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Donzelli M, Ferber T, Vanita V, Waidha AI, Müller P, Mellin M, Hausbrand R, Jaegermann W, Clemens O. 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, SWITZERLAND) 2022; 15:6900. [PMID: 36234240 PMCID: PMC9570571 DOI: 10.3390/ma15196900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 09/16/2022] [Accepted: 09/18/2022] [Indexed: 06/16/2023]
Abstract
In this study we present gas-phase fluorination as a method to create a thin LiF layer on Li6.5La3Zr1.5Ta0.5O12 (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.
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Affiliation(s)
- Manuel Donzelli
- Fachgebiet Materialdesign Durch Synthese, Fachbereich Materialwissenschaft, Technische Universität Darmstadt, Alarich-Weiss-Straße 2, 64287 Darmstadt, Germany
- Chemische Materialsynthese, Institut für Materialwissenschaft, Universität Stuttgart, Heisenbergstraße 3, 70569 Stuttgart, Germany
| | - Thimo Ferber
- Fachgebiet Oberflächenforschung, Fachbereich Materialwissenschaft, Technische Universität Darmstadt, Otto-Berndt-Straße 3, 64287 Darmstadt, Germany
| | - Vanita Vanita
- Chemische Materialsynthese, Institut für Materialwissenschaft, Universität Stuttgart, Heisenbergstraße 3, 70569 Stuttgart, Germany
| | - Aamir Iqbal Waidha
- Chemische Materialsynthese, Institut für Materialwissenschaft, Universität Stuttgart, Heisenbergstraße 3, 70569 Stuttgart, Germany
| | - Philipp Müller
- Fachgebiet Oberflächenforschung, Fachbereich Materialwissenschaft, Technische Universität Darmstadt, Otto-Berndt-Straße 3, 64287 Darmstadt, Germany
| | - Maximilian Mellin
- Fachgebiet Oberflächenforschung, Fachbereich Materialwissenschaft, Technische Universität Darmstadt, Otto-Berndt-Straße 3, 64287 Darmstadt, Germany
| | - René Hausbrand
- Fachgebiet Oberflächenforschung, Fachbereich Materialwissenschaft, Technische Universität Darmstadt, Otto-Berndt-Straße 3, 64287 Darmstadt, Germany
| | - Wolfram Jaegermann
- Fachgebiet Oberflächenforschung, Fachbereich Materialwissenschaft, Technische Universität Darmstadt, Otto-Berndt-Straße 3, 64287 Darmstadt, Germany
| | - Oliver Clemens
- Chemische Materialsynthese, Institut für Materialwissenschaft, Universität Stuttgart, Heisenbergstraße 3, 70569 Stuttgart, Germany
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Wollstadt S, Ikeda Y, Sarkar A, Vasala S, Fasel C, Alff L, Kruk R, Grabowski B, Clemens O. Structural and Magnetic Properties of BaFeO 2.667 Synthesized by Oxidizing BaFeO 2.5 Obtained via Nebulized Spray Pyrolysis. Inorg Chem 2021; 60:10923-10933. [PMID: 34240868 DOI: 10.1021/acs.inorgchem.1c00434] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A vacancy-ordered perovskite-type compound Ba3Fe3O8 (BaFeO2.667) was prepared by oxidizing BaFeO2.5 (P21/c) with the latter compound obtained by a spray pyrolysis technique. The structure of Ba3Fe3O8 was found to be isotypic to Ba3Fe3O7F (P21/m) and can be written as Ba3Fe3+2Fe4+1O8. Mössbauer spectroscopy and ab initio calculations were used to confirm mixed iron oxidation states, showing allocation of the tetravalent iron species on the tetrahedral site, and octahedral as well as square pyramidal coordination for the trivalent species within a G-type antiferromagnetic ordering. The uptake and release of oxygen were investigated over a broad temperature range from room temperature to 1100 °C under pure oxygen and ambient atmosphere via a combination of DTA/TG and variable temperature diffraction measurements. The compound exhibited a strong lattice enthalpy driven reduction to monoclinic and cubic BaFeO2.5 at elevated temperatures.
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Affiliation(s)
- Stephan Wollstadt
- Institute for Materials Science, Materials Synthesis Group, University of Stuttgart, Heisenbergstraße 3, Stuttgart 70569, Germany.,Institut für Materialwissenschaft, Fachgebiet Materialdesign durch Synthese, Technical University of Darmstadt, Alarich-Weiss-Straße 2, Darmstadt 64287, Germany
| | - Yuji Ikeda
- Institute for Materials Science, Department of Materials Design, University of Stuttgart, Pfaffenwaldring 55, Stuttgart 70569, Germany
| | - Abhishek Sarkar
- Institut für Nanotechnologie, Karlsruher Institut für Technologie, Hermann-von-Helmholtz-Platz 1, Eggenstein Leopoldshafen 76344, Germany.,Institut für Materialwissenschaft, Gemeinschaftslabor Nanomaterialien, Technical University of Darmstadt, Alarich-Weiss-Straße 2, Darmstadt 64287, Germany
| | - Sami Vasala
- Institut für Materialwissenschaft, Fachgebiet Materialdesign durch Synthese, Technical University of Darmstadt, Alarich-Weiss-Straße 2, Darmstadt 64287, Germany
| | - Claudia Fasel
- Institut für Materialwissenschaft, Fachgebiet Disperse Feststoffe, Technical University of Darmstadt Alarich-Weiss-Straße 2, 64287 Darmstadt, Germany
| | - Lambert Alff
- Institut für Materialwissenschaft, Advanced Thin Film Technology, Technical University of Darmstadt Alarich-Weiss-Straße 2, 64287 Darmstadt, Germany
| | - Robert Kruk
- Institut für Nanotechnologie, Karlsruher Institut für Technologie, Hermann-von-Helmholtz-Platz 1, Eggenstein Leopoldshafen 76344, Germany
| | - Blazej Grabowski
- Institute for Materials Science, Department of Materials Design, University of Stuttgart, Pfaffenwaldring 55, Stuttgart 70569, Germany
| | - Oliver Clemens
- Institute for Materials Science, Materials Synthesis Group, University of Stuttgart, Heisenbergstraße 3, Stuttgart 70569, Germany.,Institut für Materialwissenschaft, Fachgebiet Materialdesign durch Synthese, Technical University of Darmstadt, Alarich-Weiss-Straße 2, Darmstadt 64287, Germany
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Wollstadt S, Clemens O. On the Impact of the Degree of Fluorination on the ORR Limiting Processes within Iron Based Catalysts: A Model Study on Symmetrical Films of Barium Ferrate. MATERIALS (BASEL, SWITZERLAND) 2020; 13:E2532. [PMID: 32503126 PMCID: PMC7321444 DOI: 10.3390/ma13112532] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 05/25/2020] [Accepted: 05/28/2020] [Indexed: 12/21/2022]
Abstract
In this study, symmetrical films of BaFeO2.67, BaFeO2.33F0.33 and BaFeO2F were synthesized and the oxygen uptake and conduction was investigated by high temperature impedance spectroscopy under an oxygen atmosphere. The data were analyzed on the basis of an impedance model designed for highly porous mixed ionic electronic conducting (MIEC) electrodes. Variable temperature X-ray diffraction experiments were utilized to estimate the stability window of the oxyfluoride compounds, which yielded a degradation temperature for BaFeO2.33F0.33 of 590 °C and a decomposition temperature for BaFeO2F of 710 °C. The impedance study revealed a significant change of the catalytic behavior in dependency of the fluorine content. BaFeO2.67 revealed a bulk-diffusion limited process, while BaFeO2.33F0.33 appeared to exhibit a fast bulk diffusion and a utilization region δ larger than the electrode thickness L (8 μm). In contrast, BaFeO2F showed very area specific resistances due to the lack of oxygen vacancies. The activation energy for the uptake and conduction process of oxygen was found to be 0.07/0.29 eV (temperature range-dependent), 0.33 eV and 0.67 eV for BaFeO2.67, BaFeO2.33F0.33 and BaFeO2F, respectively.
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Affiliation(s)
- Stephan Wollstadt
- Fachgebiet Materialdesign Durch Synthese, Institut für Materialwissenschaft, Technical University of Darmstadt, 64287 Darmstadt, Germany;
| | - Oliver Clemens
- Fachgebiet Materialdesign Durch Synthese, Institut für Materialwissenschaft, Technical University of Darmstadt, 64287 Darmstadt, Germany;
- Institut für Nanotechnologie, Karlsruher Institut für Technologie, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein Leopoldshafen, Germany
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