Patent ID: 11961964
Assignee: SOPHIA SCHOOL CORPORATION
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  Y | IPC H

Claim 8:
9. A lithium-ion secondary battery comprising at least a positive electrode, a negative electrode, and an electrolyte solution,
the negative electrode including at least a negative electrode active material and a solid electrolyte interface (SEI) film, the SEI film being formed on a surface of the negative electrode active material, the film containing a lithium compound,
the electrolyte solution containing at least a solvent, a lithium salt, and a zwitterionic compound, the solvent not containing a salt,
the zwitterionic compound containing a phosphonium cation and a carboxylate anion in one molecule,
an amount of the zwitterionic compound in the electrolyte solution is 0.01 to 0.1 mol/L.