Cyclodextrin/Graphene-Based Porous Carbon Nanofibers with Embedded MnO₂ Nanoparticles for Supercapacitor Applications

Abstract

Three kinds of free-standing cyclodextrin (CD)/graphene-based porous carbon nanofiber (CNF) composites with MnO2 prepared using α-, β-, and γ-CD are investigated for their morphological and electrochemical properties to compare their electrochemical applicability in aqueous electrolytes. The stability of the optimized structure of γ-CD/graphene-based porous CNF with MnO2 (PMnG­(γ)) is confirmed by density functional theory calculations. Results show that when graphene is added, MnCl2 forms an inclusion complex with γ-CD well, and then MnO2 particles are embedded in the CNF matrix under the influence of these inclusion complexes after heat treatment. The PMnG­(γ) composites, in which the electrochemically active material of MnO2 particles is embedded in the fiber, maximize the synergistic effect of the pseudocapacity of MnO2 and the electric double-layer capacity induced by the highly porous surface. Hence, the PMnG­(γ) electrodes exhibit high specific capacitance (235 Fg–1 at a constant current density of 1 mA cm–2), energy density (25.5–12.2 Wh kg–1 at power densities ranging from 400 to 10,000 W kg–1), and high long-term stability of more than 96% after 10,000 cycles in aqueous solution.

Recent Breakthroughs in Supercapacitors Boosted by Macrocycles

“…Through the influence of CD on MnCl 2 , γ‐CD/graphene‐based porous carbon nanofiber (CNF) composites with MnO 2 , PMnG(γ) was prepared and used as electrode material for SCs (Figure 10a). [154] In the HRTEM image (Figure 10b) and EDX mapping (Figure 10c) of PMnG(γ), the PMnG(γ) nanoparticles were well protected in the fiber because of CD on MnCl 2 . Also, MnO 2 particles were uniformly embedded in the CNF matrix, maximizing the effect of MnO 2 pseudocapacity.…”

“…Panels (b-g) were reproduced from ref. [154] Copyright (2022), with permission from the American Chemical Society. electrolyte ions reaching NiMoO 4 surfaces via the established channels.…”

“…Inset represents CV curves at a scan rate of 75 mV s À 1 before and after running for 10,000 cycles. Panels (b-g) were reproduced from ref [154]. Copyright (2022), with permission from the American Chemical Society.…”

Ultrafast Synthesis of Graphene‐Embedded Cyclodextrin‐Metal‐Organic Framework for Supramolecular Selective Absorbency and Supercapacitor Performance

“…used a microwave method to synthesize γ‐CD‐MOFs in 1 h. [ 11 ] These problems must be addressed during the actual design and application of CD‐MOFs. Combined with the special cavity structure of CDs, CD‐MOFs endow the flexibility in synthesis and design of MOFs, and have been found widespread applications in various fields, [ 14 ] including template‐based synthesis of nanoparticle, [ 15 ] electrochemistry, [ 16 ] drug delivery, [ 17 ] catalyst supports, [ 18 ] adsorption, and separation. [ 19 ]…”

Carbon Nanomaterials Made from Supramolecular Hybridization of Cucurbit[6]uril with Phosphomolybdic Acid for Supercapacitors

“…Macrocyclic compounds [such as crown ethers, cyclodextrins (CDs), calixarenes (CAs), cucurbit­[ n ]­urils (Q­[ n ]­s), and pillararenes (PAs)] have an affinity for organic molecules or metal complexes to form supramolecular species. − The CDs- and CAs-doped electrode materials of SCs developed uniform mesoporosity during the self-pyrolysis to construct porous structures and realize heteroatom hybridization . Like supramolecular hosts, cage-like cucurbit­[n]­urils (Q­[ n ], n = 5–8, 10, 13–15) are constructed with two electronegative carbonyl ports and a hydrophobic inner cavity.…”