Morus alba-mediated defect-rich Fe-doped V2O5 nanoparticles on woven carbon fiber for high-performance supercapacitor with enhanced charge storage mechanism

The depletion of fossil fuels and the growing demand for sustainable energy solutions have accelerated research into advanced energy storage technologies. Supercapacitors have gained prominence due to their remarkable power density, rapid charging capabilities, and extended cycle life, making them ideal candidates for addressing energy challenges. Vanadium oxide (V2O5), known for its versatile valence states, affordability, low toxicity, and broad voltage window, has emerged as a promising material for energy storage applications. This study presents a green synthesis approach to prepare pristine V2O5 and Fe-doped V2O5 (V1.9Fe0.1O5, V1.8Fe0.2O5, and V1.7Fe0.3O5) using Morus alba (mulberry) leaf extract as a natural reducing and stabilizing agent. This ecofriendly method offers a sustainable alternative to conventional synthesis routes while optimizing Fe doping to enhance the electrochemical performance of V2O5-based electrodes. The results revealed that Fe doping plays a crucial role in improving redox activity and maintaining the structural stability of the V2O5 lattice. Among the synthesized materials, V1.8Fe0.2O5 exhibited superior performance, achieving a specific capacitance of 719.25 F/ g at a current density of 2 A/g in a 1 M Na2SO4 electrolyte. This performance surpassed that of undoped V2O5 (604.17 F/g), V1.9Fe0.1O5 (647.32 F/g), and V1.7Fe0.3O5 (676.09 F/g), demonstrating the significance of optimized Fe content in balancing redox activity and structural integrity. Furthermore, a symmetric supercapacitor device fabricated with V1.8Fe0.2O5 delivered exceptional cycling stability, retaining 94 % of its initial capacitance after 10,000 cycles, and achieved an energy density of 49 Wh/kg at a power density of 957 W/kg. These findings underscore the potential of Fe-doped V2O5 as a highly efficient electrode material for next-generation super- capacitors, offering a sustainable and scalable solution to meet rising energy storage demands.