Hexagonal tungsten oxide-polyaniline hybrid electrodes for high-performance energy storage

Abstract

Progress toward the development of advanced supercapacitor technologies is closely associated with the continuous evolution of nanostructured electrode materials. Herein, work is described in which an inner/outer layer nanostructured hexagonal tungsten oxide (h-WO3)-polyaniline (PANI) hybrid nanomaterial has been elaborately designed and synthesized by a hydrothermal-electrodeposition method. The surface morphology, molecular structure, crystal phase, and chemical composition of the hybrid nanomaterial were studied by FESEM (EDX), FTIR, XRD (SXRD), TEM, and XPS. The resulting WO3-PANI hybrid exhibits a significantly enhanced gravimetric specific capacitance (278 F/g at a current density of 1 A/g) with an outstanding areal specific capacitance of 979 mF/cm2, good rate performance (77.2% capacitance retention from 0.5 to 10 A/g), and stable cycling performance (91.9% capacitance retention over 1500 cycles). The outstanding electrochemical properties of the WO3-PANI electrode are ascribed to its ingenious nanostructure design and the synergistic effects of each component. The symmetric supercapacitors based on WO3-PANI electrodes show a high areal capacitance and remarkable flexibility, suggesting potential application in flexible energy storage devices. Based on analysis and study the band structure and the electrochemical properties of the PANI-coated WO3 hybrid electrode, a possible mechanism for the synergistic effects was proposed in a new perspective.