CA2229816C - Blended polymer gel electrolytes - Google Patents
Blended polymer gel electrolytes Download PDFInfo
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- CA2229816C CA2229816C CA002229816A CA2229816A CA2229816C CA 2229816 C CA2229816 C CA 2229816C CA 002229816 A CA002229816 A CA 002229816A CA 2229816 A CA2229816 A CA 2229816A CA 2229816 C CA2229816 C CA 2229816C
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M6/00—Primary cells; Manufacture thereof
- H01M6/14—Cells with non-aqueous electrolyte
- H01M6/18—Cells with non-aqueous electrolyte with solid electrolyte
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
- H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
- H01M10/0565—Polymeric materials, e.g. gel-type or solid-type
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/411—Organic material
- H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
- H01M50/417—Polyolefins
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/411—Organic material
- H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
- H01M50/426—Fluorocarbon polymers
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
- H01M50/497—Ionic conductivity
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M6/00—Primary cells; Manufacture thereof
- H01M6/14—Cells with non-aqueous electrolyte
- H01M6/18—Cells with non-aqueous electrolyte with solid electrolyte
- H01M6/181—Cells with non-aqueous electrolyte with solid electrolyte with polymeric electrolytes
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M2300/00—Electrolytes
- H01M2300/0085—Immobilising or gelification of electrolyte
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/60—Other road transportation technologies with climate change mitigation effect
- Y02T10/70—Energy storage systems for electromobility, e.g. batteries
Abstract
An electrolyte system (40) for use in connection with an electrochemical cell (10). The cell (10) includes a positive electrode (20) and a negative electrode (30) with the electrolyte system (40) disposed therebetween. The electrolyte system is a blended polymer gel electrolyte system including a liquid electrolyte species which may be either aqueous or non-aqueous and a blended polymer gel electrolyte support structure. The blended polymer gel electrolyte support structure includes at least a first phase adapted to absorb or otherwise engage the electrolyte active species and a second phase which is substantially inert and does not absorb the electrolyte active species. The second phase may be divided to reduce swelling of the gel electrolyte in the presence of the electrolyte active species, and further to enhance mechanical integrity of the support structure.
Description
W O 97/08765 PCT~US96/13467 BIE2~DED POLYl~' GEL EIE:CTROLYI~S
Te~hr ir~l Field ~; This invention relates in general to the field of electrolytes for electrochemical cells, and more particularly to polymer electrolytes for such cells.
R~ ~ ~u~d of the Inve;lltion There has been a great deal of interest in developing better and ~nore efficient methods for storing energy for applications such as radio comT~unication, satellites, portable computers, and electric vehicles to name but a few. Accordingly, there have been recent concerted efforts to develop high energy, cost effective batteries having improved performance 1~ characteristics.
Rechargeable, or secondary cells are more desirable than primary (non-rechargeable) cells since the associated chemical reactions which take place at the positive and negative electrodes of the battery are reversible. Electrodes for secondary cells are capable of being regenerated ao (i.e. recharged~ many times by the application of an electrical charge thereto. Numerous advanced electrode systems have been developed for storing electrical charge. Concurrently, much effort has been dedicated to the development of electrolytes capable of enhancing the capabilities of electrochemical cells.
Heretofore, electrolytes have been either liquid electrolytes as are found in conventional wet cell batteries, or solid films as are available in newer, more advanced battery systems. Each of these systems have inherent limitations, and related deficiencies which make them unsuitable for various applications.
Liquid electrolytes, while demonstrating acceptable ionic conductivity, tend to leak out of the cells into which they are sealed. While better manufacturing techniques have lessened the occurrence of leakage, cells still do leak potentially dangerous liquid electrolytes from time to time. This is particularly true of current lithium ion cells. Moreover, any leakage in the cell lessens the amount of electrolyte available in the cell, thus reducing the effectiveness of the cell. Cells using liquid electrolytes are also not available for all sizes and shapes of batteries.
W O 97/08765 PCTrUS96/13467 Conversely, solid electrolytes are free from problems of leakage.
Howevel-, they have vastly inferior properties as compared to liquid electrolytes. For example, co~ventional solid electrolytes have ionic conductivities in the range of 10-5 S/cm (Siemens per c~ntimeter).
Whereas acceptable ionic conductivity is > 10-3 S/cm. Good ionic conductivity is necessary to ensure a battery system capable of delivering usable amounts of power for a given application. Good conductivity is necessary for the high rate operation demanded by, for ~mple, cellular telephones and satellites. Accordingly, solid electrolytes are not adequate 1~) for many high pelroLmance battery systems.
While solid electrolytes are intended to replace the comhin~ion of liquid electrolytes and separators used in conventional batteries, the limitations described hereinabove have prevented them from being fully implamented. One class of solid electrolytes, specifically gel electrolytes, 16 have shown some promise. Gel electrolytes contain a significant fraction of solvents (or plasticizers) in addition to the salt and polymer of the electrolyte itself. One processing route that can be used to assemble a battery with a gel electrolyte is to leave out the solvent until after the cell is fabricated. The cell may then be immersed in the solvent and a gel is ao formed as the solvent is absorbed. Two problems, however, may arise during solvent absorption: (1) the gel electrolyte may lack sufficient mechanical integrity to prevent shorting between the electrodes; and/or (2) ~ces.sive swelling accompanies the gel formation. Each of these problems is a significant limitation to the successful implemenk~tion of gel
Te~hr ir~l Field ~; This invention relates in general to the field of electrolytes for electrochemical cells, and more particularly to polymer electrolytes for such cells.
R~ ~ ~u~d of the Inve;lltion There has been a great deal of interest in developing better and ~nore efficient methods for storing energy for applications such as radio comT~unication, satellites, portable computers, and electric vehicles to name but a few. Accordingly, there have been recent concerted efforts to develop high energy, cost effective batteries having improved performance 1~ characteristics.
Rechargeable, or secondary cells are more desirable than primary (non-rechargeable) cells since the associated chemical reactions which take place at the positive and negative electrodes of the battery are reversible. Electrodes for secondary cells are capable of being regenerated ao (i.e. recharged~ many times by the application of an electrical charge thereto. Numerous advanced electrode systems have been developed for storing electrical charge. Concurrently, much effort has been dedicated to the development of electrolytes capable of enhancing the capabilities of electrochemical cells.
Heretofore, electrolytes have been either liquid electrolytes as are found in conventional wet cell batteries, or solid films as are available in newer, more advanced battery systems. Each of these systems have inherent limitations, and related deficiencies which make them unsuitable for various applications.
Liquid electrolytes, while demonstrating acceptable ionic conductivity, tend to leak out of the cells into which they are sealed. While better manufacturing techniques have lessened the occurrence of leakage, cells still do leak potentially dangerous liquid electrolytes from time to time. This is particularly true of current lithium ion cells. Moreover, any leakage in the cell lessens the amount of electrolyte available in the cell, thus reducing the effectiveness of the cell. Cells using liquid electrolytes are also not available for all sizes and shapes of batteries.
W O 97/08765 PCTrUS96/13467 Conversely, solid electrolytes are free from problems of leakage.
Howevel-, they have vastly inferior properties as compared to liquid electrolytes. For example, co~ventional solid electrolytes have ionic conductivities in the range of 10-5 S/cm (Siemens per c~ntimeter).
Whereas acceptable ionic conductivity is > 10-3 S/cm. Good ionic conductivity is necessary to ensure a battery system capable of delivering usable amounts of power for a given application. Good conductivity is necessary for the high rate operation demanded by, for ~mple, cellular telephones and satellites. Accordingly, solid electrolytes are not adequate 1~) for many high pelroLmance battery systems.
While solid electrolytes are intended to replace the comhin~ion of liquid electrolytes and separators used in conventional batteries, the limitations described hereinabove have prevented them from being fully implamented. One class of solid electrolytes, specifically gel electrolytes, 16 have shown some promise. Gel electrolytes contain a significant fraction of solvents (or plasticizers) in addition to the salt and polymer of the electrolyte itself. One processing route that can be used to assemble a battery with a gel electrolyte is to leave out the solvent until after the cell is fabricated. The cell may then be immersed in the solvent and a gel is ao formed as the solvent is absorbed. Two problems, however, may arise during solvent absorption: (1) the gel electrolyte may lack sufficient mechanical integrity to prevent shorting between the electrodes; and/or (2) ~ces.sive swelling accompanies the gel formation. Each of these problems is a significant limitation to the successful implemenk~tion of gel
2~ electrolytes in electrochemical cells.
Accordingly, there exists a need for a new electrolyte system which comhines the properties of good mechanical integrity, as well as the ability to absorb sufficient amounts of liquid electrolytes so as to produce an electrolyte with the high ionic conductivity of liquid electrolytes. The 30 electrolytes so formed should also avoid excessive swelling, and all the problems associated therewith BriefDesc~ip~on of 1;he D~w~
FIG. 1 is a s-hem~tic representation of an electrochemical cell in 35 accordance with the instant invention;
FIG. 2 is a chart illustrating the weight increase in percent for various polymer and polymer blend materials as a ~unction of time;
W O 97/08765 PCTrUS96/13467 FIG. 3 is a photograph, taken with optical microscopy illustrating the structure of the polymer blend electrolyte system support structure in accordance with the instant inventiom; and FIG. 4 is a chart illustrating a series of charge/discharge curves for 5 an electrochemical cell iIlcorporating a polymer blend support structure in accordance with the instant invention.
Detailed Descrip~on of 1~he I~ ~nt While the specification concludes with claims defining the features 10 of the invention that are regarded as llovel, it is believed that the invention will be better understood from a consideration of the following description in conjunction with the dlawillg figures, in which like reference numerals are carried forward.
Referring now to FIG. 1, there is illustrated therein a srhem~tic lEj repres~nt~t.ior of an electrochemical cell in accordance with the instant invention. The cell 10 includes a positive electrode 20 and a negative electrode 30. The positive electrode 20 may be fabricated of any of a number of chemical systems known to those of ordinary skill in the art. Exa~nples of such systems include mAn~Anese oxide, nickel oxide, cobalt oxide, ao vanadium oxide, and comhin~t,ions thereof. The negative electrode 30 may likewise be fab~icated from any of a number of electrode materials known to those of ordinary skill in the art. S,election of the negative electrode material is dependent on the selection of the positive electrode so as to assure an electrochemical cell which will function properly for a given 2~ application. In this context, the negative electrode may be fabricated from alkali metals, alkali metal alloys, carbon, graphite, petroleum coke, and comhinAtions thereof. The types of negative and positive electrode materials recited above are typically associated with lithium battery cells.
It is to be noted however that the invention is not so limited; the blended 30 polymer electrolyte system of the instant invention may be advantageously employed with nickel-cadmium, nick,el-metal hydride, lead-acid, or any other battery system.
Operatively disposed between the positive 20 and negative 30 electrodes is an electrolyte system 40. The electrolyte system 40 comprises
Accordingly, there exists a need for a new electrolyte system which comhines the properties of good mechanical integrity, as well as the ability to absorb sufficient amounts of liquid electrolytes so as to produce an electrolyte with the high ionic conductivity of liquid electrolytes. The 30 electrolytes so formed should also avoid excessive swelling, and all the problems associated therewith BriefDesc~ip~on of 1;he D~w~
FIG. 1 is a s-hem~tic representation of an electrochemical cell in 35 accordance with the instant invention;
FIG. 2 is a chart illustrating the weight increase in percent for various polymer and polymer blend materials as a ~unction of time;
W O 97/08765 PCTrUS96/13467 FIG. 3 is a photograph, taken with optical microscopy illustrating the structure of the polymer blend electrolyte system support structure in accordance with the instant inventiom; and FIG. 4 is a chart illustrating a series of charge/discharge curves for 5 an electrochemical cell iIlcorporating a polymer blend support structure in accordance with the instant invention.
Detailed Descrip~on of 1~he I~ ~nt While the specification concludes with claims defining the features 10 of the invention that are regarded as llovel, it is believed that the invention will be better understood from a consideration of the following description in conjunction with the dlawillg figures, in which like reference numerals are carried forward.
Referring now to FIG. 1, there is illustrated therein a srhem~tic lEj repres~nt~t.ior of an electrochemical cell in accordance with the instant invention. The cell 10 includes a positive electrode 20 and a negative electrode 30. The positive electrode 20 may be fabricated of any of a number of chemical systems known to those of ordinary skill in the art. Exa~nples of such systems include mAn~Anese oxide, nickel oxide, cobalt oxide, ao vanadium oxide, and comhin~t,ions thereof. The negative electrode 30 may likewise be fab~icated from any of a number of electrode materials known to those of ordinary skill in the art. S,election of the negative electrode material is dependent on the selection of the positive electrode so as to assure an electrochemical cell which will function properly for a given 2~ application. In this context, the negative electrode may be fabricated from alkali metals, alkali metal alloys, carbon, graphite, petroleum coke, and comhinAtions thereof. The types of negative and positive electrode materials recited above are typically associated with lithium battery cells.
It is to be noted however that the invention is not so limited; the blended 30 polymer electrolyte system of the instant invention may be advantageously employed with nickel-cadmium, nick,el-metal hydride, lead-acid, or any other battery system.
Operatively disposed between the positive 20 and negative 30 electrodes is an electrolyte system 40. The electrolyte system 40 comprises
3~ a polymer blend including at least two polymers adapted to function as a support structure and an electrolyte active species. The electrolyte act*e species may be either a liquid or solid, and may further include a plasticizer or solvent. Preferably, the electrolyte active species is a liquid electrolyte adapted to promote ion transport between the positive and negative electrodes, which liquid is absorbed into the blended polymer support structure.
As noted above, in the fabrication of polymer gel electrolytes, two problems arise during solvent absorption. The first problem relates to the lack of sufficient mechanical integrity to prevent electrical shorting between the electrodes and the second problem relates to excess*e swelling which often accompanies the gel formation as the polymer is 10 being immersed in the liquid electrolyte species. The instant polymer blend electrolyte system solves these problems by providing a polymer blend, such as a two phase polymer blend~ in which at least one polymer is provided for purposes of absorbing the electrolyte active species, while at least a second polymer, which either does not absorb electrolytes or at best 16 absorbs very little electrolyte, provides mechanical integrity. As the mechanical integrity is improved, shorting between the electrodes is reduced or elimin~ted.
In addition to improving the mechanical integ~ty of the electrolyte, the second polymeric phase reduces the rate of electrolyte absorption. By 20 slowing the rate of absorption, excess*e swelling can be avoided and hence the problems encountered in the prior art devices. It is to be understood that while the system is described above refers to two phases, the invention is not so limited. Indeed, the polymer blend electrolyte system may be a multiphase system in which one or more phases 2~ contribute to electrolyte active species absorption, and one or more phases contributes to improved mechanical integrity. The operative distinction however is the presence of discrete phases in a polymer blend, as opposed to the co-polymers common in other polymeric electrolyte systems.
The liquid electrolyte absorbed by the support structure is selected to 30 optimize performance of the positive 20 and negative 30 electrode couple.
Thus, for lithium type cells the liquid electrolyte absorbed by the support structure is typically a solution of an alkali metal salt, or combination of salts, dissolved in a non-protonic organic solvent or solvents. Typical alkali metal salts include, but are not limited to, salts having the fo~mula 3~ M+X- where M+ is an alkali metal cation such as Li+, Na+, K+ and comhin~tions thereof; and X~ is an anion such as Cl-, Br~, I-, C104-, BF4-, P1~6-, ASF6-~ SbF6-, CH3C02-, CF3S03-, (cF3o2)2N- (CF3S02)2N-, W O 97/08765 PCT~US96/13467 (CF3SO2)3C-, and comhin~t.ions thereof. Non-protonic organic solvents include, but are not limited to, propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahyd~oîuran, and combinations thereof. For other electrode combinations, other electrolyte active species are preferred, such as KOH, may be emLployed.
Referring now to FIG. 2, there is illustrated therein a chart describing the weight increase in percent of various polymer gel 10 electrolyte materials versus time. This chart specifically illustrates the differences found for common homopolymers and copolymers versus polymer blends according to the instant invention. Accordingly, as is shown by line 52, a low crystallinity polyvinylidene fluoride (PVDF) homopolymer known as KYNAR~)461 (Kynar is a registered trademark of 15 Elf Atochem North America, Inc.) demonstrated e~ el.-ely high increases in weight with the absorpti~n of liquid electrolytes in a relatively short period of time. Electrolyte absorption is so high as to cause the resulting gel to expand into the electrodes. This expansion lowers conductivity between the electrodes thereby seriously degrading the 20 electrochemical performance of cells into which the electrolyte is incorporated. Line 54 illustrates the absorption properties of a PVDF/polytetrafluoroethylene copolymer (PTFE) known as KYNAR(~)7201.
It may be appreciated from a perusal of FIG. 2, line 54, that lower electrolyte absorption was demonstrated by the PVDF/PTFE copolymer.
2~ This lower absorption substantially reduced the problems associated with gel exp~n.cion as experienced by the PVDF homopolymer. However, cells constructed from this copolyL{ler experienced short circuiting between the electrodes due to poor mechanical strength of the gel electrolyte.
A polymer blend, as opposed to a copoly3mer, was prepared using a 30 comhin~ti-~n of KYNAR~) 461 and 18~o high density polyethylene (~IDPE).
The polymer blend so synthesized displayed good mechanical strength and did not absorb excessive electrolyte as maybe appreciated from line ~6 of FIG. 2. Electrochemical cells constructed using this polymer blend did not experience shorting during the assembly, and yielded excellent 35 electrochemical performance. It is to be noted that the three examples described in FIG. 2 employed a liquid electrolyte consisting of lM LiPF6 including a solvent or plasticizer consisting of a 50% propylene carbonate, and 50% ethylene carbonate.
While FIG. 2 illustrates the use of a polyvinylidene fluoride-HDPE
polymer blend, it is contempl~ted that the concept of using a polymer blend could easily be extended to other gel electrolyte systems, both aqueous and non-aqueous, in order to improve mechanical strength and/or limit the rate of electrolyte absorption. In this regard, the first polymer in the polymer system or the absorbing or gel forming polymer, may be selected from the group of polymers including PVDF, polyurethane, polyethylene oxide, polyacrylonitrile, polymethylmethacrylate, polyacrylamide, polyvinyl acetate, polyvinylpyrroliclinone, polytetraethylene glycol diacrylate, copolymers of any of the foregoing, and comhinqtions thereof.
The second component in the polymer blend, i.e., the nonabsorbing or inert component, may be selected from the group consisting of polyethylene, polypropylene, polytetrafluoroethylene, polystyrene, polyethyleneterephthalate, ethylene propylene diene monomer, nylon, and combinations thereof. In this regard, it should be noted that at least one polymer phase in the gel polymer electrolyte acts as a separator in the liquid electrolyte cell. The phase which acts as the separator is typically 2~) also the phase which provides mechanical stability to the entire electrolytesystem. With respect to the relative amounts of each polymer in the blend, it is contemplated that the second or non-absorbing component may comprise between 10 and 40% of the polymer systems, and preferably between 15 and 25%.
Referring now to FIG. 3, there is illustrated a photograph of a polymer blend of PVDF and HDPE in accordance with the instant invention. The photograph is taken with optical microscopy in which the image is m~gTlified 50x. As maybe appreciated from FIG. 3, two separate phases of polymers are present in the polymer blend of the instant invention. In FIG. 3, the electrolyte absorbing phase (PVDF) is identified by groupings or areas 80, 82, 84, 86, 88, while the non-absorbing polymer (HDPE) phase is identified by ~rou~ gs or areas 90, 92, 94, 96, 98. It may thus be appreciated that the polymer system of the instant invention is a two-phase system as opposed to a copolymer such as that typically used in 36 the prior art.
The invention may be filrther appreciated by the comparative examples provided hereinbelow.
-EX:AMPLES
Swelling analysis was conducted on a number of homopolymers, copolymers, and polymer blends in accordance with the instant invention.
Each of the polymers was swelled in 100~C lM PF6 in a 50~o-50~o solution of propylene carbonate/ethylene carbonate (PC/EC) solvent. The results are illustrated in the table below:
Product l~me Wei~t Thi-l~s~ Co .. ~ nt KYNAR 461 0 9.1 mg 59,um 30 sec 11.7mg 63~Lm 2 min 40.1 mg collapsed 5 min KYNAR 761 0 11.3mg 67,um 30 sec 17.0 mg 86~m 2 min 24.2 mg 82,um folding 5 min 23.4mg folded KYNAR 7201 0 11.5 mg 66~m 30 sec 19.4 mg pressed into mesh 2 min 22.9 mg pressed into mesh 5 min gooey-dissolving not embedded in mesh 82:18 0 11.6mg 59,um KYNAR 461: 30 sec 12.3 mg 62~mSlight puckering HDPE 2 min 18.0 mg 65,umSlight puckering 5 min 25.7 mg 91~mSlight puckering 75:25 0 9.5 mg 61~
KYNAR 461 30 sec 12.4 mg 80,unnirregular surface LDPE 2 min 16.1 mg 87~m 5 min 16.3 mg 87,um W O 97/08765 PCT~US96/13467 ~g~lMoPIJE I
Polymer blends were produced using a bench top extruder heated to temperatures between 150 and 200~ C. Polymer blend films were produced by hot pressing polymer blends between polished metal plates, at temperatures between 150 and 200~ C. Homopolymer films of Kynar 461 and Kynar 761 as described above demonstrated significant uptake of liquid electrolyte act*e species (lM LiPF6 in a 50%-50% solution of PC/EC), but generally poor mechanical properties and tended to tear easily. Kynar 461 in particular collapsed as the electrolyte active species content lD exceeded 75%. The PVDF/PTFE copolymer, Kynar 7201, likewise showed poor mechanical properties.
By bl~ntlin~ the homopolymer (Kynar 461) with either LDPE or HDPE the electrolyte absorption was reduced; however, mechanical properties were substantially improved. For example, after five minutes 15 the 75:25 Kynar 461/LDPE blend absorbed 42% of the electrolyte active species (again lM LiPF6 in a 60%-50% solution of PC/EC), while the 82:18 Kynar 461:HDPE blend absorbed 55% of the electrolyte active species.
Impedance measurements were carried out for each sample, to determine the ionic conductivies of the films. For the 75:25 Kynar 461/LDPE blend, 20 conductivity measured lx10-4 Siemens per c~ntim~ter (S/cm), while conductivity for the 82: 18 Kynar 461:HDPE blend was 6x10-4 S/cm. The conductivity of the 82: 18 Kynar 461:HDPE blend is particularly suitable for application in lithium electrochemical cells, as is shown in ~,~Ample II
below.
2~ MpLE II
To demonstrate the suitability of a blended polymer electrolyte for application in lithium ion cells, a cell was constructed using a petroleum coke anode and a LiCoO2 cathode. The polymer blend electrolyte system comprised the 82:18 Kynar 461:HDPE blend, soaked in lM LiPF6 in a 60%-3Q 50% solution of PC/EC. The electrodes were prepared by mi~rin~ and hotpressing powders with the following compositions:
anode: 81% petroleum coke, 19% Kynar 461 cathode: 73% LiCoO2, 16% graphite, 12% Kynar 461.
A cell was formed by lAmin~ting the electrodes to the blended 35 polymer. A copper mesh current collector was used for the anode and an aluminum mesh current collector for the cathode. The liquid electrolyte CA 022298l6 l998-02-l8 W O 97/08765 PCTrUS96/13467 active species was introduced by soaking in the solution at 100~C. The resulting electrode ~limen.~ions were 1.8cm x 2.0cm x 130,um.
A cell so fabricated was cycled at 1.0 milli~qmpfi (mA~ between 4.2 and 2.7 volts, with one hour rests between each charge/discharge cycle.
ReferIing now to FIG. 4, there is illustrated therein the charge/discharge J profiles for the first ten cycles of the cell fabricated according to this example. As may be appreciated from a perusal of FIG. 4, the cell demonstrated good cell ~evef~ibility and overall good cell performance using the blended polymer electrode.
1() While the l)~efelfed embodiments of the invention have been illustrated and described, it will be clear that the invention is not so limited. Nllmerous modifications, changes, variations, substitutions and equivalents will occur to those skilled in the art without departing from the spirit and scope of the present invention as defined by the appended ~5 claims.
What is claimed is:
As noted above, in the fabrication of polymer gel electrolytes, two problems arise during solvent absorption. The first problem relates to the lack of sufficient mechanical integrity to prevent electrical shorting between the electrodes and the second problem relates to excess*e swelling which often accompanies the gel formation as the polymer is 10 being immersed in the liquid electrolyte species. The instant polymer blend electrolyte system solves these problems by providing a polymer blend, such as a two phase polymer blend~ in which at least one polymer is provided for purposes of absorbing the electrolyte active species, while at least a second polymer, which either does not absorb electrolytes or at best 16 absorbs very little electrolyte, provides mechanical integrity. As the mechanical integrity is improved, shorting between the electrodes is reduced or elimin~ted.
In addition to improving the mechanical integ~ty of the electrolyte, the second polymeric phase reduces the rate of electrolyte absorption. By 20 slowing the rate of absorption, excess*e swelling can be avoided and hence the problems encountered in the prior art devices. It is to be understood that while the system is described above refers to two phases, the invention is not so limited. Indeed, the polymer blend electrolyte system may be a multiphase system in which one or more phases 2~ contribute to electrolyte active species absorption, and one or more phases contributes to improved mechanical integrity. The operative distinction however is the presence of discrete phases in a polymer blend, as opposed to the co-polymers common in other polymeric electrolyte systems.
The liquid electrolyte absorbed by the support structure is selected to 30 optimize performance of the positive 20 and negative 30 electrode couple.
Thus, for lithium type cells the liquid electrolyte absorbed by the support structure is typically a solution of an alkali metal salt, or combination of salts, dissolved in a non-protonic organic solvent or solvents. Typical alkali metal salts include, but are not limited to, salts having the fo~mula 3~ M+X- where M+ is an alkali metal cation such as Li+, Na+, K+ and comhin~tions thereof; and X~ is an anion such as Cl-, Br~, I-, C104-, BF4-, P1~6-, ASF6-~ SbF6-, CH3C02-, CF3S03-, (cF3o2)2N- (CF3S02)2N-, W O 97/08765 PCT~US96/13467 (CF3SO2)3C-, and comhin~t.ions thereof. Non-protonic organic solvents include, but are not limited to, propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahyd~oîuran, and combinations thereof. For other electrode combinations, other electrolyte active species are preferred, such as KOH, may be emLployed.
Referring now to FIG. 2, there is illustrated therein a chart describing the weight increase in percent of various polymer gel 10 electrolyte materials versus time. This chart specifically illustrates the differences found for common homopolymers and copolymers versus polymer blends according to the instant invention. Accordingly, as is shown by line 52, a low crystallinity polyvinylidene fluoride (PVDF) homopolymer known as KYNAR~)461 (Kynar is a registered trademark of 15 Elf Atochem North America, Inc.) demonstrated e~ el.-ely high increases in weight with the absorpti~n of liquid electrolytes in a relatively short period of time. Electrolyte absorption is so high as to cause the resulting gel to expand into the electrodes. This expansion lowers conductivity between the electrodes thereby seriously degrading the 20 electrochemical performance of cells into which the electrolyte is incorporated. Line 54 illustrates the absorption properties of a PVDF/polytetrafluoroethylene copolymer (PTFE) known as KYNAR(~)7201.
It may be appreciated from a perusal of FIG. 2, line 54, that lower electrolyte absorption was demonstrated by the PVDF/PTFE copolymer.
2~ This lower absorption substantially reduced the problems associated with gel exp~n.cion as experienced by the PVDF homopolymer. However, cells constructed from this copolyL{ler experienced short circuiting between the electrodes due to poor mechanical strength of the gel electrolyte.
A polymer blend, as opposed to a copoly3mer, was prepared using a 30 comhin~ti-~n of KYNAR~) 461 and 18~o high density polyethylene (~IDPE).
The polymer blend so synthesized displayed good mechanical strength and did not absorb excessive electrolyte as maybe appreciated from line ~6 of FIG. 2. Electrochemical cells constructed using this polymer blend did not experience shorting during the assembly, and yielded excellent 35 electrochemical performance. It is to be noted that the three examples described in FIG. 2 employed a liquid electrolyte consisting of lM LiPF6 including a solvent or plasticizer consisting of a 50% propylene carbonate, and 50% ethylene carbonate.
While FIG. 2 illustrates the use of a polyvinylidene fluoride-HDPE
polymer blend, it is contempl~ted that the concept of using a polymer blend could easily be extended to other gel electrolyte systems, both aqueous and non-aqueous, in order to improve mechanical strength and/or limit the rate of electrolyte absorption. In this regard, the first polymer in the polymer system or the absorbing or gel forming polymer, may be selected from the group of polymers including PVDF, polyurethane, polyethylene oxide, polyacrylonitrile, polymethylmethacrylate, polyacrylamide, polyvinyl acetate, polyvinylpyrroliclinone, polytetraethylene glycol diacrylate, copolymers of any of the foregoing, and comhinqtions thereof.
The second component in the polymer blend, i.e., the nonabsorbing or inert component, may be selected from the group consisting of polyethylene, polypropylene, polytetrafluoroethylene, polystyrene, polyethyleneterephthalate, ethylene propylene diene monomer, nylon, and combinations thereof. In this regard, it should be noted that at least one polymer phase in the gel polymer electrolyte acts as a separator in the liquid electrolyte cell. The phase which acts as the separator is typically 2~) also the phase which provides mechanical stability to the entire electrolytesystem. With respect to the relative amounts of each polymer in the blend, it is contemplated that the second or non-absorbing component may comprise between 10 and 40% of the polymer systems, and preferably between 15 and 25%.
Referring now to FIG. 3, there is illustrated a photograph of a polymer blend of PVDF and HDPE in accordance with the instant invention. The photograph is taken with optical microscopy in which the image is m~gTlified 50x. As maybe appreciated from FIG. 3, two separate phases of polymers are present in the polymer blend of the instant invention. In FIG. 3, the electrolyte absorbing phase (PVDF) is identified by groupings or areas 80, 82, 84, 86, 88, while the non-absorbing polymer (HDPE) phase is identified by ~rou~ gs or areas 90, 92, 94, 96, 98. It may thus be appreciated that the polymer system of the instant invention is a two-phase system as opposed to a copolymer such as that typically used in 36 the prior art.
The invention may be filrther appreciated by the comparative examples provided hereinbelow.
-EX:AMPLES
Swelling analysis was conducted on a number of homopolymers, copolymers, and polymer blends in accordance with the instant invention.
Each of the polymers was swelled in 100~C lM PF6 in a 50~o-50~o solution of propylene carbonate/ethylene carbonate (PC/EC) solvent. The results are illustrated in the table below:
Product l~me Wei~t Thi-l~s~ Co .. ~ nt KYNAR 461 0 9.1 mg 59,um 30 sec 11.7mg 63~Lm 2 min 40.1 mg collapsed 5 min KYNAR 761 0 11.3mg 67,um 30 sec 17.0 mg 86~m 2 min 24.2 mg 82,um folding 5 min 23.4mg folded KYNAR 7201 0 11.5 mg 66~m 30 sec 19.4 mg pressed into mesh 2 min 22.9 mg pressed into mesh 5 min gooey-dissolving not embedded in mesh 82:18 0 11.6mg 59,um KYNAR 461: 30 sec 12.3 mg 62~mSlight puckering HDPE 2 min 18.0 mg 65,umSlight puckering 5 min 25.7 mg 91~mSlight puckering 75:25 0 9.5 mg 61~
KYNAR 461 30 sec 12.4 mg 80,unnirregular surface LDPE 2 min 16.1 mg 87~m 5 min 16.3 mg 87,um W O 97/08765 PCT~US96/13467 ~g~lMoPIJE I
Polymer blends were produced using a bench top extruder heated to temperatures between 150 and 200~ C. Polymer blend films were produced by hot pressing polymer blends between polished metal plates, at temperatures between 150 and 200~ C. Homopolymer films of Kynar 461 and Kynar 761 as described above demonstrated significant uptake of liquid electrolyte act*e species (lM LiPF6 in a 50%-50% solution of PC/EC), but generally poor mechanical properties and tended to tear easily. Kynar 461 in particular collapsed as the electrolyte active species content lD exceeded 75%. The PVDF/PTFE copolymer, Kynar 7201, likewise showed poor mechanical properties.
By bl~ntlin~ the homopolymer (Kynar 461) with either LDPE or HDPE the electrolyte absorption was reduced; however, mechanical properties were substantially improved. For example, after five minutes 15 the 75:25 Kynar 461/LDPE blend absorbed 42% of the electrolyte active species (again lM LiPF6 in a 60%-50% solution of PC/EC), while the 82:18 Kynar 461:HDPE blend absorbed 55% of the electrolyte active species.
Impedance measurements were carried out for each sample, to determine the ionic conductivies of the films. For the 75:25 Kynar 461/LDPE blend, 20 conductivity measured lx10-4 Siemens per c~ntim~ter (S/cm), while conductivity for the 82: 18 Kynar 461:HDPE blend was 6x10-4 S/cm. The conductivity of the 82: 18 Kynar 461:HDPE blend is particularly suitable for application in lithium electrochemical cells, as is shown in ~,~Ample II
below.
2~ MpLE II
To demonstrate the suitability of a blended polymer electrolyte for application in lithium ion cells, a cell was constructed using a petroleum coke anode and a LiCoO2 cathode. The polymer blend electrolyte system comprised the 82:18 Kynar 461:HDPE blend, soaked in lM LiPF6 in a 60%-3Q 50% solution of PC/EC. The electrodes were prepared by mi~rin~ and hotpressing powders with the following compositions:
anode: 81% petroleum coke, 19% Kynar 461 cathode: 73% LiCoO2, 16% graphite, 12% Kynar 461.
A cell was formed by lAmin~ting the electrodes to the blended 35 polymer. A copper mesh current collector was used for the anode and an aluminum mesh current collector for the cathode. The liquid electrolyte CA 022298l6 l998-02-l8 W O 97/08765 PCTrUS96/13467 active species was introduced by soaking in the solution at 100~C. The resulting electrode ~limen.~ions were 1.8cm x 2.0cm x 130,um.
A cell so fabricated was cycled at 1.0 milli~qmpfi (mA~ between 4.2 and 2.7 volts, with one hour rests between each charge/discharge cycle.
ReferIing now to FIG. 4, there is illustrated therein the charge/discharge J profiles for the first ten cycles of the cell fabricated according to this example. As may be appreciated from a perusal of FIG. 4, the cell demonstrated good cell ~evef~ibility and overall good cell performance using the blended polymer electrode.
1() While the l)~efelfed embodiments of the invention have been illustrated and described, it will be clear that the invention is not so limited. Nllmerous modifications, changes, variations, substitutions and equivalents will occur to those skilled in the art without departing from the spirit and scope of the present invention as defined by the appended ~5 claims.
What is claimed is:
Claims (19)
1. A polymer gel electrolyte system for use in an electrochemical cell having positive and negative electrodes, said polymer gel electrolyte system comprising:
a liquid electrolyte active species adapted to promote ion transport between said positive and said negative electrodes consisting of an alkali metal salt in a solvent selected from the group consisting of propylene carbonate, ethylene carbonate, diethyl carbonate, dimethylcarbonate, dipropylcarbonate, dimethylsulfoxide, acetonitrile, dimethoxyethane, tetrahydrofuran, and combinations thereof; and a two-phase polymer blend gel electrolyte support structure including at least a first phase including at least one polymer for absorbing said electrolyte active species and a second phase including at least one polymer for enhancing mechanical integrity of the polymer blend.
a liquid electrolyte active species adapted to promote ion transport between said positive and said negative electrodes consisting of an alkali metal salt in a solvent selected from the group consisting of propylene carbonate, ethylene carbonate, diethyl carbonate, dimethylcarbonate, dipropylcarbonate, dimethylsulfoxide, acetonitrile, dimethoxyethane, tetrahydrofuran, and combinations thereof; and a two-phase polymer blend gel electrolyte support structure including at least a first phase including at least one polymer for absorbing said electrolyte active species and a second phase including at least one polymer for enhancing mechanical integrity of the polymer blend.
2. A gel electrolyte system as in claim 1, wherein said first phase polymer is selected from the group consisting of polyvinylidene fluoride (PVDF), polyurethane, polyethylene oxide, polyacrylonitrile, polymethylmethacrylate, polyacrylamide, polyvinyl acetate, polyvinylpyrrolidinone, polytetraethylene glycol diacrylate, copolymers of any of the foregoing, and combinations thereof.
3. A gel electrolyte system as in claim 1, wherein said second phase polymer is selected from the group consisting of polyethylene, polypropylene, polytetrafluoroethylene, polystyrene, polyethyleneterephthalate, ethylene propylene diene monomer, nylon, and combinations thereof.
4. A gel electrolyte system as in claim 1, wherein said alkali metal salt having the formula M+ X-, where:
M+ is an alkaline metal canon selected from the group consisting of Li+ and Na+, K+ ; and X- is a anion selected from the group consisting of Cl-, Br , I-, C104-, BF4-, PF6-, AsF6-, SbF6-, CH3 CO2-, CF; SO3-, (CF3SO2)2 N2-, (CF3SO2)3 C-, and combinations thereof.
M+ is an alkaline metal canon selected from the group consisting of Li+ and Na+, K+ ; and X- is a anion selected from the group consisting of Cl-, Br , I-, C104-, BF4-, PF6-, AsF6-, SbF6-, CH3 CO2-, CF; SO3-, (CF3SO2)2 N2-, (CF3SO2)3 C-, and combinations thereof.
5. A gel electrolyte system as in claim 1, wherein said electrolyte active species is LiPF6, in a propylene carbonate/ethylene carbonate solvent and wherein said polymer blend includes a first phase consisting of polyvinylidene fluoride and a second phase consisting of polyethylene.
6. A gel electrolyte system as in claim 1, wherein the second phase polymer comprises between 10 and 40% of the two phase polymer support structure.
7. A gel electrolyte system as in claim 1, wherein the second phase polymer comprises between 15 and 25% of the two phase polymer support structure.
8. A polymer gel electrolyte system for use in an electrochemical cell having positive and negative electrodes, said polymer gel electrolyte system comprising:
a liquid electrolyte active species for promoting ion transport between said positive and said negative electrodes; and a two-phase polymer blend gel electrolyte support structure including at least a first polymer phase for absorbing said electrolyte active species, said first polymer phase being fabricated of one or more polymers selected from the group consisting of polyvinylidene fluoride (PVDF), polyurethane, polyethylene oxide, polyacrylonitrile, polymethylmethacrylate, polyacrylamide, polyvinyl acetate, polyvinylpyrrolidinone, polytetraethylene glycol diacrylate, copolymers of any of the foregoing, and combinations thereof and a second polymer phase for enhancing mechanical integrity of the polymer blend said second polymer phase fabricated of one or more polymers selected from the group consisting of polyethylene, polypropylene, polytetrafluoroethylene, polystyrene, polyethyleneterephthalate, ethylene propylene diene monomer, nylon, and combinations thereof.
a liquid electrolyte active species for promoting ion transport between said positive and said negative electrodes; and a two-phase polymer blend gel electrolyte support structure including at least a first polymer phase for absorbing said electrolyte active species, said first polymer phase being fabricated of one or more polymers selected from the group consisting of polyvinylidene fluoride (PVDF), polyurethane, polyethylene oxide, polyacrylonitrile, polymethylmethacrylate, polyacrylamide, polyvinyl acetate, polyvinylpyrrolidinone, polytetraethylene glycol diacrylate, copolymers of any of the foregoing, and combinations thereof and a second polymer phase for enhancing mechanical integrity of the polymer blend said second polymer phase fabricated of one or more polymers selected from the group consisting of polyethylene, polypropylene, polytetrafluoroethylene, polystyrene, polyethyleneterephthalate, ethylene propylene diene monomer, nylon, and combinations thereof.
9. A gel electrolyte system as in claim 8, wherein said liquid electrolyte active species further includes a solvent selected from the group consisting of propylene carbonate, ethylene carbonate, diethyl carbonate, dimethylcarbonate, dipropylcarbonate, dimethylsulfoxide, acetonitrile, dimethoxyethane, tetrahydrofuran, and combinations thereof.
10. A gel electrolyte system as in claim 8, wherein said liquid electrolyte active species includes an alkaline metal salt having the formula M+X-, where:
M+ is an alkaline metal cation selected from the group consisting of Li+ and Na+.
K+; and X- is a anion selected from the group consisting of Cl-, Br-, I-, ClO4-, BF4-, PF6-, AsF6-, SbF6-, CH3CO2-, CF3SO3-, (CF3SO2)2 N2-, (CF3SO2)3 C-, and combinations thereof.
M+ is an alkaline metal cation selected from the group consisting of Li+ and Na+.
K+; and X- is a anion selected from the group consisting of Cl-, Br-, I-, ClO4-, BF4-, PF6-, AsF6-, SbF6-, CH3CO2-, CF3SO3-, (CF3SO2)2 N2-, (CF3SO2)3 C-, and combinations thereof.
11. A gel electrolyte system as in claim 8, wherein said electrolyte active species is LiPF6, in a propylene carbonate/ethylene carbonate solvent and wherein said polymer blend includes a first phase consisting of polyvinylidene fluoride and a second phase consisting of polyethylene.
12. A gel electrolyte system as in claim 8, wherein the second phase polymer comprises between 10 and 40% of the two phase polymer support structure.
13. A gel electrolyte system as in claim 8, wherein the second phase polymer comprises between 15 and 25% of the two phase polymer support structure.
14. An electrochemical cell comprising;
a positive electrode;
a negative electrode; and an electrolyte system comprising a liquid electrolyte active species, a solvent and a two-phase polymer blend gel electrolyte support structure consisting of a first polymer absorbing phase and a second polymer inert phase, wherein said liquid electrolyte active species is absorbed in said first polymer absorbing phase.
a positive electrode;
a negative electrode; and an electrolyte system comprising a liquid electrolyte active species, a solvent and a two-phase polymer blend gel electrolyte support structure consisting of a first polymer absorbing phase and a second polymer inert phase, wherein said liquid electrolyte active species is absorbed in said first polymer absorbing phase.
15. An electrochemical cell as in claim 14, wherein said first phase polymer is selected from the group consisting of polyvinylidene fluoride (PVDF), polyurethane, polyethylene oxide, polyacrylonitrile, polymethylmethacrylate, polyacrylamide, polyvinyl acetate, polyvinylpyrrolidinone, polytetraethylene glycol diacrylate, copolymers of any of the foregoing, and combinations thereof.
16. An electrochemical cell as in claim 14, wherein said second phase polymer is selected from the group consisting of polyethylene, polypropylene, polytetrafluoroethylene, polystyrene, polyethyleneterephthalate, ethylene propylene diene monomer, nylon, and combinations thereof.
17. An electrochemical cell as in claim 14. wherein said solvent selected from the group consisting of propylene carbonate, ethylene carbonate, diethylcarbonate, dimethylcarbonate, dipropylcarbonate, dimethylsulfoxide, acetonitrile, dimethoxyethane, tetrahydrofuran, and combinations thereof.
18. An electrochemical cell as in claim 14, wherein said electrolyte active species includes an alkaline metal salt having the formula M+X-, where:
M+ is an alkali metal cation selected from the group consisting of Li+ and Na+, K+; and M+ is an alkaline metal cation selected from the group consisting of Li+
and Na+, K+; and X- is a anion selected from the group consisting of Cl-, Br-, I-, ClO4-, BF4-, PF6-, AsF6-, SbF6-, CH3CO2-, CF3SO3-, (CF3SO2)2 N2-, (CF3SO2)3 C-, and combinations thereof.
M+ is an alkali metal cation selected from the group consisting of Li+ and Na+, K+; and M+ is an alkaline metal cation selected from the group consisting of Li+
and Na+, K+; and X- is a anion selected from the group consisting of Cl-, Br-, I-, ClO4-, BF4-, PF6-, AsF6-, SbF6-, CH3CO2-, CF3SO3-, (CF3SO2)2 N2-, (CF3SO2)3 C-, and combinations thereof.
19. An electrochemical cell as in claim 14, wherein said electrolyte active species is LiPF6, in a propylene carbonate/ethylene carbonate solvent and wherein said polymer blend includes a first phase consisting of polyvinylidene fluoride and a second phase consisting of polyethylene.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08/518,732 | 1995-08-24 | ||
| US08/518,732 US5658685A (en) | 1995-08-24 | 1995-08-24 | Blended polymer gel electrolytes |
| PCT/US1996/013467 WO1997008765A1 (en) | 1995-08-24 | 1996-08-20 | Blended polymer gel electrolytes |
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| Publication Number | Publication Date |
|---|---|
| CA2229816A1 CA2229816A1 (en) | 1997-03-06 |
| CA2229816C true CA2229816C (en) | 2003-08-19 |
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| CA002229816A Expired - Lifetime CA2229816C (en) | 1995-08-24 | 1996-08-20 | Blended polymer gel electrolytes |
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| US (2) | US5658685A (en) |
| EP (1) | EP0846346A4 (en) |
| JP (1) | JP3565861B2 (en) |
| KR (1) | KR100281589B1 (en) |
| CN (1) | CN1216164A (en) |
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| CN103311570B (en) * | 2013-05-10 | 2015-11-25 | 江苏科技大学 | Blended gel polymer electrolyte film of a kind of porous pattern and preparation method thereof |
| CN107645014A (en) * | 2014-01-02 | 2018-01-30 | 苏州宝时得电动工具有限公司 | Battery |
| CN103855360B (en) * | 2014-02-27 | 2016-08-17 | 宁德新能源科技有限公司 | Lithium ion battery and cathode pole piece thereof and preparation method |
| CN103872379B (en) * | 2014-03-21 | 2017-04-26 | 东莞新能源科技有限公司 | gel electrolyte of lithium ion battery |
| FR3054078B1 (en) * | 2016-07-13 | 2018-09-07 | Institut Polytechnique De Grenoble | ION CONDUCTION MATERIAL FOR ELECTROCHEMICAL GENERATOR AND METHODS OF MAKING |
| CN109841782A (en) * | 2017-11-28 | 2019-06-04 | 张家港市国泰华荣化工新材料有限公司 | A kind of quasi-solid electrolyte film and its preparation method and application |
| US10840550B2 (en) | 2018-09-13 | 2020-11-17 | Toyota Motor Engineering & Manufacturing North America, Inc. | Gel electrolyte for use in a magnesium battery |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5016991A (en) * | 1989-03-27 | 1991-05-21 | Ford Motor Company | Flexible, solid electrolyte useful in electrochromic devices |
| JP2856795B2 (en) * | 1989-12-05 | 1999-02-10 | 三菱化学株式会社 | Electrodes for secondary batteries |
| FR2674685B1 (en) * | 1991-03-29 | 1996-12-13 | Alsthom Cge Alcatel | SECONDARY LITHIUM ELECTROCHEMICAL GENERATOR WITH LIQUID ORGANIC ELECTROLYTE. |
| GB9121117D0 (en) * | 1991-10-03 | 1991-11-13 | Nat Res Dev | Ionically conductive polymer gels |
| AU652494B2 (en) * | 1991-11-15 | 1994-08-25 | Minnesota Mining And Manufacturing Company | Solid state conductive polymer compositions, biomedical electrodes containing such compositions, and method of preparing same |
| US5437943A (en) * | 1992-09-04 | 1995-08-01 | Ricoh Company, Ltd. | Positive electrode and secondary battery using the same |
| US5296318A (en) * | 1993-03-05 | 1994-03-22 | Bell Communications Research, Inc. | Rechargeable lithium intercalation battery with hybrid polymeric electrolyte |
| US5407593A (en) * | 1993-11-15 | 1995-04-18 | National Science Council | Polymeric electrolyte |
| US5387482A (en) * | 1993-11-26 | 1995-02-07 | Motorola, Inc. | Multilayered electrolyte and electrochemical cells used same |
| US5429890A (en) * | 1994-02-09 | 1995-07-04 | Valence Technology, Inc. | Cathode-active material blends of Lix Mn2 O4 |
-
1995
- 1995-08-24 US US08/518,732 patent/US5658685A/en not_active Expired - Lifetime
-
1996
- 1996-04-29 US US08/638,706 patent/US5639573A/en not_active Expired - Lifetime
- 1996-08-20 CN CN96196506A patent/CN1216164A/en active Pending
- 1996-08-20 CA CA002229816A patent/CA2229816C/en not_active Expired - Lifetime
- 1996-08-20 KR KR1019980701317A patent/KR100281589B1/en not_active IP Right Cessation
- 1996-08-20 JP JP51038897A patent/JP3565861B2/en not_active Expired - Lifetime
- 1996-08-20 EP EP96933732A patent/EP0846346A4/en not_active Withdrawn
- 1996-08-20 WO PCT/US1996/013467 patent/WO1997008765A1/en active IP Right Grant
Also Published As
| Publication number | Publication date |
|---|---|
| EP0846346A1 (en) | 1998-06-10 |
| US5639573A (en) | 1997-06-17 |
| JP3565861B2 (en) | 2004-09-15 |
| WO1997008765A1 (en) | 1997-03-06 |
| US5658685A (en) | 1997-08-19 |
| JP2001503906A (en) | 2001-03-21 |
| KR19990044084A (en) | 1999-06-25 |
| EP0846346A4 (en) | 2001-08-22 |
| CN1216164A (en) | 1999-05-05 |
| KR100281589B1 (en) | 2001-02-15 |
| CA2229816A1 (en) | 1997-03-06 |
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