Two-Dimensional V₂O₅ Nanosheets as an Advanced Cathode Material for Realizing Low-Cost Aqueous Aluminum-Ion Batteries

Aluminum-ion batteries (AIBs) show tremendous promise and advantages, which make them useful for both grid and off-grid energy storage applications. In this paper, an interconnected sheet-like morphology of low-cost V 2 O 5 is reported as a cathode material to improve the capacity, rate capability, and cycling stability of AIBs. The V 2 O 5 -based cathode is able to deliver an initial discharge capacity of ∼140 mA h g –1, at a high current density of 0.5 A 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 fast intercalation and deintercalation of Al 3+ between the stacked layers of V 2 O 5 help in ensuring such high-performance characteristics. Notably, the smaller lattice expansion (∼1.4%) of V 2 O 5 indicates that the expansion and contraction of the crystal structure occur reversibly during the charge–discharge process. The stability of the material is established by analyzing the X-ray diffraction patterns of the material after cycling. Such studies have remained ignored in AIBs till date.