One of the most widely explored paths to reduce the cost of electrochemical storage systems is the replacement of current lithium metal with alternative metal anodes having lower cost and higher abundance. Nowadays, the research on aluminium-ion batteries is rapidly gaining momentum because of its various advantages. Aluminium is the most abundant metal in the Earth’s crust with four and seven times larger volumetric capacity compared to lithium and sodium, respectively. Additionally, the three-electron redox reaction (Al⁺³) and the smaller ionic radius (0.0535 nm) of aluminium offers the potential for higher specific energy and power. But, exploring compatible and high-performance cathode materials for rechargeable aluminium ion battery is a key issue.

In this paper, we report the electrochemical performance of V₂O₅ as a cathode material for aluminium ion battery in AlCl₃ aqueous solution. The nanostructure of V₂O₅ was synthesized via hydrothermal synthesis protocol. The preliminary physiochemical characterization of synthesized V₂O₅ was performed using a large number of techniques. The electrochemical properties were investigated by cyclic voltammetry and charge-discharge measurements in 0.5 M AlCl₃ aqueous electrolyte. The V₂O₅ cathode delivered an initial discharge capacity of ~ 140 mAh g^-1 at high current density of 500 mA g^-1 with an excellent capacity retention of 96 % after 1000 cycles at 1 A g^-1, which is among the best cathode performances reported for aqueous AIBs. The high energy storage mechanism of V₂O₅ is based on the facile intercalation and deintercalation of the tri-valent Al⁺³ ions from the electrolyte through the electrode material during discharging and charging processes, respectively. Further, the V₂O₅ cathode fabricated in this work is of low cost and high safety, which can bring a jump in the development of novel aqueous aluminium ion battery.