Bimetallic MOF-derived MnCo@C electrodes for high performance vanadium flow batteries

The vanadium flow battery (VFB) has garnered significant attention for its potential to enable cost-effective utilization in large-scale energy storage. Nevertheless, the electrochemical activity of electrodes is limited during vanadium redox reactions, which poses a challenge to achieving high-performance VFBs. To address this, we synthesize a catalyst consisting of amorphous carbon, manganese oxide, and cobalt, to enhance VFB performance. Initially, bimetallic metal-organic frameworks with varying Mn Co ratios are synthesized using a hydrothermal method. Subsequently, the bimetallic metal-organic frameworks are carbonized to form the catalysts. The morphology, composition, electrocatalytic activity, and charging-discharging behavior of the prepared catalysts are then systematically investigated. This paper reveals that: i) the composite with a molar ratio of manganese to cobalt of 1:4, exhibits a uniform and fine particle distribution, an abundance of oxygen-containing functional groups, and exceptional electrochemical activities; ii) it enhances the energy efficiency of VFBs by 9 % compared to those utilizing raw carbon felts and by 5 % over those with mono-MnO@C or mono-Co@C electrodes at 100 mA cm −2 ; iii) it offers significant improvements in terms of operating voltages, cell capacities, high current density characteristics, and lifespan. Consequently, this work introduces a novel electrochemical catalyst for VFBs, enhancing their performance and broadening their potential applications.