Non-aqueous electrolyte secondary battery, electrolyte solution, and method for producing non-aqueous electrolyte secondary battery

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 an electrolyte solution,
• wherein the electrolyte solution includes a solvent and a solute,
• the solvent includes a carboxylic acid ester compound,
• the solute includes a sulfonyl imide compound,
• the negative electrode includes a coating derived from a sulfonyl imide compound and a carboxylic anhydride,
• a proportion of the carboxylic acid ester compound in the solvent is 5 vol % to 20 vol %,
• the sulfonyl imide compound includes lithium bis(fluorosulfonyl)imide:
• LiN(SO2F)2, and
• the negative electrode includes a composite material including a lithium silicate phase and silicon particles dispersed in the lithium silicate phase.

A method for producing a non-aqueous electrolyte secondary battery, comprising the steps of:

• assembling an uncharged battery including a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and an electrolyte solution,
• wherein the electrolyte solution comprises:
• a solvent, a solute, and a carboxylic anhydride,
• wherein the solvent includes a carboxylic acid ester compound,
• the solute includes a sulfonyl imide compound,
• a proportion of the carboxylic acid ester compound in the solvent is 5 vol % to 20 vol %,
• the sulfonyl imide compound includes lithium bis(fluorosulfonyl)imide:
• LiN(SO2F)2, and
• the negative electrode includes a composite material including a lithium silicate phase and silicon particles dispersed in the lithium silicate phase.