  Lithium salts with low coordinating anions like
bis(trifluoromethanesulfonyl)imide (TFSI) have been the state-of-the-art for
PEO-based 'dry' polymer electrolytes for three 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' counterpart and
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 higher Li$^+$
transference number. The Li-TFSAM interaction in binary and ternary TFSAM-based
electrolytes was probed by experimental methods and discussed in the context of
recent computational results. In PEO-based TSPEs, TFSAM drastically accelerates
the Li$^+$ transport (increased Li$^+$ transference number by 600$\%$ and
Li$^+$ conductivity by 200-300$\%$) and computer simulations reveal that
lithium dynamics are effectively re-coupled from polymer to anion dynamics.
Finally, this concept of coordinating anions in TSPEs was successfully applied
in LFP$||$Li metal cells leading to enhanced capacity retention (86$\%$ after
300 cycles) and an improved rate performance at 2C.
