Miß, Vanessa ; Neuberger, Sven ; Winter, Edda ; Weiershäuser, Jan Ole ; Gerken, Dilnoza ; Xu, Yang ; Krüger, Sandra ; Capua, Francesco di ; Vogel, Michael ; Schmedt auf der Günne, Jörn ; Roling, Bernhard (2022)
Heat Treatment-Induced Conductivity Enhancement in Sulfide-Based Solid Electrolytes: What is the Role of the Thio-LISICON II Phase and of Other Nanoscale Phases?
In: Chemistry of Materials, 34 (17)
doi: 10.1021/acs.chemmater.2c00908
Artikel, Bibliographie
Kurzbeschreibung (Abstract)
Sulfide-based solid Li+ electrolytes are one of the most promising electrolyte classes for solid-state battery applications. These solid electrolytes are typically prepared by means of high-energy ball milling, often followed by a heat treatment step for enhancing the Li+ ion conductivity. In many cases, heat treatment-induced conductivity enhancements have been attributed to the formation of a superionic thio-LISICON II phase. However, the chemical composition and structure of this phase as well as the origin of the conductivity enhancement are still under debate. Here, we have carried out a comprehensive study on the thiophosphate-based electrolyte system (1 – x) Li3PS4 + x LiI with x = 0–0.5. By combining electrochemical impedance spectroscopy, X-ray diffraction, and Raman spectroscopy as well as 7Li NMR line-shape analysis and high-resolution multidimensional 31P solid-state NMR measurements, we show that the widely used concept of a thio-LISICON II phase governing the ionic conductivity of heat-treated samples cannot explain the experimental observations. Double-quantum constant-time 31P NMR proves that P2S64– units are embedded in the amorphous phase of the ball-milled pristine samples. Upon heat treatment, the amorphous phase with the embedded P2S64– units is transformed into different nanoscale crystalline phases, a thio-LISICON II phase, a β-Li3PS4 phase, and a Li4PS4I-related phase. A structural model of the thio-LISICON II phase needs to explain the coupling pattern from two-dimensional double-quantum NMR presented here, showing two phosphorus environments with an approximate ratio of 2:1. Furthermore, our results indicate that in heat-treated samples, a highly disordered nanoscale Li4PS4I-related phase exists with an ionic conductivity even exceeding that of the thio-LISICON II phase
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2022 |
| Autor(en): | Miß, Vanessa ; Neuberger, Sven ; Winter, Edda ; Weiershäuser, Jan Ole ; Gerken, Dilnoza ; Xu, Yang ; Krüger, Sandra ; Capua, Francesco di ; Vogel, Michael ; Schmedt auf der Günne, Jörn ; Roling, Bernhard |
| Art des Eintrags: | Bibliographie |
| Titel: | Heat Treatment-Induced Conductivity Enhancement in Sulfide-Based Solid Electrolytes: What is the Role of the Thio-LISICON II Phase and of Other Nanoscale Phases? |
| Sprache: | Englisch |
| Publikationsjahr: | 13 September 2022 |
| Verlag: | ACS |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | Chemistry of Materials |
| Jahrgang/Volume einer Zeitschrift: | 34 |
| (Heft-)Nummer: | 17 |
| DOI: | 10.1021/acs.chemmater.2c00908 |
| Kurzbeschreibung (Abstract): | Sulfide-based solid Li+ electrolytes are one of the most promising electrolyte classes for solid-state battery applications. These solid electrolytes are typically prepared by means of high-energy ball milling, often followed by a heat treatment step for enhancing the Li+ ion conductivity. In many cases, heat treatment-induced conductivity enhancements have been attributed to the formation of a superionic thio-LISICON II phase. However, the chemical composition and structure of this phase as well as the origin of the conductivity enhancement are still under debate. Here, we have carried out a comprehensive study on the thiophosphate-based electrolyte system (1 – x) Li3PS4 + x LiI with x = 0–0.5. By combining electrochemical impedance spectroscopy, X-ray diffraction, and Raman spectroscopy as well as 7Li NMR line-shape analysis and high-resolution multidimensional 31P solid-state NMR measurements, we show that the widely used concept of a thio-LISICON II phase governing the ionic conductivity of heat-treated samples cannot explain the experimental observations. Double-quantum constant-time 31P NMR proves that P2S64– units are embedded in the amorphous phase of the ball-milled pristine samples. Upon heat treatment, the amorphous phase with the embedded P2S64– units is transformed into different nanoscale crystalline phases, a thio-LISICON II phase, a β-Li3PS4 phase, and a Li4PS4I-related phase. A structural model of the thio-LISICON II phase needs to explain the coupling pattern from two-dimensional double-quantum NMR presented here, showing two phosphorus environments with an approximate ratio of 2:1. Furthermore, our results indicate that in heat-treated samples, a highly disordered nanoscale Li4PS4I-related phase exists with an ionic conductivity even exceeding that of the thio-LISICON II phase |
| Fachbereich(e)/-gebiet(e): | 05 Fachbereich Physik 05 Fachbereich Physik > Institut für Physik Kondensierter Materie (IPKM) 05 Fachbereich Physik > Institut für Physik Kondensierter Materie (IPKM) > Molekulare Dynamik in kondensierter Materie |
| Hinterlegungsdatum: | 17 Jun 2024 13:37 |
| Letzte Änderung: | 17 Jun 2024 13:37 |
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