Non-aqueous electrolyte and lithium secondary battery including the same
View Patent ↗Provided are a non-aqueous electrolyte including a non-aqueous organic solvent, a lithium salt, and a borate-based compound, and a lithium secondary battery using the same. According to the present invention, a lithium secondary battery having improved cycle characteristics and high-temperature storage stability may be prepared by including a non-aqueous electrolyte which includes at least one borate-based compound as an additive.
1. A non-aqueous electrolyte comprising:
a non-aqueous organic solvent;
a lithium salt;
a borate-based compound represented by Chemical Formula 1;
where R 1 to R 4 are each independently a halogen or a halogen-substituted alkyl having 1 to 3 carbon atoms; and
at least one borate-based compound comprising Chemical Formula 2:
and at least one borate-based compound comprising Chemical Formula 3
where R 5 to R 12 are each independently hydrogen, an alkyl having 1 to 3 carbon atoms, a halogen, or a halogen-substituted alkyl having 1 to 3 carbon atoms.
2. The non-aqueous electrolyte of claim 1 , wherein the borate-based compound of Chemical Formula 1 is represented by Chemical Formula 1a:
3. The non-aqueous electrolyte of claim 1 , wherein the borate-based compound of Chemical Formula 3 is represented by Chemical Formula 3a:
4. The non-aqueous electrolyte of claim 1 , wherein the borate-based compound of Chemical Formula 1 is included in an amount of 0.1 wt % to 20 wt % based on a total weight of the non-aqueous electrolyte.
5. The non-aqueous electrolyte of claim 1 , wherein a weight ratio of the borate-based compound of Chemical Formula 1 and the borate-based compound selected from either Chemical Formula 2 or Chemical Formula 3 is 1:0.2 to 1:2.0.
6. The non-aqueous electrolyte of claim 1 , wherein the non-aqueous electrolyte comprises the borate-based compound of Chemical Formula 1, the borate-based compound of Chemical Formula 2, and the borate-based compound of Chemical Formula 3 in a weight ratio of 1:0.2:0.2 to 1:1.0:1.0.
7. The non-aqueous electrolyte of claim 1 , wherein the non-aqueous organic solvent comprises one selected from the group consisting of a cyclic carbonate solvent, a linear carbonate solvent, an ester solvent, and a ketone solvent, or a mixed solution of two or more thereof.
8. The non-aqueous electrolyte of claim 7 , wherein the cyclic carbonate solvent comprises one selected from ethylene carbonate, propylene carbonate, butylene carbonate, or a mixed solution of two or more thereof.
9. The non-aqueous electrolyte of claim 7 , wherein the linear carbonate solvent comprises one selected from dimethyl carbonate, diethyl carbonate, dipropyl carbonate, ethylmethyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, or a mixed solution of two or more thereof.
10. The non-aqueous electrolyte of claim 7 , wherein the ester solvent comprises one selected from methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, γ-butyrolactone, γ-valerolactone, or γ-caprolactone, or a mixed solution of two or more thereof.
11. The non-aqueous electrolyte of claim 1 , wherein the lithium salt comprises at least one selected from LiPF 6 , LiAsF 6 , LiN(CF 3 SO 2 ) 2 , LiBF 4 , LiSbF 6 , LiN(C 2 F 5 SO 2 ) 2 , LiAlO 4 , LiAlCl 4 , LiSO 3 CF 3 , or LiClO 4 .
12. A lithium secondary battery comprising:
a cathode;
an anode;
a separator disposed between the cathode and the anode; and
the non-aqueous electrolyte of claim 1 .
13. The lithium secondary battery of claim 12 , wherein the lithium secondary battery is a lithium ion secondary battery or a lithium polymer secondary battery.