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FSI − -based ionic liquids (ILs) are promising electrolyte candidates for longlife and safe lithium metal batteries (LMBs). However, their practical application is hindered by sluggish Li + transport at room temperature. Herein, it is shown that additions of bis(2,2,2-trifluoroethyl) ether (BTFE) to LiFSI-Pyr 14 FSI ILs can effectively mitigate this shortcoming, while maintaining ILs′ high compatibility with lithium metal. Raman spectroscopy and small-angle X-ray scattering indicate that the promoted Li + transport in the optimized electrolyte, [LiFSI] 3 [Pyr 14 FSI] 4 [BTFE] 4 (Li 3 Py 4 BT 4 ), originates from the reduced solution viscosity and increased formation of Li + -FSI − complexes, which are associated with the low viscosity and non-coordinating character of BTFE. As a result, Li/LiFePO 4 (LFP) cells using Li 3 Py 4 BT 4 electrolyte reach 150 mAh g −1 at 1 C rate (1 mA cm −2 ) and a capacity retention of 94.6% after 400 cycles, revealing better characteristics with respect to the cells employing the LiFSI-Pyr 14 FSI (operate only a few cycles) and commercial carbonate (80% retention after only 218 cycles) electrolytes. A wide operating temperature (from −10 to 40 °C) of the Li/Li 3 Py 4 BT 4 /LFP cells and a good compatibility of Li 3 Py 4 BT 4 with LiNi 0.5 Mn 0.3 Co 0.2 O 2 (NMC532) are demonstrated also. The insight into the enhanced Li + transport and solid electrolyte interphase characteristics suggests valuable information to develop IL-based electrolytes for LMBs.The ORCID identification number(s) for the author(s) of this article can be found under

Almost all the traditional ionic liquids lack liquid crystal properties.

Ordered ion channels were constructed using liquid crystal, while ionic liquid was inserted into the channels for fast transport ions.