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Suche nach „[A.] [Dunst]“ hat 11 Publikationen gefunden
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    MobilNachhaltigTC Plattling MoMo

    Vortrag

    A. Dunst, Michael Sternad, V. Epp, M. Wilkening

    Fast Li Self-Diffusion in Amorphous Li-Si Electrochemically Prepared from Semiconductor Grade, Monocrystalline Silicon — Insights from Spin-Locking Nuclear Magnetic Relaxometry

    Poster presentation

    20th International Conference on Solid State Ionics, Keystone, CO, USA

    MobilNachhaltigTC Plattling MoMo

    Vortrag

    Michael Sternad, G. Schrotter, A. Dunst, R. Janski, M. Forster, B. Goller, et al.

    Crystalline Silicon as Structured Anode Material for Lithium-Ion Batteries

    224th Meeting of the Electrochemical Society, San Francisco, CA, USA

    MobilNachhaltigTC Plattling MoMo

    Patent

    Michael Sternad, R. Janski, K. Schmut, M. Wilkening, K. Karlovsky, M. Sorger, A. Dunst, G. Hirtler

    VERFAHREN ZUM HERSTELLEN EINER BATTERIE, BATTERIE UND INTEGRIERTE SCHALTUNG.

    MobilNachhaltigTC Plattling MoMo

    Patent

    K. Karlovsky, A. Dunst, G. Hirtler, R. Janski, K. Schmut, M. Sorger, Michael Sternad, M. Wilkening

    METHOD OF MANUFACTURING A BATTERY, BATTERY AND INTEGRATED CIRCUIT

    MobilNachhaltigTC Plattling MoMo

    Zeitschriftenartikel

    R. Janski, M. Fugger, M. Forster, M. Sorger, A. Dunst, I. Hanzu, Michael Sternad, M. Wilkening

    Lithium barrier materials for on-chip Si-based microbatteries

    Journal of Materials Science: Materials in Electronics, vol. 28, no. 19, pp. 14605-14614

    DOI: 10.1007/s10854-017-7325-4

    Abstract anzeigen

    The integration of lithium-ion batteries, featuring ultra-high discharge rates, directly into silicon-based semiconductor devices opens unique paths towards the development of new mobile micro-electronics applications. Nevertheless, the small and mobile lithium ions have to be confined within the battery area of the silicon chip, otherwise the nearby fine microelectronics devices will be irreversibly damaged. Hence, a barrier material that blocks Li+ transport from the active components of the battery into the surrounding crystalline Si is needed. Here we evaluated the capability of magnetron sputtered barrier films of nitrides and alloys of refractory metals to prevent lithium ion diffusion and, thus, the formation of Li–Si phases outside the battery area. In order to determine the Li profiles in the barrier layer and in the silicon substrate, time-of-flight secondary ion mass spectroscopy was applied for profiling the first microns. In combination with electrochemical testing it turned out that titanium nitride as well as tantalum nitride barriers are able to significantly block Li ion migration.

    MobilNachhaltigTC Plattling MoMo

    Zeitschriftenartikel

    A. Dunst, Michael Sternad, M. Wilkening

    Overall conductivity and NCL-type relaxation behavior in nanocrystalline sodium peroxide Na 2 O 2 —Consequences for Na-oxygen batteries

    Materials Science and Engineering: B, vol. 211, no. September, pp. 85-93

    DOI: 10.1016/j.mseb.2016.06.002

    Abstract anzeigen

    Metal air batteries are considered as promising candidates for room-temperature batteries with high-energy densities. On discharge, atmospheric oxygen is reduced at the positive electrode which, in the ideal case, forms the discharge products in a reversible cell reaction. In Na-O2 batteries upon discharge either sodium peroxide (Na2O2) or sodium superoxide (NaO2) is reported to be formed. So far, the charge carrier transport remains relatively unexplored but is expected to crucially determine the efficiency of such energy storage systems. Na2O2 is predicted to be an electrical insulator wherein the transport presumably is determined by very slow hopping processes. Understanding the basic fundamental properties of the overall charge carrier transport, including also nanostructured forms of Na2O2, is key to developing high-energy metal oxygen batteries. The present study answers the question how overall, i.e., total, conductivity changes when going from microcrystalline to nanocrystalline, defect-rich Na2O2. Nanocrystalline Na2O2 was prepared via a top-down approach, viz by high-energy ball milling. Milling does not only shrink the average crystallite diameter but also introduces a large amount of defects which are anticipated to influence total conductivity. It turned out that even after vigorous mechanical treatment the conductivity of the sample is only increased by ca. one order of magnitude. The activation energy remains almost untouched. Thus, the increase seen might be attributed to an enhanced number of charge carriers. Low-temperature data reveals nearly constant loss relaxation behavior which has frequently explained in terms of strictly localized electrical relaxation processes.

    MobilNachhaltigTC Plattling MoMo

    Zeitschriftenartikel

    A. Dunst, Michael Sternad, V. Epp, M. Wilkening

    Fast Li+ Self-Diffusion in Amorphous Li–Si Electrochemically Prepared from Semiconductor Grade, Monocrystalline Silicon: Insights from Spin-Locking Nuclear Magnetic Relaxometry

    The Journal of Physical Chemistry C, vol. 119, no. 22, pp. 12183-12192

    DOI: 10.1021/acs.jpcc.5b02490

    Abstract anzeigen

    Silicon is one of the most promising anode materials for lithium-based rechargeable batteries. Provided the volume changes during Li uptake can be brought under control, Li ion diffusivity is expected to crucially determine the performance of such next-generation energy storage systems. Therefore, studying diffusion properties in e.g. amorphous Li–Si underpins applied research that is being directed toward the development of powerful storage devices. So far, only little information is available on Li+ self-diffusion in amorphous Si. Here, we used 7Li NMR spectroscopy to precisely quantify microscopic activation energies and Li jump rates in amorphous Li–Si which is primarily formed if monocrystalline Si is lithiated electrochemically. Surprisingly, our results reveal relatively fast Li ion diffusivity with low activation energies for localized Li+ motions being in agreement with results from theory. The average activation energy for long-range ion transport is as high as ca. 0.65 eV; jump rates turn out to be in the order of 2.5 × 105 s–1 at 246 K. Our results point to complex dynamics that is most likely governed by nonexponential motional correlation functions originating from a distribution of activation energies. The data obtained might help optimizing Li-based silicon batteries whose performance critically depend on fast Li ion transport.

    MobilNachhaltigTC Plattling MoMo

    Vortrag

    A. Dunst, Michael Sternad, V. Epp, M. Wilkening

    Li Self-Diffusion in Metastable Li15Si4 prepared from Monocrystalline Si - An Ex Situ 7Li NMR Relaxometry Study

    Poster presentation

    17th International Meeting on Lithium Batteries, Como, Italien

    MobilNachhaltigTC Plattling MoMo

    Vortrag

    A. Dunst, Michael Sternad, V. Epp, M. Wilkening

    Li Self-Diffusion in Amorphous Li/Si Prepared from Monocrystalline Si - A 7Li NMR Relaxometry Study

    Poster presentation

    65th Annual Metting of the International Society of Electrochemistry (ISE), Lausanne, Schweiz

    MobilNachhaltigTC Plattling MoMo

    Vortrag

    A. Dunst, Michael Sternad, V. Epp, M. Wilkening

    Lithium ion dynamics in amorphous Li-Si electrochemically prepared from semiconductor grade, monocrystalline silicon — An NMR Study

    Poster presentation

    Materials Day 2015, Graz, Österreich

    MobilNachhaltigTC Plattling MoMo

    Vortrag

    A. Dunst, Michael Sternad, V. Epp, M. Wilkening

    Fast Li self-diffusion in Li-Si Electrochemically Prepared from Semiconductor Grade, Monocrystalline Silicon

    15th European Conference on Solid State Chemistry (ECSSC), Wien, Österreich