Thermodynamic study of POSS-based ionic liquids with various numbers of ion pairs

Tanaka, Kazuo; Ishiguro, Fumiyasu; Chujo, Yoshiki

doi:10.1038/pj.2011.54

Cited by 53 publications

(57 citation statements)

References 37 publications

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“…that was assigned to the T 8 POSS structure. 25,26 These data indicate that the POSS cage is not significantly degraded in the final products. The integration of the peaks in the 1 H nuclear magnetic resonance spectra indicates the formation of 1:8 ion pairs of POSS-(COOH) 8 and imidazolium cation.…”

Section: Resultsmentioning

confidence: 54%

“…25,26 Thus, it is likely that the molecular distribution of the ion pairs that are tethered to the POSS core in the crystals remain the same after melting, meaning that a star-shaped structure might be maintained before and after melting. Based on these presumptions, we aimed to align the POSS molecules to form regular structures in the liquid phase.…”

Section: Resultsmentioning

confidence: 99%

“…The decomposition fragment of the molecule can be determined by evaluating the vertical bars in these profiles (from the weight loss to the molecular weight). 25,26 As a result, the decomposition process was Scheme 1 Chemical structures and synthetic scheme for preparing the ion salts used in this study.…”

Section: Resultsmentioning

confidence: 99%

“…[10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] We recently reported the synthesis of POSS-based ILs, and we investigated their thermal properties. 25,26 By tethering multiple ion pairs composed of imidazolium cations and carboxylates to the vertices of POSS cores or by simply adding POSS molecules with acid groups, the melting temperatures of the ion pairs decreased and their thermal stabilities increased. [25][26][27][28] In the crystalline state, the POSS core can isolate each ion pair.…”

Section: Introductionmentioning

confidence: 99%

“…25,26 By tethering multiple ion pairs composed of imidazolium cations and carboxylates to the vertices of POSS cores or by simply adding POSS molecules with acid groups, the melting temperatures of the ion pairs decreased and their thermal stabilities increased. [25][26][27][28] In the crystalline state, the POSS core can isolate each ion pair. As a result, the intermolecular interactions are reduced, and thus the melting temperatures are decreased.…”

Section: Introductionmentioning

confidence: 99%

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POSS ionic liquid crystals

et al. 2015

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Here we report the use of unique organic − inorganic hybrid materials composed of octa-substituted polyhedral oligomeric silsesquioxane (POSS) cores as ionic liquid (IL) crystals. These materials have a wide temperature range in which they exist in liquid crystal (LC) phase because of the stabilizing effect of the POSS core. We synthesized ion pairs composed of alkyl chainsubstituted imidazolium and carboxylates of various lengths that were or were not connected to the POSS core; then the thermal properties of these materials were investigated. It was found that both ion salts and the octadecyl-substituted imidazolium ion pairs with or without connection to POSS could form LCs. Interestingly, the LC phase of the POSS-tethered ion salts was maintained until decomposition. In contrast, the octadecyl-substituted imidazolium ion salts that were not tethered to the POSS core showed a clearance point during heating. The highly symmetric structure of POSS contributes not only to the suppression of the molecular motion of the ion salts, but also results in the formation of regular structures, leading to thermally stable, thermotropic IL crystals. In addition, by using electrostatic interactions originating among ionic moieties, robust chiral structures can be produced. 3,4 Even a small quantity of chiral ionic sources can efficiently induce enantiomeric structures in a bulk sample, and ionic moieties can be assembled to form regularly ordered structures. 5,6 These well-ordered ionic moieties are expected to work as efficient cation carriers and scaffolds for ordering cations. These materials, which comprise closely assembled ionic species, can exhibit interesting optical and magnetic properties. Thus, new molecular designs for preparing thermally stable LCs composed of ionic species are needed to produce advanced functional materials.The concept of supported IL phases (SILPs) has been recently proposed. Several materials based on SILPs have exhibited important characteristics such as high ion conductivity and compatibility with organic reaction media; these materials have been used as templates for the formation of nanostructures. 1 Silica supports improve the thermal stability of LCs. 7,8 Carmichael et al. 9 have synthesized and explored silicon wafer-assisted SILP materials. They created layers with thicknesses between 10 and 21 nm of an ionic LC with [C 18 C 1 Im] [PF 6 ] on the planar wafer surface and found that the ionic LC formed a mesophase. Inspired by their work, Wasserscheid et al. 7 fabricated SILP materials using silicon nanoparticles and used them as supports for preparing mesoporous structures that could act as effective gasphase catalysts. 8 To construct advanced materials based on the concept of SILP materials, their properties must be fine-tuned according to preprogramed designs at the molecular level. A wide variety of

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Section: Resultsmentioning

confidence: 54%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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POSS ionic liquid crystals

et al. 2015

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A Separator with a Novel Thermal Crosslinking Structure Based on Electrospun PI/A‐POSS for Lithium‐Ion Battery with High Safety and Outstanding Electrochemical Performance

Song

Wang

Zhao

et al. 2021

Adv Materials Inter

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In this study, a polyimide/aminopropyllsobutyl polyhedral oligomeric silsesquioxane (PI/A‐POSS) membrane with a novel 3D thermal crosslinking structure is prepared by electrospinning and subsequent imidization. Compared with the pure PI membrane, PI/A‐POSS composite membranes present better mechanical properties, narrower distribution of pore size, smaller average pore size, and better thermal stability. When A‐POSS content is 3 wt%, the composite membrane (A3) has outstanding electrolyte uptake, excellent ionic conductivity, low interfacial resistance, and the high electrochemical stability of anode. The battery assembled with the A3 separator has an excellent first discharge capacity of 137.8 mAh g−1 and its capacity retention rate is still as high as 76.49% after 100 cycles at 2.0 C. Furthermore, battery assembled with the A3 separator shows excellent rate capacity with a relatively high discharge capacity up to 169.7 mAh g−1 at 0.2 C and a superior capacity recovery rate of 98.06% at 30 °C. Especially, the battery assembled with the A3 separator shows more prominent rate capacity with an excellent first discharge capacity up to 180.5 mAh g−1 at 0.2 C and a superior capacity recovery rate of 95.79% at 60 °C.

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Organosilicon‐Based Functional Electrolytes for High‐Performance Lithium Batteries

Wang

Chen

et al. 2021

Advanced Energy Materials

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Nowadays excessive consumption of fossil fuels due to population growth and industrial development induced serious energy and environmental crisis. To alleviate the ecological crisis and comply with the ever-increasing energy demand, developingThe electrolyte has been considered as a key factor toward higher energy density for Li-ion and Li-metal batteries. However, conventional electrolytes suffer from uncontrolled interfacial reactions and irreversible decomposition causing performance deterioration and potential safety hazard. Organosilicon compounds have attracted great interest as promising electrolyte components due to facile chemical modifications, low glass transition temperatures (T g ), superior chemical, and thermal stabilities. Considerable investigation efforts have been devoted to developing better overall performance of organosilicon-based electrolytes in the past few years. Herein, the recent research progress of organosilicon-based functional electrolytes for the development of liquid, gel, and solid state electrolytes in Li-ion and Li-metal batteries is summarized. Attention is devoted to various types of organosilicon such as silane, siloxane, polysiloxane, and polyhedral oligomeric silsesquioxanes in terms of molecular design, ionic conductivity, functions shown in batteries, thermal, chemical, electrochemical stability, safety, etc. The feasible strategies are also discussed that may promote the comprehensive electrochemical performances of organosilicon-based electrolytes in different types of electrolytes and batteries. Finally, the challenges facing organosilicon-based electrolytes and proposed their possible solutions are presented alongside promising development directions.

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Thermodynamic study of POSS-based ionic liquids with various numbers of ion pairs

Cited by 53 publications

References 37 publications

POSS ionic liquid crystals

POSS ionic liquid crystals

A Separator with a Novel Thermal Crosslinking Structure Based on Electrospun PI/A‐POSS for Lithium‐Ion Battery with High Safety and Outstanding Electrochemical Performance

Organosilicon‐Based Functional Electrolytes for High‐Performance Lithium Batteries

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