Preparation of sandwich-structured V ₆ O ₁₃ via direct current magnetron sputtering for high-capacity zinc-ion batteries

Aqueous zinc-ion batteries are an appealing electrochemical energy storage solution due to their affordability and safety. Significant attention has been focused on vanadium oxide cathode materials for ZIBs, owing to their high specific capacity, unique layered or tunnel structures, and low cost. Compared to traditional methods for preparing and assembling electrode materials, direct current (DC) magnetron sputtering allows direct synthesis and uniform deposition on current collectors, offering advantages such as simplicity, mild reaction conditions, and strong film adhesion. Therefore, we synthesized sandwich-structured vanadium oxides (V₆O₁₃) with a V-O framework on stainless steel using this method, and for the first time, employed them as cathode materials for zinc-ion batteries. The unique crystal structure of V₆O₁₃ features numerous ion diffusion channels, providing ample sites for zinc ion embedding. Additionally, the multiple valence states of vanadium in V₆O₁₃ contribute to its high specific capacity and excellent coulombic efficiency during the charge/discharge process. The V₆O₁₃ synthesized at 400 °C in 3% O₂ exhibits the highest specific capacity (550 mA h g^-1 at 100 mA g^-1). This synthesis strategy demonstrates significant application potential and offers a new pathway for the fabrication of other oxide thin-film electrode materials.