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@ARTICLE{Krmer:1025065,
author = {Krämer, Susanna and Daniliuc, Constantin G. and Winter,
Martin and Wiemhöfer, Hans-Dieter and Gruenebaum, Mariano},
title = {{E}utectic {M}ixtures {A}s {H}ighly {C}oncentrated and
{M}olten {E}lectrolytes with {N}early {S}ingle-{I}on
{C}onducting {B}ehavior},
journal = {Meeting abstracts},
volume = {MA2023-02},
number = {2},
issn = {1091-8213},
address = {Pennington, NJ},
publisher = {Soc.},
reportid = {FZJ-2024-02653},
pages = {199 - 199},
year = {2023},
note = {Hierbei handelt es sich lediglich um einen Abstract.},
abstract = {Today's state-of-the-art liquid electrolytes in lithium ion
batteries (LIBs) have a high ionic conductivity and good
performance regarding their cycle life. (1) However, they
pose a safety risk due to their high vapor pressures and low
thermal stability. (1) Furthermore, due to the limited
electrochemical stability of the solvent, liquid
electrolytes are not suitable for the application in
high-voltage LIBs. (2) Molten salts, also called ionic
liquids (IL), or highly concentrated electrolytes (HCE) have
high lithium ion concentrations, where nearly every solvent
molecule is coordinated. Due to this, there are strong ion
interactions and the formation of ion clusters that lead to
an increased lithium ion transference number of >0.5. (3)
Therefore, they can represent an alternative in the field of
liquid electrolytes. Additionally, HCE exhibit a higher
thermal and electrochemical stability compared to dilute
electrolytes and can improve the cycle performance in
lithium metal batteries. (4, 5)McOwen etal. reported the
coordination of lithium ions and crystalline structures in
HCE of the binary mixtures of ethylene carbonate (EC) and
lithium bis(trifluoromethane sulfonyl)imide (LiTFSI) with
molar ratio up to 1:1. (6) Based on the concept of melting
point depression as known from thermodynamics,
room-temperature molten, highly concentrated electrolytes of
a carbonate-based solvent with lithium sulfonyl imides were
investigated. Instead of EC, the solvent pinacol carbonate
(PIC) without acidic α-hydrogen atoms, but four bulky
methyl groups was synthesized and used for eutectic
mixtures, as the melting point of PIC is with 187 °C far
above room-temperature. The physicochemical properties of
these electrolytes are studied with respect to the different
influence of lithium bis(fluorosulfonyl)imide and LiTFSI
despite their same basic molecule structure. The focus will
be on the electrochemical analysis by the means of the ionic
conductivity, transference number and the electrochemical
stability.In comparison to dilute liquid electrolytes the
molten electrolytes show extremely high transference
numbers, especially for the PIC-LiTFSI mixtures nearly a
single-ion conducting behavior (0.9) is observed. This
behavior can be explained by the formation of a 2D polymeric
network within the HCE electrolyte as determined by
crystallographic measurements in the solid state. Combined
with the high electrochemical stability, a stable long-term
cycling and dendrite suppression in symmetric lithium cells
could be shown. Cycling in full cells with high-voltage
cathode materials such as LiNi0.6Mn0.2Co0.2O2 (NMC622) or
LiMn4O2 (LMO) against lithium metal anodes is
applicable.References K. Xu, Chemical Reviews, 104(10),
4303–4417 (2004). J. Li, C. Ma, M. Chi, C. Liang and N. J.
Dudney, Advanced Energy Materials, 5(4) (2015). K. M.
Diederichsen, E. J. McShane and B. D. McCloskey, ACS ENERGY
LETTERS, 2(11), 2563–2575 (2017). G. Jiang, F. Li, H.
Wang, M. Wu, S. Qi, X. Liu, S. Yang and J. Ma, Small
Struct., 2(5), 2000122 (2021). V. Nilsson, A. Kotronia, M.
Lacey, K. Edstrom and P. Johansson, ACS Applied Energy
Materials, 3(1), 200–207 (2020). D. W. McOwen, D. M. Seo,
O. Borodin, J. Vatamanu, P. D. Boyle and W. A. Henderson,
Energy $\&$ Environmental science, 7(1), 416–426 (2014).},
cin = {IEK-12},
ddc = {540},
cid = {I:(DE-Juel1)IEK-12-20141217},
pnm = {1221 - Fundamentals and Materials (POF4-122)},
pid = {G:(DE-HGF)POF4-1221},
typ = {PUB:(DE-HGF)16},
doi = {10.1149/MA2023-022199mtgabs},
url = {https://juser.fz-juelich.de/record/1025065},
}