Dual redox center-based copper-cobalt metal–organic framework as pseudocapacitive electrode material for supercapacitor

Abstract

Metal-organic frameworks (MOFs) are gaining much attention in the field of energy storage due to their porosity and hybrid properties of inorganic–organic constituents. We report a synthesis of CuCo-MOF (CCM) using benzene-1,4-dicarboxylic acid as an organic linker via a less expensive reflux condensation method, which provides abundant active redox metal centers and accessible carbonyl-based redox sites for energy storage. Furthermore, XRD, FT-IR, Raman, SEM, and XPS are used to examine the crystalline structure and size, functional groups, morphology, and chemical states present in the CCM material respectively. The SEM micrograph shows sponge-like morphology which offers ion encapsulation ability helpful for fast electrolyte ion adsorption and desorption on the electrode surface. From BET analysis the surface area obtained was 192.027 m²/g for CCM material. Additionally, the CCM electrode exhibits excellent pseudocapacitive characteristics with a specific capacitance of 102.4F/g with remarkable energy and power density of 11.37 Wh kg⁻¹ and 285.71 W kg⁻¹ in the potential window range of −0.4 to 0.4 V at 3 mA cm⁻² in a 2 M KOH electrolyte. To check the practical applicability, an asymmetric solid-state device was constructed which delivered an excellent specific capacitance of 111F/g with a maximum energy density of 22.2 Wh kg⁻¹ and a power density of 1800 W kg⁻¹. Therefore, the prepared CCM material plays a crucial role in the energy storage phenomenon.