An electrolyte for a lithium secondary battery according to exemplary embodiments of the present inventing includes an organic solvent, a lithium salt, a first additive represented by a predetermined chemical formula, and a second additive represented by a predetermined chemical formula. A protective film is formed by the additives to suppress an expansion of a lithium secondary battery and improve storage property at high temperature.

A 1,4-dioxane solvate of lithium difluoro bis(oxalato)phosphate, a method for preparing the same, and an electrolyte composition containing the same are disclosed. The 1,4-dioxane solvate of lithium difluorobis(oxalato)phosphate has excellent crystallinity and filterability, so that a compound with high purity can be obtained in high yield. Further, since it has excellent stability against moisture, its distribution and storage are easy and the stability of the composition containing 1,4-dioxane solvate of lithium difluoro bis(oxalato)phosphate can be greatly improved.

A 1,4-dioxane solvate of lithium difluoro bis(oxalato)phosphate, a method for preparing the same, and an electrolyte composition containing the same are disclosed. The 1,4-dioxane solvate of lithium difluorobis(oxalato)phosphate has excellent crystallinity and filterability, so that a compound with high purity can be obtained in high yield. Further, since it has excellent stability against moisture, its distribution and storage are easy and the stability of the composition containing 1,4-dioxane solvate of lithium difluoro bis(oxalato)phosphate can be greatly improved.