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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 19: Energy Storage and Batteries II

CPP 19.5: Talk

Tuesday, March 19, 2024, 10:30–10:45, H 0111

Dynamic Structure Evolution of Extensively Delithiated High Voltage Spinel — Nicola Jobst¹, •Neelima Paul², Premsyl Beran³, Marilena Mancini¹, Ralph Gilles², Margret Wohlfahrt-Mehrens¹, and Peter Axmann¹ — ¹Zentrum für Sonnenenergie- und Wasserstoff- Forschung Baden-Württemberg, Ulm — ²Heinz Maier-Leibnitz Zentrum, Technische Universität München, Garching — ³Nuclear Physics Institute, Czech Republic & European Spallation Source ,Lund

High voltage spinel is one of the most promising next-generation cobalt-free cathode materials for lithium ion battery applications. Besides the typically utilized compositional range of LixNi0.5Mn1.5O4 0 < x < 1 , additional 1.5 mol of Li per formula unit can be introduced into the structure in an extended voltage range upto 1.50 V. Theoretically, this leads to significant increase of the specific energy from 690 to 1190 Wh/kg. However, utilization of the extended potential window leads to rapid capacity fading and voltage polarization that lack a comprehensive explanation. In this work, we conducted potentiostatic entropymetry, operando XRD and neutron diffraction on the ordered stoichiometric spinel LixNi0.5Mn1.5O4 within 0 < x < 2.5 in order to understand the dynamic structure evolution and correlate it with the voltage profile. During the two-phase reaction from cubic (x < 1) to tetragonal (x > 1) phase at ~2.8 V, we identified the evolution of a second tetragonal phase with x > 2. Evaluation of neutron diffraction data reveal location of additional lithium ions.

Keywords: Cathode; Li ion battery; Neutron diffraction; X-ray diffraction; Spinel