Non-aqueous electrolyte and secondary battery using the same
View Patent ↗Disclosed is an electrolyte for a secondary battery comprising an electrolyte salt and an electrolyte solvent, the electrolyte further comprising both a cyclic diester compound and a sulfinyl group-containing compound. Also, disclosed is an electrode having a solid electrolyte interface (SEI) film partially or totally formed on a surface thereof, the SEI film being formed by electrical reduction of the above compounds. Further, a secondary battery comprising the electrolyte and/or the electrode is disclosed.
1. An electrolyte for a secondary battery comprising an electrolyte salt and an electrolyte solvent, the electrolyte further comprising both a cyclic diester compound and a sulfinyl group-containing compound, wherein the cyclic diester compound is not lactide.
2. The electrolyte for a secondary battery as claimed in claim 1 , wherein the cyclic diester compound and the sulfinyl group-containing compound have the difference tolerance of 0 to 0.5V in reduction potentials vs. Li+/Li.
3. The electrolyte for a secondary battery as claimed in claim 1 , wherein the cyclic diester compound and the sulfinyl group-containing compound have the difference tolerance of 0 to 0.3V in reduction potentials vs. Li+/Li.
4. The electrolyte for a secondary battery as claimed in claim 1 , wherein the cyclic diester compound is represented by the following Formula 1:
wherein each of R 1 ˜R 4 independently represents a hydrogen atom, halogen atom, C1˜C10 alkyl group, C2˜C10 alkenyl group, or a halogen-substituted alkyl, or alkenyl group, wherein the cyclic diester compound is not lactide.
5. The electrolyte for a secondary battery as claimed in claim 1 , wherein the cyclic diester compound is selected from the group consisting of glycolide, methyl glycolide, tetramethyl glycolide, fluoroglycolide and vinyl glycolide.
6. The electrolyte for a secondary battery as claimed in claim 1 , wherein the sulfinyl group-containing compound is selected from the group consisting of sulfone, sulfite, sulfonate and sultone.
7. The electrolyte for a secondary battery as claimed in claim 1 , wherein the sulfinyl group-containing compound is selected from the group consisting of the compounds represented by the following Formula 2, Formula 3 and Formula 4:
wherein each of R 1 and R 2 independently represents a hydrogen atom, halogen atom, C1˜C10 alkyl group, C2˜C10 alkenyl group, or a halogen-substituted alkyl or alkenyl group.
8. The electrolyte for a secondary battery as claimed in claim 1 , wherein the sulfinyl group-containing compound is selected from the group consisting of divinyl sulfone, ethylene sulfite, propylene sulfite, diallyl sulfonate, propane sultone, butane sultone and propene sultone.
9. The electrolyte for a secondary battery as claimed in claim 1 , wherein the cyclic diester compound is used in an amount of 0.1˜10 parts by weight per 100 parts by weight of the electrolyte, and the sulfinyl group-containing compound is used in an amount of 0.5˜5 parts by weight per 100 parts by weight of the electrolyte.