Donor–Acceptor–Donor-Functionalized Pillared Graphene Oxide for High-Performance Flexible Supercapacitor Device

In this investigation, donor–acceptor–donor (D-A-D) based small organic molecule 2,5-bis((4-aminophenyl) amino) cyclohexa-2,5-diene-1,4-dione (2NH₂-Ph-BQ) as the pillar in between graphene oxide (GO) sheets to fabricate the GO-BAPh-BQ-BAPh-GO electrode materials with graphite foil (GF) substrate is utilized. At first, three-electrode supercapacitor (SC), two-electrode symmetric supercapacitor (SSC) device, and flexible symmetric supercapacitor device using GO-BAPh-BQ-BAPh-GO/GF electrode are assembled, which show excellent electrochemical performance with respective specific capacitance (C_sp), energy density (ED), power density (PD), and cycling stability. The three-electrode cell galvanostatic charging–discharging (GCD) exhibits good C_sp of 338.07 F g⁻¹ at 0.5 A g⁻¹ current density, and cyclic voltammogram exhibits C_sp of 244.31 F g⁻¹ at 5 mV s⁻¹. The SSC device GCD exhibits good C_sp of 147.67 F g⁻¹ at 0.5 A g⁻¹ current density, ED 36.18 Wh kg⁻¹, and PD 1259.98 W kg⁻¹. Cycling stability shows 99.03% retention after 10 000 GCD cycles and coulombic efficiency 99.21%. The performance of the pillared in SSC suggests the great potential of the electrode material or developing both high energy and power densities in electrical energy storage devices.