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Unraveling and mitigating the storage instability of fluoroethylene carbonate-containing LiPF6 electrolytes to stabilize lithium metal anodes for high-temperature rechargeable batteries
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SYSNO ASEP 0507026 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Unraveling and mitigating the storage instability of fluoroethylene carbonate-containing LiPF6 electrolytes to stabilize lithium metal anodes for high-temperature rechargeable batteries Author(s) Xu, C. (SE)
Hernández, G. (SE)
Abbrent, Sabina (UMCH-V) RID, ORCID
Kobera, Libor (UMCH-V) RID, ORCID
Konefal, Rafal (UMCH-V) RID, ORCID
Brus, Jiří (UMCH-V) RID, ORCID
Edström, K. (SE)
Brandell, D. (SE)
Mindemark, J. (SE)Source Title ACS Applied Energy Materials. - : American Chemical Society - ISSN 2574-0962
Roč. 2, č. 7 (2019), s. 4925-4935Number of pages 11 s. Language eng - English Country US - United States Keywords lithium metal batteries ; thermal instability ; electrolyte storage instability Subject RIV CD - Macromolecular Chemistry OECD category Polymer science R&D Projects GA18-12925S GA ČR - Czech Science Foundation (CSF) Method of publishing Limited access Institutional support UMCH-V - RVO:61389013 UT WOS 000477074700040 EID SCOPUS 85070545529 DOI 10.1021/acsaem.9b00607 Annotation Implementing Li metal anodes provides the potential of substantially boosting the energy density of current Li-ion battery technology. However, it suffers greatly from fast performance fading largely due to substantial volume change during cycling and the poor stability of the solid electrolyte interphase (SEI). Fluoroethylene carbonate (FEC) is widely acknowledged as an effective electrolyte additive for improving the cycling performance of batteries consisting of electrode materials that undergo large volume changes during cycling such as Li metal. In this study, we report that while FEC can form a robust SEI on the electrode, it also deteriorates the shelf life of electrolytes containing LiPF6. The degradation mechanism of LiPF6 in FEC solutions is unraveled by liquid- and solid-state NMR. Specifically, traces of water residues induce the hydrolysis of LiPF6, releasing HF and PF5 which further trigger ring-opening of FEC and its subsequent polymerization. These reactions are significantly accelerated at elevated temperatures leading to the formation of a three-dimensional fluorinated solid polymer network. Moisture scavenger additives, such as lithium 4,5-dicyano-2-(trifluoromethyl)imidazole (LiTDI), can delay the degradation reaction as well as improve the cycling stability of LiNi1/3Mn1/3Co1/3O2/Li metal batteries at 55 °C. This work highlights the poor shelf life of electrolytes containing FEC in combination with LiPF6 and thereby the great importance of developing proper storage methods as well as optimizing the content of FEC in practical cells. Workplace Institute of Macromolecular Chemistry Contact Eva Čechová, cechova@imc.cas.cz ; Tel.: 296 809 358 Year of Publishing 2020 Electronic address https://pubs.acs.org/doi/10.1021/acsaem.9b00607
Number of the records: 1