Heterostructure ZIF-derived Nanoporous Carbon-based Electrode Materials for Supercapacitors /

Abstract

Supercapacitors are energy storage devices that can store energy from sources like solar and wind energy. They differ from batteries in that they may be fully charged and fully discharged in a matter of seconds. The active surface area, electrical conductivity, and long-term stability of the material have all been improved in numerous ways. The zeolitic imidazolate framework (ZIF), a class of the metalorganic framework, binds metal ions and organic molecules (MOF). Carbon hosts may be synthesized from zeolitic imidazolate frameworks (ZIFs). In this research work, two different strategies were used, i.e., nanostructure and nanocomposites, to explore the impact of nanoporous carbon-based electrode materials on supercapacitors. Initially, porous carbon and metal oxide/sulfide electrode materials derived from ZIF- 67 were synthesized in two different solvents, water, and methanol, in a simple and cost-effective method. Afterward, the anion exchange phase of sulfidation has a significant impact on the structural characteristics of porous carbon produced from ZIF-67 through pyrolysis. The improved electrochemical performance (for the sulfidebased electrode) was ascribed to its hierarchical structure. Nickel hydroxide (Ni (OH)2) based layered morphology was embedded into nitrogen-doped porous carbon nanotube-based sulfide as a further modification. At 100 mV/s, electrode heterostructures can increase capacitive control by up to 98 percent. For the nanocomposites-based electrode analysis, a single metallic and bimetallic ZIF strategy is used from ZIF-67 derived carbon material. The Co-based metal-organic frameworks (ZIF-67) were sandwiched between MXene nanosheets and subsequently reduced into cobalt-based porous nitrogen-doped CNTs. The composite achieved high electronic conductivity and structural flexibility using MXene nanosheets. Research showed that the modified composite exhibits meager resistance to charge transfer, a quick frequency response time, and an increased specific capacitance value. Cobaltbased metal-organic frameworks (ZIF-67) were also sandwiched between MXene nanosheets and subsequently reduced into cobalt-based porous nitrogen-doped CNTs. They all have similar benefits, such as being electrically conductive, having short diffusion paths, being economically feasible, and being simple to produce into a variety of structures with a wide surface area. ZIF using a heteroatom approach may result in a more significant density of defects, synergistic effects between various metals, and an increase in electroactive redox processes, among other impacts. The electron conductivity and behavior of electrochemical applications were improved because of the three-dimensional microporous-mesoporous structure. Breakthrough was incorporating extra Al-Ti3C2 MXene into a nitrogen-doped CTNs-based porous carbon framework. ZIF-derived porous carbon has 1605 F/g at 5 mV/s and a short Rct.