An Ultrafast Supercapacitor Based on 3D Ordered Porous Graphene Film with AC Line Filtering Performance

A filtering capacitor is an important component for signal stabilization in renewable power generators. Portable ultrahigh-rate electrochemical capacitors with high area specific capacitance have been explored as having the most potential for substitutions to traditional filtering capacitors. Herein, an electrochemical capacitor for AC line filtering is made of 3D graphene film with a highly oriented porous structure by filtering the unique reduced graphene oxide dispersion. The porous structure provides ion accessible sites and the ordered construction improves the ion mobility and the electron transport pathways. As a result, 3D-oriented and porous structure graphene-film-based electrochemical capacitors deliver ultrahigh scan rates of 2000 V s^–1, a fast response with a resistor–capacitor time constant less than 1 ms, and the highest area specific capacitance of up to 755 μF cm^–2 for the devices based on graphene materials at 120 Hz. Furthermore, a deep understanding of the ultrahigh scan rate charge transfer mechanism has been achieved, and it may be the guidance for enhancing AC line filtering performance.