Showing papers on "Ionic conductivity published in 2010"
TL;DR: A comprehensive survey of conduction phenomena in all components of a Li-ion cell incorporating theoretical, experimental, and simulation studies is presented in this paper, where the critical results, issues and challenges with respect to ionic and electronic conduction in the cathode, anode and electrolyte are discussed.
1,394 citations
TL;DR: It is shown that when immersed in an ionic solution, a layer of graphene becomes a new electrochemical structure that is called a trans-electrode, which is an ideal substrate for very high resolution, high throughput nanopore-based single-molecule detectors.
Abstract: Isolated, atomically thin conducting membranes of graphite, called graphene, have recently been the subject of intense research with the hope that practical applications in fields ranging from electronics to energy science will emerge. The atomic thinness, stability and electrical sensitivity of graphene motivated us to investigate the potential use of graphene membranes and graphene nanopores to characterize single molecules of DNA in ionic solution. Here we show that when immersed in an ionic solution, a layer of graphene becomes a new electrochemical structure that we call a trans-electrode. The trans-electrode's unique properties are the consequence of the atomic-scale proximity of its two opposing liquid-solid interfaces together with graphene's well known in-plane conductivity. We show that several trans-electrode properties are revealed by ionic conductance measurements on a graphene membrane that separates two aqueous ionic solutions. Although our membranes are only one to two atomic layers thick, we find they are remarkable ionic insulators with a very small stable conductance that depends on the ion species in solution. Electrical measurements on graphene membranes in which a single nanopore has been drilled show that the membrane's effective insulating thickness is less than one nanometre. This small effective thickness makes graphene an ideal substrate for very high resolution, high throughput nanopore-based single-molecule detectors. The sensitivity of graphene's in-plane electronic conductivity to its immediate surface environment and trans-membrane solution potentials will offer new insights into atomic surface processes and sensor development opportunities.
1,327 citations
TL;DR: The methodologies used to assess the ionic nature in ILs, their dependence on ionic structure, polarity scales, and physicochemical properties is reviewed and the ionicity of certain ILs is predicted from their physic biochemical properties.
Abstract: Ionic liquids (ILs) are ambient temperature molten salts that have attracted considerable attention because of their negligible volatility, thermal stability, nonflammability, and high ionic conductivity. These remarkable properties result essentially from their ionic nature. Thus, the concept of ionicity of ILs (i.e. how ionic they are) is of great significance for characterising their properties. Here, we show the methodologies used to assess the ionic nature in ILs. On the basis of quantitative estimation of the ionicity, their dependence on ionic structure, polarity scales, and physicochemical properties is reviewed. The ionicity of certain ILs is also predicted from their physicochemical properties. The effects of different classes of ILs (e.g., protic ILs and lithium ILs) and binary systems consisting of ILs and other components on the ionicity are also discussed.
461 citations
TL;DR: The surface electrochemistry in ILs is presented, and the interfacial structures of IL/electrode and heterogeneous electron-transfer kinetics are detailed and the updated researches on the electrochemical applications of ILs such as electrode deposition, electrosynthesis, electrocatalysis, electro chemical biosensing, electrochemical capacitor and lithium batteries are demonstrated.
Abstract: Ionic liquids (IL) are widely used in electrochemistry due to their excellent properties such as good ionic conductivity, wide electrochemical potential window, high viscosity, high thermal stability, wide liquid range and tunable solvent properties. In electrochemistry, the performance of an electrochemical system is dependent on the properties of the interface at the IL/electrode. This review presents the surface electrochemistry in ILs, and the interfacial structures of IL/electrode and heterogeneous electron-transfer kinetics are detailed. Finally, the updated researches on the electrochemical applications of ILs such as electrode deposition, electrosynthesis, electrocatalysis, electrochemical biosensing, electrochemical capacitor and lithium batteries are demonstrated.
309 citations
TL;DR: Garnets are capable of accommodating an excess of lithium cations beyond that normally found in this prototypical structure and this excess lithium is found in a mixture of coordination environments with considerable positional and occupational disorder and leads to ionic conductivity of up to 4 × 10−4 S cm−1 at room temperature as discussed by the authors.
Abstract: Garnets are capable of accommodating an excess of lithium cations beyond that normally found in this prototypical structure. This excess lithium is found in a mixture of coordination environments with considerable positional and occupational disorder and leads to ionic conductivity of up to 4 × 10−4 S cm−1 at room temperature. This high value for total conductivity, combined with excellent thermal and (electro)chemical resistance makes these candidate materials for operation in all solid-state batteries. This review looks at garnets with a wide range of stoichiometries and lithium concentrations and the impact of complex lithium distributions and crystallographic order/disorder transitions on the transport properties of these materials.
225 citations
TL;DR: In this article, Li/LiFePO 4 cells with PVdF-HFP composite membranes swollen with a solution of LiTFSI in ether-functionalized pyrrolidinium-imide ionic liquid (PYRA 12O1 TFSI).
209 citations
TL;DR: In this article, a novel thermally and electrochemically stable sodium ion conducting gel polymer electrolyte has been reported, which comprises a solution of NaCF3SO3 (sodium triflate or NaTf) in a room temperature ionic liquid 1-ethyl 3-methyl imidazolium trifluoro-methane sulfonate (EMI-triflate) immobilized in poly (vinylidine fluoride-co-hexafluoropropylene) (PVdF-HFP).
203 citations
TL;DR: In this paper, the authors developed a technique to design and optimize cathode system based directly on the relationships among ionic and electronic conductivities and specific energy, for a range of commercially viable cathode electrochemistries and additives.
202 citations
TL;DR: It is shown here that magnetic fields can be used in a very simple and scalable manner to produce highly aligned hexagonally packed cylindrical microdomains in such membranes over macroscopic areas.
Abstract: The self-assembly of diblock copolymers provides a convenient route to the formation of mechanically robust films with precise and tunable periodic arrangements of two physically demixed but chemically linked polymeric materials. Chemoselective transport membranes may be realized from such films by selective partitioning of an active species into one of the polymer domains. Here, lithium ions were selectively sequestered within the poly(ethylene oxide) block of a liquid crystalline diblock copolymer to form polymer electrolyte membranes. Optimization of the membrane conductivity mandates alignment of self-assembled structures such that conduction occurs via direct as opposed to tortuous transport between exterior surfaces. We show here that magnetic fields can be used in a very simple and scalable manner to produce highly aligned hexagonally packed cylindrical microdomains in such membranes over macroscopic areas. We systematically explore the dependence of the ionic conductivity of the membrane on both temperature and magnetic field strength. A surprising order of magnitude increase in conductivity relative to the nonaligned case is found in films aligned at the highest magnetic field strengths, 6 T. The conductivity of field aligned samples shows a nonmonotonic dependence on temperature, with a marked decrease on heating in the proximity of the order-disorder transition of the system before increasing again at elevated temperatures. The data suggest that domain-confined transport in hexagonally packed cylindrical systems differs markedly in anisotropy by comparison with lamellar systems.
192 citations
TL;DR: The current strong interest in ionic liquids is motivated by their unique combination of properties such as negligible vapour pressure, thermal stability, non-flammability, high ionic conductivity and wide electrochemical stability window.
186 citations
TL;DR: In this article, the different composition of PVA-LiCF 3 SO 3 polymer electrolyte has been prepared by solution cast technique using DMSO as solvent and the FTIR study confirms the polymer-salt complex formation.
Abstract: The development of polymeric systems with high ionic conductivity is one of the main objectives in Li rechargeable battery. In the present study, the different composition of PVA–LiCF 3 SO 3 polymer electrolyte has been prepared by solution cast technique using DMSO as solvent. The FTIR study confirms the polymer–salt complex formation. The amorphous nature of the polymer has been confirmed by XRD analysis. DSC measurements show decrease in T g with increasing salt concentration. The temperature dependent conductivity obeys Arrhenius relationship. The maximum conductivity has been observed in the order of 7 × 10 − 4 S cm − 1 for 25 mol% of LiCF 3 SO 3 . The activation energy has been found to be 0.16 eV. The two peaks have been observed in the dielectric loss spectrum which shows two types of relaxation α and β.
TL;DR: In this article, a proton-conducting polymer electrolyte based on starch and ammonium nitrate (NH4NO3) has been prepared through solution casting method, and the amount of NH4 NO3 was found to influence the proton conduction; the highest obtainable room temperature conductivity was 2.83 × 10−5 S cm−1.
Abstract: A proton-conducting polymer electrolyte based on starch and ammonium nitrate (NH4NO3) has been prepared through solution casting method. Ionic conductivity for the system was conducted over a wide range of frequency between 50 Hz and 1 MHz and at temperatures between 303 K and 373 K. Impedance analysis shows that sample with 25 wt.% NH4NO3 has a smaller bulk resistance (Rb) compared to that of the pure sample. The amount of NH4NO3 was found to influence the proton conduction; the highest obtainable room temperature conductivity was 2.83 × 10−5 S cm−1, while at 100 °C, the conductivity in found to be 2.09 × 10−4 S cm−1. The dielectric analysis demonstrates a non-Debye behavior. Transport parameters of the samples were calculated using the Rice and Roth model and thus shows that the increase in conductivity is due to the increase in the number of mobile ions.
TL;DR: In this article, the authors used X-ray diffraction, Fourier transformed infra-red and scanning electron microscopy to examine ion/filler polymer interaction and the possible changes in the texture of the host polymer due to liquid electrolyte entrapment and the dispersion of SiO2 nanoparticles.
TL;DR: The crystal structure, thermal stability, ionic conductivity, and reactivity of these new phases toward Li and Na have been investigated, and NaFeSO(4)F is the only one to present some redox activity (Fe(2+)/Fe(3+)) toward Li at 3.6 V.
Abstract: We have recently reported a promising 3.6 V metal fluorosulphate (LiFeSO4F) electrode, capable of high capacity, rate capability, and cycling stability. In the current work, we extend the fluorosulphate chemistry from lithium to sodium-based systems. In this venture, we have reported the synthesis and crystal structure of NaMSO4F candidates for the first time. As opposed to the triclinic-based LiMSO4F phases, the NaMSO4F phases adopt a monoclinic structure. We further report the degree and possibility of forming Na(Fe1−xMx)SO4F and (Na1−xLix)MSO4F (M = Fe, Co, Ni) solid-solution phases for the first time. Relying on the underlying topochemical reaction, we have successfully synthesized the NaMSO4F, Na(Fe1−xMx)SO4F, and (Na1−xLix)MSO4F products at a low temperature of 300 °C using both ionothermal and solid-state syntheses. The crystal structure, thermal stability, ionic conductivity, and reactivity of these new phases toward Li and Na have been investigated. Among them, NaFeSO4F is the only one to present...
TL;DR: In this paper, the ionic conductivity was found to be greatly dependent on the concentration of KOH and the interpenetrated polyvinylpyrrolidone in the PVA matrix.
TL;DR: In this article, an attempt to prepare high ionic conductivity lithium polymer electrolytes by UV cross-linking the poly(ethyleneoxide) (briefly called PEO) polymer matrix in presence of the plasticizing lithium salt, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and an ionic liquid of the pyrrolidinium family (N-alkyl-N-methylpyrrolinium TFSI) having a common anion with the lithium salt was reported.
TL;DR: Very high lateral ionic conductivities in epitaxial cubic yttria-stabilized zirconia (YSZ) synthesized on single-crystal SrTiO3 and MgO substrates by reactive direct current magnetron sputtering are reported in this paper.
Abstract: Very high lateral ionic conductivities in epitaxial cubic yttria-stabilized zirconia (YSZ) synthesized on single-crystal SrTiO3and MgO substrates by reactive direct current magnetron sputtering are reported. Superionic conductivities (i.e., ionic conductivities of the order similar to 1 Omega(-1)cm(-1)) are observed at 500 degrees C for 58-nm-thick films on MgO. The results indicate a superposition of two parallel contributions - one due to bulk conductivity and one attributable to conduction along the film substrate interface. Interfacial effects dominate the conductivity at low temperatures (andlt;350 degrees C), showing more than three orders of magnitude enhancement compared to bulk YSZ. At higher temperatures, a more bulk-like conductivity is observed. The films have a negligible grain-boundary network, thus ruling out grain boundaries as a pathway for ionic conduction. The observed enhancement in lateral ionic conductivity is caused by a combination of misfit dislocation density and elastic strain in the interface. These very high ionic conductivities in the temperature range 150-500 degrees C are of great fundamental importance but may also be technologically relevant for low-temperature applications.
TL;DR: In this article, an ionic liquid gel electrolyte membrane was obtained by soaking a fibrous fully interconnected membrane, made of electrospun P(VdF-HFP), in the electrolyte.
TL;DR: In this paper, the best ionic conductivity has been obtained for the samples containing a concentration of 50 ¼wt.% of acetic acid, which exhibits an Arrhenius behavior increasing from 1.1 −1 −4 S/cm at room temperature to 9.6 −4 ǫ S/ǫ cm at 80 −°C.
TL;DR: In this article, the dielectric response of hard and soft Pb(Zr0.58Ti0.42)1−xMexO3 (Me=Fe or Nb) ceramics was studied at subswitching conditions over a wide range of temperatures (50 −450°C) and frequencies (10 mHz to 10 kHz).
Abstract: The dielectric response of hard (Fe-doped) and soft (Nb-doped) rhombohedral Pb(Zr0.58Ti0.42)1−xMexO3 (Me=Fe or Nb) ceramics was studied at subswitching conditions over a wide range of temperatures (50–450 °C) and frequencies (10 mHz to 10 kHz). The results show qualitative differences in the behavior of the acceptor- and donor-doped samples. Hard materials exhibit a steep increase in the complex permittivity with decreasing frequency. The onset of the dispersion is thermally activated with activation energies of about 0.6–0.8 eV and is attributed here to oxygen vacancy hopping. The activation energy for ac conductivity observed in soft materials is estimated to be about 1.7 eV, corresponding to half of the energy gap of Pb(Zr,Ti)O3 and is thus consistent with electronic conduction. The relevance of ionic hopping conductivity in hard materials to ferroelectric aging/deaging and hardening is analyzed. Strong ionic conductivity in hard samples and its absence in soft samples agree well with the dipolar mecha...
TL;DR: In this article, the performance of a composite electrolyte composed of a samarium doped ceria (SDC) and a binary eutectic carbonate melt phase has been examined.
TL;DR: In this paper, the authors report synthesis, characterization, and electrochemical properties of nanocomposite polymer electrolytes (NCPEs) comprising of a RTIL [ n -butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (BMITFSI)] and nano-sized ceramic fillers (SiO 2, Al 2 O 3 or BaTiO 3 ) hosted in electrospun poly(vinylidene fluoride- cohexafluoropropylene) [P(V
Abstract: A solid polymer electrolytes (SPE) comprising blend of poly(ethylene oxide; PEO) and epoxidized natural rubber as a polymer host and LiCF3SO3 as a dopant were prepared by solution-casting technique. The SPE films were characterized by field emission scanning electron microscopy to determine the surface morphology, X-ray diffraction, and differential scanning calorimeter to determine the crystallinity and thermogravimetric analysis to confirm the mass decrease caused by loss of the solvent. While the presence of the complexes was investigated by reflection Fourier transform infrared (ATR-FTIR) spectroscopy. Electrochemical impedance spectroscopy was conducted to obtain ionic conductivity. Scanning electron microscopy analysis showed that a rough surface morphology of SPE became smoother with addition of salt, while ATR-FTIR spectroscopy analysis confirmed the polymer salt complex formation. The interaction occurred between the salt, and ether group of polymer host where the triple peaks of ether group in PEO merged and formed one strong peak at 1,096 cm−1. Ionic conductivity was found to increase with the increase of salt concentration in the polymer blend complexes. The highest conductivity achieved was 1.4 × 10−4 Scm−1 at 20 wt.% of LiCF3SO3, and this composition exhibited an Arrhenius-like behavior with the activation energy of 0.42 eV and the preexponential factor of 1.6 × 103 Scm−1.
TL;DR: In this paper, a specific formulation of the LAGP [Li 1+ x Al x Ge 2− x (PO 4 ) 3 ( x ǫ = 0.5)] glass was chosen.
TL;DR: In this paper, a solution casting technique was used to produce poly(vinylidenefluoride-hexafluoropropylene) (PVdF-HFP) with LiTf as the host, lithium trifluoromethanesulfonate (LiTf) as the salt and ethylene carbonate (EC) as a plasticizer.
TL;DR: In this paper, a composite electrolyte containing a Li/Na carbonate eutectic and a doped ceria phase is employed in a direct carbon fuel cell (DCFC).
TL;DR: In this paper, Li 3 PO 4 thin films have been prepared by pulsed laser deposition (PLD) as a solid electrolyte for thin-film batteries and their structure, composition, ionic conductivity, and electrochemical stability have been characterized.
Abstract: High quality Li 3 PO 4 thin films have been prepared by pulsed laser deposition (PLD) as a solid electrolyte for thin-film batteries. The structure, composition, ionic conductivity, and electrochemical stability of the Li 3 PO 4 thin films have been characterized. The Li 3 PO 4 film exhibits a single lithium-ion conductor with an ionic conductivity of 4.0 × 10 -7 S cm -1 at 25°C and an activation energy of 0.58 eV. The Li 3 PO 4 film is electrochemically stable in the potential range from 0 to 4.7 V vs Li/Li + . All-solid-state thin-film batteries, Li/Li 3 PO 4 /LiCoO 2 , have been fabricated by using PLD-grown Li 3 PO 4 thin film. The thin-film battery shows excellent intercalation property and stability for long-term cycling in the potential range from 3.0 to 4.4 V.
TL;DR: D density-functional calculations are reported that trace the origin of the discovery ofossal room-temperature ionic conductivity in multilayers of yttria-stabilized zirconia and SrTiO3 to a combination of lattice-mismatch strain and O-sublattice incompatibility.
Abstract: Oxide ionic conductors typically operate at high temperatures, which limits their usefulness. Colossal room-temperature ionic conductivity was recently discovered in multilayers of yttria-stabilized zirconia (YSZ) and SrTiO3. Here we report density-functional calculations that trace the origin of the effect to a combination of lattice-mismatch strain and O-sublattice incompatibility. Strain alone in bulk YSZ enhances O mobility at high temperatures by inducing extreme O disorder. In multilayer structures, O-sublattice incompatibility causes the same extreme disorder at room temperature.
TL;DR: In this paper, Fourier Transform-infrared (FT-IR) spectroscopy and X-ray diffraction (XRD) were used to study the complexation between the salt and polymer.
TL;DR: In this paper, tailor-made gel polymer electrolytes based on blend/composite membranes of poly(vinylidene fluoride-co-hexafluoropropylene) and polyacrylonitrile are prepared by electrospinning using 14-wt% polymer solution in dimethylformamide.