| 51411. |
- Lundin, Filippa, 1992, et al.
(författare)
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Ion Dynamics and Nanostructures of Diluted Ionic Liquid Electrolytes
- 2022
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Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 126:38, s. 16262-16271
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Tidskriftsartikel (refereegranskat)abstract
- Diluted ionic liquid electrolytes are promising candidates in next-generation batteries enabling the implementation of lithium metal anodes. The diluent should fully mix with the ionic liquid while not interacting with the Li ions to preserve the ionic liquid character, which is beneficial for Li-metal electrode stability. We report on the influence of a hydrofluoroether (HFE) diluent on ion dynamics and nanostructure of an ionic liquid electrolyte. We show that the ionic liquid and the diluent are fully miscible and that the solvation structure of the Li ions is not affected by the presence of HFE. The increase in the conductivity by the addition of the diluent is directly related to a decrease in viscosity with faster dynamics of all ionic species. However, the relative increase in mobility is considerably larger for the ionic liquid cation as a result of a preferred interaction with HFE. On the microscopic scale, more complex local non-Gaussian diffusive dynamics are found, faster than what is expected from the self-diffusion coefficient. The relative change of the dynamics with the addition of HFE on macro- and microscopic length scales correlates well, which underlines the connection between the motions probed on different length and time scales.
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| 51412. |
- Lundin, Filippa, 1992
(författare)
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Local Structure and Dynamics of Next Generation Electrolytes - linking microscopic and macroscopic properties
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The electrolyte is a crucial part of a battery in terms of performance, longevity and safety. However, the state-of-the-art electrolytes for lithium-ion batteries are based on organic solvents and Li-salts (typically at 1M concentration) which are volatile and degrade at higher temperatures. In addition, these electrolytes are not suitable for next generation battery concepts where the use of metallic lithium at the anode side is a prerequisite. Thus, there is currently a strong effort to find new electrolyte concepts to both improve safety of current battery technology and pave way for next generation batteries. In the search for new electrolytes, highly concentrated electrolytes and ionic liquids have been proposed as alternatives through properties such as high thermal stability, lower reactivity with cell components and increased electrochemical stability window. A common feature for highly concentrated electrolytes and ionic liquids is an ordering on mesoscopic length scales, normally not found in simple liquids, resulting from the correlation between the ions. This nanostructure can be expected to influence the ion transport and a key to developing these new electrolyte concepts is to understand the structure and dynamics on mesoscopic length scales and how this links to macroscopic transport. In this thesis, the microscopic properties of ionic liquids and diluted ionic liquids are investigated together with highly concentrated electrolytes based on an organic solvent. To achieve this goal X-ray and neutron scattering are invaluable tools as they allow for measurements at the time and length scale of typical molecular motions and interactions. Complementary techniques such as conductivity and viscosity measurements, differential scanning calorimetry, and Raman spectroscopy have been used in order to link between the macroscopic and microscopic properties and between local structure and dynamics.
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| 51413. |
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| 51414. |
- Lundin, Filippa, 1992, et al.
(författare)
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Pressure and Temperature Dependence of Local Structure and Dynamics in an Ionic Liquid
- 2021
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Ingår i: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-5207 .- 1520-6106. ; 125:10, s. 2719-2728
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Tidskriftsartikel (refereegranskat)abstract
- A detailed understanding of the local dynamics in ionic liquids remains an important aspect in the design of new ionic liquids as advanced functional fluids. Here, we use small-angle X-ray scattering and quasi-elastic neutron spectroscopy to investigate the local structure and dynamics in a model ionic liquid as a function of temperature and pressure, with a particular focus on state points (P,T) where the macroscopic dynamics, i.e., conductivity, is the same. Our results suggest that the initial step of ion transport is a confined diffusion process, on the nanosecond timescale, where the motion is restricted by a cage of nearest neighbors. This process is invariant considering timescale, geometry, and the participation ratio, at state points of constant conductivity, i.e., state points of isoconductivity. The connection to the nearest-neighbor structure is underlined by the invariance of the peak in the structure factor corresponding to nearest-neighbor correlations. At shorter timescales, picoseconds, two localized relaxation processes of the cation can be observed, which are not directly linked to ion transport. However, these processes also show invariance at isoconductivity. This points to that the overall energy landscape in ionic liquids responds in the same way to density changes and is mainly governed by the nearest-neighbor interactions.
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| 51415. |
- Lundin, Filippa, 1992
(författare)
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Structure and Dynamics in Ionic Liquid and Highly Concentrated Electrolytes
- 2020
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The electrolyte is a crucial part of a battery in terms of longevity and safety. However, the state-of-the-art electrolytes for lithium-ion batteries are based on organic solvents and Li-salts (typically 1M concentration) and are known to be volatile and to degrade at higher temperature. In the search for a safer electrolyte, highly concentrated electrolytes (HCEs) and ionic liquids (ILs) have been proposed as alternatives. The high salt concentration in HCEs (typically >4M) results in an increased electrochemical stability whereas ionic liquids, consisting only of ions, are known to have a negligible vapour pressure and high thermal stability. A common feature for HCEs and ILs is an ordering on mesoscopic length scales, normally not found in simple liquids, resulting from correlations between the ions. This nanostructure can be expected to influence the ion transport and a key to develop these new electrolyte concepts is to understand the structure and dynamics on the molecular level and how this links to macroscopic transport properties. The thesis focuses on the understanding of mesoscopic structure and dynamics in ILs and HCEs with the help of neutron and X-ray scattering with the aim to identify how local dynamical processes are influenced by the nanostrucutre. I have investigated an archetypal HCE system where the Li-salt LiTFSI is dissolved in acetonitrile and a model ionic liquid. Varying the Li-salt concentration in the HCE we can link the local processes to the development of the structure. The ion transport in the HCE takes place by the means of a jump diffusion and is highly dependent on the salt concentration and temperature of the system. For the ionic liquid we investigate the response of structure and dynamics to changes in both pressure and temperature with a particular focus on state points (P,T) where the macroscopic dynamics i.e. conductivity is constant. A conned diusion was found with a diusion coecient in agreement with macroscopic conductivity, thus providing a link between the microscopic and macroscopic dynamics.
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| 51416. |
- Lundin, Filippa, 1992, et al.
(författare)
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Structure and dynamics of highly concentrated LiTFSI/acetonitrile electrolytes
- 2021
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Ingår i: Physical Chemistry Chemical Physics. - : Royal Society of Chemistry (RSC). - 1463-9084 .- 1463-9076. ; 23:25, s. 13819-13826
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Tidskriftsartikel (refereegranskat)abstract
- High salt concentration has been shown to induce increased electrochemical stability in organic solvent-based electrolytes. Accompanying the change in bulk properties is a structural ordering on mesoscopic length scales and changes in the ion transport mechanism have also been suggested. Here we investigate the local structure and dynamics in highly concentrated acetonitrile electrolytes as a function of salt concentration. Already at low concentrations ordering on microscopic length scales in the electrolytes is revealed by small angle X-ray scattering, as a result of correlations of Li+ coordinating clusters. For higher salt concentrations a charge alternation-like ordering is found as anions start to take part in the solvation. Results from quasi-elastic neutron spectroscopy reveal a jump diffusion dynamical process with jump lengths virtually independent of both temperature and Li-salt concentration. The jump can be envisaged as dissociation of a solvent molecule or anion from a particular Li+ solvation structure. The residence time, 50-800 ps, between the jumps is found to be highly temperature and Li-salt concentration dependent, with shorter residence times for higher temperature and lower concentrations. The increased residence time at high Li-salt concentration can be attributed to changes in the interaction of the solvation shell as a larger fraction of TFSI anions take part in the solvation, forming more stable solvation shells.
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| 51417. |
- Lundin Frisk, Emrik, 1994
(författare)
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Geosystem services to support decisions on subsurface use
- 2023
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Awareness of the subsurface is in general low and is not a daily concern for decision-makers. This often results in that decisions on access to subsurface resources instead are guided by a ‘first come, first served principle’. This is precarious, as such decisions may lead to intra- and intergenerational conflicts of interest, as utilisation of one subsurface resource at one point in time may inhibit, or severely limit, the utilisation of other subsurface resources in the future, potentially impeding sustainable development. Though not fully developed the concept of geosystem services (GS) has been put forward as a concept that can make these resources more visible and acknowledged in decision-making. However, a systematic literature review of scientific publications on geosystem services was carried out and the emerging picture is that the geosystem services concept is both one of novelty and one of discrepancy, with two prominent definitions: A) GS are abiotic services that are the direct result of the planet’s geodiversity, independent of the interactions with biotic nature – there is no differentiation between suprasurface and subsurface features, and B) GS provide benefits specifically resulting from the subsurface. Of the identified geosystem services, 31 out of 39 are listed in the abiotic extension of CICES 5.1 (Common International Classification of Ecosystem Services), but some essential services are omitted. To support well-informed decisions on the utilisation of subsurface resources, positive effects need to be weighed against negative effects on a society-wide level, not least regarding effects on the future supply of subsurface resources, or subsurface geosystem services. Cost-benefit analysis (CBA) is a method for providing a basis for such decisions by considering the positive and negative effects on human well-being (i.e., benefits and costs, respectively) on a societal level. In this thesis, a generic CBA rule for assessing subsurface projects is applied to two theoretical cases to show conceptually how CBA can be applied for the prioritisation of competing uses of subsurface resources. The result from these two cases highlights that a systematic mapping of the effects that arise due to subsurface projects, using geosystems services as a point of departure, can make the consequences of such projects more visible and indicate who will be affected. The exemplification shows that a CBA can provide a basis for supporting decisions on prioritising competing subsurface uses, but that there is a need for complementary types of analyses to capture the wide range of benefits the subsurface provides. Finally, some supporting and possibly regulating geosystem services can be either intermediate or final services depending on analytical context, which is important to consider, not least in a CBA to avoid double counting.
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| 51418. |
- Lundin Frisk, Emrik, 1994, et al.
(författare)
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The geosystem services concept – What is it and can it support subsurface planning?
- 2022
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Ingår i: Ecosystem Services. - : Elsevier BV. - 2212-0416. ; 58
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Forskningsöversikt (refereegranskat)abstract
- The subsurface is a multifunctional natural resource. However, a mindset of “out of sight, out of mind” and a first-come-first-served principle are prevalent when accessing these resources, compromising fair intergenerational and intragenerational distribution and sustainable development. As with the ecosystem services (ES) concept, which acknowledges the contribution of the living part of nature to human well-being, the concept of geosystem services (GS) has been suggested as a way to highlight abiotic services and services provided by the subsurface. The overall aim of this study was to review current definitions of GS and their categorisation, and to suggest how the concept of GS can support subsurface planning. A systematic literature review on GS was carried out following the PRISMA protocol drawing from the Scopus database. The emerging picture from the reviewed articles is that the GS concept is both one of novelty and one currently showing inconsistency, with two prominent definitions: A) GS are abiotic services that are the direct result of the planet's geodiversity, independent of the interactions with biotic nature – there is no differentiation between suprasurface and subsurface features, and B) GS provide benefits specifically resulting from the subsurface. Thirty-one out of thirty-nine GS listed in the reviewed literature are included in the abiotic extension of the common ES framework CICES v5.1, but some essential services are omitted. A unified definition of GS is desirable to build a common framework for classifying and describing GS, potentially following the CICES structure for ES. Such a framework can support systematic inclusion of GS in planning processes and contribute to improved subsurface planning. In planning practice, there are examples of important GS that are already included under the ES umbrella because planners are aware of their importance but a comprehensive framework to handle these services is lacking.
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| 51419. |
- Lundin, Johan, 1975-, et al.
(författare)
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A new agenda for research on higher education and information technology
- 2008
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Ingår i: Proceedings of the 31th Information Systems Research Seminar in Scandinavia, IRIS 31. - Åre. ; 31
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Konferensbidrag (refereegranskat)abstract
- There is a need for a more timely agenda for research on teaching and learning, and the use information technology in higher education. It is here claimed that many of the prior research issues within this area are obsolete. Information technology infrastructure previously provided solely by the institutions of higher education is now successively replaced by the students own technology which they bring to the educational context. The new agenda should orient towards (i) integration of students own technology in educational activities, and integration between on and of campus learning activities (ii) tools for supporting activities in classrooms such as presenting, visualizing and simulating, and (iii) issues of availability to participate in alternative ways, making educational activities available to new groups. The suggested agenda is discussed using a number of anecdotes collected in various educational settings.
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| 51420. |
- Lundin, Johan, 1975, et al.
(författare)
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Collaborative learning in mobile work
- 2003
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Ingår i: Journal of Computer Assisted Learning. ; 19:3, s. 273-283
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Tidskriftsartikel (refereegranskat)
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