Ion‐Molecule Co‐Confining Ammonium Vanadate Cathode for High‐Performance Aqueous Zinc‐Ion Batteries

Vanadium-based cathode materials have attracted great attention in aqueous zinc-ion batteries (AZIBs). However, the inferior ion transport and cyclic stability due to the strong Coulomb interaction between Zn2+ and the lattice limit their further application. In this work, CO2 molecules are in situ embedded in the interlayer structure of NH4 V4 O10 by decomposing excess H2 C2 O4 ·2H2 O in the main framework, obtaining an ion-molecule co-confining NH4 V4 O10 for AZIB cathode material. The introduced CO2 molecules expanded the interlayer spacing of NH4 V4 O10 , broadened the diffusion channel of Zn2+ , and stabilized the structure of NH4 V4 O10 as the interlayer pillars together with NH4+${\mathrm{NH}}_4^ + $ , which effectively improved the Zn2+ diffusion kinetics and cycle stability of the electrode. In addition, the binding between NH4+${\mathrm{NH}}_4^ + $ and the host framework is stabilized via hydrogen bonds with CO2 molecules. NVO-CO2 -0.8 exhibited excellent specific capacity (451.1 mAh g-1 at 2 A g-1 ), cycle stability (214.0 mAh g-1 at 10 A g-1 after 1000 cycles) and rate performance. This work provides new ideas and approaches for optimizing vanadium-based materials with high-performance AZIBs.