Ionic Conductivity

Proton chemistry is a fascinating field with both fundamental and applied aspects. The development of solid-state proton conductors relying on abundant elements could help bring those two aspects. In this scope, we synthesized a disordered structure which, as revealed by the real-space refinement of the pair distribution function, has been identified to be the trititanate arrangement. The layered structure is stabilized by the presence of hydronium ions and water molecules located in the interlayer space. This compound displays a high ionic conductivity of 4•10 -2 S/m with an activation energy of 0.24 eV, assigned to H +mobility as shown by broadband dielectric spectroscopy. Proton mobility was further evidenced by solid-state 1 H NMR. DFTcalculations revealed that proton transfer occurs both within the interlayer space and with terminal oxide of the titanate framework through a Grotthuss-based mechanism rationalizing the high conductivity measured experimentally. Finally, we investigated the electrochemical properties with respect to the proton as a charge carrier using a proton-free (KCl) and proton-donor (buffer acetic acid) electrolytes. The results showed that the structure can reversibly intercalate protons at a very high rate opening exiting perspectives on the development of negative electrode materials for aqueous proton batteries. Overall, this study helps better understanding the proton transfer mechanism occurring in a confined layered type structure.

Solid-state batteries relying on fluoride-ion shuttle are still at their early stage of development. Assessing the fluoride solid electrolyte's electrochemical stability and its conduction properties in a mixture with carbon, as well as the possible interaction of fluoride-ion with carbon both during the

8mol% YSZ is one of the most common electrolytes for a solid oxide fuel cell (SOFC) due to its high stability at high operating temperatures with good electrical properties. In this work, 8mol%YSZ (8YSZ) were prepared via powder technology and doped with a trivalent dopant of Al +3 and quadrant Pb +4 dopant by a less than l mol% to produce two types of electrolytes: γAl2O3-8YSZ and Pb3O4-8YSZ. The majority of this work is to evaluate the ionic conductivity and study the influence of each dopant Al2O3 and Pb3O4 doped 8YSZ sintered electrolyte via electrochemical Impedance spectroscopy (EIS) at different temperatures from 700°C to 800°C. In addition, the morphology of sintered doped electrolytes was studied with Field Energy Scanning Electron Microscopy (FE-SEM). The chemical characterization analysis with Energy-dispersive X-ray spectroscopy (EDX). The phases of the sintered electrolytes examined with X-ray diffraction (XRD). The resultant ionic conductivity at 800°C for γAl2O3-8YSZ electrolyte was 0.412S.cm and for Pb3O4-8YSZ electrolyte was 0.738S.cm with lower activation energy of 0.575 eV and grain size of 7460nm compared with 0.727 eV for γAl2O3-8YSZ electrolyte and grain size of 8449nm. Accordingly, the Pb3O4-8YSZ is a better candidate to use as an electrolyte at high temperatures.

The initiation and propagation of electrochemical degradation in sodium-beta alumina type solid electrolytes has been found to involve grain boundaries. Degradation is preferentially initiated at 00.1 facets of large grains, lowering the critical current density threshold for coarse grained electrolytes. The critical current densities were determined by monitoring acoustic emissions during current flow. Direct indications of the implication of grain boundaries in degradation has been obtained from transmission and optical microscopy of degraded electrolytes • *on leave from the

Sodium-beta alumina solid electrolytes degrade during use in sodium sulfur cells. The degradation can take two forms: Mode I degradation involving the rapid propagation of macroscopic cracks driven by cathodic deposition of sodium in them; and Mode II degradation involving a slow degradation due to electron injection from the Na/..beta.. alumina contact. The initiation stage of Mode I is the most important one since cracks propagate rapidly once they are formed. The significance of the local microstructure on the Mode I initiation is discussed. It appears that grain boundaries can be favorable sites for Mode I failure initiation.

Gel polymer electrolytes are known to be very suitable for many electrochemical devices. They have been extensively studied for lithium based electrochemical cells. But, due to several drawbacks of lithium based cells such as safety issues, handling problems and toxicity, it is the time to develop non Li based cells. In this study, ionic conductivity of a gel polymer electrolyte (GPE) based on polymethylmethacrylate, ethylene carbonate, propylene carbonate and tetrapropylammonium iodide and its performance in an Mg / C: I2 cell was investigated. GPE was prepared by varying salt concentration using hot pressed method and the composition, 20 PMMA / 30 EC / 30 PC / 40 Pr4N + I showed the highest conductivity of 5.02 x 10 -3 Scm -1 at 28  C. The cell in the form Mg / GPE / C+I2 showed an average open circuit voltage of 1.9 V. The average short circuit current was 3.3 mA. It was possible to observe a good stability by the self discharge characteristics of the cell.

Soft solid electrolyte materials are promising alternative choices for conventional battery electrolytes. Here, we have synthesized, characterized and calculated structural, thermal and electrochemical properties of an adiponitrile-based lithium-ion electrolyte which combines the advantages of organic and ceramic materials. This solid material is (Adpn)2LiPF6, (Adpn = adiponitrile) wherein (Adpn)-based channels solvate Li + ions through weak C≡N---Li + contacts. The surface of the crystal is a liquid nanolayer that binds the grains so that ionically conductive pellets are easily formed without high pressure/temperature treatments, which self-heals if fractured and which provide liquid-like conduction paths through the grain boundaries. High conductivity (σ ~ 10 -4 S/cm) and high lithium-ion transference number (tLi + = 0.54) result from weak interactions between "hard" (charge-dense) Li + ions and "soft" (electronically polarizable) -C≡N, compared with the stronger interactions of previously reported "hard" ether oxygen contacts of polyethylene oxide (PEO) or glymes. The proposed mechanism of conduction is one in which Li + ion migration occurs preferentially along the low activation energy path at the co-crystal grain boundaries and within the interstitial regions between the co-crystals, with bulk conductivity comprising a smaller but extant contribution to the observed conductivity. (Adpn)2LiPF6(s) has a wide electrochemical stability window of 0 to 5 V. Li 0 /(Adpn)2LiPF6/LiFePO4 cells exhibit cycling for > 50 cycles at C/20, C/10, C/5 rates with capacities of 140 mAh-g -1 to 100 mAh-g -1 and Coulombic efficiencies ~ 99%, and mitigation of the deleterious reactions with Li metal due to the high ionic strength. LTO/(Adpn)2LiPF6/NMC622 full cells were cycled at C-rates of C/20 to 1C with Coulombic efficiencies > 96%, with no dendritic failure after 100 cycles. Novel MD approaches addressing multiple conduction pathways and PWDFT calculations offer insights into the molecular basis of the physical and conductivity properties.

15. NUMBER OF PAGES 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 5c. PROGRAM ELEMENT NUMBER 5b. GRANT NUMBER 5a. CONTRACT NUMBER Form Approved OMB NO. 0704-0188 3. DATES COVERED (From -To) The Electrochemical Society (ECS) is an international, nonprofit, scientific, educational organization founded for the advancement of the theory and practice of electrochemistry, electrothermics, electronics, and allied subjects. The Society was founded in Philadelphia in 1902 and incorporated in 1930. There are currently over 7,000 scientists and engineers from more than 70 countries who hold individual membership; the Society is also supported by more than 100 corporations through Corporate Memberships. The technical activities of the Society are carried on by Divisions. Sections of the Society have been organized in a number of cities and regions. Major international meetings of the Society are held in the spring and fall of each year. At these meetings, the Divisions and Groups hold general sessions and sponsor symposia on specialized subjects. The Society has an active publications program that includes the following. Journal of The Electrochemical Society -JES is the peer-reviewed leader in the field of electrochemical and solid-state science and technology. Articles are posted online as soon as they become available for publication. This archival journal is also available in a paper edition, published monthly following electronic publication. Letter -ESL is the first and only rapid-publication electronic journal covering the same technical areas as JES. Articles are posted online as soon as they become available for publication. This peer-reviewed, archival journal is also available in a paper edition, published monthly following electronic publication. It is a joint publication of ECS and the IEEE Electron Devices Society. Interface -Interface is ECS's quarterly news magazine. It provides a forum for the lively exchange of ideas and news among members of ECS and the international scientific community at large. Published online (with free access to all) and in paper, issues highlight special features on the state of electrochemical and solid-state science and technology. The paper edition is automatically sent to all ECS members. Meeting Abstracts (formerly Extended Abstracts) -Abstracts of the technical papers presented at the spring and fall meetings of the Society are published on CD-ROM. -This online database provides access to full-text articles presented at ECS and ECS-sponsored meetings. Content is available through individual articles, or as collections of articles representing entire symposia. Monograph Volumes -The Society sponsors the publication of hardbound monograph volumes, which provide authoritative accounts of specific topics in electrochemistry, solid-state science, and related disciplines.

Fil: Perez, P. Gimena. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Houssay. Instituto de Tecnologias y Ciencias de la Ingenieria "Hilario Fernandez Long". Universidad de Buenos Aires. Facultad de Ingenieria. Instituto de Tecnologias y Ciencias de la Ingenieria ; Argentina

For the past decade, much attention was focused on polysaccharide natural resources for various purposes. Throughout the works, several efforts were reported to prepare new function of chitosan by chemical modifications for renewable energy, such as fuel cell application. This paper focuses on synthesis of the chitosan derivative, namely, O-nitrochitosan which was synthesized at various compositions of sodium hydroxide and reacted with nitric acid fume. Its potential as biopolymer electrolytes was studied. The substitution of nitro group was analyzed by using Attenuated Total Reflectance Fourier Transform Infra-Red (ATR-FTIR) analysis, Nuclear Magnetic Resonance (NMR) and Elemental Analysis (CHNS). The structure was characterized by X-ray Diffraction (XRD) and its thermal properties were examined by using differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). Whereas, the ionic conductivity of the samples was analyzed by electrochemical impedance spectroscopy (EIS). From the IR spectrum results, the nitro group peaks of O-nitrochitosan, positioned at 1646 and 1355 cm -1 , were clearly seen for all pH media. At pH 6, O-nitrochitosan exhibited the highest degree of substitution at 0.74 when analyzed by CHNS analysis and NMR further proved that C-6 of glucosamine ring was shifted to the higher field. However, the thermal stability and glass transition temperatures were decreased with acidic condition. The highest ionic conductivity of O-nitrochitosan was obtained at ~10 -6 cm -1 . Overall, the electrochemical property of new O-nitrochitosan showed a good improvement as compared to chitosan and other chitosan derivatives. Hence, O-nitrochitosan is a promising biopolymer electrolyte and has the potential to be applied in electrochemical devices.

This article leverages extensive datasets from NASA, ESA, and peer-reviewed studies (2007-2025) to argue that Venus fails multiple quantitative criteria defining a dynamically stable planet. Its rotational kinetic energy is below the fragmentation threshold, with a retrograde sidereal period of-243.0226 ± 0.0001 days and specific angular momentum far below critical values. Atmospheric entropy export is negligible at ∼2.1 W m-2 K-1 , indicating thermodynamic stagnation, and its magnetic Reynolds number (Rm) is <1, signifying no dynamo activity and vulnerability to solar wind erosion. The vitality parameter E (energy-to-binding-energy ratio) places Venus at 0.14 ± 0.02, aligning it with disrupted objects like (16) Psyche (E ≈ 0.12) rather than active planets (e.g., Earth at 0.41). Critiquing the IAU's 2006 geometric definition, we propose a physicochemical framework: E ≥ 0.15, entropy export Σ ≥ 10 W m-2 K-1 , and Rm ≥ 10. Venus fails all criteria, warranting reclassification as a "dead planetarymass fragment" (DPMF), with implications for exoplanet catalogs where 8-15% of sub-Neptunes may be DPMFs. 1,4,10,20,30,79

NMR microimaging may be used to observe the effect of molecular diffusion in the vicinity of a thin wire subjected to current pulses. By this means the pulsed gradient spin echo technique can utilize very large pulsed magnetic field gradients, on the order of 100 Tm '. The quadratic dependence of gradient amplitude on distance from the wire leads to large dynamic range while the distribution of local gradient vectors makes it possible to image anisotropic diffusion. We demonstrate these properties in measurements on polymer solutions and liquid crystals.

A series of different chain length of fatty acids, fatty acid-ascorbic acid and fatty acid-amino acid conjugates such as (C 17 H 35 -CO 2 H/ C 15 H 31 -CO 2 H/ C 13 H 27 -CO 2 H and C 15 H 31 -As-OH/C 15 H 31 -Trp-OH respectively) were utilized to prepare 1-alkyl-3-methylimidazolium based ionic liquids. The synthesis involved first the preparation of 1-alkyl-3-methylimidazolium bromide ionic liquid from 1-methylimmidazole and 1-bromoalkane using microwave heating. 1-Alkyl-3-methylimidazolium bromides ILs were then converted into their corresponding hydroxide through ion exchange. The final ionic liquids were prepared by the neutralization 1alkyl-3-methylimidazolium hydroxide with fatty acids and fatty acid conjugates. In a typical synthesis of 1-butyl-3methylimidazolium bromide [BMIM][Br], an homogeneous mixture of 1-methylimidazole (10 mm) and 1-bromobutane (10 mm) was heated intermittently in an unmodified household MW oven (Haier HR 2485EG 230V-50 Hz) at 340 W (40 s irradiation with 10 s mixing) until a clear single phase was obtained. The bulk temperature recorded was in the range of 70 °C. The resulting yellowish viscous compound was then cooled, repeatedly washed with diethyl ether (3 x 10 mL) to remove unreacted components. Purified waxy product was dried under vacuum at 80 °C and characterized by 300 MHz 1 H NMR spectroscopy (CDCl 3 ) and ESI mass spectroscopy. Similarly, we have also prepared 1-decyl-3-methylimidazolium bromide [DMIM][Br].

The phenomenon of relaxation in dielectric materials is described as one of the powerful tools to determine the behavior and properties of ion transport. The kinetics of ionic species and dipole in solid-state electrolyte are dependent on frequency, temperature, and dielectric relaxation. Li 1+x Ti 2Àx Al x (PO 4 ) 3 conducting solid state electrolyte with x = 0.3 was synthesized via conventional solid state technique using the raw materials Li 2 CO 3 , TiO 2 , Al 2 O 3 , and NH 4 H 2 PO 4 as starting materials. TGA/DTG and X-ray diffraction measurements were carried out to study the thermal behavior and phases of the composition. It was observed from the TGA/DTA curves that there is no mass loss above 500 °C. The XRD peaks were observed to start appearing at 500 °C which corresponds to small peaks in TGA. It was also pointed out that at increasing sintering temperatures from 700 °C to 1000 °C the number of phases drastically decreased which is attributed to the complete chemical reaction. Temperature and frequency dependence of dielectric relaxation and electric modulus of the compounds were investigated at temperatures 30-230 °C and at frequencies of 40 kHz-1 MHz. The findings showed that the dielectric relaxation peaks shift to higher temperature as frequency increases and the change in ac conductivity with frequency is in agreement with Jonscher's power law.

Solid polymer electrolytes, in the form of membranes, offering high chemical and mechanical stability, while maintaining good ionic conductivity, are envisaged as a possible solution to improve performances and safety in different lithium cell configurations. In this work, we designed and prepared systems formed using innovative nanocomposite polymer membranes, based on high molecular weight poly(ethylene oxide) (PEO) and silica nanopowders, produced by the electrospinning technique. These membranes were subsequently gelled with solutions based on aprotic ionic liquid, carbonate solvents, and lithium salt. The addition of polysulfide species to the electrolyte solution was also considered, in view of potential applications in lithium-sulfur cells. The morphology of the electrospun pristine membranes was evaluated using scanning electron microscopy. Stability and thermal properties of pristine and gelled systems were investigated uisng differential scanning calorimetry and thermal gr...

About 25 years ago, Bogdanovic and Schwickardi (B. Bogdanovic, M. Schwickardi: J. Alloys Compd. 1–9, 253 (1997) discovered the catalyzed release of hydrogen from NaAlH4. This discovery stimulated a vast research effort on light hydrides as hydrogen storage materials, in particular boron hydrogen compounds. Mg(BH4)2, with a hydrogen content of 14.9 wt %, has been extensively studied, and recent results shed new light on intermediate species formed during dehydrogenation. The chemistry of B3H8−, which is an important intermediate between BH4− and B12H122−, is presented in detail. The discovery of high ionic conductivity in the high-temperature phases of LiBH4 and Na2B12H12 opened a new research direction. The high chemical and electrochemical stability of closo-hydroborates has stimulated new research for their applications in batteries. Very recently, an all-solid-state 4 V Na battery prototype using a Na4(CB11H12)2(B12H12) solid electrolyte has been demonstrated. In this review, we ...

Dual-conducting polymer films were synthesized by dispersing graphene in an aqueous solution of poly(vinyl alcohol) and 1-propyl-3-methylimidazolium iodide ([C 3 mim]I) ionic liquid and thermally converting the poly(vinyl alcohol) to polyene in the presence of hydroiodic acid catalyst. The electrical and mechanical properties of the resulting free-standing films of the nanocomposite, containing different concentrations of graphene, were analyzed using electrochemical impedance spectroscopy (EIS) and dynamic mechanical analysis (DMA), respectively. Nyquist plots (imaginary vs real components of the frequency-dependent impedance) showed two characteristic arcs representing the composite's electronic and ionic conduction pathways. The conductivity values corresponding to both charge transport mechanisms increased with temperature and the graphene concentration. The enhancement in electronic conductivity is expected because of graphene's high electron mobility. Interestingly, ionic conductivity also showed a significant increase with graphene concentration, approximately triple the extent of the rise in the electronic conductivity, even though the loss and storage moduli of the films increased. (Generally, a higher modulus results in lower ionic conductivities in ionic gels.) Molecular dynamics simulations of the three-component system provided some insights into this unusual behavior. Mean square displacement data showed that the diffusion of the iodide anions was relatively isotropic. The iodide diffusion coefficient was higher in a blend with 5 vol % graphene than in blends with 3 vol % graphene or no graphene. The improvement is attributed to the interfacial effects of the graphene on the free volume of the blend. Furthermore, an exclusion of the iodide ions from the vicinity of graphene was observed in the radial distribution function analysis. The increase in the effective concentration of iodide due to this exclusion and the increase in its diffusion coefficient because of the excess free volume are the primary reasons for the observed enhancement in ionic conductivity by adding graphene.

Langevin-type finite-temperature simulations show that soliton mobility in hydrogen-bonded chains is a nonmonotonic function of temperature. In the temperature range of 170-240 K, soliton mobility ini- tially increases, reaches a maximum at approximately 190 K, subsequently decreases to a minimum at approximately 210 K, and then increases again. This behavior is in qualitative agreement with experi- mental data for ice crystals in the same temperature range.

We extend the microscopic Poisson-Nernst-Planck theory of the effects of mobile charge carriers, completely blocked at the electrodes, on the properties of dielectric materials by incorporating a finite speed of response propagation. The usual microscopic theory is based on the assumption that the diffusion current is given by Fick's law, relating the current density with the gradient of concentration at the same time. On the contrary we assume that the flux of diffusing particles is delayed with respect to the concentration gradient, as suggested by extended thermodynamics formulations. We show that, in the hyperbolic diffusion regime approximation, new trends for the real and imaginary parts of the small-signal electrical impedance of a dielectric containing ions versus the frequency of the applied voltage are expected when the delay time is comparable with the Debye relaxation time. In particular, at sufficiently high frequencies the real part of the conductivity, normally independent of frequency, decreases toward zero because of the finite, rather than the infinite propagation speed present in the hyperbolic diffusion regime model.

Yttrium substituted BaZrO 3 , with nominal composition BaZr0.9Y0.1O3, a ceramic proton conductor, was subject to impedance spectroscopy for temperatures 300 K < T < 715 K at mechanical pressures 1 GPa < p < 2 GPa. The activation energies E a of bulk and grain boundary conductivity from two perovskites synthesized by solid-state reaction and sol-gel method were determined under high pressures. At high temperature, the bulk activation energy increases with pressure by 5% for sol-gel derived sample and by 40% for solid-state derived sample. For the sample prepared by solid-state reaction, there is a large gap of 0.17 eV between the activation energy at 1.0 GPa and > 1.2 GPa. The grain boundary activation energy is around a factor two times as that of the bulk, and it reaches a maximum at 1.25 -1.5 GPa, and then decrease as the pressure increases, indicating higher proton mobility in the grain boundaries at higher pressure. Since this effect is not reversible, it is suggested that the grain boundary resistance decreases as a result of pressure induced sintering. The steady increase of the bulk resistivtiy upon pressurising suggests that the proton mobility depends on the space available in the lattice. In return, an expanded lattice with a/a0 > 1 should thus have a lower activaqtion energy, suggesting that thin films expansive tensile strain could have a larger proton conductivity with desirable properties for applications.

Impedance spectroscopy on the hydrated proton conductor BaZr0.9Y0.1O3 at high temperatures shows that the bulk proton conductivity activation energy Eb scales with the strain parameter ε, as achieved by hydrostatic pressures up to 2 GPa, suggesting that large lattices favor proton diffusivity. At high temperature, Eb increases upon pressure by 40%. The grain boundary activation energy Eg is around twice as Eb, indicating higher proton mobility in grain boundaries as a result of pressure induced sintering. An expanded lattice with strain parameter ε&gt;1 should have lower Eb, suggesting that thin films expansive tensile strain could have larger proton conductivity.

In this work, we suggest an explanation of the electrical conductivity behavior of tellurite glassy systems modified with barium when transition metal oxides (V 2 O 5 -MoO 3 ) present in the glassy matrix are replaced progressively by barium oxide. These glasses of formula x BaO (1x) (0.5V 2 O 5 • 0.5MoO 3 ) 2 TeO 2 are obtained by the standard quenching technique and analyzed by means of impedance spectroscopy. We also report some structural results that explain the effect of the bivalent cation (Ba +2 ) on the electrical response in comparison to the effect of univalent cations on this kind of glassy matrix. The results confirm the existence of a transition from a typical hopping of small polarons response (when the content of BaO is low) to a weak ionic conductive response (when more than 50% of the transition metal oxides content has been replaced by BaO). The independent migration path is suggested by the observed electrical conductivity behavior. In this system, vanadium gives the active centers responsible for the polaron hopping mechanism while barium cations seem to be responsible for the ionic transport regimen.

Recently Braga et al. presented a cell concept with an extraordinary performance, which was much noticed in the community. The discussed cell consisted of a lithium anode and a sulfurcarbon composite cathode, which were separated by a glassy solid electrolyte (SE). The cell showed low cell resistance, high cycle stability and an unusual overcapacity. This overcapacity was a gladly argued subject in the past and was not reproduced so far. Steingart and Viswanathan commented, that this effect simply violates the first law of thermodynamics. According to that, the electrochemical processes described by Braga et al. are no explanation for gaining energy. Furthermore, the used SEs, such as Li2.99Ba0.005OCl (LOC:Ba), feature very high ionic conductivity of approximately 25 mS/cm and activation energies of around 0.06 eV. Herein we present an overview on the reported compounds, which crystallize in the antiperovskite structure, and their Goldschmidt tolerance factor. We reveal that LOC:Ba ...

Cubic garnets Li(7−3x)AlxLa3Zr2O12 (LLAZO) exhibit high conductivity and are envisioned as electrolyte material for all-solid-state batteries. To better understand the role of Al 3+ , we investigated different Al-doped LLAZO prepared by conventional solid-state reaction. Cubic phase was formed at 900°C, confirmed by X-ray diffraction. Based on 6 Li, 7 Li and 27 Al MAS NMR spectroscopies, we identified for different Al doping levels the Li and Al site occupancies and investigated their mobility by 7Li static NMR with variable temperature. Ionic conductivity measurements on pellets were also performed using electrochemical impedance spectroscopy. Li and Al site occupancies were found dependent on Al doping levels and strongly impact ionic mobility. From our measurements, garnet with x=0.35 exhibits higher ionic conductivity than with x=0.24. Al ions were mainly found at octahedral sites (96h) for x=0.35 whereas they were mainly on tetrahedral sites (24d) for x=0.24. More vacancies wer...

Because of the layered structure of vanadium pentoxide films (V 2 O 5 ), approved by XRD measurement, sensitized from different hydrated V 2 O 5 .nH 2 O sols, demonstrated anisotropic conductivities in current voltage (I-V) measurement. Conductivity values, originated from electronic and ionic conductions, differed provided that measurements were performed in a direction parallel to the ribbons rather than perpendicular to them. The overall electrical conductivity of V 2 O 5 nH 2 O sols mainly depended on the hydration state n and the amount of reduced V 4+ ions in which n was determined around 4-6 [1] from the basal distance (17.6 Å) through XRD measurement while V 4+ ions were determined through FTIR analysis. Electronic conduction prevailed in dehydrated V 2 O 5 0.5H 2 O sols whereas non-stoichiometric vanadium pentoxide was a mixed-valence compound and its electronic properties arised from electron hopping between V 4+ and V 5+ ions so-called "small polaron model". Indeed, reduction/oxidation peaks in lithium (Li + ) intercalation by cyclic voltammograms (CV) indicated the V 4+ and V 5+ ions in V 2 O 5 sols. Temperature dependent I-V analysis showed Arheniuss type activation energy, E A , and located in between 0.3-0.5 eV; proposing ionic conduction rather than electronic conduction, specifically proton diffusion in V 2 O 5 film. Indeed, hydration state greater than 0.5 predicted ionic conduction .

Polymer blending is an effective strategy for tailoring material properties by combining complementary polymers
to achieve enhanced structural and functional performance. In this study, poly (ethylene oxide) (PEO) and poly
(vinylidene fluoride) (PVDF) blends were prepared at weight ratios of 90/10, 80/20, 75/25, and 50/50 using the
solution casting method, with N, N-dimethylformamide (DMF) as the solvent. Fourier Transform Infrared (FTIR)
spectroscopy was employed to investigate composition dependent molecular interactions through the analysis of C–
O–C stretching in PEO and C–F stretching in PVDF, while X-ray Diffraction (XRD) was used to assess crystalline
phase structure and degree of crystallinity. The FTIR spectra revealed composition induced peak shifts and intensity
variations, indicating intermolecular interactions and partial miscibility. XRD analysis demonstrated that PEO-rich
blends exhibited higher crystallinity, with characteristic peaks at 2θ ≈ 19.82° and 23.86°, while increased PVDF
content reduced PEO crystallinity and enhanced PVD associated peaks. Results confirm that blend composition
significantly influences molecular interactions, crystalline structure, and phase stability, underscoring the
importance of compositional tuning for optimizing PEO/PVDF based solid polymer electrolytes.

The structural, microstructural, compositional, vibrational, and electrical properties of the rubidium zinc orthophosphate RbZnPO 4 compound have been comprehensively investigated. X-Ray powder diffraction (XRPD) confirmed the crystallization of RbZnPO 4 in a monoclinic system (space group P2 1), adopting a stuffed tridymite-type structure. Elemental analysis via energy-dispersive X-ray spectroscopy (EDS) confirmed the expected stoichiometry and homogeneous elemental distribution, while scanning electron microscopy (SEM) revealed a dense microstructure with submicron grain sizes (B0.4205 mm). Raman spectroscopy identified internal modes and external vibrational modes of the phosphate [PO 4 ] 3À units, confirming the structural integrity of the phosphate framework. Impedance spectroscopy highlighted the semiconducting behavior of the RbZnPO 4 compound, with grain and grain boundary contributions effectively modeled using an equivalent circuit (R 1 //CPE 1) + (R 2 //CPE 2), where R and CPE represent the resistance and the Constant Phase Element, respectively. Temperature-dependent measurements revealed thermally activated conduction, characterized by negative temperature coefficient of resistance (NTCR) behavior. Activation energies for grains, grain boundaries, and total conduction were determined as 0.775, 1.173, and 0.581 eV, respectively. AC conductivity analyses further indicated frequency-dependent transport, consistent with the Overlapping Large Polaron Tunneling (OLPT) mechanism. The conduction mechanism has been thoroughly studied and well understood. These results demonstrate that RbZnPO 4 is a chemically stable, structurally well-defined, and electrically active phosphate, suitable for potential applications in thermally activated ionic or electronic conduction systems, such as sensors.

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Electrolytes are characterized by their ionic conductivity (s i ). It is desirable that overall s i results from the dominant contribution of the ions of interest (e.g. Li 1 in lithium ion batteries or LIB). However, high values of cationic transference number (t 1 ) achieved by solid or gel electrolytes have resulted in low s i leading to inferior cell performances. Here we present an organogel polymer electrolyte characterized by a high liquid-electrolyte-level s i (,10 1 mS cm 21 ) with high t 1 of Li 1 (.0.8) for LIB. A conventional liquid electrolyte in presence of a cyano resin was physically and irreversibly gelated at 606C without any initiators and crosslinkers, showing the behavior of lower critical solution temperature. During gelation, s i of the electrolyte followed a typical Arrhenius-type temperature dependency, even if its viscosity increased dramatically with temperature. Based on the Li 1 -driven ion conduction, LIB using the organogel electrolyte delivered significantly enhanced cyclability and thermal stability.

The Li + diffusion coefficients in Li + -adsorbed graphene systems were determined by combining first-principle calculations based on density functional theory with Kinetic Monte Carlo simulations. The calculated results indicate that the interactions between Li ions have a very important influence on lithium diffusion. Based on energy barriers directly obtained from first-principle calculations for single-Li + and two-Li + adsorbed systems, a new equation predicting energy barriers with more than two Li ions was deduced. Furthermore, it is found that the temperature dependence of Li + diffusion coefficients fits well to the Arrhenius equation, rather than meeting the equation from electrochemical impedance spectroscopy applied to estimate experimental diffusion coefficients. Moreover, the calculated results also reveal that Li + concentration dependence of diffusion coefficients roughly fits to the equation from electrochemical impedance spectroscopy in a low concentration region; however, it seriously deviates from the equation in a high concentration region. So, the equation from electrochemical impedance spectroscopy technique could not be simply used to estimate the Li + diffusion coefficient for all Li + -adsorbed graphene systems with various Li + concentrations. Our work suggests that interactions between Li ions, and among Li ion and host atoms will influence the Li + diffusion, which determines that the Li + intercalation dependence of Li + diffusion coefficient should be changed and complex.

Ionic liquids are attractive and safe electrolytes for diverse electrochemical applications such as advanced rechargeable batteries with high energy densities. Their properties that are beneficial for energy storage and conversion include negligible vapor-pressure, intrinsic conductivity as well as high stability. To explore the suitability of a series of ionic liquids with small ammonium cations for potential battery applications, we investigated their thermal and transport properties. We studied the influence of the symmetrical imide-type anions bis(trifluoromethanesulfonyl)imide ([TFSI] -) and bis(fluorosulfonyl)imide ([FSI] -), side chain length and functionalization, as well as lithium salt content on the properties of the electrolytes. Many of the samples are liquid at ambient temperature, but their solidification temperatures show disparate behavior. The transport properties showed clear trends: the dynamics are accelerated for samples with the [FSI] -anion, shorter side chains, ether functionalization and lower amounts of lithium salts. Detailed insight was obtained from the diffusion coefficients of the different ions in the electrolytes, which revealed the formation of aggregates of lithium cations coordinated by anions. The ionic liquid electrolytes exhibit sufficient stability in NMC/Li half-cells at elevated temperatures with small current rates without the need of additional liquid electrolytes, although Li-plating was observed. Electrolytes containing [TFSI] - anions showed superior stability compared to those with [FSI] -anions in battery tests.

PEO 16 -LiClO 4 -ZnAl 2 O 4 nanocomposite polymer electrolyte (NCPE) films prepared by hot-pressing method have been investigated. In order to compare with the hot-pressed NCPEs, the NCPE films have also been prepared using the conventional solution-casting method. Field emission scanning electron microscopy (FESEM), differential scanning calorimetry (DSC), conductivity ( ) and interface property studies have been carried out on above two kinds of films. The results show that the NCPE film prepared by hot-pressing method has smoother surface, higher interface stability, lower crystallization and melting temperature values than that prepared by solution-casting method. An all-solid-state lithium polymer battery using the hot-pressed NCPE film as electrolyte, lithium metal and LiFePO 4 as anode and cathode respectively, shows high discharge specific capacity, good rate capacity, high coulombic efficiency, and excellent cycling stability as revealed by galvanostatical charge/discharge cycling tests.

In order to obtain highly conductive polymer gel electrolytes for electrochemical devices, Poly (vinylidene fluoride) (PVdF) based gel electrolytes, namely, (100-x)PVdF + xNH 4 SCN electrolyte system has been synthesized by solution cast technique and characterized by XRD, DSC, IR, SEM and electrical measurements. IR study of gel electrolytes shows interaction of PVdF matrix and dopant salt with prominence of α-phase. This result is also well supported by XRD and DSC studies. The electrolytes are electrochemically stable within ± 1.5 V. The optimum bulk electrical conductivity for 90PVdF + 10NH 4 SCN electrolyte has been found to be ~ 2.5 × 10 -2 S•cm -1 . Dielectric relaxation behavior shows low frequency dispersion and α c -related relaxation peak is observed in loss spectra. Polarization behavior of gel electrolyte shows ionic nature of charge transport (T ion. > 0.90). The temperature dependent conductivity shows VTF behavior.

A method for the preparation of electrospun with fibers possessing a ribbon-like cross-sectional shape was developed. These materials could prove beneficial as flow-through electrodes, since ribbons provide a higher surface-to-volume ratio compared to fibers, thereby providing higher reactive surface area at a given porosity. Fabrication of these materials was accomplished by electrospinning a coaxial fiber with a polystyrene core and polyacrylonitrile shell, followed by leaching of the core material leading to the collapse of the shell into a flat ribbon. The surviving shell was then carbonized to make an electrically conductive and electrochemically reactive fibrous structure. Analysis by x-ray computed tomography showed that ribbons of approximately 400 nm × 800 nm were produced, and experimental characterization revealed that they did indeed offer higher volumetric surface area than previously reported electrospun cylindrical fiber electrodes. The electrodes were characterized for various physical and transport properties and compared to commercial Freudenberg H23 carbon paper in terms of performance in a vanadium redox flow battery. The ribbon-based electrode had better performance and higher power density than commercial Freudenberg H23 electrode in the activation region, though suffered early onset of mass transfer limitations.

The electric conductivity and the initial thermoelectric power are determined for the solid solutions (Ag, Na)X (X = Cl, Br) over the whole composition range. Data drawn from both kinds of measurements allow to approximately estimate the contributions of cation vacancies and interstitial Ag* to the transport process. Two composition regions are distinguished: 0≦NNaX≦0.6 and 0.7

Determinations of the initial thermoelectric power were carried out at 1000 K in the whole composition range of the molten systems AgI-Ag2XO4 (X = Mo, W). For the composition XAgI= 0.8 the investigation was extended to the variation of the thermal emf at the “melting point” of the electrochemically noteworthy glass-like phases, obtained through rapid quenching of the melt. The hypothesis that these glass-like materials could keep the melt configuration at room temperature is contradicted by the results on the molten systems; more complex interpretations, based on the behaviour of the thermal emf at the “m.p.” are proposed.

Small-angle neutron scattering (SANS) combined with powder neutron diffraction (PND) were employed to study phase formation upon absorption/desorption of hydrogen gas in Li-and Naintercalated fullerides. The comparative system analysis, addressing changes in the sample phase compositions and morphology of powders, revealed higher degree of complexity in the Na-based samples. Results also showed that disappearance of the crystalline lithium/sodium hydride during desorption was accompanied by an increased surface roughness in both systems, most likely due to formation of a local surface strain. Furthermore, increased specific internal surface of the studied materials upon subsequent deuterium absorption/desorption cycles was demonstrated. This could indicate moderate fracturing of crystallites.

Energy density and safety are the main factors that govern the development of the rechargeable battery technology. Currently, batteries beyond typical Li-ion batteries such as those based on solid-state electrolytes (SSEs) or other active elements (e.g., Na or Mg) are being examined as alternatives. For example, SSEs that would enable stable and reliable operation of all-solid-state Li-, Na-, and Mg-based batteries, with preferably improved capacity, are considered to be one of the most desired inventions. Lightweight complex metal hydrides are a family of solid compounds that were recently discovered to have extraordinary ionic conductivities and, in some cases, electrochemical properties that enabled battery reversibility. Consequently, they have become one of the promising electrolyte materials for future development of electrochemical storage devices. In this work, we present an overview of a wide range of lightweight hydride-based materials that could be used as electrolytes and/or anodes for mono-/divalent batteries and have a pivotal role in the implementation of new technological solutions in the field of electrochemistry.

KBaPO 4recently reported to hydrate in steam at 80°C into a novel low-temperature protonic conductorwas synthesized by a solid state reaction and its electrical properties characterized by impedance spectroscopy. At high temperatures the conductivity of KBaPO 4 was low (order of 10 -6 S/cm at 600°C) and not significantly different in dry and wet atmospheres, suggesting that KBaPO 4 does not take up and conduct protons to any significant extent under these conditions. It was also independent of oxygen partial pressure and increased by acceptor doping (K excess), suggesting that the transport is ionic and by an effectively positive charge carrying defect. Impedance spectroscopy displayed significant grain boundary series resistance, and the bulk and grain boundaries displayed activation energies of approximately 110 and 120 kJ/mol, respectively. At lower temperatures, the conductivity increased, typical of transport in adsorbed water in a porous sample. Exposure of KBaPO 4 to steam at 80°C resulted in decomposition into Ba 3 (PO 4 ) 2 and a liquid phase, presumably a molten hydrate of K 3 PO 4 . We thus suggest that what literature proposes as protonic conduction in steamed KBaPO 4 in fact represents transport of K + , OH -and HPO 4 2ions in the molten hydrate of the decomposition product K 3 PO 4 held inside porous Ba 3 (PO 4 ) 3 .

This work aims to prepare LiZnVO4 nanoparticles and incorporate them into PVDF as a host polymeric material using the casting method for rechargeable Li-battery applications. The effect of LiZnVO4 on the structural and optical properties of the samples was studied using XRD, FT-IR, and UV-is techniques. Moreover, the electrical conductivity of the prepared films was studied. The XRD spectra show the semicrystalline structure of PVDF and the rhombohedral structure of LiZnVO4. Scherer&#39;s equation was used to determine the crystallite size of LiZnVO4 which is nearly 83 nm. The interaction between PVDF and LiZnVO4 was approved by shifting some FT-IR bands. The band gap energies were decreased by increasing LiZnVO4 due to the density in the localized states in the mobility band gap in PVDF. The AC parameters as a function of frequency and temperature were investigated in detail. Both ε&#39; and ε&quot; had their maximum values at low frequencies and decreased as the frequency and temp...