Customizing Hydrophilic Terminations for V2CTx MXene Toward Superior Hybrid‐Ion Storage in Aqueous Zinc Batteries

Abstract V 2 CT x MXene is a “rising star” cathode material for aqueous zinc‐based batteries (AZBs) owing to its large/flexible interlayer spacing, rich redox chemistry of V, and high electronic conductivity. Nevertheless, the plentiful F surface terminations generated during the common preparation (fluorine‐containing acid etching process) of V 2 CT x generally result in high hydrophobicity, poor Zn affinity, and sluggish ion‐diffusion kinetics. Herein, a novel OH‐termination‐rich V 2 CT x material with interlayer “K + ‐pillars” (alk‐V 2 CT x ) is fabricated via a facile one‐step alkalization method, which features excellent hydrophilicity, expanded ion‐transport channels, and robust layered structure. Impressively, the tailored alk‐V 2 CT x cathode enables highly reversible and rapid Li + /Zn 2+ co‐insertion/extraction electrochemistry in the formulated 15 m LiTSFI + 1 m Zn(CF 3 SO 3 ) 2 aqueous electrolyte, meanwhile, the “self‐exfoliation” phenomenon of MXenes upon cycling significantly increases the active sites, rendering the superior rate performance (498.2/195.1 mAh g −1 at 0.1/30 A g −1 , respectively) and exceptional cycling life (96.2% capacity retention over 20 000 cycles). Systematic in situ/ex situ analyses and theoretical computations elucidate the above hybrid‐ion storage mechanisms. Finally, flexible quasi‐solid‐state rechargeable Zn batteries employing the alk‐V 2 CT x cathode exhibit inspiring energy output even under severe deformation conditions and low temperatures. This study provides new perspectives for designing high‐performance MXene‐based cathodes for AZBs by modulating surface terminations.