Non-aqueous electrolyte for secondary battery and non-aqueous electrolyte secondary battery

A non-aqueous electrolyte secondary battery comprising a positive electrode, a negative electrode, a separator, and a non-aqueous electrolyte,

• wherein said non-aqueous electrolyte comprises a non-aqueous solvent dissolving lithium salt as an electrolyte;
• wherein said non-aqueous solvent contains:
• (A) methyl 3,3,3-trifluoropropionate represented by the below formula (1);
• CF3—CH2—COO—CH3 (1)
• and
• (B) a film-forming chemical compound decomposed in the range of +1.0 to 3.0 V based on an equilibrium potential between metal lithium and lithium ion;
• wherein said film-forming chemical compound is at least one selected from a group consisting of 4-fluoroethylene carbonate, ethylene sulfite, vinyl ethylene carbonate, LiB(C2O4)2, and LiBF2(C2O4);
• and
• wherein said non-aqueous solvent further contains at least one low viscosity solvent selected from a group of CH3COOCH3, C2H5COOCH3, CH3COOC2H5, and CH3OCOOCH3;
• wherein the amount of said methyl 3,3,3-trifluoropropionate is in the range of 20 to 90 volume % to the whole amount of non-aqueous solvent and
• wherein the amount of said 4-fluoroethylene carbonate to the whole amount of non-aqueous solvent is 2-40 volume %, the amount of said ethylene sulfite and said vinyl ethylene carbonate to the whole amount of non-aqueous solvent is 0.1-10 wt %, and the amount of said LiB(C2O4)2 and said LiBF2(C2O4) to the whole amount of non-aqueous solvent is 0.01-0.4 mol/l.

A non-aqueous electrolyte for secondary battery comprising a non-aqueous solvent dissolving lithium salt as an electrolyte,

• wherein said non-aqueous solvent contains:
• (A) methyl 3,3,3-trifluoropropionate represented by the below formula (1);
• CF3—CH2—COO—CH3 (1)
• and
• (B) a film-forming chemical compound decomposed in the range of +1.0 to 3.0 V based on an equilibrium potential between metal lithium and lithium ion;
• wherein said film-forming chemical compound is at least one selected from the group consisting of 4-fluoroethylene carbonate, ethylene sulfite, vinyl ethylene carbonate, LiB(C2O4)2, and LiBF2(C2O4);
• and
• wherein the amount of said methyl 3,3,3-trifluoropropionate is in the range of 20 to 90 volume % to the whole amount of the non-aqueous solvent;
• and
• wherein the amount of said 4-fluoroethylene carbonate to the whole amount of non-aqueous solvent is 2-40 volume %, the amount of said ethylene sulfite and said vinyl ethylene carbonate to the whole amount of non-aqueous solvent is 0.1-10 wt %, and the amount of said LiB(C2O4)2 and said LiBF2(C2O4) to the whole amount of non-aqueous solvent is 0.01-0.4 mol/l.

A non-aqueous electrolyte secondary battery comprising a positive electrode, a negative electrode, a separator, and a non-aqueous electrolyte,

• wherein said non-aqueous electrolyte comprises a non-aqueous solvent dissolving lithium salt as an electrolyte;
• wherein said non-aqueous solvent contains:
• (A) methyl 3,3,3-trifluoropropionate represented by the below formula (1);
• CF3—CH2—COO—CH3 (1)
• and
• (B) a film-forming chemical compound decomposed in the range of +1.0 to 3.0 V based on an equilibrium potential between metal lithium and lithium ion;
• wherein said film-forming chemical compound is at least one selected from a group consisting of 4-fluoroethylene carbonate, ethylene sulfite, vinyl ethylene carbonate, LiB(C2O4)2, and LiBF2(C2O4);
• and
• wherein the amount of said methyl 3,3,3-trifluoropropionate is in the range of 20 to 90 volume % to the whole amount of the non-aqueous solvent;
• and
• wherein the amount of said 4-fluoroethylene carbonate to the whole amount of non-aqueous solvent is 2-40 volume %, the amount of said ethylene sulfite and said vinyl ethylene carbonate to the whole amount of non-aqueous solvent is 0.1-10 wt %, and the amount of said LiB(C2O4)2 and said LiBF2(C2O4) to the whole amount of non-aqueous solvent is 0.01-0.4 mol/l.