Metal-ion inserted vanadium oxide nanoribbons as high-performance cathodes for aqueous zinc-ion batteries

The current energy and environmental crises are driving the burgeoning demand for efficient and reliable energy storage devices. Aqueous zinc-ion batteries (ZIBs) are currently considered to be promising candidates because of their excellent safety in operation and low cost. However, the real-world application of ZIBs has been impeded by a lack of cost effective cathode materials with the requisite high capacities and stability. Here we report the preparation and relevant properties of a special class of layered materials, which can be described as metal ion-inserted vanadium oxide (MVO, M = Zn, K, Na, and Ca) nanoribbons, as cathode materials for ZIBs. Metal ions are inserted into vanadium oxide by mixing the respective metal chloride with V2O5 particles in aqueous solution at room temperature, resulting in layered MVOs with expanded interlayer spaces. When used as the cathode material for ZIBs, ZnVO nanoribbons delivered specific capacities of 414.8, 368.6, 318.2, 271.2, 225.8 and 163.5 mAh g−1 at current rates of 0.1, 0.2, 0.5, 1, 2 and 5 A g−1, respectively. Also, a capacity of 409.6 mAh g−1 was retained after current rate was returned to 0.1 A g−1. After cycling at 2 A g−1 for 1500 cycles, 84.4% of the initial capacity was retained, much higher than that possible using pristine V2O5. The synthesis strategy can be easily scaled up to a 10-liter reaction scale, demonstrating its potential for the large scale production of cathode materials for high-performance aqueous ZIBs.