Browsing by Author "Senyshyn, A."

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    Fatigue processes in commercial LiCoO2 batteries: in situ neutron diffraction and electrochemical study
    (Видавництво Львівської політехніки, 2012) Dolotko, O.; Senyshyn, A.; Mühlbauer, M. J.; Nikolowski, K.; Ehrenberg, H.
    In situ high-resolution neutron powder diffraction along with electrochemical analysis was used to study fatigue processes in commercial LiCoO2 (18650-type) batteries. The electrochemical and structural behavior of cathode and anode materials in fully charged and discharged states has been studied for cells exhibiting different cycling at 25°C and 50°C. High-resolution neutron powder diffraction leads us to observe simultaneous changes in LiCoO2 cathode and graphitic anode, which are related to lithium de-/intercalation processes during the battery operation. Detailed features of the battery organization and details of its evolution on a micrometer scale have been visualized using neutron radiography and tomography.
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    High temperature structure and properties of lithium niobate
    (Національний університет "Львівська політехніка", 2012) Boysen, H.; Senyshyn, A.; Sugak, D. Yu.
    High temperature neutron powder diffraction experiments were carried for a thorough detailed study of the structural evolution and phase transition of lithium niobate. Already at low temperatures part of the Li ions enter the hitherto assumed empty octahedra, their amount increasing with temperature. This explains anomalies in the thermal expansion. The phase transition from the ferroelectric to the paraelectric phase proceeds in two steps, complete disordering of Li before Nb reaches its centrosymmetric site within its octahedron. Li is further disordered within the oxygen plane pointing towards relatively strong Li-O bonds. These results settle a number of controversies found in the literature and add new aspects.
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    In-operando neutron scattering studies of Li-ion batteries
    (Видавництво національного університету „Львівська політехніка”, 2009) Senyshyn, A.; Ehrenberg, H.; Mühlbauer, M.; Fuess, H.
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    Lithium Diffusion Pathways in Modern Solid State Electrolytes
    (2017-05-29) Senyshyn, A.; Monchak, M.; Boysen, H.; Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München; Lichtenbergstr. 1, D-85748 Garching, Germany; Karlsruher Institut für Technologie (KIT), Institut für Angewandte Materialien (IAM); Karlsruhe, Germany; Department für Geo- und Umweltwissenschaften, Sektion Kristallographie, LMU München; Am Coulombwall 6, D-85748 Garching, Germany
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    Structural properties and incommensurate magnetic order in BiFeO3-PbTiO3 solid solutions
    (Видавництво Львівської політехніки, 2012) Senyshyn, A.; Ranjan, R.; Kothai, V.; Daoud-Aladine, A.
    The perovskite BiFeO3 has received considerable attention over decades due to its unique combination of ferroelectric and magnetic properties at room temperature. Recently it has been reported that linear magnetoelectric coupling in BiFeO3 can be realized by artificially introduced disorder like in solid solutions, where PbTiO3 substitution causes an antiferromagnetic (AFM) MH loop. Details of the magnetic and structural order obtained by joint studies using monochromatic highresolution neutron powder diffraction (NPD) and ultra-high resolution TOF NPD on (1-x)BiFeO3-xPbTiO3 solid solutions (x = 0-0.3) have been determined.