Berlin 2024 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 40: Focus Session: Battery Materials – Experimental Characterisation and Safety Testing (joint session KFM/MM)

MM 40.9: Vortrag

Mittwoch, 20. März 2024, 18:05–18:25, EMH 225

Vacancies on the Lithium-Sublattice in the Solid-State Electrolyte LLZO employing Positron Annihilation Spectroscopy — Dominik Boras¹, Andreas Kohrmann¹, Daniel Wagner¹, Daniel Göbel¹, Janez Kosir², Tanja Kallio², and •Torsten E.M. Staab¹ — ¹Institute for Functional Materials and Biofabrication, Julius-Maximilians Universität Würzburg, D-97070 Würzburg, Röntgenring 11 — ²Department of Chemistry, Aalto University, Kemistintie 1, FIN-02015 Espoo

We characterise the electrolyte LLZO for all solid-state batteries. LLZO (Li₇La₃Zr₂O₁₂) samples have been synthesised via the mixed-oxide route, i.e. grinding and calcination, grinding again, then pressing and finally sintering the pellets. We varied the doping (Fe, Al) and the excess Li content. The formed phases (cubic and tetragonal) have been characterised by XRD, while the lattice defects have been investigated by the method of positron annihilation lifetime spectroscopy (PALS). By PALS we were able to see clear differences after calcination when varying the lithium excess. Measuring powder with increasing Li-excess a lifetime component, which could be related to the bulk crystal significantly decreases from 220ps to 190ps. This may be an indication of more and more filled Li-lattice site after the calcination step. Sintered pellets showed two different positron lifetimes (190 / 200ps and 326 / 374ps) for both un-doped / Al-doped samples. This first attempt shows the potential of PALS to characterise all sold-state electrolytes with respect to defects and the occupation of crystal lattice site influencing the mobility of Li ions.

Keywords: All solid-state batteries; LLZO; solid electrolyte; Positron Annihilation