Pore-Forming Agents Enhancing the Electrochemical Performance of MOF-Derived MnO@C Electrodes for Vanadium Flow Batteries

The electrode is crucial for electrochemical reactions, significantly impacting the vanadium flow battery (VFB) performance. However, their relatively low electrochemical activity remains a major obstacle to developing high-performance VFBs. To overcome this limitation, we introduce a catalyst synthesized by integrating pore-forming agents─specifically, poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) triblock copolymer (P123) and polyoxyethylene–polyoxyethylene–polyoxyethylene triblock copolymer (F127)─into MnO@C derived from a metal–organic framework. This study marks the first application of such an approach to VFB enhancement. A comprehensive analysis is conducted to examine the catalyst’s morphology, composition, electrocatalytic activity, and charge–discharge behavior. The results reveal that (i) the prepared catalysts possess a nanoporous structure with MnO nanoparticles uniformly dispersed in amorphous carbon; (ii) pore-forming agent-modified MnO@C, especially P123–MnO@C, exhibits a large specific surface area, an abundance of oxygen-containing functional groups, and exceptional electrochemical activities; (iii) it enhances the energy efficiency of VFBs by 5.7% compared to those utilizing raw carbon felts and by 5.1% over those with MnO@C electrodes at 100 mA cm–2; and (iv) it significantly improves operating voltages, cell capacities, high current density properties, and cycling performance. Thus, this study proposes an innovative electrochemical catalyst for VFBs, enhancing performance and advancing renewable energy storage solutions.