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1.
Adv Sci (Weinh) ; 10(6): e2204672, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36575151

RESUMO

Honeycomb-layered oxides with monovalent or divalent, monolayered cationic lattices generally exhibit myriad crystalline features encompassing rich electrochemistry, geometries, and disorders, which particularly places them as attractive material candidates for next-generation energy storage applications. Herein, global honeycomb-layered oxide compositions, Ag2 M2 TeO6 ( M = Ni , Mg , etc $M = \rm Ni, Mg, etc$ .) exhibiting Ag $\rm Ag$ atom bilayers with sub-valent states within Ag-rich crystalline domains of Ag6 M2 TeO6 and Ag $\rm Ag$ -deficient domains of Ag 2 - x Ni 2 TeO 6 ${\rm Ag}_{2 - x}\rm Ni_2TeO_6$ ( 0 < x < 2 $0 < x < 2$ ). The Ag $\rm Ag$ -rich material characterized by aberration-corrected transmission electron microscopy reveals local atomic structural disorders characterized by aperiodic stacking and incoherency in the bilayer arrangement of Ag $\rm Ag$ atoms. Meanwhile, the global material not only displays high ionic conductivity but also manifests oxygen-hole electrochemistry during silver-ion extraction. Within the Ag $\rm Ag$ -rich domains, the bilayered structure, argentophilic interactions therein and the expected Ag $\rm Ag$ sub-valent states ( 1 / 2 + , 2 / 3 + $1/2+, 2/3+$ , etc.) are theoretically understood via spontaneous symmetry breaking of SU(2)× U(1) gauge symmetry interactions amongst 3 degenerate mass-less chiral fermion states, justified by electron occupancy of silver 4 d z 2 $4d_{z^2}$ and 5s orbitals on a bifurcated honeycomb lattice. This implies that bilayered frameworks have research applications that go beyond the confines of energy storage.

2.
ACS Appl Mater Interfaces ; 14(12): 14302-14312, 2022 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-35302758

RESUMO

Potassium-ion batteries (PIBs) have been lauded as the next-generation energy storage systems on account of their high voltage capabilities and low costs and the high abundance of potassium resources. However, the practical utility of PIBs has been heavily encumbered by severe K metal dendrite formation, safety issues, and insufficient electrochemical performance during operations─indeed critical issues that underpin the need for functional electrolytes with high thermal stability, robust solid-electrolyte interphase (SEI)-forming capabilities, and high electrochemical performance. In a bid to establish a knowledge framework for harnessing high rate capabilities and long cycle life from graphite negative electrodes, this study presents the physical properties and electrochemical behavior of a high K+ concentration inorganic ionic liquid (IL) electrolyte, K[FSA]-Cs[FSA] (FSA- = bis(fluorosulfonyl)amide) (54:46 in mol), at an intermediate temperature of 70 °C. This IL electrolyte demonstrates an ionic conductivity of 2.54 mS cm-1 and a wide electrochemical window of 5.82 V. Charge-discharge tests performed on a graphite negative electrode manifest a high discharge capacity of 278 mAh g-1 (0.5 C) at 70 °C, a high rate capability (106 mAh g-1 at 100 C), and a long cyclability (98.7% after 450 cycles). Stable interfacial properties observed by electrochemical impedance spectroscopy during cycling are attributed to the formation of sulfide-rich all-inorganic SEI, which was examined through X-ray photoelectron spectroscopy. The performance of the IL is collated with that of an N-methyl-N-propylpyrrolidinium-based organic IL to provide insight into the synergism between the highly concentrated K+ electrolyte at intermediate temperatures and the all-inorganic SEI during electrochemical operations of the graphite negative electrode.

4.
Sci Rep ; 11(1): 21307, 2021 10 29.
Artigo em Inglês | MEDLINE | ID: mdl-34716346

RESUMO

Cartilage tissues have poor self-repairing abilities. Regenerative medicine can be applied to recover cartilage tissue damage in the oral and maxillofacial regions. However, hitherto it has not been possible to predict the maturity of the tissue construction after transplantation or to prepare mature cartilage tissues before transplantation that can meet clinical needs. Macrophages play an important role in cartilage tissue regeneration, although the exact mechanisms remain unknown. In this study, we established and verified an in vitro experimental system for the direct co-culture of cell pellets prepared from mouse auricular chondrocytes and macrophages polarized into four phenotypes (M1-like, M1, M2-like, and M2). We demonstrate that cartilage pellets co-cultured with M1-like promoted collagen type 2 and aggrecan production and induced the most significant increase in chondrogenesis. Furthermore, M1-like shifted to M2 on day 7 of co-culture, suggesting that the cartilage pellet supplied factors that changed the polarization of M1-like. Our findings suggest that cartilage regenerative medicine will be most effective if the maturation of cartilage tissues is induced in vitro by co-culture with M1-like before transplantation.


Assuntos
Cartilagem/crescimento & desenvolvimento , Condrócitos/fisiologia , Condrogênese/fisiologia , Macrófagos/fisiologia , Agrecanas/metabolismo , Animais , Células Cultivadas , Técnicas de Cocultura/métodos , Colágeno/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Fenótipo , Regeneração , Engenharia Tecidual
5.
Int J Mol Sci ; 22(17)2021 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-34502382

RESUMO

Tumor-associated macrophages (TAMs) promote cancer cell proliferation and metastasis, as well as anti-tumor immune suppression. Recent studies have shown that tumors enhance the recruitment and differentiation of TAMs, but the detailed mechanisms have not been clarified. We thus examined the influence of cancer cells on the differentiation of monocytes to TAM subsets, including CD163+, CD204+, and CD206+ cells, in oral squamous cell carcinoma (OSCC) using immunohistochemistry, flow cytometry, and a cytokine array. Furthermore, we investigated the effect of OSCC cells (HSC-2, SQUU-A, and SQUU-B cells) on the differentiation of purified CD14+ cells to TAM subsets. The localization patterns of CD163+, CD204+, and CD206+ in OSCC sections were quite different. The expression of CD206 on CD14+ cells was significantly increased after the co-culture with OSCC cell lines, while the expressions of CD163 and CD204 on CD14+ cells showed no change. High concentrations of plasminogen activator inhibitor-1 (PAI-1) and interleukin-8 (IL-8) were detected in the conditioned medium of OSCC cell lines. PAI-1 and IL-8 stimulated CD14+ cells to express CD206. Moreover, there were positive correlations among the numbers of CD206+, PAI-1+, and IL-8+ cells in OSCC sections. These results suggest that PAI-1 and IL-8 produced by OSCC contribute to the differentiation of monocytes to CD206+ TAMs.


Assuntos
Macrófagos/metabolismo , Carcinoma de Células Escamosas de Cabeça e Pescoço/metabolismo , Carcinoma de Células Escamosas/patologia , Diferenciação Celular/genética , Linhagem Celular Tumoral , Neoplasias de Cabeça e Pescoço/patologia , Humanos , Imuno-Histoquímica , Interleucina-8/metabolismo , Interleucina-8/fisiologia , Leucócitos Mononucleares/citologia , Macrófagos/fisiologia , Inibidor 1 de Ativador de Plasminogênio/metabolismo , Inibidor 1 de Ativador de Plasminogênio/fisiologia , Carcinoma de Células Escamosas de Cabeça e Pescoço/patologia , Microambiente Tumoral , Macrófagos Associados a Tumor/metabolismo , Macrófagos Associados a Tumor/fisiologia
6.
Nat Commun ; 12(1): 4660, 2021 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-34341351

RESUMO

Honeycomb layered oxides constitute an emerging class of materials that show interesting physicochemical and electrochemical properties. However, the development of these materials is still limited. Here, we report the combined use of alkali atoms (Na and K) to produce a mixed-alkali honeycomb layered oxide material, namely, NaKNi2TeO6. Via transmission electron microscopy measurements, we reveal the local atomic structural disorders characterised by aperiodic stacking and incoherency in the alternating arrangement of Na and K atoms. We also investigate the possibility of mixed electrochemical transport and storage of Na+ and K+ ions in NaKNi2TeO6. In particular, we report an average discharge cell voltage of about 4 V and a specific capacity of around 80 mAh g-1 at low specific currents (i.e., < 10 mA g-1) when a NaKNi2TeO6-based positive electrode is combined with a room-temperature NaK liquid alloy negative electrode using an ionic liquid-based electrolyte solution. These results represent a step towards the use of tailored cathode active materials for "dendrite-free" electrochemical energy storage systems exploiting room-temperature liquid alkali metal alloy materials.

7.
Chem Commun (Camb) ; 56(65): 9272-9275, 2020 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-32657292

RESUMO

Honeycomb layered oxides from Na2Ni2-xCoxTeO6 family were assessed for use as positive electrodes in rechargeable sodium batteries at ambient and elevated temperatures using ionic liquids. Substitution of nickel with cobalt increases the discharge voltage to nearly 4 V (versus Na+/Na), surpassing the average voltages of most Na based layered oxide positive electrodes.

8.
ACS Appl Mater Interfaces ; 12(32): 36168-36176, 2020 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-32692540

RESUMO

The limited cyclability and inferior Coulombic efficiency of graphite negative electrodes have been major impediments to their practical utilization in potassium-ion batteries (PIBs). Herein, for the first time, potassium difluorophosphate (KDFP) electrolyte additive is demonstrated as a viable solution to these bottlenecks by facilitating the formation of a stable and K+-conducting solid-electrolyte interphase (SEI) on graphite. The addition of 0.2 wt % KDFP to the electrolyte results in significant improvements in the (de)potassiation kinetics, capacity retention (76.8% after 400 cycles with KDFP vs 27.4% after 100 cycles without KDFP), and average Coulombic efficiency (∼99.9% during 400 cycles) of the graphite electrode. Moreover, the KDFP-containing electrolyte also enables durable cycling of the K/K symmetric cell at higher efficiencies and lower interfacial resistance as opposed to the electrolyte without KDFP. X-ray diffraction and Raman spectroscopy analyses have confirmed the reversible formation of a phase-pure stage-1 potassium-graphite intercalation compound (KC8) with the aid of KDFP. The enhanced electrochemical performance by the KDFP addition is discussed based on the analysis of the SEI layer on graphite and K metal electrodes by X-ray photoelectron spectroscopy.

9.
J Phys Chem B ; 124(29): 6341-6347, 2020 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-32598152

RESUMO

Potassium-ion batteries (PIBs) are a promising post-lithium-ion battery (LIB), as their resources are abundant and low-cost and may have a higher voltage than LIBs. However, the high operating voltage and extremely high reactivity of potassium metal require a chemically safe electrolyte with oxidative and reductive stabilities. In this study, a potassium single cation ionic liquid (K-SCIL), which contains only K+ as the cationic species and has a high electrochemical stability, low flammability, and low vapor pressure, is developed as an electrolyte for PIBs. The mixture of potassium bis(fluorosulfonyl)amide and potassium (fluorosulfonyl)(trifluoromethylsulfonyl)amide at a molar ratio of 55:45 had the lowest melting point of 67 °C. The K+ concentration in this K-SCIL is high (8.5 mol dm-3 at 90 °C) due to the absence of solvents and bulky organic cations. In addition, the electrochemical window is as wide as 5.6 V, which enables the construction of PIBs with a high energy density. A high current density can be achieved with this K-SCIL, owing to the absence of a K+ concentration gradient. The electrolyte was successfully used with a graphite negative electrode, enabling the reversible intercalation/deintercalation of K+, as confirmed by X-ray diffraction.

10.
Sci Rep ; 9(1): 14611, 2019 10 10.
Artigo em Inglês | MEDLINE | ID: mdl-31601953

RESUMO

Tumor-associated macrophages (TAMs) promote tumor progression and inhibit anti-tumor immune response by producing various mediators and preferentially express CD163, CD204, and CD206. However, the role of these TAM subsets in oral squamous cell carcinoma (OSCC) remains unclear. Here we investigated the expression and function of TAM subsets in OSCC, especially in cancer cell proliferation. Biopsy sample from 44 patients with OSCC were examined for the expression of TAM markers and EGF by immunohistochemistry. EGF production of TAM subsets isolated from OSCC patients was assessed by flow cytometry. We also examined the effect of conditioned medium from TAM subsets on the proliferation of OSCC cells. CD163+ cells were detected diffusely all over the tumor and connective tissue area, while CD204+ and CD206+ cells were mainly detected in/around the tumors. Flow cytometric analysis found that CD206+ TAMs strongly produced EGF compared with CD163+ and CD204+ TAMs. Cell proliferation and invasion of OSCC cells cultured with conditioned medium of CD206+ TAMs were strongly enhanced and inhibited by anti-EGFR. The number of CD206+ TAMs positively correlated with worse clinical prognosis. Our results revealed differences in localization and EGF production among these TAM subsets. CD206+ TAMs might play a critical role in the proliferation of OSCC via EGF production.


Assuntos
Carcinoma de Células Escamosas/metabolismo , Fator de Crescimento Epidérmico/metabolismo , Lectinas Tipo C/metabolismo , Macrófagos/citologia , Lectinas de Ligação a Manose/metabolismo , Neoplasias Bucais/metabolismo , Receptores de Superfície Celular/metabolismo , Microambiente Tumoral , Adulto , Idoso , Idoso de 80 Anos ou mais , Antígenos CD/metabolismo , Antígenos de Diferenciação Mielomonocítica/metabolismo , Biópsia , Carcinoma de Células Escamosas/patologia , Proliferação de Células , Progressão da Doença , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Imuno-Histoquímica , Masculino , Receptor de Manose , Pessoa de Meia-Idade , Neoplasias Bucais/patologia , Invasividade Neoplásica , Receptores Depuradores Classe A/metabolismo
11.
Chem Commun (Camb) ; 55(7): 985-988, 2019 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-30608071

RESUMO

The designing of high voltage cathode materials is critical for the advancement of potassium-ion (K-ion) battery. Herein, we present a new honeycomb framework P2-type K2/3Ni1/3Co1/3Te1/3O2 (or equivalently written as K2NiCoTeO6) which exhibits the highest voltage on record (beyond 4 V versus K+/K) for layered cathode materials. This work will allow for the further development of, particularly, high voltage layered cathodes for K-ion battery.

12.
Nat Commun ; 9(1): 3823, 2018 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-30237549

RESUMO

Rechargeable potassium-ion batteries have been gaining traction as not only promising low-cost alternatives to lithium-ion technology, but also as high-voltage energy storage systems. However, their development and sustainability are plagued by the lack of suitable electrode materials capable of allowing the reversible insertion of the large potassium ions. Here, exploration of the database for potassium-based materials has led us to discover potassium ion conducting layered honeycomb frameworks. They show the capability of reversible insertion of potassium ions at high voltages (~4 V for K2Ni2TeO6) in stable ionic liquids based on potassium bis(trifluorosulfonyl) imide, and exhibit remarkable ionic conductivities e.g. ~0.01 mS cm-1 at 298 K and ~40 mS cm-1 at 573 K for K2Mg2TeO6. In addition to enlisting fast potassium ion conductors that can be utilised as solid electrolytes, these layered honeycomb frameworks deliver the highest voltages amongst layered cathodes, becoming prime candidates for the advancement of high-energy density potassium-ion batteries.

13.
Sci Rep ; 7(1): 1755, 2017 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-28496107

RESUMO

Tumor-associated macrophages (TAMs) promote cancer cell proliferation, invasion, and metastasis by producing various mediators. Although preclinical studies demonstrated that TAMs preferentially express CD163 and CD204, the TAM subsets in oral squamous cell carcinoma (OSCC) remain unknown. In this study, we examined the expression and role of TAM subsets in OSCC. Forty-six patients with OSCC were analyzed for expression of TAMs in biopsy samples by immunohistochemistry. We examined TAM subsets and their production of immune suppressive molecules (IL-10 and PD-L1) in peripheral blood mononuclear cells from three OSCC patients by flow cytometry. CD163 was detected around the tumor or connective tissue, while CD204 was detected in/around the tumors. Flow cytometric analysis revealed that CD163+CD204+ TAMs strongly produced IL-10 and PD-L1 in comparison with CD163+CD204- and CD163-CD204+ TAMs. Furthermore, the number of activated CD3+ T cells after co-culture with CD163+CD204+ TAMs was significantly lower than that after co-culture with other TAM subsets. In clinical findings, the number of CD163+CD204+ TAMs was negatively correlated with that of CD25+ cells and 5-year progression-free survival. These results suggest that CD163+CD204+ TAMs possibly play a key role in the invasion and metastasis of OSCC by T-cell regulation via IL-10 and PD-L1 production.


Assuntos
Antígenos CD/metabolismo , Antígenos de Diferenciação Mielomonocítica/metabolismo , Antígeno B7-H1/metabolismo , Carcinoma de Células Escamosas/metabolismo , Interleucina-10/metabolismo , Macrófagos/metabolismo , Neoplasias Bucais/metabolismo , Receptores de Superfície Celular/metabolismo , Receptores Depuradores Classe A/metabolismo , Linfócitos T/imunologia , Idoso , Idoso de 80 Anos ou mais , Apoptose , Biomarcadores Tumorais/metabolismo , Complexo CD3/metabolismo , Carcinoma de Células Escamosas/imunologia , Carcinoma de Células Escamosas/patologia , Técnicas de Cocultura , Feminino , Humanos , Terapia de Imunossupressão , Masculino , Pessoa de Meia-Idade , Neoplasias Bucais/imunologia , Neoplasias Bucais/patologia , Análise Multivariada , Prognóstico , Intervalo Livre de Progressão , Resultado do Tratamento , Adulto Jovem
14.
PLoS One ; 12(3): e0173017, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28278185

RESUMO

Oral lichen planus (OLP) is a chronic inflammatory disease characterized by subepithelial T-cell infiltration. Recent studies reported that specific T helper (Th) subsets, especially Th2 cells, are involved in the pathogenesis of OLP. Thymic stromal lymphopoietin (TSLP) is mainly secreted by epithelial cells and potently activates myeloid dendritic cells (mDCs) to induce Th2-mediated inflammation. Here, we investigated the expression of TSLP and related molecules in OLP. Buccal mucosa specimens from patients with OLP, hyperkeratosis, and ulcer were analyzed by immunohistochemistry for expression of TSLP, its receptor (TSLPR), and inflammatory cells. TSLP was detected in/around the epithelium of patients with OLP and hyperkeratosis, whereas TSLPR, CD11c (mDC), and GATA3 (Th2) were strongly expressed in the subepithelial layer only in OLP patients. Double immunofluorescence staining showed that TSLPR expression mainly co-localized with CD11c. Moreover, the number of CD11c- and GATA-3 positive cells was correlated in OLP patients. In lesions selectively extracted by laser microdissection, the mRNA expression of Th2 (IL-4, MDC, TARC, GATA3)- and Th17 (IL-17, RORγt)-related molecules in OLP patients was significantly higher than in other groups. These results suggest that CD11c+ mDCs expressing TSLPR contribute to aberrant Th2 immune responses and the pathogenesis of OLP via TSLP stimulation.


Assuntos
Citocinas/metabolismo , Células Dendríticas/metabolismo , Líquen Plano Bucal/patologia , Células Th2/metabolismo , Idoso , Medula Óssea/metabolismo , Medula Óssea/patologia , Antígeno CD11c/metabolismo , Células Dendríticas/citologia , Feminino , Fator de Transcrição GATA3/genética , Fator de Transcrição GATA3/metabolismo , Humanos , Imuno-Histoquímica , Interleucina-17/genética , Interleucina-17/metabolismo , Interleucina-4/genética , Interleucina-4/metabolismo , Masculino , Pessoa de Meia-Idade , Mucosa Bucal/efeitos dos fármacos , Mucosa Bucal/metabolismo , Mucosa Bucal/patologia , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/genética , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/metabolismo , RNA Mensageiro/metabolismo , Receptores de Citocinas/metabolismo , Células Th17/citologia , Células Th17/imunologia , Células Th17/metabolismo , Células Th2/citologia , Células Th2/imunologia , Linfopoietina do Estroma do Timo
15.
Sci Rep ; 6: 28110, 2016 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-27305838

RESUMO

Oral candidiasis is closely associated with changes in oral fungal biodiversity and is caused primarily by Candida albicans. However, the widespread use of empiric and prophylactic antifungal drugs has caused a shift in fungal biodiversity towards other Candida or yeast species. Recently, next-generation sequencing (NGS) has provided an improvement over conventional culture techniques, allowing rapid comprehensive analysis of oral fungal biodiversity. In this study, we used NGS to examine the oral fungal biodiversity of 27 patients with pseudomembranous oral candidiasis (POC) and 66 healthy controls. The total number of fungal species in patients with POC and healthy controls was 67 and 86, respectively. The copy number of total PCR products and the proportion of non-C. albicans, especially C. dubliniensis, in patients with POC, were higher than those in healthy controls. The detection patterns in patients with POC were similar to those in controls after antifungal treatment. Interestingly, the number of fungal species and the copy number of total PCR products in healthy controls increased with aging. These results suggest that high fungal biodiversity and aging might be involved in the pathogenesis of oral candidiasis. We therefore conclude that NGS is a useful technique for investigating oral candida infections.


Assuntos
Candida albicans/classificação , Candida glabrata/classificação , Candida tropicalis/classificação , Candidíase Bucal/microbiologia , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Tipagem Molecular/métodos , Técnicas de Tipagem Micológica/métodos , Adulto , Biodiversidade , Candida albicans/genética , Candida glabrata/genética , Candida tropicalis/genética , DNA Intergênico/genética , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , RNA Ribossômico 16S/genética
16.
J Phys Chem B ; 117(50): 16212-8, 2013 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-24283848

RESUMO

Stable geometries and stabilization energies (Eform) of the alkali metal complexes with bis(fluorosulfonyl)amide, (fluorosulfonyl)(trifluoromethylslufonyl)amide and bis(trifluoromethylsulfonyl)amide (FSA(-), FTA(-) and TFSA(-)) were studied by ab initio molecular orbital calculations. The FSA(-) complexes prefer the bidentate structures in which two oxygen atoms of two SO2 groups have contact with the metal cation. The FTA(-) and TFSA(-) complexes with Li(+) and Na(+) prefer the bidentate structures, while the FTA(-) and TFSA(-) complexes with Cs(+) prefer tridentate structures in which the metal cation has contact with two oxygen atoms of an SO2 group and one oxygen atom of another SO2 group. The two structures are nearly isoenergetic in the FTA(-) and TFSA(-) complexes with K(+) and Rb(+). The magnitude of Eform depends on the alkali metal cation significantly. The Eform calculated for the most stable TFSA(-) complexes with Li(+), Na(+), K(+), Rb(+) and Cs(+) cations at the MP2/6-311G** level are -137.2, -110.5, -101.1, -89.6, and -84.1 kcal/mol, respectively. The viscosity and ionic conductivity of the alkali TFSA molten salts have strong correlation with the magnitude of the attraction. The viscosity increases and the ionic conductivity decreases with the increase of the attraction. The melting points of the alkali TFSA and alkali BETA molten salts also have correlation with the magnitude of the Eform, which strongly suggests that the magnitude of the attraction play important roles in determining the melting points of these molten salts. The anion dependence of the Eform calculated for the complexes is small (less than 2.9 kcal/mol). This shows that the magnitude of the attraction is not the cause of the low melting points of alkali FTA molten salts compared with those of corresponding alkali TFSA molten salts. The electrostatic interactions are the major source of the attraction in the complexes. The electrostatic energies for the most stable TFSA(-) complexes with the five alkali metal cations are -140.3, -119.4, -104.1, -96.9, and -91.1 kcal/mol, respectively. The induction interactions also contribute to the attraction. In particular, the induction interactions are large in the Li(+) complexes. The induction energies for the five complexes are -46.6, -25.2, -17.5, -13.3, and -10.4 kcal/mol, respectively.

17.
J Phys Chem B ; 116(33): 10089-97, 2012 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-22831401

RESUMO

Ionic mobility of electrolyte materials is essentially determined by the nanoscale interactions, the ion-ion interactions and ion-solvent interactions. We quantitatively evaluated the interactive situation of the lithium polymer gel electrolytes through the measurements of ionic conductivity and diffusion coefficients of the mobile species of the lithium polymer electrolytes. The interactive force between the cation and anion in the gel depended on the mixing ratio of the binary solvent, ethylene carbonate plus dimethyl carbonate (EC/DMC). The gel with the solvent (3:7 EC:DMC) showed minimal cation-anion interaction, which is the cause of the highest ionic mobility compared with those of the other gels with different solvents. This suggests that the cation-anion interaction does not simply depend on the dielectric constant of the solvent but is associated with the solvation condition of the lithium. In the case of the gel with the 3:7 EC/DMC solvent, most of the EC species strongly coordinate to a lithium ion, forming the stable solvated lithium, Li(EC)(3)(+), and there are no residual EC species for exchange with them. As a result, the solvating EC species would be a barrier that restricts the anion attack to the lithium leading to the smallest cation-anion interaction. On the other hand, interaction between the cation and polar sites, hydroxyl and oxygen groups of ether of the polyvinyl butyral (PVB) and polyethylene oxide (PEO) polymer, respectively, in the gels was another dominant factor responsible for cation mobility. It increased with increasing polar site concentration per lithium. In case of the PVB gels, cation-anion interaction increased with an increasing polymer fraction of the gel contrary to the independent feature of PEO gels with the change of the polymer fraction. This indicates that the cation-anion interaction is associated with the polymer structure of the gel characterized by the kind and configuration of polar groups, molecular weight, and network morphology of the polymer.


Assuntos
Polietilenoglicóis/química , Polivinil/química , Condutividade Elétrica , Eletrólitos/química , Géis/química , Polivinil/síntese química , Soluções
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