Self-Assembled rGO-Integrated Cd-MOF as a High-Stability Electrode for Advanced Symmetric and Asymmetric Supercapacitors

The tailoring and controlled fabrication of a metal-organic framework (MOF) with diverse conductive materials have garnered significant academic attention, owing to their potential applications in next-generation energy storage devices. Herein, we synthesized the rGO@Cd-MOF composite by a facile solvothermal method and used it as an electrode in a hybrid supercapacitor. FESEM and TEM images verify composite material formation, as Cd-MOF crystals are dispersed on the rGO nanosheet. The rGO@Cd-MOF composite electrode showcases outstanding electrochemical performance in a 3-electrode system by achieving a high specific capacity of 634 C g-1 at a current density of 2 A g-1 within the potential range of 0 to 0.6 V. Furthermore, the composite was utilized as an electrode in symmetric and asymmetric supercapacitor devices; however, the ASC device achieved an impressive energy density of 78.69 Wh kg-1 at a power density of 1282 W kg-1, compared to the SSC device, which achieved 21.15 Wh kg-1 at 721 W kg-1. The ASC device maintained 90% Coulombic efficiency and 94% capacity after 10k charge-discharge cycles. Thus, for the first time, this study presents the use of the rGO@Cd-MOF composite to develop an effective supercapacitor electrode. This proposed layout is also versatile for flexible symmetric and asymmetric supercapacitor devices, providing high energy density and specific capacity values.