Carbon cloth modified by direct growth of nitrogen-doped carbon nanofibers and its utilization as electrode for zero gap flow batteries

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2024-02, Vol.481, p.148644, Article 148644
• Main Authors: Jang, Jooyoung, Shin, Mingyu, Kwon, Yongchai, Jo, Changshin
• Format: Article
• Language: English
• Subjects: Carbon cloth; Carbon nanofiber; Melamine; Solid-to-gas pyrolysis; Zero-gap vanadium flow battery system
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2024.148644

[Display omitted] •N-doped CNFs are grown directly onto CC (NCC) through solid-to-gas pyrolysis of melamine.•Long N-doped CNFs enhance CC's fiber connectivity by intertwining with neighbors.•N-rich functional groups in NCC enhance electrode–electrolyte wettability.•NCC shows a 40-fold increase in electric double-layer capacitance compared to CC.•NCC, reducing charge transfer resistance, showed improved performance in VRFBs. The synthetic procedure and characterization of carbon nanofibers (CNFs) grown on carbon cloth (CC) are explored in this study, with a focus on their potential application as electrodes in vanadium redox flow batteries (VRFBs). CC offers an attractive platform for surface modification owing to its conductive properties and three-dimensional architecture, while the N-doped CNFs formed by nitrogen (N) rich composition of melamine precursor enhance wettability of electrolyte and redox reactivity of vanadium ions. Electrochemical assessments reveal that NCC electrodes significantly increase voltage efficiency (VE) and capacity retention in VRFBs compared to bare CC (BCC) electrodes. Notably, NCC demonstrates a VE of 65.9%, surpassing the 55.9% of BCC electrodes. Additionally, NCC maintains superior capacity retention under varying current densities, a crucial factor for VRFBs. Long-term stability tests over 1000 cycles highlight the NCC electrode's durability, with only a minimal decrease in VE. Post-experiment analysis confirms the structural integrity of the CNFs on the CC electrodes, validating their resilience in VRFB operations. In summary, the study introduces a novel approach for fabricating N-doped CNFs on CC, resulting in electrodes that significantly boost VRFB performance in terms of efficiency, capacity retention, and stability, marking a notable advancement in flow battery technology.