Stable structure and oxygen-rich vacancy assist NH4V4O10 to become a high-performance aqueous zinc-ion battery cathode material

Ammonium vanadate (NH4V4O10) is an emerging cathode material for aqueous zinc-ion batteries (AZIBs), gaining recognition for V element multivalent and budget. However, Zn2 + exhibit robust coulombic bonds with the lattice structure, poor ion transport and cycling stability, and narrow layer spacing limit its further application. In this study, we prepared an efficient cathode designed for AZIBs by inserting ascorbic acid (AA) into the interlayer of NH4V4O10 (AANVO). The insertion of AA increases the distance between layers and enhances the stability of the material's structure, provided a large interlayer channel for the diffusion of Zn2+ and successfully partially replaced NH4+ in NH4V4O10, alleviating the irreversible deamination reaction. Furthermore, the doping of AA reduces the crystallinity of NVO, increases the oxygen vacancies, and accelerates the ion and charge transfer kinetics, resulting in excellent electrochemical properties. The findings reveal that AANVO exhibits a remarkable charge capacity of 638 mAh g- 1 at 0.1 A g-1, and it maintains 86.6 % of this capacity after 1000 cycles when subjected to 10 A g-1.