Enhancing supercapacitor performance of Ni–Co–Mn metal–organic frameworks by compositing it with polyaniline and reduced graphene oxide

Abstract

Metal-organic frameworks (MOFs) are one of the most sought-after materials in the domain of supercapacitors and can be tailored to accommodate diverse compositions, making them amenable to facile functionalization. However, their intrinsic specific capacitance as well as energy density is minimal, which hinders their usage for advanced energy storage applications. Therefore, herein, we have prepared six electrodes, <i>i.e.</i>, Ni-Co-Mn MOFs, polyaniline (PANI), and reduced graphene oxide (rGO) along with their novel nanocomposites, <i>i.e.</i>, C₁, C₂, and C₃, comprising MOFs : PANI : rGO in a mass ratio of 100 : 1 : 0.5, 100 : 1 : 1, and 100 : 1 : 10, respectively. The polyaniline conducting polymer and rGO enabled efficient electron transport, enhanced charge storage processes, substantial surface area facilitating higher loading of active materials, promoting electrochemical reactions, and ultimately enhanced nanocomposite system performance. As a result, scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques confirmed the successful synthesis and revealed distinct morphological features of the materials. Following electrochemical testing, it was observed that composition C₂ exhibited the highest performance, demonstrating a groundbreaking specific capacitance of 1007 F g^-1 at 1 A g^-1. The device showed a good energy density of 25.11 W h kg^-1 and a power density of 860 W kg^-1. Remarkably, the device demonstrated a capacity retention of 115% after 1500 cycles, which is a clear indication of the wettability factor, according to the literature. The power law indicated <i>b</i>-values in a range of 0.58-0.64, verifying the hybrid-type behavior of supercapacitors.