Uniformly distributed FeVO₄ nanocuboids on exfoliated rGO facilitated by supersonic spraying for wearable supercapacitors

High-energy–density supercapacitors exhibiting high power density and long-term stability are essential devices for energy storage applications, such as wearable electronics. In this study, we utilized supersonic spray deposition to exfoliate reduced graphene oxide (rGO). Additionally, a solvothermal process was employed to engineer the nanostructure of iron/vanadium oxides. Consequently, the resulting multivalent iron/vanadium oxide and rGO composites exhibited remarkably high energy densities. Three major parametric studies were conducted to investigate the electrochemical properties of iron oxide (FO), vanadium oxide (VO), and iron/vanadium oxide (FVO) composites with rGO. FVO/rGO emerged as the most promising sample, exhibiting an areal capacitance of 1240 mF·cm⁻² at a current density of 2 mA·cm⁻², as well as achieving a 90 % capacitance retention even after 8000 galvanostatic charge–discharge cycles. Furthermore, this sample delivered an energy density of 0.17 mWh·cm⁻² at a power density of 4 mW·cm⁻².