Synthesis and characterization of binder-free Ni, Cu, Mn, and Co metal–organic frameworks for supercapacitors

Abstract

In this study, binder-free Ni, Cu, Mn, and Co metal–organic framework (MOF) electrodes were directly grown on nickel foam (NF) and utilized as effective binder-free electrodes for supercapacitor (SC) applications. The scanning electron microscopy (SEM) studies of the Ni, Co, Cu and Mn MOF revealed unique spherical, flower-like, and sheet-like morphology. The binder-free Co, Cu, Mn, and Ni MOF exhibit surface areas of 141.23 m²/g, 123.57 m²/g, 96.28 m²/g, and 95.92 m²/g, respectively, indicating their potential to serve as highly effective materials for enhanced electrochemical activity. The Ni, Cu, Mn, and Co MOF electrodes achieved a maximum specific capacitance (Cp) of 14, 56,109, and 129 (F/g) at the scan rate of 5 mV/s attained through CV curves and a Cp of 38, 53, 62, and 71 (F/g) attained through GCD curves. The superior electrochemical behavior of binder-free Ni, Cu, Mn, and Co MOF electrodes was ascribed to the increased surface area and electrical conductivity resulting from Ni, Cu, Mn, and Co ions, with the charge storage mechanism primarily governed by diffusion processes. These findings highlight the potential of this method for developing advanced pseudocapacitive materials.