{'fraction_non_alphanumeric': 0.0315203955500618, 'fraction_numerical': 0.01792336217552534, 'mean_word_length': 5.476, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Enhanced electrocatalytic performance of nitrogen‐ and phosphorous‐functionalized carbon felt electrode for VO2+/VO2+ redox reaction

Carbon felt co‐doped with nitrogen and phosphorus is suggested as an electrode for catalytically enhancing the redox reaction of the VO2+/VO2+ 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 VO2+/VO2+ 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.