Flow battery electroanalysis 3: online kinetics measurements using ultramicroelectrodes in channel flow,Journal of Materials Chemistry A

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Flow battery electroanalysis 3: online kinetics measurements using ultramicroelectrodes in channel flow
Journal of Materials Chemistry A ( IF 10.7 ) Pub Date : 2022-06-21 , DOI: 10.1039/d2ta02132c
Becca Segel ₁ , Zachary Parr ₁ , Tejal V. Sawant ₁ , Carissa S. Yim ₁ , Dean M. Miller ₁ , Thomas J. Henry ₁ , James R. McKone ₁

Affiliation

Redox flow batteries are attractive for grid-scale energy storage, but ongoing work on materials discovery is hampered by the difficulty of measuring electron-transfer rates under battery-relevant conditions. We have developed an experimental approach for collecting continuous voltammetric measurements of flow battery electrolytes by placing a 3-electrode cell containing an ultramicroelectrode into the flow loop of a functioning redox flow battery. We further developed an empirical approach for extracting electron-transfer rate constants from each voltammetric cycle, thereby enabling continuous measurements as a function of state of charge and cycle time. Benchmarking these approaches with iron-based aqueous flow battery electrolytes using platinum and carbon fiber ultramicroelectrodes yielded rate constants that varied in the order Pt > electrochemically oxidized carbon > pristine carbon, in good agreement with prior work. We also found that Pt electrodes become more catalytically active upon cycling for several hours, whereas carbon fiber electrodes with and without oxidative pretreatments remained stable over the same interval. We expect these experimental approaches can be used to measure kinetics and other figures of merit for most electrodes and electrolytes of interest for redox flow batteries as well as in other systems where it is useful to evaluate the properties of a flowing electrolyte in real time.

中文翻译：

液流电池电分析 3：在通道流中使用超微电极进行在线动力学测量

氧化还原液流电池对于电网规模的能量存储很有吸引力，但是由于在电池相关条件下测量电子转移率的困难，正在进行的材料发现工作受到阻碍。我们开发了一种实验方法，通过将含有超微电极的 3 电极电池放入功能性氧化还原液流电池的流动回路中来收集液流电池电解质的连续伏安测量值。我们进一步开发了一种经验方法，用于从每个伏安循环中提取电子转移速率常数，从而使连续测量成为充电状态和循环时间的函数。使用铂和碳纤维超微电极以铁基水系液流电池电解质对这些方法进行基准测试，得到的速率常数按 Pt > 的顺序变化电化学氧化碳 > 原始碳，与之前的工作非常一致。我们还发现 Pt 电极在循环数小时后变得更具催化活性，而经过和不经过氧化预处理的碳纤维电极在相同的时间间隔内保持稳定。我们预计这些实验方法可用于测量大多数电极和氧化还原液流电池感兴趣的电解质的动力学和其他品质因数，以及在其他系统中实时评估流动电解质的特性。而经过和不经过氧化预处理的碳纤维电极在相同的时间间隔内保持稳定。我们预计这些实验方法可用于测量大多数电极和氧化还原液流电池感兴趣的电解质的动力学和其他品质因数，以及在其他系统中实时评估流动电解质的特性。而经过和不经过氧化预处理的碳纤维电极在相同的时间间隔内保持稳定。我们预计这些实验方法可用于测量大多数电极和氧化还原液流电池感兴趣的电解质的动力学和其他品质因数，以及在其他系统中实时评估流动电解质的特性。

更新日期：2022-06-21

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