| 1. |
- Ahmed, Mukhtiar, et al.
(författare)
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Ionic Liquids and Electrolytes with Flexible Aromatic Anions
- 2023
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Ingår i: Chemistry - A European Journal. - : John Wiley & Sons. - 0947-6539 .- 1521-3765. ; 29:41
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Tidskriftsartikel (refereegranskat)abstract
- Five new n-tetrabutylphosphonium (P4444)+ cation based ionic liquids (ILs) with oligoether substituted aromatic carboxylate anions have been synthesized. The nature and position of the oligoether chain affect thermal stability (up to 330 ºC), phase behaviour (Tg < -55 ºC) and ion transport. Furthermore, with the aim of application in lithium batteries, electrolytes were created for two of the ILs by 10 mol% doping using the corresponding Li-salts. This affects the ion diffusion negatively, from being higher and equal for cations and anions to lower for all ions and unequal. This is due to the stronger ionic interactions and formation of aggregates, primarily between the Li+ ions and the carboxylate group of the anions. Electrochemically, the electrolytes have electrochemical stability windows up to 3.5 V, giving some promise for battery application.
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| 2. |
- Bhowmick, Sourav, et al.
(författare)
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Ambient temperature liquid salt electrolytes
- 2023
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Ingår i: Chemical Communications. - : Royal Society of Chemistry (RSC). - 1364-548X .- 1359-7345. ; 59:18, s. 2620-2623
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Tidskriftsartikel (refereegranskat)abstract
- Alkali metal salts usually have high melting points due to strong electrostatic interactions and solvents are needed to create ambient temperature liquid electrolytes. Here, we report on six phosphate-anion-based alkali metal salts, Li/Na/K, all of which are liquids at room temperature, with glass transition temperatures ranging from −61 to −29 °C, and are thermally stable up to at least 225 °C. While the focus herein is on various physico-chemical properties, these salts also exhibit high anodic stabilities, up to 6 V vs. M/M+ (M = Li/Na/K), and deliver some battery performance - at elevated temperatures as there are severe viscosity limitations at room-temperature. While the battery performance arguably is sub-par, solvent-free electrolytes based on alkali metal salts such as these should pave the way for conceptually different Li/Na/K-batteries, either by refined anion design or by using several salts to create eutectic mixtures.
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| 3. |
- Bhowmick, Sourav, et al.
(författare)
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Physical and electrochemical properties of new structurally flexible imidazolium phosphate ionic liquids
- 2022
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Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 24:38, s. 23289-23300
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Tidskriftsartikel (refereegranskat)abstract
- New structurally flexible 1-methyl- and 1,2-dimethyl-imidazolium phosphate ionic liquids (ILs) bearing oligoethers have been synthesized and thoroughly characterized. These novel ILs revealed high thermal stabilities, low glass transitions, high conductivity and wide electrochemical stability windows up to 6 V. Both anions and cations of 1-methyl-imidazolium ILs diffuse faster than the ions of 1,2-dimethyl-imidazolium ILs, as determined by pulsed field gradient nuclear magnetic resonance (PFG-NMR). The 1-methyl-imidazolium phosphate ILs showed relatively higher ionic conductivities and ion diffusivity as compare with the 1,2-dimethyl-imidazolium phosphate ILs. As expected, the diffusivity of all the anions and cations increases with an increase in the temperature. The 1-methyl-imidazolium phosphate ILs formed hydrogen bonding with the phosphate anions, the strength of which is decreased with increasing temperature, as confirmed by variable temperature 1H and 31P NMR spectroscopy. One of the representative IL, [EmDMIm][DEEP], presented a promising performance at elevated temperatures as an electrolyte in a supercapacitor composed of multiwall carbon nanotubes and activated charcoal (MWCNTs/AC) composite electrodes.
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| 4. |
- Bhowmick, Sourav, et al.
(författare)
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Structurally Flexible Pyrrolidinium- and Morpholinium-based Ionic Liquid Electrolytes
- 2023
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Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry. - 1463-9076 .- 1463-9084. ; 25:29, s. 19815-19823
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Tidskriftsartikel (refereegranskat)abstract
- Ion transport measures and details as well as physico-chemical and electrochemical properties are presented for a small set of structurally flexible pyrrolidinium (Pyrr) and morpholinium (Morph) cation-based ionic liquids (ILs), all with oligoether phosphate-based anions. All have high thermal stabilities, low glass transition temperatures, and wide electrochemical stability windows, but rather moderate ionic conductivities, whereas both the anions and the cations of the Pyrr-based ILs diffuse faster than those of the Morph-based ILs. Overall the former ILs have significantly more promise as high-temperature supercapacitor electrolytes, rendering a specific capacitance of 164 F g−1 at 1 mV s−1, a power density of 241 W kg−1 and a specific energy density of 30 Wh kg−1 at 90 °C in a symmetric graphite supercapacitor.
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| 5. |
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| 6. |
- Kumar, Saurabh, et al.
(författare)
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Topical progress in medicinal applications of self‐assembled organoplatinum complexes using diverse Pt(II)‐ and N‐based tectons
- 2022
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Ingår i: Applied organometallic chemistry. - : John Wiley & Sons. - 0268-2605 .- 1099-0739. ; 36:11
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Forskningsöversikt (refereegranskat)abstract
- The last decade witnessed a flourishing advancement in the design and synthesis of discrete Pt-based metallamacrocycles self-assembled using coordination bonds. Such supramolecular entities were obtained using novel nitrogen-based ligands and have wide and versatile applications such as chemical sensors, catalysts, theranostic agents, optical materials, drug delivery, and others. Herein, we present a concise review of recently reported metallacycles obtained using various N-functionalized donor and Pt acceptor tectons of various shapes and sizes. While highlighting recent developments in the syntheses and characterization of such platinacycles, we lay special emphasis on their biological interactions and applications.
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| 7. |
- Tatrari, Gaurav, et al.
(författare)
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Charge storage performance of a structurally flexible hybrid ionic liquid electrolyte
- 2024
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Ingår i: Energy Storage. - : John Wiley & Sons. - 2578-4862 .- 2578-4862.
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Tidskriftsartikel (refereegranskat)abstract
- The electrochemical and charge storage performance of a fluorine-free structurally flexible hybrid pyrrolidinium-based ionic liquid electrolyte (HILE) in a symmetric graphite-based supercapacitor is thoroughly investigated. The HILE revealed thermal decomposition at above 230°C, a glass transition (Tg) temperature of below −70°C, and ionic conductivity of 0.16 mS cm−1 at 30°C. The chemical and electrochemical properties are investigated using a systematic variable temperature 1H and 31P NMR spectroscopy and diffusometry, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge-discharge (GCD). The supercapacitor demonstrated a notable specific capacitance of 186 F g−1 at a scan rate of 1 mV s−1 and a specific capacitance of 122 F g−1 at a current density of 0.5 A g−1. The maximum energy density of 48.8 Wh kg−1, a power density of 450 W kg−1 at a current density of 0.5 A g−1, and a potential window of 4 V were obtained. Altogether, this study demonstrates that the new HILE can be used in symmetric graphite-based supercapacitors over a wide potential window of 4 V and a temperature range from −20°C to 90°C.
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| 8. |
- Xu, Yanqi, et al.
(författare)
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Fluorine-Free “Solvent-in-Salt” Sodium Battery Electrolytes: Solvation Structure and Dynamics
- 2024
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Ingår i: Energy Advances. - : Royal Society of Chemistry. - 2753-1457. ; 3:3, s. 564-573
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Tidskriftsartikel (refereegranskat)abstract
- The solvation structure, dynamics, and transport properties, as well as thermal and electrochemical stabilities of “solvent-in-salt” (SIS) electrolytes, also known as highly concentrated electrolytes, are far from fully understood. Furthermore, these special types of electrolytes are almost without exception based on fluorinated salts. In contrast, here we report on fluorine-free SIS electrolytes comprising ambient temperature liquid sodium bis(2-(2-ethoxyethoxy)ethyl)phosphate (NaDEEP) salt and tris(2-(2-ethoxyethoxy)ethyl)phosphate (TEOP) solvent, for which the ionic conductivities and ion diffusivities are altered profoundly as the salt concentration is increased. A careful molecular level analysis reveals a microstructure with a “solvent-rich” phase with almost an order of magnitude faster ion diffusion than in a “salt-rich” phase. Aggregated ionic structures in these SIS electrolytes lead to higher ionic conductivities alongside lower glass transition temperatures, <−80 °C, but also agreeable thermal stabilities, up to 270 °C, and improved anodic stabilities, possibly up to 7.8 V vs. Na/Na+ and at least >5 V vs. Na/Na+. Altogether, this provides a foundation for both better understanding and further development of fluorine-free SIS electrolytes for sodium batteries.
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