Two-dimensional covalent organic frameworks based on Ni-Salphen: Preparation and capacitive performance

To develop covalent organic frameworks supercapacitors electrode materials, functional designs is important practical significance to enhance electrochemical performance. Two-dimensional covalent organic frameworks (COFs) based on Ni-Salphen (Ni-Salphen-COF) has been constructed by the reaction of 2,3,6,7,10,11hexaaminotri-phenylene (HATP) and 4,6-dihydroxy-5-methyl-1,3-diformyl benzene (DMDB). Structures, morphology, and electrochemical properties of the Ni-Salphen-COF were characterized via a series of methods. The three-electrode test results suggest that Ni-Salphen-COF showed excellent specific capacitance of 531 F center dot g(-1) and good cycle stability (capacity retention of 89% after 10 000 cycles) at the current density of 1 A center dot g(-1). Meanwhile, Ni-Salphen-COF//AC (AC: activated carbon) in the two-electrode system displayed the specific capacitance of 176 F center dot g(-1) at 1 A center dot g(-1), and the highest energy density was up to 55 Wh center dot kg(-1) at a power density of 900 W center dot kg(-1). Compared to Salphen-COF without Ni, Ni-Salphen-COF showed a high specific capacitance. The electrochemical performance could be attributed to Ni-Salphen units, increasing in electrical conductivity, redox-active, and charge transfer activity.