<p>In this study, an oxidized yttrium/iron tungstate (Y₂O₃/FeWO₄) composite electrode material was successfully synthesized using a solvothermal method. The results indicate that the incorporation of Y₂O₃ significantly improves the electrical conductivity and charge transfer rate of FeWO₄. Additionally, the porous structure increases both the specific surface area and pore volume, offering more pathways for ion transport. This enhancement leads to a faster electrochemical reaction rate and improved cycle stability. In a three-electrode test, the Y₂O₃/FeWO₄ composite exhibited a high specific capacitance of 1662 F/g at a current density of 1 A/g. Even at a high current density of 15 A/g, it maintained a capacitance of 1028 F/g. Cycle performance tests showed excellent durability, with a capacitance retention rate of 98.5% after 10,000 cycles at 1 A/g. Furthermore, an asymmetric supercapacitor (ASC) assembled using Y₂O₃/FeWO₄ as the positive electrode and carbon nanotubes (CNTs) as the negative electrode demonstrated an energy density of 46.53 Wh/kg at 1 A/g. After 10,000 cycles at the same current density, it retained 94.3% of its capacitance, confirming its outstanding energy density and long-term stability.</p>