High-Energy Supercapacitor Constructed by Cerium-Doped Iron Tungstate Cathode Materials with Oxygen Vacancies and Hydrophilic Carbon Nanotube Anode

To address the worsening energy crisis from rapid fossil fuel consumption, this study synthesized Ce-FeWO4 composites and hydrophilic carbon nanotubes. XRD and other characterizations showed all intermediates had rough, porous nanosheet morphology; Ce-doping formed disordered porous structure in FeWO4, increasing its specific surface area. Three-electrode tests confirmed optimal parameters: 0.5% Ce-doping and 12 h growth. Ce-FeWO4 exhibited a specific capacity of 1875 ± 28 F/g at 1 A/g (based on five parallel samples), and retained 1807 F/g after 3000 cycles (exceeding previous studies) with excellent stability. The Ce-FeWO4//CNTs asymmetric supercapacitor achieved 152 F/g specific capacity, 81.4 Wh/g energy density, and 768 W/kg power density. The simple, efficient, eco-friendly preparation process and the material’s high capacitance and stability offer broad application prospects in the electrode field.