Dry, Crumbleable Fluoropolymer Aggregate Composition for Use as a Binder in Lithium-Ion Secondary Battery Electrodes

Abstract

Fluoropolymer compositions for use as binders in lithium-ion secondary battery electrodes, as well as methods for their manufacture, and electrode compositions and lithium-ion secondary batteries utilizing the same are described. The fluoropolymer compositions are dry, disintegrable aggregates produced by co-coagulation of an aqueous dispersion of a first tetrafluoroethylene polymer having a melt creep viscosity of at least about 0.5 x 10 poise and a second polymer different from the first polymer. These fluoropolymer compositions provide lithium-ion secondary batteries with improved performance, such as improved electrode loading and PTFE binder stability in the anode, resulting in lithium-ion secondary batteries with improved performance, such as improved capacity retention and improved reversible capacity retention.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 411,777, filed September 30, 2022, the entire disclosure of which is incorporated herein by reference.

[0002] FIELD OF THE INVENTION The present disclosure relates to dry, disintegrable fluoropolymer aggregate compositions for use as binders in lithium-ion secondary battery electrodes, dry processes for making such compositions, electrode compositions and electrodes, and lithium-ion batteries utilizing such electrodes. [Background technology]

[0003] Significant industry efforts have been made to explore lithium-ion secondary battery electrode compositions and viable electrode manufacturing processes with the aim of improving battery performance. However, many methods either have complicated manufacturing procedures or are limited to laboratory-scale processing, and many currently commercially available electrode compositions suffer from relatively poor performance for real-world large-scale adoption and practicality. Many existing lithium-ion battery electrode manufacturing methods involve slurry technology that utilizes NMP (N-methylpyrrolidone) as a solvent, which is toxic and requires expensive solvent recycling equipment, making slurry-based fabrication processes costly and undesirable.

[0004] Unlike the above-mentioned methods based on solvents such as NMP, fabrication using binder fibrillation is a dry process, and fibrillizable polytetrafluoroethylene (PTFE) is a known binder utilized. In this process, PTFE particles are shear-mixed and, under these conditions, form cohesive fibrils that can bind electrode active materials even at relatively low binder contents, and such dry electrodes have attracted growing industrial interest. Compared to solvent-slurry-based methods, this dry process has the potential to fabricate roll-to-roll electrodes with unlimited thickness and minimal cracking. More importantly, the elimination of toxic NMP and solvent recycling equipment makes the dry process a cost-effective and environmentally friendly electrode manufacturing strategy.

[0005] The large-scale adoption and commercial use of PTFE-based lithium-ion secondary battery electrode binders has been hindered by certain drawbacks of PTFE, including, among others, the difficulty of formulating PTFE into electrode compositions at the appropriate PTFE particle size to substantially match the particle size of the electrode active material without the PTFE prematurely fibrillating to form electrode compositions with non-uniform particle size distributions, and the relative instability of PTFE (as compared to the current slurry-based commercial binder PVDF) to reduction under lithium-ion battery anode operating conditions. Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention addresses certain shortcomings of prior work in this field by providing dry, disintegrable fluoropolymer aggregate compositions useful for electrode binders based on co-coagulated tetrafluoroethylene polymer and a second polymer composition, electrode binder compositions, methods for their preparation, and lithium-ion secondary batteries utilizing them. The compositions provide lithium-ion secondary batteries with improved performance over the prior art. For example, the binder compositions have the potential to positively impact electrode loading and the stability of the PTFE binder in the electrode (especially the anode), resulting in lithium-ion secondary batteries with improved capacity retention and improved reversible capacity retention. [Means for solving the problem]

[0007] For purposes of summarizing the invention and the advantages achieved over the prior art, certain objects and advantages of the invention are described herein. Not all such objects or advantages may be achieved in any particular embodiment of the invention. Thus, for example, one skilled in the art will recognize that the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein, without necessarily achieving other objects or advantages that may be taught or suggested herein.

[0008] The present invention, in one embodiment, provides: i.) at least about 0.5×10 11 The shortcomings of prior work in the field are addressed by providing a fluoropolymer composition for use as a binder in a lithium ion secondary battery electrode, comprising a dry, friable agglomerate comprising: ii.) a first polymer comprising a tetrafluoroethylene polymer having a melt creep viscosity in poise; and ii.) a second polymer different from the first polymer.

[0009] In another embodiment, there is provided a method for producing an electrode composition for use in a lithium ion secondary battery electrode, comprising: IV.) mixing electrode active particles into a dried, friable agglomerate, the dried, friable agglomerate comprising: i.) at least about 0.5×10 11and ii.) grinding together dried, friable agglomerates comprising a first polymer comprising a non-fibrillated tetrafluoroethylene polymer having a melt creep viscosity of 100 poise, and ii.) a second polymer different from the first polymer, to form an electrode composition comprising fibrillated tetrafluoroethylene polymer. Also provided is a method for forming an electrode composition comprising fibrillated tetrafluoroethylene polymer, the method comprising: (i) grinding together dried, friable agglomerates comprising a first polymer comprising a non-fibrillated tetrafluoroethylene polymer having a melt creep viscosity of 100 poise, and ii.) a second polymer different from the first polymer, to form an electrode composition comprising fibrillated tetrafluoroethylene polymer. Also provided is a method for forming an electrode composition comprising fibrillated tetrafluoroethylene polymer, the method comprising: (i.) grinding together dried, friable agglomerates comprising a first polymer comprising a non-fibrillated tetrafluoroethylene polymer having a melt creep viscosity of 100 poise, and ii ... grinding together dried, friable agglomerates comprising a second polymer different from the first polymer, the second polymer being different from the first polymer, to form an electrode composition comprising fibrillated tetrafluoroethylene polymer. 11 Also included is a method for forming dried, disintegrable agglomerates comprising particles of a first polymer and a second polymer by carrying out the steps of co-coagulating an aqueous dispersion of a first polymer comprising a non-fibrillating tetrafluoroethylene polymer having a melt creep viscosity of poise with I.-ii) a second polymer different from the first polymer to produce disintegrable agglomerates of the first polymer and the second polymer, II.) separating the disintegrable agglomerates from the aqueous phase, and III.) drying the disintegrable agglomerates.

[0010] In another embodiment, a composition for use in a lithium ion secondary battery cathode film comprises: i.) cathode active particles comprising a lithium transition metal oxide; ii.) conductive carbon; and iii.) at least about 0.5×10 11 and a fluoropolymer binder comprising a mixture of particles of a tetrafluoroethylene polymer having a melt creep viscosity of poise and particles of a second polymer, wherein the tetrafluoroethylene polymer is fibrillated.

[0011] In another embodiment, a composition for use in a lithium ion secondary battery anode film comprises: i.) anode active particles; and iii.) at least about 0.5×10 11 and a fluoropolymer binder comprising a mixture of particles of a tetrafluoroethylene polymer having a melt creep viscosity of poise and particles of a second polymer, wherein the tetrafluoroethylene polymer is fibrillated.

[0012] In another embodiment, a lithium ion secondary battery includes a cathode comprising: 1) a cathode electrode layer adhered to a metal current collector, the cathode electrode layer comprising a cathode electrode composition, the cathode electrode composition comprising: a) cathode active particles comprising a lithium transition metal oxide; b) conductive carbon; and c) a fluoropolymer binder; 11 A lithium ion secondary battery is provided, comprising: 1) a cathode comprising a fluoropolymer binder containing a mixture of particles of a tetrafluoroethylene polymer having a melt creep viscosity of poise and ii) particles of a second polymer; 2) an anode; 3) a separator between the cathode and the anode; and 4) an electrolyte in communication with the cathode, anode, and separator.

[0013] In another embodiment, a lithium-ion secondary battery includes an anode comprising: 1) an anode electrode layer affixed to a metal current collector, the anode electrode layer comprising an anode electrode composition comprising: a) anode active particles; and b) a fluoropolymer binder, the anode electrode composition comprising: i) at least about 0.5×10 11 A lithium ion secondary battery is provided, comprising: 1) an anode comprising particles of a tetrafluoroethylene polymer having a melt creep viscosity of poise and 2) a fluoropolymer binder containing a mixture of particles of a second polymer; 3) a cathode; 4) a separator between the cathode and the anode; and 5) an electrolyte in communication with the cathode, anode, and separator.

[0014] All of these embodiments are intended to be within the scope of the invention disclosed herein. These and other embodiments of the invention will become readily apparent to those skilled in the art from the following detailed description of the preferred embodiments, taken in conjunction with the accompanying drawings. The invention is not limited to any particular preferred embodiment disclosed.

[0015] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Methods and materials for use in the present invention are described herein; other suitable methods and materials known in the art may also be used. The materials, methods, and examples are illustrative only and are not intended to be limiting. All publications, patent applications, patents, sequences, database entries, and other references mentioned herein are incorporated herein by reference in their entirety. In case of conflict, the present specification, including definitions, will control. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a plot of particle size (D-50 in microns) versus pressure (psi) obtained using a particle size analyzer to determine the agglomerate disintegration of the dry, disintegrable fluoropolymer composition and a comparative composition. [Figure 2] 1 is a plot of particle size (D-50 in microns) versus pressure (psi) obtained using a particle size analyzer to determine the agglomerate disintegration of the dry, disintegrable fluoropolymer composition and a comparative composition. [Figure 3] 1 is a plot of particle size (D-50 in microns) versus pressure (psi) obtained using a particle size analyzer to determine the agglomerate disintegration of the dry, disintegrable fluoropolymer composition and a comparative composition. [Figure 4] 1 is a plot of particle size (D-50 in microns) versus pressure (psi) obtained using a particle size analyzer to determine the agglomerate disintegration of the dry, disintegrable fluoropolymer composition and a comparative composition. [Figure 5] 1 is a plot of particle size (D-50 in microns) versus pressure (psi) obtained using a particle size analyzer to determine the agglomerate disintegration of the dry, disintegrable fluoropolymer composition and a comparative composition. [Figure 6]1 is a plot of particle size (D-50 in microns) versus pressure (psi) obtained using a particle size analyzer to determine the agglomerate disintegration of the dry, disintegrable fluoropolymer composition and a comparative composition. [Figure 7] FIG. 1 is a plot of the cycling performance (discharge specific capacity (mAh / g) versus cycle number) at various C-rates of half-cell batteries using cathodes prepared by the dry process of the present invention compared to similar comparative half-cell batteries. [Figure 8] FIG. 1 is a plot of the cycling performance (discharge specific capacity (mAh / g) versus cycle number) at various C-rates of half-cell batteries using cathodes prepared by the dry process of the present invention compared to similar comparative half-cell batteries. [Figure 9] FIG. 1 is a plot of the cycling performance (discharge specific capacity (mAh / g) versus cycle number) at various C-rates of half-cell batteries using cathodes prepared by the dry process of the present invention compared to similar comparative half-cell batteries. [Figure 10] 1 is a plot of cyclic voltammetry measurements (current (mA) vs. potential vs. Li (V)) performed on anodes prepared using the present dry, disintegratable fluoropolymer composition and a comparative composition. [Figure 11] 1 is a plot of cyclic voltammetry measurements (current (mA) vs. potential vs. Li (V)) performed on anodes prepared using the present dry, disintegratable fluoropolymer composition and a comparative composition. [Figure 12] 1 is an interval plot showing the first coulombic efficiency (%) for half-cell batteries using anodes prepared by the dry process of the present invention prepared using the dry, crushable fluoropolymer composition of the present invention and comparative compositions. [Figure 13] 1 is a plot of the cycling performance (lithium desorption capacity (mAh / g)) versus cycle number at various C-rates of a half-cell battery using an anode prepared by a dry process of the present invention compared to a similar comparative half-cell battery. [Figure 14] 1A-1C are plan view images of the surface of an anode prepared by the dry method of the present invention by SEM at various magnifications. [Figure 15]1A-1C are plan view images of the surface of an anode prepared by the dry method of the present invention by SEM at various magnifications. [Figure 16] 1A-1C are plan view images of the surface of an anode prepared by the dry method of the present invention by SEM at various magnifications. [Figure 17] 1A-1C are plan view images of the surface of an anode prepared by the dry method of the present invention by SEM at various magnifications. DETAILED DESCRIPTION OF THE INVENTION

[0017] Binder Composition The present invention provides: i.) at least about 0.5×10 11 The present invention includes a fluoropolymer composition for use as a binder in a lithium ion secondary battery electrode, the fluoropolymer composition comprising: ii.) a dried, friable agglomerate of a first polymer comprising a tetrafluoroethylene polymer having a melt creep viscosity in poise; and ii.) a second polymer different from the first polymer.

[0018] In one embodiment, the agglomerate comprises particles of a first polymer and particles of a second polymer, hi another embodiment, the agglomerate comprises particles of a first polymer having at least a partial coating comprising a second polymer.

[0019] First Polymer—Tetrafluoroethylene Polymer The fluoropolymer composition includes a first polymer comprising a tetrafluoroethylene polymer. The tetrafluoroethylene polymer is a polymer having repeating units derived from tetrafluoroethylene monomers, also known as TFE (tetrafluoroethylene). The tetrafluoroethylene polymer has a high melt viscosity such that the polymer does not flow in the molten state and is not melt-processable. In one embodiment, the tetrafluoroethylene polymer is a tetrafluoroethylene homopolymer consisting of repeating units of tetrafluoroethylene monomers, commonly known in the art as polytetrafluoroethylene and commonly abbreviated as PTFE. In one embodiment, the tetrafluoroethylene polymer is a tetrafluoroethylene homopolymer consisting essentially of repeating units derived from tetrafluoroethylene monomers. In another embodiment, the tetrafluoroethylene polymer is a "modified" PTFE, which refers to a copolymer of tetrafluoroethylene and a low concentration of a comonomer such that the molecular weight of the resulting polymer is not substantially reduced below that of the homopolymer PTFE. The concentration of such a comonomer in the modified PTFE is less than 1% by weight, preferably less than 0.5% by weight. Generally, a minimum amount of at least about 0.05% by weight is used to have a significant effect. Exemplary comonomers in the modified PTFE include perfluoroolefins, particularly hexafluoropropylene (HFP) or perfluoro(alkyl vinyl ether) (PAVE), where the alkyl group contains 1 to 5 carbon atoms, perfluoro(ethyl vinyl ether) (PEVE), and perfluoro(propyl vinyl ether) (PPVE) are preferred, as well as chlorotrifluoroethylene (CTFE), perfluorobutyl ethylene (PFBE), or other similar monomers that introduce relatively sterically bulky side groups into the PTFE polymer chain.

[0020] The tetrafluoroethylene polymer has a molecular weight of about 0.5×10 11 Poise ~ approx. 6.0 x 10 11 In another embodiment, the tetrafluoroethylene polymer has a melt creep viscosity in the range of at least about 1.0×10 poise. 11 In another embodiment, the tetrafluoroethylene polymer has a melt creep viscosity of at least about 1.5×10 poise. 11 In another embodiment, the tetrafluoroethylene polymer has a melt creep viscosity of at least about 2.0 x 10 poise. 11 In another embodiment, the tetrafluoroethylene polymer has a melt creep viscosity of at least about 2.5×10 poise. 11 In another embodiment, the tetrafluoroethylene polymer has a melt creep viscosity of at least about 3.0×10 poise. 11 In another embodiment, the tetrafluoroethylene polymer has a melt creep viscosity of at least about 3.5×10 poise. 11 In another embodiment, the tetrafluoroethylene polymer has a melt creep viscosity of at least about 4.0 x 10 poise. 11 In another embodiment, the tetrafluoroethylene polymer has a melt creep viscosity of at least about 4.5×10 poise. 11 In another embodiment, the tetrafluoroethylene polymer has a melt creep viscosity of at least about 5.0 x 10 poise. 11 In another embodiment, the tetrafluoroethylene polymer has a melt creep viscosity of at least about 5.5×10 poise. 11 In another embodiment, the tetrafluoroethylene polymer has a melt creep viscosity of at least about 6.0 x 10 poise. 11The melt creep viscosity (MCV) is measured by the method described in Ebnesajjad, Sina, (2015), Fluoroplastics, Volume 1—Non-Melt Processible Fluoropolymers—The Definitive User's Guide and Data Book (2nd Edition), Appendix 5, Melt Creep Viscosity of Polytetrafluoroethylene, pp. 660-661, with reference to U.S. Pat. No. 3,819,594.

[0021] The present tetrafluoroethylene polymer is fibrillizable, meaning that the tetrafluoroethylene polymer is capable of forming nanosized (at least one dimension (i.e., <100 nm width)) fibrils that can vary in length from submicrometers to several micrometers to tens of micrometers when the tetrafluoroethylene polymer is subjected to shear forces, for example, during the present method.

[0022] Second Polymer The fluoropolymer composition includes a second polymer different from the first tetrafluoroethylene polymer, which can form an aqueous dispersion of fine particles of substantially the same size as the aqueous tetrafluoroethylene polymer dispersion or has solubility in the aqueous phase of the aqueous tetrafluoroethylene polymer dispersion, and which can contact the tetrafluoroethylene polymer primary particles and affect their coagulation during their coagulation to form aggregates.

[0023] In one embodiment, the second polymer is selected from the group consisting of fluoropolymers, polyolefins, polyesters, polyamides, polyimides, polyaramids, polyacrylates, polyurethanes, polyethers, polyol ethers, polyacrylonitriles, polyphosphazenes, polysiloxanes, polysulfides, and polysulfones, not including the first polymer (tetrafluoroethylene polymer).

[0024] In one embodiment, the second polymer is about 0.5×10 11 Poise ~ approx. 6.0 x 10 11 The first polymer has a melt creep viscosity in the poise range and is a tetrafluoroethylene polymer different from the first polymer, and is selected from the group consisting of tetrafluoroethylene polymer, tetrafluoroethylene perfluoro(alkyl vinyl ether) copolymer (PFA), fluorinated ethylene propylene copolymer (FEP), fluoroelastomer (FKM), ethylene tetrafluoroethylene copolymer (ETFE), polyvinylidene fluoride polymer (PVDF), polychlorotrifluoroethylene polymer (CTFE), and polyvinyl fluoride (PVF) polymer.

[0025] In one embodiment, the second polymer is about 0.5×10 11 Poise ~ approx. 6.0 x 10 11 In one embodiment, the first polymer comprises a tetrafluoroethylene polymer having a melt creep viscosity in the range of 10 poise and different from that of the first polymer comprising the tetrafluoroethylene polymer. In one embodiment, the first polymer comprises a tetrafluoroethylene polymer having a melt creep viscosity in the range of 10 poise and different from that of the first polymer comprising the tetrafluoroethylene polymer. 11a tetrafluoroethylene homopolymer consisting of repeating units of tetrafluoroethylene monomer, having a melt creep viscosity of poise, wherein the second polymer comprising the tetrafluoroethylene polymer has a concentration of comonomer repeating units of less than 1 wt. % and is at least about 0.5 x 10 11 It is a modified PTFE with a melt creep viscosity of poise.

[0026] In a preferred embodiment, the second polymer is a tetrafluoroethylene perfluoro(alkyl vinyl ether) (PFA) copolymer. PFA is a copolymer of tetrafluoroethylene (TFE) and perfluoro(alkyl vinyl ether) (PAVE) monomers, where the linear or branched perfluoroalkyl group of the PAVE monomer contains 1 to 5 carbon atoms. Preferred PAVE monomers have perfluoroalkyl groups containing 1, 2, 3, or 4 carbon atoms, and are known as perfluoro(methyl vinyl ether) (PMVE), perfluoro(ethyl vinyl ether) (PEVE), perfluoro(propyl vinyl ether) (PPVE), and perfluoro(butyl vinyl ether) (PBVE), respectively. PFA copolymers can be produced using several PAVE monomers, such as TFE / perfluoro(methyl vinyl ether) / perfluoro(propyl vinyl ether) copolymers, sometimes referred to in the art as MFA. PFA can contain about 1-15 wt% PAVE, but when a single PAVE monomer is used to form the PFA and TFE forms the remainder of the copolymer, a PAVE content of 2-8 wt%, preferably 3-5 wt%, is the most common PAVE content. In one embodiment, the MFA includes PMVE, with a composition of about 0.5-13 wt% PMVE and about 0.5-3 wt% PPVE, with the remainder being TFE, based on a total of 100 wt%. Preferably, the identity and amount of PAVE present in the PFA is such that the melting temperature of the PFA exceeds about 300°C. PFA is a fluoroplastic, not a fluoroelastomer. As a fluoroplastic, PFA is semi-crystalline, i.e., partially crystalline.

[0027] In one embodiment, the PFA is melt-processable and melt-formable, i.e., the PFA is sufficiently fluid in the molten state to be processed by melt processing, such as extrusion, to produce products with sufficient strength to be commercially useful. In one embodiment, this sufficient strength can be characterized by the PFA exhibiting an MIT flex life of at least 1000 cycles, preferably at least 2000 cycles, as measured on an 8 mil (0.21 mm) thick film. In the MIT flex life test, the film is gripped between jaws and bent back and forth over a range of 135°. In this embodiment, the strength of the PFA is demonstrated by the PFA's lack of brittleness. In one embodiment, the PFA has a melt flow rate (MFR) of preferably at least 0.1 g / 10 min, preferably at least 5 g / 10 min, and even more preferably at least 7 g / 10 min, measured at 372°C using a 5 kg weight on molten PFA according to ASTM D-1238 and ASTM D 3307-93.

[0028] In one embodiment, the PFA has a stable -CF3 end group as the predominant end group, with 10 as the most common end group resulting from the aqueous dispersion polymerization process used to make the PFA. 6 The PFA is fluorinated to have less than 50, preferably less than 25, total thermally unstable end groups, such as -CONH, -COF, -CHOH, and -COOH, per carbon atom. Processes for fluorination are known in the art, for example, in U.S. Pat. Nos. 4,743,658 and 6,838,545. According to one embodiment of the present invention, the PFA is not fluorinated, thereby providing a 10 6 At least about 200 of the end groups per carbon atom are the unstable end groups described above which result from the aqueous dispersion polymerization to form the PFA.

[0029] In an alternative embodiment, the second polymer is a perfluorinated ethylene-propylene (FEP) copolymer, a copolymer of tetrafluoroethylene and hexafluoropropylene (HFP). In one embodiment, the HFP content is about 5 to about 17 weight percent in FEP. In another embodiment, the FEP fluoropolymer comprises a TFE / HFP / PAVE terpolymer, with an HFP content of about 5 to about 17 weight percent, a PAVE content, preferably PEVE, of about 0.2 to about 4 weight percent, and the remainder being TFE, based on a total of 100 weight percent of the fluoropolymer. In one embodiment, the FEP fluoropolymer can be subjected to fluorination to reduce the number of thermally unstable end groups (e.g., carboxylic acid end groups). Fluorination can be carried out by known methods under a variety of conditions and with a variety of fluorine radical-generating compounds known in the art, as discussed previously herein with respect to PFA.

[0030] In an alternative preferred embodiment, the second polymer is a fluoroelastomer, including those known as FKMs (fluoroelastomers) and FFKMs (perfluoroelastomers).

[0031] In one embodiment, the second polymer is selected from the group consisting of fluoroelastomers: vinylidene fluoride / hexafluoropropylene copolymer (VDF / HFP), vinylidene fluoride / hexafluoropropylene / tetrafluoroethylene copolymer (VDF / HFP / TFE), vinylidene fluoride / perfluoro(methyl vinyl ether) / tetrafluoroethylene copolymer (VDF / PMVE / TFE), tetrafluoroethylene / perfluoro(methyl vinyl ether) copolymer (TFE / PMVE), tetrafluoroethylene / propylene copolymer (TFE / P), and ethylene / tetrafluoroethylene / perfluoro(methyl vinyl ether) copolymers (E / TFE / PMVE, E / TFE / PMVE).

[0032] In one embodiment, the fluoroelastomers useful in the present invention can be described as follows: (A) A vinylidene fluoride (VDF)-based fluoroelastomer, wherein VDF is (i) C2 to C8 perfluoroolefins such as tetrafluoroethylene (TFE) and hexafluoropropylene (HFP); (ii) vinyl fluoride (VF), trifluoroethylene, hexafluoroisobutene, formula CH2=CH-R f (In the formula, R f (iii) hydrogen-containing C2-C8 olefins such as perfluoroalkylethylenes in which the group (C1-C6) is a C1-C6 perfluoroalkyl group; (iv) C2-C8 fluoroolefins containing at least one of iodine, chlorine, and bromine, such as chlorotrifluoroethylene (CTFE); (iv) Formula CF2=CFOR f (per)fluoroalkyl vinyl ethers (PAVEs) (wherein R frepresents a C1-C6 (per)fluoroalkyl group, preferably -CF3, -C2F5, -C3F7), (v) Formula CF₂=CF₂OX (wherein X is a C₁-C₁ group containing a catenary oxygen atom) 12 (per)fluoro-oxy-alkyl vinyl ethers ((per)fluoro)-oxyalkyl, for example, perfluoro-2-propoxypropyl groups); (vi) (per)fluorodioxole; (vii) Formula: CF2 = CFOCF2OR f2 (Per)fluoro-methox-vinyl ethers having the formula f2 is selected from the group consisting of C1-C6 (per)fluoroalkyl, C5-C6 cyclic (per)fluoroalkyl, and C2-C6 (per)fluoroalkyl containing at least one catenary oxygen atom; R f2 is preferably -CF2CF3, -CF2CF2OCF3, or -CF3), (viii) fluoroelastomers based on vinylidene fluoride (VDF), copolymerized with at least one additional comonomer selected from the group consisting of C2-C8 non-fluorinated olefins, such as ethylene and propylene; and (B) A TFE-based fluoroelastomer, wherein the TFE is copolymerized with at least one additional comonomer selected from the group consisting of (i) to (viii) described immediately above.

[0033] In a preferred embodiment, the fluoroelastomer is a vinylidene fluoride copolymer, more preferably a copolymer of vinylidene fluoride, hexafluoropropylene, and tetrafluoroethylene.

[0034] In an alternative embodiment, the fluoroelastomer binder is crosslinked. Crosslinking not only improves the mechanical properties of the polymer, but also helps to provide good contact between the components of the electrode composition.

[0035] In some embodiments of the present fluoropolymer composition for use as a binder in a lithium-ion secondary battery electrode, the weight ratio of the tetrafluoroethylene polymer to the second polymer is from about 99:1 to about 25:75. In other embodiments, the ratio is from about 99:1 to about 50:50, or from about 99:1 to about 80:20, or from about 99:1 to about 90:10, or from about 99:1 to about 95:5, or from about 98:2 to about 92:8, or about 90:10, or about 95:5.

[0036] In a preferred embodiment, the second polymer is a tetrafluoroethylene perfluoro(alkyl vinyl ether) (PFA) polymer, and the weight ratio of tetrafluoroethylene polymer to tetrafluoroethylene perfluoro(alkyl vinyl ether) polymer is from about 99:1 to about 50:50, preferably from about 99:1 to about 90:10, or from about 98:2 to about 92:8, or about 95:5.

[0037] In a preferred embodiment, the second polymer is a fluoroelastomer (FKM), and the weight ratio of the tetrafluoroethylene polymer to the fluoroelastomer is about 99:1 to about 80:20, preferably about 99:1 to about 90:10, or about 95:5. The inventors have discovered that binders comprising co-coagulated compositions of the present tetrafluoroethylene polymer and the present fluoroelastomer containing more than 20 weight percent of the fluoroelastomer result in compositions that are rubbery and generally not fibrillizable, and therefore are undesirable for use as binders in lithium-ion secondary battery electrodes made by the present dry manufacturing process. Furthermore, the inventors have discovered that more than about 12 weight percent fluoroelastomer is generally the upper limit for producing a free-flowing, dry, disintegrable agglomerate powder, which is a desirable characteristic from the standpoint of a commercially viable electrode manufacturing process.

[0038] Method for producing electrode compositions - co-coagulation and crushing The present invention provides a method for producing an electrode composition for use in a lithium ion secondary battery electrode, comprising: I.) Co-coagulating, I.-i) at least about 0.5 × 10 11 an aqueous dispersion of a first polymer comprising a non-fibrillating tetrafluoroethylene polymer having a melt creep viscosity of poise; I.-ii) a second polymer different from the first polymer; and to produce disintegratable agglomerates of the first polymer and the second polymer; II.) Separating the disintegrable agglomerates formed in I.) from the aqueous phase; III.) Drying the disintegrable agglomerates separated in II.), and thereby forming dry, disintegrable agglomerates comprising particles of the first polymer and the second polymer.

[0039] The present invention further includes a method for producing an electrode composition for use in a lithium ion secondary battery electrode, comprising the step of IV.) grinding electrode active particles with the present dried, friable agglomerates comprising particles of a first polymer and a second polymer to form an electrode composition.

[0040] The present invention provides a method for producing an electrode composition for use in a lithium ion secondary battery electrode, comprising the steps I.) to III.) described above, IV.) grinding the dried electrode active particles with the dried, friable agglomerates formed in III.) to form the electrode composition.

[0041] The method includes the step of co-coagulating I.-i) an aqueous dispersion of particles of a first polymer comprising a non-fibrillating tetrafluoroethylene polymer and I.-ii) a second polymer different from the first polymer to produce disintegratable agglomerates composed of the first polymer and the second polymer.

[0042] Methods for coagulating aqueous dispersions of tetrafluoroethylene polymer primary particles to form aggregates are known in the art, for example, in U.S. Pat. No. 7,947,775 (B1). Such conventional methods for coagulating aqueous dispersions of tetrafluoroethylene polymer primary particles can be utilized in the co-coagulation step of the present method. In this method, an aqueous dispersion of a first polymer containing non-fibrillated tetrafluoroethylene polymer primary particles is coagulated in the presence of a second polymer different from the first polymer. In one embodiment of this co-coagulation, the second polymer is in the form of an aqueous dispersion that can be coagulated, and the aqueous dispersions of the first polymer and the second polymer are combined and mixed, and then this mixture of aqueous dispersions of the first polymer and the second polymer is co-coagulated.

[0043] In one embodiment, I.) co-coagulation is carried out using an aqueous dispersion of primary particles of a first polymer and an aqueous dispersion of particles of a second polymer, and the disintegratable agglomerates formed by this co-coagulation comprise particles of the first polymer and particles of the second polymer.

[0044] In another embodiment, I.) co-coagulation is carried out using an aqueous dispersion of primary particles of a first polymer and an aqueous solution of a second polymer, and the disintegratable agglomerates comprise particles of the first polymer having at least a partial coating comprising the second polymer.

[0045] In a further embodiment, I.) co-coagulation is carried out using an aqueous dispersion of primary particles of a first polymer and an aqueous dispersion of particles of a second polymer (SP1), and also an aqueous solution of a second polymer (SP2). In this embodiment, the second polymers SP1 and SP2 are the same or different. The disintegratable agglomerates formed by this co-coagulation comprise particles of the first polymer and SP1, and also particles of the first polymer having at least a partial coating comprising SP2.

[0046] Aqueous dispersions of tetrafluoroethylene polymers can be produced by known methods and are commercially available, for example, from Chemours FC LLC. Dispersion processes for polymerizing fluorinated monomers in aqueous media are known and established commercial technologies, as disclosed in, for example, U.S. Patent No. 6,429,258 (B1), PCT Patent Application Publication No. WO 2008 / 060461 (A1), and U.S. Patent Application Publication No. 2009 / 0281241 (A1), all of which are incorporated herein by reference. Aqueous dispersion processes for producing tetrafluoroethylene polymers use surfactants, also known as dispersants, to provide dispersion stability and allow fluoromonomer polymerization to proceed at commercially acceptable production rates to commercially acceptable solid concentrations.

[0047] Aqueous dispersion polymerization processes using surfactants for the production of tetrafluoroethylene polymers are known to yield primarily spherical primary particles (primary particles refer to as-polymerized particles) with raw dispersion particle sizes (RDPS) ranging from about 5 nm to about 250 nm, preferably from about 10 nm to about 200 nm, and more preferably from about 25 nm to about 150 nm. Rod-shaped dispersion particles (length-to-diameter, or L / D ratios greater than 3.0) can form when the molecular weight of the tetrafluoroethylene polymer is very high (not melt-processable) and the amount of modifying comonomer is low, if any, i.e., 0.3 mol % or less. While dispersion particles with L / D values ​​greater than 3.0 can form during the polymerization of high molecular weight tetrafluoroethylene polymers, the levels are generally low, about 10-15 wt %, and the L / D values ​​are low, less than 10, usually less than 5, unless the fluorosurfactant level is very high, generally higher than the surfactant critical micelle concentration value.

[0048] Aqueous dispersions of second polymer particles and / or solutions of second polymers for use in the methods of the present invention are commercially available or otherwise known in the art and can be purchased or prepared by known methods.

[0049] This co-coagulation can be achieved by combining and mixing a first polymer aqueous dispersion with a second polymer in the form of an aqueous dispersion or other suspended particulate form, followed by vigorous stirring (mechanical co-coagulation), optionally supplemented by the addition of electrolytes and / or water-immiscible solvents with low surface tension (chemical co-coagulation), or by known processes such as freeze-thaw procedures. This co-coagulation can also be achieved by diluting the raw aqueous dispersion to a polymer concentration of about 10 to about 20 weight percent, and optionally adjusting the pH to neutral or basic. A coagulation agent, such as a water-soluble organic compound or an inorganic salt or acid, can be added to the dispersion. Coagulation is facilitated by adding water-soluble organics (e.g., methanol, acetone), inorganic salts (e.g., potassium nitrate, ammonium carbonate), or inorganic salts (e.g., hydrochloric acid, sulfuric acid, nitric acid) as coagulants. The diluted dispersion is then vigorously stirred and / or agitated to cause the co-coagulation of the first polymer and the second polymer.

[0050] In a preferred embodiment, the co-coagulation method is carried out by chemical co-coagulation, for example using an ammonium carbonate solution, in combination with mechanical agitation. The inventors have surprisingly discovered that the results of such a process (as reported in this example) show that the use of chemical co-coagulation results in smaller and more disintegrable agglomerates compared to mechanical co-coagulation alone.

[0051] The primary (as-polymerized) tetrafluoroethylene copolymer particles formed in the aqueous dispersion polymerization process typically have a raw dispersion particle size (RDPS) in the range of about 5 nm to about 250 nm. Co-coagulation of the tetrafluoroethylene copolymer with the second polymer results in the formation of friable agglomerates having an average particle size of about 200 to about 1000 micrometers, preferably about 200 to about 500 micrometers.

[0052] In a preferred embodiment, the aggregates resulting from this I.) co-coagulation process are composed of i.) tetrafluoroethylene polymer primary particles and tetrafluoroethylene perfluoro(alkyl vinyl ether) polymer primary particles, or ii.) tetrafluoroethylene polymer primary particles and fluoroelastomer primary particles. In an alternative embodiment, the aggregates resulting from this I.) co-coagulation process consist essentially of i.) tetrafluoroethylene polymer primary particles and tetrafluoroethylene perfluoro(alkyl vinyl ether) polymer primary particles, or ii.) tetrafluoroethylene polymer primary particles and fluoroelastomer primary particles. In an alternative embodiment, the aggregates resulting from this I.) co-coagulation process consist of i.) tetrafluoroethylene polymer primary particles and tetrafluoroethylene perfluoro(alkyl vinyl ether) polymer primary particles, or ii.) tetrafluoroethylene polymer primary particles and fluoroelastomer primary particles.

[0053] The method includes the step of II.) separating the disintegrable agglomerates (formed in I.) from the aqueous phase. The agglomerates formed in the co-coagulation step can be separated from the aqueous phase by conventional techniques such as skimming or filtration.

[0054] The method includes III.) drying the disintegrable agglomerates (formed in II.) separation step). Drying the agglomerates can be performed by vacuum, high frequency, or heated air, so as not to over-fluidize the wet powder. Excessive friction or contact between particles, especially at elevated temperatures, can adversely affect the agglomerates due to possible fibrillation and the resulting loss of particulate structure, leading to potentially poorer properties in electrode compositions and films made from the agglomerates. Useful drying temperatures typically range from about 100 to about 180°C.

[0055] In one embodiment, the dried, disintegrable agglomerates are protected from fibrillation after drying. The tetrafluoroethylene polymers do not fibrillate below their beta transition point (about 19°C for tetrafluoroethylene homopolymer) during normal handling and shipping. In one embodiment, the agglomerates are stored and handled at temperatures below the transition point.

[0056] The agglomerates formed by steps I-III of the present process are referred to herein as "disintegrable" agglomerates. As used herein, the term disintegrable or disintegrability is defined by the ability of the agglomerates to be deagglomerated and broken down by the application of shear forces to more closely match the particle size of conventional solid-state electrode active materials, without substantially fibrillating the tetrafluoroethylene polymer, and to be homogeneously blended and mixed with the solid-state electrode active material. The inventors believe that more closely matching the particle size of the present disintegrable agglomerates and the particles derived therefrom to conventional solid-state electrode active materials results in a more homogeneously blended and mixed electrode binder composition, which in turn enables the production of higher-loaded electrode structures with reversible capacity retention. This surprising and beneficial result has been observed and is reported in the present experimental results.

[0057] In one embodiment, the shear force applied to the agglomerates results in deagglomeration and crushing of the agglomerates to form secondary or sub-agglomerates having an average particle size of from about 10 to about 300 micrometers, and the tetrafluoroethylene polymer is substantially non-fibrillated. In another embodiment, the shear force applied to the agglomerates results in deagglomeration and crushing of the agglomerates to form secondary or sub-agglomerates having an average particle size of from about 10 to about 60 micrometers, and the tetrafluoroethylene polymer is substantially non-fibrillated.

[0058] The method includes the step of IV.) grinding the electrode active particles with the dried, friable agglomerates (III.) formed in the drying step) to form the electrode composition.

[0059] The milling step IV.) of the process is carried out sufficiently to deagglomerate and break down the tetrafluoroethylene and second / other polymer agglomerates, resulting in the formation of smaller secondary agglomerates. In one embodiment, the secondary agglomerates have an average particle size of from about 10 to about 300 micrometers. In another embodiment, the secondary agglomerates have an average particle size of from about 10 to about 60 micrometers.

[0060] The milling step IV.) of the method is carried out sufficiently to deagglomerate and break down the agglomerates into sub-agglomerates having particle sizes substantially similar to those of the electrode active particles, and to homogeneously mix the electrode particles and the sub-agglomerates.

[0061] In this method, the tetrafluoroethylene polymer is substantially non-fibrillated during the I.) co-coagulation, II.) separation, and III.) drying steps, and is substantially fibrillated during the IV.) grinding step in the presence of, and in intimate contact with, the electrode active particles.

[0062] The comminution step of the method of the present invention can be carried out by known methods for comminuting fine powders and applying mixing and high shear forces. For example, techniques and machines envisioned for potential use to provide high shear forces to accomplish this step of IV.) comminution include jet milling, pin milling, impact grinding, and hammer milling, as well as similar techniques and devices. In one embodiment, jet milling is preferred, as generally taught in U.S. Pat. No. 7,342,770 B2, incorporated herein by reference.

[0063] In one embodiment, the method further comprises, between steps III.) drying and IV.) grinding, a step of pre-grinding the dried, friable agglomerates obtained after step III.) sufficient to deagglomerate and grind the dried, friable agglomerates without substantially fibrillating the tetrafluoroethylene polymer. In one embodiment, pre-grinding results in the formation of secondary agglomerates having an average particle size of from about 10 to about 300 micrometers. In another embodiment, pre-grinding results in the formation of secondary agglomerates having an average particle size of from about 10 to about 60 micrometers. These secondary agglomerates are then used in the grinding step IV.) of the method.

[0064] In all embodiments of the present method, milling step IV.) is carried out substantially dry and solvent-free, e.g., free of water and organic solvents such as N-methyl-2-pyrrolidone "NMP," commonly used as a carrier in battery binder manufacturing processes.

[0065] Lithium-ion secondary battery electrode film composition The present invention provides a composition for use in a lithium-ion secondary battery cathode film, comprising: i.) cathode active particles comprising a lithium transition metal oxide; ii.) conductive carbon; and iii.) at least about 0.5×10 11 The present invention includes a composition comprising a fluoropolymer binder containing a mixture of particles of a tetrafluoroethylene polymer having a melt creep viscosity of poise and particles of a second polymer different from the first polymer, wherein the tetrafluoroethylene polymer is fibrillated.

[0066] The present invention provides a composition for use in a lithium-ion secondary battery cathode film, comprising: i.) cathode active particles comprising a lithium transition metal oxide; ii.) conductive carbon; and iii.) at least about 0.5×10 11The composition further includes a fluoropolymer binder containing a mixture of particles of a tetrafluoroethylene polymer having a melt creep viscosity of poise and particles of a tetrafluoroethylene perfluoro(alkyl vinyl ether) polymer, wherein the tetrafluoroethylene polymer is fibrillated.

[0067] The present invention provides a composition for use in a lithium-ion secondary battery cathode film, comprising: i.) cathode active particles comprising a lithium transition metal oxide; ii.) conductive carbon; and iii.) at least about 0.5×10 11 and a fluoropolymer binder comprising a mixture of particles of a tetrafluoroethylene polymer having a melt creep viscosity of 100 poise and particles of a fluoroelastomer (FKM), wherein the tetrafluoroethylene polymer is fibrillated.

[0068] In one embodiment, the cathode film composition contains about 1 to about 10 weight percent fluoropolymer binder, about 95 to about 98 weight percent cathode active particles, and about 1 to about 10 weight percent conductive carbon, based on the combined weight of the fluoropolymer binder, cathode active particles, and conductive carbon.

[0069] The cathode active particles are selected from electrochemical cathode active materials known in the art. Examples of cathode active particles include metal oxides, metal sulfides, or lithium metal oxides. In preferred embodiments, the cathode active particles comprise a lithium transition metal oxide. Examples of lithium metal oxides include lithium nickel manganese cobalt oxide (NMC), lithium manganese oxide (LMO), lithium iron phosphate (LiFePO), lithium cobalt oxide (LCO), lithium titanate (LTO), and / or lithium nickel cobalt aluminum oxide (NCA). In some embodiments, the cathode active material is selected from layered transition metal oxides (e.g., LiCoO (LCO), Li(NiMnCo)O (NMC), LiNi 0.8 Co 0.15 Al 0.05O2(NCA), etc.), spinel-type manganese oxide (LiMn2O4(LMO), LiMn 1.5 Ni 0.5 O4 (LMNO), or olivine (LiFePO4, LiNiO2, LiNi 1-x Co x O2, LiNi 0.85 Co 0.1 Al 0.05 O2, LiNi 0.33 Co 0.33 Mn 0.33 O2, LiMn2O4, and combinations thereof.

[0070] The conductive carbon useful in cathode embodiments is selected from conductive carbon materials known in the art, including carbon black, porous carbon, carbon nanotubes, carbon fibers, vapor-grown carbon fibers (VGCF), graphene sheets, acetylene black, and combinations thereof.

[0071] The present invention provides a method for manufacturing anode active materials comprising: i.) anode active particles; and ii.) at least about 0.5×10 11 A composition for use in a lithium ion secondary battery anode film includes a fluoropolymer binder containing a mixture of particles of a tetrafluoroethylene polymer having a melt creep viscosity of poise and a second polymer different from the first polymer, wherein the tetrafluoroethylene polymer is fibrillated.

[0072] The present invention provides a composition for use in a lithium ion secondary battery anode film, comprising: i.) anode active particles; and ii.) at least about 0.5×10 11 The composition further includes a fluoropolymer binder containing a mixture of particles of a tetrafluoroethylene polymer having a melt creep viscosity of poise and particles of a tetrafluoroethylene perfluoro(alkyl vinyl ether) polymer, wherein the tetrafluoroethylene polymer is fibrillated.

[0073] The present invention provides a composition for use in a lithium ion secondary battery anode film, comprising: i.) anode active particles; and ii.) at least about 0.5×10 11 and a fluoropolymer binder comprising a mixture of particles of a tetrafluoroethylene polymer having a melt creep viscosity of 100 poise and particles of a fluoroelastomer (FKM), wherein the tetrafluoroethylene polymer is fibrillated.

[0074] In one embodiment, the anode film composition contains from about 1 to about 10 weight percent fluoropolymer binder and from about 90 to about 99 weight percent anode active particles.

[0075] The anode active particles are selected from conventional materials known in the art, such as graphite, graphene, lithium titanate, and silicon or silicon-containing materials.

[0076] Lithium-ion secondary battery - cathode embodiment The present invention provides a lithium ion secondary battery, 1) A cathode comprising a cathode electrode layer affixed to a metal current collector, the cathode electrode layer comprising a cathode electrode composition, the cathode electrode composition comprising: a) cathode active particles comprising a lithium transition metal oxide; b) conductive carbon, and c) a fluoropolymer binder, i) at least about 0.5 × 10 11 particles of a tetrafluoroethylene polymer having a melt creep viscosity of poise; ii) a cathode comprising a fluoropolymer binder containing a mixture with particles of a second polymer; 2) an anode; 3) a separator between the cathode and the anode; 4) A lithium ion secondary battery comprising the cathode, the anode, and an electrolyte in communication with the separator.

[0077] The inventors have discovered that embodiments of the present battery cathodes have higher discharge specific capacity at a given C-rate greater than C / 2 than an identical battery in which the fluoropolymer binder does not contain the second polymer. In one embodiment, the battery has at least a 50% higher discharge specific capacity at a given C-rate greater than C / 2 than an identical battery in which the fluoropolymer binder does not contain the second polymer. In another embodiment, the battery has at least a 100% higher discharge specific capacity at a given C-rate greater than C / 2 than an identical battery in which the fluoropolymer binder does not contain the second polymer. In another embodiment, the battery has at least a 150% higher discharge specific capacity at a given C-rate greater than C / 2 than an identical battery in which the fluoropolymer binder does not contain the second polymer. In another embodiment, the battery has at least a 200% higher discharge specific capacity at a given C-rate greater than C / 2 than an identical battery in which the fluoropolymer binder does not contain the second polymer. In another embodiment, the battery has at least 250% higher discharge specific capacity at a given C-rate where the C-rate is at least C / 2 greater than an identical battery where the fluoropolymer binder does not contain the second polymer.

[0078] In one embodiment of the battery including the cathode of the present invention, the fluoropolymer binder is prepared by co-coagulation of an aqueous dispersion of a tetrafluoroethylene polymer with an aqueous dispersion of a second polymer. In an alternative embodiment of the battery including the cathode of the present invention, the fluoropolymer binder is prepared by I.) co-coagulating an aqueous dispersion of a tetrafluoroethylene polymer with an aqueous dispersion of a second polymer to produce disintegratable agglomerates of the tetrafluoroethylene polymer and the second polymer, II.) separating the agglomerates from the aqueous phase, and III.) drying the agglomerates. In one embodiment of the battery including the cathode of the present invention, the co-coagulation is chemical co-coagulation.

[0079] In one embodiment of a battery including a cathode of the invention, agglomerate deagglomerability is characterized by the ability of agglomerates to be deagglomerated and broken down by application of shear force without substantially fibrillating the tetrafluoroethylene polymer. In one embodiment, the shear force applied to the agglomerates results in deagglomeration and breakup of the agglomerates without substantially fibrillating the tetrafluoroethylene polymer to form secondary agglomerates having an average particle size of from about 10 to about 300 micrometers. In another embodiment, the shear force applied to the agglomerates results in deagglomeration and breakup of the agglomerates without substantially fibrillating the tetrafluoroethylene polymer to form secondary agglomerates having an average particle size of from about 10 to about 60 micrometers.

[0080] In one embodiment of a battery including a cathode of the invention, the second polymer is selected from the group consisting of fluoropolymers, polyolefins, polyesters, polyamides, polyimides, polyaramids, polyacrylates, polyurethanes, polyethers, polyol ethers, polyacrylonitriles, polyphosphazenes, polysiloxanes, polysulfides, and polysulfones, having a melt creep viscosity that differs from the melt creep viscosity of the first polymer.

[0081] In one embodiment of a battery including a cathode of the invention, the second polymer is selected from the group consisting of tetrafluoroethylene polymer, tetrafluoroethylene perfluoro(alkyl vinyl ether) (PFA), fluorinated ethylene propylene (FEP), fluoroelastomer (FKM), ethylene tetrafluoroethylene polymer (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (CTFE), and polyvinyl fluoride (PVF), having a melt creep viscosity different from that of the first polymer. In a preferred embodiment, the second polymer comprises particles of tetrafluoroethylene perfluoro(alkyl vinyl ether) polymer, particles of fluoroelastomer (FKM), or a combination thereof.

[0082] In one embodiment of a battery including the cathode of the present invention, the cathode electrode composition is prepared by milling a dry, disintegrable agglomerate comprising cathode active particles, conductive carbon, and a fluoropolymer binder, thereby fibrillating the tetrafluoroethylene polymer. In a preferred embodiment, the milling is carried out substantially free of solvent.

[0083] In one embodiment of a battery including a cathode of the present invention, the cathode electrode composition contains about 1 to about 10 weight percent fluoropolymer binder, about 95 to about 98 weight percent cathode active particles, and about 1 to about 10 weight percent conductive carbon, based on the total weight of the fluoropolymer binder, cathode active particles, and conductive carbon.

[0084] In one embodiment of a battery including a cathode of the invention, the weight ratio of the tetrafluoroethylene polymer to the second polymer is from about 99:1 to about 25:75. In other embodiments, the ratio is from about 99:1 to about 50:50, or from about 99:1 to about 80:20, or from about 99:1 to about 90:10, or from about 99:1 to about 95:5, or from about 98:2 to about 92:8, or about 90:10, or about 95:5. In a preferred embodiment, the second polymer is a tetrafluoroethylene perfluoro(alkyl vinyl ether) (PFA) polymer, and the weight ratio of the tetrafluoroethylene polymer to the tetrafluoroethylene perfluoro(alkyl vinyl ether) polymer is from about 99:1 to about 50:50, preferably from about 99:1 to about 90:10, or from about 98:2 to about 92:8, or about 95:5. In another preferred embodiment, the second polymer is a fluoroelastomer (FKM) and the weight ratio of tetrafluoroethylene polymer to fluoroelastomer is from about 99:1 to about 80:20, preferably from about 99:1 to about 90:10, or about 95:5.

[0085] In one embodiment of a battery including a cathode of the invention, the tetrafluoroethylene polymer is selected from the group consisting of A) a tetrafluoroethylene homopolymer consisting essentially of tetrafluoroethylene monomer repeat units, and B) a modified tetrafluoroethylene polymer consisting essentially of tetrafluoroethylene monomer repeat units and about 1 weight percent or less of a modifying perfluoro(alkyl vinyl ether) comonomer repeat unit, and the second polymer comprises a tetrafluoroethylene perfluoro(alkyl vinyl ether) polymer.

[0086] In one embodiment, the present invention provides a lithium ion secondary battery comprising a cathode of the present invention, 1) A cathode comprising a cathode electrode layer affixed to a metal current collector, the cathode electrode layer comprising a cathode electrode composition, the cathode electrode composition comprising: a) cathode active particles comprising a lithium transition metal oxide; b) conductive carbon, and c) a fluoropolymer binder, i) particles of tetrafluoroethylene perfluoro(alkyl vinyl ether) polymer; ii) a fluoropolymer binder containing a mixture of particles of a tetrafluoroethylene polymer, the tetrafluoroethylene polymer comprising: (1) (a) a tetrafluoroethylene homopolymer consisting essentially of tetrafluoroethylene monomer repeat units; (b) a modified tetrafluoroethylene polymer consisting essentially of tetrafluoroethylene monomer repeat units and about 1 weight percent or less of a modifying perfluoro(alkyl vinyl ether) comonomer (modifier) ​​repeat unit; (2) at least about 0.5 × 10 11 having a melt creep viscosity of poise; (3) a fibrillated cathode; 2) an anode; 3) a separator between the cathode and the anode; 4) A lithium ion secondary battery comprising the cathode, the anode, and an electrolyte in communication with the separator.

[0087] Lithium-ion secondary battery - anode embodiment The present invention provides a lithium ion secondary battery, 1) An anode comprising an anode electrode layer affixed to a metal current collector, the anode electrode layer comprising an anode electrode composition, the anode electrode composition comprising: a) anode active particles; b) a fluoropolymer binder, i) at least about 0.5 × 10 11 particles of a tetrafluoroethylene polymer having a melt creep viscosity of poise; ii) an anode comprising a fluoropolymer binder containing a mixture with particles of a second polymer; 2) a cathode; and 3) a separator between the cathode and the anode; 4) A lithium ion secondary battery comprising the cathode, the anode, and an electrolyte in communication with the separator.

[0088] The inventors have discovered that embodiments of the present battery anode have a higher lithium desorption capacity (mAh / g) at a given C-rate than an identical battery in which the fluoropolymer binder does not contain a second polymer. In one embodiment, the battery has a lithium desorption capacity (mAh / g) at a given C-rate that is at least 3% higher than an identical battery in which the fluoropolymer binder does not contain a second polymer. In another embodiment, the battery has a lithium desorption capacity (mAh / g) at a given C-rate that is at least 5% higher than an identical battery in which the fluoropolymer binder does not contain a second polymer. In another embodiment, the battery has a lithium desorption capacity (mAh / g) at a given C-rate that is at least 7% higher than an identical battery in which the fluoropolymer binder does not contain a second polymer. In another embodiment, the battery has a lithium desorption capacity (mAh / g) at a given C-rate that is at least 10% higher than an identical battery in which the fluoropolymer binder does not contain a second polymer.

[0089] The inventors have found that in embodiments of the present battery anode, the anode exhibits an electrochemical reduction of 0.25 V to 0.9 V vs. Li / Li+, as measured by cyclic voltammetry, that is decreased relative to an anode in an identical battery where the fluoropolymer binder does not contain the second polymer. In one embodiment, the anode exhibits an electrochemical reduction of 0.25 V to 0.9 V vs. Li / Li+, as measured by cyclic voltammetry, that is decreased by at least about 30% relative to an anode in an identical battery where the fluoropolymer binder does not contain the second polymer. In another embodiment, the anode exhibits an electrochemical reduction of 0.25 V to 0.9 V vs. Li / Li+, as measured by cyclic voltammetry, that is decreased by at least about 40% relative to an anode in an identical battery where the fluoropolymer binder does not contain the second polymer. In another embodiment, the anode exhibits an electrochemical reduction of Li / Li+ by cyclic voltammetry measurement from 0.25 V to 0.9 V vs. Li / Li+ that is reduced by at least about 50% relative to an anode in an identical battery where the fluoropolymer binder does not contain the second polymer. In another embodiment, the anode exhibits an electrochemical reduction of Li / Li+ by cyclic voltammetry measurement from 0.25 V to 0.9 V vs. Li / Li+ that is reduced by at least about 60% relative to an anode in an identical battery where the fluoropolymer binder does not contain the second polymer.

[0090] In one embodiment of a battery including an anode of the present invention, the fluoropolymer binder is prepared by co-coagulation of an aqueous dispersion of a tetrafluoroethylene polymer with an aqueous dispersion of a second polymer. In an alternative embodiment, the fluoropolymer binder is prepared by I.) co-coagulating an aqueous dispersion of a tetrafluoroethylene polymer with an aqueous dispersion of a second polymer to produce disintegrable agglomerates of the tetrafluoroethylene polymer and the second polymer, II.) separating the agglomerates from the aqueous phase, and III.) drying the agglomerates. In a preferred embodiment, the co-coagulation is chemical co-coagulation.

[0091] In one embodiment of a battery including an anode of the invention, agglomerate breakability is characterized by the ability of the agglomerates to be deagglomerated and broken down by the application of shear force without substantially fibrillating the tetrafluoroethylene polymer. In one embodiment, the shear force applied to the agglomerates results in deagglomeration and breakup of the agglomerates without substantially fibrillating the tetrafluoroethylene polymer to form secondary agglomerates having an average particle size of from about 10 to about 300 micrometers. In another embodiment, the shear force applied to the agglomerates results in deagglomeration and breakup of the agglomerates without substantially fibrillating the tetrafluoroethylene polymer to form secondary agglomerates having an average particle size of from about 10 to about 60 micrometers.

[0092] In one embodiment of a battery including an anode of the invention, the second polymer is selected from the group consisting of fluoropolymers, polyolefins, polyesters, polyamides, polyimides, polyaramids, polyacrylates, polyurethanes, polyethers, polyol ethers, polyacrylonitriles, polyphosphazenes, polysiloxanes, polysulfides, and polysulfones, having a melt creep viscosity that differs from the melt creep viscosity of the first polymer.

[0093] In one embodiment of a battery including an anode of the invention, the second polymer is selected from the group consisting of tetrafluoroethylene polymer, tetrafluoroethylene perfluoro(alkyl vinyl ether) (PFA), fluorinated ethylene propylene (FEP), fluoroelastomer (FKM), ethylene tetrafluoroethylene polymer (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (CTFE), and polyvinyl fluoride (PVF), having a melt creep viscosity different from that of the first polymer. In a preferred embodiment, the second polymer comprises particles of tetrafluoroethylene perfluoro(alkyl vinyl ether) polymer, or particles of fluoroelastomer (FKM), or a combination thereof.

[0094] In one embodiment of a battery including the anode of the present invention, the anode electrode composition is prepared by milling anode active particles and dry, friable agglomerates comprising a fluoropolymer binder, thereby fibrillating the fluoropolymer binder. In a preferred embodiment, the milling is carried out substantially free of solvent.

[0095] In one embodiment of a battery including an anode of the invention, the anode electrode composition contains from about 1 to about 10 weight percent of a fluoropolymer binder and from about 90 to about 99 weight percent of anode active particles.

[0096] In one embodiment of a battery including an anode of the invention, the weight ratio of the tetrafluoroethylene polymer to the second polymer is from about 99:1 to about 25:75. In other embodiments, the ratio is from about 99:1 to about 50:50, or from about 99:1 to about 80:20, or from about 99:1 to about 90:10, or from about 99:1 to about 95:5, or from about 98:2 to about 92:8, or about 90:10, or about 95:5. In a preferred embodiment, the second polymer is a tetrafluoroethylene perfluoro(alkyl vinyl ether) (PFA) polymer, and the weight ratio of the tetrafluoroethylene polymer to the tetrafluoroethylene perfluoro(alkyl vinyl ether) polymer is from about 99:1 to about 50:50, preferably from about 99:1 to about 90:10, or from about 98:2 to about 92:8, or about 95:5. In another preferred embodiment, the second polymer is a fluoroelastomer (FKM) and the weight ratio of tetrafluoroethylene polymer to fluoroelastomer is from about 99:1 to about 80:20, preferably from about 99:1 to about 90:10, or about 95:5.

[0097] Lithium-ion secondary battery - cathode and anode embodiments In one embodiment, the present invention provides a lithium ion secondary battery comprising the cathode and anode of the present invention, 1) A cathode comprising a cathode electrode layer affixed to a metal current collector, the cathode electrode layer comprising a cathode electrode composition, the cathode electrode composition comprising: a. cathode active particles comprising a lithium transition metal oxide; b. conductive carbon, and c. a fluoropolymer binder, i. particles of tetrafluoroethylene perfluoro(alkyl vinyl ether) polymer; ii. A fluoropolymer binder comprising a mixture of particles of a tetrafluoroethylene polymer, the tetrafluoroethylene polymer comprising: 1. a. a tetrafluoroethylene homopolymer consisting essentially of tetrafluoroethylene monomer repeat units; b. modified tetrafluoroethylene polymers consisting essentially of tetrafluoroethylene monomer repeat units and about 1 weight percent or less of modifying perfluoro(alkyl vinyl ether) comonomer (modifier) ​​repeat units; 2. At least about 0.5 x 10 11 having a melt creep viscosity of poise; 3. A cathode that is fibrillated; 2) An anode comprising an anode electrode layer affixed to a metal current collector, the anode electrode layer comprising an anode electrode composition, the anode electrode composition comprising: a. anode active particles; b. a fluoropolymer binder, iii. particles of tetrafluoroethylene perfluoro(alkyl vinyl ether) polymer or particles of fluoroelastomer (FKM); iv. a fluoropolymer binder containing a mixture of particles of a tetrafluoroethylene polymer, wherein the tetrafluoroethylene polymer is 1. At least about 0.5 x 10 11 having a melt creep viscosity of poise; 2. An anode that is fibrillated; 3) a separator between the cathode and the anode; 4) A lithium ion secondary battery includes a cathode, an anode, and an electrolyte in communication with a separator.

[0098] electrolyte The electrolyte of the lithium-ion secondary battery includes a conventional electrolyte for lithium-ion secondary batteries that allows the battery to operate continuously without performance degradation. The electrolyte facilitates ionic communication between the electrodes of the battery and is typically in contact with the cathode, anode, and separator. In one embodiment, the battery uses a suitable lithium-containing electrolyte, such as a lithium salt and a solvent, such as a non-aqueous or organic solvent, or a fluorinated organic solvent. Generally, the lithium salt includes an anion that is redox stable. In some embodiments, the anion can be monovalent. In some embodiments, the lithium salt can be selected from hexafluorophosphate (LiPF), lithium tetrafluoroborate (LiBF), lithium perchlorate (LiClO), lithium bis(trifluoromethanesulfonyl)imide (LiN(SOCF)), lithium trifluoromethanesulfonate (LiSOCF), lithium bis(oxalato)borate (LiBOB), and combinations thereof. In some embodiments, the electrolyte can include a quaternary ammonium cation and an anion selected from the group consisting of hexafluorophosphate, tetrafluoroborate, and iodide. In some embodiments, the salt concentration can be about 0.1 mol / L (M) to about 5 M, about 0.2 M to about 3 M, or about 0.3 M to about 2 M. In further embodiments, the salt concentration of the electrolyte can be about 0.7 M to about 1 M. In certain embodiments, the salt concentration of the electrolyte can be about 0.2 M, about 0.3 M, about 0.4 M, about 0.5 M, about 0.6 M, about 0.7 M, about 0.8 M, about 0.9 M, about 1 M, about 1.1 M, about 1.2 M, or any range of values ​​therebetween.

[0099] In some embodiments of the present lithium-ion secondary battery, the electrolyte includes a liquid solvent. In further embodiments, the solvent can be an organic solvent. In some embodiments, the solvent can include one or more functional groups selected from carbonates, ethers, and / or esters. In some embodiments, the solvent can include carbonates. In further embodiments, the carbonate can be selected from cyclic carbonates such as, for example, ethylene carbonate (EC), propylene carbonate (PC), vinyl ethylene carbonate (VEC), vinylene carbonate (VC), fluoroethylene carbonate (FEC), methyl(2,2,2-trifluoroethyl)carbonate (FEMC), and combinations thereof, or acyclic carbonates such as, for example, dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), and combinations thereof. In some embodiments, the electrolyte can include LiPF and one or more carbonates. Exemplary organic solvent electrolytes include those known in the art as "Gen2" electrolytes, which are 1.0 M LiPF in ethylene carbonate (EC) and ethyl methyl carbonate (EMC), with a weight ratio of EC:EMC of 3:7. In one embodiment, the electrolyte for use in the present high-voltage lithium-ion secondary batteries is a fluorinated organic solvent electrolyte. For example, a fluorinated electrolyte designated FEC-FEMC is 1 M LiPF in fluoroethylene carbonate (FEC) and methyl (2,2,2-trifluoroethyl) carbonate (FEMC), with a volume ratio of FEC:FEMC of 1:9.

[0100] Separator The separator of the present lithium ion secondary battery includes a conventional separator for lithium ion secondary batteries that allows continuous operation of the battery without performance degradation. The separator is configured to electrically insulate two adjacent electrodes on either side of the separator while allowing ionic communication between the two adjacent electrodes. The separator can include a suitable porous, electrically insulating material. In some embodiments, the separator can include a polymer material. For example, the separator can include a cellulosic material (e.g., paper), a polyethylene resin, a polypropylene resin, and / or a mixture thereof. [Example]

[0101] The present invention will now be described in more detail by way of specific examples. The following examples are provided for illustrative purposes and are not intended to limit the present invention in any way. Those skilled in the art will readily recognize a variety of non-critical parameters that can be changed or modified to achieve essentially the same results.

[0102] material Comparative Example PFA1: A copolymer of tetrafluoroethylene TFE and perfluoro(propyl vinyl ether) (PPVE) having a PPVE content of 4 weight percent and a melt flow rate of 15 g / 10 min. 6 It has a total of approximately 200 carboxylic acid-type unstable ends per carbon atom. Manufactured by Chemours FC LLC.

[0103] Comparative Example FKM1: A copolymer of vinylidene fluoride (VDF) and hexafluoropropylene (HFP) having an HFP content of 40 weight percent and a Mooney viscosity of 114 MU measured at 121° C., manufactured by Chemours FC LLC.

[0104] Comparative Example FKM2: A copolymer of tetrafluoroethylene and perfluoro(methyl vinyl ether) PMVE, having a PMVE content of 45 weight percent and a Mooney viscosity of 84 MU measured at 121° C., manufactured by Chemours FC LLC.

[0105] Comparative Example FKM3: Viton® Type F copolymer of vinylidene fluoride (VDF), hexafluoropropylene (HFP), and tetrafluoroethylene (TFE), 36 wt% VDF, 70% F, −8° C. Tg. Manufactured by Chemours FC LLC.

[0106] Comparative Example FKM4: Viton® type GFLT copolymer of vinylidene fluoride (VDF), perfluoro(methyl vinyl ether) (PMVE), and tetrafluoroethylene (TFE), 36% VDF, 67% F, −23° C. Tg. Manufactured by Chemours FC LLC.

[0107] Comparative Example PTFE1: 4.0 x 10 manufactured by Chemours FC LLC 11 A tetrafluoroethylene homopolymer having a melt creep viscosity in poise.

[0108] Example PTFE1+5% PFA1: A co-coagulated composition containing 95% by weight of PTFE1 and 5% by weight of PFA1, produced by the present co-coagulation method.

[0109] Example PTFE1+10% PFA1: A co-coagulated composition containing 95% by weight of PTFE1 and 10% by weight of PFA1, produced by the present co-coagulation method.

[0110] Comparative Example PTFE2: 1.5 x 10 11 A modified tetrafluoroethylene polymer containing 0.018 wt% copolymerized PFBE (perfluorobutylethylene) and 0.016 wt% HFP (hexafluoropropylene) modifier, having a melt creep viscosity in poise.

[0111] Example PTFE2+5% PFA1: A co-coagulated composition containing 95% by weight of PTFE2 and 5% by weight of PFA1 produced by the present co-coagulation method.

[0112] Example PTFE2+10% PFA1: A co-coagulated composition containing 95% by weight of PTFE2 and 5% by weight of PFA1 produced by the present co-coagulation method.

[0113] Example PTFE2+5% FKM2: A co-coagulated composition containing 95% by weight of PTFE2 and 5% by weight of FKM2 produced by the present co-coagulation method.

[0114] Comparative Example PTFE3: 1.47 x 10 manufactured by Chemours FC LLC 10 A modified tetrafluoroethylene polymer containing 0.128 wt% copolymerized PPVE (perfluoro(propyl vinyl ether)) as a modifier, having a melt creep viscosity of poise.

[0115] Example PTFE3+5% PFA1: A co-coagulated composition containing 95% by weight of PTFE3 and 5% by weight of PFA1 produced by the present co-coagulation method.

[0116] Example PTFE3+10% PFA1: A co-coagulated composition containing 95% by weight of PTFE3 and 10% by weight of PFA1 produced by the present co-coagulation method.

[0117] Example PTFE3+5% FKM1: A co-coagulated product containing 95% by weight of PTFE3 and 5% by weight of FKM1 produced by the present co-coagulation method.

[0118] Comparative Example PTFE4: 9.16 x 10 manufactured by Chemours FC LLC 10 A modified tetrafluoroethylene polymer containing 0.038 wt% copolymerized PFBE (perfluorobutylethylene) as a modifier, having a melt creep viscosity of poise.

[0119] In this specification and the accompanying drawings, examples may be abbreviated as "Ex." and comparative examples may be abbreviated as "CEx."

[0120] Co-coagulation process for producing the present fluoropolymer composition The following is an example of the present co-coagulation method for making two present fluoropolymer compositions: The present fluoropolymer compositions described in this example were produced according to the co-coagulation method described herein.

[0121] Example PTFE2 + 5% PFA1 Preparation of a fluoropolymer composition. A 3-liter glass vessel equipped with four stainless steel baffles was charged with 823 mL of demineralized water, 946 mL of Comparative Example PTFE2 aqueous dispersion having a polymer solids content of 34.63%, 88 mL of Comparative Example PFA1 aqueous dispersion having a polymer solids content of 21.47%, and 43 mL of 20% ammonium carbonate solution. A mechanical stirrer equipped with two four-blade turbine agitators mounted on a central shaft completed the apparatus. The dimensions of the complete coagulator assembly were as follows: The 3-liter glass vessel had an internal diameter of 13 cm. The baffles were fitted with thin metal rings and were 13 cm high and 1.5 cm wide. The two agitators were spaced 6 cm apart on the shaft and consisted of four blades (the blades were 1.5 cm wide and 4.5 cm long) with a 45-degree pitch. The rotation was directional, creating an upward flow of fluid. With the lid in place (through which the agitator shaft extends), the contents of the coagulator were rocked at 800 rpm using a Caframo BDC3030 motor until the solid co-coagulated polymer was sufficiently separated from the water. After decanting, the wet powder was washed with 1000 mL of demineralized water and then filtered through cheesecloth. The powder was dried in a tray oven at a temperature of 150°C to yield the co-coagulated Example PTFE2 + 5% PFA1 fluoropolymer composition having a DSC first melting point of 341.5°C.

[0122] Example Preparation of PTFE3+5% FKM1 fluoropolymer composition. Example PTFE3+5%FKM1 fluoropolymer composition having a DSC first melting point of 338.48°C was prepared according to the procedure for the preparation of Example PTFE2+5%PFA1 provided earlier herein using 74 mL of deionized water, 1643 mL of Comparative Example PTFE3 aqueous dispersion having a polymer solids content of 34.63%, and 140 mL of Comparative Example FKM1 aqueous dispersion having a polymer solids content of 11.92%.

[0123] Test Method Polymer Solids - The polymer solids of the fluoropolymer dispersions were determined gravimetrically by evaporating a weighed mass of the dispersion to dryness using a Mettler Toledo HX204 moisture analyzer.

[0124] Melting Point - First melting points by differential scanning calorimetry were determined using a TA Instruments Q2000 instrument operated at a ramp rate of 2 degrees / minute and Universal Analysis 2000 software version 4.5A.

[0125] Test Method: Characterization of Solid Aerosol Particle Size Using a Variable Shear Air Jet The particle size and friability of the fluoropolymer composition powders were characterized under various levels of dispersion energy from a pressurized air jet using a Microtrac MRB S3500 particle size analyzer. This instrument measures particle size distribution by laser diffraction and provides a quantitative assessment of the friability of the fluoropolymer composition compared to pure tetrafluoroethylene polymer.

[0126] Key equipment operating settings for these experiments included a Dry Feeder TurboTrac, 95 PSI dry air, 0-60 PSI air (0-75 LPM) to the eductor, high shear eductor gap setting of 1, and 4-6 inches of H2O vacuum.

[0127]

number

[0128] The key calculation parameters for these experiments included particle refractive index: 1.35, particle shape: irregular, and particle transparency: transparent.

[0129] The experimental procedure using this instrument included the following: 1) storing the sample under refrigeration (4 °C) until ready for measurement, 2) setting the desired pressure on the instrument, 3) using a spatula, gently scoop 250 mg to 500 mg of the fluoropolymer composition onto weighing paper, then pour the sample onto a sampling tray, 4) loading the sampling tray into the "Turbotrac" and running the measurement via the device computer software.

[0130] Procedural notes for experiments using this instrument: 1) Depending on the pressure and flow rate used and sample behavior, 250 mg to 500 mg of fluoropolymer composition powder is measured. Too much fluoropolymer composition powder can clog the eductor system or produce erroneous results due to high particle concentration effects. Too little powder will not provide a sufficient detection signal and give insufficient results. 2) Powder can accumulate in the eductor, especially when measuring small particle size powders at high air flow rates. Powder buildup will stop the powder flow and require cleaning. 3) The air pressure supplied to the eductor is varied to adjust the level of dispersion energy / shear on the fluoropolymer composition particles. Higher pressure results in more particle breakage and produces smaller particle sizes. A volumetric flow meter was added to measure the air flow to the eductor. A pressure of 0 psi means that there is no pressurized air supplied to the eductor, so the powder flows with a vacuum suction. 4) For a pressure of 2.3 psi, a secondary air regulator was added in series with the eductor air supply.

[0131] Eductor air flow rate at a given pressure:

[0132] [Table 1]

[0133] The results are shown in the following table and in Figures 1 to 5.

[0134] [Table 2]

[0135] Discussion of test method results: Characterization of solid aerosol particle size using variable shear air jets As discussed previously herein, for polymerized tetrafluoroethylene polymers, primary particles typically have a submicron size range. These primary particles aggregate to form larger agglomerates or aggregates with sizes ranging from 400 to 600 microns. During this particle size analysis test, the agglomerated powder is subjected to various levels of energy via a pressurized air jet. Increasing energy levels lead to greater reductions in measured aggregate size, a quantitative assessment of the disintegration of fluoropolymer composition aggregates. As shown in Figure 1, all conventional tetrafluoroethylene polymer powders exhibit some reduction in aggregate size as energy levels increase. However, different tetrafluoroethylene polymer aggregate powders exhibit differences in the level of aggregate size reduction (disintegration), particularly at higher energy levels.

[0136] The inventors have surprisingly found that: i.) at least about 0.5×10 11 It has been discovered that for the present co-coagulated, dry, disintegrable agglomerates comprising ii.) a first polymer comprising a tetrafluoroethylene polymer having a melt creep viscosity in poise, and ii.) a second polymer different from the first polymer, particle size reduction without substantial fibrillation of the tetrafluoroethylene polymer is significantly reduced.

[0137] This effect can be seen from a review of the experimental data in the previous tables and Figures 2-5. These examples show that even at low energy levels (10 psi or less), the fluoropolymer composition aggregate size is substantially smaller when used with the co-coagulated product than when used with pure tetrafluoroethylene polymer powder to form the co-coagulated product.

[0138] For example, referring to Figure 4, at low energy levels, the base Comparative Example PTFE2 has an aggregate size of 548 microns. When Comparative Example PTFE2 is co-coagulated with another fluoropolymer (5 wt% Comparative Example PFA1), the aggregate size for the co-coagulated product Example PTFE2 + 5% PFA1 is reduced to 258 microns.

[0139] Comparison of chemical versus mechanical coagulation on agglomerate disintegration. The co-coagulation of Comparative Example PTFE3 with 5% Comparative Example PFA1 aqueous dispersion mixture was carried out by substantially the same procedure as that described above for the preparation of Example PTFE2 + 5% PFA1 fluoropolymer composition using ammonium carbonate solution combined with mechanical agitation (chemical co-coagulation). The same procedure was followed, except that no ammonium carbonate solution was added and the mixture was co-coagulated using only mechanical agitation (mechanical co-coagulation).

[0140] The resulting agglomerated powder was then subjected to various levels of energy from a pressurized air jet using the previously described "Test Method: Characterization of Solid Aerosol Particle Size Using a Variable Shear Air Jet." The results are shown in the table below and in Figure 6.

[0141] Chemical versus mechanical co-coagulation

[0142] [Table 3]

[0143] The results surprisingly show that the use of chemical co-coagulation results in smaller and more friable agglomerates compared to mechanical co-coagulation alone.

[0144] Cathode The fluoropolymer composition was used to prepare test cathodes according to the following procedure: Mixing: The cathode active material (lithiated transition metal oxide) and conductive carbon were mixed for 15 minutes using a mortar / pestle. The fluoropolymer binder of the present fluoropolymer composition was added and loosely mixed into the CAM / conductive carbon powder mixture. The three electrode components were then mixed with 110 mm ceramic beads / gram of electrode mixture in a 125 mL HDPE bottle using a roll mill at a speed of 90 revolutions / minute for 30 minutes. The total batch weight was 10 g.

[0145] Electrode (Cathode) Formation: The cathode electrode mixture (3 g) was placed on a hot plate heated to 100°C and manually spread using a steel roller heated to 100°C. Once the initial film was formed, the film was folded and re-stretched to increase the film's strength. This process was repeated until a 300 μm thick free-standing cathode film was produced. This free-standing cathode film was then placed inside a folded piece of 50 μm thick aluminum shim. The cathode film and shim were passed through vertically fed calender rolls to reduce the thickness. The roll gap distance was started at 350-450 μm and gradually decreased by 50 μm at a time to 200 μm, then to 180, 150, and finally to 130 μm. As the gap decreased below 200 μm, the number of gap passes increased. The film was calendered until it reached a thickness of 70-90 μm. The cathode was calendered at approximately 30 mg / cm. 2 It is a high load.

[0146] Sample composition: LiNi 0.6 Mn 0.2 Co 0.2A cathode containing O2 (NMC622), Super P, and the present fluoropolymer composition in a weight percent ratio of 90:5:5 was prepared. Half cells were cycled under the assumption that NMC622 had a practical capacity of 190 mAh / g.

[0147] Half-cell configuration: The cathode (15 mm) was self-cycling. Li metal was used as the anode (15.6 mm). A Celgard separator (19 mm) was used. The half-cell was assembled into a CR2032 coin cell (20 mm). 30 μL of electrolyte solution was added to the coin cell (EC / EMC v / v 50:50 1 M LiPF6). A commercially available NMC622 cathode with PVDF wet slurry was purchased for comparison.

[0148] Equipment: Coin cells were cycled using a Neware battery tester. Figures 7, 8, and 9 are rate capability tests for half cells containing NMC622, Super P, and a specific fluoropolymer binder. The rate capability tests show how well Li+ diffuses within the battery electrodes at various charge / discharge rates. All 1C = 1 hour charge / discharge cells were cycled at room temperature between 2.5 and 4.2 V vs. Li / Li. + It was cycled with.

[0149] Quantification: Capacity retention was calculated by specific capacity / initial specific capacity x 100 = % capacity remaining after x cycles.

[0150] Discussion of the cathode experiment results: The data presented in Figure 7 show that the relatively high molecular weight (melt creep viscosity) tetrafluoroethylene homopolymer Comparative Example PTFE1 tends to exhibit reduced performance, especially at a cycle rate of 1C. When PFA (Comparative Example PFA1) is added to the Comparative Example PTFE1 structure by the co-coagulation method, the performance of the high-loading cathode is comparable to that of a low-loading PVDF wet slurry commercial cathode. The inventors believe this is a surprising and significant result, suggesting that the present fluoropolymer composition can produce higher-loading cathode structures with reversible capacity retention. In addition, the exemplary Examples PTFE1 + 5% PFA1 and PTFE1 + 10% PFA1 have higher discharge capacities after the initial formation cycle compared to conventional PVDF wet slurry electrodes.

[0151] The data presented in Figure 8 shows that Comparative Example PTFE3 performs poorly at high cycle rates, but when co-coagulated with PFA1 by this method, the resulting Exemplary Example PTFE3+5%PFA1 has an increase of about 100 mAh / g at 1 C. Exemplary Example PTFE3+5%PFA1 has a reversible specific capacity under rate capability testing that performs better than the comparative PVDF wet slurry low loading electrode.

[0152] FIG. 9 shows the discharge specific capacity (mAh / g) versus cycle number for Comparative Example PTFE3, Example PTFE3+5%FKM1, Example PTFE3+5%FKM3, and Example PTFE3+5%FKM4. The data presented in FIG. 9 indicates that Comparative Example PTFE3 has a higher discharge specific capacity at C-rates less than C / 2. It is believed that the co-coagulated binder results in an improved electrode microstructure, increasing the discharge specific capacity as the C-rate increases. PTFE-FKM materials have comparable discharge specific capacities at C-rates less than C / 2. While not wishing to be bound by theory, it is believed that the differences in the molecular structure of the PTFE-FKM materials lead to positive variations in processing characteristics (i.e., blend homogeneity) and performance metrics that are uniquely exhibited at 1C. Furthermore, the friable nature of the PTFE-FKM materials, when optimally processed, allows for high-loading cathodes (e.g., 30 mg / cm).2 It would be advantageous to achieve higher rate capabilities for commercial battery applications requiring

[0153] anode The fluoropolymer composition was used to prepare test anodes according to the following procedure: Mixing: 1. Weigh out materials for a 10g batch with a composition of 90% graphite, 5% Super P conductive carbon, and 5% PTFE (or a fluoropolymer composition of the present invention). 2. Mix the graphite and Super P in a mortar and pestle for 15 minutes. 3. Add the graphite and Super P mixture and PTFE to a 250mL plastic bottle with 10 beads (1 bead / g material). 4. Set the roll mill speed to 55, place the bottle in the holder, and seal the top with tape. Leave on the roller for 30 minutes. 4. After 30 minutes, remove the beads from the anode mix and gently scrape down any material that has adhered to the sides of the bottle.

[0154] Anode Film Formation: The anode electrode mixture (3 g) was added to an 8 oz. glass mortar and pestle and crushed at room temperature until flakes formed. The flakes were placed on a hot plate heated to 100°C and spread using a steel roller heated to 100°C to create a stronger and more uniform initial film.

[0155] Calendering: The film was then directly calendered on calendering rolls heated to 50°C to reduce the film thickness. The roll gap distance started at 300 μm and was gradually reduced 100 μm at a time to 100 μm, then to 50 μm. The film was then passed 2 to 10 times through each gap, with the number of passes increasing as the gap decreased. The film was calendered in this manner until it reached a thickness of 70 to 90 μm.

[0156] Anode Lamination: 1. Cut a piece of copper foil, wipe both sides with IPA, and allow to dry. 2. Pour copper etching solution into a glass tray. Place one side of the copper foil in the etching solution for 10 seconds. 3. Transfer the copper foil to another glass tray filled with DI water and allow to soak for 1 minute. Rinse the copper foil thoroughly with DI water and allow to dry on a blue napkin. 4. Store the etched copper in a dry box when not in use; otherwise, the copper will oxidize if left outside. 5. Plasma treat the etched copper. 6. Heat a hot press to 300°C. Place the anode film on the copper foil and place it between two sheets of metal shims. Place the metal shims on a steel backing plate. 7. Press at 5,000 pounds for 5 minutes. 8. Remove it from the hot press and allow to cool before removing the metal shims. The shims may adhere slightly to the anode.

[0157] Cyclic voltammetry measurements: Electrode disks (15 mm diameter) were punched and dried overnight in a vacuum oven at 120 °C. Each electrode was used to assemble a 2032-type coin cell with a lithium metal counter electrode. A single-layer polypropylene Celgard film separator and a 1.2 M LiPF6 in EC / DEC (volume ratio 3:7) with 5% FEC additive electrolyte were used in the coin cell. Cyclic voltammetry was measured with a Bio-Logic potentiostat. The cyclic voltammetry test consisted of scanning the potential from 0 to 1.5 V vs. Li metal at a scan rate of 0.1 mV / s. The first loop of the obtained data is plotted from 0 to 1.4 V, including both the oxidation and reduction peaks, as shown in Figures 10 and 11.

[0158] Cyclic voltammetry reveals the oxidation and reduction characteristics of the electrode components. The reduction signal between 0.9 and 0.3 V is assigned to the degradation of the tetrafluoroethylene polymer. The signal (reduction) near 0.1 V represents the lithiation of graphite. The oxidation signal near 0.2 V represents the delithiation of graphite. While the reduction of the tetrafluoroethylene polymer PTFE is an irreversible process, graphite reversibly reduces and oxidizes when the current alternates from negative to positive. The reduction of the tetrafluoroethylene polymer PTFE reduces the bonding properties of the tetrafluoroethylene polymer, thereby leading to poor battery performance. To quantify the reduction (or degradation) of the fluoropolymer, the integrated area under the x-axis can be calculated by multiplying the voltage and normalized current and summing them over the voltage range of 0.9 to 0.3 V. The percent improvement or reduction in the degradation of the fluoropolymer in the anode composition can be calculated using the integrated current in the cyclic voltammetry test. The percentage improvement or reduction in degradation can be expressed as 100×(1−(integral current of the example) / integral current of the comparative example)).

[0159] Without wishing to be bound by theory, the inventors believe that the reduction peak between 0.3 V and 0.9 V is associated with PTFE decomposition and the formation of inactive LiF-like compounds. PTFE decomposition degrades the bonding properties of PTFE, leading to poor electrode cohesion and adhesion, and therefore poor battery performance. With reference to Figure 10, compared to Comparative Example PTFE1, both the binder samples of Example PTFE2+5%FKM2 and Example PTFE3+5%PFA1 exhibited lower decomposition / reduction currents, indicating that the FKM and PFA-modified binders provide better battery electrode bonding properties than the corresponding pure PTFE. With reference to Figure 11, compared to Comparative Example PTFE3, both the binder samples of Example PTFE3+5%FKM1 and Example PTFE3+5%PFA1 exhibited lower decomposition / reduction currents, indicating that the FKM and PFA-modified binders provide better battery electrode bonding properties than the corresponding pure PTFE.

[0160] Referring to Figure 12, the reduction of PTFE in a lithium-ion battery graphite anode can also be measured in terms of the first-cycle Coulombic efficiency of a graphite anode half cell. Lower values ​​of Coulombic efficiency indicate greater PTFE reduction in the anode. Binders that provide higher Coulombic efficiency for graphite anode half cells result from less PTFE reduction during lithium intercalation into the graphite. Here, we compare the Coulombic efficiency of graphite anodes fabricated using a binder composition equivalent to Comparative Example PTFE3+5%FKM1 (CG), but mixed by cryo-grinding (CG) rather than co-coagulation from an aqueous dispersion, with that of Example PTFE3+FKM1 (CC) co-coagulated (CC) binder. Both of these anodes contain the same composition of activated graphite, SP carbon, and the present fluoropolymer binder in a weight ratio of 90:5:5. The significantly higher values ​​of Coulombic efficiency of the anode fabricated with Example PTFE3+5%FKM1 (CC) compared to the anode produced with the binder comparative Example PTFE3+FKM1 (CG) prepared by cryogenic fracturing indicate that the PTFE binder obtained by co-coagulation is more electrochemically stable in the anode voltage region compared to the PTFE binder sample obtained by a physical mixing process such as cryogenic fracturing.

[0161] Cryogenic crushing comparison procedure Cryofractured samples were prepared using a SPEX 6875 Freezer / Mill® high-volume cryofracturer (Cole-Parmer, Metuchen, NJ 08840). Samples (5 grams) were placed in cryofractured tubes containing striker pins. The tubes were placed in the cryofractured holder, and the cryofractured tube was closed and locked. The cryofractured settings were 4 minutes of cooling, followed by 10 minutes of cryofractured. After 2 minutes of cooling, another 10 minutes of cryofractured was then repeated, resulting in a cryofractured sample.

[0162] Anode binder rate performance The rate capability test measures the charge / discharge rate of Li in the battery electrodes at various charge / discharge rates.+ This shows how well the charge / discharge rate of the ZnO / AlN alloy is distributed. 1C = 1 hour charge / discharge. All cells were cycled at room temperature.

[0163] For comparison, a slurried graphite electrode was prepared using a conventional polyvinylidene fluoride (PVDF) binder. The desired amounts of SP carbon and graphite active anode materials were mixed in a mortar and pestle for 15 minutes, then mixed for an additional 30 minutes using a roller mixer and zirconia milling balls (1 ball per 1 gm of material). N-methyl-2-pyrrolidone (NMP) and PVDF were mixed separately to obtain a thick solution. A certain amount of NMP / PVDF solution was added to the powder mixture, and additional amounts of NMP were added to maintain a usable (e.g., pourable) viscosity slurry. The final mixture was mixed in a THINKY mixer at 2000 RPM for 2 minutes, with several minutes of pause between each, for a total of three times. A finely mixed, viscous slurry was obtained. The slurry was manually poured onto a copper foil current collector using a doctor blade. The wet laminate was transferred to a hot air oven at 54 °C and maintained for at least 2 hours to obtain a dry PVDF binder anode electrode sheet. Circular electrode disks were punched out and dried at 120 °C overnight before cell assembly.

[0164] The data presented in Figure 13 show the rate test results of a second polymer co-coagulated with comparative polytetrafluoroethylene Comparative Example PTFE3 and Comparative Example PVDF wet slurry anodes. By adding PFA (Comparative Example PFA1) to Comparative Example PTFE3 and FKM (Comparative Example FKM1) to the Comparative Example PTFE3 structure using this co-coagulation method, the resulting co-coagulated fluoropolymer binders of the present invention, Examples PTFE3 + 5% PFA1 and PTFE3 + 5% FKM1, exhibited improved rate performance, particularly at a cycling rate of C / 5. Additionally, the Examples PTFE3 + 5% PFA1 and PTFE3 + 5% FKM1 have higher capacity than the polytetrafluoroethylene homopolymer Comparative Example PTFE3 and Comparative Example PVDF wet slurry electrodes. The inventors believe this is a surprising and significant result, suggesting that the present fluoropolymer binder composition enables highly loaded anode structures with reversible capacity retention.

[0165] SEM Image Sample Preparation and Interpretation: Electrode preparation: 10 g of electrode material (85% PTFE and 15% Super P conductive carbon) was placed in a 250 mL plastic bottle with 10 beads. The PTFE used was Comparative Example PTFE1 and Example PTFE3 + 5% PFA1. The mixture was ball milled for 30 minutes at a roll mill speed of 55 rpm. A 3 g amount of the mixture was calendered into a film through a hot calender roll (50 °C) (TMAXCN vertical calender) to obtain a thickness of 200-250 μm.

[0166] Cell preparation / testing and electrode preparation: Freestanding electrode discs (15 mm diameter) were punched and dried at 120 °C under vacuum for at least 8 hours. 2032-type coin cells were assembled using a lithium metal counter electrode, Celgard 2400 separator, and 1.0 M LiPF6 in EC / EMC (1:1 volume ratio, Gotion) electrolyte. The coin cells were cycled for two cycles at a constant current of C / 25 from 0.01 V to 1.25 V on a Neware cell tester. Completed cells were opened in a N2 glove bag using a TMAX coin cell de-crimper. Cycled electrodes were collected for SEM examination. SEM images were taken from above on a Zeiss Auriga 60 CrossBeam (FE-SEM) on a freshly cycled electrode.

[0167] Discussion of anode experimental results: SEM photographs in Figures 14-17 show electrodes before and after two charge-discharge cycles, providing direct evidence of PTFE fibril stability against reduction. Long PTFE fibrils are observed for both the pristine electrodes of Comparative Example PTFE1 and Example PTFE3+5%PFA1 (see Figures 14 and 16). The length of the PTFE fibrils in the pristine Comparative Example PTFE1 is 30-50 μm. After two cycles, the fibrils have deteriorated to 4-8 μm (see Figure 15). Fibril degradation deteriorates the PTFE's cohesive strength and can lead to mechanical failure of the electrode. In contrast, the fibril length (30-40 μm) of Example PTFE3+5% PFA1 in the initial state (see FIG. 16) was still maintained after two cycles (see FIG. 17), indicating that Example PTFE3+5% PFA1 is much more stable to reduction, which is an important property for maintaining electrode adhesion and cohesion as an anode binder. In summary, by comparing the SEM images of the electrode before and after cycling, Example PTFE3+5% PFA1 is significantly more stable than Comparative Example PTFE1 (unmodified PTFE) from the perspective of reduction under the conditions encountered in the anode of a lithium-ion secondary battery.

Claims

1. 1. A fluoropolymer composition for use as a binder in a lithium ion secondary battery electrode, comprising dried, friable agglomerates, the dried, friable agglomerates comprising: i.) at least about 0.5 x 10 １１ a first polymer comprising a tetrafluoroethylene polymer having a melt creep viscosity of poise; ii.) a second polymer different from said first polymer.

2. The composition of claim 1 , wherein the agglomerates comprise particles of the first polymer and particles of the second polymer.

3. The composition of claim 1 , wherein the aggregate is prepared by co-coagulation of an aqueous dispersion of the first polymer and an aqueous dispersion of the second polymer.

4. 4. The composition of claim 3, wherein the agglomerate is prepared by: I.) co-coagulating an aqueous dispersion of the first polymer and an aqueous dispersion of the second polymer to produce an agglomerate comprising the first polymer and the second polymer; II.) separating the agglomerate from the aqueous phase; and III.) drying the agglomerate.

5. The composition of claim 3 , wherein the co-coagulation is chemical co-coagulation.

6. 2. The composition of claim 1, wherein the disintegrability of the agglomerates is characterized by the ability of the agglomerates to be deagglomerated and broken down by application of shear forces without substantially fibrillating the tetrafluoroethylene polymer.

7. 10. The composition of claim 1, wherein the shear force applied to the agglomerates results in deagglomeration and pulverization of the agglomerates without substantially fibrillating the tetrafluoroethylene polymer to form secondary agglomerates having an average particle size of from about 10 to about 300 micrometers.

8. 10. The composition of claim 1, wherein the shear force applied to the agglomerates results in deagglomeration and pulverization of the agglomerates without substantially fibrillating the tetrafluoroethylene polymer to form secondary agglomerates having an average particle size of from about 10 to about 60 micrometers.

9. 2. The composition of claim 1, wherein the second polymer is selected from the group consisting of fluoropolymers, polyolefins, polyesters, polyamides, polyimides, polyaramids, polyacrylates, polyurethanes, polyethers, polyol ethers, polyacrylonitriles, polyphosphazenes, polysiloxanes, polysulfides, and polysulfones having a melt creep viscosity different from that of the first polymer.

10. 2. The composition of claim 1, wherein the second polymer is selected from the group consisting of tetrafluoroethylene polymer, tetrafluoroethylene perfluoro(alkyl vinyl ether) (PFA), fluorinated ethylene propylene (FEP), fluoroelastomer (FKM), ethylene tetrafluoroethylene polymer (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (CTFE), and polyvinyl fluoride (PVF), having a melt creep viscosity different from that of the first polymer.

11. 10. The composition of claim 1, wherein the weight ratio of said tetrafluoroethylene polymer to said second polymer is from about 99:1 to about 50:

50.

12. 10. The composition of claim 1, wherein the weight ratio of said tetrafluoroethylene polymer to said second polymer is from about 99:1 to about 80:

20.

13. 10. The composition of claim 1, wherein the weight ratio of said tetrafluoroethylene polymer to said second polymer is from about 99:1 to about 90:

10.

14. 10. The composition of claim 1, wherein the weight ratio of said tetrafluoroethylene polymer to said second polymer is from about 99:1 to about 95:

5.

15. 10. The composition of claim 1, wherein the weight ratio of said tetrafluoroethylene polymer to said second polymer is from about 98:2 to about 92:

8.

16. 10. The composition of claim 1, wherein the weight ratio of said tetrafluoroethylene polymer to said second polymer is about 90:

10.

17. 10. The composition of claim 1, wherein the weight ratio of said tetrafluoroethylene polymer to said second polymer is about 95:

5.

18. The composition of claim 1 , wherein the second polymer is a tetrafluoroethylene perfluoro(alkyl vinyl ether) (PFA) polymer.

19. 19. The composition of claim 18, wherein the weight ratio of said tetrafluoroethylene polymer to said tetrafluoroethylene perfluoro(alkyl vinyl ether) polymer is from about 99:1 to about 50:

50.

20. 19. The composition of claim 18, wherein the weight ratio of said tetrafluoroethylene polymer to said tetrafluoroethylene perfluoro(alkyl vinyl ether) polymer is from about 99:1 to about 90:

10.

21. 19. The composition of claim 18, wherein the weight ratio of said tetrafluoroethylene polymer to said tetrafluoroethylene perfluoro(alkyl vinyl ether) polymer is from about 98:2 to about 92:

8.

22. The composition of claim 1 , wherein the second polymer is a fluoroelastomer (FKM).

23. 23. The composition of claim 22, wherein the weight ratio of said tetrafluoroethylene polymer to said fluoroelastomer is from about 99:1 to about 80:

20.

24. The composition of claim 1, wherein the aggregates have an average particle size of about 200 to about 1000 micrometers.

25. The composition of claim 1, wherein the aggregates have an average particle size of about 200 to about 500 micrometers.

26. The tetrafluoroethylene polymer has a viscosity of at least about 0.5×10 １１ Poise to approximately 6.0 x 10 １１ 10. The composition of claim 1 having a melt creep viscosity in poise.

27. 2. The composition of claim 1, wherein the tetrafluoroethylene polymer is a tetrafluoroethylene homopolymer consisting essentially of tetrafluoroethylene monomer repeat units.

28. 10. The composition of claim 1, wherein the tetrafluoroethylene polymer is a modified tetrafluoroethylene polymer comprising tetrafluoroethylene monomer repeat units and up to about 1 weight percent modifying comonomer (modifier) ​​repeat units.

29. 10. The composition of claim 1, wherein the aggregates are composed of tetrafluoroethylene polymer primary particles and second polymer primary particles.

30. 30. The composition of claim 29, wherein the primary particles have an average particle size of about 5 nm to about 250 nm.

31. The composition of claim 1 , wherein the composition is substantially solvent-free.

32. The composition of any one of claims 1 to 31, wherein the tetrafluoroethylene polymer is substantially non-fibrillated.

33. 1. A method for producing an electrode composition for use in a lithium ion secondary battery electrode, comprising: IV.) milling electrode active particles together with dried, disintegrable agglomerates to form said electrode composition comprising fibrillated tetrafluoroethylene polymer; The dried, disintegratable agglomerates are i.) at least about 0.5 x 10 １１ a first polymer comprising a non-fibrillating tetrafluoroethylene polymer having a melt creep viscosity of poise; ii.) a second polymer different from said first polymer.

34. Before the grinding step, I.) A co-coagulation step, I.-i) at least about 0.5 x 10 １１ an aqueous dispersion of a first polymer comprising a non-fibrillating tetrafluoroethylene polymer having a melt creep viscosity of poise; I.-ii) a second polymer different from the first polymer; and to form disintegratable agglomerates of the first polymer and the second polymer; II.) Separating the disintegrable agglomerates from the aqueous phase; III.) drying the disintegrable agglomerates; 34. The method of claim 33, wherein the dry, friable agglomerates comprising particles of the first polymer and the second polymer are formed by performing

35. 34. The method of claim 33, wherein the disintegratable agglomerates have an average particle size of about 200 to about 1000 micrometers.

36. 34. The method of claim 33, wherein the disintegratable agglomerates have an average particle size of about 200 to about 500 micrometers.

37. IV.) The method of claim 33, further comprising, prior to the grinding step, pre-grinding the dry, friable agglomerates sufficient to deagglomerate and grind the dry, friable agglomerates without substantially fibrillating the tetrafluoroethylene polymer.

38. 38. The method of claim 37, wherein the pre-grinding results in the formation of secondary agglomerates having an average particle size of about 10 to about 300 micrometers.

39. 38. The method of claim 37, wherein the pre-grinding results in the formation of secondary agglomerates having an average particle size of about 10 to about 60 micrometers.

40. 34. The method of claim 33, wherein said IV.) grinding is sufficient to deagglomerate and break up said agglomerates, resulting in the formation of secondary agglomerates having an average particle size of about 10 to about 300 micrometers.

41. 34. The method of claim 33, wherein said IV.) grinding is sufficient to deagglomerate and break up said agglomerates, resulting in the formation of secondary agglomerates having an average particle size of about 10 to about 60 micrometers.

42. 34. The method of claim 33, wherein said IV.) grinding is carried out substantially solvent-free.

43. 35. The method of claim 34, wherein the tetrafluoroethylene polymer is substantially non-fibrillated during the steps I.) co-coagulating, II.) separating, and III.) drying.

43. 34. The method of claim 33, wherein the tetrafluoroethylene polymer is fibrillated during the IV.) grind.

44. 34. The method of claim 33, wherein the temperature of said IV.) milled powder is from about 20°C to about 200°C.

45. 34. The method of claim 33, wherein the temperature of said IV.) milled powder is from about 80°C to about 150°C.

46. 35. The method of claim 34, wherein said I.) co-coagulating is carried out using an aqueous dispersion of particles of said first polymer and an aqueous dispersion of particles of said second polymer, and said disintegrable agglomerates comprise particles of said first polymer and particles of said second polymer.

47. 35. The method of claim 34, wherein the co-coagulation is chemical co-coagulation.

48. 34. The method of claim 33, wherein the second polymer is selected from the group consisting of fluoropolymers, polyolefins, polyesters, polyamides, polyimides, polyaramids, polyacrylates, polyurethanes, polyethers, polyol ethers, polyacrylonitriles, polyphosphazenes, polysiloxanes, polysulfides, and polysulfones having a melt creep viscosity different from the melt creep viscosity of the first polymer.

49. 34. The method of claim 33, wherein the second polymer is selected from the group consisting of tetrafluoroethylene polymer, tetrafluoroethylene perfluoro(alkyl vinyl ether) (PFA), fluorinated ethylene propylene (FEP), fluoroelastomer (FKM), ethylene tetrafluoroethylene polymer (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (CTFE), and polyvinyl fluoride (PVF), having a melt creep viscosity different from the melt creep viscosity of the first polymer.

50. 34. The method of claim 33, wherein the second polymer comprises a tetrafluoroethylene perfluoro(alkyl vinyl ether) (PFA) polymer.

51. 34. The method of claim 33, wherein the second polymer comprises a fluoroelastomer (FKM).

52. The tetrafluoroethylene polymer has a viscosity of at least about 0.5×10 １１ Poise to approximately 6.0 x 10 １１ 34. The method of claim 33, having a melt creep viscosity in poise.

53. 34. The method of claim 33, wherein the tetrafluoroethylene polymer is a tetrafluoroethylene homopolymer consisting essentially of tetrafluoroethylene monomer repeat units.

54. 34. The method of claim 33, wherein the tetrafluoroethylene polymer is a modified tetrafluoroethylene polymer comprising tetrafluoroethylene monomer repeat units and about 1 weight percent or less of modifying comonomer (modifier) ​​repeat units.

55. 34. The method of claim 33, wherein the aggregates are composed of tetrafluoroethylene polymer primary particles and tetrafluoroethylene perfluoro(alkyl vinyl ether) polymer primary particles, the primary particles having an average particle size of about 5 nm to about 250 nm.

56. 34. The method of claim 33, wherein the agglomerates are comprised of tetrafluoroethylene polymer primary particles and fluoroelastomer (FKM) polymer primary particles, the primary particles having an average particle size of about 5 nm to about 250 nm.

57. 34. The method of claim 33, wherein the weight ratio of the tetrafluoroethylene polymer to the second polymer is from about 99:1 to about 50:

50.

58. 34. The method of claim 33, wherein the weight ratio of the tetrafluoroethylene polymer to the second polymer is from about 99:1 to about 80:

20.

59. 34. The method of claim 33, wherein the weight ratio of the tetrafluoroethylene polymer to the second polymer is from about 99:1 to about 90:

10.

60. 34. The method of claim 33, wherein the weight ratio of the tetrafluoroethylene polymer to the second polymer is from about 99:1 to about 95:

5.

61. 34. The method of claim 33, wherein the weight ratio of the tetrafluoroethylene polymer to the second polymer is from about 98:2 to about 92:

8.

62. 34. The method of claim 33, wherein the weight ratio of the tetrafluoroethylene polymer to the second polymer is about 90:

10.

63. 34. The method of claim 33, wherein the weight ratio of the tetrafluoroethylene polymer to the second polymer is about 95:

5.

64. 34. An electrode composition for use in a lithium ion secondary battery electrode, produced by the method of claim 33.

65. 1. A composition for use in a lithium ion secondary battery cathode film, comprising: i.) cathode active particles comprising a lithium transition metal oxide; and ii.) conductive carbon; and iii.) at least about 0.5 x 10 １１ a fluoropolymer binder comprising a mixture of particles of a tetrafluoroethylene polymer having a melt creep viscosity of poise and particles of a second polymer, wherein the tetrafluoroethylene polymer is fibrillated.

66. 66. The composition of claim 65, wherein the second polymer is selected from the group consisting of fluoropolymers, polyolefins, polyesters, polyamides, polyimides, polyaramids, polyacrylates, polyurethanes, polyethers, polyol ethers, polyacrylonitriles, polyphosphazenes, polysiloxanes, polysulfides, and polysulfones having a melt creep viscosity different from the melt creep viscosity of the first polymer.

67. 66. The composition of claim 65, wherein the second polymer is selected from the group consisting of tetrafluoroethylene polymer, tetrafluoroethylene perfluoro(alkyl vinyl ether) (PFA), fluorinated ethylene propylene (FEP), fluoroelastomer (FKM), ethylene tetrafluoroethylene polymer (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (CTFE), and polyvinyl fluoride (PVF), having a melt creep viscosity different from the melt creep viscosity of the first polymer.

68. 66. The composition of claim 65, wherein the second polymer comprises particles of tetrafluoroethylene perfluoro(alkyl vinyl ether) polymer.

69. 66. The composition of claim 65, wherein the second polymer comprises particles of a fluoroelastomer (FKM).

70. 66. The composition of claim 65, wherein the fluoropolymer binder is prepared by co-coagulation of an aqueous dispersion of a first polymer with an aqueous dispersion of the second polymer.

71. 71. The composition of claim 70, wherein the co-coagulation is chemical co-coagulation.

72. 66. The composition of claim 65, wherein the composition is prepared by milling dry, friable agglomerates comprising the cathode active particles, the conductive carbon, and the fluoropolymer binder, thereby fibrillating the fluoropolymer binder.

73. 73. The composition of claim 72, wherein the grinding is carried out substantially free of solvent.

74. 66. The composition of claim 65, wherein the composition contains about 1 to about 10 weight percent of the fluoropolymer binder, about 95 to about 98 weight percent of the cathode active particles, and about 1 to about 10 weight percent of the conductive carbon, based on the combined weight of the fluoropolymer binder, the cathode active particles, and the conductive carbon.

75. 66. The composition of claim 65, wherein the weight ratio of the tetrafluoroethylene polymer to the second polymer is from about 99:1 to about 50:

50.

76. 66. The composition of claim 65, wherein the weight ratio of the tetrafluoroethylene polymer to the second polymer is from about 99:1 to about 80:

20.

77. 66. The composition of claim 65, wherein the weight ratio of the tetrafluoroethylene polymer to the second polymer is from about 99:1 to about 90:

10.

78. 66. The composition of claim 65, wherein the weight ratio of the tetrafluoroethylene polymer to the second polymer is from about 99:1 to about 95:

5.

79. 66. The composition of claim 65, wherein the weight ratio of the tetrafluoroethylene polymer to the second polymer is from about 98:2 to about 92:

8.

80. 66. The composition of claim 65, wherein the weight ratio of the tetrafluoroethylene polymer to the second polymer is about 90:

10.

81. 66. The composition of claim 65, wherein the weight ratio of the tetrafluoroethylene polymer to the second polymer is about 95:

5.

82. 1. A composition for use in a lithium ion secondary battery anode film, comprising: i.) anode active particles; and iii.) at least about 0.5 x 10 １１ a fluoropolymer binder comprising a mixture of particles of a tetrafluoroethylene polymer having a melt creep viscosity of poise and particles of a second polymer, wherein the tetrafluoroethylene polymer is fibrillated.

83. 83. The composition of claim 82, wherein the second polymer is selected from the group consisting of fluoropolymers, polyolefins, polyesters, polyamides, polyimides, polyaramids, polyacrylates, polyurethanes, polyethers, polyol ethers, polyacrylonitriles, polyphosphazenes, polysiloxanes, polysulfides, and polysulfones having a melt creep viscosity different from the melt creep viscosity of the first polymer.

84. 83. The composition of claim 82, wherein the second polymer is selected from the group consisting of tetrafluoroethylene polymer, tetrafluoroethylene perfluoro(alkyl vinyl ether) (PFA), fluorinated ethylene propylene (FEP), fluoroelastomer (FKM), ethylene tetrafluoroethylene polymer (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (CTFE), and polyvinyl fluoride (PVF), having a melt creep viscosity different from the melt creep viscosity of the first polymer.

85. 83. The composition of claim 82, wherein the second polymer comprises particles of tetrafluoroethylene perfluoro(alkyl vinyl ether) polymer.

86. 83. The composition of claim 82, wherein the second polymer comprises particles of a fluoroelastomer (FKM).

87. 83. The composition of claim 82, wherein the fluoropolymer binder is prepared by co-coagulation of an aqueous dispersion of a first polymer with an aqueous dispersion of the second polymer.

88. 83. The composition of claim 82, wherein the co-coagulation is chemical co-coagulation.

89. 83. The composition of claim 82, wherein the composition is prepared by comminuting the anode active particles and dry, friable agglomerates comprising the fluoropolymer binder, thereby fibrillating the fluoropolymer binder.

90. 83. The composition of claim 82, wherein the milling is carried out substantially free of solvent.

91. 83. The composition of claim 82, wherein the composition contains from about 1 to about 10 weight percent fluoropolymer binder, from about 90 to about 99 weight percent anode active particles.

92. 83. The composition of claim 82, wherein the weight ratio of the tetrafluoroethylene polymer to the second polymer is from about 99:1 to about 50:

50.

93. 83. The composition of claim 82, wherein the weight ratio of the tetrafluoroethylene polymer to the second polymer is from about 99:1 to about 80:

20.

94. 83. The composition of claim 82, wherein the weight ratio of the tetrafluoroethylene polymer to the second polymer is from about 99:1 to about 90:

10.

95. 83. The composition of claim 82, wherein the weight ratio of the tetrafluoroethylene polymer to the second polymer is from about 99:1 to about 95:5.

49.

96. 83. The composition of claim 82, wherein the weight ratio of the tetrafluoroethylene polymer to the second polymer is from about 98:2 to about 92:

8.

97. 83. The composition of claim 82, wherein the weight ratio of the tetrafluoroethylene polymer to the second polymer is about 90:

10.

98. 83. The composition of claim 82, wherein the weight ratio of the tetrafluoroethylene polymer to the second polymer is about 95:

5.

99. A lithium ion secondary battery, 1) A cathode comprising a cathode electrode layer affixed to a metal current collector, the cathode electrode layer comprising a cathode electrode composition; The cathode electrode composition comprises: a) cathode active particles comprising a lithium transition metal oxide; b) conductive carbon, and c) a fluoropolymer binder, i) at least about 0.5 x 10 １１ particles of a tetrafluoroethylene polymer having a melt creep viscosity of poise; ii) a cathode comprising a fluoropolymer binder containing a mixture with particles of a second polymer; 2) an anode; 3) a separator between the cathode and the anode; 4) A lithium ion secondary battery comprising the cathode, the anode, and an electrolyte in communication with the separator.

100. 100. The battery of claim 99, wherein the battery has a higher discharge specific capacity at a given C-rate of at least C / 2 greater than an identical battery in which the fluoropolymer binder does not contain the second polymer.

101. 100. The battery of claim 99, wherein the battery has at least 50% higher discharge specific capacity at a given C-rate of at least C / 2 greater than an identical battery in which the fluoropolymer binder does not contain the second polymer.

102. 100. The battery of claim 99, wherein the battery has at least 100% higher discharge specific capacity at a given C-rate of at least C / 2 greater than an identical battery in which the fluoropolymer binder does not contain the second polymer.

103. 100. The battery of claim 99, wherein the battery has at least 150% higher discharge specific capacity at a given C-rate of at least C / 2 greater than an identical battery in which the fluoropolymer binder does not contain the second polymer.

104. 100. The battery of claim 99, wherein the battery has at least 200% higher discharge specific capacity at a given C-rate at a C-rate of at least C / 2 greater than an identical battery in which the fluoropolymer binder does not contain the second polymer.

105. 100. The battery of claim 99, wherein the battery has at least 250% higher discharge specific capacity at a given C-rate at a C-rate of at least C / 2 greater than an identical battery in which the fluoropolymer binder does not contain the second polymer.

106. 100. The battery of claim 99, wherein the fluoropolymer binder is prepared by co-coagulation of an aqueous dispersion of the tetrafluoroethylene polymer with an aqueous dispersion of the second polymer.

107. 107. The battery of claim 106, wherein the fluoropolymer binder is prepared by: I.) co-coagulating an aqueous dispersion of the tetrafluoroethylene polymer with an aqueous dispersion of the second polymer to produce disintegrable agglomerates of the tetrafluoroethylene polymer and the second polymer; II.) separating the agglomerates from the aqueous phase; and III.) drying the agglomerates.

108. 107. The battery of claim 106, wherein the co-coagulation is chemical co-coagulation.

109. 108. The battery of claim 107, wherein the disintegrability of the agglomerates is characterized by the ability of the agglomerates to be disaggregated and broken down by application of shear forces without substantially fibrillating the tetrafluoroethylene polymer.

110. 108. The battery of claim 107, wherein the shear force applied to the agglomerates results in deagglomeration and pulverization of the agglomerates without substantially fibrillating the tetrafluoroethylene polymer to form secondary agglomerates having an average particle size of about 10 to about 300 micrometers.

111. 108. The battery of claim 107, wherein the shear force applied to the agglomerates results in deagglomeration and pulverization of the agglomerates without substantially fibrillating the tetrafluoroethylene polymer to form secondary agglomerates having an average particle size of about 10 to about 60 micrometers.

112. 100. The battery of claim 99, wherein the second polymer is selected from the group consisting of fluoropolymers, polyolefins, polyesters, polyamides, polyimides, polyaramids, polyacrylates, polyurethanes, polyethers, polyol ethers, polyacrylonitriles, polyphosphazenes, polysiloxanes, polysulfides, and polysulfones having a melt creep viscosity different from the melt creep viscosity of the first polymer.

113. 100. The battery of claim 99, wherein the second polymer is selected from the group consisting of tetrafluoroethylene polymer, tetrafluoroethylene perfluoro(alkyl vinyl ether) (PFA), fluorinated ethylene propylene (FEP), fluoroelastomer (FKM), ethylene tetrafluoroethylene polymer (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (CTFE), and polyvinyl fluoride (PVF) having a melt creep viscosity different from the melt creep viscosity of the first polymer.

114. 100. The battery of claim 99, wherein the second polymer comprises particles of a tetrafluoroethylene perfluoro(alkyl vinyl ether) polymer.

115. 100. The battery of claim 99, wherein the second polymer comprises particles of a fluoroelastomer (FKM).

116. 100. The battery of claim 99, wherein the cathode electrode composition is prepared by milling dry, friable agglomerates comprising the cathode active particles, the conductive carbon, and the fluoropolymer binder, thereby fibrillating the tetrafluoroethylene polymer.

117. 117. The battery of claim 116, wherein the grinding is carried out substantially free of solvents.

118. 100. The battery of claim 99, wherein the composition contains about 1 to about 10 weight percent fluoropolymer binder, about 95 to about 98 weight percent cathode active particles, and about 1 to about 10 weight percent conductive carbon, based on the combined weight of the fluoropolymer binder, the cathode active particles, and the conductive carbon.

119. 100. The battery of claim 99, wherein the weight ratio of the tetrafluoroethylene polymer to the second polymer is from about 99:1 to about 50:

50.

120. 100. The battery of claim 99, wherein the weight ratio of the tetrafluoroethylene polymer to the second polymer is from about 99:1 to about 80:

20.

121. 100. The battery of claim 99, wherein the weight ratio of the tetrafluoroethylene polymer to the second polymer is from about 99:1 to about 90:

10.

122. 100. The battery of claim 99, wherein the weight ratio of the tetrafluoroethylene polymer to the second polymer is from about 99:1 to about 95:

5.

123. 100. The battery of claim 99, wherein the weight ratio of the tetrafluoroethylene polymer to the second polymer is from about 98:2 to about 92:

8.

124. 100. The battery of claim 99, wherein the weight ratio of the tetrafluoroethylene polymer to the second polymer is about 90:

10.

125. 100. The battery of claim 99, wherein the weight ratio of the tetrafluoroethylene polymer to the second polymer is about 95:

5.

126. the tetrafluoroethylene polymer is selected from the group consisting of: A) a tetrafluoroethylene homopolymer consisting essentially of tetrafluoroethylene monomer repeat units; and B) a modified tetrafluoroethylene polymer consisting essentially of tetrafluoroethylene monomer repeat units and about 1 weight percent or less of a modifying perfluoro(alkyl vinyl ether) comonomer repeat unit; 100. The battery of claim 99, wherein the second polymer comprises a tetrafluoroethylene perfluoro(alkyl vinyl ether) polymer.

127. A lithium ion secondary battery, 1) An anode comprising an anode electrode layer affixed to a metal current collector, the anode electrode layer comprising an anode electrode composition; The anode electrode composition comprises: a) anode active particles; b) a fluoropolymer binder, i) at least about 0.5 x 10 １１ particles of a tetrafluoroethylene polymer having a melt creep viscosity of poise; ii) an anode comprising a fluoropolymer binder containing a mixture with particles of a second polymer; 2) a cathode; and 3) a separator between the cathode and the anode; 4) A lithium ion secondary battery comprising the cathode, the anode, and an electrolyte in communication with the separator.

128. 128. The battery of claim 127, wherein the battery has a higher lithium desorption capacity (mAh / g) at a given C-rate than an identical battery in which the fluoropolymer binder does not contain the second polymer.

129. 128. The battery of claim 127, wherein the battery has a lithium desorption capacity (mAh / g) at a given C-rate that is at least 3% higher than an identical battery in which the fluoropolymer binder does not contain the second polymer.

130. 128. The battery of claim 127, wherein the battery has a lithium desorption capacity (mAh / g) at a given C-rate that is at least 5% higher than an identical battery in which the fluoropolymer binder does not contain the second polymer.

131. 128. The battery of claim 127, wherein the battery has a lithium desorption capacity (mAh / g) at a given C-rate that is at least 7% higher than an identical battery in which the fluoropolymer binder does not contain the second polymer.

132. 128. The battery of claim 127, wherein the battery has a lithium desorption capacity (mAh / g) at a given C-rate that is at least 10% higher than an identical battery in which the fluoropolymer binder does not contain the second polymer.

133. 128. The battery of claim 127, wherein the anode exhibits an electrochemical reduction of 0.25 V to 0.9 V vs. Li / Li+ by cyclic voltammetry measurement, where the fluoropolymer binder is reduced relative to an anode in an identical battery that does not contain the second polymer.

134. 128. The battery of claim 127, wherein the anode exhibits an electrochemical reduction by cyclic voltammetry measurement from 0.25 V to 0.9 V vs. Li / Li+ in which the fluoropolymer binder is reduced by at least about 30% relative to an anode in an identical battery not containing the second polymer.

135. 128. The battery of claim 127, wherein the anode exhibits an electrochemical reduction by cyclic voltammetry measurement from 0.25 V to 0.9 V vs. Li / Li+ in which the fluoropolymer binder is reduced by at least about 40% relative to an anode in an identical battery not containing the second polymer.

136. 128. The battery of claim 127, wherein the anode exhibits an electrochemical reduction by cyclic voltammetry measurement from 0.25 V to 0.9 V vs. Li / Li+ in which the fluoropolymer binder is reduced by at least about 50% relative to an anode in an identical battery not containing the second polymer.

137. 128. The battery of claim 127, wherein the anode exhibits an electrochemical reduction by cyclic voltammetry measurement from 0.25 V to 0.9 V vs. Li / Li+ in which the fluoropolymer binder is reduced by at least about 60% relative to an anode in an identical battery not containing the second polymer.

138. 128. The battery of claim 127, wherein the fluoropolymer binder is prepared by co-coagulation of an aqueous dispersion of the tetrafluoroethylene polymer with an aqueous dispersion of the second polymer.

139. 139. The battery of claim 138, wherein the fluoropolymer binder is prepared by: I.) co-coagulating an aqueous dispersion of the tetrafluoroethylene polymer with an aqueous dispersion of the second polymer to produce disintegrable agglomerates of the tetrafluoroethylene polymer and the second polymer; II.) separating the agglomerates from the aqueous phase; and III.) drying the agglomerates.

140. 139. The battery of claim 138, wherein the co-coagulation is chemical co-coagulation.

141. 140. The battery of claim 139, wherein the disintegrability of the agglomerates is characterized by the ability of the agglomerates to be disaggregated and broken down by application of shear forces without substantially fibrillating the tetrafluoroethylene polymer.

142. 140. The battery of claim 139, wherein the shear force applied to the agglomerates results in deagglomeration and pulverization of the agglomerates without substantially fibrillating the tetrafluoroethylene polymer to form secondary agglomerates having an average particle size of about 10 to about 300 micrometers.

143. 140. The battery of claim 139, wherein the shear force applied to the agglomerates results in deagglomeration and pulverization of the agglomerates without substantially fibrillating the tetrafluoroethylene polymer to form secondary agglomerates having an average particle size of about 10 to about 60 micrometers.

144. 128. The battery of claim 127, wherein the second polymer is selected from the group consisting of fluoropolymers, polyolefins, polyesters, polyamides, polyimides, polyaramids, polyacrylates, polyurethanes, polyethers, polyol ethers, polyacrylonitriles, polyphosphazenes, polysiloxanes, polysulfides, and polysulfones having a melt creep viscosity different from the melt creep viscosity of the first polymer.

145. 128. The battery of claim 127, wherein the second polymer is selected from the group consisting of tetrafluoroethylene polymer, tetrafluoroethylene perfluoro(alkyl vinyl ether) (PFA), fluorinated ethylene propylene (FEP), fluoroelastomer (FKM), ethylene tetrafluoroethylene polymer (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (CTFE), and polyvinyl fluoride (PVF) having a melt creep viscosity different from the melt creep viscosity of the first polymer.

146. 128. The battery of claim 127, wherein the second polymer comprises particles of tetrafluoroethylene perfluoro(alkyl vinyl ether) polymer.

147. 128. The battery of claim 127, wherein the second polymer comprises particles of a fluoroelastomer (FKM).

148. 128. The battery of claim 127, wherein the anode electrode composition is prepared by comminuting the anode active particles and dry, friable agglomerates comprising the fluoropolymer binder, thereby fibrillating the fluoropolymer binder.

149. 149. The battery of claim 148, wherein said grinding is carried out substantially free of solvents.

150. 128. The battery of claim 127, wherein the anode electrode composition contains from about 1 to about 10 weight percent fluoropolymer binder and from about 90 to about 99 weight percent anode active particles.

151. 128. The battery of claim 127, wherein the weight ratio of the tetrafluoroethylene polymer to the second polymer is from about 99:1 to about 50:

50.

152. 128. The battery of claim 127, wherein the weight ratio of the tetrafluoroethylene polymer to the second polymer is from about 99:1 to about 80:

20.

153. 128. The battery of claim 127, wherein the weight ratio of the tetrafluoroethylene polymer to the second polymer is from about 99:1 to about 90:

10.

154. 128. The battery of claim 127, wherein the weight ratio of the tetrafluoroethylene polymer to the second polymer is from about 99:1 to about 95:

5.

155. 128. The battery of claim 127, wherein the weight ratio of the tetrafluoroethylene polymer to the second polymer is from about 98:2 to about 92:

8.

156. 128. The battery of claim 127, wherein the weight ratio of the tetrafluoroethylene polymer to the second polymer is about 90:

10.

157. 128. The battery of claim 127, wherein the weight ratio of the tetrafluoroethylene polymer to the second polymer is about 95:5.

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