Pyrene-based covalent organic polymers with nano carbonaceous composites for efficient supercapacitive energy storage

Abstract

Covalent organic polymers (COPs) show great potential as supercapacitor electrodes due to their tunable properties, stability, and high capacitance. In this work, we prepared a covalent organic polymer (Py-DSDA-COP) through a Schiff base reaction of the 1,3,6,8-tetrakis(4-formylphenyl)pyrene monomer (Py-Ph-CHO) and 4,4′-disulfanediyldianiline (DSDA), validated its chemical structure, and investigated its thermal stability, porosity, morphology, and electrochemical properties. The Py-DSDA-COP displayed high semi-crystallinity, good porosity, and a specific capacitance of 56.18 F g⁻¹. To improve its electrochemical performance, we incorporated different nano-carbonaceous materials [fullerene (C60), MWCNTs, and SWCNTs] into Py-DSDA-COP and compared their characteristics. The Py-DSDA-COP/SWCNTs showed the highest specific capacitance (171 F g⁻¹) at 1 A g⁻¹and highest energy density (23.7 W h kg⁻¹) with a capacity retention of 93% after 2000 cycles, which is superior to those of Py-DSDA-COP/MWCNTs and Py-DSDA-COP/C60 nanocomposites. These superior electrochemical characteristics of Py-DSDA-COP/SWCNTs are attributed to the excellent π–π stacking interactions, higher EDLC behavior, higher conductivity, lower diameter, and higher surface area of SWCNTs than those of MWCNTs.