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Li, Z., Mindemark, J., Brandell, D. & Tominaga, Y. (2019). A concentrated poly(ethylene carbonate)/poly(trimethylene carbonate) blend electrolyte for all-solid-state Li battery. Polymer journal, 51(8), 753-760
Open this publication in new window or tab >>A concentrated poly(ethylene carbonate)/poly(trimethylene carbonate) blend electrolyte for all-solid-state Li battery
2019 (English)In: Polymer journal, ISSN 0032-3896, E-ISSN 1349-0540, Vol. 51, no 8, p. 753-760Article in journal (Refereed) Published
Abstract [en]

Electrochemical and ion-transport properties of polymer blend electrolytes comprising poly(ethylene carbonate) (PEC), poly (trimethylene carbonate) (PTMC) and lithium bis(fluorosulfonyl) imide (LiFSI) were studied in this work, and the electrolyte with the best blend composition was applied in all-solid-state Li batteries. The ionic conductivity of both PEC and PTMC single-polymer electrolytes increased with increasing Li salt concentration. All PEC and PTMC blend electrolytes show ionic conductivities on the order of 10(-5) S cm(-1) at 50 degrees C, and the ionic conductivities increase slightly with increasing PEC contents. The PEC6PTMC4-LiFSI 150 mol% electrolyte demonstrated better Li/electrolyte electrochemical and interfacial stability than that of PEC and PTMC single-polymer electrolytes and maintained a polarization as low as 5 mV for up to 200 h during Li metal plating and stripping. A Li vertical bar SPE vertical bar LFP cell with the PEC6PTMC4-LiFSI 150 mol% electrolyte exhibited reversible charge/discharge capacities close to 150 mAh g(-1) at 50 degrees C and a C/10 rate, which is 88% of the theoretical value (170 mAh g(-1)).

Place, publisher, year, edition, pages
NATURE PUBLISHING GROUP, 2019
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:uu:diva-392567 (URN)10.1038/s41428-019-0184-5 (DOI)000478790200005 ()
Funder
StandUp
Available from: 2019-09-10 Created: 2019-09-10 Last updated: 2019-09-10Bibliographically approved
Ebadi, M., Marchiori, C., Mindemark, J., Brandell, D. & Araujo, C. M. (2019). Assessing structure and stability of polymer/lithium-metal interfaces from first-principles calculations. Journal of Materials Chemistry A, 7(14), 8394-8404
Open this publication in new window or tab >>Assessing structure and stability of polymer/lithium-metal interfaces from first-principles calculations
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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
Franco, A. A., Rucci, A., Brandell, D., Frayret, C., Gaberscek, M., Jankowski, P. & Johansson, P. (2019). Boosting Rechargeable Batteries R&D by Multiscale Modeling: Myth or Reality?. Chemical Reviews, 119(7), 4569-4627
Open this publication in new window or tab >>Boosting Rechargeable Batteries R&D by Multiscale Modeling: Myth or Reality?
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2019 (English)In: Chemical Reviews, ISSN 0009-2665, E-ISSN 1520-6890, Vol. 119, no 7, p. 4569-4627Article, review/survey (Refereed) Published
Abstract [en]

This review addresses concepts, approaches, tools, and outcomes of multiscale modeling used to design and optimize the current and next generation rechargeable battery cells. Different kinds of multiscale models are discussed and demystified with a particular emphasis on methodological aspects. The outcome is compared both to results of other modeling strategies as well as to the vast pool of experimental data available. Finally, the main challenges remaining and future developments are discussed.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2019
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-383051 (URN)10.1021/acs.chemrev.8b00239 (DOI)000464768900002 ()30859816 (PubMedID)
Funder
EU, Horizon 2020, 772873EU, Horizon 2020, 686163Swedish Energy Agency, 37671-1
Available from: 2019-05-13 Created: 2019-05-13 Last updated: 2019-05-13Bibliographically approved
Aktekin, B., Valvo, M., Smith, R. I., Sörby, M. H., Marzano, F. L., Zipprich, W., . . . Brant, W. (2019). Cation Ordering and Oxygen Release in LiNi0.5-xMn1.5+xO4-y (LNMO): In Situ Neutron Diffraction and Performance in Li Ion Full Cells. ACS APPLIED ENERGY MATERIALS, 2(5), 3323-3335
Open this publication in new window or tab >>Cation Ordering and Oxygen Release in LiNi0.5-xMn1.5+xO4-y (LNMO): In Situ Neutron Diffraction and Performance in Li Ion Full Cells
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2019 (English)In: ACS APPLIED ENERGY MATERIALS, ISSN 2574-0962, Vol. 2, no 5, p. 3323-3335Article in journal (Refereed) Published
Abstract [en]

Lithium ion cells utilizing LiNi0.5Mn1.5O4 (LNMO) as the positive electrode are prone to fast capacity fading, especially when operated in full cells and at elevated temperatures. The crystal structure of LNMO can adopt a P4(3)32 (cation-ordered) or Fd (3) over barm (disordered) arrangement, and the fading rate of cells is usually mitigated when samples possess the latter structure. However, synthesis conditions leading to disordering also lead to oxygen deficiencies and rock-salt impurities and as a result generate Mn3+. In this study, in situ neutron diffraction was performed on disordered and slightly Mn-rich LNMO samples to follow cation ordering-disordering transformations during heating and cooling. The study shows for the first time that there is not a direct connection between oxygen release and cation disordering, as cation disordering is observed to start prior to oxygen release when the samples are heated in a pure oxygen atmosphere. This result demonstrates that it is possible to tune disordering in LNMO without inducing oxygen deficiencies or forming the rock-salt impurity phase. In the second part of the study, electrochemical testing of samples with different degrees of ordering and oxygen content has been performed in LNMO vertical bar vertical bar LTO (Li4Ti5O12) full cells. The disordered sample exhibits better performance, as has been reported in other studies; however, we observe that all cells behave similarly during the initial period of cycling even when discharged at a 10 C rate, while differences arise only after a period of cycling. Additionally, the differences in fading rate were observed to be time-dependent rather than dependent on the number of cycles. This performance degradation is believed to be related to instabilities in LNMO at higher voltages, that is, in its lower lithiation states. Therefore, it is suggested that future studies should target the individual effects of ordering and oxygen content. It is also suggested that more emphasis during electrochemical testing should be placed on the stability of samples in their delithiated state.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2019
Keywords
high-voltage spinel, neutron diffraction, LNMO, cation ordering, oxygen deficiency
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-387975 (URN)10.1021/acsaem.8b02217 (DOI)000469885300040 ()
Funder
Swedish Energy Agency, 42758-1Swedish Energy Agency, 39043-1StandUp
Available from: 2019-06-27 Created: 2019-06-27 Last updated: 2019-07-29Bibliographically approved
Källquist, I., Naylor, A. J., Baur, C., Chable, J., Kullgren, J., Fichtner, M., . . . Hahlin, M. (2019). Degradation Mechanisms in Li2VO2F Li-Rich Disordered Rock-Salt Cathodes. Chemistry of Materials, 31(16), 6084-6096
Open this publication in new window or tab >>Degradation Mechanisms in Li2VO2F Li-Rich Disordered Rock-Salt Cathodes
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2019 (English)In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 31, no 16, p. 6084-6096Article in journal (Refereed) Published
Abstract [en]

The increased energy density in Li-ion batteries is particularly dependent on the cathode materials that so far have been limiting the overall battery performance. A new class of materials, Li-rich disordered rock salts, has recently been brought forward as promising candidates for next-generation cathodes because of their ability to reversibly cycle more than one Li-ion per transition metal. Several variants of these Li-rich cathode materials have been developed recently and show promising initial capacities, but challenges concerning capacity fade and voltage decay during cycling are yet to be overcome. Mechanisms behind the significant capacity fade of some materials must be understood to allow for the design of new materials in which detrimental reactions can be mitigated. In this study, the origin of the capacity fade in the Li-rich material Li2VO2F is investigated, and it is shown to begin with degradation of the particle surface that spreads inward with continued cycling.

National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-394265 (URN)10.1021/acs.chemmater.9b00829 (DOI)000483435400005 ()
Funder
Swedish Research Council, 2016-03545EU, Horizon 2020, 711792EU, Horizon 2020, 730872StandUpSwedish National Infrastructure for Computing (SNIC)
Available from: 2019-10-09 Created: 2019-10-09 Last updated: 2019-10-09Bibliographically approved
Eriksson, T., Mindemark, J., Yue, M. & Brandell, D. (2019). Effects of nanoparticle addition to poly(epsilon-caprolactone) electrolytes: Crystallinity, conductivity and ambient temperature battery cycling. Electrochimica Acta, 300, 489-496
Open this publication in new window or tab >>Effects of nanoparticle addition to poly(epsilon-caprolactone) electrolytes: Crystallinity, conductivity and ambient temperature battery cycling
2019 (English)In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 300, p. 489-496Article in journal (Refereed) Published
Abstract [en]

It has previously been shown that nanoparticle additives can, in a simple way, significantly improve the ionic conductivity in solid polymer electrolyte systems with the semi-crystalline poly(ethylene oxide) (PEO) as a host material. It has been suggested that the improved ionic conductivity is a result of reduced degree of crystallinity and additional conductivity mechanisms occurring in the material. In this work, this principle is applied to another semi-crystalline polymer host: poly(epsilon-caprolactone) (PCL). This is a polymer with comparable properties (T-g, T-m, etc.) as PEO, and constitute a promising material for use in solid polymer electrolytes for lithium ion batteries. 15 wt% of the respective nanoparticles TiO2, Al2O3 and h-BN have been added to the PCL-LiTFSI solid polymer electrolyte in an attempt to increase the conductivity and achieve stable room temperature cyclability. The crystallinity, ionic conductivity and electrochemical properties were investigated by differential scanning calorimetry, electrochemical impedance spectroscopy and galvanostatic cycling of cells. The results showed that with an addition of 15 wt% Al2O3, the degree of crystallinity is reduced to 6-7% and the ionic conductivity increased to 6-7 x 10(-6) S cm(-1) at room temperature, allowing successful cycling of cells at 30 degrees C, while h-BN did not contribute to similar improvements. The effect of nanoparticles, however, differ significantly from previous observations in PEO systems, which could be explained by different surface-polymer interactions or the degree of ordering in the amorphous phases of the materials.

Place, publisher, year, edition, pages
PERGAMON-ELSEVIER SCIENCE LTD, 2019
Keywords
Li-battery, Solid polymer electrolyte, Polyester, Nanoparticle
National Category
Materials Chemistry Polymer Chemistry
Identifiers
urn:nbn:se:uu:diva-378621 (URN)10.1016/j.electacta.2019.01.117 (DOI)000458488200058 ()
Funder
EU, Horizon 2020, 685716The Swedish Foundation for International Cooperation in Research and Higher Education (STINT), CH2016-6753
Available from: 2019-03-11 Created: 2019-03-11 Last updated: 2019-03-11Bibliographically approved
Grazioli, D., Verners, O., Zadin, V., Brandell, D. & Simone, A. (2019). Electrochemical-mechanical modeling of solid polymer electrolytes: Impact of mechanical stresses on Li-ion battery performance. Elsevier IFAC Publications / IFAC Proceedings series, 296, 1122-1141
Open this publication in new window or tab >>Electrochemical-mechanical modeling of solid polymer electrolytes: Impact of mechanical stresses on Li-ion battery performance
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2019 (English)In: Elsevier IFAC Publications / IFAC Proceedings series, ISSN 1474-6670, Vol. 296, p. 1122-1141Article in journal (Refereed) Published
Abstract [en]

We analyze the effects of mechanical stresses arising in a solid polymer electrolyte (SPE) on the electrochemical performance of the electrolyte component of a lithium ion battery. The SPE is modeled with a coupled ionic conduction-deformation model that allows to investigate the effect of mechanical stresses induced by the redistribution of ions. The analytical solution is determined for a uniform planar cell operating under galvanostatic conditions with and without externally induced deformations. The roles of the polymer stiffness, internally-induced stresses, and thickness of the SPE layer are investigated. The results show that the predictions of the coupled model can strongly deviate from those obtained with an electrochemical model—up to +38% in terms of electrostatic potentialdifference across the electrolyte layer—depending on the combination of material properties and geometrical features. The predicted stress level in the SPE is considerable as it exceeds the threshold experimentally detected for irreversible deformation or fracture to occur in cells not subjected to external loading. We show that stresses induced by external solicitations can reduce the concentration gradient of ions across the electrolyte thickness and prevent salt depletion at the electrode-electrolyte interface.

Keywords
Solid polymer electrolytes, Electrochemical-mechanical coupling, Partial molar volume, Mechanical properties, Battery performance
National Category
Chemical Sciences
Research subject
Chemistry
Identifiers
urn:nbn:se:uu:diva-367335 (URN)10.1016/j.electacta.2018.07.234 (DOI)000454822400127 ()
Funder
EU, FP7, Seventh Framework Programme, 617972
Available from: 2018-11-30 Created: 2018-11-30 Last updated: 2019-01-30Bibliographically approved
Grazioli, D., Zadin, V., Brandell, D. & Simone, A. (2019). Electrochemical-mechanical modeling of solid polymer electrolytes: Stress development and non-uniform electric current density in trench geometry microbatteries. Elsevier IFAC Publications / IFAC Proceedings series, 296, 1142-1162
Open this publication in new window or tab >>Electrochemical-mechanical modeling of solid polymer electrolytes: Stress development and non-uniform electric current density in trench geometry microbatteries
2019 (English)In: Elsevier IFAC Publications / IFAC Proceedings series, ISSN 1474-6670, Vol. 296, p. 1142-1162Article in journal (Refereed) Published
Abstract [en]

We study the effect of mechanical stresses arising in solid polymer electrolytes (SPEs) on the electrochemical performance of lithium-ion (Li-ion) solid-state batteries. Time-dependent finite element analyses of interdigitated plate cells during a discharge process are performed with a constitutive model that couples ionic conduction within the SPE with its deformation field. Due to the coupled nature of the processes taking place in the SPE, the non-uniform ionic concentration profiles that develop during the discharge process induce stresses and deformations within the SPE; at the same time the mechanical loads applied to the cell affect the charge conduction path. Results of a parametric study show that stresses induced by ionic redistribution favor ionic transport and enhance cell conductivity—up to a 15% increase compared to the solution obtained with a purely electrochemical model. We observe that, when the contribution of the mechanical stresses is included in the simulations, the localization of the electric current density at the top of the electrode plates is more pronounced compared to the purely electrochemical model. This suggests that electrode utilization, a limiting factor for the design of three-dimensional battery architectures, depends on the stress field that develops in the SPE. The stress level is indeed significant, and mechanical failure of the polymer might occur during service.

Keywords
Solid polymer electrolytes, Electrochemical-mechanical coupling, Trench geometry microbattery, Battery performance, Non-uniform electric current density
National Category
Chemical Sciences
Identifiers
urn:nbn:se:uu:diva-367339 (URN)10.1016/j.electacta.2018.07.146 (DOI)000454822400128 ()
Funder
EU, FP7, Seventh Framework Programme, 617972
Available from: 2018-11-30 Created: 2018-11-30 Last updated: 2019-01-30Bibliographically approved
Åkerlund, L., Emanuelsson, R., Hernández, G., Ruipérez, F., Casado, N., Brandell, D., . . . Sjödin, M. (2019). In situ Investigations of a Proton Trap Material: A PEDOT-Based Copolymer with Hydroquinone and Pyridine Side Groups Having Robust Cyclability in Organic Electrolytes and Ionic Liquids. ACS Applied Energy Materials, 2(6), 4486-4495
Open this publication in new window or tab >>In situ Investigations of a Proton Trap Material: A PEDOT-Based Copolymer with Hydroquinone and Pyridine Side Groups Having Robust Cyclability in Organic Electrolytes and Ionic Liquids
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2019 (English)In: ACS Applied Energy Materials, ISSN 2574-0962, Vol. 2, no 6, p. 4486-4495Article in journal (Refereed) Published
Abstract [en]

A conducting redox polymer based on PEDOT with hydroquinone and pyridine pendant groups is reported and characterized as a proton trap material. The proton trap functionality, where protons are transferred from the hydroquinone to the pyridine sites, allows for utilization of the inherently high redox potential of the hydroquinone pendant group (3.3 V versus Li0/+) and sustains this reaction by trapping the protons within the polymer, resulting in proton cycling in an aprotic electrolyte. By disconnecting the cycling ion of the anode from the cathode, the choice of anode and electrolyte can be extensively varied and the proton trap copolymer can be used as cathode material for all-organic or metal-organic batteries. In this study, a stable and nonvolatile ionic liquid was introduced as electrolyte media, leading to enhanced cycling stability of the proton trap compared to cycling in acetonitrile, which is attributed to the decreased basicity of the solvent. Various in situ methods allowed for in-depth characterization of the polymer’s properties based on its electronic transitions (UV–vis), temperature-dependent conductivity (bipotentiostatic CV-measurements), and mass change (EQCM) during the redox cycle. Furthermore, FTIR combined with quantum chemical calculations indicate that hydrogen bonding interactions are present for all the hydroquinone and quinone states, explaining the reversible behavior of the copolymer in aprotic electrolytes, both in three-electrode setup and in battery devices. These results demonstrate the proton trap concept as an interesting strategy for high potential organic energy storage materials.

Keywords
conducting redox polymer, organic electronics, renewable energy storage, proton trap, quinone, in situ
National Category
Nano Technology
Research subject
Engineering Science with specialization in Nanotechnology and Functional Materials
Identifiers
urn:nbn:se:uu:diva-389514 (URN)10.1021/acsaem.9b00735 (DOI)000473116600063 ()
Funder
SweGRIDS - Swedish Centre for Smart Grids and Energy StorageSwedish Energy AgencyCarl Tryggers foundation , CTS 17:414Stiftelsen Olle Engkvist ByggmästareSwedish Research Council Formas, 2018-00744Swedish Research Council Formas, 2016-00838
Available from: 2019-07-16 Created: 2019-07-16 Last updated: 2019-09-13Bibliographically approved
Ebadi, M., Nasser, A., Carboni, M., Younesi, R., Marchiori, C., Brandell, D. & Araujo, C. M. (2019). Insights into the Li-Metal/Organic Carbonate Interfacial Chemistry by Combined First-Principles Theory and X-ray Photoelectron Spectroscopy. The Journal of Physical Chemistry C, 123(1), 347-355
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
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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
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-8019-2801

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