SKM 2021 – scientific programme
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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 5: Poster Session KFM
KFM 5.15: Poster
Tuesday, September 28, 2021, 16:00–17:00, P
Spatially-resolved lithium and electrolyte distribution in cylindrical 18650-type lithium-ion batteries — •Dominik Petz1,2, Anatoliy Senyshyn2, and Peter Müller-Buschbaum1,2 — 1Technische Universität München, Garching, Deutschland — 2Heinz Maier-Leibnitz Zentrum, Garching, Deutschland
Extensive cycling of lithium-ion batteries leads to a partial loss of their capacity due to various side effects like formation of the solid-electrolyte-interphase (SEI), loss of active lithium etc. Typical profiles of side reactions, instantaneous temperature and current density display non-uniform distributions throughout the volume, which leads to a stabilization of intrinsic heterogeneous state in the Li-ion battery. The loss of active lithium is typically correlated with the formation of SEI during cycling, whereas the quantitative role of electrolyte in the cell operation and cell fatigue remains not fully quantified yet.
In the current study we report an attempt of non-destructive quantification of lithium and electrolyte, their spatial distribution throughout the cell and concentration changes vs. cell fatigue. Combined experimental studies including electrochemistry, X-ray computed tomography, and neutron diffraction are applied for 18650-type cylinder cell with NCA|C chemistry. High-resolution neutron diffraction independently reveals a direct volume-averaged correlation between losses of active lithium in the graphite anode and these of the liquid electrolyte. The 3D lithium distribution is mapped by spatially resolved neutron powder diffraction, displaying the non-trivial character of active lithium and electrolyte losses.