Porous spherical bundles of W18O49 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 W18O49 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 H2SO4 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 W18O49 nanostructure materials. GCD summarizes an intermediate mechanism of pseudocapacitor-battery for W18O49 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. (C) 2019 The Electrochemical Society.