Fluorine-Driven Interfacial Reconfiguration for pH-Universal CO2 Electrolysis at High Current Densities via Enhanced CO2 Enrichment and Proton Feeding.

High-rate CO2 electroreduction is challenged by the conflict between sluggish CO2 activation and hydrogen evolution at high currents, particularly under pH-universal and dilute CO2 conditions. In this study, a defective fluorine-modified bismuth (F-Bi) with electron-rich surface was generated by electrochemical reconstruction of fluorine-doped bismuth oxide (F-Bi2O3), which exhibits a formate/formic acid Faradaic efficiency (FEHCOO - /HCOOH) approaching 100% at 1800 mA cm-2 under pH-universal conditions. In a membrane electrode assembly (MEA), F-Bi delivers a FEHCOO - of 95.2% at 3.6 V and sustains operation for 120 h at a total current of 1 A. It also maintains a FEHCOO - above 95% at 800-1200 mA cm-2 under a dilute CO2 feed of 15 vol% CO2/N2. In situ spectroscopy and ab initio molecular dynamics (AIMD) reveal that surface F species serve as hydrogen-bond acceptors that reconfigure the interfacial water network, enhancing K+ enrichment, local alkalinity, CO2 accumulation, and rapid proton transfer. Density functional theory (DFT) further indicates that F-Bi surface, combined with the K+/H2O microenvironment, facilitates charge redistribution, enhances *CO2 and *OCHO adsorption, and then lowers the reaction energy barrier. This work overcomes the intrinsic activity-selectivity trade-off in CO2 electrolysis, offering a promising strategy for designing high-performance pH-universal electrocatalysts.