Vanadium Redox Flow Battery Electrode Derived from Electrodeposition of a Copper-based Metal-Organic Framework onto Lead Dioxide

Abstract

Metal-organic frameworks (MOFs) are metal-cation-containing structural building units connected into crystalline nets via organic linkers, and they often possess high surface area and coordinatively unsaturated metal ions, both features that make MOFs appealing candidates for electrochemical applications. Vanadium redox flow batteries (VRFBs), which hold promise for use in stationary grid-level electrochemical energy storage, are one such area of potential application that may serve to benefit from the properties of MOFs. Enhancing the redox kinetics of the VO2+/VO2+ reaction at the positive electrode of the VRFB can improve the power capabilities and cycle life of the battery. The extensive porosity of MOFs can serve to increase the reactive surface area of current VRFB electrodes and potentially offer a greater number of catalyst sites by means of oxygen functionals inherently present in MOFs. Lead dioxide electrochemically deposited on carbon felt is used as a substrate for electrochemical deposition of a well-known Cu-based MOF. Subsequent pyrolysis of the coated carbon felt and placement in a VRFB half-cell yields results that suggest more facile electrode kinetics and performance that matches or exceeds several other treated electrodes mentioned in current literature. Consequently, the evidence indicates that MOF-derived structures on carbon felt have significant potential to improve overall VRFB performance.