Performance of a Homemade Vanadium-Manganese Redox Flow Battery using Electrospun Carbon Electrode Catalyst and its Preliminary System Integration

In this study, the possibility of enhancing the performance of the all-vanadium redox flow battery (VRFB) and a vanadium/manganese redox flow battery (V/Mn RFB) using carbonized catalyst layers (CCLs) prepared via electrospinning is considered. To display performance enhancement caused by such catalysts, a home-made reactor with non-optimized compression and serpentine flow fields was employed. This reactor was manufactured using a combination of recycled metals, graphite and chemically resistant plastic, with serpentine flow fields engraved using in-house computer aided manufacture employing SolidWorks software. The surface morphologies of the graphite and carbon-based electrodes used during electrochemical tests were characterized by SEM and XRD analyses. For such a non-optimized reactor, the application of the CCL as an additional material to an as-received graphite felt electrode shows improvements for both vanadium-based RFB technologies. For instance, the enhancements in power densities of VRFBs were achieved by 30% improvement in peak power density using CCL. V/Mn flow batteries showed 50% improvement in capacity utilization when using CCL. It is also postulated that because the CCL needs to be placed between the flow fields and the felt electrodes to prevent fiber protrusion into the flow channels when compressed in the reactor, the peak power densities and cycling efficiencies were lower than those reported for optimized RFBs in the literature. The need to improve the power density is a critical consideration for RFBs. A high-power density translates into lower capital costs for V/Mn RFBs, which translates into an effective system integration for grid-scale load levelling, water desalination or renewable energy storage.