(1. 武汉科技大学 资源与环境工程学院，武汉 430081；
2. 攀钢集团研究院有限公司 钒钛资源综合利用国家重点实验室，攀枝花 617000；
3. 武汉科技大学 国家环境保护矿冶资源利用与污染控制重点实验室，武汉 430081；
4. 武汉科技大学 钒资源高效利用湖北省协同创新中心，武汉 430081；
5. 武汉科技大学 湖北省页岩钒资源高效清洁利用工程技术研究中心，武汉 430081；
6. 武汉理工大学 资源与环境工程学院，武汉 430070)
摘 要: 为提高钒电池电解液的能量密度及宽温度区间稳定性，对基于硫酸-盐酸混酸支持电解质体系的电解液进行稳定性及电化学性能优化。对电解液进行钒离子及氯离子稳定性测试，发现在支持电解质配比为硫酸根浓度2.0~3.0 mol/L、氯离子浓度6.0~6.4 mol/L时，电解液钒浓度可达2.4 mol/L且四种价态的电解液均可在-20~50 ℃稳定存在10 d以上且可以有效避免氯化氢挥发。对稳定性优化后的电解液进行循环伏安及交流阻抗测试，发现在钒浓度为2.2 mol/L、硫酸根浓度为2.75 mol/L、氯离子浓度为5.8 mol/L时，电解液的电化学性能最佳。对浓度组成优化的电解液进行充放电测试，发现电解液可以在-20~50 ℃及40~80 mA/cm2稳定运行，且能量效率可达75%。
关键字: 钒电池；电解液；稳定性；电化学性能
（1. College of Resource and Environment Engineering, Wuhan University of Science and Technology, Wuhan 430081, China;
2. State Key Laboratory of Vanadium and Titanium Resources Comprehensive Utilization, Pangang Group Research Institute Co., Ltd., Panzhihua 617000, China;
3. State Environmental Protection Key Laboratory of Mineral Metallurgical Resources Utilization and Pollution Control, Wuhan University of Science and Technology, Wuhan 430081, China;
4. Hubei Collaborative Innovation Center of High Efficient Utilization for Vanadium Resources, Wuhan University of Science and Technology, Wuhan 430081, China;
5. Hubei Provincial Engineering Technology Research Center of High Efficient Cleaning Utilization for Shale Vanadium Resource, Wuhan University of Technology, Wuhan 430081, China;
6. College of Resource and Environment Engineering, Wuhan University of Technology, Wuhan 430070, China）
Abstract:In order to improve the energy density and broad temperature adaptability of vanadium redox flow battery, the stability and electrochemical performance of electrolyte based on sulfate-chloride mixed acid electrolyte were optimized systematically. The static stability tests of vanadium ions and chloride ions show that the electrolyte of 2.4 mol/L vanadium concentration can keep stable for 10 d and the volatilization of hydrogen chloride can be effectively avoided when chloride ion concentration is 6.0-6.4 mol/L and sulfate concentration is 2.0-3.0 mol/L. The CV and EIS tests of electrolyte after stability optimization indicate that the electrolyte with 2.2 mol/L vanadium concentration, 2.75 mol/L sulfate concentration and 5.8 mol/L chloride ion concentration presents the best electrochemical performance. The charge-discharge tests of optimized electrolyte indicate that the VRFB with optimized electrolyte composition can be operated successfully at the temperature of -20－50 ℃ and the current density of 40-80 mA/cm2, and the energy efficiency can reach 75%.
Key words: vanadium redox flow battery; electrolyte; stability; electrochemical performance
