Eutectic mixtures containing alkali-metal sulfonimide salts, and electrochemical devices utilizing same

An electrolyte, comprising:

• a substantially eutectic mixture that includes a first salt, X1+Y1−, and a second salt, X2+Y2−, wherein:
• each of X1+ and X2+ is an alkali metal cation and X1+ is different from X2+;
• each of Y1− and Y2− is a sulfonimide anion and Y1− is different from Y2−;
• the substantially eutectic mixture has a melting temperature and a viscosity, and the electrolyte further comprises a fluorine-containing additive that lowers the melting temperature and lowers the viscosity;
• and
• the viscosity is in a range of about 1 cP to about 50 cP.

An electrolyte, comprising:

• a substantially eutectic mixture that includes a first salt, X1+Y1−, and a second salt, X2+Y2−, wherein:
• each of X1+ and X2+ is an alkali metal cation and X1+ is different from X2+;
• each of Y1− and Y2− is a sulfonimide anion and Y1− is different from Y2−;
• and
• the substantially eutectic mixture has a melting temperature in a range of about 5° C. to about 30° C.