Non-aqueous electrolyte solvents for secondary cells

An electrolyte element for use in an electric current producing cell, said electrolyte element comprising:

• (i) one or more ionic electrolyte salts;
• and,
• (ii) a non-aqueous electrolyte solvent, which solvent comprises one or more fluorinated, non-symmetrical, non-cyclic sulfones of the general formula:
• R1—SO2—R2
• wherein:
• R1 is a linear or branched partially or fully fluorinated alkyl group are having 1 to 7 carbon atoms;
• R2 is a linear or branched alkyl or partially or fully fluorinated linear or branched alkyl group are having 1 to 7 carbon atoms;
• and,
• R1 and R2 are different.

An electric current producing cell comprising:

• (a) a cathode;
• (b) an anode;
• and,
• (c) a non-aqueous electrolyte element, wherein said electrolyte element comprises:
• (i) one or more ionic electrolyte salts;
• and,
• (ii) a non-aqueous electrolyte solvent, which solvent comprises one or more non-symmetrical, non-cyclic sulfones of the general formula:
• R1—SO2—R2
• wherein:
• R1 and R2 are independently linear or branched alkyl or partially or fully fluorinated linear or branched alkyl groups having 1 to 7 carbon atoms, and R1 and R2 are different;
• wherein said electrolyte element is interposed between said cathode and said anode.