Ag3O4 grafted NiO nanosheets for high performance supercapacitors

Abstract

Ag₃O₄ grafted NiO nanosheets were successfully synthesized via hydrothermal route. The morphological and structural analysis was performed using scanning transmission electron microscopy (STEM), scanning electron microscopy (SEM) and X-ray diffraction (XRD) studies. The grafting of Ag₃O₄ on NiO nanosheets enhanced the conductivity of the nanosheets and resulted in a maximum specific capacitance of 1504 F g⁻¹ for 5 wt% of Ag on NiO (AGN2) at a scan rate of 3 mV s⁻¹. The porous nature of AGN2 provides larger paths for ions, which significantly increases the intercalation of ions and utilization rate of electrode materials. Galvanostatic charge discharge (GCD) analysis reveals a specific capacitance of 1524 F g⁻¹ for AGN2 at a current density of 1 A g⁻¹ with excellent cyclic stability (12% loss after 1500 cycles). An asymmetric supercapacitor device (AGN2//RGO) achieved a specific capacitance of 274 F g⁻¹ with an energy density of 37 Wh kg⁻¹ and the power density of 499 W kg⁻¹ at a discharge current of 0.2 A g⁻¹.