IPC분류정보
국가/구분 |
United States(US) Patent
등록
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국제특허분류(IPC7판) |
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출원번호 |
US-0859558
(2001-05-17)
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발명자
/ 주소 |
- Gan, Hong
- Smesko, Sally Ann
- Takeuchi, Esther S.
- Davis, Steven M.
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출원인 / 주소 |
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대리인 / 주소 |
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인용정보 |
피인용 횟수 :
14 인용 특허 :
18 |
초록
▼
The minimization or elimination of swelling in lithium cells containing CF x as part of the cathode electrode and discharged under high rate applications is described. When CF x materials are synthesized from fibrous carbonaceous materials, in comparison to petroleum coke, cell swelling is greatly
The minimization or elimination of swelling in lithium cells containing CF x as part of the cathode electrode and discharged under high rate applications is described. When CF x materials are synthesized from fibrous carbonaceous materials, in comparison to petroleum coke, cell swelling is greatly reduced, and in some cases eliminated. Preferred precursors are carbon fibers and MCMB.
대표청구항
▼
1. An electrochemical cell, which comprises:a) an anode;b) a cathode of a first fluorinated carbon of a first energy density and a first rate capability and a second cathode active material of a second energy density and a second rate capability, wherein the first energy density of the first fluorin
1. An electrochemical cell, which comprises:a) an anode;b) a cathode of a first fluorinated carbon of a first energy density and a first rate capability and a second cathode active material of a second energy density and a second rate capability, wherein the first energy density of the first fluorinated carbon is greater than the second energy density while the first rate capability is less than the second rate capability of the second cathode active material;c) a cathode current collector comprising spaced apart major sides with the first fluorinated carbon positioned proximate one of the major sides and the second cathode active material proximate the other major side; andd) an electrolyte comprising at least one solvent for activating the anode and the cathode, wherein the fluorinated carbon is characterized as having been synthesized from a fibrous carbonaceous material having sufficient spacing between graphite layers to substantially restrict expansion due to solvent co-intercalation. 2. The electrochemical cell of claim 1 wherein the cell is dischargeable at a current pulse of at least about 15.0 mA/cm 2 . 3. The electrochemical cell of claim 1 wherein the fluorinated carbon synthesized from the fibrous carbonaceous material has a BET surface area of greater than about 250 m 2 /g. 4. The electrochemical cell of claim 1 wherein the fluorinated carbon synthesized from the fibrous carbonaceous material has a particle size volume percent of less than about 15 μm. 5. The electrochemical cell of claim 1 wherein the fluorinated carbon synthesized from the fibrous carbonaceous material has a particle size surface area percent of less than about 3.5. 6. The electrochemical cell of claim 1 wherein the fluorinated carbon synthesized from the fibrous carbonaceous material has a DTA exotherm of about 652° C. to about 656° C. 7. The electrochemical cell of claim 1 wherein the carbonaceous material is selected from the group consisting of carbon fibers with an annual ring layered structure having graphite crystallite edges exposed only on the cross-section, carbon fibers with a radial layered structure having the entire fiber surface with exposed graphite crystallite edges, and mesophase carbon microbeads with a radial-like texture having the entire surface of the microbead with exposed graphite crystallite edges. 8. The electrochemical cell of claim 1 wherein the second cathode active material is selected from the group consisting of silver vanadium oxide, copper silver vanadium oxide, V 2 O 5 , MnO 2 , LiCoO 2 , LiNiO 2 , LiMnO 2 , CuO, TiS, CuS, FeS, FeS 2 , copper vanadium oxide, and mixtures thereof. 9. The electrochemical cell of claim 1 wherein the cathode has the configuration: SVO/current collector/CF x /current collector/SVO. 10. The electrochemical cell of claim 1 wherein the cathode has the configuration: SVO/current collector/SVO/CF x /SVO/current collector/SVO. 11. The electrochemical cell of claim 1 wherein the anode is lithium and the cathode has the configuration: SVO/current collector/CF x , with the SVO facing the lithium anode. 12. The electrochemical cell of claim 1 wherein the first cathode active material is sandwiched between a first and second current collectors with the second cathode active material contacting the first and second current collectors opposite the first cathode active material. 13. The electrochemical cell of claim 12 wherein the first and second current collectors are titanium having a coating selected from the group consisting of graphite/carbon material, iridium, iridium oxide and platinum provided thereon. 14. The electrochemical cell of claim 1 wherein the anode is lithium, the first cathode active material is CF x , the second cathode active material is SVO and the cathode current collector is titanium or aluminum. 15. The electrochemical cell of claim 1 wherein the electrolyte has a first solvent selected from an ester, a linear ether, a cyclic ether, a dia lkyl carbonate, and mixtures thereof, and a second solvent selected from a cyclic carbonate, a cyclic ester, a cyclic amide, and mixtures thereof. 16. The electrochemical cell of claim 15 wherein the first solvent is selected from the group consisting of tetrahydrofuran, methyl acetate, diglyme, trigylme, tetragylme, dimethyl carbonate, 1,2-dimethoxyethane, 1,2-diethoxyethane, 1-ethoxy, 2-methoxyethane, ethyl methyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, diethyl carbonate, dipropyl carbonate, and mixtures thereof, and the second solvent is selected from the group consisting of propylene carbonate, ethylene carbonate, butylene carbonate, acetonitrile, dimethyl sulfoxide, dimethyl formamide, dimethyl acetamide, γvalerolactone, γbutyrolactone, N methyl-pyrrolidinone, and mixtures thereof. 17. The electrochemical cell of claim 1 including a lithium salt selected from the group consisting of LiPF 6 , LiBF 4 , LiAsF 6 , LiSbF 6 , LiClO 4 , LiO 2 , LiAlCl 4 , LiGaCl 4 , LiC(SO 2 CF 3 ) 3 , LiN(SO 2 CF 3 ) 2 , LiSCN, LiO 3 SCF 3 , LiC 6 F 5 SO 3 , LiO 2 CCF 3 , LiSO 6 F, LiB(C 6 H 5 ) 4 , LiCF 3 SO 3 , and mixtures thereof. 18. The electrochemical cell of claim 1 wherein the electrolyte is 0.8M to 1.5M LiAsF 6 or LiPF 6 dissolved in a 50:50 mixture, by volume, of propylene carbonate and 1,2-dimethoxyethane. 19. An electrochemical cell, which comprises:a) a lithium anode;b) a cathode of a first cathode active material of CF x sandwiched between a first and second current collectors with a second cathode active material selected from the group consisting of SVO, CSVO, V 2 O 5 , MnO 2 , LiCoO 2 , LiNiO 2 , LiMnO 2 , CuO 2 , TiS, Cu 2 S, FeS, FeS 2 , CVO, and mixtures thereof, contacting the first and second current collectors opposite the first cathode active material; andc) an electrolyte comprising at least one solvent for activating the anode and the cathode, wherein the fluorinated carbon is characterized as having been synthesized from a fibrous carbonaceous material having sufficient spacing between graphite layers to substantially restrict expansion due to solvent co-intercalation. 20. The electrochemical cell of claim 19 wherein the current collectors are of titanium. 21. A method for powering an implantable medical device, comprising the steps of:a) providing the medical device;b) providing an electrochemical cell comprising the steps of:i) providing an anode of an alkali metal;ii) providing a cathode of CF x as a first cathode active material of a first energy density and a first rate capability sandwiched between first and second current collectors with a second cathode active material of a second energy density and a second rate capability, wherein the first energy density of the CF x is greater than the second energy density while the first rate capability is less than the second rate capability of the second cathode active material; andiii) activating the anode and cathode with an electrolyte comprising at least one solvent, wherein the fluorinated carbon is characterized as having been synthesized from a fibrous carbonaceous material having sufficient spacing between graphite layers to substantially restrict expansion due to solvent co-intercalation; andc) electrically connecting the electrochemical cell to the medical device. 22. The method of claim 21 including discharging the cell to provide a current pulse of at least about 15.0 mA/cm 2 . 23. The method of claim 21 including providing the fluorinated carbon synthesized from the fibrous carbonaceous material having a BET surface area of greater than about 250 m 2 /g. 24. The method of claim 21 including providing the fluorinated carbon synthesized from the fibrous carbonaceous material having a particle size volume percent of less than about 15 μm. 25. The method of claim 21 including providing the fluorinated carbon synthesized from the fibrous carbonaceous material having a particle size surface area percent of less than about 3.5. 26. The method of claim 21 including providing the fluorinated carbon synthesized from the fibrous carbonaceous material having a mean DTA exotherm of about 652° C. to about 656° C. 27. The method of claim 21 including selecting the second cathode active material from the group consisting of silver vanadium oxide, copper silver vanadium oxide, V 2 O 5 , MnO 2 , LiCoO 2 , LiNiO 2 , LiMnO 2 , CuO, TiS, CuS, FeS, FeS 2 , copper vanadium oxide, and mixtures thereof. 28. The method of claim 21 wherein the anode is lithium, the first cathode active material is CF x and the second cathode active material is SVO. 29. The method of claim 21 including providing the cathode having the configuration: SVO/current collector/CF x /current collector/SVO. 30. The method of claim 21 including providing the cathode having the configuration: SVO/current collector/SVO/CF x /SVO/current collector/SVO. 31. The method of claim 22 including providing the anode of lithium and the cathode having the configuration: SVO/current collector/CF x , with the SVO facing the lithium anode.
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