Nonaqueous electrolytic solution and nonaqueous-electrolyte secondary battery

A nonaqueous electrolytic solution which comprises:

• a nonaqueous solvent;
• LiPF6;
• and a fluorosulfonic acid salt represented by formula
• M(FSO3)x
• wherein
• M is a metal atom, N(R)4, or P(R)4 wherein R is either an organic group having 1-12 carbon atoms or a hydrogen atom wherein not all of the four R's are hydrogen atoms, the R's may be the same or different, and a part or all of the four R's may form a ring in cooperation with the nitrogen atom or phosphorus atom to which the R's have been bonded;
• when M is a metal atom, x indicates the valence of the metal atom M and is an integer of 1 or larger;
• and when M is N(R)4 or P(R)4, x is 1,
• wherein the nonaqueous electrolytic solution further comprises at least one selected from the group consisting of a cyclic carbonate having a fluorine atom, a cyclic carbonate having carbon-carbon unsaturated bond, a cyclic sulfonic acid ester compound, a compound having cyano group, a diisocyanate compound, a fluorophosphoric acid lithium salt other than LiPF6, a lithium imide salt, and a lithium salt having an oxalic acid group.