There are four kinds of vanadium oxides in monovalence vanadium oxides, which are VO, V2O3, VO2, and V2O5, respectively. Due to the instability of VO at room temperature, the applications of VO in energy storage and electrocatalysis were not found. So in this section, the V2O3, VO2, and V2O5would be. As one of the most common vanadium oxides, the V2O5 was applied in alkali metal-ion batteries [18,19,20], zinc-ion batteries (ZIB) [21,22,23],. Zhang et al. grew a V2O5 nanosheet array on carbon fiber and applied it to the anode material of sodium-ion batteries. The specific capacity was 241. In terms of the application of V2O5 in lithium-ion batteries cathode materials, the common strategy is to synthesize the special morphology to improve the Li+ storage performance by interface effects. For example, Mai et al. prepare V2O5 nanofiber with a length of. VO2 is a commonly used phase transition function material; the most famous one is rutile VO2(R) which transforms into monoclinic VO2(M) at 68 °C. The monoclinic VO2(M) is metallic and has various properties, such as a smart device, terahertz active materials.
