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Edström, Kristina, ProfessorORCID iD iconorcid.org/0000-0003-4440-2952
Publications (10 of 308) Show all publications
Kotronia, A., Asfaw, H. D., Tai, C.-W., Edström, K. & Brandell, D. (2020). Catalytically graphitized freestanding carbon foams for 3D Li-ion microbatteries. Journal of Power Sources Advances, 1, 100002
Open this publication in new window or tab >>Catalytically graphitized freestanding carbon foams for 3D Li-ion microbatteries
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2020 (English)In: Journal of Power Sources Advances, ISSN 2666-2485, Vol. 1, p. 100002-Article in journal (Refereed) Published
Abstract [en]

A long-range graphitic ordering in carbon anodes is desirable since it facilitates Li+ transport within the structure and minimizes irreversible capacity loss. This is of vital concern in porous carbon electrodes that exhibit high surface areas and porosity, and are used in 3D microbatteries. To date, it remains a challenge to graphitize carbon structures with extensive microporosity, since the two properties are considered to be mutually exclusive. In this article, carbon foams with enhanced graphitic ordering are successfully synthesized, while maintaining their bicontinuous porous microstructures. The carbon foams are synthesized from high internal phase emulsion-templated polymers, carbonized at 1000 °C and subsequently graphitized at 2200 °C. The key to enhancing the graphitization of the bespoke carbon foams is the incorporation of Ca- and Mg-based salts at early stages in the synthesis. The carbon foams graphitized in the presence of these salts exhibit higher gravimetric capacities when cycled at a specific current of 10 mA g−1 (140 mAh g−1) compared to a reference foam (105 mAh g−1), which amounts to 33% increase.

Keywords
Emulsion, Polymer, Carbon, Graphitic foam, Three-dimensional, Li-ion battery
National Category
Materials Chemistry
Research subject
Chemistry with specialization in Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-404646 (URN)10.1016/j.powera.2020.100002 (DOI)
Funder
Swedish Energy Agency, 2015-009549StandUp
Available from: 2020-02-25 Created: 2020-02-25 Last updated: 2020-03-10Bibliographically approved
Nilsson, V., Kotronia, A., Lacey, M., Edström, K. & Johansson, P. (2020). Highly Concentrated LiTFSI-EC Electrolytes for Lithium Metal Batteries. ACS Applied Energy Materials, 3(1), 200-207
Open this publication in new window or tab >>Highly Concentrated LiTFSI-EC Electrolytes for Lithium Metal Batteries
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2020 (English)In: ACS Applied Energy Materials, ISSN 2574-0962, Vol. 3, no 1, p. 200-207Article in journal (Refereed) Published
Abstract [en]

Concentrated electrolytes have the potential to increase the stability for batteries with lithium metal anodes. In this study, liquid electrolytes were created by mixing ethylene carbonate (EC), a solid at room temperature, with a high concentration of LiTFSI salt. The binary LiTFSI–EC highly concentrated electrolytes have the benefit of extremely low volatility as compared to conventional organic electrolytes and also allow for cycling vs Li metal anodes. Using a LiTFSI–EC electrolyte with molar ratio 1:6, the Coulombic efficiency for Li plating/stripping on Cu is 97% at a current density of 1 mA cm–2 with a 2 mAh cm–2 capacity, pointing to a practically useful performance. In a full cell setup using a commercial LiFePO4 (LFP) cathode, the efficiency is maintained, proving compatibility. In comparison to other carbonate-based electrolytes, there is less accumulation of decomposition products on the surface of a cycled Li film, which in part explains the improved cycle life. In all, this electrolyte system shows promise in terms of electrochemical stability and may allow for safe Li metal batteries due to the inherent physical stability.

National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-406478 (URN)10.1021/acsaem.9b01203 (DOI)000510104700026 ()
Funder
Swedish Energy Agency, 39042-1StandUp
Available from: 2020-03-09 Created: 2020-03-09 Last updated: 2020-03-23Bibliographically approved
Menon, A. S., Ojwang, D. O., Willhammar, T., Peterson, V. K., Edström, K., Gómez, C. P. & Brant, W. (2020). Influence of Synthesis Routes on the Crystallography, Morphology, and Electrochemistry of Li2MnO3. ACS Applied Materials and Interfaces, 12(5), 5939-5950
Open this publication in new window or tab >>Influence of Synthesis Routes on the Crystallography, Morphology, and Electrochemistry of Li2MnO3
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2020 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 12, no 5, p. 5939-5950Article in journal (Refereed) Published
Abstract [en]

With the potential of delivering reversible capacities of up to 300 mAh/g, Li-rich transition-metal oxides hold great promise as cathode materials for future Li-ion batteries. However, a cohesive synthesis-structure-electrochemistry relationship is still lacking for these materials, which impedes progress in the field. This work investigates how and why different synthesis routes, specifically solid-state and modified Pechini sol-gel methods, affect the properties of Li2MnO3, a compositionally simple member of this material system. Through a comprehensive investigation of the synthesis mechanism along with crystallographic, morphological, and electrochemical characterization, the effects of different synthesis routes were found to predominantly influence the degree of stacking faults and particle morphology. That is, the modified Pechini method produced isotropic spherical particles with approximately 57% faulting and the solid-state samples possessed heterogeneous morphology with approximately 43% faulting probability. Inevitably, these differences lead to variations in electrochemical performance. This study accentuates the importance of understanding how synthesis affects the electrochemistry of these materials, which is critical considering the crystallographic and electrochemical complexities of the class of materials more generally. The methodology employed here is extendable to studying synthesis-property relationships of other compositionally complex Li-rich layered oxide systems.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2020
Keywords
Li-rich layered oxides, synthesis-property relationship, Li2MnO3, stacking faults, cathode materials
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-407140 (URN)10.1021/acsami.9b20754 (DOI)000512216900075 ()31913594 (PubMedID)
Funder
Swedish Foundation for Strategic Research StandUpSwedish Energy AgencySwedish Research Council, 349-2014-3946
Available from: 2020-03-19 Created: 2020-03-19 Last updated: 2020-03-19Bibliographically approved
Hakim, C., Sabi, N., Ma, L. A., Dahbi, M., Brandell, D., Edström, K., . . . Younesi, R. (2020). Understanding the redox process upon electrochemical cycling of the P2-Na0.78Co1/2Mn1/3Ni1/6O2 electrode material for sodium-ion batteries. COMMUNICATIONS CHEMISTRY, 3, Article ID 9.
Open this publication in new window or tab >>Understanding the redox process upon electrochemical cycling of the P2-Na0.78Co1/2Mn1/3Ni1/6O2 electrode material for sodium-ion batteries
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2020 (English)In: COMMUNICATIONS CHEMISTRY, ISSN 2399-3669, Vol. 3, article id 9Article in journal (Refereed) Published
Abstract [en]

The inclusion of nickel and manganese in layered sodium metal oxide cathodes for sodium ion batteries is known to improve stability, but the redox behaviour at high voltage is poorly understood. Here in situ X-ray spectroscopy studies show that the redox behaviour of oxygen anions can account for an increase in specific capacity at high voltages. Rechargeable sodium-ion batteries have recently attracted renewed interest as an alternative to Li-ion batteries for electric energy storage applications, because of the low cost and wide availability of sodium resources. Thus, the electrochemical energy storage community has been devoting increased attention to designing new cathode materials for sodium-ion batteries. Here we investigate P2- Na0.78Co1/2Mn1/3Ni1/6O2 as a cathode material for sodium ion batteries. The main focus is to understand the mechanism of the electrochemical performance of this material, especially differences observed in redox reactions at high potentials. Between 4.2 V and 4.5 V, the material delivers a reversible capacity which is studied in detail using advanced analytical techniques. In situ X-ray diffraction reveals the reversibility of the P2-type structure of the material. Combined soft X-ray absorption spectroscopy and resonant inelastic X-ray scattering demonstrates that Na deintercalation at high voltages is charge compensated by formation of localized electron holes on oxygen atoms.

Place, publisher, year, edition, pages
NATURE PUBLISHING GROUP, 2020
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-406713 (URN)10.1038/s42004-020-0257-6 (DOI)000511399600001 ()
Funder
Swedish Research Council, 2017-05466StandUp
Available from: 2020-03-13 Created: 2020-03-13 Last updated: 2020-03-13Bibliographically 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
Lv, F., Wang, Z., Shi, L., Zhu, J.-F., Edström, K., Mindemark, J. & Yuan, S. (2019). Challenges and development of composite solid-state electrolytes for high-performance lithium ion batteries. Journal of Power Sources, 441, Article ID 227175.
Open this publication in new window or tab >>Challenges and development of composite solid-state electrolytes for high-performance lithium ion batteries
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2019 (English)In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 441, article id 227175Article, review/survey (Refereed) Published
Abstract [en]

The safety concerns and the pursuit of high energy density have stimulated the development of high-performance solid-state lithium ion batteries. Therefore, the key component in solid-state lithium batteries, i.e. the solid-state electrolytes, also has attracted tremendous attention due to its non-flammability and good adaptability to high-voltage cathodes/lithium metal anodes. An in-depth understanding of the existing problems of solid-state electrolytes and proposed strategies for addressing these problems is crucial for the efficient design of high-performance solid-state electrolytes. In this review, we systematically summarized the current limitations of composite solid-state electrolytes and efforts to overcome them, and gave some proposals for the future perspectives of solid-state electrolytes with the aim to provide practical guidance for the researchers in this area.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Composite solid-state electrolytes, Li+ ion transportation, Interface issues, Lithium ion batteries
National Category
Materials Chemistry Energy Engineering
Identifiers
urn:nbn:se:uu:diva-397936 (URN)10.1016/j.jpowsour.2019.227175 (DOI)000494885800014 ()
Funder
Swedish Research Council
Available from: 2019-12-05 Created: 2019-12-05 Last updated: 2019-12-05Bibliographically approved
Pellegrini, V., Bodoardo, S., Brandell, D. & Edström, K. (2019). Challenges and perspectives for new material solutions in batteries. Solid State Communications, 303-304, Article ID 113733.
Open this publication in new window or tab >>Challenges and perspectives for new material solutions in batteries
2019 (English)In: Solid State Communications, ISSN 0038-1098, E-ISSN 1879-2766, Vol. 303-304, article id 113733Article in journal, Editorial material (Other academic) Published
Abstract [en]

We outline main challenges for future research in batteries, particularly, addressing the urgent needs of developing new environmentally-friendly material solutions to enhance the energy density and safety of these storage devices. This will require embracing a multidisciplinary approach encompassing traditional electro-chemistry and experimental solid-state physics, multiscale computational modelling, materials synthesis, and advanced characterization and testing.

Place, publisher, year, edition, pages
PERGAMON-ELSEVIER SCIENCE LTD, 2019
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-402956 (URN)10.1016/j.ssc.2019.113733 (DOI)000504048600001 ()
Funder
EU, Horizon 2020, 785219
Available from: 2020-01-22 Created: 2020-01-22 Last updated: 2020-01-22Bibliographically 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: 2020-02-24Bibliographically approved
Naylor, A. J., Makkos, E., Maibach, J., Guerrini, N., Sobkowiak, A., Björklund, E., . . . Bruce, P. G. (2019). Depth-dependent oxygen redox activity in lithium-rich layered oxide cathodes. Journal of Materials Chemistry A, 7(44), 25355-25368
Open this publication in new window or tab >>Depth-dependent oxygen redox activity in lithium-rich layered oxide cathodes
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2019 (English)In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 7, no 44, p. 25355-25368Article in journal (Refereed) Published
Abstract [en]

Lithium-rich materials, such as Li1.2Ni0.2Mn0.6O2, exhibit capacities not limited by transition metal redox, through the reversible oxidation of oxide anions. Here we offer detailed insight into the degree of oxygen redox as a function of depth within the material as it is charged and cycled. Energy-tuned photoelectron spectroscopy is used as a powerful, yet highly sensitive technique to probe electronic states of oxygen and transition metals from the top few nanometers at the near-surface through to the bulk of the particles. Two discrete oxygen species are identified, On− and O2−, where n < 2, confirming our previous model that oxidation generates localised hole states on O upon charging. This is in contrast to the oxygen redox inactive high voltage spinel LiNi0.5Mn1.5O4, for which no On− species is detected. The depth profile results demonstrate a concentration gradient exists for On− from the surface through to the bulk, indicating a preferential surface oxidation of the layered oxide particles. This is highly consistent with the already well-established core–shell model for such materials. Ab initio calculations reaffirm the electronic structure differences observed experimentally between the surface and bulk, while modelling of delithiated structures shows good agreement between experimental and calculated binding energies for On−.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2019
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-399616 (URN)10.1039/C9TA09019C (DOI)000498556500014 ()
Available from: 2019-12-13 Created: 2019-12-13 Last updated: 2019-12-18Bibliographically approved
Pan, R., Sun, R., Wang, Z., Lindh, J., Edström, K., Strömme, M. & Nyholm, L. (2019). Double-sided conductive separators for lithium-metal batteries. Energy Storage Materials, 21, 464-473
Open this publication in new window or tab >>Double-sided conductive separators for lithium-metal batteries
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2019 (English)In: Energy Storage Materials, ISSN 2405-8297, Vol. 21, p. 464-473Article in journal (Refereed) Published
Abstract [en]

A novel double-sided conductive (DSC) separator consisting of two 5 μm-thick carbon nanotube (CNT)/cellulose nanofiber (CNF) composite layers coated on each side of a 20 μm-thick glass-fiber (GF)/CNF composite membrane is described. In a lithium-metal battery (LMB), the DSC separator exhibits a high ionic conductivity (i.e. 1.7 mS cm−1 using an LP40 electrolyte) due to the high porosity (i.e. 66%) of the GF/CNF membrane. More stable Li anodes can also be realized by depositing Li within the porous electronically conducting CNT/CNF matrix at the DSC separator anode side due to the decreased current density. The CNT/CNF layer of the DSC separator facing the cathode, which is in direct electric contact with the current collector, decreases the overpotential for the cathode and consequently improves its capacity and rate performance significantly. A Li/Li cell containing a DSC separator showed an improved cycling stability compared to an analogous cell equipped with a commercial Celgard separator at current densities up to 5 mA cm−2 for Li deposition and stripping capacities up to 5 mAh cm−2. A proof-of-concept LMB containing a lithium iron phosphate (LFP) composite cathode and a DSC separator showed a significantly improved rate capability, yielding capacities of about 110 mAh g−1 at 5 C and 80 mAh g−1 at 10 C. The LMB cell containing a DSC separator also exhibited a capacity retention of 80% after 200 cycles at a rate of 6 C indicating that the two-sided conductive separator design has significant potential in facilitating the development of well-functioning LMBs.

Place, publisher, year, edition, pages
Elsevier, 2019
National Category
Nano Technology
Research subject
Engineering Science with specialization in Nanotechnology and Functional Materials; Engineering Science with specialization in Nanotechnology and Functional Materials
Identifiers
urn:nbn:se:uu:diva-389860 (URN)10.1016/j.ensm.2019.06.025 (DOI)000484341600043 ()
Funder
Swedish Energy Agency
Available from: 2019-07-30 Created: 2019-07-30 Last updated: 2019-10-21Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-4440-2952

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