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Publications (10 of 33) Show all publications
Blidberg, A., Valvo, M., Alfredsson, M., Tengstedt, C., Gustafsson, T. & Björefors, F. (2019). Electronic changes in poly(3,4-ethylenedioxythiophene)-coated LiFeSO4F during electrochemical lithium extraction. Journal of Power Sources, 418, 84-89
Open this publication in new window or tab >>Electronic changes in poly(3,4-ethylenedioxythiophene)-coated LiFeSO4F during electrochemical lithium extraction
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2019 (English)In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 418, p. 84-89Article in journal (Refereed) Published
Abstract [en]

The redox activity of tavorite LiFeSO4F coated with poly (3,4-ethylenedioxythiophene), i.e. PEDOT, is investigated by means of several spectroscopic techniques. The electronic changes and iron-ligand redox features of this LiFeSO4F-PEDOT composite are probed upon delithiation through X-ray absorption spectroscopy. The PEDOT coating, which is necessary here to obtain enough electrical conductivity for the electrochemical reactions of LiFeSO4F to occur, is electrochemically stable within the voltage window employed for cell cycling. Although the electronic configuration of PEDOT shows also some changes in correspondence of its reduced and oxidized forms after electrochemical conditioning in Li half-cells, its p-type doping is fully retained between 2.7 and 4.1 V with respect to Li+/Li during the first few cycles. An increased iron-ligand interaction is observed in LixFeSO4F during electrochemical lithium extraction, which appears to be a general trend for polyanionic insertion compounds. This finding is crucial for a deeper understanding of a series of oxidation phenomena in Li-ion battery cathode materials and helps paving the way to the exploration of new energy storage materials with improved electrochemical performances.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE BV, 2019
Keywords
Li-ion batteries, Lithium iron sulphate fluoride, Tavorite structure, X-ray absorption spectroscopy, Conductive polymers, Anionic redox processes
National Category
Materials Chemistry Inorganic Chemistry
Identifiers
urn:nbn:se:uu:diva-381567 (URN)10.1016/j.jpowsour.2019.02.039 (DOI)000462420500010 ()
Funder
Swedish Foundation for Strategic Research Swedish Research Council Formas, 245-2014-668Swedish Energy Agency, 2017-013531StandUpÅForsk (Ångpanneföreningen's Foundation for Research and Development)
Available from: 2019-04-16 Created: 2019-04-16 Last updated: 2019-04-16Bibliographically approved
Hedman, J., Morát, J., Johansson, D., Langhammer, E. & Björefors, F. (2018). Nanoplasmonics for online monitoring of lithium-ion batteries. In: : . Paper presented at 69th Annual Meeting of the International Society of Electrochemistry, 2-7 September 2018, Bologna, Italy..
Open this publication in new window or tab >>Nanoplasmonics for online monitoring of lithium-ion batteries
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2018 (English)Conference paper, Poster (with or without abstract) (Other academic)
National Category
Materials Chemistry
Research subject
Chemistry with specialization in Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-374730 (URN)
Conference
69th Annual Meeting of the International Society of Electrochemistry, 2-7 September 2018, Bologna, Italy.
Available from: 2019-01-23 Created: 2019-01-23 Last updated: 2019-01-23
Blidberg, A., Sobkowiak, A., Tengstedt, C., Valvo, M., Gustafsson, T. & Björefors, F. (2017). Identifying the Electrochemical Processes in LiFeSO4F Cathodes for Lithium Ion Batteries. Chemelectrochem, 4(8), 1896-1907
Open this publication in new window or tab >>Identifying the Electrochemical Processes in LiFeSO4F Cathodes for Lithium Ion Batteries
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2017 (English)In: Chemelectrochem, Vol. 4, no 8, p. 1896-1907Article in journal (Other academic) Published
Abstract [en]

The electrochemical performance of tavorite LiFeSO4F can be considerably improved by coating the material with a conducting polymer (poly(3,4-ethylenedioxythiophene); PEDOT). Herein, the mechanisms behind the improved performance are studied systematically by careful electrochemical analysis. It is shown that the PEDOT coating improves the surface reaction kinetics for the Li-ion insertion into LiFeSO4F. For such coated materials no kinetic limitations remain, and a transition from solid state to solution-based diffusion control was observed at 0.6 mA cm−2 (circa C/2). Additionally, the quantity of PEDOT is optimized to balance the weight added by the polymer and the improved electrochemical function. Post mortem analysis shows excellent stability for the LiFeSO4F-PEDOT composite, and maintaining the electronic wiring is the most important factor for stable electrochemical cycling of LiFeSO4F. The insights and the methodology used to determine the rate-controlling steps are readily transferable to other ion-insertion-based electrodes, and the findings are important for the development of improved battery electrodes.

Keywords
Batteries; conducting polymers; electrochemistry; kinetics; lithium
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:uu:diva-317003 (URN)10.1002/celc.201700192 (DOI)000410498700015 ()
Funder
Swedish Foundation for Strategic Research , EM11-0028VINNOVASwedish Research Council Formas, 245-2014-668
Available from: 2017-03-08 Created: 2017-03-08 Last updated: 2017-12-08Bibliographically approved
Blidberg, A., Gustafsson, T., Tengstedt, C., Björefors, F. & Brant, W. R. (2017). Monitoring LixFeSO4F (x = 1, 0.5, 0) Phase Distributions in Operando To Determine Reaction Homogeneity in Porous Battery Electrodes. Chemistry of Materials, 29(17), 7159-7169
Open this publication in new window or tab >>Monitoring LixFeSO4F (x = 1, 0.5, 0) Phase Distributions in Operando To Determine Reaction Homogeneity in Porous Battery Electrodes
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2017 (English)In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 29, no 17, p. 7159-7169Article in journal (Refereed) Published
Abstract [en]

Increasing the energy and power density simultaneously remains a major challenge for improving electrochemical energy storage devices such as Li-ion batteries. Understanding the underlying processes in operating electrodes is decisive to improve their performance. Here, an extension of an in operando X-ray diffraction technique is presented, wherein monitoring the degree of coexistence between crystalline phases in multiphase systems is used to investigate reaction homogeneity in Li-ion batteries. Thereby, a less complicated experimental setup using commercially available laboratory equipment could be employed. By making use of the intrinsic structural properties of tavorite type LiFeSO4F, a promising cathode material for Li-ion batteries, new insights into its nonequilibrium behavior are gained. Differences in the reaction mechanism upon charge and discharge are shown; the influence of adequate electronic wiring for the cycling stability is demonstrated, and the effect of solid state transport on rate performance is highlighted. The methodology is an alternative and complementary approach to the expensive and demanding techniques commonly employed for time-resolved studies of structural changes in operating battery electrodes. The multiphase behavior of LiFeSO4F is commonly observed for other insertion type electrode materials, making the methodology transferable to other new energy storage materials. By expanding the possibilities for investigating complex processes in operating batteries to a larger community, faster progress in both electrode development and fundamental material research can be realized.

Place, publisher, year, edition, pages
American Chemical Society, 2017
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-338351 (URN)10.1021/acs.chemmater.7b01019 (DOI)000410868600017 ()
Available from: 2018-01-08 Created: 2018-01-08 Last updated: 2018-01-25Bibliographically approved
Lindgren, F., Xu, C., Maibach, J., Andersson, A. M., Marcinek, M., Niedzicki, L., . . . Edström, K. (2016). A hard X-ray photoelectron spectroscopy study on the solid electrolyte interphase of a lithium 4,5-dicyano-2- (trifluoromethyl)imidazolide based electrolyte for Si-electrodes. Journal of Power Sources, 301, 105-112
Open this publication in new window or tab >>A hard X-ray photoelectron spectroscopy study on the solid electrolyte interphase of a lithium 4,5-dicyano-2- (trifluoromethyl)imidazolide based electrolyte for Si-electrodes
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2016 (English)In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 301, p. 105-112Article in journal (Other academic) Published
Abstract [en]

This report focuses on the relatively new salt, lithium 4,5-dicyano-2-(trifluoromethyl)imidazolide (LiTDI), and its functionality together with a silicon based composite electrode in a half-cell lithium ion battery context. LiTDI is a promising alternative to the commonly used LiPF6 salt because it does not form HF which can decompose the oxide layer on Si. The formation of a solid electrolyte interphase (SEI) as well as the development of the active Si-particles are investigated during the first electrochemical lithiation and de-lithiation. Characterizations are carried out at different state of charge with scanning electron microscopy (SEM) as well as hard x-ray photoelectron spectroscopy (HAXPES) at two different photon energies. This enables a depth resolved picture of the reaction processes and gives an idea of the chemical buildup of the SEI. The SEI is formed by solvent and LiTDI decomposition products and its composition is similar to SEI formed by other carbonate based electrolytes. The LiTDI salt or its decomposition products are not in itself reactive towards the active Si-material and no unwanted side reactions occurs with the active Si-particles. Despite some decomposition of the LiTDI salt, it is a promising alternative for electrolytes aimed towards Si-based electrodes.

Keywords
Lithium 4, 5-dicyano-2-(trifluoromethyl); imidazolide; Silicon negative electrode; Solid electrolyte interphase; Hard x-ray photoelectron spectroscopy
National Category
Natural Sciences Chemical Sciences
Identifiers
urn:nbn:se:uu:diva-261159 (URN)10.1016/j.jpowsour.2015.09.112 (DOI)000365060500014 ()
Funder
VINNOVA, P37446-1EU, FP7, Seventh Framework ProgrammeEU, FP7, Seventh Framework ProgrammeEU, FP7, Seventh Framework Programme
Available from: 2015-08-31 Created: 2015-08-31 Last updated: 2017-12-04Bibliographically approved
Lindgren, F., Xu, C., Maibach, J., Andersson, A. M., Marcinek, M., Niedzicki, L., . . . Edström, K. (2016). A hard X-ray photoelectron spectroscopy study on the solid electrolyte interphase of a lithium 4,5-dicyano-2-(trifluoromethyl)imidazolide based electrolyte for Si-electrodes. Journal of Power Sources, 301, 105-112
Open this publication in new window or tab >>A hard X-ray photoelectron spectroscopy study on the solid electrolyte interphase of a lithium 4,5-dicyano-2-(trifluoromethyl)imidazolide based electrolyte for Si-electrodes
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2016 (English)In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 301, p. 105-112Article in journal (Refereed) Published
Abstract [en]

This report focuses on the relatively new salt, lithium 4,5-dicyano-2-(trifluoromethyl)imidazolide (LiTDI), and its functionality together with a silicon based composite electrode in a half-cell lithium ion battery context. LiTDI is a promising alternative to the commonly used LiPF6 salt because it does not form HF which can decompose the oxide layer on Si. The formation of a solid electrolyte interphase (SEI) as well as the development of the active Si-particles are investigated during the first electrochemical lithiation and de-lithiation. Characterizations are carried out at different state of charge with scanning electron microscopy (SEM) as well as hard x-ray photoelectron spectroscopy (HAXPES) at two different photon energies. This enables a depth resolved picture of the reaction processes and gives an idea of the chemical buildup of the SEI. The SEI is formed by solvent and LiTDI decomposition products and its composition is similar to SEI formed by other carbonate based electrolytes. The LiTDI salt or its decomposition products are not in itself reactive towards the active Si-material and no unwanted side reactions occurs with the active Si-particles. Despite some decomposition of the LiTDI salt, it is a promising alternative for electrolytes aimed towards Si-based electrodes.

Keywords
lithium 4, 5-dicyano-2-(trifluoromethyl)imidazolide, silicon negative electrode, solid electrolyte interphase, hard x-ray photoelectron spectroscopy
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-312304 (URN)10.1016/j.jpowsour.2015.09.112 (DOI)
Available from: 2017-01-09 Created: 2017-01-09 Last updated: 2017-11-29Bibliographically approved
Lettieri, R., Di Giorgio, F., Colella, A., Magnusson, R., Björefors, F., Placidi, E., . . . Gatto, E. (2016). DPPTE Thiolipid Self-Assembled Monolayer: A Critical Assay. Langmuir, 32(44), 11560-11572
Open this publication in new window or tab >>DPPTE Thiolipid Self-Assembled Monolayer: A Critical Assay
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2016 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 32, no 44, p. 11560-11572Article in journal (Refereed) Published
Abstract [en]

Supported lipid membranes represent an elegant way to design a fluid interface able to mimic the physicochemical properties of biological membranes, with potential biotechnological applications. In this work, a diacyl phospholipid, the 1,2-dipalmitoyl-sn-glycero-3-phosphothioethanol (DPPTE), functionalized with a thiol group, was immobilized on a gold surface. In this molecule, the thiol group, responsible for the Au S bond (45 kJ/mol) is located on the phospholipid polar head, letting the hydrophobic chain protrude from the film. This system is widely used in the literature but is no less challenging, since its characterization is not complete, as several discordant data have been obtained. In this work, the film was characterized by cyclic voltammetry blocking experiments, to verify the SAM formation, and by reductive desorption measurements, to estimate the molecular density of DPPTE on the gold surface. This value has been compared to that obtained by quartz crystal microbalance measurements. Ellipsometry and impedance spectroscopy measurements have been performed to obtain information about the monolayer thickness and capacitance. The film morphology was investigated by atomic force microscopy. Finally, Monte Carlo simulations were carried out, in order to gain molecular information about the morphologies of the DPPTE SAM and compare them to the experimental results. We demonstrate that DPPTE molecules, incubated 18 h below the phase transition temperature (T = 41.1 +/- 0.4 degrees C) in ethanol solution, are able to form a self-assembled monolayer on the gold surface, with domain structures of different order, which have never been reported before. Our results make possible rationalization of the scattered results so far obtained on this system, giving a new insight into the formation of phospholipids SAMs on a gold surface.

National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-310760 (URN)10.1021/acs.langmuir.6b01912 (DOI)000387519000025 ()
Available from: 2016-12-19 Created: 2016-12-19 Last updated: 2017-11-29Bibliographically approved
Lundgren, A., Munktell, S., Lacey, M., Berglin, M. & Björefors, F. (2016). Formation of Gold Nanoparticle Size and Density Gradients via Bipolar Electrochemistry. ChemElectroChem, 3(3), 378-382
Open this publication in new window or tab >>Formation of Gold Nanoparticle Size and Density Gradients via Bipolar Electrochemistry
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2016 (English)In: ChemElectroChem, ISSN 2196-0216, Vol. 3, no 3, p. 378-382Article in journal (Refereed) Published
Abstract [en]

Bipolar electrochemistry is employed to demonstrate the formation of gold nanoparticle size gradients on planar surfaces. By controlling the electric field in a HAuCl4-containing electrolyte, gold was reduced onto 10 nm diameter particles immobilized on pre-modified thiolated bipolar electrode (BPE) templates, resulting in larger particles towards the more cathodic direction. As the gold deposition was the dominating cathodic reaction, the increased size of the nanoparticles also reflected the current distribution on the bipolar electrode. The size gradients were also combined with a second gradient-forming technique to establish nanoparticle surfaces with orthogonal size and density gradients, resulting in a wide range of combinations of small/large and few/many particles on a single bipolar electrode. Such surfaces are valuable in, for example, cell-material interaction and combinatorial studies, where a large number of conditions are probed simultaneously.

National Category
Chemical Sciences Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-277930 (URN)10.1002/celc.201500413 (DOI)000372296100006 ()
Funder
Swedish Research Council Formas, 2010-1572Swedish Research Council, 2009-5398
Available from: 2016-02-26 Created: 2016-02-23 Last updated: 2017-01-25Bibliographically approved
Johansson, D., Andersson, J., Wickman, B., Björefors, F., Sobkowiak, A. & Kasemo, B. (2016). Nanoplasmonic Sensing of Pb-acid and Li-ion Batteries. In: Yurish, SY Malayeri, AD (Ed.), Sensors And Electronic Instrumentation Advances (SEIA): . Paper presented at 2nd International Conference on Sensors and Electronic Instrumentation Advances (SEIA), SEP 22-23, 2016, Barcelona, SPAIN (pp. 57-59). INT FREQUENCY SENSOR ASSOC-IFSA
Open this publication in new window or tab >>Nanoplasmonic Sensing of Pb-acid and Li-ion Batteries
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2016 (English)In: Sensors And Electronic Instrumentation Advances (SEIA) / [ed] Yurish, SY Malayeri, AD, INT FREQUENCY SENSOR ASSOC-IFSA , 2016, p. 57-59Conference paper, Published paper (Refereed)
Abstract [en]

The increasing sophistication and performance of batteries are connected with more complex chemical and physical battery processes and increase the need of more direct and informative measurements, both in the R&D phase and for monitoring and control during operation of vehicles. Todays potentiometric based measurement sensors are not sufficiently accurate for optimal battery sensing. To avoid the built in wide safety margins new, more informative monitoring signals are therefore desired or needed. In this study the optical technology NanoPlasmonic Sensing (NPS) has been used to in-situ monitor the charge and discharge processes of lead-acid and Li-ion batteries. The optical signals were found to correlate well with charging/discharging of both battery technologies.

Place, publisher, year, edition, pages
INT FREQUENCY SENSOR ASSOC-IFSA, 2016
Keywords
Battery management system, Nanoplasmonic sensing, Lead acid, Li-ion, Electrical vehicles, SOC, SOH
National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-346564 (URN)000411474200018 ()978-84-608-9963-1 (ISBN)
Conference
2nd International Conference on Sensors and Electronic Instrumentation Advances (SEIA), SEP 22-23, 2016, Barcelona, SPAIN
Funder
Swedish Energy AgencyVINNOVA
Available from: 2018-03-21 Created: 2018-03-21 Last updated: 2018-03-21Bibliographically approved
Lindgren, F., Xu, C., Niedzicki, L., Marcinek, M., Gustafsson, T., Björefors, F., . . . Younesi, R. (2016). SEI Formation and Interfacial Stability of a Si Electrode in a LiTDI-Salt Based Electrolyte with FEC and VC Additives for Li-Ion Batteries. ACS Applied Materials and Interfaces, 8(24), 15758-15766
Open this publication in new window or tab >>SEI Formation and Interfacial Stability of a Si Electrode in a LiTDI-Salt Based Electrolyte with FEC and VC Additives for Li-Ion Batteries
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2016 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 8, no 24, p. 15758-15766Article in journal (Refereed) Published
Abstract [en]

An electrolyte based on the new salt, lithium 4,5-dicyano-2-(trifluoromethyl)imidazolide (LiTDI), is evaluated in combination with nano-Si composite electrodes for potential use in Li-ion batteries. The additives fluoroethylene carbonate (FEC) and vinylene carbonate (VC) are also added to the electrolyte to enable an efficient SEI formation. By employing hard X-ray photoelectron spectroscopy (HAXPES), the SEI formation and the development of the active material is probed during the first 100 cycles. With this electrolyte formulation, the Si electrode can cycle at 1200 mAh g(-1) for more than 100 cycles at a coulombic efficiency of 99%. With extended cycling, a decrease in Si particle size is observed as well as an increase in silicon oxide amount. As opposed to LiPF6 based electrolytes, this electrolyte or its decomposition products has no side reactions with the active Si material. The present results further acknowledge the positive effects of SEI forming additives. It is suggested that polycarbonates and a high LiF content are favorable components in the SEI over other kinds of carbonates formed by ethylene carbonate (EC) and dimethyl carbonate (DMC) decomposition. This work thus confirms that LiTDI in combination with the investigated additives is a promising salt for Si electrodes in future Li-ion batteries.

Keywords
lithium 4, 5-dicyano-2-(trifluoromethyl)imidazolide, fluoroethylene carbonate, vinylene carbonate, silicon negative electrode, solid electrolyte interphase, hard X-ray photoelectron spectroscopy
National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-299892 (URN)10.1021/acsami.6b02650 (DOI)000378584800099 ()27220376 (PubMedID)
Funder
VINNOVAEU, European Research Council, 312284StandUp
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Kan vara artikeln från manuskriptet http://uu.diva-portal.org/smash/record.jsf?pid=diva2:915177

Available from: 2016-07-29 Created: 2016-07-29 Last updated: 2017-12-30
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