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Description
Membranes play a vital role in systems exposed to electric fields, particularly in battery technologies, where they act as separators, preventing direct contact between electrodes while allowing controlled ion transport. In these environments, redox-active species, especially quinone-based redox couples, are known to interact with membrane surfaces, thereby influencing overall device performance. Such interactions can result in cross-diffusion of redox species, membrane fouling, and reduced ion-transport efficiency, including losses in proton conductivity. Despite their significance, the detailed interfacial behavior of redox-active species in the presence of electric fields remains an area that is still not fully understood, necessitating further investigation to improve membrane-based energy systems.
To address this gap, this study employs surface plasmon resonance (SPR) spectroscopy, a sensitive technique, to investigate these complex interactions. SPR enables real-time monitoring of adsorption processes on a variety of membrane materials and provides detailed insights into adsorption kinetics and changes in surface coverage over time. Moreover, SPR measurements clarify how the redox state of active species influences their interfacial behavior under different conditions. The experimental setup consists of an electrochemical flow cell equipped with a gold working electrode, a solid-state Ag/AgCl reference electrode, and a platinum counter electrode, enabling precise control of applied potentials. Through this setup, the study systematically compares the adsorption characteristics of redox-active species at the membrane interface both in the presence and absence of an external electric field, offering new perspectives on how electric fields modulate these phenomena.
Preliminary cyclic voltammetry analysis of the electrolyte has indicated species crossover, underscoring the necessity of understanding membrane–electrolyte interactions in these systems. The findings from this investigation are anticipated to provide valuable insights into the mechanisms by which redox-active species and electric fields collectively influence membrane interfaces. Ultimately, these insights will contribute to a deeper explanation of performance degradation in electrochemical systems, such as batteries and fuel cells, where membranes are critical components. By elucidating these interfacial phenomena, the study aims to inform the design of more robust and efficient membrane materials for future energy storage and conversion technologies.