Electrolyte solution for secondary battery and secondary battery
An electrolyte for a secondary battery, the electrolyte including: an organic solvent; and a lithium ion conductive solid electrolyte represented by the formula Li a P b S c wherein 3<a<5, 1<b<3, and 6<c<8, and wherein at least a portion of the solid electrolyte is dissolved in the organic solvent.
1. An electrolyte for a secondary battery, the electrolyte comprising:
an organic solvent; and
a lithium ion conductive solid electrolyte represented by the formula
Li a P b S c
wherein 3<a<5, 1<b<3, and 6<c<8, and
wherein at least a portion of the solid electrolyte is dissolved in the organic solvent.
2. The electrolyte of claim 1 , wherein the at least a portion of the solid electrolyte has a composition of the formula Li 4 P 2 S 7 .
3. The electrolyte of claim 1 , wherein the electrolyte has a lithium ion conductivity of 1×10 −6 Siemens per centimeter or greater.
4. The electrolyte of claim 1 , wherein a concentration of the solid electrolyte dissolved in the organic solvent is 0.005 molar or greater.
5. The electrolyte of claim 1 , wherein the solvent comprises at least one selected from an ether and an ester.
6. The electrolyte of claim 1 , wherein the solvent comprises at least one selected from tetrahydrofuran, glyme, diglyme, triglyme, tetraglyme, diethyl carbonate, propylene carbonate, γ-butyrolactone, and dioxolane.
7. The electrolyte of claim 1 , wherein the electrolyte is in the form of gel.
8. The electrolyte of claim 7 , wherein the gel comprises at least one selected from polyethylene oxide, polyacrylonitrile, polyvinylidene fluoride, and polymethyl methacrylate.
9. The electrolyte of claim 1 , wherein an electrochemical potential window of the electrolyte is from 0 volts to 3.4 volts with respect to lithium metal.
10. A secondary battery comprising:
a negative electrode comprising a material capable of intercalating and deintercalating lithium ions;
a positive electrode comprising a positive electrode active material;
a separator disposed between the negative electrode and the positive electrode; and
an electrolyte disposed between the negative electrode and the positive electrode,
wherein the electrolyte comprises
an organic solvent, and
a lithium ion conductive solid electrolyte represented by the formula
Li a P b S c
wherein 3<a<5, 1<b<3, and 6<c<8, and
wherein at least a portion of the solid electrolyte is dissolved in the organic solvent.
11. The secondary battery of claim 10 , wherein the organic solvent comprises tetrahydrofuran.
12. The secondary battery of claim 10 , wherein the electrolyte further comprises an additive.
13. The secondary battery of claim 12 , wherein the additive comprises at least one selected from an inorganic additive and an organic additive.
14. The secondary battery of claim 12 , wherein the additive comprises at least one selected from LiNO 3 , an alkali metal salt comprising halogen, an alkaline earth metal salt comprising halogen, and an ammonium salt comprising halogen.
15. The secondary battery of claim 12 ,
wherein the positive electrode comprises a positive electrode active material, and
wherein the positive electrode active material comprises sulfur, a lithium metal oxide, or air.
16. The secondary battery of claim 15 , wherein the positive electrode active material comprises sulfur modified with an organic component.
17. The secondary battery of claim 12 , wherein an operating potential of the secondary battery is 3.4 volts or less with respect to a lithium metal.
18. The secondary battery of claim 12 , wherein the positive electrode comprises an olivine positive electrode active material.
19. The secondary battery of claim 18 , wherein the olivine positive electrode active material is represented by Formula 1:
Li x Me y M z PO 4-d X d Formula 1
wherein 0.9≤x≤1.1, 0.9≤y≤1.1, 0≤z≤0.2, and 0≤d≤0.2;
Me is at least one selected from Fe, Mn, Ni, and Co;
M is at least one selected from Mg, Ca, Sr, Ba, Ti, Zr, Nb, Mo, W, Zn, Al, and Si; and
X is at least one selected from S and F.
20. The secondary battery of claim 18 , wherein the olivine positive electrode active material comprises at least one selected from LiFePO 4 , LiFe 1−a Mn a PO 4 wherein 0<a<1, and LiMnPO 4 .