Enhanced supercapacitor performance using EG@COF: a layered porous composite

Abstract

In this work, to address the issue of poor conductivity in COFs, a layered porous composite (EG@COF) was successfully synthesized. A redox-active COF (DAAQ-TFP COF) was grown on the surface of expanded graphite (EG) through a solvent-free in situ synthesis. SEM analysis displayed that the obtained composite (EG@COF) possessed a layered porous structure. Further investigations revealed that EG not only improved electrical conductivity but also regulated the pore size of the COFs. This structure was highly conducive to enhancing the specific capacitance of the electrode material. An electrochemical study demonstrated that the specific capacitance of EG@COF-3 reached 351 C g⁻¹ at 1 A g⁻¹, with 94.4% capacitance retention after 10 000 cycles. The excellent capacitance retention was attributed to the stable backbone of the COF. Meanwhile, an asymmetric supercapacitor (ACS) comprising activated carbon (AC) and EG@COF exhibited an energy density of 16.4 W h kg⁻¹ at a power density of 806.0 W kg⁻¹.