vanadium redox flow batteries (VRFBs) are promising candidates for large-scale energy storage, and the electrolyte plays a critical role in chemical-electrical energy conversion. However, the operating temperature of VRFBs is limited to 10-40 °C because of the stability of the electrolyte. To overcome this, various chemical species are added, but the progress and mechanism have not been summarized and discussed yet. This review summarizes research progress on electrolyte additives that are used for different purposes or systems in the operation of VRFBs, including stabilizing agents (SAs) and electrochemical mass transfer enhancers (EMTEs). Additives in vanadium electrolytes that exhibit microscopic stabilizing mechanisms and electrochemical enhancing mechanisms, including complexation, electrostatic repulsion, growth inhibition, and modifying electrodes, are also discussed, including inorganic, organic, and complex. In the end, the prospects and challenges associated with the side effects of additives in VRFBs are presented, aiming to provide a theoretical and comprehensive reference for researchers to design a higher-performance electrolyte for VRFBs.

Cost-effective electrodes based on mixed iridium-zirconium oxides for vanadium electrolyte rebalancing cell

Developing the mixed metal oxide (MMO) electrodes with high electrocatalytic activity, low cost of materials and long service life is an important and relevant task for various applications including the vanadium electrolyte rebalancing. In this work, the cost-effective electrodes based on mixed iridium-zirconium oxides were fabricated using the Pechini method followed by thermal decomposition. The Raman and XPS analysis of mixed IrO2–ZrO2 electrodes showed a partially crystalline (IrO2 and ZrO2) and partially amorphous (IrOx and ZrOx) structure. Conducted electrochemical tests demonstrated the high electrocatalytic performance of the electrodes with 15–30 mol% of Zr addition comparable to Ir-based electrodes toward the OER. Successful proceeding of the electrochemical reduction in the rebalancing cell was proved using operando absorbance spectra analysis of the reducing vanadium electrolyte. The results of a prolonged vanadium electrolyte electroreduction showed more effective performance of the cell with 70Ir–30Zr electrode than the same cell with 70Ir electrode under a high current density of 250 mA cm−2. This approach allows reducing the electrode cost with reducing the Ir loading without sacrificing the electrocatalytic properties with Zr adding.

A mediated vanadium flow battery: Lignin as redox-targeting active material in the vanadium catholyte

Vanadium Redox Flow Batteries (VRFB) are promising candidates for stationary energy storage but show certain drawbacks at low energy densities (<30 Wh L−1) and a narrow operating temperature range (15–40 °C). The latter is mainly caused by the limited stability of the catholyte at elevated temperatures. Therefore, in this work we introduce a stability enhanced vanadium catholyte with redox mediating properties conferred by the highly abundant organic polymer lignin to achieve higher performance in temperature range for a penetration of the VRFB systems in thermal applications. By reducing the vanadium concentration to 0.9 M the catholyte's stability is significantly improved so that a wider operational temperature window for the flow cell can be exploited. To compensate the loss in energy density lignin as a solid capacity booster is added to the positive reservoir. Herein, the feasibility of lignin in combination with multiwalled carbon nanotubes as solid charge storage material is investigated by cyclic voltammetry and charge/discharge cycles at temperatures from 10 °C to 45 °C. Volumetric capacities >28 Ah L−1 are achieved for the capacity-boosted VRFB with 0.9 M catholyte that are comparable with the conventional 1.8 M vanadium electrolyte. The use of an abundant renewable resource like lignin in the VRFB could not only increase cell performance but also attribute to lower the high operational costs and environmental impact of the battery.

A Flexible Six-in-One Microsensor Embedded in a Vanadium Redox Flow Battery for Long-Term Monitoring.

The vanadium redox flow battery (VRFB) can be used as a supporting technology for energy storage corresponding to wind and solar power generation. An aqueous vanadium compound solution can be used repeatedly. As the monomer is large, the flow uniformity of electrolytes in the battery is better, the service life is long, and the safety is better. Hence, large-scale electrical energy storage can be achieved. The instability and discontinuity of renewable energy can then be solved. If the VRFB precipitates in the channel, there will be a strong impact on the flow of vanadium electrolyte, and the channel could even be blocked as a result. The factors which influence its performance and life include electrical conductivity, voltage, current, temperature, electrolyte flow, and channel pressure. This study used micro-electro-mechanical systems (MEMS) technology to develop a flexible six-in-one microsensor which can be embedded in the VRFB for microscopic monitoring. The microsensor can perform real-time and simultaneous long-term monitoring of the physical parameters of VRFB, such as electrical conductivity, temperature, voltage, current, flow, and pressure to keep the VRFB system in the best operating condition.

Preparation of vanadium electrolyte from vanadium shale leaching solution with high concentration chloride using D2EHPA

A process for preparing vanadium electrolyte accompanied by the recovery of valuable elements from vanadium shale was proposed. The results showed that under the optimal extraction conditions of the feed solution at a pH of 2.6, D2EHPA concentration of 20%, phase ratio (O/A) of 1:1, extraction time of 8 min, H2SO4 concentration of 4 mol/L, and stripping time of 30 min, the vanadium extraction rate was 99.3% and the vanadium stripping rate was 99.8%. The composition and electrochemical performance of the electrolyte were studied in detail. The solution chemical and FTIR analysis showed that chloride ions in the leaching solution formed complexes with vanadium ions, promoting vanadium extraction. The proposed method in this study realized the comprehensive utilization of vanadium shale and prevented toxic environmental pollution in the preparation process of vanadium electrolyte.

Removal of Fe Impurity Ions from a Spent Vanadium Electrolyte Using Capacitive Deionization Based on Resin/Activated Carbon Composite Electrodes

Capacitive deionization (CDI) based on LSC-957 resin/carbon composite electrodes was used to remove Fe impurity ions from a spent vanadium electrolyte, which enabled simple and efficient regeneration of the electrolyte. The experiments conducted in this study demonstrated that 3:1 was the optimal mass ratio of LSC-957 resin to activated carbon for the preparation of the composite electrodes, and the optimal operating voltage and operating time were 0.9 V and 6 h, respectively. After five stages of CDI tandem treatment, the adsorption rate of Fe impurity ions was 86.84% and the loss rate of V was only 3.8%. The energy efficiency of the regenerated electrolyte was 84.49%, and its performance was significantly improved compared to the spent vanadium electrolyte. The adsorption process of composite electrodes was analyzed by kinetic and isothermal models’ fit, SEM-EDS, and FTIR. This work has provided an effective and novel method for removing impurity ions from a spent electrolyte.

A Bifunctional Liquid Fuel Cell Coupling Power Generation and V3.5+ Electrolytes Production for All Vanadium Flow Batteries.

All vanadium flow batteries (VFBs) are considered one of the most promising large-scale energy storage technology, but restricts by the high manufacturing cost of V3.5+ electrolytes using the current electrolysis method. Here, a bifunctional liquid fuel cell is designed and proposed to produce V3.5+ electrolytes and generate power energy by using formic acid as fuels and V4+ as oxidants. Compared with the traditional electrolysis method, this method not only does not consume additional electric energy, but also can output electric energy. Therefore, the process cost of producing V3.5+ electrolytes is reduced by 16.3%. This fuel cell has a maximum power of 0.276mW cm-2 at an operating current of 1.75mA cm-2 . Ultraviolet-visible spectrum and potentiometric titration identify the oxidation state of prepared vanadium electrolytes is 3.48 ± 0.06, close to the ideal 3.5. VFBs with prepared V3.5+ electrolytes deliver similar energy conversion efficiency and superior capacity retention to that with commercial V3.5+ electrolytes. This work proposes a simple and practical strategy to prepare V3.5+ electrolytes.

Electrochemical activity of tungsten oxide doped carbon (WO3/C) catalyst for hydroquinone/benzoquinone redox flow battery

The research in organic flow batteries is emerging as the cost of the vanadium electrolyte limits the grid-scale application. Tungsten trioxide doped carbon (WO3/C) electrocatalyst is developed to examine its potential in hydroquinone - benzoquinone redox flow battery (HQ/BQ RFB). The catalyst is characterized by a field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), and fourier transform infrared spectroscopy (FTIR) and confirms the formation of active WO3/C electrocatalyst. The electrochemical activity of the synthesized WO3/C electrocatalyst is inspected by cyclic voltammetry (CV). It shows comparatively high anodic and cathodic peak currents, low charge transfer resistance, and relatively high electrokinetic reversibility. The charge–discharge test on single cell HQ/BQ RFB is conducted using pristine carbon paper (CP), and WO3/C coated carbon paper (WO3/C-CP). The columbic efficiency (CE), voltage efficiency (VE), and energy efficiency (EE) of the RFB using WO3/C-CP are around 90%, 75%, and 70%, respectively, which are significantly higher than the CP. The improvement in results demonstrates that the WO3/C electrocatalyst is better at providing active sites and improving the electrochemical reactions kinetics, thus suits the application of HQ/BQ RFB.

Conducting polymer/transition metal carbide nanocomposite treated graphite felt as positive electrode in all-vanadium redox flow battery

Vanadium redox flow battery (VRFB) has been attractive and created attention in energy storage technology. In this study, graphite felt (GF) coated with conducting polymer/transition metal carbide nanocomposite (NPTiC) used to examine the electrochemical behavior for battery applications. Chemical oxidation has been employed to create the polyaniline (PANI) powder. Through a Mechano-chemical technique, nano-Titanium Carbide (NTiC) and nanocomposites (PANI with various proportions of 2 %, 4 %, 6 %, 8 % and 10 % of TiC) were created. XRD, FTIR, SEM, TEM and TGA are used to characterize them. Studies of electrochemical performance such as Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS) were carried out for PANI, NTiC and all nanocomposites. The results revealed excellent reversibility of an electron transfer and low impedance between the electrode and vanadium electrolyte compared to PANI and NTiC. Utilizing a 132 cm2 electrode, the study of charge-discharge for PANI, NTiC and NPTiC6 nanocomposite materials treated on GF (named as PANI/GF, NTiC/GF and NPTiC6/GF) as a positive electrode and untreated graphite felt (UTGF) retained as a negative electrode was done using a vanadium electrolyte and Nafion 117 membrane. The best performance is at 30 mA/cm2 current density and showed enhancements in coulombic efficiency (ղC), voltaic efficiency (ղV) and energy efficiency (ղE) than PANI and NTiC electrodes on GF. High Coulombic efficiency of 98.89 % was calculated for the NPTiC6/GF electrode. Even after 50 cycles, there was only 12 % coulombic efficiency decay, confirming the nanocomposite electrode's stability. The findings suggest that the electrochemical performance of the NPTiC6 nanocomposite is excellent.

Clean and cost-efficient preparation of vanadium electrolyte from the vanadium-rich solution of black shale by solvent extraction

This study proposes a clean and cost-efficient preparation process for vanadium electrolytes from the vanadium-rich solution of black shale. The introduction of saponified D2EHPA promoted vanadium recovery and further separation of impurities from vanadium-rich solutions. The preparation of a high-purity vanadium electrolyte was achieved by a four-stage countercurrent extraction at an initial pH as low as 1.0, 8 min, D2EHPA concentration of 30%, saponification degree of 60%, and phase ratio of 1:1, as well as a three-stage countercurrent stripping with 4 mol L−1 H2SO4 at phase ratio (O/A) of 6:1, 30 min. The developed electrolyte showed qualified electrochemical and charge-discharge performance, with coulombic efficiency, voltage efficiency, and energy efficiency reaching 91.07%, 93.44%, and 85.10%, respectively. This method saves 30.28% in preparation costs over the traditional method and produces no ammonia, nitrogen, or harmful gases. The technology is technologically advanced, economically sensible, and ecologically friendly, and is expected to be applied to large-scale production and promote the development of VRFB and new energy.

Self-Discharging and Corrosion Problems in Vanadium Redox Flow Battery

Vanadium redox flow battery (VRFB) has a potential for large energy storage system due to its independence of energy capacity and power generation. VRFB is known to have challenges of high price, corrosion problem and lower energy efficiency. In this work, VRFB prototype with all components from existing parts sold in the market has been assembled and tested. Estimated electrochemical reactions are discussed for initial charging process with Vanadium Pentoxide powder as initial state to obtain fully charged battery state with V2+ ion in anolyte and VO2 + ion in catholyte. Material corrosion testes were done by immersing the material in a Vanadium electrolyte and by using the material as a bipolar plate in the VRFB system. Immersion test showed that copper, steel, lead and zinc were corroded badly. In bipolar plate material test, stainless steel 316, aluminum and silver plates were corroded after some hours of electric charging process. Simple carbon plastic composites and 3-mm thickness graphite plates were tested in the bipolar plate material test and failed due to corrosion problem as well. In the VRFB prototype, corrosion problems occurred on brass nipples, polyurethane plastic pipes and porous silicone seals. Stronger plastic components and better quality of silicone seals are needed for VRFB. Significant finding of this study is possible spontaneous chemical reaction within anolyte tank as a potential of self-discharging reaction which other researchers have not identified. Also, another finding from this study is that good bipolar plate for VRFB is not easily available in the market.

Clean preparation of mixed trivalent and quadrivalent vanadium electrolyte for vanadium redox flow batteries by catalytic reduction with hydrogen

The vanadium redox flow battery (VRFB) is a promising technology for large-scale stationary energy storage systems. However, the high preparation cost of mixed valent vanadium electrolyte hinders the large-scale commercial application of VRFB. In this work, a simple, green and low-cost method is proposed to prepare the mixed valent vanadium electrolyte for VRFB. The clean hydrogen is chosen as the reducing agent to obtain trivalent vanadium ions from quadrivalent vanadium ions. The Pt/C material is used as the catalyst to accelerate the reduction rate at atmospheric pressure. The impurity-free mixed valent vanadium electrolyte, with a mean valence number of 3.5, prepared by the catalytic reduction process exhibits excellent battery performance with CE of 93% and EE of 85%. Furthermore, a catalytic reactor using Pt/C decorated graphite felt is designed and used to continuously produce the mixed valent vanadium electrolyte. According to the result of simple cost analysis, the proposed catalytic hydrogen reduction process can reduce theoretically the manufacturing cost by approximately 22.6% compared with the present industrial electrolytic process. As a consequence, the simple, clean and low-cost manufacture method of the mixed valent vanadium electrolyte exhibits remarkable competitiveness and promising potential for the practical production application of VRFB.

Facile Density Measurement Method for High-Concentration Sulfate Determination

In this study, a fast, facile and high accuracy method for high concentration sulfate determination is presented. The method is based on precipitation of sulfate ions with barium ions. The sulfate amount is quantified by measurement of the density of the barium and sulfate ion solutions before mixing, and the density of the supernatant after mixing. A calibration curve for sulfate concentration between 2.5 and 5.5 M in vanadium electrolyte was performed, obtaining a precision better than 0.7%, in agreement with a propagation-of-error analysis. Accuracy is determined by one-point calibration against a sample with known sulfate concentration and is at best the same as the precision. Within the precision of the method, no systematic effect of the presence of other ions/interferents (vanadium, phosphate) on the sulfate determination is observed.

Operando UV/Vis spectra deconvolution for comprehensive electrolytes analysis of vanadium redox flow battery

• 0.5 and 1 M vanadium electrolytes were successfully analyzed using the method. • The analysis provides reliable data regardless of supporting electrolyte composition. • V 2 O 3 3+ complex of posolyte was obtained using the proposed method. • Unknown residual absorbance of negolyte was registered using the deconvolution. • The method provides comprehensive data during VRFB cycling. Monitoring the state of charge (SoC) is one of the most important challenges of vanadium redox flow battery (VRFB) technology to solve. Among other methods, optical spectroscopy seems promising, however, existing approaches have their problems, primarily because of limited applicability for high vanadium concentrations, uncertainty in accounting for electrolyte imbalance during VRFB operation, and applicability limitations for mixed acid electrolytes. In this work, a method for determining SoC of VRFB based on the deconvolution of electrolyte absorption spectra is proposed. This method was successfully implemented for 0.5 M and 1 M vanadium electrolytes with 0.05 M phosphoric acid additive and demonstrated good accuracy for determining vanadium concentration and SoC in both half-cells, including analysis during VRFB galvanostatic cycling. Besides, this method allows us to obtain complex spectra: V 2 O 3 3+ in posolyte and a previously never demonstrated complex in negolyte that presumably corresponds to the V 3+ complex.

Calibration-free coulometric sensors for operando electrolytes imbalance monitoring of vanadium redox flow battery

It is necessary for vanadium redox flow battery (VRFB) to become more cost-effective due to long-term stable operation with minimal life-cycle maintenance for its further development. Despite the absence of self-discharge in idle mode, the available capacity of VRFB gradually decreases during the battery cycling. The capacity decrease is attributed to side reactions appearance, which increase the average oxidation state (AOS) of vanadium electrolyte. This negative effect can be minimized by periodic electrolyte capacity recovery. However, it is crucial to have reliable information on the electrolytes composition to conduct rebalancing efficiently and timely. Various methods for vanadium electrolyte assessment have been previously proposed, however, none of them can be used coupled with industrial VRFBs. In this work, we present an operando coulometric analysis of an electrolyte sample in a VRFB cell and its subsequent return to the bulk solution. The proposed approach outperforms other methods due to sensitivity of the signal to the overall vanadium content and AOS and stable performance under imbalance conditions. The analysis of AOS was verified by three methods – coulomb-counting, ex-situ spectrophotometry, and coulometry. Therefore, this method can be successfully used not only in lab-scale VRFB studies, but can also be coupled with industrial VRFB stacks.

Influence of Several Phosphate-Containing Additives on the Stability and Electrochemical Behavior of Positive Electrolytes for Vanadium Redox Flow Battery

The poor operational stability of electrolytes is a persistent impediment in building redox flow battery technology; choosing suitable stability additives is usually the research direction to solve this problem. The effects of five phosphate containing additives (including 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP), hexamethylene diamine tetramethylene phosphonic acid (HDTMPA), amino trimethylene phosphonic acid (ATMPA), sodium ethylenediamine tetramethylene phosphonate (EDTMPS), and diethyl triamine pentamethylene phosphonic acid (DTPMP)) on the thermal stability and electrochemical performance of the positive electrolyte of vanadium redox flow battery were investigated. With 0.5 wt% addition, most of the selected additives were able to improve the thermal stability of the electrolyte. HEDP and HDTMPA extended the stability time of the pentavalent vanadium electrolyte at 50 °C from 5 days (blank sample) to 30 days and 15 days, respectively. The electrochemical performance of the electrolyte was further investigated by cyclic voltammetry, steady state polarization, and electrochemical impedance spectroscopy tests. It was found that most of the additives enhanced the electrochemical activity of the positive electrolyte, and the diffusion coefficients, exchange current densities, and reaction rate constants of V(IV) species became larger with the addition of these additives. It is verified that the thermal stability and electrochemical stability of the electrolyte are significantly improved by the combination of ATMPA + HEDP or ATMPA + HDTMPA. This study provides a new approach to improve the stability of the positive electrolyte for vanadium redox flow battery.

Vanadium/Water Electrolyser for Recharge of Vanadium Oxygen Fuel Cells

The vanadium/oxygen fuel cell (VOFC) has evolved from developments to vanadium redox flow batteries (VRFB) for storage of renewable energy and perhaps for mobile applications. In VOFCs, oxygen is used to oxidise divalent vanadium ions to trivalent ions instead of the redox reactions of V(IV)/V(V) to achieve potentially higher energy densities and eliminate temperature stability problems associated with the energy storage medium compared to VRFBs. To charge a VOFC as an energy storage system, the discharge reactions have to be reversed with as few side reactions as possible. This process involves reducing trivalent vanadium ions to divalent vanadium ions through the application of electrical energy. The cathodic water generated during the discharge is used as the reductant. The water itself is oxidised to oxygen to keep the cycle between the charge and discharge processes as short and efficient as possible. This process is also exactly the reversal of the process which happens in VRFBs when atmospheric oxygen oxidizes divalent vanadium ions in vanadium electrolytes. As a synergistic effect, vanadium/water electrolysis can be also used to regenerate oxidized electrolytes and increase the life time of the batteries.Using a cell with a commercial and iridium-based catalyst coated membrane, it was possible to fully reduce V3.5+ and V3+ solutions to V2+ with the formation of oxygen and with coulomb efficiencies of over 96%. The process was followed by introduction of an additional reference electrode to measure the redox potential of the electrolyte, the negative electrode potential and to calculate the positive redox potential. The cell achieved a maximum current density of 75 mA/cm2 during this process and was limited by the proximity of the V(III) reduction to the hydrogen evolution reaction. Due to the specific reaction mechanisms of V(IV) and V(III) ions, V(III) solutions were reduced with an energy efficiency of 61%, making this process nearly twice as energy efficient as the reduction of V(IV) to V(III). Polarisation curves and electrochemical impedance spectroscopy were used to further investigate the losses of halfcell reactions and to find ways of further increasing efficiency and performance levels. Figure 1

A Novel, Membrane Free Redox Battery Design Using Organic/Inorganic Redox Pair in Aqueous System

The increasing demand to decarbonize the power grid is driving the development of low cost, sustainable and stable energy storage media. Redox flow batteries (RFB) have always been a strong candidate owing to their easy scalability, long cycle life and versatility. Modular design of RFB’s allows better control on energy and power density and many components of this battery, such as the electrolyte, ion-exchange membrane, and bipolar plates can be modified to better utilize the chemical energy stored in redox species [1]. The current state-of-the-art RFB uses vanadium electrolytes with Nafion as an ion-exchange membrane. However, the vanadium system has a limited energy density (around 35 Wh/L), limited availability and has electrolyte cross-over issues. Research in RFBs has been shifting towards redox-active aqueous-organic-based electrolytes consisting of Earth-abundant elements (C, H, O, N, S, F etc.), accommodating the need for green, safe, and low-cost energy storage [3]. Organic-based RFBs with energy densities over 100 Wh/L have been demonstrated [4]. However, studies show that the electrolyte cross-over issues limits organic RFBs as well. Finding a compatible ion-exchange membrane with long cycle life is a challenge that has impeded the growth of RFB in commercial markets for decades [4]. This research work proposes an aqueous-organic-electrolyte-based, membrane-free electrochemical cell to help eliminate membrane clogging issues. Our previous work has shown the proof of concept – a membrane free auxiliary electrode-based cell working for over one hundred cycles [5]. The auxiliary electrode setup enables high-energy-dense organic electrolytes and cells with one or two traditional compartments (catholyte, anolyte) can be employed. We believe this emerging membrane free design which still requires attention on fundamental scientific issues, can provides new opportunities for high-energy batteries for the future.

(Invited) State of Charge Monitoring of Vanadium Flow Batteries Using Spectroscopic and Electrochemical Methods

Vanadium Flow Batteries (VFBs) are a promising energy storage technology, particularly for large and medium scale applications. In a VFB, energy is stored in two vanadium electrolytes separated by a nafion membrane. The use of vanadium electrolytes in both half-cells minimises cross contamination issues which have plagued other flow battery chemistries. The electrodes, electrolytes and membrane are key areas of research for VFBs with the aim of improving efficiency, energy density and costs.Accurately monitoring state-of-charge (SoC) is vital for any rechargeable battery system. It is important to monitor the SoC of both half-cells simultaneously because of imbalances which occur due to side reactions and unwanted vanadium transfer across the membrane. The electrolyte may be rebalanced by various techniques but only if the SoC of each half-cell is accurately known. There are multiple possible techniques to monitor the SoC of each half-cell. We measure SoC in-situ by analysing the absorbance spectra of the vanadium electrolytes as they are charged and discharged. We also accurately measure volume changes throughout the cycle to study the water transfer through the nafion membrane. This accurate SoC data which is obtained will be compared with other SoC techniques. It will also be used to study the performance characteristics of the battery.Acknowledgements:This research was funded by the Sustainable Energy Authority of Ireland (Award Number 18/RDD/341).

Life cycle assessment of an industrial‐scale vanadium flow battery

In the course of the energy transition, storage technologies are required for the fluctuating and intermittently occurring electrical energy. The vanadium flow battery (VFB) is an especially promising electrochemical battery type for megawatt applications due to its unique characteristics. This work is intended as a benchmark for the evaluation of environmental impacts of a VFB, providing transparency and traceability. It considers the requirements for an industrial VFB from the technical and electrochemical point of view. The system design is based on a net capacity of 8 MWh and a net power of 1 MW. This ex ante study is a cradle-to-grave life cycle assessment (LCA) for a VFB to identify, analyze, and evaluate the environmental impacts for a lifetime of 20 years. Moreover, potential environmental impacts of several subsequent life cycles of the emission-intensive and long-lasting vanadium electrolyte are evaluated. With a focus on the electrolyte, the extraction process of vanadium pentoxide is studied in detail for the first time. Consequently, recommendations for the design of the life cycle of VFBs and for comparative LCAs with other energy storage technologies can be derived. Based on this work, more detailed work can follow, which helps to estimate the recycling potentials and emissions more precisely. This article met the requirements for a gold-gold JIE data openness badge described at https://jie.click/badges