Bilayered nanostructured V2O5 nH2O xerogel constructed 2D nano-papers for efficient aqueous zinc/magnesium ion storage

Aqueous zinc/magnesium ion batteries (AZIBs/AMIBs) offer a powerful alternative for large-scale energy storage because of their high safety and low cost. Consequently, the design of high-performance cathode materials is essential. In this paper, we present a simple strategy that combines oxygen defect (Od) engineering with a 2D-on-2D homogeneous nanopape-like bilayer V2O5 nH2O Xerogel (BL-HVOd NPS). This strategy employs Od to improve Zn2+/Mg2+insertion/extraction kinetics and reduce irreversible processes for high-performance AZIBs/AMIBs. Interlayer water molecules serve as an effective spacer to stabilize the expanded interlayer gap in BL-HVOd NPS, thereby providing extended diffusion channels for Zn2+/Mg2+ during insertion/extraction. In addition, the interlayer water molecules help shield the electrostatic interaction between Zn2+/Mg2+ and the BL-HVOd NPS lattice, which improves diffusion kinetics during repeated. Electrochemical characterization results indicate that our engineered material can effectively the surface adsorption and internal diffusion of Zn2+/Mg2+. More importantly, the successfully prepared unique 2D-on-2D homogenous nanopaper structure enhances electrolyte/electrode contact and reduces the migration/diffusion path of electrons/Zn2+ and Mg2+, thus greatly improving rate performance. As a result, BL-HVOd NPS as an AZIBs/AMIBs electrode offers a better reversible capacity of 361.8 and 162.8 mAh/g (at 0.2 A/g), respectively, while having an impressively long cycle life. This enlightened design opens up a new way of working with advanced AZIBs/AMIBs high-quality cathode materials.