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 ${\mathrm{NH}}_4^{+}$ , which effectively improved the Zn²⁺ diffusion kinetics and cycle stability of the electrode. In addition, the binding between ${\mathrm{NH}}_4^{+}$ 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.