SKM 2023 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 16: Energy Conversion
MM 16.4: Vortrag
Dienstag, 28. März 2023, 11:00–11:15, SCH A 215
Detailed structural and electrochemical comparison between high potential layered P2-NaMnNi- and doped P2-NaMnNiMg-oxides — •Manuel Dillenz1, Cornelius Gauckler2, Mohsen Sotoudeh1, Holger Euchner3, Mario Marinaro2, and Axel Groß1,4 — 1Institute of Theoretical Chemistry, Ulm University, Mez-Starck-Haus, Oberberghof 7, 89081 Ulm — 2ZSW-Zentrum für Sonnenenergie und Wasserstoff-Forschung, Helmholtzstrasse 8, 89081, Ulm, Germany — 3Institute of Physical and Theoretical Chemistry, Universität Tübingen, Auf der Morgenstelle 15, 72076 Tübingen, Germany — 4Helmholtz Institute Ulm (HIU) for Electrochemical Energy Storage, Helmholtzstraße 11, 89069 Ulm, Germany
Manganese-based transition metal oxides with a P2 structure are promising cathode materials for sodium ion batteries. Although these materials exhibit high working potential vs Na+/Na and high capacity, they are affected by Na+ ion/vacancy ordering transitions and phase transformations at high voltages, resulting in poor reversibility. Here we present a combined experimental/theoretical approach to investigate the effect of magnesium doping on the layered P2-Na0.67Mn0.75Ni0.25O2 cathode material. The Mg-doped material showed stabilization of the high potential plateau and improved cycle life. Based on our experimental data and periodic density functional theory (DFT) calculations, phase stabilities of the O2, P2, and OP4 phases for the pristine and Mg-doped systems were investigated to elucidate the origin of the "Z"-phase formation in the Mg-doped systems.