Change search
Refine search result
1 - 29 of 29
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Eric, Jacques
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Kjell, Maria
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Zenkert, Dan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Behm, Mårten
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Impact of the mechanical loading on the electrochemical capacity of carbon fibres for use in energy storage composite materials2011Conference paper (Other academic)
    Abstract [en]

    Reducing system mass for improvements in system performance has become a priority for future applications such as mobile phones or electric vehicles which require load bearing components and electrical energy storage devices. Structure and energy storage are usually subsystems with the highest mass contributions but energy storage components are structurally parasitic. A novel solution is a multifunctional lightweight design combining these two functions in a single material entity able to simultaneously bear mechanical loads as a carbon fiber composite component and store electrochemical energy as a lithium-ion battery.

  • 2.
    Hellqvist Kjell, Maria
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Performance of Conventional and Structural Lithium-Ion Batteries2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Lithium-ion batteries have, in recent years, experienced a rapid development from small everyday devices towards hybrid electric vehicle (HEV) applications. Due to this shift in application area, the battery performance andits degradation with time are becoming increasingly important issues to besolved.In this thesis, lithium-ion batteries are investigated with focus on lifetime performance of an existing battery chemistry, and development of electrodes for so-called structural batteries. The systems are evaluated by electrochemical methods, such as cycling and electrochemical impedance spectroscopy (EIS),combined with material characterization and modeling.

    Lifetime performance of mesocarbon microbeads (MCMB)/LiFePO4 cells was investigated to develop an understanding of how this technology tolerates and is influenced by different conditions, such as cycling, storage and temperature.The lifetime of the LiFePO4-based cells was found to be significantly reduced by cycling at elevated temperature, almost five times shorter compared to cycle-aged cells at ambient temperature. The calendar-aged cells also showed major signs of degradation at elevated temperatures. The overall cause of aging was electrolyte decomposition which resulted in loss of cyclable lithium, i.e. capacity fade, and impedance increase.

    Commercially available polyacrylonitrile (PAN)-based carbon fibers were investigated, both electrochemically and mechanically, to determine their suitability as negative electrodes in structural batteries. The electrochemical performance of carbon fibers was found to be excellent compared to other negative electrode materials, especially for single or well-separated fibers. The mechanical properties, measured as changes in the tensile properties, showed that the tensile stiffness was unaffected by lithium-ion intercalation and cycling. The ultimate tensile strength, however, showed a distinct variation with state-of-charge (SOC). Overall, carbon fibers are suitable for structural battery applications.

  • 3.
    Hellqvist Kjell, Maria
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Jacques, Eric
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Zenkert, Dan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Behm, Mårten
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    PAN-based carbon fiber negative electrodes for structural lithium-ion batteries2011In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 158, no 12, p. A1455-A1460Article in journal (Refereed)
    Abstract [en]

    Several grades of commercially-available polyacrylonitrile (PAN)-based carbon fibers have been studied for structural lithium-ion batteries to understand how the sizing, different lithiation rates and number of fibers per tow affect the available reversible capacity, when used as both current collector and electrode, for use in structural batteries. The study shows that at moderate lithiation rates, 100 mA g-1, most of the carbon fibers display a reversible capacity close to or above 100 mAh g-1 after ten full cycles. For most of the fibers, removing the sizing increased the capacity to some extent. However, the main factor affecting the measured capacity was the lithiation rate. Decreasing the current by a tenth yielded an increase of capacity of around 100 for all the tested grades. From the measurements performed in this study it is evident that carbon fibers can be used as the active negative material and current collector in structural batteries. © 2011 The Electrochemical Society.

  • 4.
    Hellqvist Kjell, Maria
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Jacques, Eric
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Zenkert, Dan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Behm, Mårten
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    PAN-based carbon fibers for structural lithium-ion batteries2012In: ECCM 2012 - Composites at Venice, Proceedings of the 15th European Conference on Composite Materials, European Conference on Composite Materials, ECCM , 2012Conference paper (Refereed)
    Abstract [en]

    Structural batteries have the potential to become an integrated part of the device, functioning as both a structural element and as energy storage by combining electrochemical properties and mechanical properties in the same material. In addition, an increase of power and energy density on a system level could be achieved. The electrochemical properties of seven different commercially available PAN-based carbon fibers have been investigated as negative electrodes for structural lithium-ion batteries. All of the tested fibers showed some ability to intercalate lithium ions. The performance varied significantly between the different grades of fiber. Fibers with intermediate modulus showed the most promising results.

  • 5.
    Hellqvist Kjell, Maria
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Malmgren, Sara
    Ciosek, Katarzyna
    Behm, Mårten
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Edström, Kristina
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Comparing aging of graphite/LiFePO4 cells at 22 degrees C and 55 degrees C - Electrochemical and photoelectron spectroscopy studies2013In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 243, p. 290-298Article in journal (Refereed)
    Abstract [en]

    Accelerated aging at elevated temperature is commonly used to test lithium-ion battery lifetime, but the effect of an elevated temperature is still not well understood. If aging at elevated temperature would only be faster, but in all other respects equivalent to aging at ambient temperature, cells aged to end-of-life (EOL) at different temperatures would be very similar. The present study compares graphite/LiFePO4-based cells either cycle- or calendar-aged to EOL at 22 degrees C and 55 degrees C. Cells cycled at the two temperatures show differences in electrochemical impedance spectra as well as in X-ray photoelectron spectroscopy (XPS) spectra. These results show that lithium-ion cell aging is a complex set of processes. At elevated temperature, the aging is accelerated in process-specific ways. Furthermore, the XPS results of cycle-aged samples indicate increased deposition of oxygenated LiPF6 decomposition products in both the negative and positive electrode/electrolyte interfaces. The decomposition seems more pronounced at elevated temperature, and largely accelerated by cycling, which could contribute to the observed cell impedance increase.

  • 6.
    Hellqvist Kjell, Maria
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Zavalis, Tommy
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Behm, Mårten
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Electrochemical characterization of lithium intercalation processes of PAN-based carbon fibers in a microelectrode system2013In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 160, no 9, p. A1473-A1481Article in journal (Refereed)
    Abstract [en]

    A full electrochemical investigation of the lithium intercalation processes in a commercially available PAN-based carbon fiber, Toho Tenax IMS65 (unsized and sized) primarily intended to be used in structural lithium-ion batteries, has been performed. In order to extract the electrochemical properties, a specially designed microelectrode system consisting of a single fiber working electrode, lithium-foil counter electrode and well-characterized battery materials were utilized. The properties, for 5 to 100% state-of-charge (SOC), were mainly determined from electrochemical impedance spectroscopy (EIS) measurements by fitting of a physics-based model, and electronic conductivity examination. The study shows excellent mass transport and kinetic properties, especially at high SOCs for this specific carbon fiber compared to other negative electrode materials. Some electrochemical parameters vary depending on sizing, but are too small to affect the actual electrochemical performance. A strong SOC dependence is shown for most electrochemical properties, including the electronic conductivity.

  • 7.
    Hellqvist Kjell, Maria
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Zavalis, Tommy Georgios
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Behm, Mårten
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Characterization of Lithium Intercalation Processes of PAN-based Carbon Fibers in a Microelectrode SystemArticle in journal (Other academic)
  • 8.
    Jacques, Eric
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Hellqvist Kjell, Maria
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Zenkert, Dan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Behm, Mårten
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Effect of lithium-ion intercalation on the tensile properties of carbon fibres for energy storage composites2012In: ECCM 2012 - Composites at Venice, Proceedings of the 15th European Conference on Composite Materials, European Conference on Composite Materials, ECCM , 2012Conference paper (Refereed)
    Abstract [en]

    Carbon fibres can be used as structural electrodes because they have a high tensile properties-to-weight ratio and a graphitic structure which enables lithium-ion intercalation. Carbon fibre specimens were used as electrodes in laboratory cells. It was found that the fibre undergoes an ultimate tensile strength drop and an axial expansion which depend on the measured capacity. The results suggest that a tensile strain develops in the carbon fibre which is pre-stressed in tension and that this pre-stress correlates with the amount of lithiumions intercalated.

  • 9.
    Jacques, Eric
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Hellqvist Kjell, Maria
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Zenkert, Dan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Lithium-intercalated Carbon Fibers as Piezo-electrochemical Transducer for Energy HarvestingManuscript (preprint) (Other academic)
  • 10.
    Jacques, Eric
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Hellqvist Kjell, Maria
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Zenkert, Dan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Piezo-electrochemical effect in lithium-intercalated carbon fibres2013In: Electrochemistry communications, ISSN 1388-2481, E-ISSN 1873-1902, Vol. 35, p. 65-67Article in journal (Refereed)
    Abstract [en]

    In this paper we have conducted experiments to investigate the coupling between electrochemical and mechanical properties of lithium (Li)-intercalating carbon fibres (CFs). The results show promising potential for new functionalities of CFs for electrochemical actuation, sensing and energy harvesting. Li-intercalation at 1 C-rate in CFs subjected to a constant tensile extension induced a free reversible longitudinal expansion strain of approximately 0.30% which can be used as mechanical actuation. Varying the tensile extension of lithiated CFs resulted in a piezoelectric response of the open-circuit potential, in the range of several mV, enabling strain sensing. If the electrical potential is kept constant during a tensile extension a piezo-electrochemical current response is found with about 50% mechanical to electrical energy conversion efficiency, enabling energy harvesting.

  • 11.
    Jacques, Eric
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Hellqvist Kjell, Maria
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Zenkert, Dan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    The effect of lithium-intercalation on the mechanical properties of carbon fibres2014In: Carbon, ISSN 0008-6223, E-ISSN 1873-3891, Vol. 68, p. 725-733Article in journal (Refereed)
    Abstract [en]

    Carbon fibres (CFs) can be used as lightweight structural electrodes since they have high specific tensile stiffness and ultimate tensile strength (UTS), and high lithium (Li)-intercalation capability. This paper investigates the relationship between the amount of intercalated Li and the changes induced in the tensile stiffness and UTS of polyacrylonitrile-based CF tows. After a few electrochemical cycles the stiffness was not degraded and independent of the measured capacity. A drop in the UTS of lithiated CFs was only partly recovered during delithiation and clearly larger at the highest measured capacities, but remained less than 40% at full charge. The reversibility of this drop with the C-rate and measured capacity supports that the fibres are not damaged, that some Li is irreversibly trapped in the delithiated CFs and that reversible strains develop in the fibre. However, the drop in the strength does not vary linearly with the measured capacity and the drop in the ultimate tensile strain remains lower than the CF longitudinal expansion at full charge. These results suggest that the loss of strength might relate to the degree of lithiation of defectives areas which govern the tensile failure mode of the CFs.

  • 12.
    Jacques, Eric
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Hellqvist, Kjell Maria
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Zenkert, Dan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Behm, Mårten
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    PERFORMANCE OF LITHIUM-INTERCALATED CARBONFIBRES FOR STRUCTURAL ELECTRODE APPLICATIONS2013In: ICCM19, 2013, p. 1-8Conference paper (Other academic)
  • 13.
    Jacques, Eric
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Kjell, Maria H.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Zenkert, Dan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Behm, Mårten
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Willgert, Markus
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Impact of electrochemical cycling on the tensile properties of carbon fibres for structural lithium-ion composite batteries2012In: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 72, no 7, p. 792-798Article in journal (Refereed)
    Abstract [en]

    Carbon fibres are particularly well suited for use in a multifunctional lightweight design of a structural composite material able to store energy as a lithium-ion battery. The fibres will in this case act as both a high performance structural reinforcement and one of the battery electrodes. However, the electrochemical cycling consists of insertions and extractions of lithium ions in the microstructure of carbon fibres and its impact on the mechanical performance is unknown. This study investigates the changes in the tensile properties of carbon fibres after they have been subjected to a number of electrochemical cycles. Consistent carbon fibre specimens were manufactured with polyacrylonitrile-based carbon fibres. Sized T800H and desized IMS65 were selected for their mechanical properties and electrochemical capacities. At the first lithiation the ultimate tensile strength of the fibres was reduced of about 20% but after the first delithiation some strength was recovered. The losses and recoveries of strength remained unchanged with the number of cycles as long as the cell capacity remained reversible. Losses in the cell capacity after 1000 cycles were measured together with smaller losses in the tensile strength of the lithiated fibres. These results show that electrochemical cycling does not degrade the tensile properties which seem to depend on the amount of lithium ions inserted and extracted. Both fibre grades exhibited the same trends of results. The tensile stiffness was not affected by the cycling. Field emission scanning electron microscope images taken after electrochemical cycling did not show any obvious damage of the outer surface of the fibres.

  • 14.
    Jacques, Eric
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Kjell, Maria
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Zenkert, Dan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Behm, Mårten
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Expansion of carbon fibres induced by lithium intercalation for structural electrode applications2013In: Carbon, ISSN 0008-6223, E-ISSN 1873-3891, Vol. 59, p. 246-254Article in journal (Refereed)
    Abstract [en]

    Carbon fibres (CFs) can work as lightweight structural electrodes in CF-reinforced composites able to store energy as lithium (Li)-ion batteries. The CF has high stiffness and strength-to-weight ratios and a carbonaceous microstructure which enables Li intercalation. An innovative in situ technique for studying the longitudinal expansion of the CF and the relationship with the amount of intercalated Li is described in the present paper. The polyacrylonitrile-based CFs, T800H and unsized IMS65, were chosen for their electrochemical storage capacities. It was found that the CF expands during lithiation and contracts during delithiation. At the first electrochemical cycle, the expansion is partly irreversible which supports that the first-cycle capacity loss partly relates to Li trapped in the CF structure. For the following cycles, the capacity and the expansion are reversible. The expansion, which might relate to tensile stress, increases up to 1% as the measured capacity approaches the theoretical limit of 372 mAh/g for Li storage in graphite. Minor additional expansions due to the uneven distribution of intercalated Li in the CF structure were measured before and after lithiations. Using scanning electron microscope images the transverse expansion of fully lithiated CFs was estimated to about 10% of the cross-section area.

  • 15.
    Jacques, Eric
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Kjell, Maria
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Zenkert, Dan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Behm, Mårten
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Impact of mechanical loading on the electrochemical behaviour of carbon fibers for use in energy storage composite materials2011In: ICCM18 International Conferences on Composite Materials 18, 2011Conference paper (Refereed)
  • 16.
    Jacques, Eric
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Zenkert, Dan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Leijonmarck, Simon
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Hellqvist Kjell, Maria
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Piezo-Electrochemical Energy Harvesting with Lithium-Intercalating Carbon Fibers2015In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 7, no 25, p. 13898-13904Article in journal (Refereed)
    Abstract [en]

    The mechanical and electrochemical properties are coupled through a piezo-electrochemical effect in Li-intercalated carbon fibers. It is demonstrated that this piezo-electrochemical effect makes it possible to harvest electrical energy from mechanical work. Continuous polyacrylonitrile-based carbon fibers that can work both as electrodes for Li-ion batteries and structural reinforcement for composites materials are used in this study. Applying a tensile force to carbon fiber bundles used as Li-intercalating electrodes results in a response of the electrode potential of a few millivolts which allows, at low current densities, lithiation at higher electrode potential than delithiation. More electrical energy is thereby released from the cell at discharge than provided at charge, harvesting energy from the mechanical work of the applied force. The measured harvested specific electrical power is in the order of 1 muW/g for current densities in the order of 1 mA/g, but this has a potential of being increased significantly.

  • 17. Jacques, Erik
    et al.
    Hellqvist Kjell, Maria
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Zenkert, Dan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Lindberg, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Behm, Mårten
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Performance of lithium-intercalated carbon fibres for structural electrode applications2013In: ICCM International Conferences on Composite Materials, International Committee on Composite Materials , 2013, p. 6852-6859Conference paper (Refereed)
  • 18.
    Kjell, Maria
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Malmgren, Sara
    Uppsala Universitet.
    Ciosek, Katarzyna
    Uppsala Universitet.
    Behm, Mårten
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Edström, Kristina
    Uppsala Universitet.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Comparing aging of MCMB graphite/LiFePO4 cells at 22 °C and 55 °C – Electrochemical and photoelectron spectroscopy studies.Manuscript (preprint) (Other academic)
    Abstract [en]

    Accelerated aging at elevated temperature is commonly used to test lithium-ion battery lifetime, but the effect of an elevated temperature is still not well understood. If aging at elevated temperature would only be faster, but in all other respects equivalent to aging at ambient temperature, cells aged to end-of-life (EOL) at different temperatures would be very similar. The present study compares graphite/LiFePO4-based cells either cycle- or calendar-aged to EOL at 22 °C and 55 °C. Cells cycled at the two temperatures show differences in electrochemical impedance spectra as well as in X-ray photoelectron spectroscopy (XPS) spectra. These results show that lithium-ion cell aging is a complex set of processes. At elevated temperature, the aging is accelerated in process specific ways. Furthermore, the XPS results of cycle-aged samples indicate increased deposition of oxygenated LiPF6 decomposition products in both the negative and positive electrode/electrolyte interfaces. The decomposition seems more pronounced at elevated temperature, and largely accelerated by cycling, which could contribute to the observed cell impedance increase.

  • 19.
    Klett, Matilda
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Zavalis, Tommy
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Hellqvist Kjell, Maria
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Wreland Lindström, Rakel
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Behm, Mårten
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Altered electrode degradation with temperature in LiFePO4/mesocarbon microbead graphite cells diagnosed with impedance spectroscopy2014In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 141, p. 173-181Article in journal (Other academic)
    Abstract [en]

    Electrode degradation in LiFePO4 / mesocarbon microbead graphite (MCMB) pouch cells aged at 55 °C by a synthetic hybrid drive cycle or storage is diagnosed and put into context with previous results of aging at 22 °C. The electrode degradation is evaluated by means of electrochemical impedance spectroscopy (EIS), measured separately on electrodes harvested from the cells, and by using a physics-based impedance model for aging evaluation. Additional capacity measurements, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX) are used in the evaluation. At 55 °C the LiFePO4 electrode shows increased particle/electronic conductor resistance, for both stored and cycled electrodes. This differs from results obtained at 22 °C, where the electrode suffered lowered porosity, particle fracture, and loss of active material. For graphite, only cycling gave a sustained effect on electrode performance at 55 °C due to lowered porosity and changes of surface properties, and to greater extent than at low temperature. Furthermore, increased current collector resistance also contributes to a large part of the pouch cell impedance when aged at increased temperatures. The result shows that increased temperature promotes different degradation on the electrode level, and is an important implication for high temperature accelerated aging. In light of the electrode observations, the correlation between full-cell and electrode impedances is discussed.

  • 20.
    Leijonmarck, Simon
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Carlson, T.
    Hellqvist Kjell, Maria
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Asp, L. E.
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Maples, H.
    Bismarck, A.
    Coated carbon fibre battery half-cells for structural battery composites2013In: ICCM International Conferences on Composite Materials, International Committee on Composite Materials , 2013, p. 5342-5343Conference paper (Refereed)
  • 21.
    Svens, Pontus
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Hellqvist Kjell, Maria
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Tengstedt, Carl
    Flodberg, Göran
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Li-Ion Pouch Cells for Vehicle Applications-Studies of Water Transmission and Packing Materials2013In: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 6, no 1, p. 400-410Article in journal (Refereed)
    Abstract [en]

    This study includes analysis of encapsulation materials from lithium-ion pouch cells and water vapour transmission rate (WVTR) measurements. WVTR measurements are performed on both fresh and environmentally stressed lithium-ion pouch cells. Capacity measurements are performed on both the fresh and the environmentally stressed battery cells to identify possible influences on electrochemical performance. Preparation of the battery cells prior to WVTR measurements includes opening of battery cells and extraction of electrode material, followed by resealing the encapsulations and adhesively mounting of gas couplings. A model describing the water diffusion through the thermal welds of the encapsulation are set up based on material analysis of the encapsulation material. Two WVTR equipments with different type of detectors are evaluated in this study. The results from the WVTR measurements show how important it is to perform this type of studies in dry environment and apply a rigorous precondition sequence before testing. Results from modelling confirm that the WVTR method has potential to be used for measurements of water diffusion into lithium-ion pouch cells. Consequently, WVTR measurements should be possible to use as a complement or alternative method to for example Karl Fisher titration.

  • 22.
    Willgert, Markus
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Hellqvist Kjel, Maria
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Thiol-ene systems in lithium ion conducting thermoset electrolytes2012In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 243Article in journal (Other academic)
  • 23.
    Willgert, Markus
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hellqvist Kjel, Maria
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Photoinduced polymerization of structural lithium-ion battery electrolytes2011In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 241Article in journal (Other academic)
  • 24.
    Willgert, Markus
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Hellqvist Kjell, Maria
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    New approaches for solid polymer electrolytes2012In: ECCM 2012 - Composites at Venice, Proceedings of the 15th European Conference on Composite Materials, European Conference on Composite Materials, ECCM , 2012Conference paper (Refereed)
    Abstract [en]

    In the present study, series of solid polymer electrolytes (SPEs) have been manufactured in a solvent free process through UV curing. All electrolytes are based on poly(ethylene oxide) systems, however the study also investigates the ability to involve thio ethers in the structure as well as inorganic reinforcing particles covalently bonded to the matrix. The SPEs are tested with EIS and DMA to establish the ionic conductivity and mechanical properties. Thio- ethers improve the conductivity but makes the material softer, while particle reinforcement increases the Tg although the ionic conductivity is constant.

  • 25.
    Willgert, Markus
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Hellqvist Kjell, Maria
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    New structural lithium battery electrolytes using thiol-ene chemistry2013In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 236, p. 22-29Article in journal (Refereed)
    Abstract [en]

    A series of solid poly(ethylene oxide)-methacrylate lithium ion electrolytes containing thio-ether segments have successfully been produced and evaluated with respect to mechanical and electrical performance. The series have been varied in crosslink density and thio-ether content. The study presents thiol-ene compounds as yet another tool to design multifunctional electrolytes, and that they are compatible with and usable for polymer electrolyte systems. The electrolytes, produced in a solvent free process where the oligomers are active diluents of the lithium salt, express a broad range of both mechanical as well as ion conducting properties. Conductivity values presented ranges up to about 8 x 10(-7) S/cm, and a wide spectrum of values of the storage modulus is presented in a range from 2 MPa to 2 GPa at 20 degrees C. The influence of the crosslink density of the poly(ethylene oxide)-methacrylates with and without thio-ether segments is discussed. In order to present correlations between crosslink density and how the lithium ion transport is affected by incorporating multifunctional thiol monomers, density measurements have been undertaken to calculate the average molar mass between the crosslinks.

  • 26.
    Willgert, Markus
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Kjell, Maria H.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Jacques, Eric
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Behm, Mårten
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Lindbergh, N. Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Photoinduced free radical polymerization of thermoset lithium battery electrolytes2011In: European Polymer Journal, ISSN 0014-3057, E-ISSN 1873-1945, Vol. 47, no 12, p. 2372-2378Article in journal (Refereed)
    Abstract [en]

    Series of solid poly(ethylene oxide)-methacrylate electrolytes have successfully been manufactured with an aim to serve in a multifunctional battery both as mechanical load carrier as well as lithium ion conductor. The electrolytes produced, in a solvent free process with no post cure swelling, hold a broad range of both mechanical as well as ion conducting properties. The monomer and Li-salt mixtures have been irradiated with UV light, initiating free radical polymerization to obtain solid smooth, homogenous specimens to be utilized as ion conducting electrolytes. The storage modulus at 20 degrees C is ranging from 1 MPa to almost 2 GPa. The conducting ability of the electrolyte ranges from 5.8 x 10(-10) up to 1.5 x 10(-6) S/cm. These large variations in both mechanical properties as well as ionic conductivity are discussed, but also the versatility within the production technique is emphasized.

  • 27.
    Willgert, Markus
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Kjell, Maria H.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Effect of Lithium Salt Content on the Performance of Thermoset Lithium Battery Electrolytes2012In: American Chemical Society Symposium Series (ACS), ISSN 0097-6156, E-ISSN 1947-5918, p. 55-65Article in journal (Refereed)
    Abstract [en]

    Series of solid poly(ethylene glycol)-methacrylate electrolytes have successfully been manufactured in a solvent free process with an aim to serve in a multifunctional battery, both as mechanical load carrier as well as lithium ion conductor. The electrolytes have been studied with respect to mechanical and electrical properties. The thermoset series differs with respect to crosslink density and glass transition temperature (Tg). The results show that the conductivity increases, with salt content exhibiting similar trends, although at overall levels that differ if measured above or below the Tg of the system. The Tg transition on the other hand is more affected by the salt content for loosely crosslinked thermosets. The coordination of a lithium salt to the PEG-segments play a more important role for the physical state of the material when there are less restrictions due to crosslinking of the PEG-chains. The overall performance of the electrolyte at different temperatures will thus be more affected.

  • 28.
    Willgert, Markus
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Kjell, Maria H.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Thiol-ene Systems in Lithium Ion Conducting Thermoset ElectrolytesManuscript (preprint) (Other academic)
  • 29.
    Zavalis, Tommy Georgios
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Klett, Matilda
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Kjell, Maria
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Behm, Mårten
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Wreland Lindström, Rakel
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Aging in Lithium-Ion Batteries: Experimental and Model Investigation of Harvested LiFePO4 and Mesocarbon Microbead Graphite Electrodes2013In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 110, p. 335-348Article in journal (Refereed)
    Abstract [en]

    This study investigates aging in LiFePO4/mesocarbon microbead graphite cells that have been subjected to either a synthetic hybrid drive cycle or calendar aging, at 22 C. The investigation involves detailed examination and comparison of harvested fresh and aged electrodes. The electrode properties are determined using a physics-based electrochemical impedance spectroscopy (EIS) model that is fitted to three-electrode EIS measurements, with input from measured electrode capacity and scanning electrode microscopy (SEM). Results from the model fitting provide a detailed insight to the electrode degradation and is put into context with the behavior of the full cell aging. It was established that calendar aging has negligible effect on cell impedance, while cycle aging increases the impedance mainly due to structural changes in the LiFePO4 porous electrode and electrolyte decomposition products on both electrodes. Further, full-cell capacity fade is mainly a consequence of cyclable lithium loss caused by electrolyte decomposition.

1 - 29 of 29
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf