Facile synthesis of self-assembled WO3 nanorods for high-performance electrochemical capacitor

Abstract

Hexagonal WO3 nanorod thin films have been successfully synthesized by a simple hydrothermal method using ammonium sulfate ((NH3)2SO4) as a structure directing agent. The effect of structure directing agent on structural, morphological and electrochemical properties of WO3 thin films is investigated. The nanorods with diameters of 50–200 nm and length up to several micrometers are obtained. The results demonstrate that the concentration of (NH3)2SO4 plays an important role in the growth direction and formation of self-assembled WO3 nanorods. The electrochemical measurements show that WO3 thin films demonstrate excellent electrochemical performance with a maximum specific capacitance of 538 F g−1 at 5 mV s−1, high power performance and good cycling stability (85% over 2000 CV cycles). The present work may provide a facile and versatile approach to tune the morphology and capacitive performance of WO3 thin films required for high-performance energy storage devices.