Journal Article

FZJ-2022-01787

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Local superconcentration via solvating ionic liquid electrolytes for safe 4.3V lithium metal batteries

Atik, J.FZJ* ; Winter, M.FZJ* ; Paillard, E. (Corresponding author)

2022
Elsevier New York, NY [u.a.]

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Please use a persistent id in citations: http://hdl.handle.net/2128/30957  doi:10.1016/j.electacta.2022.140181

Abstract: A novel solvating ionic liquid (SIL), N-methyl N-oligo(ethylene oxide)pyrrolidinium bis(fluorosulfonyl)imide (Pyr1,(2O)7FSI) was synthesized and used to prepare binary and ternary liquid electrolytes with LiFSI as conducting salt and 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether (TTE) as a non-solvating low viscosity co-solvent. Thereby, the binary superconcentrated liquid electrolyte (i.e., 6.8 m LiFSI in Pyr1,(2O)7FSI) reaches a Li+ ion transference number of 0.25 ± 0.02. To enhance the ionic conductivity and separator wetting, the binary electrolyte was mixed with TTE leading to local superconcentrated Li+ ion solvation structures as shown by Raman measurements. These ternary electrolytes exhibit improved wettability, excellent safety and allow cycling in NMC622||Li cells and Cu||Li cells with Coulombic efficiencies of up to 99.9% and 98.5%, respectively, and a capacity retention of 84% for NMC622||Li cells with the electrolyte 2.0 m LiFSI, Pyr1,(2O)7FSI:TTE (1:1 wt%) after 100 cycles vs. a cell failure after 35 cycles for the state-of-the-art containing IL N‑butyl‑N-methylpyrrolidinium FSI electrolyte.

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Contributing Institute(s):

1. Helmholtz-Institut Münster Ionenleiter für Energiespeicher (IEK-12)

Research Program(s):

1. 1221 - Fundamentals and Materials (POF4-122) (POF4-122)

Appears in the scientific report 2022

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; ; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; Essential Science Indicators ; IF >= 5 ; JCR ; Nationallizenz ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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