Surface Oxygen Vacancy Formulated Energy Storage Application: Pseudocapacitor-Battery Trait of W₁₈O₄₉ Nanorods

Porous spherical bundles of W 18 O 49 nanorods with rich oxygen vacancy has been generated by a facile, low cost solvothermal approach and subsequently characterized for energy storage application. The remarkable electrochemical activity of W 18 O 49 nanostructure is referred to the development of oxygen vacancy and nanostructure network leading to maximize the active sites and surface area for the electrolyte ions. A specific capacity of 470 mA h /g at scan rate of 1mV/s and 452 mA h /g at a very high current density of 1.25 A/g were calculated in 1M H 2 SO 4 electrolyte. The experimental results revealed that surface oxygen vacancy enhances the adsorption and reaction site for electrolyte ions indicating the good electrochemical activity of the W 18 O 49 nanostructure materials. GCD summarizes an intermediate mechanism of pseudocapacitor–battery for W 18 O 49 nanorods. These findings will have a profound effect on understanding and mechanism of the surface induced vacancy to the process of electrochemical activity in terms of energy storage.