A review of ultrafast supercapacitors for AC-line filtering

• Ultrafast supercapacitors offer high power density and fast response, making them promising replacements for bulky aluminum electrolytic capacitors in AC-line filtering. • Electrode materials such as graphene, carbon nanotubes, conductive polymers, and transition metal compounds are key to achieving high-frequency performance. • Electrolyte selection and device configuration (e.g., planar, sandwich) significantly influence the frequency response and overall performance of ultrafast SCs. • Challenges remain in improving energy density and operating voltage, necessitating further research for practical applications.