Silver-tungsten heterostructures nanocomposite for high-performance supercapacitor application

In this study, silver oxide (Ag₂O)-doped tungsten oxides (WO₃) are synthesized via a hydrothermal route and systematically investigated as a potential electrode material for supercapacitor applications. The structural and surface characteristics of the synthesized materials are examined using X-ray diffraction (XRD), UV–Vis spectroscopy, field-emission scanning electron microscopy (FESEM), high-resolution scanning transmission electron microscopy (HRSTEM), and X-ray photoelectron spectroscopy (XPS). Electrochemical performance is evaluated through cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) measurements. The Ag₂O-doped WO₃ electrode exhibits outstanding electrochemical behavior, delivering a high specific capacitance of 1700 F g⁻1 at a current density of 1 A g⁻1. In addition, the electrode demonstrates notable cycling stability, retaining 76% of its initial capacitance after 5000 consecutive charge–discharge cycles. To further assess its practical applicability, an asymmetric supercapacitor (ASC) device is assembled using Ag₂O-doped WO₃ as the positive electrode and reduced graphene oxide (rGO) as the negative electrode. The fabricated ASC delivers an energy density of 15.7 Wh kg⁻1 and a power density of 650 W kg⁻1, indicating its efficient energy-storage capability. Notably, two ASC devices connected in series successfully power a blue light-emitting diode (LED) operating at 2.8 V, demonstrating the practical potential of the developed electrode material.