TY  - JOUR
AU  - Atik, Jaschar
AU  - Winter, Martin
AU  - Paillard, Elie
TI  - Local superconcentration via solvating ionic liquid electrolytes for safe 4.3V lithium metal batteries
JO  - Electrochimica acta
VL  - 415
SN  - 0013-4686
CY  - New York, NY [u.a.]
PB  - Elsevier
M1  - FZJ-2022-01787
SP  - 140181 -
PY  - 2022
AB  - 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.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000872022700001
DO  - DOI:10.1016/j.electacta.2022.140181
UR  - https://juser.fz-juelich.de/record/906974
ER  -