| 1. |
- Wang, Yong-Lei, et al.
(författare)
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Microstructural and Dynamical Heterogeneities in Ionic Liquids
- 2020
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Ingår i: Chemical Reviews. - : American Chemical Society (ACS). - 0009-2665 .- 1520-6890. ; 120:13, s. 5798-5877
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Forskningsöversikt (refereegranskat)abstract
- Ionic liquids (ILs) are a special category of molten salts solely composed of ions with varied molecular symmetry and charge delocalization. The versatility in combining varied cation–anion moieties and in functionalizing ions with different atoms and molecular groups contributes to their peculiar interactions ranging from weak isotropic associations to strong, specific, and anisotropic forces. A delicate interplay among intra- and intermolecular interactions facilitates the formation of heterogeneous microstructures and liquid morphologies, which further contributes to their striking dynamical properties. Microstructural and dynamical heterogeneities of ILs lead to their multifaceted properties described by an inherent designer feature, which makes ILs important candidates for novel solvents, electrolytes, and functional materials in academia and industrial applications. Due to a massive number of combinations of ion pairs with ion species having distinct molecular structures and IL mixtures containing varied molecular solvents, a comprehensive understanding of their hierarchical structural and dynamical quantities is of great significance for a rational selection of ILs with appropriate properties and thereafter advancing their macroscopic functionalities in applications. In this review, we comprehensively trace recent advances in understanding delicate interplay of strong and weak interactions that underpin their complex phase behaviors with a particular emphasis on understanding heterogeneous microstructures and dynamics of ILs in bulk liquids, in mixtures with cosolvents, and in interfacial regions.
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| 2. |
- Ahmed, Mukhtiar
(författare)
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Fluorine-Free Ionic Liquid Based Electrolytes: Synthesis and Structural Characterization
- 2022
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Since their introduction by Sony in 1990, lithium-ion batteries (LIBs) have acquired a sizable market share. They have the best energy densities, a high open circuit voltage, a low self-discharge rate, no memory effect, and a slow loss of charge when not in use. These properties make them the most popular rechargeable batteries for portable gadgets, electric vehicles and aerospace applications. They do, however, pose major safety issues since the electrolytes are made up of fluorinated salts dissolved in volatile organic solvents, the former being meta-stable at ambient temperature and the latter being flammable a with high vapour pressure. Thus, there is an urge to develop thermally and electrochemically stable non-fluorinated electrolytes to improve the safety and performance of batteries. Electrolytes based on ionic liquids (ILs) in general offer a range of suitable advantages including low volatility and high thermal and electrochemical stabilities,and can additionally be made fluorine-free. In general, their physicochemical properties are determined by the interactions between the cations and anions, which are controlled by the chemical functionalities present, with vast freedom in structural design to reduce these interactions and enhance also the ion mobilities. In this study, favoring from of “structural design” three different families of fluorine-free ionic liquids-based electrolytes are designed and created. These families of ILs comprising n- tetrabutylphosphonium, imidazolium, pyridinium based cations and pyridine, pyrazine and ether functionalized salicylate-based anions. The structures and purity of these new ILs are characterized by using multinuclear NMR, FTIR and mass spectrometry. Several features and properties of the novel electrolytes are investigated; thermogravimetric analysis, differential scanning calorimetry, ionic conductivity and electrochemical stability. These studies are further complemented by using PFG NMR diffusometry to understand the possible interaction mechanisms between the oppositely charged ions within the electrolytes, and especially, the influence of Li+ addition in the IL-based electrolytes.
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| 3. |
- Ai, Chenxiang, et al.
(författare)
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A knitting copolymerization Strategy to Build Porous Polytriazolium Salts for Removal of Anionic Dyes and MnO4−
- 2022
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Ingår i: Macromolecular rapid communications. - : Wiley. - 1022-1336 .- 1521-3927. ; 43:15
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Tidskriftsartikel (refereegranskat)abstract
- Although considerable efforts have been devoted to novel ionic porous networks (IPNs), the development of them in a scalable manner to tackle the issues in pollutant treatment by adsorption remains an imminent challenge. Herein, inspired by natural spider webs, a knitting copolymerization strategy is proposed to construct analogue triazolium salt-based porous networks (IPN-CSUs). It is not only convenient to incorporate the cationic motifs into the network, but easy to control over the contents of ionic pairs. The as-prepared IPN-CSUs displays a high surface area of 924 m2 g−1, a large pore volume of 1.27 cm3 g−1 and abundant ionic sites, thereby exhibiting fast adsorption rate and high adsorption capacity towards organic and inorganic pollutants. The kinetics and thermodynamics study reveal that the adsorption followed a pseudo-second-order kinetic model and Langmuir isotherm model correspondingly. Specifically, the maximum adsorption capacity of the IPN-CSUs is as high as 1.82 mg mg−1 for permanganate ions and up to 0.54 mg mg−1 for methyl orange, which stands out among the previously reported porous adsorbents so far. It is expected that the strategy reported herein can be extended to the development of other potential efficient adsorbents in water purifications.
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| 4. |
- Ai, Chenxiang, et al.
(författare)
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One-pot construction of nitrogen-rich polymeric ionic porous networks for effective CO2 capture and fixation
- 2022
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Ingår i: Polymer Chemistry. - : Royal Society of Chemistry (RSC). - 1759-9954 .- 1759-9962. ; 13:1, s. 121-129
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Tidskriftsartikel (refereegranskat)abstract
- Facile preparation of ionic porous networks (IPNs) with large and permanent porosity is highly desirable for CO2 capture and transformation but remains a challenge. Here we report a one-pot base-mediated construction of nitrogen-rich IPNs through a combination of nucleophilic substitution and quaternisation chemistry from H-imidazole. This strategy, as proven by the model reactions of 1H-imidazole or 1-methyl-1H-imidazole with cyanuric chloride, allows for fine regulation of porosity and physicochemical properties, leading to nitrogen-rich IPNs featuring abundant ionic units and radicals. The as-prepared networks, termed IPN-CSUs, efficiently capture CO2 (80.1 cc g−1 at 273 K/1 bar) with an ideal CO2/N2 selectivity of 139.7. They can also effectively catalyse the cycloaddition reaction between CO2 and epoxides with high yields of up to 99% under mild conditions (0.1 MPa, 298 K), suggesting their possible applications in the fields of both selective molecular separation and conversion. Unlike the previously known strategies generally involving single coupling chemistry, our strategy combining two coupling routes in one pot appears to be unique and potentially applicable to other building blocks.
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| 5. |
- Ajjan, Fátima, et al.
(författare)
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Innovative polyelectrolytes/poly(ionic liquid)s for energy and the environment
- 2017
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Ingår i: Polymer international. - : WILEY. - 0959-8103 .- 1097-0126. ; 66:8, s. 1119-1128
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Forskningsöversikt (refereegranskat)abstract
- This paper presents the work carried out within the European project RENAISSANCE-ITN, which was dedicated to the development of innovative polyelectrolytes for energy and environmental applications. Within the project different types of innovative polyelectrolytes were synthesized such as poly(ionic liquid)s coming from renewable or natural ions, thiazolium cations, catechol functionalities or from a new generation of cheap deep eutectic monomers. Further, macromolecular architectures such as new poly(ionic liquid) block copolymers and new (semi)conducting polymer/polyelectrolyte complexes were also developed. As the final goal, the application of these innovative polymers in energy and the environment was investigated. Important advances in energy storage technologies included the development of new carbonaceous materials, new lignin/conducting polymer biopolymer electrodes, new iongels and single-ion conducting polymer electrolytes for supercapacitors and batteries and new poly(ionic liquid) binders for batteries. On the other hand, the use of innovative polyelectrolytes in sustainable environmental technologies led to the development of new liquid and dry water, new materials for water cleaning technologies such as flocculants, oil absorbers, new recyclable organocatalyst platforms and new multifunctional polymer coatings with antifouling and antimicrobial properties. All in all this paper demonstrates the potential of poly(ionic liquid)s for high-value applications in energy and enviromental areas. (c) 2017 Society of Chemical Industry
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| 6. |
- Alkarmo, Walid, et al.
(författare)
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Poly(ionic liquid)-Derived N-Doped Carbons with Hierarchical Porosity for Lithium- and Sodium-Ion Batteries
- 2019
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Ingår i: Macromolecular rapid communications. - : Wiley. - 1022-1336 .- 1521-3927. ; 40:1
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Tidskriftsartikel (refereegranskat)abstract
- The performance of lithium- and sodium-ion batteries relies notably on the accessibility to carbon electrodes of controllable porous structure and chemical composition. This work reports a facile synthesis of well-defined N-doped porous carbons (NPCs) using a poly(ionic liquid) (PIL) as precursor, and graphene oxide (GO)-stabilized poly(methyl methacrylate) (PMMA) nanoparticles as sacrificial template. The GO-stabilized PMMA nanoparticles are first prepared and then decorated by a thin PIL coating before carbonization. The resulting NPCs reach a satisfactory specific surface area of up to 561 m(2) g(-1) and a hierarchically meso- and macroporous structure while keeping a nitrogen content of 2.6wt%. Such NPCs deliver a high reversible charge/discharge capacity of 1013 mA h g(-1) over 200 cycles at 0.4A g(-1) for lithium-ion batteries, and show a good capacity of 204 mAh g(-1) over 100 cycles at 0.1A g(-1) for sodium-ion batteries.
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| 7. |
- Álvarez-Gómez, Ainhoa, et al.
(författare)
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Polyacrylonitrile-b-Polystyrene Block Copolymer-Derived Hierarchical Porous Carbon Materials for Supercapacitor
- 2022
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Ingår i: Polymers. - : MDPI AG. - 2073-4360. ; 14:23
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Tidskriftsartikel (refereegranskat)abstract
- The use of block copolymers as a sacrificial template has been demonstrated to be a powerful method for obtaining porous carbons as electrode materials in energy storage devices. In this work, a block copolymer of polystyrene and polyacrylonitrile (PS−b−PAN) has been used as a precursor to produce fibers by electrospinning and powdered carbons, showing high carbon yield (~50%) due to a low sacrificial block content (fPS ≈ 0.16). Both materials have been compared structurally (in addition to comparing their electrochemical behavior). The porous carbon fibers showed superior pore formation capability and exhibited a hierarchical porous structure, with small and large mesopores and a relatively high surface area (~492 m2/g) with a considerable quantity of O/N surface content, which translates into outstanding electrochemical performance with excellent cycle stability (close to 100% capacitance retention after 10,000 cycles) and high capacitance value (254 F/g measured at 1 A/g).
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| 8. |
- Anton, Arthur Markus, et al.
(författare)
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Hydrogen bonding and charge transport in a protic polymerized ionic liquid
- 2020
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Ingår i: Soft Matter. - : Royal Society of Chemistry (RSC). - 1744-683X .- 1744-6848. ; 16:26, s. 6091-6101
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Tidskriftsartikel (refereegranskat)abstract
- Hydrogen bonding and charge transport in the protic polymerized ionic liquid poly[tris(2-(2-methoxyethoxy)ethyl)ammoniumacryloxypropyl sulfonate] (PAAPS) are studied by combining Fourier transform infrared (FTIR) and broadband dielectric spectroscopy (BDS) in a wide temperature range from 170 to 300 K. While the former enables to determine precisely the formation of hydrogen bonds and other moiety-specific quantized vibrational states, the latter allows for recording the complex conductivity in a spectral range from 10(-2)to 10(+9) Hz. A pronounced thermal hysteresis is observed for the H-bond network formation in distinct contrast to the reversibility of the effective conductivity measured by BDS. On the basis of this finding and the fact that the conductivity changes with temperature by orders of magnitude, whereas the integrated absorbance of the N-H stretching vibration (being proportional to the number density of protons in the hydrogen bond network) changes only by a factor of 4, it is concluded that charge transport takes place predominantly due to hopping conduction assisted by glassy dynamics (dynamic glass transition assisted hopping) and is not significantly affected by the establishment of H-bonds.
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| 9. |
- Cao, Wei, et al.
(författare)
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Dual-Cationic Poly(ionic liquid)s Carrying 1,2,4-Triazolium and Imidazolium Moieties : Synthesis and Formation of a Single-Component Porous Membrane
- 2021
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Ingår i: ACS Macro Letters. - : American Chemical Society (ACS). - 2161-1653. ; 10:1, s. 161-166
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Tidskriftsartikel (refereegranskat)abstract
- Both imidazolium and 1,2,4-triazolium cations are important functional moieties widely incorporated as building blocks in poly(ionic liquid)s (PILs). In a classical model, a PIL usually contains either imidazolium or 1,2,4-triazolium in its repeating unit. Herein, via exploiting the slight reactivity difference of alkyl bromide with imidazole and 1,2,4-triazole at room temperature, we synthesized dual-cationic PIL homopolymers carrying both imidazolium and 1,2,4-triazolium moieties in the same repeating unit, that is, an asymmetrically dicationic unit. We investigated their fundamental properties, for example, thermal stability and solubility, as well as their unique function in forming supramolecular porous membranes via a water-initiated phase-separation and cross-linking process. With such knowledge, we identified a water-based fabricate strategy toward air-stable porous membranes from single-component Pits. This study will enrich the design tools and chemical structure library of PILs and expand their application spectrum.
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| 10. |
- Cao, Wei, et al.
(författare)
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Ionic organic cage-encapsulated metal clusters for switchable catalysis
- 2021
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Ingår i: Cell Reports Physical Science. - : Elsevier BV. - 2666-3864. ; 2:9
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Tidskriftsartikel (refereegranskat)abstract
- The capability to build up stable, switchable catalysts for complex artificial systems that can mimic the responsiveness of biological systems to multiple triggers is highly desirable and challenging. Herein, we engineer such a system by physically locking catalytically active metal clusters (MCs) inside individual cationic molecular organic cages (I-Cages), where the responsive and task-specific counteranions of I-Cages impart MCs with a programmable gating effect. This allows for precise spatial and temporal control over chemical reactions by regulating accessibility of reagents to the MC sites. Following this strategy, we have successfully tailored catalytic activity of a series of model catalysis (e.g., methanolysis of ammonia borane, and the reduction of 4-nitroaniline) by employing light and pH stimuli, as well as their combination, for programmable-activity control.
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