Showing papers on "Ionic conductivity published in 2011"
TL;DR: A lithium superionic conductor, Li(10)GeP(2)S(12) that has a new three-dimensional framework structure that exhibits an extremely high lithium ionic conductivity of 12 mS cm(-1) at room temperature, which represents the highest conductivity achieved in a solid electrolyte, exceeding even those of liquid organic electrolytes.
Abstract: Batteries are a key technology in modern society. They are used to power electric and hybrid electric vehicles and to store wind and solar energy in smart grids. Electrochemical devices with high energy and power densities can currently be powered only by batteries with organic liquid electrolytes. However, such batteries require relatively stringent safety precautions, making large-scale systems very complicated and expensive. The application of solid electrolytes is currently limited because they attain practically useful conductivities (10(-2) S cm(-1)) only at 50-80 °C, which is one order of magnitude lower than those of organic liquid electrolytes. Here, we report a lithium superionic conductor, Li(10)GeP(2)S(12) that has a new three-dimensional framework structure. It exhibits an extremely high lithium ionic conductivity of 12 mS cm(-1) at room temperature. This represents the highest conductivity achieved in a solid electrolyte, exceeding even those of liquid organic electrolytes. This new solid-state battery electrolyte has many advantages in terms of device fabrication (facile shaping, patterning and integration), stability (non-volatile), safety (non-explosive) and excellent electrochemical properties (high conductivity and wide potential window).
3,372 citations
TL;DR: In this paper, Li7−XLa3(Zr2−X, NbX)O12 was synthesized by a solid-state reaction, and their lithium ion conductivity was measured using an AC impedance method at temperatures ranging from 25 to 150°C in air.
511 citations
TL;DR: Stoichiometric copper(I) selenide nanoparticles have been synthesized using the hot injection method and enhanced electronic properties can be explained by the oxidation of Cu(+) and Se(2-) on the nanoparticle surface, ultimately leading to a solid-state conversion of the core from monoclinic Cu(2)Se to cubic Cu(1.8)Se.
Abstract: Stoichiometric copper(I) selenide nanoparticles have been synthesized using the hot injection method. The effects of air exposure on the surface composition, crystal structure, and electronic properties were monitored using X-ray photoelectron spectroscopy, X-ray diffraction, and conductivity measurements. The current−voltage response changes from semiconducting to ohmic, and within a week a 3000-fold increase in conductivity is observed under ambient conditions. The enhanced electronic properties can be explained by the oxidation of Cu+ and Se2− on the nanoparticle surface, ultimately leading to a solid-state conversion of the core from monoclinic Cu2Se to cubic Cu1.8Se. This behavior is a result of the facile solid-state ionic conductivity of cationic Cu within the crystal and the high susceptibility of the nanoparticle surface to oxidation. This regulated transformation is appealing as one could envision using layers of Cu2Se nanoparticles as both semiconducting and conducting domains in optoelectronic...
312 citations
TL;DR: In this article, the transference number of the lithium cation is expected to be unity while the ionic conductivity is kept high, and two different single-ion polymers with a similar final structure were synthesized by two ways, monomer free radical polymerization and polymer modification (PSTFSI) and PSTFSI (b) respectively.
303 citations
TL;DR: In this article, almost 300 papers about ionic liquid-modified electrodes were published and they are reviewed here and they can be classified into three classes: carbon paste electrodes, carbon nanotubes and gel electrodes.
296 citations
TL;DR: In this article, the crystal structures of and phase transitions in the Li3PS4, which is part of the thio-LISICON (LIthium Super Ionic CONductor) family, were studied using high-temperature synchrotron X-ray diffraction measurements and thermal analysis.
266 citations
TL;DR: In this paper, x-ray diffraction analysis carried out at room temperature showed the formation of a single phase compound with a rhombohedral crystal system and the bulk conductivity of the material indicates an Arrhenius type of thermally activated process with three different conduction mechanisms as different activation energies are observed.
Abstract: Polycrystalline powder of (Na0.5Bi0.5)TiO3 (NBT) was prepared by a high-temperature solid-state reaction route. Preliminary x-ray diffraction analysis carried out at room temperature showed the formation of a single phase compound with a rhombohedral crystal system. Scanning electron micrograph reveals the polycrystalline nature of the material with size anisotropy. Dielectric study showed an existence of diffuse phase transition around 300 °C. The ac conductivity spectrum obeyed the Jonscher power law. The temperature dependent pre-exponential factor (A) shows peak and frequency exponent (n) possesses a minimum at transition temperature. The bulk conductivity of the material indicates an Arrhenius type of thermally activated process with three different conduction mechanisms as different activation energies are observed. The hopping charge carriers dominate at low temperature, small polaron and oxygen vacancy dominates at intermediate temperature and ionic conduction at higher temperatures. Studies of impedance spectroscopy indicate that the dielectric relaxation is of non-Debye type. In situ high-temperature Raman spectroscopy shows discontinuous changes in the phonon frequencies across the rhombohedral–tetragonal transition. In addition, anomalous changes in the intensity and the linewidth of a lattice mode are found around 350 °C.
250 citations
TL;DR: In this article, the influence of aluminum on the structure and conductivity of Li 7 La 3 Zr 2 O 12 were investigated by X-ray diffraction (XRD), impedance spectroscopy, scanning electron microscopy (SEM), and thermal dilatometry.
246 citations
TL;DR: In this paper, the results of physical-chemical and electrochemical investigations performed on ternary mixtures of the room temperature ionic liquid (IL) N -butyl- N -methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR 14 TFSI), propylene carbonate (PC), and lithium bis(Trifluorsomethane sulfuronyl), and LiTFSI (LiTFSI) as electrolyte for lithium-ion batteries were investigated.
241 citations
TL;DR: Li et al. as discussed by the authors used argyrodite-type Li6PS5X (X,= Cl, Br, I) using mechanical milling followed by annealing.
Abstract: Rechargeable all-solid-state lithium Li-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. AS-LIBs require a Li-fast ion conductor (FIC) as the solid electrolyte. Finding a solid electrolyte with high ionic conductivity and compatibility with other battery components is a key factor in building high performance AS-LIBs. There have been numerous studies, e.g., on lithium rich sulfide glasses as solid electrolytes. However, the limited current density remains a major obstacle in developing competitive batteries based on the known solid electrolytes. Here we prepare argyrodite-type Li6PS5X (X = Cl, Br, I) using mechanical milling followed by annealing. XRD characterization reveals the formation and growth of Li6PS5X crystals in samples under varying annealing conditions. For Li6PS5Cl an ionic conductivity of the order of 10−4 S/cm is reached at room temperature, which is close to the Li mobility in conventional liquid electrolytes (LiPF6 in various carbonates) and well suitable for AS-LIBs.
235 citations
TL;DR: In this paper, a modified sol-gel Pechini method was used to synthesize Li 7 La 3 Zr 2 O 12 (LLZO) nanopowders from the stoichiometric mixtures of lithium carbonate, lanthanum oxide and zirconium ethoxide.
TL;DR: In this article, the authors used solution casting technique to construct polyethylene oxide (PEO) and polyvinyl pyrrolidone (PVP) polymer blend electrolytes with NaF salt.
Abstract: Sodium ion conducting polymer blend electrolyte films, based on polyethylene oxide (PEO) and polyvinyl pyrrolidone (PVP) complexed with NaF salt, were prepared using solution casting technique. The complexation of the salt with the polymer blend was confirmed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and UV–vis spectroscopy. Electrical conductivity of the films was measured with impedance analyzer in the frequency range of 1 Hz to 1 MHz and in the temperature range of 303–348 K. It was observed that the magnitude of conductivity increased with the increase in the salt concentration as well as the temperature. UV–vis absorption spectra in wavelength region of 200–800 nm were used to evaluate the optical properties like direct and indirect optical energy band gaps, optical absorption edge. The optical band gaps decreased with the increase in Na+ ion concentration. This suggests that NaF, as a dopant, is a good choice to improve the electrical properties of PEO/PVP polymer blend electrolytes.
TL;DR: In this paper, the effects of composition, temperature, and polymer identity on the electrical and viscoelastic properties of block copolymer-based ion gels were investigated, and the response of the gels to ac electric fields below 1 MHz can be represented by a resistor and constant phase element (CPE) series circuit, with a characteristic time corresponding to the establishment of stable electrical double l...
Abstract: The effects of composition, temperature, and polymer identity on the electrical and viscoelastic properties of block copolymer-based ion gels were investigated. Ion gels were prepared through the self-assembly of poly(styrene-b-ethylene oxide-b-styrene) (SOS) and poly(styrene-b-methyl methacrylate-b-styrene) (SMS) triblock copolymers in a room-temperature ionic liquid, 1-ethyl-3-methylimidazolium bis(trifluoromethylsufonyl)imide ([EMI][TFSI]). The styrene end-blocks associate into micelles, whereas the ethylene oxide and methyl methacrylate midblocks are well-solvated by this ionic liquid. The properties of the ion gels were examined over the composition range of 10−50 wt % polymer and temperature range of 25−160 and 25−200 °C for the SOS- and SMS-based gels, respectively. The response of the ion gels to ac electric fields below 1 MHz can be represented by a resistor and constant phase element (CPE) series circuit, with a characteristic time corresponding to the establishment of stable electrical double l...
TL;DR: In this paper, the isolated effect of anion type on the chemical, thermal, and conductive properties of imidazolium-based polymerized ionic liquids (PILs) was investigated.
TL;DR: In this article, Nanocomposite polymer electrolyte solution casting Ceramic filler Ionic conductivity Activation energy is used to generate energy. But the authors focus on the energy consumption of the filler.
TL;DR: In this article, the samarium doped ceria-carbonate (SDC/Na2CO3) nanocomposite systems have shown to be excellent electrolyte materials for low-temperature SOFCs, yet, the conduction mechanism is not well understoo
TL;DR: In this paper, a mixed conducting perovskite materials system, SrTi1-xFexO3-δ, is selected, offering the ability to systematically control both the levels of ionic and electronic conductivity as well as the energy band structure.
Abstract: Identifying the important factors governing the oxygen reduction kinetics at solid oxide fuel cell cathodes is critical for enhanced performance, particularly at reduced temperatures. In this work, a model mixed conducting perovskite materials system, SrTi1–xFexO3–δ, is selected, offering the ability to systematically control both the levels of ionic and electronic conductivity as well as the energy band structure. This, in combination with considerably simplified electrode geometry, serves to demonstrate that the rate of oxygen exchange at the surface of SrTi1–xFexO3–δ is only weakly correlated with either high electronic or ionic conductivity, in apparent contradiction with common expectations. Based on the correlation found between the position of the Fermi energy relative to the conduction band edge and the activation energy exhibited by the exchange rate constant, it is possible to confirm experimentally, for the first time, the key role that the minority electronic species play in determining the overall reaction kinetics. These observations lead to a new conceptual model describing cathode kinetics and provide guidelines for identifying cathodes with improved performance.
TL;DR: In this paper, a solution cast of polyvinyl pyrrolidone (PVP) complexed with different weight percent ratios of KBrO4 salt was prepared by using solution cast technique and the glass transition temperature and relative percentage of crystallinity of these films were determined using differential scanning calorimetry (DSC).
ENEA1
TL;DR: In this article, the chemical properties of hydrophobic ionic liquids, tailored as electrolyte components for supercapacitors and lithium batteries, were investigated and compared, based on bis(perfluroalkylsulfonyl)imide anions coupled with different types of cation.
TL;DR: Being halogen free these hf-BILs offer a more environmentally benign alternative to ILs being currently developed for lubricant applications and are hydrophobic and hydrolytically stable liquids at room temperature.
Abstract: We report on the synthesis, characterisation, and physical and tribological properties of halogen-free ionic liquids based on various chelated orthoborate anions with different phosphonium cations, both without halogen atoms in their structure. Important physical properties of the ILs including glass transition temperatures, density, viscosity and ionic conductivity were measured and are reported here. All of these new halogen-free orthoborate ionic liquids (hf-BILs) are hydrophobic and hydrolytically stable liquids at room temperature. As lubricants, these hf-BILs exhibit considerably better antiwear and friction reducing properties under boundary lubrication conditions for steel-aluminium contacts as compared with fully formulated (15W-50 grade) engine oil. Being halogen free these hf-BILs offer a more environmentally benign alternative to ILs being currently developed for lubricant applications.
TL;DR: In this study, binary mixtures composed of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)-imide, and a selection of six molecular components varying in polarity, size, and isomerism are focused on.
Abstract: In this study, we have focused on binary mixtures composed of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)-imide, [C4C1im][Ntf2], and a selection of six molecular components (acetonitrile, dichloromethane, methanol, 1-butanol, t-butanol, and water) varying in polarity, size, and isomerism. Two Kamlet–Taft parameters, the polarizability π* and the hydrogen bond acceptor β coefficient were determined by spectroscopic measurements. In most cases, the solvent power (dipolarity/polarizability) of the ionic liquid is only slightly modified by the presence of the molecular component unless large quantities of this component are present. The viscosity and electrical conductivity of these mixtures were measured as a function of composition and the relationship between these two properties were studied through Walden plot curves. The viscosity of the ionic liquid dramatically decreases with the addition of the molecular component. This decrease is not directly related to the volumetric properties of ea...
TL;DR: In this article, a corn starch-lithium hexafluorophosphate (LiPF 6 ) based biopolymer electrolytes were prepared by solution casting technique.
Abstract: Biodegradable corn starch–lithium hexafluorophosphate (LiPF 6 ) based biopolymer electrolytes were prepared by solution casting technique. Ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate (BmImPF 6 ) was doped into the polymer matrix. Upon addition of 50 wt.% BmImPF 6 , the maximum ionic conductivity of (1.47 ± 0.02) × 10 − 4 Scm − 1 was achieved due to its higher amorphous region. This result had been further proven in ATR-FTIR study. Frequency dependence of conductivity and dielectric studies reveal the occurrence of polarization at the electrolyte–electrode interface and thus form the electrical double layer, asserting the non-Debye characteristic of polymer electrolytes. This result is in good agreement with dielectric loss tangent study. Based on the changes in shift, changes in intensity, changes in shape and existence of some new peaks, attenuated total reflectance-Fourier Transform Infrared (ATR-FTIR) divulged the complexation between corn starch, LiPF 6 and BmImPF 6 , as shown in the spectra.
TL;DR: Different values for the simultaneous electronic and ionic conductivity of a conjugated polymer containing poly(3-hexylthiophene) and poly(ethylene oxide) (P3HT-PEO) were determined by using ac impedance and dc techniques.
Abstract: Charging ahead: separate values for the simultaneous electronic and ionic conductivity of a conjugated polymer containing poly(3-hexylthiophene) and poly(ethylene oxide) (P3HT-PEO) were determined by using ac impedance and dc techniques. P3HT-PEO was used as binder, and transporter of electronic charge and Li(+) ions in a LiFePO(4) cathode, which was incorporated into solid-state lithium batteries.
TL;DR: Li 7−−x La 3 Zr 2 O 12−−−0.5x (LLZ) ceramics with garnet-type structure were prepared via the conventional solid-state reaction method.
TL;DR: In this paper, a composite polymer electrolyte with a 1-dimensional nanofiller such as SiO 2 nanowires was proposed for practical applications in lithium ion batteries, which can tolerate a maximal stress of 27.8MPa.
TL;DR: In this article, structure property relationships for polymerized ionic liquids (PILs) relate chemical structure to ionic conductivity and reveal the importance of glass transition temperature (Tg) and the energy associated with an ion-hopping mechanism for ion conduction for a series of alkyl-substituted vinylimidazolium PILs.
Abstract: Structure-property relationships for polymerized ionic liquids (PILs) relate chemical structure to ionic conductivity and reveal the importance of glass transition temperature (Tg) and the energy associated with an ion-hopping mechanism for ion conduction for a series of alkyl-substituted vinylimidazolium PILs. The alkyl-substituted vinylimidazolium-based PILs with varying lengths of n-alkyl substituents provide diverse precursors with exchangeable anions to further enhance thermal stability and ionic conductivity. As the anion size increases, regardless of alkyl substituent length, Tg decreases and the onset of weight loss, TD, increases. As the length of the alkyl substituent increases, Tg decreases for PILs with Br− and BF4− counteranions. Ionic conductivity increases over an order of magnitude upon exchange of the counteranion from TfO− < Tf2N−.
TL;DR: In this article, an experimental investigation on a sodium ion conducting gel polymer electrolyte nanocomposite based on poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP), dispersed with silica nanoparticles are reported.
TL;DR: In this paper, a poly(ethylene oxide) (PEO) based polymer electrolyte incorporated with room temperature ionic liquid (RTIL) is reported, which has a maximum electrical conductivity of ∼5.6 × 10−4 −4 S cm−1 at room temperature (∼25 °C) with improved thermal and electrochemical stabilities.
TL;DR: In this paper, the polyethylene oxide (PEO) based lithium ion conducting polymer electrolytes complexed with lithium trifluoromethanesulfonate (LiCF 3 SO 3 or LiTf) plasticized with an ionic liquid 1-ethyl 3-methyl imidazolium triflomeromethane sulfurate (EMITf) have been reported.
TL;DR: In this article, a non-woven membrane of high molecular weight poly(acrylonitrile) (PAN) is demonstrated as an efficient host matrix for the preparation of gel polymer electrolytes for lithium-ion batteries.