A green europium-cerium redox flow battery with ultrahigh voltage and high performance

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2024-11, Vol.500, p.157189, Article 157189
• Main Authors: Wu, Yating, Zhou, Lei, Xie, Yangyang, Lai, Yaobin, Fu, Shangwan, Kang, Xingchen, Shi, Wenhui, Li, Jian, Zhang, Xuxia, Hu, Kang, Zhang, Hui, Qi, Tao
• Format: Article
• Language: English
• Subjects: Aqueous redox flow batteries; High voltage; Non-toxic
• ISSN: 1385-8947
• DOI: 10.1016/j.cej.2024.157189

•A green Eu-Ce acidic aqueous liquid flow battery with high voltage and non-toxic characteristics is presented.•The composition of the electrolyte is optimized by comparing physicochemical characteristics and electrochemical performance.•The superiority in reducing water migration during long-term cycle is demonstrated by both DFT calculation and experiments.•Remarkable electrochemical performance is achieved in long-term cycle process. Due to the superiority of decoupled energy and power, high safety, and design flexibility, redox flow batteries (RFBs) have gained much attention as candidates for large-scale electrochemical energy storage. However, the main redox flow batteries like iron-chromium or all-vanadium flow batteries have the dilemma of low voltage and toxic active elements. In this study, a green Eu-Ce acidic aqueous liquid flow battery with high voltage and non-toxic characteristics is reported. The Eu-Ce RFB has an ultrahigh single cell voltage of 1.96 V. The high concentration of electrolyte enables the full-cell energy density to reach 43 Wh/L. Even at the current density of 100 mA cm−2 over 100 cycles, the average coulombic efficiency, voltage efficiency and energy efficiency can reach 98 %, 84 %, and 82.4 %, respectively. In comparison with other reported representative redox flow batteries in recent years, the practical power density calculated at 80 % energy efficiency is at a leading level. These demonstrate the Eu-Ce RFB is a promising solution for green large-scale renewable energy storage.