Two-Dimensional VO 2 Nanosheets with a Controllable Crystalline-Preferred Orientation for High-Performance Zinc-Ion Batteries.

Due to the environmental friendliness, cost-effectiveness and inherent safety, rechargeable aqueous zinc ion batteries have attracted much interest as a promising energy storage device. VO₂ is one of the most common materials for rechargeable zinc ion batteries. The insertion/extraction of zinc ions within VO₂ is highly anisotropic, with different channel sizes along different axes. Therefore, it is quite important to control the orientation of VO₂ crystals so as to manipulate the transportation of Zn²⁺ ions more effectively and sufficiently. Herein, a novel intercalation-type two-dimensional VO₂ nanosheet with preferred orientation (PO-VO₂) of the c-axis was prepared. Benefitting from the structural merits, the PO-VO₂ nanosheets demonstrate an attractive capacity of 511.6 mAh g⁻¹ at a current density of 0.05 A g⁻¹ in a voltage of 0.2–1.6 V, which is obviously better than that of many vanadium oxide-based cathodes reported until now. The PO-VO₂//Zn aqueous zinc ion full cell exhibits a high energy density of 290.5 Wh kg⁻¹ at a power density of 38.4 W kg⁻¹ (based on the mass of the VO₂ cathode electrode). The outstanding energy storage behavior, together with the facile and affordable synthesis route, endows the PO-VO₂ nanosheets with promising applications for aqueous zinc ion batteries. [ABSTRACT FROM AUTHOR]