Inorganic–Organic Co‐Intercalated [Al 0.16 (C 5 H 14 ON) 0.12 ]V 2 O 5 ·0.39H 2 O Cathode for High‐Performance Aqueous Zinc‐Ion Batteries

Vanadium oxides hold great promise for aqueous zinc‐ion batteries (AZIBs) due to their multiple oxidation states, diverse crystalline structures, and high vanadium abundance. However, their applications are limited by narrow interlayer spacing, poor reversibility, and high solubility. To address these issues, an inorganic–organic co‐intercalated [Al 0.16 (C 5 H 14 ON) 0.12 ]V 2 O 5 ·0.39H 2 O cathode (IO‐V 2 O 5 ) is reported with enlarged interlayer spacing (13.7 Å) and enhanced structure stability for better AZIBs. Serving as structural pillars, Al 3+ , and betaine create a fast 2D channel for Zn 2+ transport. The positively charged quaternary ammonium groups in betaine strongly interact with the lattice oxygen of V 2 O 5 , further stabilizing the layered structure. The polar carboxylic acid groups weaken the interaction between Zn 2+ and V─O bonds and thus improve Zn 2+ diffusion kinetics with lowered energy barriers. Consequently, IO‐V 2 O 5 cathode delivers high specific capacity (549.5 mAh g −1 at 0.2 A g −1 ), fast ion diffusion rate (10 −8 ∼10 −7 cm 2 s −1 ), superior cycle life (80.1% capacity retention after 20,000 cycles at 30 A g −1 ), and ultrahigh energy density (416.3 Wh kg −1 ), becoming the state‐of‐the‐art systems in comprehensive metrics. This study provides a promising direction to design inorganic–organic co‐intercalated vanadium‐based cathode materials for advanced AZIBs.