[论文解读] Bias-triggered conductivity relaxation (BCR): a unique tool to simultaneously investigate thermodynamics, kinetics and electrostatic effects of oxygen reactions in MIEC thin films

Alexander Stangl, Alexander Schmid+3 more|arXiv (Cornell University)|Jan 22, 2026

Advancements in Solid Oxide Fuel Cells被引用 0

一句话总结

引入偏置触发的导电率松弛（BCR）作为一种新方法，能够同时探测混离子-电子导体（MIEC）薄膜中的氧反应的热力学、动力学和静电效应，演示在（La,Sr）FeO3−δ 电极上。

ABSTRACT

Mixed ionic electronic transfer (MIET) reactions, such as the oxygen reduction reaction (ORR) at oxide surfaces, are of paramount importance to manifold technologically highly relevant processes and fundamental understanding must be developed to improve performance and tailor highly efficient electrodes and catalysts. Understanding such complex multi-step reactions, requires the study of kinetic processes, underlying thermodynamic properties, i.e. ionic and electronic defect concentrations and electrostatic surface effects. However conventional techniques struggle to uncover the complete picture within the same sample/measurement. Here, we overcome this limitation by introducing bias-triggered conductivity relaxation (BCR) as a novel tool to investigate MIET reactions on oxides. It is based on alternating out-of-plane coulometric titration/polarization and in-plane electrical conductivity relaxation measurements, providing simultaneous electronic, ionic and extraordinarily rich surface kinetics information. This innovative combination of electrical and chemical driving forces synergizes information depth, with enhanced time resolution, versatility and speed, yet it lifts the weaknesses of the individual approaches, while remaining cost-effective and surprisingly simple. Furthermore, BCR allows to disentangle overpotential induced electrostatic modifications of the surface kinetics in a unique manner. We showcase the advantages of BCR in this work by studying the ORR in model (La,Sr)FeO$_{3-δ}$ thin film electrodes and reporting on their thermodynamic and kinetic properties.

研究动机与目标

• 需要理解氧化物表面的 MIET 反应（如 ORR）以改进电极和催化剂的动机。
• 提出一种方法，在同一样品中联合揭示热力学缺陷浓度、动力学过程和静电表面效应。
• 展示该方法在分离表面动力学的静电过电势效应方面的能力。

提出的方法

• 引入偏置触发的导电率松弛（BCR），结合库仑滴定/极化与面内导电率松弛。
• 通过交替的面外驱动与面内导电率测量，提取电子和离子响应。
• 利用电驱动力与化学驱动力的协同效应，提高时间分辨率和信息深度。
• 在模型薄膜（La,Sr）FeO3-δ 上演示该方法，以获得热力学和动力学参数。
• 突出在表面动力学的过电势诱导静电修饰的解耦能力。

实验结果

研究问题

• RQ1 如何以同时提取热力学、动力学和静电信息的方式探测氧化物表面的 MIET 反应？
• RQ2 偏置触发的导电率松弛是否能揭示离子/电子缺陷浓度与表面静电在 MIEC 薄膜上 ORR 过程中的相互作用？
• RQ3 通过 BCR 可以揭示的在（La,Sr）FeO3-δ 薄膜电极的 ORR 的热力学与动力学特性有哪些？

主要发现

• BCR 提供来自单一样本在综合电气与化学驱动下的同时电子、离子以及丰富的表面动力学信息。
• 该方法能够以前所未有的方式解耦过电势引起的表面动力学静电修改。
• 应用到（La,Sr）FeO3-δ 薄膜可获得其 ORR 的热力学和动力学洞见（具体数值在摘要中未给出）。
• 与传统技术相比，BCR 提供更高的时间分辨率、多功能性及成本效益。