Electrolyte and rechargeable lithium battery including the same
An electrolyte for a rechargeable lithium battery, the electrolyte including a lithium salt, a non-aqueous organic solvent, a first additive represented by Chemical Formula 1, and a second additive represented by Chemical Formula 2 is disclosed. A rechargeable lithium battery including the electrolyte is also disclosed. The structures and definitions of the Chemical Formulae 1 and 2 are the same as described in the detailed description.
1. An electrolyte for a rechargeable lithium battery, comprising:
a lithium salt;
a non-aqueous organic solvent;
a first additive comprising a first compound represented by Chemical Formula 1:
wherein,
A is boron (B) or phosphorus (P),
X is a halogen element,
n is an integer ranging from 0 to 2,
m is an integer ranging from 1 to 3,
when A is boron (B), n+m=2, and
when A is phosphorus (P), n+m=3; and
a second additive comprising a second compound represented by Chemical Formula 2:
wherein Y is a halogen element, and
wherein the first additive and the second additive are each included in the electrolyte in an amount in a range of about 0.5 wt % to about 1.5 wt %, based on the total amount of the electrolyte.
2. The electrolyte of claim 1 , wherein the first compound is represented by one of Chemical Formulae 1a to 1e:
3. The electrolyte of claim 1 , wherein the second compound is represented by Chemical Formula 2a:
4. The electrolyte of claim 1 , wherein the first additive and the second additive are included in the electrolyte in a weight ratio in a range of about 1:0.5 to about 1:1.5.
5. The electrolyte of claim 1 , wherein the first compound is represented by Chemical Formula 1d:
and
the second compound is represented by Chemical Formula 2a:
6. The electrolyte of claim 1 , wherein the non-aqueous organic solvent comprises ethylene carbonate (EC), ethylmethyl carbonate (EMC), and dimethyl carbonate (DMC), and
the ethylene carbonate (EC) is included in the non-aqueous organic solvent in an amount of greater than or equal to about 20 wt %, based on the total amount of the non-aqueous organic solvent.
7. A rechargeable lithium battery, comprising:
a positive electrode comprising a positive active material layer;
a negative electrode comprising a negative active material layer; and
the electrolyte according to claim 1 .
8. The rechargeable lithium battery of claim 7 , wherein the positive active material layer comprises lithium intercalation compound and activated carbon.
9. The rechargeable lithium battery of claim 8 , wherein the activated carbon is included in the positive active material layer in an amount in a range of about 0.01 wt % to about 20 wt %, based on the total amount of the lithium intercalation compound and the activated carbon.
10. The rechargeable lithium battery of claim 8 , wherein the negative active material layer comprises soft carbon.
11. The rechargeable lithium battery of claim 7 , wherein the first additive and the second additive are impregnated at a concentration in a range of about 0.005 wt % to about 2 wt % based on the amount of the electrolyte, in at least one of the positive electrode and the negative electrode.
12. The rechargeable lithium battery of claim 7 , wherein the negative electrode further comprises a solid electrolyte interface (SEI) film on the surface of the negative electrode.