Abstract
All-vanadium redox flow batteries (VRFBs), with good operation flexibility and scalability, have been regarded as one of the most competitive substitutes for large-scale energy storage. However, because of the low electrochemical activities of traditional electrodes such as carbon felt and graphite felt, they will impede the interfacial charge transfer processes and decrease the efficiencies of VRFBs. In this work, Co-MOF (ZIF-67) was prepared as a precursor, and a cobalt mixed nitrogen 3D carbon nanostructure and carbon felt (Co-CN@CF) was prepared by chemical reaction and used in VRFBs as electrodes. With the unique structure and high efficiency catalyst on the carbon felt, the Co-CN@CF exhibited excellent electrochemical activity toward the VO2+/VO2+ redox couple in the VRFB, with an average cell voltage efficiency (VE) of 86% and an energy efficiency (EE) of 82% at 80 mA cm−2, which was increased by more than 10% compared with the traditional carbon felt. VRFBs with a Co-CN@CF electrode also showed much better long-term stability (over 1000 cycles) compared with the battery with a pristine CF electrode.
Highlights
With the increasing awareness of energy conservation and environmental protection, it is important to use renewable energy sources such as solar, wind, and hydropower to replace fossil fuels
The results showed that the Co-CN@CF exhibited excellent electrochemical activity toward VO2+/VO2+ redox couples in the vanadium redox flow batteries (VRFBs), with an average cell voltage effi3 of 10 ciency (VE) of 86% and an energy efficiency (EE) of 82% at 80 mA cm−2, which was increased by more than 10% compared with the traditional carbon felt
The precursor ZIF-67 was grown in situ on CF, which was different from the traditional postbonding method
Summary
With the increasing awareness of energy conservation and environmental protection, it is important to use renewable energy sources such as solar, wind, and hydropower to replace fossil fuels. The electrodes, with high electrical conductivity and stability in concentric acid-based vanadium electrolytes, can control the electron transfer and mass transport [19] Materials such as graphite felt (GF), carbon felt (CF), and carbon paper (CP) are promising electrodes for VRFBs, as they are characterized by a low cost and wide range of operating potential. The results showed that the Co-CN@CF exhibited excellent electrochemical activity toward VO2+/VO2+ redox couples in the VRFB, with an average cell voltage effi of 10 ciency (VE) of 86% and an energy efficiency (EE) of 82% at 80 mA cm−2, which was increased by more than 10% compared with the traditional carbon felt.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
