Synergistic Cobalt-MOF@rGO Nanocomposites for High-Performance Supercapacitors and Electrochemical Detection of Cd2+ ions

Abstract

Metal-organic frameworks (MOFs) and Carbon-based nanocomposites are becoming more and more attractive porous materials for electrode fabrication to store the electrochemical energy because of their improved electrical conductivity, substantial theoretical capacitance, and diverse range of applications. Given this, a new pseudocapacitive binary nanocomposite (PUC6@rGO) based on reduced graphene oxide (rGO) and Co-MOF (PUC6) have been developed by the wet impregnation method. The unique structure-morphology relationship between pseudocapacitive PUC6 MOF and highly conducting rGO favours rapid diffusion of ions of the electrolyte, resulting in improved electrochemical behaviour. At the current density of 1 A g-1, the PUC6@rGO nanocomposite electrode demonstrated considerable specific capacitance, i.e. 579 F g-1. This material was used to create a flexible symmetric supercapacitor device that produced very high energy density and power density, i.e. 48.25 Wh kg-1 and 250 W kg-1, respectively. Furthermore, the device capacitance did not degrade even after 10,000 charge-discharge cycles, showcasing superior cyclic stability and providing long-term durability. Additionally, PUC6@rGO was employed as an electrochemical sensor for Cd2+ ion detection, with a low detection limit, i.e. 780 nM, being achieved. The enhanced performance of the supercapacitor and sensor of the designed nanocomposite provides new opportunities for the design of multifunctional materials in the upcoming generation for a technologically sophisticated and ecologically responsible future.