Detection of capacity imbalance in vanadium electrolyte and its electrochemical regeneration for all-vanadium redox-flow batteries

Roznyatovskaya, Nataliya; Herr, Tatjana; Küttinger, Michael; Fühl, Matthias; Noack, Jens; Pinkwart, Karsten; Tübke, Jens

doi:10.1016/j.jpowsour.2015.10.021

Cited by 68 publications

(38 citation statements)

References 7 publications

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“…There are straightforward methods that can be used to balance the volume and vanadium concentration of the electrolytes (mixing, splitting the electrolytes in two equal portions), whereas balancing the AOS is more demanding: for example, chemical treatment with reducing agents, mixing with extra vanadium electrolytes, or electrochemical methods such as electrolysis have been investigated. Determining the AOS is required before conducting compensation measures for imbalanced AOS.…”

Section: Introductionmentioning

confidence: 99%

Electrolyte Imbalance Determination of a Vanadium Redox Flow Battery by Potential‐Step Analysis of the Initial Charging

Beyer¹,

Austing²,

Satola³

et al. 2020

ChemSusChem

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Vanadium redox flow batteries (VRFB) suffer from capacity fades owing to side reactions and crossover effects through the membrane. These processes lead to a deviation of the optimal initial average oxidation state (AOS=+3.5) of vanadium species in both half‐cell electrolytes. To rebalance the electrolyte solutions, it is first necessary to determine the current AOS. In this study, a new method was developed that enables an accurate determination of the AOS. A potential‐step analysis was performed with mixed electrolyte solutions of both half‐cells during the initial charging. The potential was recorded with a simple open‐circuit voltage (OCV) cell, and the potential‐steps were analyzed. A correlation between the duration of the potential plateaus in the OCV and the amount of vanadium ions of a certain oxidation state in the half‐cell electrolytes was found and used to precisely determine the AOS with a maximum error of 3.6 %.

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Section: Introductionmentioning

confidence: 99%

Electrolyte Imbalance Determination of a Vanadium Redox Flow Battery by Potential‐Step Analysis of the Initial Charging

Beyer¹,

Austing²,

Satola³

et al. 2020

ChemSusChem

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“…After 3 years of operation, advanced corrosion of the carbon electrodes and bipolar plates was observed (Figure ). Spectrophotometric analysis of the electrolyte indicated an imbalance of 20 % between the positive electrolyte and the negative electrolyte …”

Section: Introductionmentioning

confidence: 99%

“…Spectrophotometric analysis of the electrolyte indicated an imbalance of 20 %b etween the positive electrolyte and the negative electrolyte. [17] The presence of cracks on the terminal bipolar plate used as an electrical contact to acurrent collector allowed adirect connectionb etween the positive electrolyte and the copper current collector ( Figure 3). Dissolution of coppert ook place and causedatotal failure of the stack.…”

Section: Introductionmentioning

confidence: 99%

On‐Site Purification of Copper‐Contaminated Vanadium Electrolytes by using a Vanadium Redox Flow Battery

et al. 2019

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Corrosion of carbon‐based electrodes and bipolar plates is a major hurdle and can be a cause of failure in commercial vanadium redox flow batteries (VRFBs). Carbon corrosion was found to occur in a commercial VRFB (10 kW/40 kWh), whereby cracks through bipolar plates enabled the electrolyte to leach the copper current collectors at the end of the stacks, contaminating the entire electrolyte solution. In this work, the effects of copper contaminants on the operation of a VRFB were studied. A simple and effective procedure to identify copper contamination on‐site and to purify the electrolyte was developed. The process was used to purify large quantities (6000 L) of copper‐contaminated electrolytes to levels below 1 ppm.

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“…RFBs have great potential as next‐generation ESSs as they can be flexibly configured according to the power demand, where the power and energy capacity can be independently designed in the RFB system. In addition, the recycling of electrolytes by rebalancing is a great advantage of RFBs . Metal redox couples, such as all‐vanadium, zinc/bromine, and iron/chrome couples, are used in most RFBs.…”

Section: Introductionmentioning

confidence: 99%

“…In addition, the recycling of electrolytes by rebalancing is a great advantage of RFBs. 7 Metal redox couples, such as all-vanadium, zinc/bromine, and iron/chrome couples, are used in most RFBs. All-vanadium RFBs (VRFBs) are considered promising candidates for future ESSs because VRFBs use common active materials for both electrodes, which makes it easy to recycle the electrolytes, although the anolyte and catholyte suffer from contamination due to crossover.…”

Section: Introductionmentioning

confidence: 99%

Comprehensive study of the performance of alkaline organic redox flow batteries as large‐scale energy storage systems

2019

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Summary Alkaline‐based organic redox flow batteries (AORFBs) attract significant interest because they can retain the advantages of vanadium redox flow batteries (VRFBs) while being low‐cost because expensive vanadium is replaced with easily synthesizable metal‐free organic compounds and earth‐abundant raw materials. A comprehensive experimental study on the performance of AORFBs using alloxazine 7/8‐carboxylic acid (ACA) and ferrocyanide was conducted to investigate the feasibility of these batteries as large‐scale energy storage systems. The operating conditions, such as the electrolyte concentration, flowrate, and temperature, were varied in this study. The results show that the present AORFB achieves an energy efficiency above 76% at 80 mA cm−2 at elevated temperature (55°C). Compared with those of VRFBs, AORFBs exhibit very good thermal stability and capacity retention. A large‐scale AORFB was constructed and tested to confirm the effectiveness of AORFBs.

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Detection of capacity imbalance in vanadium electrolyte and its electrochemical regeneration for all-vanadium redox-flow batteries

Cited by 68 publications

References 7 publications

Electrolyte Imbalance Determination of a Vanadium Redox Flow Battery by Potential‐Step Analysis of the Initial Charging

Electrolyte Imbalance Determination of a Vanadium Redox Flow Battery by Potential‐Step Analysis of the Initial Charging

On‐Site Purification of Copper‐Contaminated Vanadium Electrolytes by using a Vanadium Redox Flow Battery

Comprehensive study of the performance of alkaline organic redox flow batteries as large‐scale energy storage systems

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