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  • 1.
    Blidberg, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi. Uppsala universitet.
    Iron based Li-ion insertion materials for battery applications2016Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Li-ion batteries are currently the most efficient technology available for electrochemical energy storage. The technology has revolutionized the portable electronics market and is becoming a corner stone for large scale applications, such as electric vehicles. It is therefore important to develop materials in which the energy storage relies on abundant redox active species, such as iron. In this thesis, new iron based electrode materials for positive electrodes in Li-ion batteries were investigated. Lithium iron pyrophosphate (Li2FeP2O7) and two polymorphs of lithium iron sulphate fluoride (LiFeSO4F) were studied.

    For Li2FeP2O7, preferred oxidation of iron with different coordination numbers within the crystal structure was studied, and six-coordinated iron was found to be oxidized preferentially at lower potentials compared to five‑coordinated iron. Electrochemical cycling resulted in structural changes of Li2FeP2O7 through an increased Li-Fe mixing in the compound, forming a metastable state during battery operation.

    For tavorite LiFeSO4F, the influence of the amount of a conductive polymer (poly(3,4-ethylenedioxythiophene), or PEDOT) was studied. All the different amounts of PEDOT coating reduced the polarization significantly, but the trade-off between functionality and weight added also has to be considered. Additionally, the effect of densifying the electrodes to different degrees is reported, and was found to have a significant influence on the battery performance. Also triplite LiFeSO4F was coated with PEODT, and it was found that the electrochemical performance improved, but not to the same extent as for tavorite LiFeSO4F. The faster solid state transport of Li-ions in tavorite type LiFeSO4F possibly accounts for the difference in electrochemical performance.

    Together, the results presented herein should be of importance for developing new iron based materials for Li-ion batteries.

    Delarbeid
    1. Structural and Electronic Changes in Li2FeP2O7 during Electrochemical Cycling
    Åpne denne publikasjonen i ny fane eller vindu >>Structural and Electronic Changes in Li2FeP2O7 during Electrochemical Cycling
    Vise andre…
    2015 (engelsk)Inngår i: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 27, nr 11, s. 3801-3804Artikkel i tidsskrift (Fagfellevurdert) Published
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-258346 (URN)10.1021/acs.chemmater.5b00440 (DOI)000356202800004 ()
    Tilgjengelig fra: 2015-07-13 Laget: 2015-07-13 Sist oppdatert: 2017-12-04bibliografisk kontrollert
    2. Battery Performance of PEDOT Coated LiFeSO4F Cathodes with Controlled Porosity
    Åpne denne publikasjonen i ny fane eller vindu >>Battery Performance of PEDOT Coated LiFeSO4F Cathodes with Controlled Porosity
    Vise andre…
    (engelsk)Manuskript (preprint) (Annet vitenskapelig)
    Emneord
    Li-ion battery, cathode material, Tavorite, LiFeSO4F, fluorosulfate, conductive coating, PEDOT, porosity, electrochemical performance
    HSV kategori
    Forskningsprogram
    Kemi med inriktning mot oorganisk kemi
    Identifikatorer
    urn:nbn:se:uu:diva-281262 (URN)
    Forskningsfinansiär
    Swedish Foundation for Strategic Research , EM11-0028
    Tilgjengelig fra: 2016-03-21 Laget: 2016-03-21 Sist oppdatert: 2016-04-05bibliografisk kontrollert
    3. Investigating the Electrochemical Performance of PEDOT-coated Triplite-type LiFeSO4F Cathode Material
    Åpne denne publikasjonen i ny fane eller vindu >>Investigating the Electrochemical Performance of PEDOT-coated Triplite-type LiFeSO4F Cathode Material
    Vise andre…
    (engelsk)Manuskript (preprint) (Annet vitenskapelig)
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-262677 (URN)
    Tilgjengelig fra: 2015-09-18 Laget: 2015-09-18 Sist oppdatert: 2016-03-22
  • 2.
    Blidberg, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Iron Based Materials for Positive Electrodes in Li-ion Batteries: Electrode Dynamics, Electronic Changes, Structural Transformations2017Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Li-ion battery technology is currently the most efficient form of electrochemical energy storage. The commercialization of Li-ion batteries in the early 1990’s revolutionized the portable electronics market, but further improvements are necessary for applications in electric vehicles and load levelling of the electric grid. In this thesis, three new iron based electrode materials for positive electrodes in Li-ion batteries were investigated. Utilizing the redox activity of iron is beneficial over other transition metals due to its abundance in the Earth’s crust. The condensed phosphate Li2FeP2O7 together with two different LiFeSO4F crystal structures that were studied herein each have their own advantageous, challenges, and scientific questions, and the combined insights gained from the different materials expand the current understanding of Li-ion battery electrodes.

    The surface reaction kinetics of all three compounds was evaluated by coating them with a conductive polymer layer consisting of poly(3,4-ethylenedioxythiophene), PEDOT. Both LiFeSO4F polymorphs showed reduced polarization and increased charge storage capacity upon PEDOT coating, showing the importance of controlling the surface kinetics for this class of compounds. In contrast, the electrochemical performance of PEDOT coated Li2FeP2O7 was at best unchanged. The differences highlight that different rate limiting steps prevail for different Li-ion insertion materials.

    In addition to the electrochemical properties of the new iron based energy storage materials, also their underlying material properties were investigated. For tavorite LiFeSO4F, different reaction pathways were identified by in operando XRD evaluation during charge and discharge. Furthermore, ligand involvement in the redox process was evaluated, and although most of the charge compensation was centered on the iron sites, the sulfate group also played a role in the oxidation of tavorite LiFeSO4F. In triplite LiFeSO4F and Li2FeP2O7, a redistribution of lithium and iron atoms was observed in the crystal structure during electrochemical cycling. For Li2FeP2O7, and increased randomization of metal ions occurred, which is similar to what has been reported for other iron phosphates and silicates. In contrast, triplite LiFeSO4F showed an increased ordering of lithium and iron atoms. An electrochemically induced ordering has previously not been reported upon electrochemical cycling for iron based Li-ion insertion materials, and was beneficial for the charge storage capacity of the material.

    Delarbeid
    1. Identifying the Electrochemical Processes in LiFeSO4F Cathodes for Lithium Ion Batteries
    Åpne denne publikasjonen i ny fane eller vindu >>Identifying the Electrochemical Processes in LiFeSO4F Cathodes for Lithium Ion Batteries
    Vise andre…
    2017 (engelsk)Inngår i: Chemelectrochem, Vol. 4, nr 8, s. 1896-1907Artikkel i tidsskrift (Annet vitenskapelig) 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.

    Emneord
    Batteries; conducting polymers; electrochemistry; kinetics; lithium
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-317003 (URN)10.1002/celc.201700192 (DOI)000410498700015 ()
    Forskningsfinansiär
    Swedish Foundation for Strategic Research , EM11-0028VINNOVASwedish Research Council Formas, 245-2014-668
    Tilgjengelig fra: 2017-03-08 Laget: 2017-03-08 Sist oppdatert: 2017-12-08bibliografisk kontrollert
    2. Direct Observations of Phase Distributions in Operating Lithium Ion Batteries
    Åpne denne publikasjonen i ny fane eller vindu >>Direct Observations of Phase Distributions in Operating Lithium Ion Batteries
    Vise andre…
    (engelsk)Artikkel i tidsskrift (Annet vitenskapelig) Submitted
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-317005 (URN)
    Forskningsfinansiär
    Swedish Foundation for Strategic Research , EM11-0028
    Tilgjengelig fra: 2017-03-08 Laget: 2017-03-08 Sist oppdatert: 2017-03-20
    3. Electronic Changes in LiFeSO4F-PEDOT Battery Cathodes upon Oxidation
    Åpne denne publikasjonen i ny fane eller vindu >>Electronic Changes in LiFeSO4F-PEDOT Battery Cathodes upon Oxidation
    Vise andre…
    (engelsk)Manuskript (preprint) (Annet vitenskapelig)
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-317007 (URN)
    Forskningsfinansiär
    Swedish Foundation for Strategic Research , EM11-0028
    Tilgjengelig fra: 2017-03-08 Laget: 2017-03-08 Sist oppdatert: 2017-03-20
    4. Structural and Electronic Changes in Li2FeP2O7 during Electrochemical Cycling
    Åpne denne publikasjonen i ny fane eller vindu >>Structural and Electronic Changes in Li2FeP2O7 during Electrochemical Cycling
    Vise andre…
    2015 (engelsk)Inngår i: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 27, nr 11, s. 3801-3804Artikkel i tidsskrift (Fagfellevurdert) Published
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-258346 (URN)10.1021/acs.chemmater.5b00440 (DOI)000356202800004 ()
    Tilgjengelig fra: 2015-07-13 Laget: 2015-07-13 Sist oppdatert: 2017-12-04bibliografisk kontrollert
    5. Surface Coating and Structural Changes in Triplite LiFeSO4F Cathodes
    Åpne denne publikasjonen i ny fane eller vindu >>Surface Coating and Structural Changes in Triplite LiFeSO4F Cathodes
    Vise andre…
    (engelsk)Manuskript (preprint) (Annet vitenskapelig)
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-317008 (URN)
    Forskningsfinansiär
    Swedish Foundation for Strategic Research , EM11-0028
    Tilgjengelig fra: 2017-03-08 Laget: 2017-03-08 Sist oppdatert: 2017-03-08
  • 3.
    Blidberg, Andreas
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Gustafsson, Torbjörn
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Tengstedt, Carl
    Scania CV AB, Södertälje, Sweden.
    Björefors, Fredrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Brant, William R.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Monitoring LixFeSO4F (x = 1, 0.5, 0) Phase Distributions in Operando To Determine Reaction Homogeneity in Porous Battery Electrodes2017Inngår i: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 29, nr 17, s. 7159-7169Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 4.
    Blidberg, Andreas
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Häggström, Lennart
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialfysik.
    Ericsson, Tore
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialfysik.
    Tengstedt, Carl
    Gustafsson, Torbjorn
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Björefors, Fredrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Structural and Electronic Changes in Li2FeP2O7 during Electrochemical Cycling2015Inngår i: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 27, nr 11, s. 3801-3804Artikkel i tidsskrift (Fagfellevurdert)
  • 5.
    Blidberg, Andreas
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi. Uppsala universitet.
    Sobkowiak, Adam
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Tengstedt, Carl
    Scania CV AB.
    Valvo, Mario
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Gustafsson, Torbjörn
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Björefors, Fredrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Battery Performance of PEDOT Coated LiFeSO4F Cathodes with Controlled PorosityManuskript (preprint) (Annet vitenskapelig)
  • 6.
    Blidberg, Andreas
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Sobkowiak, Adam
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Tengstedt, Carl
    Scania CV AB, Södertälje.
    Valvo, Mario
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Gustafsson, Torbjörn
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Björefors, Fredrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Identifying the Electrochemical Processes in LiFeSO4F Cathodes for Lithium Ion Batteries2017Inngår i: Chemelectrochem, Vol. 4, nr 8, s. 1896-1907Artikkel i tidsskrift (Annet vitenskapelig)
    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.

  • 7.
    Blidberg, Andreas
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Valvo, Mario
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Alfredsson, Maria
    Univ Kent, Sch Phys Sci, Canterbury CT2 7NH, Kent, England.
    Tengstedt, Carl
    Scania CV AB, SE-15187 Sodertalje, Sweden.
    Gustafsson, Torbjörn
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Björefors, Fredrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Electronic changes in poly(3,4-ethylenedioxythiophene)-coated LiFeSO4F during electrochemical lithium extraction2019Inngår i: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 418, s. 84-89Artikkel i tidsskrift (Fagfellevurdert)
    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.

1 - 7 of 7
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