Three-dimensional flexible carbon electrode for symmetrical supercapacitors

• 3D porous AC with galore micro/macropores was fabricated.
• The macropores facilitate the CNTs and rGO into the structure.
• The composite with CNTs, rGO and AC shows good flexibility.
• The assembled symmetrical capacitor delivers high capacitance and good cycling stability.

Three-dimensional (3D) porous active carbon (AC) is fabricated by pyrolysis, pre-carbonization, and alkali activation of the biomass of pomelo peels (PP). The PP-derived AC has abundant micro/meso/macropores boosting a large specific surface area of 1665 m2 g−1 and facilitating incorporation of the carbon nanotubes (CNTs) and reduced graphene oxide (rGO) into the materials. After mixing with CNTs and rGO, the hybrid carbon film with 80 wt% AC (AC/rGO/CNT) exhibits a large capacitance of 214 F g−1 at 1 A g−1, good rate capability, as well as excellent mechanical properties. The specific capacitance of the assembled symmetrical capacitor comprising the hybrid carbon film is 101.5 F g−1 at 1 A g−1 and in conjunction with the superior cycling stability, the high-performance flexible carbon-based supercapacitors (SCs) have large commercial potential.