Customizing Hydrophilic Terminations for V₂CT_x MXene Toward Superior Hybrid‐Ion Storage in Aqueous Zinc Batteries

Abstract V₂CT_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 V₂CT_x generally result in high hydrophobicity, poor Zn affinity, and sluggish ion‐diffusion kinetics. Herein, a novel OH‐termination‐rich V₂CT_x material with interlayer “K⁺‐pillars” (alk‐V₂CT_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‐V₂CT_x cathode enables highly reversible and rapid Li⁺/Zn²⁺ co‐insertion/extraction electrochemistry in the formulated 15 m LiTSFI + 1 m Zn(CF₃SO₃)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‐V₂CT_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.