Construction of proton recognized confined ion conductive channel for high performance vanadium redox flow battery

The precise design of physicochemical microstructure in ion conductive channel is extremely important but challenging to enhance ion transport and selectivity for high performance vanadium redox flow battery. Herein, the proton recognized sulfonated organic covalent framework(SCOF) layer is in-situ growth on the hierarchical pores of polybenzimidazole-based ion conductive membrane, strongly recognizing proton by enhanced electrostatic field intensity in confined sub-2-nm SCOF ionic conductive channel. Much lower proton adsorption energy (-296.96 kJ mol^-1) and 1.65 folds diffusivity comparing to vanadium ions make protons preferentially be recognized during the competitive adsorption between protons and vanadium ions, and substantially accelerate diffuse through channel. Extremely high H⁺/Vⁿ⁺ ion selectivity (3.93×10¹² mS s cm^-1) lead to excellent energy efficiency (80.1 % @340 mA cm^-2) and low discharge capacity decay rate (0.06%/cycle @100 mA cm^-2) in VRFB. The proton recognition SCOF confined layer enhanced hierarchical porous ion conductive channel presents the promising candidate for next generation VRFB.