Solid-type supercapacitor of reduced graphene oxide-metal organic framework composite coated on carbon fiber paper

A composite material of reduced graphene oxide (rGO) and Hong Kong University of Science and Technology-1 (HKUST-1) metal organic framework (MOF) was produced and used as the supercapacitor electrode material. Pure HKUST-1 has a microporous structure with poor conductivity limiting its electrochemical applications while loading rGO to HKUST-1 leads to a novel composite with a mesoporous structure and good electrochemical properties. 10 wt.% rGO/HKUST-1 has a high BET surface area of 1241 m2 g−1, a specific pore volume of 0.78 cm3 g−1, and an average pore diameter of 8.2 nm, which is a proper pore size to allow uptaking and releasing of electrolytes. A half-cell electrode of 10 wt.% rGO/HKUST-1 coated on flexible carbon fiber paper (CFP) exhibits a high specific capacitance of 385 F g−1 at 1 A g−1 while pure HKUST-1 stores only 0.5 F g−1. A 1.8″ × 4.0″ symmetric solid-type supercapacitor of the 10 wt.%rGO/HKUST-1 exhibits a specific power of 3100 W kg−1 and a specific energy of 42 Wh kg−1. The supercapacitor can practically supply electricity to a spinning 3-V motor over 9-min discharging time.