, then kept at each test temperature for at least half an
hour before electrochemical impedance measurements in order to
reach thermal equilibrium. The electrochemical impedance spectroscopy measurements
were carriedout by applying the frequency
range from 100 kHz to 0.1 Hz at temperatures between −20 and
80 ◦C with oscillation amplitude of 5 mV on a CHI660C Electrochemical
Workstation (Shanghai Chenhua). The electrochemical
stabilities of the electrolytes were studied with cyclic voltammetry
(CV) at a scan rate of 1 mVs−1 in the voltage range of −0.5 to 5V in
a three-electrode system. A stainless steel blocking electrode was
used as the working electrode, while a lithium metal was used as
the reference and the counter electrode in this system.