Non-aqueous electrolyte secondary battery and non-aqueous electrolyte
View Patent ↗A non-aqueous electrolyte secondary battery including a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and a non-aqueous electrolyte. The non-aqueous electrolyte contains a lithium salt and a carboxylic acid, and the lithium salt includes lithium difluorophosphate. The content of the carboxylic acid in the non-aqueous electrolyte is 5 ppm or more and 900 ppm or less with respect to the mass of the non-aqueous electrolyte.
1. A non-aqueous electrolyte secondary battery, comprising:
a positive electrode; a negative electrode; a separator interposed between the positive electrode and the negative electrode; and a non-aqueous electrolyte, wherein
the non-aqueous electrolyte contains a lithium salt and a carboxylic acid,
the lithium salt includes lithium difluorophosphate, and
a content of the carboxylic acid in the non-aqueous electrolyte is 5 ppm or more and 900 ppm or less with respect to a mass of the non-aqueous electrolyte.
2. The non-aqueous electrolyte secondary battery according to claim 1 , wherein the carboxylic acid includes at least one kind selected from the group consisting of monocarboxylic acids having two to four carbon atoms.
3. The non-aqueous electrolyte secondary battery according to claim 1 , wherein the non-aqueous electrolyte further contains an alcohol.
4. The non-aqueous electrolyte secondary battery of claim 3 , wherein a content of the alcohol in the non-aqueous electrolyte is 900 ppm or less with respect to the mass of the non-aqueous electrolyte.
5. The non-aqueous electrolyte secondary battery according to claim 3 , wherein the alcohol includes methanol.
6. The non-aqueous electrolyte secondary battery according to claim 1 , wherein a content of the lithium salt in the non-aqueous electrolyte is 1 mol/liter or more and 2 mol/liter or less.
7. The non-aqueous electrolyte secondary battery according to claim 1 , wherein the lithium salt further includes lithium bis(fluorosulfonyl)imide.
8. A non-aqueous electrolyte, comprising:
a lithium salt; and a carboxylic acid, wherein
the lithium salt includes lithium difluorophosphate, and
a content of the carboxylic acid is 5 ppm or more and 900 ppm or less in terms of a mass ratio.
9. The non-aqueous electrolyte according to claim 8 , wherein the carboxylic acid includes at least one kind selected from the group consisting of monocarboxylic acids having two to four carbon atoms.
10. The non-aqueous electrolyte according to claim 8 , further comprising an alcohol.
11. The non-aqueous electrolyte according to claim 10 , wherein a content of the alcohol is 900 ppm or less in terms of a mass ratio.
12. The non-aqueous electrolyte according to claim 10 , wherein the alcohol includes methanol.
13. The non-aqueous electrolyte according to claim 8 , wherein a content of the lithium salt is 1 mol/liter or more and 2 mol/liter or less.
14. The non-aqueous electrolyte according to claim 8 , wherein the lithium salt further includes lithium bis(fluorosulfonyl)imide.