Enhancing Catalytic Activity and Stability of Carbon-Based Electrodes for Vanadium Redox Flow Batteries

<p>Vanadium Redox Flow Batteries (VRFBs) show potential for storing renewable energy, but their inefficiency hinders their broad adoption in energy utilization. This obstacle arises from the insufficient catalytic performance of traditional carbon-based electrodes. Graphite felt (GF) is extensively utilized as an electrode in VRFBs. Nevertheless, its poor reversibility and low electrochemical activity limit its widespread adoption in large-scale VRFB applications. Our research uses novel, eco-friendly approaches to enhance VRFB electrode performance. In the initial method, cost-effective and highly conductive carbon black (CB) is integrated as a catalyst onto the graphite felt using a deposition technique facilitated by the binder polymer poly (acrylic acid) (PAA). Subsequently, a high-temperature thermal treatment is applied to activate the felt and degrade the PAA binder, thereby diminishing ohmic resistance. In a secondary strategy, we investigate sustainability and recycling by employing discarded cloth, particularly unused cotton fabric, as electrodes for VRFBs. Biomass-derived carbonized wasted cloth (CWC) electrodes are produced via a straightforward carbonization procedure, eliminating the necessity for post-activation typically required with commercial graphite felts. Characterization of these electrodes reveals significant inter-fiber linkages, thereby decreasing ohmic resistance and improving charge transfer. Galvanostatic charge-discharge profiles reveal a notable enhancement in energy efficiencies, ranging from 10-15% higher compared to thermally treated felts for both carbon-coated felt (CBGF) and carbonized wasted cloth (CWC) electrodes. There are no signs of degradation after sixty cycles for either material. This significant improvement in energy efficiency signifies a promising advancement in VRFB technology, showcasing its potential for large-scale applications and contributing to enhanced sustainability in energy storage systems.</p>