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Edström, Kristina, ProfessorORCID iD iconorcid.org/0000-0003-4440-2952
Publications (10 of 258) Show all publications
Wang, Z., Pan, R., Ruan, C., Edström, K., Strømme, M. & Nyholm, L. (2018). Conducting polymer paper-derived separators for lithium metal batteries. Energy Storage Materials, 13, 283-292
Open this publication in new window or tab >>Conducting polymer paper-derived separators for lithium metal batteries
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2018 (English)In: Energy Storage Materials, Vol. 13, p. 283-292Article in journal (Refereed) Published
Abstract [en]

Overoxidised polypyrrole (PPy) paper has been employed as a mesoporous separator for lithium metal batteries (LMBs) based on its narrow pore size distribution, good thermal stability, high ionic conductivity (1.1 mS cm−1 with a LP40 electrolyte) and high electrolyte wettability. The overoxidised PPy paper was produced from a PPy/cellulose composite using a combined base and heat-treatment process, yielding a highly interrupted pyrrole molecular structure including N-containing polar groups maintaining the readily adaptable mesoporous structure of the pristine PPy paper. This well-defined pore structure gave rise to a homogeneous current distribution which significantly increased the performance of a LiFePO4|Li cell. With the overoxidised PPy separator, a symmetric Li|Li cell could be cycled reversibly for more than 600 h without any short-circuits in a LP40 electrolyte. This approach facilitates the manufacturing of well-defined separators for fundamental investigations of the influence of the separator structure on the performance of LMBs.

Keywords
Conducting polymers, nanocellulose, separator, porosity, lithium metal, batteries
National Category
Inorganic Chemistry Engineering and Technology
Research subject
Chemistry with specialization in Inorganic Chemistry; Chemistry with specialization in Materials Chemistry; Engineering Science with specialization in Nanotechnology and Functional Materials
Identifiers
urn:nbn:se:uu:diva-355543 (URN)10.1016/j.ensm.2018.02.006 (DOI)
Funder
Swedish Energy Agency, TriLiSwedish Foundation for Strategic Research , RMA-110012
Available from: 2018-07-01 Created: 2018-07-01 Last updated: 2018-07-04
Nilsson, V., Younesi, R., Brandell, D., Edström, K. & Johansson, P. (2018). Critical evaluation of the stability of highly concentrated LiTFSI - Acetonitrile electrolytes vs. graphite, lithium metal and LiFePO4 electrodes. Journal of Power Sources, 384, 334-341
Open this publication in new window or tab >>Critical evaluation of the stability of highly concentrated LiTFSI - Acetonitrile electrolytes vs. graphite, lithium metal and LiFePO4 electrodes
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2018 (English)In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 384, p. 334-341Article in journal (Refereed) Published
Abstract [en]

Highly concentrated LiTFSI - acetonitrile electrolytes have recently been shown to stabilize graphite electrodes in lithium-ion batteries (LIBs) much better than comparable more dilute systems. Here we revisit this system in order to optimise the salt concentration vs. both graphite and lithium metal electrodes with respect to electrochemical stability. However, we observe an instability regardless of concentration, making lithium metal unsuitable as a counter electrode, and this also affects evaluation of e.g. graphite electrodes. While the highly concentrated electrolytes have much improved electrochemical stabilities, their reductive decomposition below ca. 1.2 V vs. Li+/Li° still makes them less practical vs. graphite electrodes, and the oxidative reaction with Al at ca. 4.1 V vs. Li+/Li° makes them problematic for high voltage LIB cells. The former originates in an insufficiently stable solid electrolyte interphase (SEI) dissolving and continuously reforming – causing self-discharge, as observed by paused galvanostatic cycling, while the latter is likely caused by aluminium current collector corrosion. Yet, we show that medium voltage LiFePO4 positive electrodes can successfully be used as counter and reference electrodes.

Keywords
Highly concentrated electrolyte, Li-ion battery, SEI, Al corrosion, Self-discharge
National Category
Materials Chemistry
Research subject
Chemistry with specialization in Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-351302 (URN)10.1016/j.jpowsour.2018.03.019 (DOI)000430897700041 ()
Funder
Swedish Energy Agency, 39042-1
Available from: 2018-05-23 Created: 2018-05-23 Last updated: 2018-06-26Bibliographically approved
Björklund, E., Wikner, E., Younesi, R., Brandell, D. & Edström, K. (2018). Influence of state-of-charge in commercial LiNi0.33Mn0.33Co0.33O2/LiMn2O4-graphite cells analyzed by synchrotron-based photoelectron spectroscopy. Journal of Energy Storage, 15, 172-180
Open this publication in new window or tab >>Influence of state-of-charge in commercial LiNi0.33Mn0.33Co0.33O2/LiMn2O4-graphite cells analyzed by synchrotron-based photoelectron spectroscopy
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2018 (English)In: Journal of Energy Storage, ISSN 2352-152X, Vol. 15, p. 172-180Article in journal (Refereed) Published
Abstract [en]

Degradation mechanisms in 26 Ah commercial Li-ion battery cells comprising graphite as the negative electrode and mixed metal oxide of LiMn2O4 (LMO) and LiNi1/3Mn1/3Co1/3O2 (NMC) as the positive electrode are here investigated utilising extensive cycling at two different state-of-charge (SOC) ranges, 10–20% and 60–70%, as well as post-mortem analysis. To better analyze these mechanisms electrochemically, the cells were after long-term cycling reassembled into laboratory scale “half-cells” using lithium metal as the negative electrode, and thereafter cycled at different rates corresponding to 0.025 mA/cm2 and 0.754 mA/cm2. The electrodes were also analyzed by synchrotron-based hard x-ray photoelectron spectroscopy (HAXPES) using two different excitation energies to determine the chemical composition of the interfacial layers formed at different depth on the respective electrodes. It was found from the extensive cycling that the cycle life was shorter for the cell cycled in the higher SOC range, 60–70%, which is correlated to findings of an increased cell resistance and thickness of the SEI layer in the graphite electrode as well as manganese dissolution from the positive electrode.

Keywords
Li-ion battery, Commercial cells, Battery ageing, Photoelectron spectroscopy
National Category
Chemical Sciences
Identifiers
urn:nbn:se:uu:diva-338184 (URN)10.1016/j.est.2017.11.010 (DOI)000426619500015 ()
Available from: 2018-01-08 Created: 2018-01-08 Last updated: 2018-05-16Bibliographically approved
Rehnlund, D., Pettersson, J., Edström, K. & Nyholm, L. (2018). Lithium trapping in microbatteries based on lithium- and Cu2O-coated copper nanorods. ChemistrySelect, 3(8), 2311-2314
Open this publication in new window or tab >>Lithium trapping in microbatteries based on lithium- and Cu2O-coated copper nanorods
2018 (English)In: ChemistrySelect, E-ISSN 2365-6549, Vol. 3, no 8, p. 2311-2314Article in journal (Refereed) Published
Abstract [en]

Microbatteries based on three-dimensional (3D) electrodes composed of thin films of Li and Cu2O coated on Cu nanorod current collectors by electrodeposition and spontaneous oxidation, respectively, are described and characterised electrochemically. High-resolution scanning electron microscopy (HR-SEM) data indicate that the Li electrodeposition resulted in a homogenous coverage of the Cu nanorods and elemental analyses were also used to determine the amount of lithium in the Li-coated electrodes. The results show that 3D Cu2O/Cu electrodes can be cycled versus 3D Li/Cu electrodes but that the capacity decreased during the cycling due to Li trapping in the Cu current collector of the 3D Li/Cu electrode. These findings highlight the problem of using copper current collectors together with metallic lithium as the formation of a solid solution yields considerable losses of electroactive lithium and hence capacity.

Keywords
lithium trapping, microbatteries, nanorods, Cu2O, copper
National Category
Inorganic Chemistry
Research subject
Chemistry with specialization in Inorganic Chemistry
Identifiers
urn:nbn:se:uu:diva-343590 (URN)10.1002/slct.201800281 (DOI)000426495600015 ()
Funder
Swedish Research Council, 2012-4681, 2015-04421StandUpSwedish Energy Agency
Available from: 2018-02-28 Created: 2018-02-28 Last updated: 2018-05-31Bibliographically approved
Renman, V., Valvo, M., Tai, C.-W., Gómez, C. P., Edström, K. & Liivat, A. (2018). Manganese pyrosilicates as novel positive electrode materials for Na-ion batteries. SUSTAINABLE ENERGY & FUELS, 2(5), 941-945
Open this publication in new window or tab >>Manganese pyrosilicates as novel positive electrode materials for Na-ion batteries
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2018 (English)In: SUSTAINABLE ENERGY & FUELS, ISSN 2398-4902, Vol. 2, no 5, p. 941-945Article in journal (Refereed) Published
Abstract [en]

A carbon-coated pyrosilicate, Na2Mn2Si2O7/C, was synthesized and characterized for use as a new positive-electrode material for sodium ion batteries. The material consists of 20–80 nm primary particles embedded in a ≈10 nm-thick conductive carbon matrix. Reversible insertion of Na+ ions is clearly demonstrated with ≈25% of its theoretical capacity (165 mA h g−1) being accessible at room temperature at a low cycling rate. The material yields an average potential of 3.3 V vs. Na+/Na on charge and 2.2 V on discharge. DFT calculations predict an equilibrium potential for Na2Mn2Si2O7 in the range of 2.8–3.0 V vs. Na+/Na, with a possibility of a complete flip in the connectivity of neighboring Mn-polyhedra – from edge-sharing to disconnected and vice versa. This significant rearrangement in Mn coordination (≈2 Å) and large volume contraction (>10%) could explain our inability to fully desodiate the material, and illustrates well the need for a new electrode design strategy beyond the conventional “down-sizing/coating” procedure.

National Category
Inorganic Chemistry Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-356076 (URN)10.1039/c7se00587c (DOI)000431422700003 ()
Funder
Swedish Research Council, 2011-6512Swedish Research Council, 2010-4824Swedish Research Council Formas, 245-2014-668Knut and Alice Wallenberg FoundationStandUp
Available from: 2018-07-13 Created: 2018-07-13 Last updated: 2018-07-13Bibliographically approved
Pan, R., Xu, X., Sun, R., Wang, Z., Lindh, J., Edström, K., . . . Nyholm, L. (2018). Nanocellulose Modified Polyethylene Separators for Lithium Metal Batteries. Small, 1-9, Article ID 1704371.
Open this publication in new window or tab >>Nanocellulose Modified Polyethylene Separators for Lithium Metal Batteries
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2018 (English)In: Small, p. 1-9, article id 1704371Article in journal (Refereed) Published
Abstract [en]

Abstract Poor cycling stability and safety concerns regarding lithium (Li) metal anodes are two major issues preventing the commercialization of high‐energy density Li metal‐based batteries. Herein, a novel tri‐layer separator design that significantly enhances the cycling stability and safety of Li metal‐based batteries is presented. A thin, thermally stable, flexible, and hydrophilic cellulose nanofiber layer, produced using a straightforward paper‐making process, is directly laminated on each side of a plasma‐treated polyethylene (PE) separator. The 2.5 µm thick, mesoporous (≈20 nm average pore size) cellulose nanofiber layer stabilizes the Li metal anodes by generating a uniform Li+ flux toward the electrode through its homogenous nanochannels, leading to improved cycling stability. As the tri‐layer separator maintains its dimensional stability even at 200 °C when the internal PE layer is melted and blocks the ion transport through the separator, the separator also provides an effective thermal shutdown function. The present nanocellulose‐based tri‐layer separator design thus significantly facilitates the realization of high‐energy density Li metal‐based batteries.

Keywords
cellulose, current distribution, lithium dendrites, lithium metal batteries, separators
National Category
Materials Chemistry Engineering and Technology
Research subject
Engineering Science with specialization in Nanotechnology and Functional Materials
Identifiers
urn:nbn:se:uu:diva-349143 (URN)10.1002/smll.201704371 (DOI)
Available from: 2018-04-22 Created: 2018-04-22 Last updated: 2018-05-02Bibliographically approved
Doubaji, S., Ma, L., Asfaw, H. D., Izanzar, I., Xu, R., Alami, J., . . . Saadoune, I. (2018). On the P2-NaxCo1−y(Mn2/3Ni1/3)yO2 Cathode Materials for Sodium-Ion Batteries: Synthesis, Electrochemical Performance, and Redox Processes Occurring during the Electrochemical Cycling. ACS Applied Materials and Interfaces, 10(1), 488-501
Open this publication in new window or tab >>On the P2-NaxCo1−y(Mn2/3Ni1/3)yO2 Cathode Materials for Sodium-Ion Batteries: Synthesis, Electrochemical Performance, and Redox Processes Occurring during the Electrochemical Cycling
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2018 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, no 1, p. 488-501Article in journal (Refereed) Published
Abstract [en]

P2-type NaMO2sodiated layered oxides withmixed transition metals are receiving considerable attention foruse as cathodes in sodium-ion batteries. A study on solidsolution (1−y)P2-NaxCoO2−(y)P2-NaxMn2/3Ni1/3O2(y=0,1/3, 1/2, 2/3, 1) reveals that changing the composition of thetransition metals affects the resulting structure and the stabilityof pure P2 phases at various temperatures of calcination. For 0≤y≤1.0, the P2-NaxCo(1−y)Mn2y/3Niy/3O2solid-solutioncompounds deliver good electrochemical performance whencycled between 2.0 and 4.2 V versus Na+/Na with improved capacity stability in long-term cycling, especially for electrodematerials with lower Co content (y= 1/2 and 2/3), despite lower discharge capacities being observed. The (1/2)P2-NaxCoO2−(1/2)P2-NaxMn2/3Ni1/3O2composition delivers a discharge capacity of 101.04 mAh g−1with a capacity loss of only 3% after 100cycles and a Coulombic efficiency exceeding 99.2%. Cycling this material to a higher cutoffvoltage of 4.5 V versus Na+/Naincreases the specific discharge capacity to≈140 mAh g−1due to the appearance of a well-defined high-voltage plateau, but afteronly 20 cycles, capacity retention declines to 88% and Coulombic efficiency drops to around 97%. In situ X-ray absorption near-edge structure measurements conducted on composition NaxCo1/2Mn1/3Ni1/6O2(y= 1/2) in the two potential windows studiedhelp elucidate the operating potential of each transition metal redox couple. It also reveals that at the high-voltage plateau, all ofthe transition metals are stable, raising the suspicion of possible contribution of oxygen ions in the high-voltage plateau.

Keywords
Na-ion batteries, P2-type materials, energy storage, in situ XANES measurements, high-voltage plateau
National Category
Natural Sciences Inorganic Chemistry
Research subject
Chemistry with specialization in Inorganic Chemistry
Identifiers
urn:nbn:se:uu:diva-337712 (URN)10.1021/acsami.7b13472 (DOI)000422814400053 ()29098854 (PubMedID)
Funder
StandUpSwedish Research Council, 2015-05106
Available from: 2018-01-03 Created: 2018-01-03 Last updated: 2018-02-28Bibliographically approved
Wang, Z., Pan, R., Ruan, C., Edström, K., Strömme, M. & Nyholm, L. (2018). Redox-Active Separators for Lithium-Ion Batteries. ADVANCED SCIENCE, 5(3), Article ID 1700663.
Open this publication in new window or tab >>Redox-Active Separators for Lithium-Ion Batteries
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2018 (English)In: ADVANCED SCIENCE, ISSN 2198-3844, Vol. 5, no 3, article id 1700663Article in journal (Refereed) Published
Abstract [en]

A bilayered cellulose-based separator design is presented that can enhance the electrochemical performance of lithium-ion batteries (LIBs) via the inclusion of a porous redox-active layer. The proposed flexible redox-active separator consists of a mesoporous, insulating nanocellulose fiber layer that provides the necessary insulation between the electrodes and a porous, conductive, and redox-active polypyrrole-nanocellulose layer. The latter layer provides mechanical support to the nanocellulose layer and adds extra capacity to the LIBs. The redox-active separator is mechanically flexible, and no internal short circuits are observed during the operation of the LIBs, even when the redox-active layer is in direct contact with both electrodes in a symmetric lithium-lithium cell. By replacing a conventional polyethylene separator with a redox-active separator, the capacity of the proof-of-concept LIB battery containing a LiFePO4 cathode and a Li metal anode can be increased from 0.16 to 0.276 mA h due to the capacity contribution from the redox-active separator. As the presented redox-active separator concept can be used to increase the capacities of electrochemical energy storage systems, this approach may pave the way for new types of functional separators.

Place, publisher, year, edition, pages
WILEY, 2018
Keywords
capacity, cellulose, conducting polymers, lithium-ion batteries, redox-active separators
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-354519 (URN)10.1002/advs.201700663 (DOI)000428310500012 ()29593967 (PubMedID)
Funder
Swedish Foundation for Strategic Research , RMA-110012]Swedish Energy AgencyStandUpCarl Tryggers foundation
Available from: 2018-07-20 Created: 2018-07-20 Last updated: 2018-07-20Bibliographically approved
Wei, W., Valvo, M., Edström, K. & Nyholm, L. (2018). Size-dependent Electrochemical Performance of Monolithic Anatase TiO2 Nanotube Anodes for Sodium-ion Batteries. ChemElectroChem, 5(4), 674-684
Open this publication in new window or tab >>Size-dependent Electrochemical Performance of Monolithic Anatase TiO2 Nanotube Anodes for Sodium-ion Batteries
2018 (English)In: ChemElectroChem, Vol. 5, no 4, p. 674-684Article in journal (Refereed) Published
Abstract [en]

Well-defined, monolithic TiO2 nanotube thin films havebeen used as model anode electrodes to study Na-ion storage in anatase TiO2. It is shown that anatase TiO2 nanotubes with wall thicknesses up to 50 nm can be transformed into amorphous sodium titanate (e.g. Na0.2TiO2) nanotubes via an electrochemical activation process at about 0.2 V vs. Na+/Na. Due to the Na+ insertion and extraction reactions at about 0.55 and 0.75 V vs. Na+/Na, respectively, the activated TiO2 nanotubes exhibit reversible capacities of 170 mAh g-1. For the first time, it is shown that the nanotube length and wall thickness play critical roles in determining the electrochemical performances of this type of electrodes in Na-ion cells. An excellent rate performance, yielding capacities of about 33mAh g-1 at 20C and 161 mAh g-1 at C/5 rates, as well as a capacity retention of more than 97% after more than 350 cycles, could be achieved with nanotubes with a wall thickness of up to 20 nm. Thecycling rate for the nanotubes with a tube length of 4.5 μm should,however, be limited to 1C to guarantee a cycle life of about 200 cycles.

Keywords
TiO2, nanotubes, sodium, batteries, electrodes, free-standing, wall thickness, length
National Category
Inorganic Chemistry
Research subject
Chemistry with specialization in Inorganic Chemistry
Identifiers
urn:nbn:se:uu:diva-337289 (URN)10.1002/celc.201701267 (DOI)000425380200015 ()
Funder
Swedish Research Council Formas, 245- 2014-668StandUp
Available from: 2017-12-21 Created: 2017-12-21 Last updated: 2018-05-07Bibliographically approved
Sun, B., Asfaw, H. D., Rehnlund, D., Mindemark, J., Nyholm, L., Edström, K. & Brandell, D. (2018). Towards Solid-State 3D-Microbatteries using Functionalized Polycarbonate-based Polymer Electrolytes. ACS Applied Materials and Interfaces, 10(3), 2407-2413
Open this publication in new window or tab >>Towards Solid-State 3D-Microbatteries using Functionalized Polycarbonate-based Polymer Electrolytes
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2018 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, no 3, p. 2407-2413Article in journal (Refereed) Published
Abstract [en]

3D-microbatteries (3D-MBs) impose new demands for theselection, fabrication and compatibility of the different battery components, notleast the electrolytes. Herein, solid polymer electrolytes (SPEs) based on poly(trimethylene carbonate) (PTMC) have been implemented in 3D-MB systems. 3D electrodes of two different architectures, LiFePO4-coated carbon foams and Cu2O-coated Cu nanopillars, have been coated with SPEs and used in Li-cells. Functionalized PTMC with hydroxyl end groups was found to enable uniform and well-covering coatings on LiFePO4-coated carbon foams, although the cell cycling performance was limited by the large SPE resistance. By employing a SPE prepared from a copolymer of TMC and caprolactone (CL), with higher ionic conductivity, Li-cells composed of Cu2O-coated Cu nanopillars were constructed and tested both at room temperature and 60 °C. The footprint areal capacity of the cells was ca. 0.02 mAh cm-2 for an area gain factor (AF) of 2.5, and 0.2 mAh cm-2 for a relatively dense nanopillar-array (AF=25) at a current density of 0.008 mA cm-2at ambient temperature (22±1 °C). These results provide new routes towards the realization of all-solid-state 3D-MBs.

Keywords
Li-battery, 3D-microbattery, polymer electrolyte, nanopillars, carbon foam, Cu2O, Cu, nanorods
National Category
Inorganic Chemistry Materials Chemistry
Research subject
Chemistry with specialization in Organic Chemistry; Chemistry with specialization in Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-336964 (URN)10.1021/acsmi.7b13788 (DOI)000423496500027 ()29199816 (PubMedID)
Funder
StandUp
Available from: 2017-12-19 Created: 2017-12-19 Last updated: 2018-03-16Bibliographically approved
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Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-4440-2952

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