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  • 151.
    Ebadi, Mahsa
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry. Uppsala university-Department of Chemistry - Ångström Laboratory.
    Modelling the Molecular World of Electrolytes and Interfaces: Delving into Li-Metal Batteries2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Lithium metal batteries (LMBs) are potential candidates for powering portable electronic devices and for electromobility. However, utilizing the reactive Li metal electrode means tackling serious challenges in terms of safety risks. A better understanding of electrolytes and solid electrolyte interphase (SEI) formation are highly important in order to improve these issues.

    In this thesis, density functional theory (DFT) and molecular dynamics (MD) are used to explore novel electrolyte systems and the interfacial chemistry of electrolyte/Li metal surfaces. In the first part, the electronic structure and possible decompositions pathways of organic carbonates at the Li metal surface are investigated, which provide information about initial SEI formation. Computed X-ray photoelectron spectroscopy (XPS) for these interfacial compounds is used as a tool to find likely electrolyte decomposition pathways and are supported by direct comparison with the experimental results. The electronic structure and computed XPS spectra of electrolyte solvents and the LiNO3 additive on Li metal by DFT provide atomistic insights into the interphase layer.

    Solid polymer electrolytes (SPEs) are promising electrolytes to be used with the Li metal electrode. In the second part of the thesis, MD simulations of poly(ethylene oxide) (PEO) doped with LiTFSI salt/Li metal interface demonstrate the impact of the surface on the structure and dynamics of the electrolyte. A new interfacial potential model for MD simulations is also developed for the interactions at the SPE/metal interface, which can better capture this chemical interplay. Moreover, the approach to improve the ionic conductivity of SPEs by adding side-chains to the backbone of polymers is scrutinized through MD simulations of the poly(trimethylene carbonate) (PTMC) system. While providing polymer flexibility, a hindering effects of the side-chains on Li+ ion diffusions through reduced coordination site connectivity is observed.

    In the final part, different polymer hosts interacting with Li metal are explored, and rapid decomposition of polycarbonates and polyester on the surface is seen. The complexes of these polymers with LiTFSI and LiFSI showed significant changes in the computed electrochemical stability window and salt degradations. Lastly, Li2O was obtained by DFT calculations as a thermodynamically stable layer on the surface of the Li metal oxidized by PEO.

    The modelling studies performed in this thesis highlight the applicability of these techniques in order to probe the SEI and electrolyte properties in LMBs at the atomistic level.

    List of papers
    1. Electrolyte decomposition on Li-metal surfaces from first-principles theory
    Open this publication in new window or tab >>Electrolyte decomposition on Li-metal surfaces from first-principles theory
    2016 (English)In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 145, no 20, article id 204701Article in journal (Refereed) Published
    Abstract [en]

    Animportant feature in Li batteries is the formation of a solid electrolyte interphase (SEI) on the surface of the anode. This film can have a profound effect on the stability and the performance of the device. In this work, we have employed density functional theory combined with implicit solvation models to study the inner layer of SEI formation from the reduction of common organic carbonate electrolyte solvents (ethylene carbonate, propylene carbonate, dimethyl carbonate, and diethyl carbonate) on a Li metal anode surface. Their stability and electronic structure on the Li surface have been investigated. It is found that the CO producing route is energetically more favorable for ethylene and propylene carbonate decomposition. For the two linear solvents, dimethyl and diethyl carbonates, no significant differences are observed between the two considered reduction pathways. Bader charge analyses indicate that 2 e(-) reductions take place in the decomposition of all studied solvents. The density of states calculations demonstrate correlations between the degrees of hybridization between the oxygen of adsorbed solvents and the upper Li atoms on the surface with the trend of the solvent adsorption energies.

    National Category
    Physical Chemistry
    Identifiers
    urn:nbn:se:uu:diva-313407 (URN)10.1063/1.4967810 (DOI)000390118200037 ()
    Funder
    Swedish Energy Agency, 39036-1Swedish Research Council
    Available from: 2017-01-19 Created: 2017-01-19 Last updated: 2019-08-05Bibliographically approved
    2. Insights into the Li-Metal/Organic Carbonate Interfacial Chemistry by Combined First-Principles Theory and X-ray Photoelectron Spectroscopy
    Open this publication in new window or tab >>Insights into the Li-Metal/Organic Carbonate Interfacial Chemistry by Combined First-Principles Theory and X-ray Photoelectron Spectroscopy
    Show others...
    2019 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 123, no 1, p. 347-355Article in journal (Refereed) Published
    Abstract [en]

    X-ray photoelectron spectroscopy (XPS) is a widely used technique to study surfaces and interfaces. In complex chemical systems, however, interpretation of the XPS results and peak assignments is not straightforward. This is not least true for Li-batteries, where XPS yet remains a standard technique for interface characterization. In this work, a combined density functional theory (DFT) and experimental XPS study is carried out to obtain the C 1s and O 1s core-level binding energies of organic carbonate molecules on the surface of Li metal. Decomposition of organic carbonates is frequently encountered in electrochemical cells employing this electrode, contributing to the build up of a complex solid electrolyte interphase (SEI). The goal in this current study is to identify the XPS fingerprints of the formed compounds, degradation pathways, and thereby the early formation stages of the SEI. The contribution of partial atomic charges on the core-ionized atoms and the electrostatic potential due to the surrounding atoms on the core-level binding energies, which is decisive for interpretation of the XPS spectra, are addressed based on the DFT calculations. The results display strong correlations between these two terms and the binding energies, whereas electrostatic potential is found to be the dominating factor. The organic carbonate molecules, decomposed at the surface of the Li metal, are considered based on two different decomposition pathways. The trends of calculated binding energies for products from ethereal carbon-ethereal oxygen bond cleavage in the organic carbonates are better supported when compared to the experimental XPS results.

    Place, publisher, year, edition, pages
    AMER CHEMICAL SOC, 2019
    National Category
    Physical Chemistry Materials Chemistry
    Identifiers
    urn:nbn:se:uu:diva-375877 (URN)10.1021/acs.jpcc.8b07679 (DOI)000455561100036 ()
    Funder
    Swedish Energy Agency, 39036-1Swedish Research CouncilStandUpCarl Tryggers foundation
    Available from: 2019-02-04 Created: 2019-02-04 Last updated: 2019-08-05Bibliographically approved
    3. Density Functional Theory Modeling the Interfacial Chemistry of the LiNO3 Additive for Lithium-Sulfur Batteries by Means of Simulated Photoelectron Spectroscopy
    Open this publication in new window or tab >>Density Functional Theory Modeling the Interfacial Chemistry of the LiNO3 Additive for Lithium-Sulfur Batteries by Means of Simulated Photoelectron Spectroscopy
    2017 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 121, no 42, p. 23324-23332Article in journal (Refereed) Published
    Abstract [en]

    Lithium-sulfur (Li-S) batteries are considered candidates for next-generation energy storage systems due to their high theoretical specific energy. There exist, however, some shortcomings of these batteries, not least the solubility of intermediate polysulfides into the electrolyte generating a so-called "redox shuttle", which gives rise to self-discharge. LiNO3 is therefore frequently used as an electrolyte additive to help suppress this mechanism, but the exact nature of the LiNO3 functionality is still unclear. Here, density functional theory calculations are used to investigate the electronic structure of LiNO3 and a number of likely species (N-2, N2O, LiNO2, Li3N, and Li2N2O2) resulting from the reduction of this additive on the surface of Li metal anode. The N is X-ray photoelectron spectroscopy core level binding energies of these molecules on the surface are calculated in order to compare the results with experimentally reported values. The core level shifts (CLS) of the binding energies are studied to identify possible factors responsible for the position of the peaks. Moreover, solid phases of (cubic) c-Li3N and (hexagonal) alpha-Li3N on the surface of Li metal are considered. The N is binding energies for the bulk phases of Li3N and at the Li3N/Li interfaces display higher values as compared to the Li3N molecule, indicating a clear correlation between the coordination number and the CLS of the solid phases of Li3N.

    National Category
    Materials Chemistry
    Identifiers
    urn:nbn:se:uu:diva-337669 (URN)10.1021/acs.jpcc.7b07847 (DOI)000414114800009 ()
    Funder
    Swedish Energy Agency, 39036-1Carl Tryggers foundation Swedish Research Council, 2014-5984; 2015-05754
    Available from: 2018-01-03 Created: 2018-01-03 Last updated: 2019-08-05Bibliographically approved
    4. Modelling the Polymer Electrolyte/Li-Metal Interface by Molecular Dynamics simulations
    Open this publication in new window or tab >>Modelling the Polymer Electrolyte/Li-Metal Interface by Molecular Dynamics simulations
    2017 (English)In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 234, p. 43-51Article in journal (Refereed) Published
    Abstract [en]

    Solid polymer electrolytes are considered promising candidates for application in Li-metal batteries due to their comparatively high mechanical strength, which can prevent dendrite formation. In this study, we have performed Molecular Dynamics simulations to investigate structural and dynamical properties of a common polymer electrolyte, poly(ethylene oxide) (PEO) doped with LiTFSI salt in the presence of a Li metal surface. Both a physical (solid wall) and a chemical (slab) model of the Li (100) surface have been applied, and the results are also compared with a model of the bulk electrolyte. The average coordination numbers for oxygen atoms around the Li ions are ca. 6 for all investigated systems. However, the calculated Radial Distribution Functions (RDFs) for Li+-(OPEO) and Li+-(OTFSI) show sharper peaks for the Li slab model, indicating a more well-defined coordination sphere for Li+ in this system. This is clearly a surface effect, since the RDF for Li+ in the interface region exhibits sharper peaks than in the bulk region of the same system. The simulations also display a high accumulation of TFSI anions and Li+ cations close to interface regions. This also leads to slower dynamics of the ionic transport in the systems, which have a Li-metal surface present, as seen from the calculated mean-square-displacement functions. The accumulation of ions close to the surface is thus likely to induce a polarization close to the electrode.

    Keywords
    Li-battery, Polymer Electrolyte, Li-metal, Molecular Dynamics
    National Category
    Materials Chemistry Physical Chemistry
    Identifiers
    urn:nbn:se:uu:diva-321177 (URN)10.1016/j.electacta.2017.03.030 (DOI)000398328800006 ()
    Funder
    Swedish Energy Agency, 39036-1Carl Tryggers foundation Swedish Research Council, 2014-5984
    Available from: 2017-05-11 Created: 2017-05-11 Last updated: 2019-08-05Bibliographically approved
    5. Assessing structure and stability of polymer/lithium-metal interfaces from first-principles calculations
    Open this publication in new window or tab >>Assessing structure and stability of polymer/lithium-metal interfaces from first-principles calculations
    Show others...
    2019 (English)In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 7, no 14, p. 8394-8404Article in journal (Refereed) Published
    Abstract [en]

    Solid polymer electrolytes (SPEs) are promising candidates for Li metal battery applications, but the interface between these two categories of materials has so far been studied only to a limited degree. A better understanding of interfacial phenomena, primarily polymer degradation, is essential for improving battery performance. The aim of this study is to get insights into atomistic surface interaction and the early stages of solid electrolyte interphase formation between ionically conductive SPE host polymers and the Li metal electrode. A range of SPE candidates are studied, representative of major host material classes: polyethers, polyalcohols, polyesters, polycarbonates, polyamines and polynitriles. Density functional theory (DFT) calculations are carried out to study the stability and the electronic structure of such polymer/Li interfaces. The adsorption energies indicated a stronger adhesion to Li metal of polymers with ester/carbonate and nitrile functional groups. Together with a higher charge redistribution, a higher reactivity of these polymers is predicted as compared to the other electrolyte hosts. Products such as alkoxides and CO are obtained from the degradation of ester- and carbonate-based polymers by AIMD simulations, in agreement with experimental studies. Analogous to low-molecular-weight organic carbonates, decomposition pathways through C-carbonyl-O-ethereal and C-ethereal-O-ethereal bond cleavage can be assumed, with carbonate-containing fragments being thermodynamically favorable.

    Place, publisher, year, edition, pages
    ROYAL SOC CHEMISTRY, 2019
    National Category
    Materials Chemistry
    Identifiers
    urn:nbn:se:uu:diva-382550 (URN)10.1039/c8ta12147h (DOI)000464414200040 ()
    Funder
    Swedish Energy Agency, 39036-1Swedish Research Council, 621-2014-5984EU, European Research Council, 771777Carl Tryggers foundation
    Available from: 2019-05-10 Created: 2019-05-10 Last updated: 2019-08-05Bibliographically approved
  • 152.
    Ebadi, Mahsa
    et al.
    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.
    Araujo, Carlos Moyses
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Electrolyte decomposition on Li-metal surfaces from first-principles theory2016In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 145, no 20, article id 204701Article in journal (Refereed)
    Abstract [en]

    Animportant feature in Li batteries is the formation of a solid electrolyte interphase (SEI) on the surface of the anode. This film can have a profound effect on the stability and the performance of the device. In this work, we have employed density functional theory combined with implicit solvation models to study the inner layer of SEI formation from the reduction of common organic carbonate electrolyte solvents (ethylene carbonate, propylene carbonate, dimethyl carbonate, and diethyl carbonate) on a Li metal anode surface. Their stability and electronic structure on the Li surface have been investigated. It is found that the CO producing route is energetically more favorable for ethylene and propylene carbonate decomposition. For the two linear solvents, dimethyl and diethyl carbonates, no significant differences are observed between the two considered reduction pathways. Bader charge analyses indicate that 2 e(-) reductions take place in the decomposition of all studied solvents. The density of states calculations demonstrate correlations between the degrees of hybridization between the oxygen of adsorbed solvents and the upper Li atoms on the surface with the trend of the solvent adsorption energies.

  • 153.
    Ebadi, Mahsa
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Costa, Luciano T.
    Univ Fed Fluminense, Dept Fis Quim, Inst Quim, Outeiro Sao Joao Batista S-N, BR-24020150 Niteroi, RJ, Brazil..
    Araujo, C. Moyses
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Brandell, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Modelling the Polymer Electrolyte/Li-Metal Interface by Molecular Dynamics simulations2017In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 234, p. 43-51Article in journal (Refereed)
    Abstract [en]

    Solid polymer electrolytes are considered promising candidates for application in Li-metal batteries due to their comparatively high mechanical strength, which can prevent dendrite formation. In this study, we have performed Molecular Dynamics simulations to investigate structural and dynamical properties of a common polymer electrolyte, poly(ethylene oxide) (PEO) doped with LiTFSI salt in the presence of a Li metal surface. Both a physical (solid wall) and a chemical (slab) model of the Li (100) surface have been applied, and the results are also compared with a model of the bulk electrolyte. The average coordination numbers for oxygen atoms around the Li ions are ca. 6 for all investigated systems. However, the calculated Radial Distribution Functions (RDFs) for Li+-(OPEO) and Li+-(OTFSI) show sharper peaks for the Li slab model, indicating a more well-defined coordination sphere for Li+ in this system. This is clearly a surface effect, since the RDF for Li+ in the interface region exhibits sharper peaks than in the bulk region of the same system. The simulations also display a high accumulation of TFSI anions and Li+ cations close to interface regions. This also leads to slower dynamics of the ionic transport in the systems, which have a Li-metal surface present, as seen from the calculated mean-square-displacement functions. The accumulation of ions close to the surface is thus likely to induce a polarization close to the electrode.

  • 154.
    Ebadi, Mahsa
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Lacey, Matthew
    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.
    Araujo, Carlos Moyses
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Density Functional Theory Modeling the Interfacial Chemistry of the LiNO3 Additive for Lithium-Sulfur Batteries by Means of Simulated Photoelectron Spectroscopy2017In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 121, no 42, p. 23324-23332Article in journal (Refereed)
    Abstract [en]

    Lithium-sulfur (Li-S) batteries are considered candidates for next-generation energy storage systems due to their high theoretical specific energy. There exist, however, some shortcomings of these batteries, not least the solubility of intermediate polysulfides into the electrolyte generating a so-called "redox shuttle", which gives rise to self-discharge. LiNO3 is therefore frequently used as an electrolyte additive to help suppress this mechanism, but the exact nature of the LiNO3 functionality is still unclear. Here, density functional theory calculations are used to investigate the electronic structure of LiNO3 and a number of likely species (N-2, N2O, LiNO2, Li3N, and Li2N2O2) resulting from the reduction of this additive on the surface of Li metal anode. The N is X-ray photoelectron spectroscopy core level binding energies of these molecules on the surface are calculated in order to compare the results with experimentally reported values. The core level shifts (CLS) of the binding energies are studied to identify possible factors responsible for the position of the peaks. Moreover, solid phases of (cubic) c-Li3N and (hexagonal) alpha-Li3N on the surface of Li metal are considered. The N is binding energies for the bulk phases of Li3N and at the Li3N/Li interfaces display higher values as compared to the Li3N molecule, indicating a clear correlation between the coordination number and the CLS of the solid phases of Li3N.

  • 155.
    Ebadi, Mahsa
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Marchiori, Cleber
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Mindemark, Jonas
    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.
    Araujo, Carlos Moyses
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Assessing structure and stability of polymer/lithium-metal interfaces from first-principles calculations2019In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 7, no 14, p. 8394-8404Article in journal (Refereed)
    Abstract [en]

    Solid polymer electrolytes (SPEs) are promising candidates for Li metal battery applications, but the interface between these two categories of materials has so far been studied only to a limited degree. A better understanding of interfacial phenomena, primarily polymer degradation, is essential for improving battery performance. The aim of this study is to get insights into atomistic surface interaction and the early stages of solid electrolyte interphase formation between ionically conductive SPE host polymers and the Li metal electrode. A range of SPE candidates are studied, representative of major host material classes: polyethers, polyalcohols, polyesters, polycarbonates, polyamines and polynitriles. Density functional theory (DFT) calculations are carried out to study the stability and the electronic structure of such polymer/Li interfaces. The adsorption energies indicated a stronger adhesion to Li metal of polymers with ester/carbonate and nitrile functional groups. Together with a higher charge redistribution, a higher reactivity of these polymers is predicted as compared to the other electrolyte hosts. Products such as alkoxides and CO are obtained from the degradation of ester- and carbonate-based polymers by AIMD simulations, in agreement with experimental studies. Analogous to low-molecular-weight organic carbonates, decomposition pathways through C-carbonyl-O-ethereal and C-ethereal-O-ethereal bond cleavage can be assumed, with carbonate-containing fragments being thermodynamically favorable.

  • 156.
    Ebadi, Mahsa
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Nasser, Antoine
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory. ENSTA ParisTech, 828 Blvd Marechaux, F-91120 Palaiseau, France.
    Carboni, Marco
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Younesi, Reza
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Marchiori, Cleber
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Brandell, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Araujo, Carlos Moyses
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Insights into the Li-Metal/Organic Carbonate Interfacial Chemistry by Combined First-Principles Theory and X-ray Photoelectron Spectroscopy2019In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 123, no 1, p. 347-355Article in journal (Refereed)
    Abstract [en]

    X-ray photoelectron spectroscopy (XPS) is a widely used technique to study surfaces and interfaces. In complex chemical systems, however, interpretation of the XPS results and peak assignments is not straightforward. This is not least true for Li-batteries, where XPS yet remains a standard technique for interface characterization. In this work, a combined density functional theory (DFT) and experimental XPS study is carried out to obtain the C 1s and O 1s core-level binding energies of organic carbonate molecules on the surface of Li metal. Decomposition of organic carbonates is frequently encountered in electrochemical cells employing this electrode, contributing to the build up of a complex solid electrolyte interphase (SEI). The goal in this current study is to identify the XPS fingerprints of the formed compounds, degradation pathways, and thereby the early formation stages of the SEI. The contribution of partial atomic charges on the core-ionized atoms and the electrostatic potential due to the surrounding atoms on the core-level binding energies, which is decisive for interpretation of the XPS spectra, are addressed based on the DFT calculations. The results display strong correlations between these two terms and the binding energies, whereas electrostatic potential is found to be the dominating factor. The organic carbonate molecules, decomposed at the surface of the Li metal, are considered based on two different decomposition pathways. The trends of calculated binding energies for products from ethereal carbon-ethereal oxygen bond cleavage in the organic carbonates are better supported when compared to the experimental XPS results.

  • 157.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Anodes for lithium and sodium batteries – and their challenging interfaces2015Conference paper (Refereed)
  • 158.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Anodes for lithium-based batteries – how difficult could this be?2014Conference paper (Refereed)
  • 159.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Batteries for Energy Storage2017Conference paper (Other academic)
    Abstract [en]

    There is a multitude of different materials that can be used as anode and cathode materials for Li- and Na-based batteries. Some examples are carbon materials for the negative electrode and transition-metal oxides for the positive electrode. To increase the capacity of a Li-ion battery, the positive electrode is the bottleneck, while the bottleneck for the Na-ion battery is the negative electrode. For both types of batteries the electrolyte material is vital for the power capability of the battery and for the safety of a battery cell.

     

    In this lecture, I will describe how different in-operando methods probing the atomic structure of battery materials can lead to insights in the subtleties of how small changes in parameters - such as synthesis conditions, particle morphology and size of different materials - can influence the function of a battery. All the material components have to be probed in a real battery context, and to understand their true function in this context, synchrotron-radiation as well as neutron diffraction, but also different spectroscopic methods, are important and complementary tools.

     

    A special focus will be given to intercalation and insertion materials: solids that can host the mobile lithium or sodium ions. The interface between the electrode and electrolyte materials will also be discussed by describing the so-called SEI (Solid Electrolyte Interphase), which is so important for the function of Li-ion and Na-ion batteries and which is formed during electrochemical cycling. Synchrotron-radiation (and neutron) methods are, in general, vital and necessary tools for the understanding of the complex reactions taking place both in bulk materials and at the interfaces between the components in a battery. Results from in-operando studies will be given to exemplify the current status of the battery research field.

  • 160.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Burried Interfaces in Anode Materials for Li-Ion Batteries- Can they influence EVs?2015Conference paper (Refereed)
  • 161.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Depth profiling through electrode/electrolyte interfaces2014Conference paper (Refereed)
  • 162.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Eco-Friendly Nano-materials for Li- and Na-ion Batteries”, International conference on functional materials: nano and composite functional materials2014Conference paper (Refereed)
  • 163.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    En stjärna på kemisternas himmel: I Lund står numera världens vackraste synkrotron med ett för kemister mycket lovande innehåll2017Other (Other (popular science, discussion, etc.))
  • 164.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    HAXPES and HPPES – some examples of interfacial reactions in Li-based batteries2015Conference paper (Refereed)
  • 165.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Hunting Down Eco-Friendly Materials for Li- and Na-ion Batteries2014Conference paper (Refereed)
  • 166.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    In operando neutron diffraction studies of battery materials2017In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 253Article in journal (Other academic)
  • 167.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    In situ Neutron Diffraction of  Battery Materials2017Conference paper (Refereed)
    Abstract [en]

    The interest of performing in operando neutron diffraction experiments for lithium ion batteries has increased significantly over the past few years. The method is still not nearly as popular as in operando X-ray diffraction. A major contributor to this is the high difficulty of constructing an electrochemical cell which balances both electrochemical performance, quality of the obtained diffraction pattern and cost of construction. Up until now most work has been performed on, often complex, custom cells built to target a specific feature such as fast cycling at the cost of data quality or data quality with high material loading [1-3]. A significant amount of work has been performed within our group on developing multiple varieties of electrochemical cells for operando neutron diffraction. Given the nature of neutron diffraction it is extremely difficult to develop a single cell to suit all objectives and materials. To this end we have designed two vastly different operando cells; a large wound 18650-like cell [4] and a smaller, cheaper coin cell design. The 18650-like wound cell can contain up to 4 g of active material, is able to be cycled at faster rates and provides a diffraction pattern which is of high enough quality to extract accurate structural parameters. It does, however, require expensive deuterated electrolyte and specialised equipment. Alternatively, the coin cell design is cheap, does not require deuterated electrolyte, can provide good quality diffraction and reasonable electrochemical cycling rates. It is anticipated that the coin cell design will make neutron diffraction accessible to more research groups and also presents a viable cell design for operando neutron diffraction studies of sodium ion cells. Using LiFePO4, LiNi0.5Mn1.5O4 and Li0.18Sr0.66Ti0.5Nb0.5O3 as case study materials this contribution will focus on the operando neutron diffraction results obtained from both cells, thus exploring the core strengths and potential of each design.

  • 168.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Inorganic chemistry and energy storage for a better environment2017Conference paper (Other academic)
    Abstract [en]

    There are many possibilities to suggest new materials for lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). LIBs are key components for electrification of road vehicles and dominate the market for portable electronics. They consist primarily of insertion compounds where lithium can enter the atomic inorganic host structure of both the negative and positive electrode, respectively. The positive electrode material is primarily the bottleneck for increasing the whole energy density of the LIB. The scientific literature is therefore full of descriptions of inorganic materials such as oxides, phosphates, silicates, sulfates, etc. for the positive electrode. The negative electrode is, however, dominated by carbonaceous materials where attempts to increase the amount of silicon can support the development of more energy dense batteries.

    SIBs are similar to LIBs but with fewer options of insertion materials due to the larger sodium-ion. SIBs have recently become a flowering research topic due to the worry that there will be a shortage of lithium due to geopolitical reasons. Sodium can be found everywhere. This presentation will elaborate on the environmental aspects of how to choose the best inorganic compounds to enable recycling, low battery cost combined with high energy density without jeopardize the safety of the battery. Are these parameters even possible to combine in the same battery? The battery cells based on inorganic compounds are compared to those based on new ideas on making paper batteries with electronically/ionically conducting polymers and of organic batteries.

    The idea is of the presentation is simply to give a review of the field and to show how knowledge in inorganic chemistry is vital for better batteries but also for a better environment. The examples are based on the long experience in this field obtained within the Ångström Advanced Battery Centre at Uppsala University. Different methods describing the dynamic processes going on during battery operation will be discussed.

  • 169.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Interfaces and interphases in battery materials probed by PES and soft X-ray techniques2016In: Munich Battery Discussions, 2016Conference paper (Refereed)
  • 170.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Interfaces in Li-ion and Na-ion batteries - what more do we need to understand?2018In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 255Article in journal (Other academic)
  • 171.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Light on battery materials for light2015Conference paper (Other academic)
  • 172.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    nterfaces in batteries - combination of soft and hard X-rays to depth profile the SEI on different negative electrodes in Li- and Na-based batteries2014Conference paper (Refereed)
  • 173.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Silicon and its interfacial reactions.2014Conference paper (Refereed)
  • 174.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Silicon as negative electrode - what more can we do make it work?2017Conference paper (Refereed)
  • 175.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Structures in Motion - in situ Studies of Future Battery Concepts Crystallography – Bridging materials and molecules in modern chemistry2014Conference paper (Other academic)
  • 176.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    THE SEI REVISITED – WHAT DO WE KNOW ABOUT INTERFACES AND INTERPHASES?2017Conference paper (Refereed)
    Abstract [en]

    Introduction

    The Solid Electrolyte Interphase (SEI) and other interfaces in lithium- and sodium ion batteries are despite of many scientific studies still attracting a lot of interest. This presentation aims at reviewing why interfaces in batteries are so crucial for the function, thermal stability, lifetime and ageing of a battery.

         Characterizing interfaces in batteries is both simple and difficult. It is simple in the sense that it is easy to take a battery apart and then use different techniques to study the composition and morphology of interfaces of electrodes and separators post mortem. It is, however, difficult to study in situ how an interface forms and evolves during battery operation.

         The SEI on negative electrodes can be described as a mixture of inorganic and organic compounds where the inorganic compounds are formed closer to the electrode surface. The layer is a consequence of the low potential – close of that of lithium – where for lithium-ion batteries the reduction of the thermodynamically instable organic solvent (below 0.8V vs. Li+/Li) is taking place. There are even descriptions of the SEI consisting of an inner, more dense inorganic layer, where electrons can tunnel through until a certain thickness of the layer has been obtained where the SEI becomes electronically insulating but where ions can penetrate. How the different SEI-compounds interplay to form a well-functioning layer is not yet clear.

     

    Experimental

    The results shown are mainly based on electrochemical cycling combined with photoelectron spectroscopy (PES) results; both in house and synchrotron based. PES has been performed both at the Helmholtz Zentrum Bessy, Germany, and at Diamond UK. The advantage with synchrotron radiation is the possibility to tune the incoming photon energy to reach into a surface at different depths.

    Results and discussion

    The result and discussion will be based on a number of thesis produced at Uppsala University with the aim to answer the following questions:

        Will the electrolyte salt influence the interfaces formed in batteries? Yes. Examples will be given for both lithium and sodium batteries.

        Will the electrode material influence the SEI composition? Not very much but to some extent.

        Is particle size and morphology important for SEI formation?

        What is a good SEI former? Is it better to have an additive in the electrolyte forming the SEI or can the binder be just as good?

        How thick is the SEI? What does the buried interface between the SEI and the electrode look like?

         How is the conditions for a stable interface on a positive electrode? How can metal-ion dissolution be prevented?

     

    There are results trying to answer all these questions which will be discussed in the presentation.

     

    Conclusions

    Interfaces in batteries are complex. They are formed electrochemically or chemically. A well-functioning interface protect from unwanted side reactions. New methods are needed to understand the true formation in situ and to better describe the function of interfaces.

     

    Acknowledgments

    To all colleagues and former post doc and PhD students that have contributed to this work. Funding agencies such as the Swedish Research Council, The Swedish Energy Agency, Horizon2020, FP7, Vinnova, and StandUp for Energy.

  • 177.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Understanding Battery Interfaces2015Conference paper (Refereed)
  • 178.
    Edström, Kristina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Andersson, A.M.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Bishop, A.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Fransson, L.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Lindgren, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry. strukturkemi.
    Hussénius, A
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Carbon electrode morphology and thermal stability of the passivation layer.2001In: J. Power Sources, ISSN 0378-7753, Vol. 97-98, p. 87-Article in journal (Refereed)
    Abstract [en]

    Thermal stability of the solid electrolyte interface (SEI)-layers formed on graphite, mesocarbon microbeads and carbon-black anodes is shown to be dependent on the type lithium salt used in the electrolyte. Exothermic breakdown of the passivation layers

  • 179.
    Edström, Kristina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Asfaw, Habtom Desta
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Ma, Yue
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Development of freestanding electrodes for Li-ion anodes2016Conference paper (Refereed)
  • 180.
    Edström, Kristina
    et al.
    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 Materials Chemistry, Structural Chemistry.
    Gustafsson, Torbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Electrodeposition as a Tool for 3D Microbattery Fabrication2011In: The Electrochemical Society interface, ISSN 1064-8208, Vol. 20, no 2, p. 41-46Article in journal (Refereed)
  • 181.
    Edström, Kristina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Brant, William
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Probing the origins of electrochemical properties in electrodes for lithium ion batteries through in operando diffraction2017Conference paper (Other academic)
    Abstract [en]

    In operando diffraction methods are widely employed to qualitatively follow the reaction progression in operating battery electrodes. However, performing thorough structural analysis with the aim of understanding the origins of battery performance during electrochemical cycling is significantly less common. There exists a unique opportunity to further exploit in operando diffraction to extract detailed information on the dynamic changes taking place to the electrode materials during battery operation. With careful experimental design, in operando methods provide a unique perspective on understanding the electrochemical processes in electrode materials. Tracking the rate of phase conversion throughout a battery electrode, for example, provides insight into the competing sources of resistance in an electrode under different cycling conditions. Further, subtleties in the electrochemical reaction of battery electrodes, such as differences in structural changes between lithium insertion and extraction from a host material, can be identified.

    By changing the focus from simple phase identification towards more detailed structural analyses, in operando neutron diffraction becomes increasingly attractive. While there has been rapidly growing interest in performing in operando neutron diffraction experiments for lithium ion batteries, it remains a relatively inaccessible technique due to the difficulty of preparing custom cells with adequate electrochemical performance. Multiple custom cells inspired by commercial cell designs have been investigated within our group with the aim of fine tuning the electrochemical performance while maintaining high quality diffraction data for Rietveld analysis.

    Using LiFePO4, LiNi0.5Mn1.5O4 and LiFeSO4F as case study materials, this contribution will focus on investigations of electrochemical properties of battery electrodes using the dynamic structural response taking place during cell operation.

  • 182.
    Edström, Kristina
    et al.
    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.
    Interfaces and Interphases in Li- and Na- batteries2017Conference paper (Refereed)
    Abstract [en]

    There are many complex reactions taking place in lithium (LIB) and sodium-ion batteries (SIB). Some of these are unique for the SIBs and some are similar to the reactions taking place in LIBs. One of the main areas of research at the Ångström Advanced Battery Centre (ÅABC) at Uppsala University is to investigate the electrolyte/electrode interface, including the solid-electrolyte interphase (SEI) on the anode and the cathode electrolyte interface (CEI) on the cathode, in rechargeable batteries. We have performed several studies using in-house and synchrotron-based photoelectron spectroscopy, such as hard X-ray Photoelectron Spectroscopy (HAXPES), in order to elucidate the subtle depth profile composition of SEI and SPI and how they are influenced by electrochemical cycling and how this influence the performance of SIBs.

    We have investigated many different categories of electrode materials: i.e. conversion, alloying, and insertion anodes as well as metal-oxide and phosphate cathodes. This presentation will describe how the SEI will be on the negative electrodes will be influenced by temperature, the electrolyte salt and battery cycling conditions, and the cathode composition.

    An in-depth discussion will be made comparing the interfaces and interphases in LIBs with those for SIBs.

    Acknowledgements

    All my students and post docs who have worked and are still working on interface studies are acknowledged for their contributions: Bertrand Philippe, Maria Hahlin, Julia Maibach, Sara Malmgren, Katarzyna Ciosek Högström, Fredrik Lindgren, and Chao Xu. The funding from the Swedish Energy Agency as well as the Swedish Research Council is highly appreciated.

    References

    [1] Bertrand Philippe, Thesis Upsaliensis (www.uu.se) 2013

    [2] Siham Doubaji, Bertrand Philippe, Ismael Saadoune, Mihaela Gorgoi, Torbjorn Gustafsson, Abderrahim Solhy, Mario Valvo, Håkan Rensmo, Kristina Edström, ChemSusChem, 2016, 9, pp  97-108.

    [3] Sara Malmgren, Thesis Upsalienses (www.uu.se) 2013.

    [4] Katarzyna Ciosek, Thesis Upsaliensis (www.uu.se) 2015

    [5] Fredrik Lindgren, Thesis Upsalienses (www.uu.se) 2016

    [6] Chao Xu, et al., Chem. Mater., 2015, 27 (7), pp 2591–2599

  • 183.
    Edström, Kristina
    et al.
    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.
    Aktekin, Burak
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Nordh, Tim
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Lacey, Matthew
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Liivat, Anti
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Reach MAX: Reach maximum volymetric capacity for lithium batteries with high voltage cathodes2017Conference paper (Other academic)
  • 184.
    Edström, Kristina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Maibach, Julia
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Electrode/electrolyte interfaces in lithium and sodium batteries2017Conference paper (Refereed)
    Abstract [en]

    Lithium-ion batteries (LIB) and sodium-ion batteries (SIB) and their materials is today a large research area due to the practical need for efficient energy storage. SIBs show, compared to LIBs, unique electrochemical reactions that mechanistically need to be understood. The kind of materials that can host sodium ions are, for instance, structurally different from the negative and positive electrode materials for LIBs. Also interfacial reactions occurring between the electrode and the electrolyte are different from LIBs.

     

    To understand the chemical properties of electrolyte/electrode interfaces in LIBs and SIBs is one of the core research activities at the Ångström Advanced Battery Centre (ÅABC), Uppsala University. It is at these interfaces, the solid-electrolyte interphase (SEI) on the anode and the cathode electrolyte interface (CEI) on the cathode, charge transfer reactions take place, unwanted side reactions might start and the stability of the interface also influence the thermal stability of the battery. Careful characterization is therefore needed as a base for creating new and more stable interfaces for prolonged battery life. In this presentation we will make a review of several studies we have performed combining electrochemical characterization with in-house and synchrotron-based photoelectron spectroscopy (such as hard X-ray Photoelectron Spectroscopy, HAXPES). We will primarily dwell on the difference in chemical composition of the SEI of anodes used in LIBs and SIBs, respectively. We will also give some examples of ways to improve cycle life: the role of the electrolyte salt, electrolyte additives, but also of ways to protect electrode particle surfaces.

     

    We have investigated materials from three different categories of anodes: i.e. conversion, alloying, and insertion anodes. Our HAXPES results on Fe2O3 as a conversion anode material indicated that the SEI on Fe2O3 anode is thicker and more homogeneous in a SIB compared to that in an analogue Li-ion battery.1 We will discuss our work of silicon anodes for LIBs and we will discuss the dissolution of the SEI components in a SIB which is larger than for a LIB2. We will discuss the results which show that the SEI on a carbonacous anode in a SIB is inferior to that of the LIB counterpart.

     

    The interfaces of positive electrodes are also important. Often corrosion products will form during battery cycling leading to metal dissolution and poisoning of the negative electrode. We will also here compare the interfaces of Ni- and Mn-based oxide cathodes for LIBs and SIBs3.

    .

     

    References:

    [1] B. Philippe; M. Valvo; F. Lindgren; H. Rensmo; K. Edström, Chem. Mater. 2014, 26, 5028–5041.

    [2] R. Mogensen, D. Brandell, R. Younesi, ACS Energy Lett., 2016, 1, 1173–1178.

    [3] S. Doubaji, B. Philippe, I. Saadoune, M. Gorgoi, T. Gustafsson, A. Solhy, Mario Valvo, H. Rensmo, K. Edström. ChemSusChem, 2916, 9, 97-108.

     

  • 185.
    Edström, Kristina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Maibach, Julia
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Xu, Chao
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Åhlund, John
    Scienta.
    Gustafsson, Torbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Siegbahn, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Rensmo, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Hahlin, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Recent progress in high pressure analyser and experimental method development applied to liquid/solid interface studies2015Conference paper (Refereed)
  • 186.
    Edström, Kristina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Pan, Ruijun
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Wang, Zhaouhui
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Separators As a Tool for Enhanced Battery Performance2019In: International Battery Association 2019: Batteries and Energy Storage / [ed] The electrochemical Society, La Jolla, 2019, article id 117872Conference paper (Refereed)
  • 187.
    Edström, Kristina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Philippe, Bertrand
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Younesi, Reza
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Sodium batteries and their interfaces2017Conference paper (Other academic)
  • 188.
    Edström, Kristina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Xu, Chao
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Lindgregn, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Yue, Ma
    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.
    Silicon anodes and electrolyte interactions2016Conference paper (Refereed)
  • 189.
    Edström, Kristina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Younesi, Reza
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    State of the art knowledge about interfaces and interphases in lithium and sodium batteries2018In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 256Article in journal (Other academic)
  • 190.
    Edström, Kristina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Yue, Ma
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Flash, Size Tunable Synthesis of SnO2 Nanocrystals Encapsulated in 3d Macroporous Carbon and Its Pseudocapacitive Contribution to High Performance Li+ Storage2015Conference paper (Refereed)
  • 191.
    Egorov, A. V.
    et al.
    St Petersburg State Univ, St Petersburg 199034, Russia.
    Brodskaya, E. N.
    St Petersburg State Univ, St Petersburg 199034, Russia.
    Laaksonen, Aatto
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry. Stockholm Univ, Arrhenius Lab, Dept Mat & Environm Chem, S-10691 Stockholm, Sweden.
    The Effect of Single-Atomic Ions on the Melting of Microscopic Ice Particles According to Molecular Dynamics Data2018In: Colloid Journal of the Russian Academy of Science, ISSN 1061-933X, E-ISSN 1608-3067, Vol. 80, no 5, p. 484-491Article in journal (Refereed)
    Abstract [en]

    Molecular dynamics simulation of microscopic ice particles containing Ca2+, F-, Cl-, Na+, and Li+ ions has been performed in the temperature range of 20-200 K. For all the systems under consideration, phase and structural transformations accompanying their heating have been studied in detail, and the melting points have been determined. The main attention has been focused on the determination of the mechanisms of the effect of ions on the phase state of microcrystals.

  • 192.
    Ehrenborg, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Investigation of the Cr solubility in the MC phase where M = Ti, Ta2016Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In this work the chromium solubility in MC, and M in Cr3C2 and Cr7C3 carbides in the Ti-Cr-C and Ta-Cr-C system have been examined experimentally. Special attention is given to the cubic MC phase due to its frequent use in industrial cemented carbides. A sample series was made where half of the samples were arc-melted and all samples were heat-treated at different temperatures. By arc-melting some of the samples it was possible to compare the arc-melted and non arc-melted samples to confirm equilibrium. Three phases were expected in each sample. The microstructure was examined by LOM and SEM. The phases were identified by XRD and the amount of Cr in each phase was measured by WDS in FEG-SEM or by microprobe analysis. A higher temperature for the heat-treatment allows more Cr to dissolve in the cubic carbide. Arc-melted samples allow more Cr to dissolve than the same system which has not been arc-melted. The Cr solubility in the cubic carbide in non arc-melted samples at 1400 degree Celcius is 8,1±0,4 at% in (Ti, Cr)C and 7,6±0,3 at% in (Ta, Cr)C. According to the samples the phase diagrams based on thermodynamic calculations are different to experimental data. Therefore, more experimental data should be made to update existing ternary diagrams.

  • 193.
    Ek, Gustav
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    A study of poly(vinyl alcohol) as a solid polymer electrolyte for lithium-ion batteries2016Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The use of solid polymer electrolytes in lithium-ion batteries has the advantage in

    terms of safety and processability, however they often lack in terms of performance.

    This is of major concern in applications where high current densities or rapidly

    changing currents are important. Such applications include electrical vehicles and

    energy storage of the electrical grid to accommodate fluctuations when using

    renewable energy sources such as wind and solar.

    In this study, the use of commercial poly(vinyl alcohol) (PVA) as a solid polymer

    electrolyte for use in lithium-ion batteries has been evaluated. Films were prepared

    using various lithium salts such as lithium bis(trifluoromethane)sulfonimide (LiTFSI)

    and casting techniques. Solvent free films were produced by substituting the solvent

    Dimethyl sulfoxide (DMSO) with water and rigouros drying or by employing a

    hot-pressing technique. The best performing system studied was PVA-LiTFSI-DMSO,

    which reached ionic conductivities of 4.5E-5 S/cm at room temperature and 0.45

    mS/cm at 60 °C. The solvent free films showed a drop of ionic conductivity by

    roughly one order of magnitude compared to films with residual DMSO present. High

    ionic conductivities in PVA-LiTFSI-DMSO electrolytes are thus ascribed to fast lithium

    ion transport through the liquid domain of DMSO, or by plasticizing effects of salt and

    solvent on the polymer.

    Thermal analysis of the films showed a clear plasticizing effect of DMSO by a decrease

    in the glass transition temperature. FTIR analysis showed complexation of all the

    lithium salts investigated with the OH-groups of the polymer by a shift in the

    characteristic frequencies of both salts and polymer.

    For the first time, prototype battery cells containing PVA electrolytes were

    manufactured and evaluated by galvanostatic cycling. PVA-LiTFSI-DMSO showed

    stable cycling performance for 15 cycles. Solvent free electrolytes were also

    investigated but did not result in any stable cycling performance.

  • 194.
    Ekström, Alexander
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Förutsättningar för ökad livslängd av sandlåsöverhettare2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Superheaters suffer large material loss during combustion of waste and biomass, causing a short life time for these expensive components. During combustion, corrosive ash particles are formed and erosion is caused by circulating bed material and sand particles, all contributing to the material loss. This study examines whether corrosion or erosion has the largest effect on this material loss by investigating two superheaters in loop seal during biomass and waste combustion of an 85 MW, Circulating Fluidized Bed (CFB) boiler in Händelö.

    The samples were investigated by SEM/EDX and XRD with regard to material loss and corrosion products. The superheaters have different thermal conditions since the material temperature in the first superheater that the steam passes is lower than in the one that comes after. In this report, a model to determine the tube temperature in steam boiler superheaters is also described due to the fact that the local tube temperature is of great importance of condensation of corrosive gases such as KCl and NaCl.

    Material loss was significantly greater on the cooler superheater compared with the warmer. The material temperatures on the outside of the tubes, were calculated to be about 574 °C for the cooler superheater and about 617°C for the warmer superheater. Overall, all analyzes showed low levels of corrosive substances, although there was a certain corrosion tendency, which indicates that material loss of the superheaters is caused by corrosion-assisted erosion. Lower material temperature of the superheater resulted in a higher degree of condensation of corrosive species such as alkali chlorides, which might have accelerated the erosion.

    The conclusion is that the dominant mechanism of material loss on the superheaters is erosion. 

  • 195.
    Emera, Flory
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Method development for copper dispersion evaluation and copper-based catalysts characterization2013Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    N2O chemisorption technique for copper dispersion determination was developed and optimized for accurate and reproducible results. With this technique, the bulk oxidation of pre-reduced catalyst can be prevented by N2O decomposition at low temperature (30oC). Only surface copper atoms are oxidized. The amount of freshly oxidized surface coppers is determined from H2-back-titration of fixed oxygen.The impact of temperature and time of exposure during oxidation was studied. Measurements made at higher temperature (60oC) resulted in overestimation of copper dispersion due to oxygen diffusion into the bulk and sub-layers. Much longer exposure time may also have an impact on copper dispersion estimation.For accurate results and good precision, it is recommended to work under mild conditions (isothermal oxidation at 30oC for 45 min.The developed method was successfully applied to fresh and spent catalyst. As expected, the copper dispersion for fresh catalyst was significantly higher than copper dispersion for spent catalyst.

  • 196.
    Engelbrecht, Leon
    et al.
    Stellenbosch Univ, Dept Chem & Polymer Sci, Private Bag X1, ZA-7602 Matieland, South Africa;Univ Cagliari, Dept Chem & Geol Sci, I-09042 Monserrato, Italy;Stockholm Univ, Div Phys Chem, Dept Mat & Environm Chem, Arrhenius Lab, S-10691 Stockholm, Sweden.
    Mocci, Francesca
    Univ Cagliari, Dept Chem & Geol Sci, I-09042 Monserrato, Italy.
    Laaksonen, Aatto
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry. Stockholm Univ, Div Phys Chem, Dept Mat & Environm Chem, Arrhenius Lab, S-10691 Stockholm, Sweden;Petru Poni Inst Macromol Chem, Ctr Adv Res Bionanoconjugates & Biopolymers Dept, Aleea Grigore Ghica Voda 41A, Iasi 700487, Romania.
    Koch, Klaus R.
    Stellenbosch Univ, Dept Chem & Polymer Sci, Private Bag X1, ZA-7602 Matieland, South Africa.
    Pt-195 NMR and Molecular Dynamics Simulation Study of the Solvation of [PtCl6](2-) in Water-Methanol and Water-Dimethoxyethane Binary Mixtures2018In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 57, no 19, p. 12025-12037Article in journal (Refereed)
    Abstract [en]

    The experimental Pt-195 NMR chemical shift, delta((195) Pt), of the [PtCl6](2-) anion dissolved in binary mixtures of water and a fully miscible organic solvent is extremely sensitive to the composition of the mixture at room temperature. Significantly nonlinear delta(Pt-195) trends as a function of solvent composition are observed in mixtures of water-methanol, or ethylene glycol, 2methoxyethanol, and 1,2-dimethoxyethane (DME). The extent of the deviation from linearity of the delta((195) Pt) trend depends strongly on the nature of the organic component in these solutions, which broadly suggests preferential solvation of the [PtCl6](2-) anion by the organic molecule. This simplistic interpretation is based on an accepted view pertaining to monovalent cations in similar binary solvent mixtures. To elucidate these phenomena in detail, classical molecular dynamics computer simulations were performed for [PtCl6](2-) in water-methanol and water-DME mixtures using the anionic charge scaling approach to account for the effect of electronic dielectric screening. Our simulations suggest that the simplistic model of preferential solvation of [PtCl6](2-) by the organic component as inferred from nonlinear delta(Pt-195) trends is not entirely accurate, particularly for water-DME mixtures. The delta(Pt-195) trend in these mixtures levels off for high DME mole fractions, which results from apparent preferential location of [PtCl6](2-) anions at the borders of water-rich regions or clusters within these inherently micro-heterogeneous mixtures. By contrast in water-methanol mixtures, apparently less pronounced mixed solvent micro-heterogeneity is found, suggesting the experimental delta(Pt-195) trend is consistent with a more moderate preferential solvation of [PtCl6](2-) anions. This finding underlines the important role of solvent-solvent interactions and micro-heterogeneity in determining the solvation environment of [PtCl6](2-) anions in binary solvent mixtures, probed by highly sensitive Pt-195 NMR. The notion that preferential solvation of [PtCl6](2-) results primarily from competing ion-solvent interactions as generally assumed for monatomic ions, may not be appropriate in general.

  • 197.
    Eriksson, Rickard
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Structural Changes in Lithium Battery Materials Induced by Aging or Usage2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Li-ion batteries have a huge potential for use in electrification of the transportation sector. The major challenge to be met is the limited energy storage capacity of the battery pack: both the amount of energy which can be stored within the space available in the vehicle (defining its range), and the aging of the individual battery cells (determining how long a whole pack can deliver sufficient energy and power to drive the vehicle). This thesis aims to increase our knowledge and understanding of structural changes induced by aging and usage of the Li-ion battery materials involved.

    Aging processes have been studied in commercial-size Li-ion cells with two different chemistries. LiFePO4/graphite cells were aged under different conditions, and thereafter examined at different points along the electrodes by post mortem characterisation using SEM, XPS, XRD and electrochemical characterization in half-cells. The results revealed large differences in degradation behaviour under different aging conditions and in different regions of the same cell. The aging of LiMn2O4-LiCoO2/Li4Ti5O12 cells was studied under two different aging conditions. Post mortem analysis revealed a high degree of Mn/Co mixing within individual particles of the LiMn2O4-LiCoO2 composite electrode.

    Structural changes induced by lithium insertion were studied in two negative electrode materials: in Li0.5Ni0.25TiOPO4 using in situ XRD, and in Ni0.5TiOPO4 using EXAFS, XANES and HAXPES. It was shown that Li0.5Ni0.25TiOPO4 lost most of its long-range-order during lithiation, and that both Ni and Ti were involved in the charge compensation mechanism during lithiation/delithiation of Ni0.5TiOPO4, with small clusters of metal-like Ni forming during lithiation.

    Finally, in situ XRD studies were also made of the reaction pathways to form LiFeSO4F from two sets of reactants: either FeSO4·H2O and LiF, or Li2SO4 and FeF2. During the heat treatment, Li2SO4 and FeF2 react to form FeSO4·H2O and LiF in a first step. In a second step LiFeSO4F is formed. This underlines the importance of the structural similarities between LiFeSO4F and FeSO4·H2O in the formation process of LiFeSO4F.

    List of papers
    1. Analysis of aging of commercial composite metal oxide - Li4Ti5O12 battery cells
    Open this publication in new window or tab >>Analysis of aging of commercial composite metal oxide - Li4Ti5O12 battery cells
    Show others...
    2014 (English)In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 270, p. 131-141Article in journal (Refereed) Published
    Abstract [en]

    Commercial battery cells with Li4Ti5O12 negative electrode and composite metal oxide positive electrode have been analyzed with respect to aging mechanisms. Electrochemical impedance spectroscopy (EIS), differential capacity analysis (dQ/dV), differential voltage analysis (dV/dQ) and scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDX) were used to identify different ageing mechanisms such as lithium inventory loss, loss of active electrode material and surface film growth. The active material of the positive electrode was also examined by X-ray diffraction (XRD). Aging mechanisms were studied for both calendar-aged and cycle-aged cells. Data from half cells prepared from post mortem harvested electrode material, using lithium foil as negative electrode and pouch material as encapsulation, were used as reference to full cell data. Electrochemical analysis of full and half cells combined with material analysis showed to be a powerful method to identify aging mechanisms in this type of commercial cells. The calendar-aged cell showed insignificant aging while the cycle-aged cell showed noticeable loss of positive electrode active material and loss of cyclable lithium, but only minor loss of negative electrode active material. The results imply that Li4Ti5O12 negative electrode material is a good alternative to other materials if high energy density is not the primary goal.

    Keywords
    Hybrid electrical vehicle (HEV), Lithium ion battery, Li4Ti5O12, LiMn2O4, dV/dQ, dQ/dV
    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-235294 (URN)10.1016/j.jpowsour.2014.07.050 (DOI)000342245400017 ()
    Available from: 2014-11-11 Created: 2014-10-30 Last updated: 2017-12-05Bibliographically approved
    2. Non-uniform aging of cycled commercial LiFePO4//graphite cylindrical cells revealed by post-mortem analysis
    Open this publication in new window or tab >>Non-uniform aging of cycled commercial LiFePO4//graphite cylindrical cells revealed by post-mortem analysis
    Show others...
    2014 (English)In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 257, p. 126-137Article in journal (Refereed) Published
    Abstract [en]

    Aging of power-optimized commercial 2.3 Ah cylindrical LiFePO4//graphite cells to be used in hybrid electric vehicle is investigated and compared for three different aging procedures; (i) using a simulated hybrid electric vehicle cycle within a narrow SOC-range, (ii) using a constant-current cycle over a 100% SOC-range, and (iii) stored during three years at 22 degrees C. Postmortem analysis of the cells is performed after full-cell electrochemical characterization and discharge. EIS and capacity measurements are made on different parts of the disassembled cells. Material characterization includes SEM, EDX, HAXPES/XPS and XRD. The most remarkable result is that both cycled cells displayed highly uneven aging primarily of the graphite electrodes, showing large differences between the central parts of the jellyroll compared to the outer parts. The aging variations are identified as differences in capacity and impedance of the graphite electrode, associated with different SEI characteristics. Loss of cyclable lithium is mirrored by a varying degree of lithiation in the positive electrode and electrode slippage. The spatial variation in negative electrode degradation and utilization observed is most likely connected to gradients in temperature and pressure, that can give rise to current density and potential distributions within the jellyroll during cycling.

    Keywords
    Battery aging, LiFePO4/graphite cells, Hybrid electric vehicle, Synchrotron material characterization, Electrode utilization
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-224557 (URN)10.1016/j.jpowsour.2014.01.105 (DOI)000333780000017 ()
    Funder
    Swedish Energy Agency
    Available from: 2014-05-19 Created: 2014-05-14 Last updated: 2017-12-30
    3. Electrochemical lithium ion intercalation in Li 0.5Ni 0.25TiOPO 4 examined by in situ X-ray diffraction
    Open this publication in new window or tab >>Electrochemical lithium ion intercalation in Li 0.5Ni 0.25TiOPO 4 examined by in situ X-ray diffraction
    Show others...
    2012 (English)In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 225, no SI, p. 547-550Article in journal, Meeting abstract (Refereed) Published
    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.

    Keywords
    Batteries, In situ X-ray powder diffraction, Lithium intercalation compounds, Corner sharing, De-lithiation, Electrochemical cycling, Electrochemical lithiation, In-situ, Intermediate phase, Lithiation, Lithium Intercalation, Lithium ions, Long range orders, Monoclinic phase, Phosphate ions, Structural change, Structural transformation, Third phase, Solar cells, X ray diffraction, X ray powder diffraction, Lithium
    National Category
    Natural Sciences Inorganic Chemistry
    Research subject
    Chemistry with specialization in Inorganic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-186837 (URN)10.1016/j.ssi.2011.11.001 (DOI)000311873400113 ()
    Conference
    18th International Conference on Solid State Ionics, July 3 -8, 2011, Warsaw, Poland
    Funder
    StandUp
    Available from: 2012-12-06 Created: 2012-11-29 Last updated: 2017-12-30
    4. Electronic and Structural Changes in Ni0.5TiOPO4 Li-ion Battery Cells Upon First Lithiation and Delithiation, Studied by High-Energy X-ray Spectroscopies
    Open this publication in new window or tab >>Electronic and Structural Changes in Ni0.5TiOPO4 Li-ion Battery Cells Upon First Lithiation and Delithiation, Studied by High-Energy X-ray Spectroscopies
    Show others...
    2015 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 119, no 18, p. 9692-9704Article in journal (Refereed) Published
    National Category
    Inorganic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-243325 (URN)10.1021/jp511170m (DOI)000354339000002 ()
    Funder
    StandUp
    Available from: 2015-02-08 Created: 2015-02-08 Last updated: 2017-12-30
    5. Formation of Tavorite-Type LiFeSO4F Followed by In Situ X-ray Diffraction
    Open this publication in new window or tab >>Formation of Tavorite-Type LiFeSO4F Followed by In Situ X-ray Diffraction
    Show others...
    2015 (English)In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 298, p. 363-368Article in journal (Refereed) Published
    Abstract [en]

    The tavorite-type polymorph of LiFeSO4F has recently attracted substantial attention as a positive elec- trode material for lithium ion batteries. The synthesis of this material is generally considered to rely on a topotactic exchange of water (H2O) for lithium (Li) and fluorine (F) within the structurally similar hy- drated iron sulfate precursor (FeSO4·H2O) when reacted with lithium fluoride (LiF). However, there have also been discussions in the literature regarding the possibility of a non-topotactic reaction mechanism between lithium sulfate (Li2SO4) and iron fluoride (FeF2) in tetraethylene glycol (TEG) as reaction medium. In this work, we use in situ X-ray diffraction to continuously follow the formation of LiFeSO4F from the two suggested precursor mixtures in a setup aimed to mimic the conditions of a solvothermal autoclave synthesis. It is demonstrated that LiFeSO4F is formed directly from FeSO4·H2O and LiF, in agreement with the proposed topotactic mechanism. The Li2SO4 and FeF2 precursors, on the other hand, are shown to rapidly transform into FeSO4·H2O and LiF with the water originating from the highly hygroscopic TEG before a subsequent formation of LiFeSO4F is initiated. The results highlight the importance of the FeSO4·H2O precursor in obtaining the tavorite-type LiFeSO4F, as it is observed in both reaction routes.

    National Category
    Inorganic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-243324 (URN)10.1016/j.jpowsour.2015.08.062 (DOI)000362146800044 ()
    Funder
    VINNOVA, P37446-1Swedish Energy Agency, 30769-2Swedish Research Council, C0468101StandUp
    Available from: 2015-02-08 Created: 2015-02-08 Last updated: 2017-12-30
  • 198.
    Eriksson, Rickard
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Lasri, Karima
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Gorgoi, Mihaela
    Helmholtz Zentrum Berlin.
    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.
    Brandell, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Saadoune, Ismael
    LCME, University Cadi Ayyad, Marrakech, Morocco.
    Hahlin, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Electronic and Structural Changes in Ni0.5TiOPO4 Li-ion Battery Cells Upon First Lithiation and Delithiation, Studied by High-Energy X-ray Spectroscopies2015In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 119, no 18, p. 9692-9704Article in journal (Refereed)
  • 199.
    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.

  • 200.
    Eriksson, Rickard
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Sobkowiak, Adam
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Ångström, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Sahlberg, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    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.
    Björefors, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Formation of Tavorite-Type LiFeSO4F Followed by In Situ X-ray Diffraction2015In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 298, p. 363-368Article in journal (Refereed)
    Abstract [en]

    The tavorite-type polymorph of LiFeSO4F has recently attracted substantial attention as a positive elec- trode material for lithium ion batteries. The synthesis of this material is generally considered to rely on a topotactic exchange of water (H2O) for lithium (Li) and fluorine (F) within the structurally similar hy- drated iron sulfate precursor (FeSO4·H2O) when reacted with lithium fluoride (LiF). However, there have also been discussions in the literature regarding the possibility of a non-topotactic reaction mechanism between lithium sulfate (Li2SO4) and iron fluoride (FeF2) in tetraethylene glycol (TEG) as reaction medium. In this work, we use in situ X-ray diffraction to continuously follow the formation of LiFeSO4F from the two suggested precursor mixtures in a setup aimed to mimic the conditions of a solvothermal autoclave synthesis. It is demonstrated that LiFeSO4F is formed directly from FeSO4·H2O and LiF, in agreement with the proposed topotactic mechanism. The Li2SO4 and FeF2 precursors, on the other hand, are shown to rapidly transform into FeSO4·H2O and LiF with the water originating from the highly hygroscopic TEG before a subsequent formation of LiFeSO4F is initiated. The results highlight the importance of the FeSO4·H2O precursor in obtaining the tavorite-type LiFeSO4F, as it is observed in both reaction routes.

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