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Malmgren, Sara
Publications (10 of 13) Show all publications
Johnson, W. B., Worrell, W. L., Niklasson, G. A., Malmgren, S. & Strömme, M. (2018). Solid-State Devices: Impedance Response of Electrochromic Materials and Devices (3rded.). In: Evgenij Barsoukov and J. Ross Macdonald (Ed.), IMPEDANCE SPECTROSCOPY: Theory, Experiment, and Applications (pp. 247-291). Hoboken,: John Wiley & Sons
Open this publication in new window or tab >>Solid-State Devices: Impedance Response of Electrochromic Materials and Devices
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2018 (English)In: IMPEDANCE SPECTROSCOPY: Theory, Experiment, and Applications / [ed] Evgenij Barsoukov and J. Ross Macdonald, Hoboken,: John Wiley & Sons, 2018, 3rd, p. 247-291Chapter in book (Refereed)
Place, publisher, year, edition, pages
Hoboken,: John Wiley & Sons, 2018 Edition: 3rd
National Category
Nano Technology
Research subject
Engineering Science with specialization in Nanotechnology and Functional Materials
Identifiers
urn:nbn:se:uu:diva-340087 (URN)9781119333173 (ISBN)9781119074083 (ISBN)9781119333180 (ISBN)
Available from: 2018-01-26 Created: 2018-01-26 Last updated: 2018-08-30
Malmgren, S., Green, S. & Niklasson, G. A. (2017). Anomalous diffusion of ions in electrochromic tungsten oxide films. Electrochimica Acta, 247, 252-257
Open this publication in new window or tab >>Anomalous diffusion of ions in electrochromic tungsten oxide films
2017 (English)In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 247, p. 252-257Article in journal (Refereed) Published
Abstract [en]

Amorphous tungsten oxide thinfilms were deposited by sputtering at different O2/Ar ratios onto conducting substrates. Ion intercalation and diffusion in thefilms was studied by electrochemical impedance spectroscopy measurements in the frequency range 10 mHz–100 kHz and for potentials between 1.0 and 3.2 V vs. Li/Li+, using the film as working electrode in a Li+ containing electrolyte. The impedance data were in very good agreement with anomalous diffusion models. Different models were found to be applicable at potentials >1.8 V and <1.8 V. At high potentials ion intercalation was found to be reversible and an anomalous diffusion model describing ion hopping was favored. At low potentials ion intercalation was found to be irreversible and ion trapping takes place. In this latter range an anomalous diffusion model for the case of non-conserved number of charge carriers gave the best fit to experimentaldata. We obtained potential dependent diffusion coefficients in the range from 109 to 1011cm2/s, and anomalous diffusion exponents in the range 0.1 to 0.4, with the films deposited at lower O2/Ar ratios exhibiting the higher values.

Place, publisher, year, edition, pages
Elsevier, 2017
Keywords
Electrochromism impedance spectroscopy anomalous diffusion tungsten oxide
National Category
Materials Engineering
Research subject
Engineering Science with specialization in Solid State Physics
Identifiers
urn:nbn:se:uu:diva-332918 (URN)10.1016/j.electacta.2017.06.079 (DOI)000408582300027 ()
Funder
Swedish Research Council, 2016-03713
Available from: 2017-11-02 Created: 2017-11-02 Last updated: 2018-08-30Bibliographically approved
Wen, R.-T., Malmgren, S., Granqvist, C. G. & Niklasson, G. A. (2017). Degradation Dynamics for Electrochromic WO3 Films under Extended Charge Insertion and Extraction: Unveiling Physicochemical Mechanisms. ACS Applied Materials and Interfaces, 9(14), 12872-12877
Open this publication in new window or tab >>Degradation Dynamics for Electrochromic WO3 Films under Extended Charge Insertion and Extraction: Unveiling Physicochemical Mechanisms
2017 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, no 14, p. 12872-12877Article in journal (Refereed) Published
Abstract [en]

Degradation of electrochromic thin films under extended charge insertion and extraction is a technically important phenomenon for which no in-depth understanding is currently on hand. Here, we report on an explorative study of sputter-deposited WO3 films in a Li-ion-conducting electrolyte by use of cyclic voltammetry, in situ optical transmittance, and impedance spectroscopy. A cycling-dependent decrease of the charge capacity could be accurately modeled by a power-law function, and impedance spectroscopy gave evidence for anomalous diffusion as well as a higher charge transfer resistance during deintercalation than during intercalation. Thus, a consistent conceptual picture emerged for the degradation dynamics; it includes the growth of an interfacial barrier layer and also embraces anomalous diffusion coupled with dispersive power-law chemical kinetics.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2017
Keywords
WO3, thin films, electrochromism, detrapping physicochemical mechanisms
National Category
Materials Engineering Engineering and Technology
Research subject
Engineering Science with specialization in Solid State Physics
Identifiers
urn:nbn:se:uu:diva-322183 (URN)10.1021/acsami.7b01324 (DOI)000399354100082 ()28328195 (PubMedID)
Funder
EU, FP7, Seventh Framework Programme, 267234Swedish Research Council
Available from: 2017-05-17 Created: 2017-05-17 Last updated: 2017-11-02
Kjell, M. H., Malmgren, S., Ciosek, K., Behm, M., Edström, K. & Lindbergh, G. (2013). Comparing aging of graphite/LiFePO4 cells at 22 degrees C and 55 degrees C - Electrochemical and photoelectron spectroscopy studies. Journal of Power Sources, 243, 290-298
Open this publication in new window or tab >>Comparing aging of graphite/LiFePO4 cells at 22 degrees C and 55 degrees C - Electrochemical and photoelectron spectroscopy studies
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2013 (English)In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 243, p. 290-298Article in journal (Refereed) Published
Abstract [en]

Accelerated aging at elevated temperature is commonly used to test lithium-ion battery lifetime, but the effect of an elevated temperature is still not well understood. If aging at elevated temperature would only be faster, but in all other respects equivalent to aging at ambient temperature, cells aged to end-of-life (EOL) at different temperatures would be very similar. The present study compares graphite/LiFePO4-based cells either cycle- or calendar-aged to EOL at 22 degrees C and 55 degrees C. Cells cycled at the two temperatures show differences in electrochemical impedance spectra as well as in X-ray photoelectron spectroscopy (XPS) spectra. These results show that lithium-ion cell aging is a complex set of processes. At elevated temperature, the aging is accelerated in process-specific ways. Furthermore, the XPS results of cycle-aged samples indicate increased deposition of oxygenated LiPF6 decomposition products in both the negative and positive electrode/electrolyte interfaces. The decomposition seems more pronounced at elevated temperature, and largely accelerated by cycling, which could contribute to the observed cell impedance increase.

Keywords
Aging, XPS, LiFePO4, Electrolyte degradation, Lithium-ion battery
National Category
Natural Sciences
Identifiers
urn:nbn:se:uu:diva-211002 (URN)10.1016/j.jpowsour.2013.06.011 (DOI)000324846200038 ()
Funder
StandUp
Available from: 2013-11-20 Created: 2013-11-19 Last updated: 2017-12-30
Malmgren, S., Ciosek, K., Hahlin, M., Gustafsson, T., Gorgoi, M., Rensmo, H. & Edström, K. (2013). Comparing anode and cathode electrode/electrolyte interface composition and morphology using soft and hard X-ray photoelectron spectroscopy. Electrochimica Acta, 97, 23-32
Open this publication in new window or tab >>Comparing anode and cathode electrode/electrolyte interface composition and morphology using soft and hard X-ray photoelectron spectroscopy
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2013 (English)In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 97, p. 23-32Article in journal (Refereed) Published
Abstract [en]

Electrode/electrolyte interface depth profiling was performed on lithiated graphite and delithiated lithium iron phosphate electrodes after electrochemical cycling in a balanced full cell configuration containing a carbonate based LiPF6 electrolyte. The profiling was performed by synchrotron radiation based hard X‑ray photoelectron spectroscopy, HAXPES, and soft X‑ray photoelectron spectroscopy, SOXPES. In this way, the probing depth was varied over a wide range in the order of 2-50 nm. Both more surface and more bulk sensitive investigations than possible using traditional in-house X‑ray photoelectron spectroscopy (XPS) could thus be performed. The composition and morphology of the lithiated graphite anode/electrolyte interface (solid electrolyte interphase, SEI) and the delithiated lithium iron phosphate cathode/electrolyte interface (solid permeable interface, SPI) were compared. In the vicinity of the highly reductive graphite active material in the SEI, low binding energy components like Li2O were found while no obvious composition gradients were observed in the SPI. Both in the cathode SPI and the anode SEI, significant amounts of C-O and P‑F containing compounds were found to deposit during cycling. Evidence for mixing of the porous binder and other SEI/SPI components was observed in both the anode and cathode electrode/electrolyte interfaces. The lithiated graphite SEI was estimated to be of the order of two tens of nanometers, while the cathode SPI thickness was estimated to a few nanometers only. 

National Category
Materials Chemistry
Research subject
Chemistry with specialization in Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-196469 (URN)10.1016/j.electacta.2013.03.010 (DOI)000319024500004 ()
Funder
StandUp
Available from: 2013-03-08 Created: 2013-03-08 Last updated: 2017-12-30
Malmgren, S., Ciosek, K., Lindblad, R., Plogmaker, S., Kühn, J., Rensmo, H., . . . Hahlin, M. (2013). Consequences of Air Exposure on the Lithiated Graphite SEI. Electrochimica Acta, 105, 83-91
Open this publication in new window or tab >>Consequences of Air Exposure on the Lithiated Graphite SEI
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2013 (English)In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 105, p. 83-91Article in journal (Refereed) Published
Abstract [en]

In the present work, consequences of air exposure on the surface composition of one of the most reactive lithium-ion battery components, the lithiated graphite, was investigated using 280–835 eV soft X-ray photoelectron spectroscopy (SOXPES) as well as 1486.7 eV X-ray photoelectron spectroscopy (XPS) (∼2 and ∼10 nm probing depth, respectively). Different depth regions of the solid electrolyte interphase (SEI) of graphite cycled vs. LiFePO4 were thereby examined. Furthermore, the air sensitivity of samples subject to four different combinations of pre-treatments (washed/unwashed and exposed to air before or after vacuum treatment) was explored. The samples showed important changes after exposure to air, which were found to be largely dependent on sample pre-treatment. Changes after exposure of unwashed samples exposed before vacuum treatment were attributed to reactions involving volatile species. On washed, air exposed samples, as well as unwashed samples exposed after vacuum treatment, effects attributed to lithium hydroxide formation in the innermost SEI were observed and suggested to be associated with partial delithiation of the surface region of the lithiated graphite electrode. Moreover, effects that can be attributed to LiPF6 decomposition were observed. However, these effects were less pronounced than those attributed to reactions involving solvent species and the lithiated graphite.

Place, publisher, year, edition, pages
Elsevier, 2013
National Category
Materials Chemistry
Research subject
Chemistry with specialization in Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-196470 (URN)10.1016/j.electacta.2013.04.118 (DOI)
Available from: 2013-03-08 Created: 2013-03-08 Last updated: 2017-12-06
Malmgren, S., Ciosek, K., Lindblad, R., Plogmaker, S., Kühn, J., Rensmo, H., . . . Hahlin, M. (2013). Consequences of air exposure on the lithiated graphite SEI. Electrochimica Acta, 105, 83-91
Open this publication in new window or tab >>Consequences of air exposure on the lithiated graphite SEI
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2013 (English)In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 105, p. 83-91Article in journal (Refereed) Published
Abstract [en]

In the present work, consequences of air exposure on the surface composition of one of the most reactive lithium-ion battery components, the lithiated graphite, was investigated using 280-835 eV soft X-ray photoelectron spectroscopy (SOXPES) as well as 1486.7 eV X-ray photoelectron spectroscopy (XPS) (similar to 2 and similar to 10 nm probing depth, respectively). Different depth regions of the solid electrolyte interphase (SEI) of graphite cycled vs. LiFePO4 were thereby examined. Furthermore, the air sensitivity of samples subject to four different combinations of pre-treatments (washed/unwashed and exposed to air before or after vacuum treatment) was explored. The samples showed important changes after exposure to air, which were found to be largely dependent on sample pre-treatment. Changes after exposure of unwashed samples exposed before vacuum treatment were attributed to reactions involving volatile species. On washed, air exposed samples, as well as unwashed samples exposed after vacuum treatment, effects attributed to lithium hydroxide formation in the innermost SEI were observed and suggested to be associated with partial delithiation of the surface region of the lithiated graphite electrode. Moreover, effects that can be attributed to LiPF6 decomposition were observed. However, these effects were less pronounced than those attributed to reactions involving solvent species and the lithiated graphite. 

Keywords
XPS, SEI, Graphite, Air, LiPF6
National Category
Natural Sciences
Identifiers
urn:nbn:se:uu:diva-208068 (URN)10.1016/j.electacta.2013.04.118 (DOI)000322414800012 ()
Funder
StandUp
Available from: 2013-09-24 Created: 2013-09-23 Last updated: 2017-12-30
Malmgren, S. (2013). Insights into Li-ion Battery and Stainless Steel Interfaces Using Refined Photoelectron Spectroscopy Methodology. (Doctoral dissertation). Uppsala: Acta Universitatis Upsaliensis
Open this publication in new window or tab >>Insights into Li-ion Battery and Stainless Steel Interfaces Using Refined Photoelectron Spectroscopy Methodology
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

If sacrificing some of its material to form a passivating layer at the surface, materials may expand the range of environments where they can be used and further material degradation can decrease. This thesis aims to contribute with insights into passivating layers on especially Li-ion battery anodes (solid electrolyte interphase, SEI) but also on stainless steels, as well as the non-passivating Li-ion battery cathode/electrolyte interface layers (solid permeable interface, SPI). The studies have been performed using new possibilities offered by photoelectron spectroscopy techniques.

Depth gradients in the SEI and SPI layers were studied by combining synchrotron-based hard and soft X-ray photoelectron spectroscopy (HAXPES and SOXPES), which was further developed for Li-ion battery investigations. Stainless steel depth profiles were acquired combining HAXPES with angle resolved X-ray photoelectron spectroscopy (ARXPS).

In the Li-ion battery, organic species were more common in the outermost SEI, while some inorganic compounds were only detected in the more bulk sensitive measurements. No depth gradients were observed in the SPI. The interface between the graphite and the SEI was studied for the first time indicating lithium enrichment at the graphite surface. Furthermore, the influence of the film-forming additive propargyl methanesulphonate (PMS) on the electrode/electrolyte interfaces was studies, and cells cycled to end of life at 22°C and 55°C were compared.

For stainless steels, the thicknesses of the oxide film as well as the nickel enriched metal layer underneath the oxide were determined. A similar methodology was applied to estimate the Li-ion battery SEI thickness.

Finally, experiences from PES methodology work on the Li-ion battery systems are discussed aiming to facilitate further studies of the experimentally challenging electrochemically modified samples.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2013. p. 69
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1031
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-197153 (URN)978-91-554-8624-2 (ISBN)
Public defence
2013-05-03, Häggsalen, Ångströmslaboratoriet, Lägerhyddsvägen 1, Uppsala, 10:15 (English)
Opponent
Supervisors
Available from: 2013-04-12 Created: 2013-03-18 Last updated: 2013-08-30Bibliographically approved
Ciosek Högström, K., Malmgren, S., Hahlin, M., Rensmo, H., Thébault, F., Johansson, P. & Edström, K. (2013). The influence of PMS-additive on the electrode/electrolyte interfaces in LiFePO4/graphite Li-ion batteries. The Journal of Physical Chemistry C, 117(45), 23476-23486
Open this publication in new window or tab >>The influence of PMS-additive on the electrode/electrolyte interfaces in LiFePO4/graphite Li-ion batteries
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2013 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 117, no 45, p. 23476-23486Article in journal (Refereed) Published
Abstract [en]

The influence of a film-forming additive, propargyl methanesulfonate (PMS), on electrochemical performance and electrode/electrolyte interface composition of LiFePO4/graphite Li-ion batteries has been studied. Combined use of in-house X-ray photoelectron spectroscopy (XPS) and soft and hard X-ray photoelectron spectroscopy (PES) enabled nondestructive depth profiling at four different probing depths in the 2-50 nm range. Cells cycled with PMS and LiPF6 in ethylene carbonate/diethyl carbonate (EC/DEC) were compared to a reference sample cycled without PMS. In the first cycle, PMS cells showed a higher irreversible capacity, which is explained by formation of a thicker solid electrolyte interphase (SEI). After three cycles, the SET thicknesses were determined to be 19 and 25 nm for the reference and PMS samples, respectively. After the initial cycling, irreversible losses shown by the PMS cells were lower than those of the reference cell. This could be attributed to a different SET composition and lower differences in the amount of lithium between lithiated and delithiated electrodes for the PMS sample. It was suggested that PMS forms a triple-bonded radical on reduction, which further reacts with the electrolyte. The PMS additive was shown to influence the chemical composition at the positive electrode/electrolyte interface. Thicker interface layers with higher C-O and smaller LiF contributions were formed on LiFePO4 cycled with PMS.

National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-197151 (URN)10.1021/jp4045385 (DOI)000327110500005 ()
Funder
StandUp
Available from: 2013-03-18 Created: 2013-03-18 Last updated: 2017-12-30
Fredriksson, W., Malmgren, S., Gustafsson, T., Gorgoi, M. & Edström, K. (2012). Full depth profile of passive films on 316L stainless steel based on high resolution HAXPES in combination with ARXPS. Applied Surface Science, 258(15), 5790-5797
Open this publication in new window or tab >>Full depth profile of passive films on 316L stainless steel based on high resolution HAXPES in combination with ARXPS
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2012 (English)In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 258, no 15, p. 5790-5797Article in journal (Refereed) Published
Abstract [en]

Depth profiles of the passive films on stainless steel were based on analysis with the non-destructive hard X-ray photoelectron spectroscopy (HAXPES) technique in combination with the angular resolved X-ray photoelectron spectroscopy (ARXPS). The analysis depth with ARXPS is within the passive film thickness, while the HAXPES technique uses higher excitation energies (between 2 and 12 keV) also non-destructively probing the chemical content underneath the film. Depth profiles were done within and underneath the passive film of 316L polarized in acidic solution. The passive film thickness was estimated to 2.6 nm for a sample that was polarized at 0.6 V and the main component in the passive film is, as expected, chromium. From the high resolution HAXPES spectra we suggest chromium in three different oxidation states present. Also for iron three oxides were detected. Gradients of chromium and iron concentrations and oxidation states within the film and an enrichment of nickel within a 0.5 nm layer directly underneath the passive film are some of the results discussed. 

Keywords
Stainless steel, XPS, HAXPES, Passive film
National Category
Inorganic Chemistry
Research subject
Chemistry with specialization in Inorganic Chemistry
Identifiers
urn:nbn:se:uu:diva-173615 (URN)10.1016/j.apsusc.2012.02.099 (DOI)000302135700044 ()
Funder
StandUp
Available from: 2012-05-09 Created: 2012-05-02 Last updated: 2017-12-30
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