Showing papers on "Ionic conductivity published in 2012"
TL;DR: The effect of Al and Li concentration on the formation of cubic garnet of nominal composition Li 7 La 3 Zr 2 O 12 was investigated in this paper, where it was determined that at least 0.204 moles of Al is required to stabilize the cubic phase.
523 citations
TL;DR: A novel class of solid electrolytes with three-dimensional conducting pathways based on lithium-rich anti-perovskites (LiRAP) with ionic conductivity of σ > 10(-3) S/cm at room temperature and activation energy of 0.2-0.3 eV is presented.
Abstract: Lithium ion batteries have shown great promise in electrical energy storage with enhanced energy density, power capacity, charge–discharge rates, and cycling lifetimes. However common fluid electrolytes consisting of lithium salts dissolved in solvents are toxic, corrosive, or flammable. Solid electrolytes with superionic conductivity can avoid those shortcomings and work with a metallic lithium anode, thereby allowing much higher energy densities. Here we present a novel class of solid electrolytes with three-dimensional conducting pathways based on lithium-rich anti-perovskites (LiRAP) with ionic conductivity of σ > 10–3 S/cm at room temperature and activation energy of 0.2–0.3 eV. As temperature approaches the melting point, the ionic conductivity of the anti-perovskites increases to advanced superionic conductivity of σ > 10–2 S/cm and beyond. The new crystalline materials can be readily manipulated via chemical, electronic, and structural means to boost ionic transport and serve as high-performance s...
420 citations
TL;DR: Although HKUST-1 is neutral, coordinated water molecules are rendered sufficiently acidic by Cu(II) to contribute protons to pore-filling methanol molecules and thereby enhance the alternating-current conductivity, and substantial proton conductivity with the "as synthesized" version of this material is observed.
Abstract: HKUST-1, a metal–organic framework (MOF) material containing CuII-paddlewheel-type nodes and 1,3,5-benzenetricarboxylate struts, features accessible CuII sites to which solvent or other desired molecules can be intentionally coordinated As part of a broader investigation of ionic conductivity in MOFs, we unexpectedly observed substantial proton conductivity with the “as synthesized” version of this material following sorption of methanol Although HKUST-1 is neutral, coordinated water molecules are rendered sufficiently acidic by CuII to contribute protons to pore-filling methanol molecules and thereby enhance the alternating-current conductivity At ambient temperature, the chemical identities of the node-coordinated and pore-filling molecules can be independently varied, thus enabling the proton conductivity to be reversibly modulated The proton conductivity of HKUST-1 was observed to increase by ∼75-fold, for example, when node-coordinated acetonitrile molecules were replaced by water molecules In c
358 citations
TL;DR: It is shown that nanotubes can be packaged within insulating clay layers to form effective 3D nanofillers that increase the lithium ion conductivity of PEO electrolyte by almost 2 orders of magnitude.
Abstract: There is a growing shift from liquid electrolytes toward solid polymer electrolytes, in energy storage devices, due to the many advantages of the latter such as enhanced safety, flexibility, and manufacturability. The main issue with polymer electrolytes is their lower ionic conductivity compared to that of liquid electrolytes. Nanoscale fillers such as silica and alumina nanoparticles are known to enhance the ionic conductivity of polymer electrolytes. Although carbon nanotubes have been used as fillers for polymers in various applications, they have not yet been used in polymer electrolytes as they are conductive and can pose the risk of electrical shorting. In this study, we show that nanotubes can be packaged within insulating clay layers to form effective 3D nanofillers. We show that such hybrid nanofillers increase the lithium ion conductivity of PEO electrolyte by almost 2 orders of magnitude. Furthermore, significant improvement in mechanical properties were observed where only 5 wt % addition of the filler led to 160% increase in the tensile strength of the polymer. This new approach of embedding conducting-insulating hybrid nanofillers could lead to the development of a new generation of polymer nanocomposite electrolytes with high ion conductivity and improved mechanical properties.
258 citations
TL;DR: In this article, the phase formation of cubic tantalum substituted LLZTO ceramics was studied by X-ray powder diffraction, where Ta substitution was found to facilitate the formation of the cubic garnet modification at lower synthesis temperature.
214 citations
TL;DR: In this article, the authors studied the correlation between structure and ion mobility in Li7−xLa3(Zr2−xMx)O12 (x = 0, 0.25; M = Ta5+, Nb5+) combining Molecular Dynamics (MD) simulations, bond valence (BV) studies and experimental characterisation.
Abstract: Due to their favourable combination of high ionic conductivity and stability versus elemental lithium, garnet-related lithium ion conductors Li7La3Zr2O12 have raised strong interest for both all-solid-state batteries and as protective layers for anode materials. Here we study the correlation between structure and ion mobility in Li7−xLa3(Zr2−xMx)O12 (x = 0, 0.25; M = Ta5+, Nb5+) combining Molecular Dynamics (MD) simulations, bond valence (BV) studies and experimental characterisation. In situXRD demonstrates a tetragonal-to-cubic phase transition above 450 K for LixLa3Zr2O12. MD simulations using our new BV-based Morse-type force field reproduce static (lattice constants, thermal expansion, phase transition) and dynamic characteristics of this material. Simulations and structure refinements for the tetragonal phase accordingly yield an ordered Li distribution. The majority of Li fully occupies the 16f and 32g octahedral sites. Out of the two tetrahedral sites only the 8a site is fully occupied leaving the 16e tetrahedral sites with slightly higher site energy due to the tetragonal distortion vacant. For the cubic phase recent structural studies either suggest a major Li+ redistribution to nearly fully occupied tetrahedral sites and distorted octahedral sites with a low occupancy (which leads to unphysically short Li–Li distances) or suggest the existence of additional Li sites. MD simulations however show that the lithium distribution just above the phase transition closely resembles that in the tetragonal phase with only slightly more than 1/3 of the now equivalent tetrahedral 24d sites and almost half of the distorted octahedral 96h sites occupied, so that overly short Li–Li distances are avoided. Pentavalent doping enhances ionic conductivity by increasing the vacancy concentration and by reducing local Li ordering. At higher temperatures Li is gradually redistributed to the tetrahedral sites that can be occupied up to a site occupancy factor of 0.56. BV pathway analysis and closely harmonizing Li trajectories demonstrate that the two partially occupied Li sites of similar site energy form a 3D network suitable for fast ion conduction. The simulated diffusion coefficient and its activation energy closely match the experimental conductivities. The degree of correlation of the vacancy-type Li+ ion migration is analyzed in terms of the van Hove correlation function.
206 citations
TL;DR: A gel polymer electrolyte (GPE) based on an electrospun polymer membrane of poly(acrylonitrile)/poly(methyl methacrylate) (PAN/PMMA) incorporating with a room-temperature ionic liquid N-methy-N-butylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR14TFSI) was prepared and its performance for lithium ion batteries was investigated as discussed by the authors.
178 citations
TL;DR: In this paper, Cubic Li 6.25 La 3 Zr 2 Ga 0.25 O 12 powders were prepared from co-precipitated nitrate precursor and consolidated by hot-pressing to a relative density of ∼91%.
170 citations
TL;DR: In this article, the formation and growth of argyrodite-type Li6PS5X (X = Cl, Br, I) using mechanical milling followed by annealing is investigated.
Abstract: All-solid-state rechargeable lithium-ion batteries (AS-LIBs) are attractive power sources for electrochemical applications due to their potentiality in improving safety and stability over conventional batteries with liquid electrolytes. Finding a solid electrolyte with high ionic conductivity and compatibility with other battery components is a key factor in raising the performance of AS-LIBs. In this work, we prepare argyrodite-type Li6PS5X (X = Cl, Br, I) using mechanical milling followed by annealing. X-ray diffraction characterization reveals the formation and growth of crystalline Li6PS5X in all cases. Ionic conductivity of the order of 7 × 10−4 S cm−1 in Li6PS5Cl and Li6PS5Br renders these phases suitable for AS-LIBs. Joint structure refinements using high-resolution neutron and laboratory X-ray diffraction provide insight into the influence of disorder on the fast ionic conductivity. Besides the disorder in the lithium distribution, it is the disorder in the S2−/Cl− or S2−/Br− distribution that we find to promote ion mobility, whereas the large I− cannot be exchanged for S2− and the resulting more ordered Li6PS5I exhibits only a moderate conductivity. Li+ ion migration pathways in the crystalline compounds are modelled using the bond valence approach to interpret the differences between argyrodites containing different halide ions.
168 citations
TL;DR: In this article, a series of polymerized ionic liquid (PIL) block and random copolymers were synthesized from a nonionic monomer, methyl methacrylate (MMA), at various PIL compositions with the goal of understanding the influence of morphology on ion transport.
Abstract: A series of polymerized ionic liquid (PIL) block and random copolymers were synthesized from an ionic liquid monomer, 1-[(2-methacryloyloxy)ethyl]-3-butylimidazolium bis(trifluoromethanesulfonyl)imide (MEBIm-TFSI), and a nonionic monomer, methyl methacrylate (MMA), at various PIL compositions with the goal of understanding the influence of morphology on ion transport. For the diblock copolymers, the partial affinity between the PIL and PMMA blocks resulted in a weakly microphase-separated morphology with no evident long-range periodic structure across the PIL composition range studied, while the random copolymers revealed no microphase separation. These morphologies were identified with a combination of techniques, including differential scanning calorimetry, small-angle X-ray scattering, and transmission electron microscopy. Surprisingly, at similar PIL compositions, the ionic conductivity of the block copolymers were ca. 2 orders of magnitude higher than the random copolymers despite the weak microphase...
162 citations
TL;DR: In this paper, the effects of PMMA on the morphology, degree of crystallinity, porosity, and electrolyte uptake of the polyvinylidene fluoride (PVDF)/poly(methyl methacrylate) membranes were studied.
TL;DR: In this paper, polysulfone (PSF) backbones were functionalized with reactive chloromethyl groups for preparing thin film anion exchange membranes (AEMs) with fixed benzyl quaternary cations.
Abstract: Polysulfone (PSF) backbones were functionalized with reactive chloromethyl groups for preparing thin film anion exchange membranes (AEMs) with fixed benzyl quaternary cations. Three different cation chemistries of varying basicity were evaluated: 1,4-dimethylpiperazinium (DMP+), trimethylammonium (TMA+), and trimethylphosphonium (TMP+). The water uptake, ionic conductivity, and stability in alkaline media of these AEMs were assessed with both chloride and hydroxide counteranions. The results obtained revealed that the basicity value of the free base conjugate of the functionalized quaternary cations correlated well with gains in ionic conductivity. Cation basicity also correlated well with the alkaline stability of cations with the same inorganic atom, but was not an appropriate heuristic for comparing alkaline stability across cations with different inorganic atoms. The alkaline stability studies indicated that the primal degradation pathway of the TMA+ cation differed from that of the TMP+ cation (direct nucleophilic attack versus ylide formation). PSF with TMA+ and DMP+ cations were demonstrated to show alkaline fuel cell performance that reflected their respective ionic conductivity values.
TL;DR: Drawing together of the analytical and computational techniques has allowed the construction of a transport mechanism for the OIPC diethyl(methyl)(isobutyl)phosphonium hexafluorophosphate, and it is anticipated that utilization of these techniques will allow a more detailed understanding of the transport mechanisms of other plastic crystal electrolyte materials.
Abstract: Understanding the ion transport behavior of organic ionic plastic crystals (OIPCs) is crucial for their potential application as solid electrolytes in various electrochemical devices such as lithium batteries. In the present work, the ion transport mechanism is elucidated by analyzing experimental data (single-crystal XRD, multinuclear solid-state NMR, DSC, ionic conductivity, and SEM) as well as the theoretical simulations (second moment-based solid static NMR line width simulations) for the OIPC diethyl(methyl)(isobutyl)phosphonium hexafluorophosphate ([P1,2,2,4][PF6]). This material displays rich phase behavior and advantageous ionic conductivities, with three solid–solid phase transitions and a highly “plastic” and conductive final solid phase in which the conductivity reaches 10–3 S cm–1. The crystal structure shows unique channel-like packing of the cations, which may allow the anions to diffuse more easily than the cations at lower temperatures. The strongly phase-dependent static NMR line widths o...
TL;DR: In this paper, the authors used X-ray scattering to investigate morphology and dielectric spectroscopy to study ionic conduction and conduction response of imidazolium-based single-ion conductors with two different counterions [hexafluorophosphate (PF6)- or bis(trifluoromethanesulfonyl)imide (F3CSO2NSO2CF3- = Tf2N-], particularly tail length (n-butyl vs n-dodecyl).
Abstract: We use X-ray scattering to investigate morphology and dielectric spectroscopy to study ionic conduction and dielectric response of imidazolium-based single-ion conductors with two different counterions [hexafluorophosphate (PF6–) or bis(trifluoromethanesulfonyl)imide (F3CSO2NSO2CF3– = Tf2N–)] with different imidazolium pendant structures, particularly tail length (n-butyl vs n-dodecyl). A physical model of electrode polarization is used to separate ionic conductivity of the ionomers into number density of conducting ions and their mobility. Tf2N– counterions display higher ionic conductivity and mobility than PF6– counterions, as anticipated by ab initio calculations. Ion mobility is coupled to polymer segmental motion, as these are observed to share the same Vogel temperature. Ionomers with the n-butyl tail impart much larger static dielectric constant than those with the n-dodecyl tail. From the analysis of the static dielectric constant using Onsager theory, there is more ionic aggregation in ionomers ...
TL;DR: It is demonstrated that the fast capacitive process exhibits a Vogel-Fulcher-Tamman temperature dependence, which suggests that the time scale of this process is determined by a temperature-independent barrier, which may be related to structural reorganisations of the Au surface and/or to charge redistributions in the strongly bound innermost ion layer.
Abstract: Ionic liquids are of high interest for the development of safe electrolytes in modern electrochemical cells, such as batteries, supercapacitors and dye-sensitised solar cells. However, electrochemical applications of ionic liquids are still hindered by the limited understanding of the interface between electrode materials and ionic liquids. In this article, we first review the state of the art in both experiment and theory. Then we illustrate some general trends by taking the interface between the extremely pure ionic liquid 1-butyl-1-methylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate and an Au(111) electrode as an example. For the study of this interface, electrochemical impedance spectroscopy was combined with in situ STM and in situ AFM techniques. In addition, we present new results for the temperature dependence of the interfacial capacitance and dynamics. Since the interfacial dynamics are characterised by different processes taking place on different time scales, the temperature dependence of the dynamics can only be reliably studied by recording and carefully analysing broadband capacitance spectra. Single-frequency experiments may lead to artefacts in the temperature dependence of the interfacial capacitance. We demonstrate that the fast capacitive process exhibits a Vogel–Fulcher–Tamman temperature dependence, since its time scale is governed by the ionic conductivity of the ionic liquid. In contrast, the slower capacitive process appears to be Arrhenius activated. This suggests that the time scale of this process is determined by a temperature-independent barrier, which may be related to structural reorganisations of the Au surface and/or to charge redistributions in the strongly bound innermost ion layer.
TL;DR: In this article, the authors applied a new methodology in the force field generation (Phys. Chem.2011, 13, 7910) to study binary mixtures of five imidazolium-based room-temperature ionic liquids (RTILs) with acetonitrile (ACN).
Abstract: We apply a new methodology in the force field generation (Phys. Chem. Chem. Phys.2011, 13, 7910) to study binary mixtures of five imidazolium-based room-temperature ionic liquids (RTILs) with acetonitrile (ACN). Each RTIL is composed of tetrafluoroborate (BF(4)) anion and dialkylimidazolium (MMIM) cations. The first alkyl group of MIM is methyl, and the other group is ethyl (EMIM), butyl (BMIM), hexyl (HMIM), octyl (OMIM), and decyl (DMIM). Upon addition of ACN, the ionic conductivity of RTILs increases by more than 50 times. It significantly exceeds an impact of most known solvents. Unexpectedly, long-tailed imidazolium cations demonstrate the sharpest conductivity boost. This finding motivates us to revisit an application of RTIL/ACN binary systems as advanced electrolyte solutions. The conductivity correlates with a composition of ion aggregates simplifying its predictability. Addition of ACN exponentially increases diffusion and decreases viscosity of the RTIL/ACN mixtures. Large amounts of ACN stabilize ion pairs, although they ruin greater ion aggregates.
TL;DR: The ionic conductivity of the electrolytes was found to decrease with increasing salt concentration, with the effect being greater at the higher temperature, and the contribution of Li(+) to ionic Conductivity does not increase proportionally toLi(+) concentration but saturates at higher doping levels.
Abstract: Molecular dynamics simulations of N-methyl-N-propylpyrrolidinium (pyr(13)) bis(trifluoromethanesulfonyl)imide (Ntf(2)) ionic liquid [pyr(13)][Ntf(2)] mixed with [Li][Ntf(2)] salt have been conducted using a polarizable force field. Mixture simulations with lithium salt mole fractions between 0% and 33% at 363 and 423 K yield densities, ion self-diffusion coefficients, and ionic conductivities in very good agreement with available experimental data. In all investigated electrolytes, each Li(+) cation was found to be coordinated, on average, by 4.1 oxygen atoms from surrounding anions. At lower concentrations (x ≤ 0.20), the Li(+) cation was found to be, on average, coordinated by slightly more than three Ntf(2) anions with two anions contributing a single oxygen atom and one anion contributing two oxygen atoms to Li(+) coordination. At the highest [Li][Ntf(2)] concentration, however, there were, on average, 3.5 anions coordinating each Li(+) cation, corresponding to fewer bidendate and more monodentate anions in the Li(+) coordination sphere. This trend is due to increased sharing of anions by Li(+) at higher salt concentrations. In the [pyr(13)][Ntf(2)]/[Li][Ntf(2)] electrolytes, the ion diffusivity is significantly smaller than that in organic liquid electrolytes due to not only the greater viscosity of the solvent but also the formation of clusters resulting from sharing of anions by Li(+) cations. The ionic conductivity of the electrolytes was found to decrease with increasing salt concentration, with the effect being greater at the higher temperature. Finally, we found that the contribution of Li(+) to ionic conductivity does not increase proportionally to Li(+) concentration but saturates at higher doping levels.
TL;DR: In this paper, Li7−xLa3Zr2−xTaxO12 (x = 0−2) was synthesized by the solid state reaction and characterized by the powder X-ray diffraction and the impedance spectroscopy.
Abstract: Lithium garnet oxides of the composition series Li7−xLa3Zr2−xTaxO12 (x = 0−2) were synthesized by the solid state reaction and characterized by the powder X-ray diffraction and the impedance spectroscopy. Single cubic phases were obtained between x = 0.2 and 2, while the end-member Li7La3Zr2O12 exhibited a tetragonal phase. The lattice parameters of the cubic series followed the Vegard’s law. The maximum bulk (9.6 × 10−4 S/cm) and total (6.9 × 10−4 S/cm) conductivities were achieved at x = 0.3 and x = 0.2, respectively at room temperature. Electrochemical tests with a hybrid solid|liquid electrolyte configuration were performed to evaluate the electrochemical performance of the solid electrolytes. © 2012 The Electrochemical Society. [DOI: 10.1149/2.024205esl] All rights reserved.
TL;DR: In this paper, the properties of ceramic and polymer electrolytes are reviewed and a comparison of the results reported in the literature for different electrolyte materials is provided. But the focus is on discussion of the ionic conductivities.
TL;DR: The analysis shows that the ionic conductivity can be decoupled from segmental dynamics and the strength of the decoupling correlates with the fragility but not with the glass transition temperature, prompting a revision of the current picture of ionic transport in polymer electrolytes.
Abstract: We present detailed studies of the relationship between ionic conductivity and segmental relaxation in polymer electrolytes. The analysis shows that the ionic conductivity can be decoupled from segmental dynamics and the strength of the decoupling correlates with the fragility but not with the glass transition temperature. These results call for a revision of the current picture of ionic transport in polymer electrolytes. We relate the observed decoupling phenomenon to frustration in packing of rigid polymers, where the loose local structure is also responsible for the increase in their fragility.
TL;DR: In this paper, a series of comblike peptoid homopolymers with ethylene oxide (EO)n side chains of varying length were synthesized by a rapid solid phase synthetic method.
Abstract: Polymer electrolytes offer great potential for application in lithium batteries. In order to systematically optimize the performance of these materials, atomic level synthetic control over the polymer chemical structure is desired. In this study, we designed a series of chemically defined, monodisperse peptoid polymers to explore the impact of side-chain structure on the thermal and electrical properties. A series of comblike peptoid homopolymers with ethylene oxide (EO)n side chains of varying length were synthesized by a rapid solid phase synthetic method. The electrical properties of these materials with dissolved lithium salt were characterized by ac impedance. The temperature dependence of the ionic conductivity of the polypeptoid electrolytes is consistent with the Vogel–Tamman–Fulcher equation. The optimum ionic conductivity of 2.6 × 10–4 S/cm achieved for oligo-N-2-(2-(2-methoxyethoxy)ethoxy)ethylglycine–Li salt complex at 100 °C, is approximately 10-fold lower than the analogous PEO–salt complex....
TL;DR: Based on Einstein-Smoluchowski relations, dielectric spectra of ionic liquids are used to determine diffusion coefficients in quantitative agreement with independent pulsed field gradient nuclear magnetic resonance measurements, but spanning a broader range of more than 10 orders of magnitude.
Abstract: Ionic liquids (ILs) exhibit unique features such as low melting points, low vapor pressures, wide liquidus temperature ranges, high thermal stability, high ionic conductivity, and wide electrochemical windows As a result, they show promise for use in variety of applications: as reaction media, in batteries and supercapacitors, in solar and fuel cells, for electrochemical deposition of metals and semiconductors, for protein extraction and crystallization, and many others Because of the ease with which they can be supercooled, ionic liquids offer new opportunities to investigate long-standing questions regarding the nature of the dynamic glass transition and its possible link to charge transport Despite the significant steps achieved from experimental and theoretical studies, no generally accepted quantitative theory of dynamic glass transition to date has been capable of reproducing all the experimentally observed features In this Account, we discuss recent studies of the interplay between charge transport and glassy dynamics in ionic liquids as investigated by a combination of several experimental techniques including broadband dielectric spectroscopy, pulsed field gradient nuclear magnetic resonance, dynamic mechanical spectroscopy, and differential scanning calorimetry Based on EinsteinSmoluchowski relations, we use dielectric spectra of ionic liquids to determine diffusion coefficients in quantitative agreement with independent pulsed field gradientmore » nuclear magnetic resonance measurements, but spanning a broader range of more than 10 orders of magnitude This approach provides a novel opportunity to determine the electrical mobility and effective number density of charge carriers as well as their types of thermal activation from the measured dc conductivity separately We also unravel the origin of the remarkable universality of charge transport in different classes of glass-forming ionic liquids« less
TL;DR: In this article, a pulsed laser deposition (PLD) method was used to enhance the electrochromic properties of anodically colored NiO thin films by growing them on FTO/glass substrates.
TL;DR: In this article, the authors employed the bond valence method to identify materials with crystal structures featuring infinite networks of pathways of suitable size that is a prerequisite for fast ion transport, and carried out exhaustive analysis of ~13,000 entries of the Inorganic Crystal Structure Database and ranked the materials based on the fraction of crystal structure space with low bond-valence mismatch.
TL;DR: In this paper, a polyethylene oxide-polyvinyl pyrrolidone (PEO-PVP) blend using solution cast technique was analyzed in order to explore the long range and short-range dynamics of ions.
Abstract: Sodium ion‐conducting polymer blend electrolytes were prepared by dissolving NaCl salt in a polyethylene oxide–polyvinyl pyrrolidone (PEO–PVP) blend using solution cast technique. XRD and FTIR studies confirmed the complexation of the salt with polymer host which leads the reduction of its crystalline nature. FTIR spectra indicate the miscibility between PEO and PVP. Electrical conduction mechanism in the blend polymer complexes has been revealed by employing the complex impedance spectroscopy in the frequency range 1 Hz–1 MHz within the temperature range 303 K–343 K. The total conductivity, dielectric constant and electric modulus of the blend electrolytes are analyzed in order to explore the long range and short‐range dynamics of ions. Ionic conductivity increased with the increase of salt concentration as well as temperature. The dielectric constant showed large value at lower frequencies and increased with temperature indicating polar nature of PEO and PVP of the blend. The electric modulus formalism reveals the non‐Debye nature of the samples. The activation energies responsible for relaxation process measured from modulus spectra are found to be in good agreement with those obtained from dc conductivity studies.
TL;DR: In this article, the authors used TGA, DSC, XRD and ac impedance spectroscopic techniques to characterize polymer electrolyte films of (PVA+15,wt% LiClO 4 )+ x wt% Ionic liquid (IL) 1-ethyl-3-methylimidazolium ethylsulfate [EMIM][EtSO 4 ] ( x =0, 5, 10, 15) were prepared by solution cast technique.
TL;DR: In this article, the structure and ionic conductivity of a lithium-ion conductive glass ceramic (LATP) was studied by means of powder X-ray diffraction, transmission electron microscopy, and broadband impedance spectroscopy.
TL;DR: An experimental and theoretical description of the dissociation equilibrium and transport in a single conical nanopore functionalized with pH-sensitive carboxylic acid groups and phosphonic acid chains and the I-V curves of the asymmetric nanopore are presented.
Abstract: Calcium binding to fixed charge groups confined over nanoscale regions is relevant to ion equilibrium and transport in the ionic channels of the cell membranes and artificial nanopores. We present an experimental and theoretical description of the dissociation equilibrium and transport in a single conical nanopore functionalized with pH-sensitive carboxylic acid groups and phosphonic acid chains. Different phenomena are simultaneously present in this basic problem of physical and biophysical chemistry: (i) the divalent nature of the phosphonic acid groups fixed to the pore walls and the influence of the pH and calcium on the reversible dissociation equilibrium of these groups; (ii) the asymmetry of the fixed charge density; and (iii) the effects of the applied potential difference and calcium concentration on the observed ionic currents. The significant difference between the carboxylate and phosphonate groups with respect to the calcium binding is clearly observed in the corresponding current–voltage (I–...
TL;DR: In this paper, the authors investigated the tetragonal to cubic phase transition based on super-valent cation substitution on the 24c site typically occupied by La (3+) in the garnet structure.