%0 Journal Article
%A Hoffknecht, Jan-Philipp
%A Wettstein, Alina
%A Atik, Jaschar
%A Krause, Christian
%A Thienenkamp, Johannes
%A Brunklaus, Gunther
%A Winter, Martin
%A Diddens, Diddo
%A Heuer, Andreas
%A Paillard, Elie
%T Coordinating Anions “to the Rescue” of the Lithium Ion Mobility in Ternary Solid Polymer Electrolytes Plasticized With Ionic Liquids
%J Advanced energy materials
%V 13
%N 1
%@ 1614-6832
%C Weinheim
%I Wiley-VCH
%M FZJ-2023-01300
%P 2202789 -
%D 2023
%X Lithium salts with low coordinating anions such as bis(trifluoromethanesulfonyl)imide (TFSI) have been the state-of-the-art for polyethylene oxide (PEO)-based “dry” polymer electrolytes for 3 decades. Plasticizing PEO with TFSI-based ionic liquids (ILs) to form ternary solid polymer electrolytes (TSPEs) increases conductivity and Li+ diffusivity. However, the Li+ transport mechanism is unaffected compared to their “dry” counterparts and is essentially coupled to the dynamics of the polymer host matrix, which limits Li+ transport improvement. Thus, a paradigm shift is hereby suggested: the utilization of more coordinating anions such as trifluoromethanesulfonyl-N-cyanoamide (TFSAM), able to compete with PEO for Li+ solvation, to accelerate the Li+ transport and reach a higher Li+ transference number. The Li–TFSAM interaction in binary and ternary TFSAM-based electrolytes is probed by experimental methods and discussed in the context of recent computational results. In PEO-based TSPEs, TFSAM drastically accelerates the Li+ transport (increases Li+ transference number by a factor 6 and the Li+ conductivity by 2–3) and computer simulations reveal that lithium dynamics are effectively re-coupled from polymer to anion dynamics. Last, this concept of coordinating anions in TSPEs is successfully applied in LFP||Li metal cells leading to enhanced capacity retention (86% after 300 cycles) and an improved rate performance at 2C.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000888918600001
%R 10.1002/aenm.202202789
%U https://juser.fz-juelich.de/record/1005101