Kourosh Khaje, , , Behzad Fuladpanjeh-Hojaghan, , , Jürgen Gailer, , , Viola Birss, , and , Edward P. L. Roberts*,
{"title":"Chemical Hazard Assessment of Asymmetric Vanadium Flow Battery Electrolytes in Failure Mode","authors":"Kourosh Khaje, , , Behzad Fuladpanjeh-Hojaghan, , , Jürgen Gailer, , , Viola Birss, , and , Edward P. L. Roberts*, ","doi":"10.1021/acs.chas.5c00098","DOIUrl":null,"url":null,"abstract":"<p >Emerging battery technologies are transforming the landscape of energy storage. Within this domain, flow batteries are increasingly seen as critical enablers for the integration and deployment of renewable energy systems. Nevertheless, the electrolytes utilized in these systems present potential risks to both human health and environmental safety. Over the past five decades, vanadium–vanadium flow batteries have become a commercially viable solution; however, several distinct electrolyte compositions have been proposed for asymmetric vanadium flow batteries (V-X FB: X = Ce, Br, Fe, Mn, Zn, H<sub>2</sub>, O<sub>2</sub>), each driven by unique technical and commercial motivations. This study aims to evaluate their risks, prioritize further research investments, and identify gaps in current efforts to advance safer and more sustainable energy storage technologies. This research builds on our prior work, entitled <i>Chemical Hazard Assessment of Vanadium–Vanadium Flow Battery Electrolytes in Failure Mode</i>, [ <contrib-group><span>Khaje, K.</span></contrib-group> <cite><i>ACS Chem. Health Saf.</i></cite> <span>2025</span>, <em>32</em>, 449–460]. But shifts the focus to asymmetric vanadium flow batteries that are at a lower technology readiness level and are earlier in the commercialization pathway. Overcharging of batteries has been identified as one of the primary potential failure modes, directly leading to electrolyte degradation. This condition poses significant hazards due to the potential generation of toxic gases. Depending on the electrolyte composition, overcharging may result in the release of gases, such as Cl<sub>2</sub>, Br<sub>2</sub>, SO<sub>2</sub>, H<sub>2</sub>S, PH<sub>3</sub>, NO<sub>2</sub>, CO<sub>2</sub>, NH<sub>3</sub>, or HCN, each carrying immediate risks to human health. This study shows that electrolytes containing bromide, chloride, and cyanide ions are particularly concerning, as they present the most severe toxicity hazards during failure modes. Future experimental work is needed to evaluate conditions under which gases are produced by these flow batteries under both normal and severe overcharging conditions and to quantify the associated hazards. This will provide critical insights for improving battery safety and guiding future research and development in energy storage technologies.</p>","PeriodicalId":73648,"journal":{"name":"Journal of chemical health & safety","volume":"32 5","pages":"637–648"},"PeriodicalIF":3.4000,"publicationDate":"2025-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of chemical health & safety","FirstCategoryId":"1085","ListUrlMain":"https://pubs.acs.org/doi/10.1021/acs.chas.5c00098","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
Emerging battery technologies are transforming the landscape of energy storage. Within this domain, flow batteries are increasingly seen as critical enablers for the integration and deployment of renewable energy systems. Nevertheless, the electrolytes utilized in these systems present potential risks to both human health and environmental safety. Over the past five decades, vanadium–vanadium flow batteries have become a commercially viable solution; however, several distinct electrolyte compositions have been proposed for asymmetric vanadium flow batteries (V-X FB: X = Ce, Br, Fe, Mn, Zn, H2, O2), each driven by unique technical and commercial motivations. This study aims to evaluate their risks, prioritize further research investments, and identify gaps in current efforts to advance safer and more sustainable energy storage technologies. This research builds on our prior work, entitled Chemical Hazard Assessment of Vanadium–Vanadium Flow Battery Electrolytes in Failure Mode, [ Khaje, K.ACS Chem. Health Saf.2025, 32, 449–460]. But shifts the focus to asymmetric vanadium flow batteries that are at a lower technology readiness level and are earlier in the commercialization pathway. Overcharging of batteries has been identified as one of the primary potential failure modes, directly leading to electrolyte degradation. This condition poses significant hazards due to the potential generation of toxic gases. Depending on the electrolyte composition, overcharging may result in the release of gases, such as Cl2, Br2, SO2, H2S, PH3, NO2, CO2, NH3, or HCN, each carrying immediate risks to human health. This study shows that electrolytes containing bromide, chloride, and cyanide ions are particularly concerning, as they present the most severe toxicity hazards during failure modes. Future experimental work is needed to evaluate conditions under which gases are produced by these flow batteries under both normal and severe overcharging conditions and to quantify the associated hazards. This will provide critical insights for improving battery safety and guiding future research and development in energy storage technologies.