In recent years, alkaline exchange membrane water electrolysis (AEM-WE) has attracted a lot of attention for its potential cost reduction compared to traditional electrolysis systems. Despite this promise, challenges related to efficiency and stability must be effectively addressed to fully realise the potential of AEM-WE. This paper presents a comprehensive investigation of an AEM-WE single-cell including electrochemical impedance spectroscopy (EIS) in conjunction with the equivalent circuit model (ECM). For the first time distribution of relaxation times (DRT) analysis is performed on an AEM-WE cell, employing a reversible hydrogen electrode (RHE) as a reference electrode. Half-cell EIS measurements and subsequent DRT spectra are presented, clearly indicating anodic and cathodic half-cell reactions. The DRT analysis reveals five distinct loss mechanisms in the AEM-WE system. These include the hydrogen evolution reaction, the oxygen evolution reaction, and ionic transport losses occurring within the catalyst layers. Through a systematic variation of the operating parameters we successfully allocate DRT peaks to their respective physicochemical origins. The findings contribute valuable insights into the electrochemical processes within the AEM-WE single-cell, offering a better understanding of the underlying mechanisms and facilitating the target-oriented development of enhanced membrane electrode assemblies.

中文翻译：

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阴离子交换膜电解动力学：利用电化学阻抗谱、参比电极和弛豫时间分布揭示损失机制

近年来，碱性交换膜水电解（AEM-WE）因其与传统电解系统相比潜在的成本降低而受到广泛关注。尽管有这样的承诺，但必须有效解决与效率和稳定性相关的挑战，以充分发挥 AEM-WE 的潜力。本文对 AEM-WE 单电池进行了全面研究，包括电化学阻抗谱 (EIS) 与等效电路模型 (ECM) 的结合。首次在 AEM-WE 电池上进行弛豫时间分布 (DRT) 分析，采用可逆氢电极 (RHE) 作为参比电极。提供了半电池 EIS 测量和随后的 DRT 光谱，清楚地表明了阳极和阴极半电池反应。 DRT 分析揭示了 AEM-WE 系统中五种不同的损失机制。这些包括析氢反应、析氧反应和催化剂层内发生的离子传输损失。通过系统地改变操作参数，我们成功地将 DRT 峰分配到它们各自的物理化学起源。这些发现为 AEM-WE 单电池内的电化学过程提供了宝贵的见解，可以更好地理解潜在机制，并促进增强型膜电极组件的目标导向开发。