A study on the effect of phase conversion of tungsten nanostructures on their electrochemical energy storage performance

Herein, we report the synthesis of tungsten based nanostructures such as WO 3 , WO 3− x (W0 2.72 :WS 2 ), and WS 2 through a facile single step hydrothermal technique. The optical, structural, and morphological studies are conducted, and the electrochemical performance of each electrode material is evaluated in a symmetric two electrode configuration. An enhancement in the electrochemical energy storage performance has been observed on changing the phase from WO 3 to WS 2 , which may be due to the accompanying changes in morphology and surface area. At 1 A g −1 , the symmetric supercapacitors with WO 3 , WO 3− x , and WS 2 electrodes exhibit specific capacitance values of 62, 86, and 215 F g −1 , respectively. At a power density of 0.76 kW kg −1 , the WO 3 , WO 3− x and WS 2 based devices offer energy density values of 5.5, 7.6, and 19.1 W h kg −1 , respectively. The WS 2 electrode based supercapacitor retains an excellent cycling stability rate of 97% over 10 000 continuous charge discharge cycles. .Herein, we report the synthesis of tungsten based nanostructures such as WO 3 , WO 3− x (WO 2.72 : WS 2 ), and WS 2 through a facile single step hydrothermal technique and evaluated their supercapacitor performance for energy storage applications.