One-Step Hydrothermal Synthesis of NVO Cathodes with Varied Lattice NH₄ ⁺ Content: Effect on Structural Evolution and...

Aqueous zinc ion batteries have been extensively researched due to their distinctive advantages such as low cost and high safety. Vanadium oxides are important cathode materials, however, poor cycle life caused by vanadium dissolution limits their application. Recent studies show that the lattice NH₄ ⁺ in vanadium oxides can act as a pillar to enhance structural stability and play a crucial role in improving its cycling stability. Nevertheless, there is still a lack of research on the effect of the lattice NH₄ ⁺ content on structural evolution and electrochemical performance. Herein, we synthesize vanadium oxides with different contents of lattice NH₄ ⁺ by a one-step hydrothermal reaction. The vanadium oxides with lattice NH₄ ⁺ exhibit high initial capacity, as well as good cycling stability and rate performance compared to bare vanadium oxide. Combined with electrochemical analyses, ex-situ structural characterizations, and in-situ X-ray diffraction tests, we reveal that the lattice NH₄ ⁺ content plays a positive role in vanadium oxides' structural stability and cation diffusion kinetics. This work presents a direction for designing high-performance vanadium cathodes for aqueous zinc ion batteries.