Fabrication of Pyridinic Nitrogen‐Functionalized Carbon Cloth for High‐Performance Iron‐Chromium Flow Batteries

ABSTRACT The iron‐chromium flow battery (ICRFB) is a promising large‐scale energy storage technology; however, its performance is largely limited by the sluggish Cr(II)/Cr(III) redox kinetics arising from poor carbon electrode‐electrolyte interfacial compatibility. Herein, we propose a targeted doping strategy that utilizes an eco‐friendly urea precursor to construct a pyridinic nitrogen‐rich carbon cloth electrode via a facile impregnation–calcination process. Density functional theory (DFT) calculations reveal that the pyridinic‐N configuration strengthens the adsorption of Cr(H 2 O) 5 Cl 2 + , reduces charge transfer resistance, thereby improving the reaction kinetics. Soft X‐ray absorption near‐edge structure (XANES) and X‐ray photoelectron spectroscopy (XPS) analyses further confirm the successful incorporation of pyridinic nitrogen into the carbon lattice, forming electron‐rich active centers that optimize the surface charge distribution and chemisorption behavior. The optimized electrode delivers a high discharge capacity of 689.3 mAh and maintains an energy efficiency of 72.83% at 200 mA cm −2 , together with exceptional cycling stability over 500 cycles at 140 mA cm −2 . This work offers a new pathway for precursor‐enabled interfacial engineering, bridging molecular design with electrochemical performance optimization in ICRFBs.