Dataset for Understanding the degradation process in zinc-iodine hybrid flow batteries

This dataset contains all measurements collected during the investigation of the degradation phenomenon known as the voltaic bulge, observed in zinc-iodine hybrid flow batteries (ZIHFBs). The voltaic bulge is characterized by a sharp increase in charging voltage followed by a sudden drop, and its presence correlates with a decline in battery performance. To understand the origin of this phenomenon and identify safe operating conditions, the study employed various electrochemical techniques, including galvanostatic cycling, combined galvanostatic and potentiostatic cycling, and electrochemical impedance spectroscopy (EIS) in both potentio (PEISOCV) and galvano (GEISLOAD) modes. Additionally, various single-cell construction modifications were implemented to deepen our understanding of the phenomenon. These included the use of non-conductive felt (NCF) in combination with graphite felt (GF), and the connection of electrolyte tanks via a thin capillary referred to as a hydraulic shunt (HS). Furthermore, the study explored the effects of different electrolyte compositions, such as omitting ZnI₂ from the posolyte and increasing the concentration of tri-iodide ions in the posolyte. The findings presented in this manuscript provide insights into the mechanisms behind the voltaic bulge and offer guidelines for optimizing ZIHFB operation to mitigate its impact.本数据集涵盖了针对锌碘复合液流电池（zinc-iodine hybrid flow batteries, ZIHFBs）中观测到的伏升压降（voltaic bulge）降解现象开展研究期间采集的全部测量数据。该伏升压降现象以充电电压先急剧升高后突然下降为特征，其出现与电池性能衰减密切相关。为明晰该现象的成因并确定安全运行工况，本研究采用了多种电化学测试技术，包括恒电流循环、恒电流-恒电位复合循环，以及恒电位开路电化学阻抗谱（PEISOCV）和恒电流负载电化学阻抗谱（GEISLOAD）两种模式下的电化学阻抗谱（electrochemical impedance spectroscopy, EIS）。此外，研究团队还通过多种单电池结构改造方案深化对该现象的理解，包括将非导电毡（NCF）与石墨毡（GF）组合使用，以及通过被称为液压分流器（HS）的细毛细管连接电解液储罐。同时，本研究还探究了不同电解液组分的影响，例如省略正极电解液（posolyte）中的ZnI₂，以及提高正极电解液中三碘离子的浓度。本稿件呈现的研究结果揭示了伏升压降现象背后的作用机制，并为优化锌碘复合液流电池（ZIHFBs）的运行以缓解该现象的不良影响提供了指导性原则。