REACTION KINETICS OF VANADIUM SPECIES ON FUNCTIONALIZED ELECTRODES OF VANADIUM REDOX FLOW BATTERD2S

摘要

Vanadium redox flow batteries (VRFBs) are a promising energy storage technology that offers unique advantages over conventional batteries when used in conjunction with large-scale renewable energy sources (i.e. solar, wind). Although VRFBs are slowly approaching the commercialization stage, much research is still required in order to address the capacity loss issue that greatly affects the performance and lifetime of these systems (1-2). Due to experimental limitations, significant effort has now being placed on developing computational models to study and better understand the mechanisms responsible for capacity loss during operation (3). While the modeling studies enable rapid analysis of the system performance, their predictions strongly depends on the input parameters, which are used to describe the materials and system operations. To date, majority of these parameters in the models are mostly approximated or used as fitting parameters, which might greatly impact the reliability of the model predictions. For instance, in the literature, very little information is available regarding kinetic parameters (e.g., reaction rate constant, k, and charge transfer coefficient, a) for carbon felt electrodes, which are commonly used in VRFB systems. To the best of the authors' knowledge, the current VRFB models use the same reaction rate-constant and charge transfer coefficient for both oxidation and reduction reactions, which are in fact different. In this study, our goal was to determine these key kinetic parameters for differently functionalized electrodes in order to provide a reliable database for modelers.