On the Surface Modification of LLZTO with LiF via a Gas-Phase Approach and the Characterization of the Interfaces of LiF with LLZTO as Well as PEO+LiTFSI

Manuel Donzelli; Thimo Ferber; Vanita Vanita; Aamir Iqbal Waidha; Philipp Müller; Maximilian Mellin; René Hausbrand; Wolfram Jaegermann; Oliver Clemens

doi:10.3390/ma15196900

On the Surface Modification of LLZTO with LiF via a Gas-Phase Approach and the Characterization of the Interfaces of LiF with LLZTO as Well as PEO+LiTFSI

Materials (Basel). 2022 Oct 5;15(19):6900. doi: 10.3390/ma15196900.

Authors

Manuel Donzelli^{1

2}, Thimo Ferber³, Vanita Vanita², Aamir Iqbal Waidha², Philipp Müller³, Maximilian Mellin³, René Hausbrand³, Wolfram Jaegermann³, Oliver Clemens²

Affiliations

¹ Fachgebiet Materialdesign Durch Synthese, Fachbereich Materialwissenschaft, Technische Universität Darmstadt, Alarich-Weiss-Straße 2, 64287 Darmstadt, Germany.
² Chemische Materialsynthese, Institut für Materialwissenschaft, Universität Stuttgart, Heisenbergstraße 3, 70569 Stuttgart, Germany.
³ Fachgebiet Oberflächenforschung, Fachbereich Materialwissenschaft, Technische Universität Darmstadt, Otto-Berndt-Straße 3, 64287 Darmstadt, Germany.

Abstract

In this study we present gas-phase fluorination as a method to create a thin LiF layer on Li_6.5La₃Zr_1.5Ta_0.5O₁₂ (LLZTO). We compared these fluorinated films with LiF films produced by RF-magnetron sputtering, where we investigated the interface between the LLZTO and the deposited LiF showing no formation of a reaction layer. Furthermore, we investigated the ability of this LiF layer as a protection layer against Li₂CO₃ formation in ambient air. By this, we show that Li₂CO₃ formation is absent at the LLZTO surface after 24 h in ambient air, supporting the protective character of the formed LiF films, and hence potentially enhancing the handling of LLZTO in air for battery production. With respect to the use within hybrid electrolytes consisting of LLZTO and a mixture of polyethylene oxide (PEO) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), we also investigated the interface between the formed LiF films and a mixture of PEO+LiTFSI by X-ray photoelectron spectroscopy (XPS), showing decomposition of the LiTFSI at the interface.

Keywords: LLZTO; XPS; fluorination; interface stability; surface modification.

Abstract

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