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  • 1. Ahmed, I.
    et al.
    Eriksson, S-G
    Ahlberg, E.
    Knee, C. S.
    Berastegui, P.
    Johansson, L-G
    Rundlöf, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Karlsson, M.
    Matic, A.
    Börjesson, L.
    Engberg, D.
    Synthesis and structural characterization of perovskite type proton conducting BaZr1-xInxO3-delta (0.0 <= x <= 0.75)2006In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 177, no 17-18, p. 1395-1403Article in journal (Refereed)
    Abstract [en]

    Solid state sintering has been used to prepare the cubic perovskite structured compounds BaZr1-xInxO3-delta (0.0 <= x <= 0.75). Analysis of X-ray powder diffraction (XRPD) data reveals that the unit cell parameter, a, increases linearly with an increased Indium concentration. XRPD data was also used to demonstrate the completion of sample hydration, which was reached when the materials showed a set of single-phase Bragg-peaks. Dynamic thermogravimetric analysis (TGA) data showed that approx. 89% of the total number of available oxygen vacancies can be filled in BaZr1-xInxO3-delta for x=0.50, and that the maximum water uptake occurs below 300 degrees C. Rietveld analysis of the room temperature neutron powder diffraction (NPD) data confirmed the average cubic symmetry (space group Pm-3m), and an expansion of the unit cell parameter after the hydration reaction. The strong O-H stretch band, 2500-3500 cm(-1), in the infrared absorbance spectrum clearly manifests the presence of protons in the hydrated material. Proton conductivity of hydrated BaZr1-xInxO3-delta, x=0.75 was investigated during heating and cooling cycles under dry argon atmosphere. The total conductivity during the heating cycle was nearly two orders of magnitude greater than that of cooling cycle at 300 degrees C, whilst these values were similar at higher temperatures i.e. T > 600 degrees C.

  • 2.
    Ainla, Alar
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Brandell, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Nafion (R)-polybenzimidazole (PBI) composite membranes for DMFC applications2007In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 178, no 7-10, p. 581-585Article in journal (Refereed)
    Abstract [en]

    Nafion®–PBI composites were prepared by diffusing synthesized PBI from solution phase into Nafion® membranes, using different concentrations and drying temperatures. In some cases, Nafion® was treated with diethyl amine to screen the –SO3H groups and thereby avoid the strong acid–base interactions between the polymers during diffusion. The presence of PBI in the membranes was characterized with FT–IR spectroscopy. The performance of the membranes was studied by in-plane conductivity and methanol permeability. The performance ratio (the ratio between conductivity and methanol permeability compared to Nafion®) increased by up to 50% for the composite membranes compared to Nafion®.

  • 3. Araujo, Rafael Barros Neves de
    et al.
    Scheicher, Ralph H.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    de Almeida, J. S.
    Ferreira da Silva, A.
    Ahuja, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    First-principles investigation of Li ion diffusion in Li2FeSiO42013In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 247, p. 8-14Article in journal (Refereed)
    Abstract [en]

    We have studied the Li-ion migration and the electrochemical performance of Li2FeSiO4 in the monoclinic crystal structure with P2(1) symmetry and the related delithiated system LiFeSiO4. For this purpose, the framework of the density functional theory within the generalized gradient approximation in conjunction with the climbing image nudged elastic band method was used. Addition of the Hubbard term was also considered in the Kohn-Sham Hamiltonian to better model the d electrons of the metal ions in this material. The calculated activation energies for Li ion migration are found to decrease by around 20% with the Hubbard term inclusion in the chosen diffusion pathways of Li2FeSiO4. Regarding the delithiated structure, the activation energies were found to be sensitive to the Hubbard term addition, however no general behavior such as in the lithiated structure was found. Furthermore, the diffusion coefficients were calculated considering temperatures of 300 K, 500 K, and 700 K.

  • 4.
    Babulanam, SM
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Ionic thermocurrents in sodium fluoride thin film1986In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 20, p. 191-196Article in journal (Refereed)
  • 5.
    Bergfelt, Andreas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Polymer Chemistry.
    Rubatat, Laurent
    CNRS/UNIV Pau & Pays Adour, Institut des Sciences Analytiques et de Physico-Chimie pour l´ Environnement et les Materiaux, Pau, France.
    Brandell, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Bowden, Tim
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Polymer Chemistry.
    Poly(benzyl methacrylate)-Poly[(oligo ethylene glycol) methyl ether methacrylate] Triblock-Copolymers as Solid Electrolyte for Lithium Batteries2018In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 321, p. 55-61Article in journal (Refereed)
    Abstract [en]

    A triblock copolymer of benzyl methacrylate and oligo(ethylene glycol) methyl ether methacrylate was polymerized to form the general structure PBnMA-POEGMA-PBnMA, using atom transfer radical polymerization (ATRP). The block copolymer (BCP) was blended with lithium bis(trifluoro methylsulfonate) (LiTFSI) to form solid polymer electrolytes (SPEs). AC impedance spectroscopy was used to study the ionic conductivity of the SPE series in the temperature interval 30 °C to 90 °C. Small-angle X-ray scattering (SAXS) was used to study the morphology of the electrolytes in the temperature interval 30 °C to 150 °C. By using benzyl methacrylate as a mechanical block it was possible to tune the microphase separation by the addition of LiTFSI, as proven by SAXS. By doing so the ionic conductivity increased to values higher than ones measured on a methyl methacrylate triblock copolymer-based electrolyte in the mixed state, which was investigated in an earlier paper by our group. A Li|SPE|LiFePO4 half-cell was constructed and cycled at 60 °C. The cell produced a discharge capacity of about 100 mAh g−1 of LiFePO4 at C/10, and the half-cell cycled for more than 140 cycles.

  • 6.
    Berggren, Lars
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Niklasson, Gunnar A.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Optical Absorption and Durability of Sputtered Amorphous Tungsten Oxide Films2003In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 165, no 1-4, p. 51-58Article in journal (Refereed)
    Abstract [en]

    Amorphous tungsten oxide films were made by sputtering onto glass substrates that were coated with conductive tin doped indium oxide (ITO). The films were deposited at different O2/Ar gas flow ratios and different substoichiometric compositions was determined by Elastic recoil detection analysis (ERDA). Substoichiometric as-deposited tungsten oxide is transparent above a particular oxygen content and is blue below that content. This indicates that there are at least two kinds of defects in the substoichiometric films. The oxygen vacancies may be coupled to W5+ sites, giving rise to strong absorption, or to (W–W)10+ complexes in the transparent films. Lithium ions were electrochemically intercalated at several charge levels. At each level the transmittance and reflectance were measured in the wavelength range between 0.3 and 2.5 μm. We show that as-deposited blue films and intercalated transparent films display similarly shaped optical absorption bands. Electrochromic devices were made by laminating the tungsten oxide films with sputtered Ni–V oxide deposited on ITO-coated plastic substrates. The durability under electrochemical cycling was best for the case of very substoichiometric WO2.63 films.

  • 7.
    Brandell, Daniel
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Kasemaegi, Heiki
    Tamm, Tarmo
    Aabloo, Alvo
    Molecular dynamics modeling the Li-PolystyreneTFSI/PEO blend2014In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 262, p. 769-773Article in journal (Refereed)
    Abstract [en]

    Classical Molecular Dynamics (MD) simulation studies of the single-ion conductor lithium poly(4-styrenesulfonyl(trifluorosulfonyl)imide) (PSTFSI) are for the first time presented here. The polymer electrolyte system comprises anions which are covalently bonded to a polymer backbone, thus rendering very high positive transport numbers. The studies here include a quantum chemistry based force field generation for this system and MD simulations of PSTFSI and a blend between PSTFSI and poly(ethylene oxide) (PEO). The simulations show that PEO acts as a very good solvent for the Li-ions, and that the transport properties are similar to Li-salt/PEO electrolytes at room temperature conditions, while pure PSTFSI has very little Li mobility at all. Realistic Li diffusion coefficients of similar to 1 x 10(-13) m(2) s(-1) were generated for the PSTFSI/PEO blend.

  • 8.
    Dahbi, Mohammed
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Saadoune, Ismael
    LCME, University Cadi Ayyad, Marrakech, Morocco.
    Gustafsson, Torbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Effect of manganese on the structural and thermal stability of Li 0.3Ni0.7 - yCo0.3−yMn2yO2 electrode materials (y =0 and 0.05)2011In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 203, no 1, p. 37-41Article in journal (Refereed)
    Abstract [en]

    Thermal and structural stabilities of Li(0.3)Ni(0.7)Co(0.3)O(2) and Li(0.3)Ni(0.65)Co(0.25)Mn(0.10)O(2) chemically delithiated cathode materials were studied by X-ray diffraction, thermogravimetric analysis and differential scanning calorimetry. The structure of the Li(0.3)Ni(0.7)Co(0.3)O(2) layered material (S.C. R-3 m) transforms first to the spinel-type structure (S.C. Fd3m) and then to the completely disordered Ni0-type structure (S.C. Fm3m). These structural transitions were accompanied by 10.2% oxygen loss and leads to an exothermic reaction, activated by the electrolyte, more energetic than that of Li(0.3)Ni(0.65)Mn(0.10)O(2) manganese substituted electrode. Furthermore, no structural changes were observed during the thermal treatment of Li(0.3)Ni(0.65)Co(0.25)Mn(0.10)O(2) and relatively lower oxygen loss was recorded. The obtained results prove the positive effect of manganese substitution on the electrochemical features of Li(0.3)Ni(0.7)Co(0.3)O(2).

  • 9.
    Eriksson, Rickard
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Maher, Kenza
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Saadoune, Ismael
    LCME, University Cadi Ayyad, Marrakech, Morocco.
    Mansori, Mohammed
    LCME, University Cadi Ayyad, Marrakech, Morocco.
    Gustafsson, Torbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Electrochemical lithium ion intercalation in Li 0.5Ni 0.25TiOPO 4 examined by in situ X-ray diffraction2012In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 225, no SI, p. 547-550Article in journal (Refereed)
    Abstract [en]

    The complex structural transformations of Li 0.5Ni 0.25TiOPO 4 during electrochemical lithiation have been examined by in situ X-ray diffraction. During the first lithiation two structural changes take place: first a transition to a second monoclinic phase (a = 9.085(4), b = 8.414(5), c = 6.886(5), β = 99.85(4)) and secondly a transition to a third phase with limited long-range order. The third phase is held together by a network of corner sharing Ti-O octahedra and phosphate ions with disordered Ni-Li channels. During delithiation the third phase is partially transformed back to a slightly disordered original phase, Li 0.5Ni 0.25TiOPO 4 without formation of the second intermediate phase. These phase transitions correspond well to the different voltage plateaus that this material shows during electrochemical cycling.

  • 10.
    Gotte, Anders
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Spångberg, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Hermansson, Kersti
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Baudin, Michael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Molecular dynamics study of oxygen self-diffusion in reduced CeO22007In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 178, no 25-26, p. 1421-1427Article in journal (Refereed)
    Abstract [en]

    The oxygen self-diffusion in partially reduced CeO2 has been investigated by large-scale Molecular Dynamics simulations, in the temperature range between 800 and 2200 K. Simulation boxes with ~ 4100 and ~ 33,000 ions were investigated for randomly distributed oxygen vacancies and Ce3+ ions. Our calculated self-diffusion coefficients vary between 10−8 and 10−6 cm2/s in the temperature range studied. The activation energy and D0 values are also reported. The oxygen diffusion mechanism has also been analyzed: only a 100 vacancy mechanism is observed.

  • 11.
    HERMANSSON, KERSTI
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    OJAMAE, LARS
    ON THE ROLE OF ELECTRIC-FIELDS FOR PROTON-TRANSFER IN WATER1995In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 77, p. 34-42Article in journal (Refereed)
    Abstract [en]

    The influence of uniform and non-uniform electric fields on one-dimensional proton transfer curves for (H2O)(2), H5O2+ and H3O2- has been examined using quantum-mechanical ab initio calculations. Both liquid-state and solid-state environments are discussed. For the charged complexes the transfer barrier is removed or greatly reduced by a field as small as 0.005 a.u. (2.5 X 10(7) V/cm). Local field fluctuations of this size are easily produced in condensed aqueous systems at room temperature. For the asymmetric single-well potential of an (H2O)(2) complex, a field ten times larger is needed to move the minimum from one side to the other across the O ... O bond. Such local fields can be achieved in ionic aqueous systems. The energy barrier for proton transfer in ice Ih has been computed using a periodic Hartree-Fock approach; the barrier for a fully concerted proton transfer is similar to 60 kJ/mol.

  • 12.
    Kaewmaraya, Thanayut
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Ramzan, Muhammad
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Osorio-Guillen, J. M.
    Ahuja, R.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Electronic structure and ionic diffusion of green battery cathode material: Mg2Mo6S82014In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 261, p. 17-20Article in journal (Refereed)
    Abstract [en]

    We report ab-initio density functional theory calculations of crystal and electronic structure of Mg2Mo6S8, a candidate material to be used in rechargeable magnesium batteries, by employing hybrid exchange-correlation functionals. We find that Mg2Mo6S8 crystalizes in a triclinic geometry and it is a semiconductor with an indirect band gap. Ab-initio molecular dynamics shows that Mg ions present progressive diffusion starting at 200 K with a preferable path through the channel between Mo6S8 blocks along the [010] direction. The intercalation voltage of the system is also determined and the results show that the voltage evaluated by PBE and hybrid functionals likely implies the lower and the upper limit of the experimental value. Lastly, we confirm the dynamical stability of the crystal structure by the calculated phonon dispersion relation. 

  • 13.
    Kam, Kinson C.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Gustafsson, Torbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Thomas, John O.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Synthesis and electrochemical properties of nanostructured Li(2)FeSiO(4)/C cathode material for Li-ion batteries2011In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 192, no 1, p. 356-359Article in journal (Refereed)
    Abstract [en]

    Nanostructured Li(2)FeSiO(4)/C was synthesized by high-energy ball-milling and the amorphous citrate-assisted techniques. Similar redox behaviour is observed for samples prepared by the amorphous citrate-assisted route followed by a 4 h heat treatment: 0.3 V polarization and more sloping behaviour was observed when cycling between 2.0 V and 3.7 V at 60 degrees C; lower capacity fade is also observed compared to Li(2)FeSiO(4)/C prepared by the solid-state reaction technique. A discharge capacity of 102 mA h g(-1) is obtained for samples prepared by the high-energy ball-milling method, while capacities decrease from 95 to 77 mA h g(-1) using the amorphous citrate method for heat-treatment times increasing successively from 4 h to 18 h.

  • 14.
    Karo, Jaanus
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Brandell, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    A Molecular Dynamics study of the influence of side-chain length and spacing on lithium mobility in non-crystalline LiPF6·PEOx; x = 10 and 302009In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 180, no 23-25, p. 1272-1284Article in journal (Refereed)
    Abstract [en]

    Molecular Dynamics (MD) simulation techniques have been used to investigate systematically how the length and spacing of poly(ethylene oxide) (PEO) side-chains along a PEO backbone influence ion mobility for two different salt concentrations. This is of fundamental relevance to the design of new polymer electrolytes for battery applications. The salt used has been LiPF6 in concentrations corresponding to Li:EO ratios of 1:30 and 1:10. The MD box contained PEO backbones of 89-343 EO units to which 3, 6, 7, 8, 9 and 15 EO unit side-chains were added. The selected spacings along the backbone between the PEO side-chains attachment points were 5, 10, 15, 20 and 50 EO units. The backbone and all side-chains were methoxy end-capped, and the simulations were all made at 293 K. Ion mobilities have been estimated from the variation of mean-square-displacement with time, and have been analysed in relation to chain dynamics, cross-linking and ion pairing. Comparisons are also made with the results of simulated PEO systems without side-chains and/or without salt. It is found that, at a higher concentration, many short side-chains give the highest ion mobility, while the mobility is highest for side-chain lengths of 7-9 EO units at the lower concentration.

  • 15.
    Klarbring, Johan
    et al.
    Linkoping Univ, Dept Phys Chem & Biol IFM, SE-58183 Linkoping, Sweden..
    Vekilova, Olga Yu.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory. KTH Royal Inst Technol, Dept Mat Sci & Engn, Brinellvagen 13, S-10044 Stockholm, Sweden..
    Nilsson, Johan O.
    KTH Royal Inst Technol, Dept Mat Sci & Engn, Brinellvagen 13, S-10044 Stockholm, Sweden..
    Skorodumova, Natalia V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory. KTH Royal Inst Technol, Dept Mat Sci & Engn, Brinellvagen 13, S-10044 Stockholm, Sweden..
    Simak, Sergei I.
    Linkoping Univ, Dept Phys Chem & Biol IFM, SE-58183 Linkoping, Sweden..
    Ionic conductivity in Sm-doped ceria from first-principles non-equilibrium molecular dynamics2016In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 296, p. 47-53Article in journal (Refereed)
    Abstract [en]

    Sm-doped ceria is a prospective electrolyte material for intermediate-temperature solid-oxide fuel cells (IT-SOFC). Equilibrium ab initio molecular dynamics (AIMD) studies of oxygen ion diffusion in this material are currently impractical due to the rareness of diffusive events on the accessible timescale. To overcome this issue we have performed ab initio non-equilibrium molecular dynamics calculations of Sm-doped ceria using the color diffusion algorithm. Applying an external force field we have been able to increase the frequency of diffusive events over the simulation time, while keeping the physical mechanism of diffusion intact. We have investigated the temperature dependence of the maximum strength of the applied external field that could be used while maintaining the response of the system in a linear regime. This allows one to obtain the diffusivity at zero field. The bulk ionic conductivity has been calculated and found to match the experimental data well. We have also compared the description of the diffusion process by our method to previous findings and show that the migration mechanism and site preference of oxygen vacancies with respect to the Sm dopants is well reproduced.

  • 16.
    Lasri, Karima
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Saadoune, Ismael
    LCME, University Cadi Ayyad, Marrakech, Morocco.
    Bentaleb, Yassine
    Mikhailova, Daria
    Ehrenberg, Helmut
    Häggström, Lennart
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Origin of the irreversible capacity of the Fe0.5TiOPO4 anode material2012In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 224, p. 15-20Article in journal (Refereed)
    Abstract [en]

    Fe0.5TiOPO4 oxyphosphate was prepared directly by solid state reaction. It crystallizes in the monoclinic system with P2(1)/c space group and the use of Fe0.5TiOPO4 as an active material in lithium-ion batteries shows two potential plateaus and an irreversible discharge capacity of similar to 200 rnAh/g. To understand the origin of this irreversibility, a series of LixFe0.5TiOPO4 (x = 0.06, 0.21 0.76, 1.14) were chemically prepared and analyzed by X-ray diffraction. A structure amorphization of the LixFe0.5TiOPO4 phosphates takes place during the lithiation process. Magnetization and Mossbauer spectroscopy studies of the LixFe0.5TiOPO4 samples clearly show the formation of iron metal which induces a deterioration of the crystal structure of the studied electrode materials. The lithiation process leads thus to a conversion reaction which explains the irreversibility of the electrochemical process during the first discharge. (C) 2012 Elsevier B.V. All rights reserved.

  • 17.
    Liivat, Anti
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Structural changes on cycling Li 2FeSiO 4 polymorphs from DFT calculations2012In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 228, p. 19-24Article in journal (Refereed)
    Abstract [en]

    Cation mixing has been demonstrated experimentally in the Li-ion battery cathode material Li 2FeSiO 4. This feature is investigated here using DFT calculations. It is shown that full reversal of Li/Fe site occupations is energetically favoured on delithiation for all three electrochemically active Li 2FeSiO 4 polymorphs. The common layered topology in the arrangement of SiO 4 and FeO 4 tetrahedra in all three polymorphs transforms into a 3D-framwork. Calculations show here that such a change in structure leads to a lowering of electrochemical insertion potential from ~ 3.1 to ~ 2.8 V, in good agreement with experimental data. Calculations also predict the correct anisotropy in the cell expansion on delithiation on Li/Fe site reversals. Partial mixing of Li and Fe site occupations is energetically less favourable, which supports a two-phase transformation mechanism.

  • 18.
    Liivat, Anti
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Thomas, John O.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Li-ion migration in Li(2)FeSiO(4)-related cathode materials: A DFT study2011In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 192, no 1, p. 58-64Article in journal (Refereed)
    Abstract [en]

    The orthosilicate family of materials Li(2)MSiO(4) for M = Fe, Mn and Co are coming to be seen as potentially cheap cathode materials for large-scale Li-ion batteries, not least through the possibility for significant capacity gains if more than one Li-ion can be removed per formula unit. To gain insights into possible Li-ion migration pathways and diffusion barriers for Li-ions, model systems for Li(x)FeSiO(4)(x approximate to 1.2) are here studied using the Density Functional Theory (DFT) approach. Li-ion and ion-vacancy migration barriers are calculated for a number of model systems. The results help explain why the Li/Fe site-mixing observed during electrochemical cycling of Li(2)FeSiO(4) does not lead to any noticeable loss in cell performance, despite the increased tortuosity introduced into the Li-migration pathways by this ion-mixing process.

  • 19.
    Nytén, Anton
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Thomas, John
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    A neutron powder diffraction study of LiCoxFe1−xPO4 for x = 0, 0.25, 0.40, 0.60 and 0.752006In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 177, no 15-16, p. 1327-1330Article in journal (Refereed)
    Abstract [en]

    X-ray and neutron powder diffraction studies have been made of the single-phase systems LiCoxFe1−xPO4 (x = 0, 0.25, 0.40, 0.60 and 0.75) to establish how Co2+ substitutes into the LiFePO4 olivine structure. Rietveld refinement shows that all four substituted materials have the same olivine structure (space group: Pnma) with lithium occupying octahedral (4a) sites, and Co2+ replacing Fe2+ at the octahedral (4c) sites. The a and b cell parameters decrease while the c parameter increases on the addition of Co2+. There are certain indications of structural instability for high Co-content compositions.

  • 20.
    Qian, Zhao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Jiang, Xue
    De Sarkar, Abir
    Maark, Tuhina Adit
    Deshpande, Mrinalini D.
    Bououdina, Mohamed
    Johansson, Boerje
    Ahuja, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Screening study of light-metal and transition-metal-doped NiTiH hydrides as Li-ion battery anode materials2014In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 258, p. 88-91Article in journal (Refereed)
    Abstract [en]

    Here we have investigated systematically the effects of various light-metals (Mg, Al) and transition-metals (V, Cr, Mn, Fe, Co, Cu, Zn) on the electrochemical properties of NiTiH hydrides as anodes for Li-ion battery applications. Based on the pristine NiTiH, a screening study in terms of the structure volume, average voltage and specific capacity has been performed to choose the most proper metal dopants. The most thermodynamically stable doping sites (Ni or Ti site) of various dopant metals have been determined respectively. It is finally summarized that in this study, the light metal Al or the transition metals Cr, Mn and Fe have the most comprehensive effects and are the most promising metal dopants for the pristine NiTiH hydride. This theoretical study is proposed to help understand the properties of the material and guide the design and development of more efficient metal-hydrides materials for Li-ion battery anode applications.

  • 21.
    Renault, Stevén
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Oltean, Viorica Alina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Ebadi, Mahsa
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Brandell, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Dilithium 2-aminoterephthalate as a negative electrode material for lithium-ion batteries2017In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 307, p. 1-5Article in journal (Refereed)
    Abstract [en]

    This work presents the synthesis and characterization of a novel organic Li-battery anode material: dilithium 2-aminoterephthalate (C8H5Li2NO4). When investigated in Li half-cells, the resulting electrodes show stable capacities around ca. 180 mAh g− 1 and promising rate capabilities, with battery performance at 500 mA g− 1 and good capacity recovery, despite being an asymmetric compound. DFT calculations indicate a preferential lithiation on carboxylates close to the amino group.

  • 22.
    Saadoune, Ismael
    et al.
    LCME, University Cadi Ayyad, Marrakech, Morocco.
    Dahbi, Mohammed
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Wikberg, Magnus
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Gustafsson, Torbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Svedlindh, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Effect of the synthesis temperature on the structure and electrochemical behaviour of the LiNi0.65Co0.25Mn0.1O2 positive electrode material2008In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 178, no 31-32, p. 1668-1675Article in journal (Refereed)
    Abstract [en]

    Three kinds of LiNi0.65Co0.25Mn0.1O2 samples were prepared using a combustion method at different synthetic conditions (C1: 900 °C/1 h; C2: 900 °C/12 h and C3: 1000 °C/12 h). The samples were characterized using X-ray diffraction, scanning electron microscopy and magnetization measurements before their use as positive electrode material in lithium-ion batteries. Sample C1 presents the most ordered structure with less than 3% of nickel ions in the lithium plane. Increasing synthesis temperature and/or time lead to an increase of the Li/Ni disorder. The amount of extra-nickel ions in the lithium plane strongly affects the magnetic behaviour and the electrochemical performances of the prepared material. LiNi0.65Co0.25Mn0.1O2 prepared at 900 °C for 1 h presents the best cycling properties.

  • 23.
    Sun, Bing
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Mindemark, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Brandell, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Polycarbonate-based solid polymer electrolytes for Li-ion batteries2014In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 262, p. 738-742Article in journal (Refereed)
    Abstract [en]

    This paper reports the synthesis and application of high-molecular-weight poly(trimethylene carbonate) (PTMC) as a new host material for solid polymer electrolyte-based Li-ion batteries. PTMC was synthesized through bulk ring-opening polymerization of the cyclic monomer to yield a high-molecular-weight polymer to serve as a base material for the electrolytes. The thermal properties and ionic conductivity of polymer electrolytes with different salt ratios were measured by TGA/DSC and electrochemical impedance spectroscopy, respectively. The most conductive systems were found at [Li+]:[carbonate] ratios of 1:13 and 1:8, which showed electrochemical stability up to 5.0 V vs. Li/Li+ and an ionic conductivity on the order of 10− 7 Scm(-1) at 60 °C. LiFePO4 half-cells using the electrolytes demonstrated a plateau in the specific discharge capacity around 153 mAhg(-1) after long-term cycling. The functionality of the electrolytes for three-dimensional microbatteries was also confirmed.

  • 24.
    Tan, Semra
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Perre, Emilie
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Gustafsson, Torbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Brandell, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    A solid state 3-D microbattery based on Cu 2Sb nanopillar anodes2012In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 225, p. 510-512Article in journal (Refereed)
    Abstract [en]

    A 3D-microbattery consisting of nanostructured Cu 2Sb, a solid state electrolyte and a metallic lithium foil has been investigated electrochemically. Thin-film Cu 2Sb electrodes have been prepared by heat treatment of electrodeposited Sb on both 2D and 3D-nanopillar Cu substrates. A solid electrolyte based on UV cross-linked blends of poly(propylene glycol) diacrylate and polyetheramine (glyceryl poly(oxypropylene)) was thereafter deposited onto the electrode material, and then cycled against Li. It is demonstrated that the discharge capacity per footprint area for the 3D-nanopillar samples increased more than 10 times as compared to that of the 2D system.

  • 25.
    Tan, Semra
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Walus, Sylwia
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Gustafsson, Torbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Brandell, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    3-D microbattery electrolyte by self-assembly of oligomers2011In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 198, no 1, p. 26-31Article in journal (Refereed)
    Abstract [en]

    This paper reports the preparation and characterization of novel thin film electrolytes by UV cross-linking of poly(propylene glycol) diacrylate in the presence of polyetheramine (glyceryl poly(oxypropylene)triamine) and LiTESI. The oligomeric surfactant polyetheramine facilitates self-assembly of the electrolyte, enabling it to be applied conformally onto a complex substrate which is necessary for 3D-microbatteries, while the acrylate network supplies mechanical stability. Conformal coatings onto LiFePO(4) electrodes and Cu nanopillars were confirmed by SEM. Ionic conductivities of 3.5 x 10(-6) and 5.8 x 10(-5) S/cm were measured at room temperature and 60 degrees C, respectively, at Li:O = 1:20 and PEA:PPGDA = 2:1 ratios. The electrochemical stability window test showed that the electrolyte is stable above 5.0 V vs. Li/Li(+). Thermal analyses by TGA and DSC demonstrated that the polymer electrolyte is amorphous and thermally stable up to 300 degrees C.

  • 26.
    Wieczorek, P.
    et al.
    Warsaw Univ Technol, Fac Chem, Polymer Ion Res Grp, Noakowskiego 3, PL-00664 Warsaw, Poland..
    Bitner-Michalska, A.
    Warsaw Univ Technol, Fac Chem, Polymer Ion Res Grp, Noakowskiego 3, PL-00664 Warsaw, Poland..
    Niedzicki, L.
    Warsaw Univ Technol, Fac Chem, Polymer Ion Res Grp, Noakowskiego 3, PL-00664 Warsaw, Poland..
    Zero, E.
    Warsaw Univ Technol, Fac Chem, Polymer Ion Res Grp, Noakowskiego 3, PL-00664 Warsaw, Poland..
    Zukowska, G. Z.
    Warsaw Univ Technol, Fac Chem, Polymer Ion Res Grp, Noakowskiego 3, PL-00664 Warsaw, Poland..
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Wieczorek, W.
    Warsaw Univ Technol, Fac Chem, Polymer Ion Res Grp, Noakowskiego 3, PL-00664 Warsaw, Poland..
    Marcinek, M.
    Warsaw Univ Technol, Fac Chem, Polymer Ion Res Grp, Noakowskiego 3, PL-00664 Warsaw, Poland..
    Compatibility of microwave plasma chemical vapor deposition manufactured Si/C electrodes with new LiTDI-based electrolytes2016In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 286, p. 90-95Article in journal (Refereed)
    Abstract [en]

    A synthesis of new types of Si/C composite anodes for lithium -ion batteries is reported. Thin layers of graphitic carbon decorated in 3D with Si nanoparticles were produced from liquid organic precursors-1-phenyl-2trimethylsilylacetylene and triethoxy(octyl)silane, using a one-step microwave plasma chemical vapor deposition (MPCVD) method. Thin-film Si/C electrodes were electrochemically tested in lithium half cells and produced a good reversible capacity of up to 900 mAh g-1 (after 100 cycles) and -370 mAh g(-1), depending on the precursor type. The electrode easily endured 100 cycles at 1C rate with only a 10% loss in capacity.

  • 27.
    Zadin, Vahur
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Brandell, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Kasemaegi, Heiki
    Aabloo, Alvo
    Thomas, John O.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Finite element modelling of ion transport in the electrolyte of a 3D-microbattery2011In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 192, no 1, p. 279-283Article in journal (Refereed)
    Abstract [en]

    A mathematical model describing ionic transport in a 3D-microbattery (3D-MB) electrolyte is developed here using finite element methodology. The model is then exploited to study a 3D-MB based on an interdigitated plate ("trench") architecture for a 10 pm-thick electrolyte layer separating 10 mu m-thick graphite anode and LiCoO(2) cathode plates. The effect of varying plate length, end-shape and electronic conductivity is also modelled. It is shown that the 3D-MB architecture gives rise to qualitatively non-uniform current densities, leading to sub-optimal surface utilization. This can, in turn, be optimized by varying electrode geometries and/or material properties.

1 - 27 of 27
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