Enhanced performance of electrical double-layer capacitor by controlling the specific surface area and pore structure of ZIF-67

Abstract Electrical double-layer capacitance can be enhanced through the development of carbon materials possessing elevated specific surface area, porosity, and electrical conductivity. In this study, we demonstrate a facile approach to synthesizing carbon materials with a meticulously controlled pore structure of ZIF-67 by precise manipulation of the precursor solution quantities. The concentration of the precursor affects the crystal sizes of ZIF-67 due to the different nucleation rates. After the carbonization of the crystals, smaller cobalt nanoparticles formed within the carbon materials derived from the ZIF-67 crystal with larger dimensions. Removal of the nanoparticles by acid treatment induced the formation of porous carbon, resulting in the enhanced performance of electrical double-layer capacitors. The nanoporous carbon, derived from the largest-sized ZIF-67 template, exhibited a remarkable specific capacitance of 157 F/g at a current density of 1 A/g, retaining an impressive 85% of this value after 30,000 charging/discharging cycles at 16 A/g.