Effectiveness of proline as a thermal stability agent for high-temperature-tolerance electrolyte in a working VRFB

초록

This paper presents an effectiveness of proline in positive electrolytes for enhancing the thermal stability and performance of vanadium redox flow batteries (VRFBs) at elevated temperatures. Proline not only facilitates the redox reactions of VO2+/VO2+ through its catalytic effect but also reduces vanadium crossover and limits V2O5 formation via its coordination complexing effect. The effectiveness of proline is demonstrated through various electrochemical experiments, including harsh limit-testing up to 120 mA/cm2 and 80 °C, and full-cell tests conducted over 100 cycles at 50 °C. The results indicate that proline significantly enhances the thermal and electrochemical stability of the VRFB electrolyte. This improvement is attributed to the excellent coordination and catalytic capability of carboxyl (-COOH) and protonated secondary amine (-NH2+) groups in its molecular structure. The superior electrochemical performance of proline as a thermal stability agent is evidenced by the proline-supported electrolyte, which exhibits remarkable thermal stability and improved performance over 100 cycles at 50 °C, including a high average energy efficiency of 65.57% compared to 55.97% for the pristine electrolyte, and a significantly enhanced discharge capacity retention of 51.54% at the 100th cycle, compared to just 1.51% for the pristine electrolyte. © 2026 Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

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