Green-synthesized Ag-doped ZnO Nanocomposites from Rosa canina for High-performance Supercapacitor Electrodes

Abstract

Nowadays, the development of high-performance and sustainable energy storage systems is among the priority research topics. In this context, the efficiency and stability of energy storage devices largely depend on the properties of the electrode materials used. In this work, a silver-doped zinc oxide nanocomposite (ZnO–Ag NP) was synthesized via a green synthesis method using the rich organic components of Rosa canina (RC) fruit. The reducing and stabilizing properties of plant-derived organic constituents enable the environmentally friendly and cost-effective synthesis of ZnO–Ag nanoparticles. The structural and morphological properties of the synthesized nanocomposite were comprehensively characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD) analyses. The analyses revealed that the green-synthesized ZnO–Ag NP formed nanostructures with homogeneous size distribution and exhibited surface functionalization with phytoorganic compounds derived from RC fruit. Electrochemical performance was evaluated using cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS). The ZnO–Ag nanoparticle-modified electrode demonstrated a specific capacitance of 160.04 F·g⁻¹ at a scan rate of 5 mV·s⁻¹, increasing to a maximum of 429.62 F·g⁻¹ at a current density of 0.8 A·g⁻¹ in 1 M NaOH electrolyte. Furthermore, the symmetric device achieved an energy density of 8.16 Wh·kg⁻¹ and a power density of 675.86 W·kg⁻¹. The findings indicated that the ZnO–Ag NP delivers high specific capacitance, favorable energy density, and good power density, making it a promising candidate for supercapacitor applications. In conclusion, the green-synthesized ZnO–Ag NP obtained via RC fruit extract offers significant potential in energy storage technologies as an effective electrode material produced through an environmentally friendly approach.