WO2013181333A1 - Cellule électrochimique comprenant un nanoréseau contenant des nanofibres d'un polyimide réticulé - Google Patents

Cellule électrochimique comprenant un nanoréseau contenant des nanofibres d'un polyimide réticulé Download PDF

Info

Publication number
WO2013181333A1
WO2013181333A1 PCT/US2013/043256 US2013043256W WO2013181333A1 WO 2013181333 A1 WO2013181333 A1 WO 2013181333A1 US 2013043256 W US2013043256 W US 2013043256W WO 2013181333 A1 WO2013181333 A1 WO 2013181333A1
Authority
WO
WIPO (PCT)
Prior art keywords
electrochemical cell
electrode
polyimide
nanoweb
cross
Prior art date
Application number
PCT/US2013/043256
Other languages
English (en)
Inventor
T. Joseph Dennes
Eric P. Holowka
Original Assignee
E. I. Du Pont De Nemours And Company
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by E. I. Du Pont De Nemours And Company filed Critical E. I. Du Pont De Nemours And Company
Publication of WO2013181333A1 publication Critical patent/WO2013181333A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/52—Separators
    • 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
    • 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
    • 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
    • H01M50/44—Fibrous material
    • 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
    • H01M50/491—Porosity
    • 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
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • 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
    • H01M50/403—Manufacturing processes of separators, membranes or diaphragms
    • 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
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • 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

Definitions

  • the present invention is directed to a polyimide nanoweb comprising nanofibers of a cross-linked polyimide; a method of making a polyimide
  • nanoweb a separator comprising a polyimide nanoweb; and a multilayer article and an electrochemical cell comprising a separator.
  • Aromatic polyimide nanowebs are one of many candidates that are being explored for use as polymeric separators for electrochemical cells, liquid and air filters, and thermal insulation materials. Polyimide nanowebs are an excellent choice for high flux and/or high filtration efficiency applications due to relatively small pores and high porosity.
  • polyimide nanowebs are made by solution spinning processing of polyamic acid using various techniques such as, electrospinning,
  • rheological properties of the polyamic acid solution require rheological properties of the polyamic acid solution to be in a specific range in order to form a nanoweb having fiber size distribution in the desired range.
  • the rheological properties of the polyamic acid solution are controlled by the polyamic acid molecular weight and the solution concentration. Furthermore, the molecular weight of the polyamic acid solution impacts the mechanical properties of the nanoweb produced therefrom. Hence, the polyamic acid solution must have a molecular weight above a certain critical value in order to produce a nanoweb with suitable mechanical properties.
  • high concentration solutions of high molecular weight polyamic acid are typically too viscous to be compatible with the solution spinning processes.
  • polyimide nanowebs with suitable mechanical properties from high concentration solutions; polyimide nanowebs comprising nanofibers of a cross-linked polyimide; separator comprising polyimide nanowebs; and multilayer articles and electrochemical cells comprising separator.
  • nanoweb comprising nanofibers of a cross-linked polyimide, wherein the cross-linked polyimide is derived from an aromatic dianhydride, an aromatic diamine, and a reactive end-capper.
  • the reactive end-capper is at least one of a functionalized anhydride or a functionalized amine, functionalized with a reactive functionality selected from the group consisting of acetylene, vinyl, epoxide, nitrile, and ester.
  • the reactive end-capper is an acetylene-functionalized phthalic anhydride.
  • the acetylene-functionalized phthalic anhydride is selected from the group consisting of 4-phenylethynylphthalic anhydride (PEPA), ethynyl phthalic anhydride (EPA), pyromellitic ethynyl phthalic anhydride (PETA), methyl ethynyl phthalic anhydride (MEPA), and mixtures thereof.
  • PEPA 4-phenylethynylphthalic anhydride
  • EPA ethynyl phthalic anhydride
  • PETA pyromellitic ethynyl phthalic anhydride
  • MEPA methyl ethynyl phthalic anhydride
  • a nanoweb comprising nanofibers of a cross-linked polyimide, wherein the cross-linked polyimide comprises a cydotrimerized aromatic polyimide and wherein the cross-linked polyimide is derived from an aromatic dianhydride, an aromatic diamine, and an acetylene-functionalized phthalic anhydride.
  • the cross-linked polyimide is derived from pyromellitic dianhydride (PMDA), oxydianiline (ODA), and an acetylene-functionalized phthalic anhydride.
  • the cydotrimerized aromatic polyimide has the following general structure:
  • R" comprises at least one of hydrogen, methyl, phenyl, or phthalic anhydride and R' comprises at least one of:
  • R comprises at least one of, acetylene, etyhynyl benzene, 3- phenyl-2-propynal, ethynyl phthalic anhydride, or propyne.
  • a separator for an electrochemical cell comprising nanoweb, the nanoweb comprising nanofibers of a cross-linked polyimide, wherein the cross-linked polyimide is derived from an aromatic dianhydride, an aromatic diamine, and a reactive end-capper.
  • the invention provides a multi-layer article for an electrochemical cell, the multi-layer article comprising:
  • a second electrode (b) a second electrode; and (c) a separator disposed between and in contact with the first electrode and the second electrode, the separator comprising: a nanoweb, the nanoweb comprising nanofibers of a cross-linked polyimide, wherein the cross-linked polyimide is derived from an aromatic dianhydride, an aromatic diamine, and a reactive end-capper.
  • the invention provides an electrochemical cell comprising:
  • a multilayer article comprising a first electrode, a second electrode in ionically conductive contact with the first electrode, and a separator disposed between and in contact with the first electrode and the second electrode, the separator comprising: a nanoweb, the nanoweb comprising nanofibers of a cross-linked polyimide, wherein the cross-linked polyimide is derived from an aromatic dianhydride, an aromatic diamine, and a reactive end-capper; (c) a first current collector in electrically conductive contact with the first electrode; and
  • Figure 1 schematically illustrates a cross-sectional view of a portion of a multilayer article, in accordance with various embodiments of the present invention.
  • Figure 2 shows a schematic illustration of a cross-sectional view of a portion of a multi-layer article, in accordance with various embodiments of the present invention.
  • Figure 3 schematically illustrates a perspective view of a multi-layer article in the form of a prismatic stack, in accordance with various embodiments of the present invention.
  • Figure 4 schematically illustrates a perspective view of a multi-layer article in the form of a spiral stack, in accordance with various embodiments of the present invention.
  • Figure 5 schematically illustrates a cross-sectional view of an electrochemical cell, in accordance with various embodiments of the present invention.
  • Figure 6 schematically illustrates a cross-sectional view of another
  • Figure 7 shows an infrared (IR) spectrum of a polyimide nanoweb derived from a polyamic acid having a stoichiometry of 97%.
  • Figure 8 shows an infrared (IR) spectrum of an exemplary polyimide nanoweb derived from a polyamic acid having a stoichiometry of 89%, the polyimide nanoweb comprising nanofibers of a cross-linked polyimide, in accordance with various embodiments of the present invention.
  • IR infrared
  • 300 multi-layer article in the form of a prismatic stack 400: multi-layer article in the form of a spiral stack 550, 650: electrochemical cell 600a, 600b, 600c: individual cells in an electrochemical cell
  • polyimide nanoweb comprising nanofibers of a cross-linked polyimide, wherein the cross-linked polyimide is derived from an aromatic dianhydride, an aromatic diamine, and a reactive end- capper.
  • nonwoven web refers to a nonwoven web
  • nanofibers constructed predominantly of nanofibers.
  • “Predominantly” means that greater than 50% by number, of the fibers in the web are nanofibers, where the term “nanofibers” as used herein refers to fibers having a number average diameter of less than 1000 nm, even less than 800 nm, even between 50 nm and 800 nm, and even between 100 nm and 400 nm. In the case of non-round cross-sectional nanofibers, the term “diameter” as used herein refers to the greatest cross- sectional dimension.
  • the nanoweb of the present invention can have greater than 70%, or 90% or it can even contain 100% of nanofibers.
  • a suitable polyimide nanoweb is characterized by a porosity in the range of 20-95% or 30-60%, as deternnined by measured basis weight and thickness in ASTM D3776 and D1777, respectively.
  • the polyimide is a fully aromatic polyimide.
  • Suitable aromatic dianhydrides include but are not limited to pyromellitic dianhydride (PMDA); biphenyltetracarboxylic dianhydride (BPDA); 3,3',4,4'- benzophenone tetracarboxylic dianhydride (BTDA); and mixtures thereof.
  • PMDA pyromellitic dianhydride
  • BPDA biphenyltetracarboxylic dianhydride
  • BTDA 3,3',4,4'- benzophenone tetracarboxylic dianhydride
  • Suitable aromatic diamines include but are not limited to oxydianiline (ODA); 1 ,3-bis(4-aminophenoxy)benzene (RODA); 1 ,4 phenylenediamine (PDA); and mixtures thereof.
  • ODA oxydianiline
  • RODA 1 ,3-bis(4-aminophenoxy)benzene
  • PDA 1 ,4 phenylenediamine
  • reactive end-capper is defined as a molecule which can be added to a polyamic acid at the end of the synthetic procedure, as shown in the reaction scheme (1 ) to react with free end groups, such as amines or anhydrides. Furthermore, the reactive end-capper must have an additional reactive functionality that can be activated via an external "trigger” mechanism, such as, thermal, UV exposure, or plasma treatment, to allow an increase in molecular weight of the polymer. Suitable classes of end-cappers include, but are not limited to, functionalized anhydrides and functionalized amines, functionalized with a reactive functionality selected from the group consisting of acetylene, vinyl, epoxide, nitrile, and ester.
  • Suitable reactive end-cappers include, but are not limited to a
  • the reactive end-capper is an acetylene-functionalized phthalic anhydride.
  • the acetylene-functionalized phthalic anhydride is selected from the group consisting of 4-phenylethynylphthalic anhydride (PEPA), ethynyl phthalic anhydride (EPA), pyromellitic ethynyl phthalic anhydride (PETA), methyl ethynyl phthalic anhydride (MEPA), and mixtures thereof.
  • the cross-linked polyimide is derived from pyromellitic dianhydride (PMDA), oxydianiline (ODA), and an acetylene-functionalized phthalic anhydride.
  • the cross-linked polyimide comprises a cyclotrimerized aromatic polyimide I.
  • the cyclotrimerized polyimide I has the following general structure:
  • R" comprises at least one of hydrogen, methyl, phenyl, or phthalic anhydride and R' comprises at least one of:
  • R comprises at least one of, acetylene, ethynyl benzene, 3- phenyl-2-propynal, ethynyl phthalic anhydride, or propyne.
  • the cross-linked polyimide comprises at least one of 1 ,3,5-tripolyimide benzene; 1 ,3,5-tripolyimide-2,4,6-triphenyl benzene; 1 ,3,5- tripolyimide-2,4,6-trimethyl benzene; 1 ,3,5-tripolyimide-2,4,6-(isobenzofuran-1 ,3- dione); or mixtures thereof.
  • the cross-linked polyimide is derived from an aromatic dianhydride, an aromatic diamine, and an acetylene- functionalized phthalic anhydride present in a molar ratio of 0.85:1 .0:0.30 to 0.95:1 .0: 0.01 or 0.88:1 .0:0.24 to 0.95:1 .0:0.02.
  • the resulting polyimide nanoweb has a break stress of at least 200 Kg/cm 2 or at least 330 Kg/cm 2 .
  • the nanofibers of the cross-linked polyimide of the present invention comprises more than 80 wt% of one or more fully aromatic polyimides, more than 90 wt% of one or more fully aromatic polyimides, more than 95 weight% of one or more fully aromatic polyimides, more than 99 wt% of one or more fully aromatic polyimides, more than 99.9 wt% of one or more fully aromatic polyimides, or 100 wt% of one or more fully aromatic polyimides.
  • the term "fully aromatic polyimide” refers specifically to polyimides in which at least 95% of the linkages between adjacent phenyl rings in the polymer backbone are effected either by a covalent bond or an ether linkage.
  • Up to 25%, preferably up to 20%, most preferably up to 10%, of the linkages can be effected by aliphatic carbon, sulfide, sulfone, phosphide, or phosphone functionalities or a combination thereof.
  • Up to 5% of the aromatic rings making up the polymer backbone can have ring substituents of aliphatic carbon, sulfide, sulfone, phosphide, or phosphone.
  • the fully aromatic polyimide suitable for use in the present contains no aliphatic carbon, sulfide, sulfone, phosphide, or phosphone.
  • the nanofibers may comprise 0.1-10 wt% of non fully-aromatic polyimides such as P84® polyimide available Evonik Industries (Lenzing, Austria); non fully-aromatic polymers from diaminodiphenyl methane as monomer, and/or other polymeric components such as polyolefins.
  • P84® polyimide is a condensation polymer of 2,4-diisocyanato-1 -methylbenzene and 1 - 1 '-methylenebis[4-isocyanatobenzene] with 5-5'carbonylbis[1 ,3- isobenzofurandione], having the following structure:
  • a method of making a polyimide nanoweb comprising reacting an aromatic dianhydride with an aromatic diamine to form a non end-capped polyamic acid; and adding a reactive end-capper to the non end-capped polyamic acid to form a reactive end-capped polyamic acid.
  • the method also comprises processing a solution of the reactive end-capped polyamic acid to form a polyamic acid nanoweb comprising nanofibers of the reactive end-capped polyamic acid; and thermally converting the polyamic acid nanoweb to a polyimide nanoweb comprising nanofibers of a cross-linked polyimide.
  • the method comprises reacting an aromatic compound having an aromatic group having an aromatic group having an aromatic group having an aromatic group having an aromatic group having an aromatic group having an aromatic group having an aromatic group having an aromatic group having an aromatic group having an aromatic group having an aromatic group having an aromatic group having an aromatic group having an aromatic group having an aromatic group having an aromatic group having an aromatic group having an aromatic group having an aromatic group having an aromatic group having an aromatic group having an aromatic group having an aromatic group having an aromatic group having an aromatic group
  • Suitable aromatic dianhydrides II include but are not limited to pyromellitic dianhydride (PMDA); biphenyltetracarboxylic dianhydride (BPDA); 3,3',4,4'- benzophenone tetracarboxylic dianhydride (BTDA); and mixtures thereof.
  • PMDA pyromellitic dianhydride
  • BPDA biphenyltetracarboxylic dianhydride
  • BTDA 3,3',4,4'- benzophenone tetracarboxylic dianhydride
  • Suitable aromatic diamines III include but are not limited to oxydianiline (ODA); 1 ,3-bis(4-aminophenoxy)benzene (RODA); 1 ,4 phenylenediamine (PDA); and mixtures thereof.
  • Any suitable aprotic polar solvent can be used in the synthesis of non end- capped polyamic acid IV, in the reaction scheme (1 ).
  • a suitable organic solvent acts as a solvent for the polyamic acid and at least one of the reactants.
  • a suitable solvent is inert to the reactants (the dianhydrides II or the diamines III).
  • the aprotic polar solvent is a solvent for the non end-capped polyamic acid IV and both the dianhydride II and the diamine III.
  • the normally liquid organic solvents of the ⁇ , ⁇ -dialkylcarboxylamide class are useful as solvents in the methof of this invention.
  • exemplary solvents include, but are not limited to, ⁇ , ⁇ -dimethylformamide (DMF) and ⁇ , ⁇ -dimethylacetamide (DMAC), N,N-diethylformamide, ⁇ , ⁇ -diethylacetamide, N,N-dimethylmethoxyacetamide, N-methyl-2-pyrrolidone (NMP), N-methylcaprolactam, and the like.
  • solvents which can be used in the present invention are: dimethylsulfoxide (DMSO), tetramethyl urea, pyridine, dimethylsulfone, hexamethylphosphoramide, tetramethylene sulfone, formamide, N-methylformamide, butyrolactone, and N- acetyl2-pyrrolidone.
  • DMSO dimethylsulfoxide
  • tetramethyl urea pyridine
  • dimethylsulfone hexamethylphosphoramide
  • tetramethylene sulfone formamide
  • N-methylformamide butyrolactone
  • N- acetyl2-pyrrolidone N- acetyl2-pyrrolidone.
  • the solvents can be used alone, in combinations of solvents, or in combination with poor solvents such as benzene, benzonitrile, dioxane, xylene, toluene, and cyclohexane.
  • the method of making a polyimide nanoweb further comprises adding a reactive end-capper to the non end-capped polyamic acid to form a reactive end- capped polyamic acid.
  • Suitable reactive end-cappers include, but are not limited to a
  • the method of making a polyimide nanoweb comprises adding an acetylene-functionalized phthalic anhydride V to the non end-capped polyamic acid IV to form an acetylene end-capped polyamic acid VI, as shown below in the reaction scheme (2).
  • the acetylene- functionalized phthalic anhydride V is a reactive end-capper that end-caps the polyamic acid IV with cross-linkable end-groups, such as acetylene.
  • R comprises at least one of, acetylene, ethynyl benzene, 3-phen propynal, ethynyl phthalic anhydride, propyne, as shown below and the like:
  • Suitable acetylene-functional ized phthalic anhydride V is selected from the group consisting of 5-ethynyl isobenzofuran-1 ,3-dione (EPA); phenylethynyl phthalic anhydride (PEPA); phenylethynyl trimellitic anhydride (PETA); methyl ethynyl phthalic anhydride (MEPA), and mixtures thereof.
  • EPA 5-ethynyl isobenzofuran-1 ,3-dione
  • PEPA phenylethynyl phthalic anhydride
  • PETA phenylethynyl trimellitic anhydride
  • MEPA methyl ethynyl phthalic anhydride
  • the molecular weight of the acetylene end-capped polyamic acid VI obtained from the reaction scheme (2) is dependent upon several factors, such as, purity of the monomers, relative amounts of aromatic anhydride and aromatic diamine, extent of moisture exclusion, choice of solvent, and maintenance of low to moderate temperatures.
  • Reaction (2) can be performed at temperatures up to 175 °C, but preferably at temperatures below 75 °C.
  • the temperature limitation results from three possible reactions which would limit molecular weight: (a) partial conversion to polyimide, releasing water which would hydrolyze the polyamic acid; (b) extensive conversion to polyimide above 100 °C, which, in addition to hydrolysis, could result in premature precipitation of low-molecular weight polymer out of the reaction medium; and (c) possible transamidation with the solvents.
  • Table 4 summarizes the effect of monomer stoichiometry on the molecular weight of the non end-capped polyamic acid.
  • the weight average molecular weight of the polyamic acid is also increased. Similar effect of monomer stoichiometry is expected for the acetylene end-capped polyamic acid.
  • the acetylene end-capped polyamic acid VI has a weight average molecular weight in the range of 2,000-50,000 g/mol or 4,000- 30,000 g/mol. In another embodiment, the acetylene end-capped polyamic acid VI has a weight average molecular weight of less than 12,000 g/mol.
  • the method of making a polyimide nanoweb further comprises processing a solution comprising 15-35 weight % of the acetylene end-capped polyamic acid VI to form a polyamic acid nanoweb comprising nanofibers of the acetylene end-capped polyamic acid VI.
  • the step of processing a solution of the acetylene end-capped polyamic acid comprises using at least one of electroblowing, electrospinning, or centrifugal spinning.
  • the acetylene end- capped polyamic acid VI is first prepared in solution; typical solvents are dimethylacetamide (DMAC) or dimethyformamide (DMF) which are also used as solvents for the monomers.
  • DMAC dimethylacetamide
  • DMF dimethyformamide
  • the solution for processing has 20-32 weight % of the acetylene end-capped polyamic acid VI.
  • One of the important parameters of solution spinning processes is viscosity of the solution, which can affect resultant fiber size and also the laydown of the nanofibers prior to forming a nanoweb.
  • the viscosity of the solution in turn is dependent upon the amount of acetylene end-capped polyamic acid VI in the solution which is related to the molecular weight of the acetylene end-capped polyamic acid VI, and which in turn also depends upon the stoichiometry, besides other factors.
  • Table 3 described infra shows that a 25 weight% solution comprising an acetylene end- capped polyamic acid having 93% stoichiometry has a lower viscosity than a 20 weight% solution comprising an acetylene end-capped polyamic acid having 97% stoichiometry (4.2 Pa s versus 8.4 Pa s).
  • the solution of the acetylene end-capped polyamic acid VI is formed into a nanoweb by
  • the solution of the acetylene end-capped polyamic acid is formed into a nanoweb by electrospinning as described in Huang et al., Adv. Mat. DOI:
  • At least 50% increase in nanoweb production is observed if a 30 weight% solution of the acetylene end-capped polyamic acid VI is used in solution spinning processes such as, electroblowing, electrospinning, or centrifugal spinning as compared to using a 20 weight% conventional polyamic acid, based solely on the increased polymer concentration.
  • the method of making a polyimide nanoweb also comprises converting the polyamic acid nanoweb comprising nanofibers of the reactive end-capped polyamic acid to a polyimide nanoweb comprising nanofibers of a cross-linked polyimide.
  • the step of converting the polyamic acid nanoweb to a polyimide nanoweb may be a multi-step process comprising imidization of the polyamic acid to polyimide and activation of the reactive functionalities of the reactive end- cappers. Any suitable method for activation of the reactive functionality of the reactive end-capper may be used, such as thermal treatment, UV exposure, and plasma treatment. Imidization of the polyamic acid to polyimide may be accomplished chemically or thermally.
  • the method comprises thermally converting the polyamic acid nanoweb comprising nanofibers of the acetylene end-capped polyamic acid VI to a polyimide nanoweb comprising nanofibers of a cross-linked polyimide, wherein the cross-linked polyimide comprises a cyclotrimerized aromatic polyimide I, as shown below in the reaction scheme (3). While not bound by any specific theory, it is believed that there are other possible reaction schemes for cross-linking, besides the cyclotrimerization shown here in the reaction scheme (3), such as, via formation of alkenyl esters, central arylene ethers, alkenyl imidate, and N-alkenyl amide.
  • R" comprises at least one of hydrogen, methyl, phenyl, or phthalic anhydride and R comprises at least one of acetylene, ethynyl benzene, 3-phenyl- 2-propynal, ethynyl phthalic anhydride, or propyne, as shown below:
  • R' comprises at least one of:
  • the step of thermally converting polyamic acid nanoweb to polyimide nanoweb is a two-step process.
  • the first step comprises imidizing the acetylene end-capped polyamic acid VI at 350 °C for 2-10 minutes to form an acetylene end-capped polyimide.
  • the second step comprises annealing the acetylene end-capped polyimide at 450 °C for 2-10 minutes to form a cross-linked polyimide comprising a cyclotrimerized aromatic polyimide I.
  • the cross-linked polyimide comprises a cyclotrimerized aromatic polyimide I with an aromatic ring being an anchor point of the trimer. This is evident by comparing infrared (IR) spectrum of a polyimide control formed without an end-capper with that of a cross-linked polyimide, as shown in Figures 7 and 8 respectively.
  • IR infrared
  • the intensity of the peak at 1 1 10 cm "1 which corresponds to the in-plane bending of para-substituted benzene rings decreases in intensity for the cross-lined polyimide, as compared to that of control polyimide.
  • Comparing Figures 7 and 8 shows that the peak height ratio of the peak at 1 1 10 cm “1 to a control background peak at 1500 cm “1 is decreased by approximately 30% in the spectrum of the cross-linked polyimide shown in Figure 8 compared to the control polyimide shown in Figure 7.
  • a peak at 700 cm “1 which is representative of ring bending for 1 ,3,5 substituted aromatics is developed as a shoulder in the spectrum of the cross-linked polyimide.
  • the peak height ratio of this shoulder increases by approximately 50% in the spectrum of cross-linked polyimide as shown in Figure 8 compared to control polyimide shown in Figure 7.
  • the step of thermally converting the polyamic acid nanoweb to a polyimide nanoweb can be performed using any suitable technique, such as, heating in a convection oven, vacuum oven, infra-red oven in air or in inert atmosphere such as argon or nitrogen.
  • the polyamic acid nanoweb is heated in a multi-zone infra-red oven with each zone set to a different temperature. In an alternative embodiment, all the zones are set to the same temperature. In another embodiment the infrared oven further comprises an infra-red heater above and below a conveyor belt. It should be noted that the temperature of each zone is determined by the particular polyamic acid, time of exposure, fiber diameter, emitter to emitter distance, residual solvent content, purge air temperature and flow, fiber web basis weight (basis weight is the weight of the material in grams per square meter). For example, conventional annealing range is 400-500 °C for PMDA/ODA, but is around 200 °C for BPDA/RODA; BPDA/RODA will
  • the nanofibers of a cross-linked polyimide of this invention comprise more than 80 weight% of one or more fully aromatic polyimides, more than 90 weight% of one or more fully aromatic polyimides, more than 95 weight% of one or more fully aromatic polyimides, more than 99 weight% of one or more fully aromatic polyimides, more than 99.9 weight% of one or more fully aromatic polyimides, or 100 weight% of one or more fully aromatic polyimides.
  • the term "fully aromatic polyimide” refers specifically to polyimides in which the ratio of the imide C-N infrared absorbance at 1375 cm “1 to the p-substituted C-H infrared absorbance at 1500 cm "1 is greater than 0.51 and wherein at least 95% of the linkages between adjacent phenyl rings in the polymer backbone are effected either by a covalent bond or an ether linkage. Up to 25%, preferably up to 20%, most preferably up to 10%, of the linkages can be effected by aliphatic carbon, sulfide, sulfone, phosphide, or phosphone functionalities or a combination thereof.
  • the aromatic rings making up the polymer backbone can have ring substituents of aliphatic carbon, sulfide, sulfone, phosphide, or phosphone.
  • the fully aromatic polyimide suitable for use in the present contains no aliphatic carbon, sulfide, sulfone, phosphide, or phosphone.
  • Aromatic polyimide nanowebs of the present invention are suitable for use as separators for electrochemical cells, liquid and air filters, and thermal insulation materials.
  • Polyimide nanowebs are an excellent choice for high flux, high filtration efficiency applications due to relatively small pores and high porosity.
  • polyimide nanowebs provide many benefits when used as separators for electrochemical cells including, but not limited to, high-temperature stability and a suitable critical surface tension due to polymer surface energy and nonwoven morphology, which enables wetting with organic electrolyte solutions such as LiPF 6 in ethylene carbonate/ethyl methyl carbonate.
  • a separator for an electrochemical cell comprising a nanoweb disclosed herein above, the nanoweb comprising nanofibers of a cross- linked polyimide, wherein the cross-linked polyimide is derived from an aromatic dianhydride, an aromatic diamine, and a reactive end-capper.
  • the reactive end-capper is an acetylene-functionalized phthalic anhydride selected from the group consisting of 4-phenylethynylphthalic anhydride (PEPA), ethynyl phthalic anhydride (EPA), pyromellitic ethynyl phthalic anhydride (PETA), methyl ethynyl phthalic anhydride (MEPA), and mixtures thereof.
  • PEPA 4-phenylethynylphthalic anhydride
  • EPA ethynyl phthalic anhydride
  • PETA pyromellitic ethynyl phthalic anhydride
  • MEPA methyl ethynyl phthalic anhydride
  • the separator for an electrochemical cell comprises a nanoweb disclosed herein above, the nanoweb comprising nanofibers of a cross-linked polyimide, wherein the cross-linked polyimide comprises a cyclotrimerized aromatic polyimide I, and wherein the cross-linked polyimide is derived from an aromatic dianhydride II, an aromatic diamine III, and an acetylene-functionalized phthalic anhydride IV.
  • a multi-layer article comprising a first electrode, a second electrode, and a separator disposed between and in contact with the first electrode and the second electrode, the separator comprising a nanoweb disclosed herein above, the nanoweb comprising nanofibers of a cross- linked polyimide, wherein the cross-linked polyimide is derived from an aromatic dianhydride II, an aromatic diamine III, and a reactive end-capper IV.
  • a multi-layer article comprising a first electrode, a second electrode, and a separator disposed between and in contact with the first electrode and the second electrode, the separator comprising a nanoweb disclosed herein above, the nanoweb comprising nanofibers of a cross- linked polyimide, wherein the cross-linked polyimide comprises a cyclotrimerized aromatic polyimide I, wherein the cross-linked polyimide is derived from an aromatic dianhydride II, an aromatic diamine III, and an acetylene-functionalized phthalic anhydride IV.
  • FIG. 1 schematically illustrates a cross-sectional view of a portion of a multi-layer article, 100, in accordance with an embodiment of the present invention.
  • the multi-layer article, 100 comprises a first electrode, 101 , a second electrode, 102, and a separator, 105 disposed between and in contact with the first electrode, 101 and the second electrode, 102.
  • the separator, 105 is
  • the cross-linked polyimide comprises a cyclotrimerized aromatic polyimide I.
  • FIG. 2 schematically illustrates a cross-sectional view of a portion of another embodiment of a multi-layer article, 200.
  • the multi-layer article, 200 comprises a first electrode, 201 ; a first current collector, 211 in electrically conductive contact with the first electrode, 201 ; a second electrode, 202; a second current collector, 212 in electrically conductive contact with the second electrode, 202, and a separator, 205 disposed between and in contact with the first electrode, 201 and the second electrode, 202.
  • the separator, 205 disposed between and in contact with the first electrode, 201 and the second electrode, 202.
  • the cross-linked polyimide comprises a cyclotrimerized aromatic polyimide I.
  • the nanofibers, 106 are characterized by a number average diameter of less than 1000 nm. In an embodiment, the nanofibers, 106 are characterized by a number average diameter in the range of 50-800 nm. In a further embodiment, the nanofibers, 106 are characterized by a number average diameter in the range of 100-400 nm.
  • the polyimide is a fully aromatic polyimide. In a further embodiment, the fully aromatic polyimide is derived from PMDA, ODA, and an acetylene-functionalized phthalic anhydride.
  • the first electrode, 101 , 201 and the second electrode, 102, 202 have different material composition in an embodiment, and the multi- layer article 100, 200 hereof is useful in batteries, such as lithium-ion battery.
  • the first electrode, 101 , 201 and the second electrode, 102, 202 have the same material composition, and the multi-layer article 100, 200 hereof is useful in lithium-ion capacitors, particularly in that class of capacitors known as "electric double layer capacitors.”
  • the first electrode, 101 , 201 comprises at least one of carbon, graphite, coke, lithium titanates, lithium-tin alloys, silicon, carbon-silicon composites, or mixtures thereof.
  • the second electrode, 102, 202 comprises at least one of lithium cobalt oxide, lithium iron phosphate, lithium nickel oxide, lithium manganese phosphate, lithium cobalt phosphate, Li(Mni/3 Nii 3 Coi 3)O 2 (MNC), Li(Nii -y-z Co y Al z )O 2 (NCA), lithium manganese oxide, or mixtures thereof.
  • the first electrode, 101 , 201 ; the separator, 105, 205; and the second electrode, 102, 202 are in mutually adhering contact in the form of a laminate.
  • each electrode material is combined with one or more polymers and other additives to form a paste that is adheringly applied to a surface of the nanoweb separator, 105, 205 having two opposing surfaces. Pressure and/or heat can be applied to form an adhering laminate.
  • the electrode is coated onto a non-porous metallic sheet that serves as a current collector. In a preferred embodiment, both electrodes are so coated.
  • the metallic current collectors comprise different metals.
  • the metallic current collectors comprise the same metal.
  • the metallic current collectors suitable for use in the present invention are preferably metal foils.
  • the first electrode, 201 is a negative electrode material comprising graphite, an intercalating material for Li ions;
  • the second electrode, 202 is a positive electrode material comprising lithium cobalt oxide;
  • the separator 205 comprising a nanoweb comprising nanofibers of a cross-linked polyimide, disclosed herein above.
  • the multi-layer article, 200 comprises a first current collector, 211 comprising a copper foil in electrically conductive contact with the first electrode, 201 ; and a second current collector, 212 comprising an aluminum foil in electrically conductive contact with the second electrode, 201.
  • Figure 3 schematic illustrates a perspective view of another embodiment of a multi-layer article, 300 of the present invention in the form of a prismatic stack.
  • Figure 4 schematic illustrates a perspective view of another embodiment of a multi-layer article, 400 of the present invention in the form of a spiral stack.
  • the multi-layer article, 300, 400 comprise a first layer, 311 , 411 comprising a first negative current collector; a second layer, 301 , 401 comprising a first negative electrode in electrically conductive contact with the first layer, 311 , 411 ; a third layer, 305, 405 comprising a first separator of the present invention; a fourth layer, 302, 402 comprising a first positive electrode in contact with the third layer; a fifth layer, 312, 412 comprising a first positive current collector in electrically conductive contact with the fourth layer, 302, 402; a sixth layer, 302', 402' comprising a second positive electrode in electrically conductive contact with the fifth layer, 312, 412; a seventh layer, 305', 405' comprising a second separator of the present invention in contact with the sixth layer, 302', 402'; an eighth layer, 301 ', 401 ' comprising a second negative electrode in contact with the seventh layer, 305', 405'.
  • FIG. 5 schematically illustrates a cross-sectional view of an embodiment of an electrochemical cell, 550.
  • the electrochemical cell, 550 comprises a housing, 510 having disposed therewithin, an electrolyte, 515, and a multi-layer article 500 at least partially immersed in the electrolyte, 515.
  • the multi-layer article, 500 comprising a first electrode, 501 , a second electrode, 502, and a separator, 505 as disclosed hereinabove, disposed between and in contact with the first electrode, 501 and the second electrode, 502 and wherein the first electrode, 501 and the second electrode, 502 are in ionically conductive contact with the electrolyte, 515.
  • the electrochemical cell, 550 also comprises a first current collector, 511 in electrically conductive contact with the first electrode, 501 and a second current collector, 512 in electrically conductive contact with the second electrode, 502.
  • the first current collector, 511 comprises a copper foil; the first electrode, 501 comprising graphite is in adhering contact with the copper foil; the separator 505 comprising a nanoweb comprising nanofibers of a cross-linked polyimide, disclosed herein above; the second electrode, 502 comprising lithium cobalt oxide is in adhering contact with the nanoweb of the separator, 505; and the second current collector, 512 comprising an aluminum foil is in adhering contact with lithium cobalt oxide.
  • the electrolyte, 515 is a liquid electrolyte comprising an organic solvent and a lithium salt soluble therein.
  • the lithium salt is LiPF 6 , LiBF 4 , or LiCIO .
  • the organic solvent comprises one or more alkyl carbonates.
  • the one or more alkyl carbonates comprises a mixture of ethylene carbonate and dimethylcarbonate.
  • the optimum range of salt and solvent concentrations may vary according to specific materials being employed, and the anticipated conditions of use; for example, according to the intended operating temperature.
  • the solvent is 70 parts by volume ethylene carbonate and 30 parts by volume dimethyl carbonate and the salt is LiPF 6 .
  • the electrolyte, 515 may comprise a lithium salt such as, lithium hexafluoroarsenate, lithium bis-trifluoromethyl sulfonamide, lithium bis(oxalate)boronate, lithium difluorooxalatoboronate, or the Li + salt of
  • the electrolyte, 515 may comprise a solvent, such as, propylene carbonate, esters, ethers, or trimethylsilane derivatives of ethylene glycol or poly(ethylene glycols) or combinations of these.
  • the electrolyte, 515 may contain various additives known to enhance the performance or stability of Li-ion batteries, as reviewed for example by K. Xu in Chem. Rev., 104, 4303 (2004), and S.S. Zhang in J. Power Sources, 162, 1379 (2006).
  • Also present in the electrochemical cell, 550, but not shown, would be a means for connecting the cell to an outside electrical load or charging means. Suitable means include wires, tabs, connectors, plugs, clamps, and any other such means commonly used for making electrical connections.
  • FIG. 6 schematically illustrates a cross-sectional view of another embodiment of an electrochemical cell, 650 of the present invention.
  • the electrochemical cell 650 comprises a stack of three multi-layer articles, 600a, 600b, 600c and an electrolyte, 615 disposed in a housing, 610.
  • the electrochemical cell 650 comprises a first negative current collector, 611 ; a first negative electrode, 601 in electrically conductive contact with the first negative current collector, 611 ; a first separator, 605 of the present invention; a first positive electrode, 602 in contact with the first separator, 605, wherein the first positive electrode, 602 is in ionically conductive contact with the first negative electrode, 601 ; a first positive current collector, 612 in electrically conductive contact with the first positive electrode, 602; a second positive electrode, 602' in electrically conductive contact with the first positive current collector, 612; a second separator, 605' of the present invention, in contact with the second positive electrode 602'; a second negative electrode, 601 ' in contact with the second separator, 605', wherein the second negative electrode, 601' is in ionically conductive contact with the second positive electrode, 602'; and so on, repeating one or more layers from the first negative current collector, 611 , such that a first negative
  • the output voltage from the stack is equal to the combined voltage from each cell.
  • the individual cells, 600a, 600b, 600c making up the multi-layer stack, 600 are electrically connected in parallel, the output voltage from the stack is equal to the voltage of one cell.
  • the average practitioner of the electrical art will know when a series arrangement is appropriate, and when a parallel.
  • the positive and negative electrodes in lithium-ion cells suitable for use in one embodiment of the present invention are similar in form to one another and are made by similar processes on similar or identical equipment.
  • active material is coated onto both sides of a metallic foil, preferably Al foil or Cu foil, which acts as current collector, conducting the current in and out of the cell.
  • the negative electrode is made by coating graphitic carbon on copper foil.
  • the positive electrode is made by coating a lithium metal oxide (e.g. UC0O 2 ) on Al foil.
  • the thus coated foils are wound on large reels and are dried at a temperature in the range of 100-150 °C before bringing them inside a dry room for cell fabrication. The electrode thickness achieved after drying is typically in the range of
  • the one-side coated foil is fed back into the coating machine with the uncoated side disposed to receive the slurry deposition to produce a coating on both sides of the foil.
  • the electrodes so formed are then calendered and optionally slit to narrow strips for different size batteries. Any burrs on the edges of the foil strips could give rise to internal short circuits in the cells so the slitting machine must be very precisely manufactured and maintained.
  • Lithium-ion batteries are available in a variety of forms including
  • Lithium-ion batteries find use in a variety of different applications (e.g. consumer electronics, power tools, and hybrid electric vehicles).
  • the manufacturing process for lithium-ion batteries is similar to that of other batteries such as NiCd and NiMH, but is more sensitive because of the reactivity of the materials used in lithium-ion batteries.
  • the electrochemical cell, 550, 650 comprises the multi- layer article, 500, 600 in the form of a prismatic stack, for example, multi-layer article, 300 in prismatic form, as shown in the Figure 3.
  • the electrochemical cell, 550, 650 comprises the multi-layer article, 500, 600 in the form of a spiral stack, for example, multi-layer article, 400 in spiral form, as shown in the Figure 4.
  • the electrode assembly is first wound into a spiral structure as depicted in Figure 4. Then, a tab is applied to the edge of the electrode to connect the electrode to its corresponding terminal.
  • the tabs are then welded to the can and the spirally wound electrode assembly is inserted into a cylindrical housing.
  • the housing is then sealed but leaving an opening for injecting the electrolyte into the housing.
  • the cells are then filled with electrolyte and then sealed.
  • the electrolyte is usually a mixture of salt (LiPF 6 ) and carbonate based solvents.
  • Cell assembly is preferably carried out in a "dry room” since the electrolyte reacts with water. Moisture can lead to hydrolysis of LiPF 6 forming HF, which can degrade the electrodes and adversely affect the cell performance.
  • the cell After the cell is assembled it is formed (conditioned) by going through at least one precisely controlled charge/discharge cycle to activate the working materials. For most lithium-ion chemistries, this involves creating the SEI (solid electrolyte interface) layer on the negative (carbon) electrode. This is a passivating layer which is essential to protect the lithiated carbon from further reaction with the electrolyte.
  • SEI solid electrolyte interface
  • the invention provides an electrochemical double layer capacitor (EDLC).
  • EDLCs are energy storage devices having a capacitance that can be as high as several Farads. Charge storage in double layer
  • electrochemical capacitors is a surface phenomenon that occurs at the interface between the electrodes, typically carbon, and the electrolyte.
  • the polyimide nanoweb hereof serves as a separator that absorbs and retains the electrolyte thereby maintaining close contact between the electrolyte and the electrodes.
  • the role of the polyimide nanoweb hereof as the separator is to electrically insulate the positive electrode from the negative electrode and to facilitate the transfer of ions in the electrolyte, during charging and discharging.
  • Electrochemical double layer capacitors are typically made in a cylindrically wound design in which the two carbon electrodes and separators are wound together, the polyimide nanoweb separators having high strength avoid short circuits between the two electrodes.
  • PAA-AC-5 PETA 1.0 0.88 0.12 29 10.9
  • Table 4 shows effect of monomer stoichiometry, as it is changed from 93% to 98% on the molecular weight of the non end-capped polyamic acid formed. After reacting for 16 hrs and prior to end-capping, solution aliquots were transferred to scintillation vials and their molecular weight was determined by GPC. As used herein, the term "93% stoichiometry" refers to the amount of PMDA relative to ODA. Thus, a polyamic acid having a 93% stoichiometry was made using PMDA and ODA in the amounts of PMDA:ODA:: 0.93:1 .
  • PAA-AC- NW acetylene end-capped Polyamic acid nanoweb
  • Acetylene end-capped polyamic acid nanoweb (PAA-AC-NW) prepared supra were imidized at 350 °C and annealed at 450 °C in a convection oven under air atmosphere at various times, as given in Table 4 to form acetylene end- capped polyimide nanoweb (PI-AC-NW).
  • each sample was cut into 1 .27 cm by 12.7 cm (0.5" by 5") strips and tested for break load, according to ISO 9073-3, using an Instron machine. Samples were loaded into the Instron machine and pulled with a crosshead speed of ten inches per minute. Stress-strain curves were analyzed for break load, which was converted into break stress by dividing by the cross- sectional area of each sample. The thickness of each sample was measured with a Mitutoyo Digimatic (Series 293) Micrometer. The Break stress data reported in Table 5 represents mean of at least three sample runs.
  • Table 5 shows that imidization and annealing protocols have a significant impact on the strength of polyimide nanowebs which were end-capped with cross-linkable groups. Comparing PI-AC-NW-1 -1 with PI-AC-NW-1 -2 shows that upon addition of an annealing step (450 °C for 5 min) to the imidization step (350 °C for 2 min), the break stress of the sample increased by 300%.
  • the cross-link points become 1 ,3,5 trisubstituted benzene rings, which do not absorb in this region.
  • the peak height ratio of this peak to a control background peak at 1500 cm "1 decreases by approximately 30% in the spectrum of PI-AC- NW-3 compared to PI-Control-1 .
  • a peak at 700 cm- 1 (which is representative of ring bending for 1 ,3,5 substituted aromatics) develops as a shoulder in the spectrum of PI-AC-NW-3.
  • the peak height ratio of this shoulder (compared to the background peak at 1500 cm "1 ) increased by approximately 50% in the spectrum of PI-AC-NW-3 compared to PI-Control-1 .
  • Li-ion coin cells (CR2032) were assembled to evaluate the cell
  • the anode comprised natural graphite coated on Cu and cathode comprised a layer of LiCoO 2 coated on Al foil, both obtained from Pred Materials International (New York, NY).
  • the electrolyte comprised 1 Molar LiPF 6 in a 70:30 mixture of ethyl methyl carbonate and ethylene carbonate obtained from Ferro Corporation (Cleveland, OH).
  • the cell can was obtained from Farasis Energy, Inc (Hayward, CA).
  • the anode and the cathode were separated by a single layer of cross-linked polyimide nanoweb of Example PI-AC-NW-1 -2 (stoichiometry 93%) and of Example PI-AC-NW-4 (stoichiometry 89%).
  • Another Li-ion coin cell for comparison was made with the anode and the cathode separated by a single layer of control sample PI-Control-1 (stoichiometry 97%) formed from polyamic acid without an end-capper (PAA-1 ).
  • the as-prepared Li-ion coin cells containing either a single layer of cross- linked polyimide nanoweb separator (PI-AC-NW-1 -2 or PI-AC-NW-4) or a single layer control sample PI-Control-1 were attached to a battery tester, Series 4000 (Maccor Inc., Tulsa, OK).
  • Table 6 shows that within experimental error, the cross-linked polyimide separator performed equivalently to the polyimide control sample formed from polyamic acid without an end-capper.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Macromolecular Compounds Obtained By Forming Nitrogen-Containing Linkages In General (AREA)

Abstract

L'invention concerne une cellule électrochimique qui comprend un électrolyte et un article multicouche, l'article multicouche contenant une première électrode, une seconde électrode en contact ioniquement conducteur avec la première électrode et un séparateur placé entre la première électrode et la seconde électrode et en contact avec elles. Le séparateur comporte un nanoréseau, qui comprend des nanofibres d'un polyimide réticulé, le polyimide réticulé étant dérivé d'un dianhydride aromatique, d'une diamine aromatique et d'une coiffe d'extrémité réactive. La coiffe d'extrémité réactive est au moins l'un d'un anhydride fonctionnalisé ou d'une amine fonctionnalisée, fonctionnalisé avec une fonctionnalité réactive choisie parmi le groupe constitué par un acétylène, un vinyle, un époxyde, un nitrile et un ester. La cellule électrochimique comprend en outre un premier collecteur de courant en contact électriquement conducteur avec la première électrode et un second collecteur de courant en contact électriquement conducteur avec la seconde électrode.
PCT/US2013/043256 2012-06-01 2013-05-30 Cellule électrochimique comprenant un nanoréseau contenant des nanofibres d'un polyimide réticulé WO2013181333A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US201261654106P 2012-06-01 2012-06-01
US61/654,106 2012-06-01

Publications (1)

Publication Number Publication Date
WO2013181333A1 true WO2013181333A1 (fr) 2013-12-05

Family

ID=48577955

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2013/043256 WO2013181333A1 (fr) 2012-06-01 2013-05-30 Cellule électrochimique comprenant un nanoréseau contenant des nanofibres d'un polyimide réticulé

Country Status (1)

Country Link
WO (1) WO2013181333A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110112354A (zh) * 2018-02-01 2019-08-09 东京应化工业株式会社 二次电池及二次电池用多孔质隔膜
CN117089315A (zh) * 2023-10-19 2023-11-21 宁波长阳科技股份有限公司 一种水性锂电池聚酰亚胺粘合剂及制备方法、锂电池极片

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1514888A1 (fr) * 2003-09-02 2005-03-16 I.S.T. (MA) Corporation résines polyimides pouvant être utilisées pour des moulages par des résines de transfert et d'infusion de résine
US20050067732A1 (en) 2002-03-26 2005-03-31 Yong Min Kim Manufacturing device and the method of preparing for the nanofibers via electro-blown spinning process
US20110143217A1 (en) * 2009-12-15 2011-06-16 E. I. Du Pont De Nemours And Company Electrochemical cell comprising a separator comprising a nanoweb consisting essentially of nanofibers of fully aromatic polyimide
WO2012047960A2 (fr) * 2010-10-07 2012-04-12 E.I. Du Pont De Nemours And Company Conversion thermique rapide de fibre de poly(acide amique) en fibre de polyimide

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050067732A1 (en) 2002-03-26 2005-03-31 Yong Min Kim Manufacturing device and the method of preparing for the nanofibers via electro-blown spinning process
EP1514888A1 (fr) * 2003-09-02 2005-03-16 I.S.T. (MA) Corporation résines polyimides pouvant être utilisées pour des moulages par des résines de transfert et d'infusion de résine
US7129318B2 (en) 2003-09-02 2006-10-31 I.S.T. (Ma) Corporation RTM and RI processable polyimide resins
US20110143217A1 (en) * 2009-12-15 2011-06-16 E. I. Du Pont De Nemours And Company Electrochemical cell comprising a separator comprising a nanoweb consisting essentially of nanofibers of fully aromatic polyimide
WO2012047960A2 (fr) * 2010-10-07 2012-04-12 E.I. Du Pont De Nemours And Company Conversion thermique rapide de fibre de poly(acide amique) en fibre de polyimide

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
HUANG ET AL., ADV. MAT.
K. XU, CHEM. REV., vol. 104, 2004, pages 4303
S.S. ZHANG, J. POWER SOURCES, vol. 162, 2006, pages 1379

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110112354A (zh) * 2018-02-01 2019-08-09 东京应化工业株式会社 二次电池及二次电池用多孔质隔膜
CN117089315A (zh) * 2023-10-19 2023-11-21 宁波长阳科技股份有限公司 一种水性锂电池聚酰亚胺粘合剂及制备方法、锂电池极片
CN117089315B (zh) * 2023-10-19 2024-02-09 宁波长阳科技股份有限公司 一种水性锂电池聚酰亚胺粘合剂及制备方法、锂电池极片

Similar Documents

Publication Publication Date Title
EP2649228B1 (fr) Nanoréseau polyimide présentant une surface amidisée et son procédé de préparation
EP2514003B1 (fr) Article multicouche à nanobande en polyimide
US20110143217A1 (en) Electrochemical cell comprising a separator comprising a nanoweb consisting essentially of nanofibers of fully aromatic polyimide
EP2513366B1 (fr) Procédé d'augmentation de la solidité et de la résistance aux solvants de nanobandes en polyimide
US20190245177A1 (en) Polyimide web separator for use in an electrochemical cell
US20120148896A1 (en) Multi-layer article of polyimide nanoweb with amidized surface
US20140356703A1 (en) Electrochemical cell comprising a nanoweb comprising nanofibers of a cross-linked polyimide
US9475009B2 (en) Filtration method using polyimide nanoweb with amidized surface and apparatus therefor
KR20180075520A (ko) 축전 소자 전극용 폴리이미드 용액, 축전 소자 전극의 제조 방법 및 축전 소자 전극
WO2013075089A1 (fr) Procédé pour réduire la décharge spontanée dans une cellule électrochimique
WO2012078607A1 (fr) Élément électrochimique comprenant un article multicouche de nanotoile de polyimide à surface amidique
WO2013181333A1 (fr) Cellule électrochimique comprenant un nanoréseau contenant des nanofibres d'un polyimide réticulé
EP2727170A1 (fr) Nanobande en polyimide améliorée

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 13727786

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 13727786

Country of ref document: EP

Kind code of ref document: A1