Microelectrode-Based Sensor for Measuring Operando Active Species Concentrations in Redox Flow Cells
Microelectrode-Based Sensor for Measuring Operando Active Species Concentrations in Redox Flow Cells
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DOI：
10.1021/acsaem.1c02580
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发表时间：
2021-12-27
影响因子：
6.4
通讯作者：
Brushett, Fikile R.
中科院分区：
文献类型：
--
作者：
Neyhouse, Bertrand J.;Tenny, Kevin M.;Brushett, Fikile R.
对氧化还原液流电池候选材料的评估需要有效的诊断技术来监测电解质荷电状态和健康状态的演变，以询问系统行为随时间的变化。此外，这样的工具可以应用于实际实施例中以告知维护计划并优化能源利用。在这项工作中，我们开发并测试了一种基于微电极的流通式电化学传感器，以连续测量氧化还原流通池中的活性物质浓度。将金微电极（工作电极）和铂丝（伪参比电极）密封到不锈钢配件（对电极）中，并使用三电极电分析技术（即伏安法、计时电流法）将稳态电流与浓度相关联。为了验证控制传感机制的传输和热力学，我们将多物理场模拟与异位实验测试相结合，确认该设备能够准确确定单个物种的浓度。然后，我们评估对称氧化还原流通池中的微电极传感器，展示该方法在测量操作物浓度方面的实用性，并讨论成功实施的其他注意事项（例如，测量协议、材料选择、流通池设计）。该传感器由市售的现成组件组装而成，可以很容易地被研究实验室采用并集成到现有的实验工作流程中，使其成为研究液流电池材料的有前途的工具。
The assessment of candidate materials for redox flow batteries requires effective diagnostic techniques for monitoring the evolution of electrolyte state of charge and state of health to interrogate time-dependent changes in system behavior. Further, such tools can be applied in practical embodiments to inform maintenance schedules and optimize energy utilization. In this work, we develop and test a flow-through, microelectrode-based electrochemical sensor to continuously measure active species concentrations in redox flow cells. A gold microelectrode (working electrode) and platinum wire (pseudoreference electrode) are sealed into a stainless steel fitting (counter electrode), and three-electrode electroanalytical techniques (i.e., voltammetry, chronoamperometry) are performed to correlate steady-state current to concentration. To validate transport and thermodynamics that govern the sensing mechanism, we combine multiphysics simulation with ex situ experimental testing, confirming that the device is capable of accurately determining individual species concentrations. We then evaluate the microelectrode sensor in a symmetric redox flow cell, demonstrating the utility of this approach for measuring operando concentrations, and discuss additional considerations for successful implementation (e.g., measurement protocol, material selection, flow cell design). Assembled from commercially available, off-the-shelf components, the sensor can be readily adopted by research laboratories and integrated into existing experimental workflows, making it a promising tool for studying flow battery materials.