Organic electrolytic solution and lithium secondary battery employing the same
An organic electrolytic solution and a lithium secondary battery employing the same, wherein the organic electrolytic solution for a lithium secondary battery includes a polymer adsorbent having an ethylene oxide chain capable of being adsorbed into a lithium metal, a material capable of reacting with lithium to form a lithium alloy, a lithium salt, and an organic solvent. The organic electrolytic solution may be applied to all types of batteries including lithium ion batteries, lithium polymer batteries and lithium metal polymer batteries using a lithium metal for a negative electrode material, and the like. In particular, when the organic electrolytic solution is utilized in a lithium metal polymer battery, it serves to stabilize the lithium metal, and to increase the lithium ionic conductivity, thereby improving the cycle characteristics and charging/discharging efficiency of the battery.
1. An organic electrolytic solution comprising a polymer adsorbent having an ethylene oxide chain capable of being adsorbed into a lithium metal, a material capable of reacting with lithium to form a lithium alloy, a lithium salt, and an organic solvent, wherein the polymer adsorbent is poly(ethylene glycol) dimethyl ether, or a mixture containing the same.
2. The organic electrolytic solution according to claim 1 , wherein the amount of the polymer adsorbent added is within the range of from about 0.1 to about 1 part by weight, based on 100 parts by weight of total organic electrolytic solution used.
3. The organic electrolytic solution according to claim 1 , wherein the weight-average molecular weight of the polymer adsorbent is from about 200 to about 2000.
4. The organic electrolytic solution according to claim 1 , wherein the weight-average molecular weight of the poly(ethylene glycol) dimethyl ether is from about 1000 to about 2000.
5. The organic electrolytic solution according to claim 1 , wherein poly(ethylene glycol) dimethyl ether is used in an amount of about 0.29 parts by weight, and aluminum iodide is used in an amount of about 0.17 parts by weight, based on 100 parts by weight of total organic electrolytic solution used.
6. The organic electrolytic solution according to claim 1 , wherein the organic solvent is at least one solvent selected from the group consisting of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, vinylene carbonate acetone, acetonitrile, N-methyl-2-pyrrolidone (NMP), diglyme(diethylene glycol dimethyl ether: DGM), diethylene glycol diethyl ether, triglyme(triethylene glycol dimethyl ether: TGM), triethylene glycol diethyl ether, 1,3-dioxolanes (DOX), 4,5-dimethyldioxolane, 4,5-diethyldioxolane, 4-methyl-1,3-dioxolane, 4-ethyl-1,3-dioxolane, 2-fluorobenzene, 3-fluorobenzene, 4-fluorobenzene, dimethoxyethane (DME), diethoxyethane, sulfolane (SUL), and mixtures thereof.
7. A lithium secondary battery comprising the organic electrolytic solution claimed in claim 1 .
8. The organic electrolytic solution according to claim 1 , wherein poly(ethylene glycol) dimethyl ether is used in an amount within the range of from about 0.2 to about 1 part by weight, based on 100 parts by weight of total organic electrolytic solution used.
9. An organic electrolytic solution comprising a polymer adsorbent having an ethylene oxide chain capable of being adsorbed into a lithium metal, a material capable of reacting with lithium to form a lithium alloy, a lithium salt, and an organic solvent, wherein the material capable of reacting with lithium to form a lithium alloy is one or more materials selected from the group consisting of aluminum iodide, aluminum phosphate, aluminum sulfate, aluminum triflate, magnesium iodide, magnesium chloride, magnesium bromide, magnesium perchlorate, magnesium hexafluorophosphate, magnesium triflate, and mixtures thereof.
10. The organic electrolytic solution according to claim 9 , wherein the amount of the material capable of reacting with lithium to form a lithium alloy is within the range of from about 0.01 to about 0.3 parts by weight, based on 100 parts by weight of total organic electrolytic solution.
11. The organic electrolytic solution according to claim 9 , wherein aluminum iodide is used in an amount within the range of from about 0.05 to about 0.3 parts by weight, based on 100 parts by weight of total organic electrolytic solution.
12. An organic electrolytic solution comprising a polymer adsorbent having an ethylene oxide chain capable of being adsorbed into a lithium metal, a material capable of reacting with lithium to form a lithium alloy, a lithium salt, and an organic solvent, wherein the lithium salt is at least one compound selected from the group consisting of LiPF 6 , LiBF 4 , LiClO 4 , Li(CF 3 SO 2 ) 2 , LiN(CF 3 SO 2 ) 2 , LiSbF 6 , LiAsF 6 , and mixtures thereof.
13. The organic electrolytic solution according to claim 12 , wherein the concentration of the lithium salt is within the range of from about 0.4 to about 1.5 M.
14. A method of making an organic electrolytic solution comprising a polymer adsorbent having an ethylene oxide chain capable of being adsorbed into a lithium metal, a material capable of reacting with lithium to form a lithium alloy, a lithium salt, and an organic solvent, comprising:
mixing the lithium salt and the solvent to form a mixture; and
adding to the mixture the polymer adsorbent having an ethylene oxide chain capable of being adsorbed into a lithium metal and the material capable of reacting with lithium to form a lithium alloy.
15. The method according to claim 14 , wherein the polymer adsorbent is one or more polymers selected from the group consisting of poly(ethylene)oxide, poly(ethylene glycol) monomethyl ether, poly(ethylene glycol) dimethyl ether, poly(ethylene glycol) monomethyl acrylate, poly(ethylene glycol) dimethyl acrylate, and mixtures thereof.
16. The method according to claim 14 , wherein the material capable of reacting with lithium to form a lithium alloy is one or more materials selected from the group consisting of aluminum iodide, aluminum phosphate, aluminum sulfate, aluminum triflate, magnesium iodide, magnesium chloride, magnesium bromide, magnesium perchlorate, magnesium hexafluorophosphate, magnesium triflate, and mixtures thereof.
17. The method according to claim 14 , wherein the lithium salt is at least one compound selected from the group consisting of LiPF 6 , LiBF 4 , LiClO 4 , Li(CF 3 SO 2 ) 2 , LiN(CF 3 SO 2 ) 2 , LiSbF 6 , LiAsF 6 , and mixtures thereof.
18. The method according to claim 14 , wherein the organic solvent is at least one solvent selected from the group consisting of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, vinylene carbonate acetone, acetonitrile, N-methyl-2-pyrrolidone (NMP), diglyme(diethylene glycol dimethyl ether: DGM), diethylene glycol diethyl ether, triglyme(triethylene glycol dimethyl ether: TGM), triethylene glycol diethyl ether, 1,3-dioxolanes (DOX), 4,5-dimethyldioxolane, 4,5-diethyldioxolane, 4-methyl-1,3-dioxolane, 4-ethyl-1,3-dioxolane, 2-fluorobenzene, 3-fluorobenzene, 4-fluorobenzene, dimethoxyethane (DME), diethoxyethane, sulfolane (SUL), and mixtures thereof.
19. The method according to claim 14 , wherein polyethylene glycol dimethyl ether is used in an amount of about 0.29 parts by weight, and aluminum iodide is used in an amount of 0.17 parts by weight, based on 100 parts by weight of total organic electrolytic solution used.
20. A lithium secondary battery comprising an organic electrolytic solution,
wherein the organic electrolytic solution includes a polymer adsorbent having an ethylene oxide chain, a lithium salt, and an organic solvent, and the polymer adsorbent is poly(ethylene glycol) dimethyl ether or a mixture containing the same,
the battery further including a lithium negative electrode having a lithium alloy on a surface of the electrode.