| 1. |
- Leon, G., et al.
(författare)
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Aspects of power system modeling, initialization and simulation using the Modelica language
- 2015
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Ingår i: 2015 IEEE Eindhoven PowerTech, PowerTech 2015. - : IEEE conference proceedings. - 9781479976935
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Konferensbidrag (refereegranskat)abstract
- A medium sized power system, with a large number of devices, is fully modeled and simulated in Modelica. For this, new models for electrical components and mathematical blocks were developed in Modelica and the full system topology and parameters were taken from a reference system made in Eurostag. Initialization and time-domain simulations are performed in a Modelica simulation environment and the results obtained for the steady-state and the response to time-events are compared and validated with simulations performed in Eurostag.
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| 2. |
- Seymour, Ieuan D., et al.
(författare)
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Characterizing Oxygen Local Environments in Paramagnetic Battery Materials via O-17 NMR and DFT Calculations
- 2016
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 138:30, s. 9405-9408
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Tidskriftsartikel (refereegranskat)abstract
- Experimental techniques that probe the local environment around O in paramagnetic Li-ion cathode materials are essential in order to understand the complex phase transformations and O redox processes that can occur during electrochemical delithiation. While Li NMR is a well-established technique for studying the local environment of Li ions in paramagnetic battery materials, the use of O-17 NMR in the same materials has not yet been reported. In this work, we present a combined O-17 NMR and hybrid density functional theory study of the local O environments in Li2MnO3, a model compound for layered Li-ion batteries. After a simple O-17 enrichment procedure, we observed five resonances with large O-17 shifts ascribed to the Fermi contact interaction with directly bonded Mn4+ ions. The five peaks were separated into two groups with shifts at 1600 to 1950 ppm and 2100 to 2450 ppm, which, -with the aid of first principles calculations, were assigned to the O-17 shifts of environments similar to the 4i and 8j sites in pristine Li2MnO3, respectively. The multiple O environments in each region were ascribed to the presence of stacking faults within the Li2MnO3 structure. From the ratio of the intensities of the different O-17 environments, the percentage of stacking faults was found to be ca. 10%. The methodology for studying (17)Oshifts in paramagnetic solids described in this work will be useful for studying the local environments of O in a range of technologically interesting transition metal oxides.
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| 3. |
- Halat, David M., et al.
(författare)
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Natural abundance solid-state S-33 NMR study of NbS3: applications for battery conversion electrodes
- 2019
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Ingår i: Chemical Communications. - : Royal Society of Chemistry (RSC). - 1364-548X .- 1359-7345. ; 55:84, s. 12687-12690
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Tidskriftsartikel (refereegranskat)abstract
- We report ultra-wideline, high-field natural abundance solid-state S-33 NMR spectra of the Li-ion battery conversion electrode NbS3, the first S-33 NMR study of a compound containing disulfide (S-2(2-)) units. The large quadrupolar coupling parameters (C-Q approximate to 31 MHz) are consistent with values obtained from DFT calculations, and the spectra provide evidence for the linear Peierls distortion that doubles the number of S-33 sites.
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