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Enhanced electrocatalytic performance of nitrogen‐ and phosphorous‐functionalized carbon felt electrode for VO 2 + / VO 2 + redox reaction
Author(s) -
Park Seoung Eun,
Lee Kyubin,
Suharto Yustian,
Kim Ki Jae
Publication year - 2021
Publication title -
international journal of energy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.808
H-Index - 95
eISSN - 1099-114X
pISSN - 0363-907X
DOI - 10.1002/er.5856
Subject(s) - redox , electrochemistry , inorganic chemistry , vanadium , chemistry , carbon fibers , electrode , x ray photoelectron spectroscopy , nitrogen , materials science , chemical engineering , organic chemistry , composite number , composite material , engineering
Summary Carbon felt co‐doped with nitrogen and phosphorus is suggested as an electrode for catalytically enhancing the redox reaction of the VO 2+ /VO 2 + redox couple. N and P can be simultaneously incorporated with the carbon felt via a one‐step facile synthesis method using aniline and triphenylphosphine as the N and P sources. Successful co‐doping is confirmed using energy‐dispersive spectroscopy and X‐ray photoelectron spectroscopy analyses. The electrochemical activity of the proposed carbon felt electrode toward the VO 2+ /VO 2 + redox reaction is significantly enhanced when compared to those of carbon felt electrodes doped with only nitrogen or phosphorus, owing to the synergetic effect of the N, P co‐doping. The all‐vanadium redox flow battery (VRFB) assembled with the N, P co‐doped carbon felt (NPCF) electrode exhibits a highly stable cyclic performance accompanied by considerably improved energy efficiencies of 84.94% and 84.33% in the 1st and 50th cycles, respectively. In addition, the cell employing the NPCF electrode exhibits an energy efficiency of 79.1%, approximately 11% higher than that of bare carbon felt (BCF: 68.1%), at a high current density of 100 mA cm −2 . This improvement is mainly attributed to abundant electrochemical active sites for the oxidation and reduction of vanadium ions provided by the N and P functional groups formed on the carbon felt via our proposed treatment. These mitigate electrochemical polarization and accelerate the redox reaction.