Electrochemical studies on Ni, Co & Ni/Co-MOFs for high-performance hybrid supercapacitors

Abstract

Metal-organic framework (MOF) of Ni-MOF, Co-MOF, and Ni/Co-MOF were synthesized by a facile hydrothermal method using Trimesic acid as structure directing linker. The physico-chemical properties of the synthesized MOFs were characterized by P-XRD (powder X-ray diffraction), FT-IR (fourier transform infrared spectroscopy), SEM-EDS (scanning electron microscopy/energydispersive X-ray spectroscopy), HR-TEM (high-resolution transmission tlectron microscope) and BET (Brunner Emmett Teller) surface area techniques. The supercapacitance performance of these MOFs were studied by electroanalytical techniques such as cyclic voltammetry (CV), chronopotentiometry (CP) and electrochemical impedance spectroscopy (EIS). Amongst the MOFs investigated, Ni/Co-MOF exhibited highest specific capacitance (C s ) of 2041 F g −1 at a scan rate of 2 mV s −1 and 980 F g −1 at a current density of 2.5 A g −1 . Ni/Co-MOFs delivered a maximum energy density (ED) of 55.7 W h Kg −1 at a corresponding power density (PD) of 1 K W kg −1 and maximum PD of 9.8 K W kg −1 at an ED of 41.6 W h Kg −1 . An outstanding supercapacitance performance with superior columbic efficiency of 98.4% and capacitive retention of 73% after 5000 cycles marks this material as potential candidate for supercapacitors (SCs). A comparative electrochemical study of these MOFs were made in three electrode system, further electrochemical performance was corelated with their physico-chemical properties.

One step synthesis of a bimetallic (Ni and Co) metal–organic framework for the efficient electrocatalytic oxidation of water and hydrazine

“…All the synthesized MOFs show diffraction peaks at 2y = 10.881, 18.111, 20.621, 22.471, 25.571, and 34.041 due to the planes of (11À1), ( 150), ( 151), ( 220), (02À4), and (025), respectively, which match with the literature value. 23 Zhang and coworkers 24 synthesized mono and bimetallic MOFs and mentioned that all the MOFs exhibit identical diffraction peaks, which depicts that upon the incorporation of a second metal into the framework, the crystal structures remain unaltered. In the present work, we observed no changes in the diffraction peak positions between the mono and bimetallic MOFs similar to the observation of Zhang and coworkers.…”

Three-dimensional Ni4O4-cubane metal–organic framework as a high-performance electrocatalyst for urea oxidation

“…Peaks at 1260 and 1386 cm −1 were ascribed to the –COO– group of pdda coordinated to Ni( ii ). 47 Peaks below 1000 cm −1 were assigned to Ni–O bending and stretching vibrations. 48 The thermal stability of MOF 1 was assessed through TGA: it showed thermal stability up to 380 °C (Fig.…”

An overview of supercapacitors electrode materials based on metal organic frameworks and future perspectives

“…Moreover, the Ni/Co-MOFs supply a maximum energy density of 55.7 Wh/kg at a power density of 1 kW/kg along with columbic efficiency of 98.4% and maximum cyclic stability (73% retention) after 5000 cycles. 166 To analyze the influence of nickel incorporation on the electrochemical response of Co-ZIF, Hong et al in 2019 reported a mixed MOF by replacing the cobalt with nickel in a constant ratio. Through this facile process, the conductivity of MOF was enhanced without the calcination process.…”