Silicon composite anode materials for energy storage devices and methods thereof

Abstract

A method for forming a dry composite material for an energy storage device electrode is provided. The method can include forming a slurry by mixing a solvent, a silicon active material, a carbon active material, and a carbon additive, and removing the solvent to form a dry composite material including the silicon active material, the carbon active material, and the carbon additive. The carbon additive, the silicon active material, and the carbon active material are substantially homogeneously dispersed in the dry composite material. The dry composite material can be used to form a dry electrode film in a dry fabrication process.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of U.S. Provisional Application No. 63 / 377,982, filed September 30, 2022, entitled SILICON COMPOSITE ANODE MATERIALS FOR ENERGY STORAGE DEVICES, AND METHODS THEREOF, which is incorporated herein by reference in its entirety.

[0002] The present invention relates generally to energy storage devices, and more particularly to materials and methods for dry electrode films containing silicon active material. [Background technology]

[0003] Lithium-ion batteries have been relied upon as power sources in numerous commercial and industrial applications, for example, in consumer devices, productivity devices, and battery-powered vehicles. One route to improving the storage potential of energy storage devices is to use active materials with high theoretical capacities, such as silicon, silicon oxide (SiO x One approach is to use silicon materials such as graphite (SiC), silicon-carbon (Si / C), or silicon-carbon composites (Si / C). Silicon has a theoretical capacity of approximately 3560 mAh / g, which is approximately 10 times the capacity of graphite at 356 mAh / g. However, electrode films can suffer from performance degradation due to the mechanical properties of the film components and the interactions between them. Specifically, further degradation can be observed in electrodes incorporating silicon materials, which can undergo significant volume changes during cell cycling.

[0004] One method used to maintain electrical contact during cycling of electrodes containing silicon materials is to use carbon additives, such as carbon nanotubes (CNTs) and carbon black, to form a carbon matrix across the electrode. In conventional wet electrode film processes, it may be possible to uniformly distribute the binder, graphite, carbon additive, and silicon material. However, without the use of processing solvents, it may be more difficult to uniformly distribute the binder, graphite, silicon material, and / or carbon additive. Therefore, new compositions and processes are needed to improve the dispersion of materials within the electrode film. Summary of the Invention [Problem to be solved by the invention]

[0005] 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 implemented to achieve or optimize one advantage or advantages as taught herein without necessarily achieving other objects or advantages that may be taught or suggested herein. [Means for solving the problem]

[0006] In one aspect, a dry composite material for an energy storage device is disclosed. The dry composite material includes a silicon active material, a carbon active material, and a carbon additive, wherein the carbon additive, the silicon active material, and the carbon active material are substantially homogeneously dispersed in the dry composite material.

[0007] In some embodiments, the carbon additive is selected from the group consisting of carbon nanotubes, carbon black, carbon nanofibers, and combinations thereof. In some embodiments, the carbon additive is a conductive additive. In some embodiments, the carbon additive forms a matrix.

[0008] In some embodiments, the surface area of ​​the dry composite is at least about 1.2 m 2 / g. In some embodiments, the dry composite has a D50 particle size of at least about 16 μm. In some embodiments, the silicon active material is selected from the group consisting of silicon, silicon derivatives, and combinations thereof. In some embodiments, the silicon derivative is silicon oxide (SiO x ), silicon carbide (SiC), silicon-carbon composite (Si / C), and combinations thereof. In some embodiments, the carbon active material comprises graphite, soft carbon, hard carbon, and combinations thereof. In some embodiments, the dry composite further comprises a composite binder. In some embodiments, the composite binder is selected from the group consisting of polyacrylic acid (PAA), cellulose, alginate (Alg), acrylate, acrylamide, polyacrylamide (PAM), gum, sulfonated tetrafluoroethylene-based fluoropolymer-copolymer, network polymer, acrylonitrile, amide-based binder, imide-based binder, amide-imide binder, polyvinylidene fluoride (PVDF), copolymers thereof, and combinations thereof. In some embodiments, the dry composite is substantially free of solvent residue.

[0009] In another aspect, an electrode film comprising a dry composite material is disclosed. In some embodiments, the electrode film further comprises a dry binder. In some embodiments, the dry binder is selected from the group consisting of polytetrafluoroethylene (PTFE), ultra-high molecular weight polyethylene (UHMWPE), polyvinylidene fluoride (PVDF), acrylate, acrylonitrile imide, amide, and combinations thereof. In some embodiments, the electrode film is self-supporting and substantially free of solvent residues.

[0010] In another aspect, an electrode is disclosed that includes an electrode film disposed on a current collector. In another aspect, an energy storage device is disclosed that includes the electrode. In some embodiments, the capacity of the electrode after 100 cycles is at least about 95% of the capacity of the electrode on the first cycle. In some embodiments, the capacity of the electrode is at least about 400 mAh / mg on the first cycle.

[0011] In another aspect, a method for preparing a dry composite material for an energy storage device electrode is disclosed. The method includes forming a mixture including a silicon active material, a carbon active material, and a carbon additive; and forming a dry composite including the silicon active material, the carbon active material, and the carbon additive, wherein the silicon active material and the carbon active material are substantially homogeneously dispersed in the dry composite.

[0012] In some embodiments, the mixture is a slurry and further comprises a solvent, and forming the dry composite further comprises removing the solvent. In some embodiments, the mixture further comprises a composite binder. In some embodiments, forming the dry composite is a process selected from the group consisting of spray drying, triple-kneader mixing, fluidized bed mixing, freeze-drying mixing, milling, mechanofusion, and combinations thereof.

[0013] In another aspect, a method for preparing a dry electrode film for an energy storage device electrode is disclosed. The method includes mixing a dry composite material with a dry binder to form a dry bulk mixture; and forming a free-standing dry electrode film from the dry electrode film mixture. In some embodiments, forming the free-standing dry electrode film is a dry process.

[0014] All of these embodiments are intended to be within the scope of the invention disclosed herein. These and other embodiments of the present 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, and the invention is not limited to any particular preferred embodiment disclosed. [Brief explanation of the drawings]

[0015] These and other features, aspects, and advantages of the present disclosure will be described with reference to the drawings of specific embodiments that are intended to illustrate particular embodiments and are not intended to limit the invention.

[0016] [Figure 1] FIG. 1 is a schematic diagram of an energy storage device comprising one or more electrode films.

[0017] [Figure 2] FIG. 1 is a diagram of a dry composite material, according to some embodiments.

[0018] [Figure 3] FIG. 1 is a process flow diagram of an embodiment of a process for forming a dry composite material.

[0019] [Figure 4A] 1 is a schematic diagram of an embodiment of an apparatus for fabricating dry composite materials.

[0020] [Figure 4B] FIG. 1 is a process flow diagram of an embodiment of a process for forming a dry composite material.

[0021] [Figure 5] FIG. 1 is a process flow diagram of an embodiment of a process for forming a dry electrode film.

[0022] [Figure 6] 1 shows a line graph of size distribution of a dry composite material according to some embodiments and a control material.

[0023] [Figure 7A] 1 is a scanning electron microscope (SEM) image of a surface of a dry-laid composite material according to some embodiments.

[0024] [Figure 7B] 7B is a scanning electron microscope (SEM) image of a surface of a dry composite material according to some embodiments, which is a more focused image of the SEM image of FIG. 7A.

[0025] [Figure 8] 1 shows bar and line graphs of capacity and first cycle efficiency (FCE) of half-cells fabricated with anodes including dry composite materials according to some embodiments and control anodes.

[0026] [Figure 9A] 1 shows bar and line graphs of capacity and first cycle efficiency (FCE) of full cells with anodes including dry composite materials according to some embodiments and control anodes.

[0027] [Figure 9B] 1 shows a line graph of capacity retention for full cells having an anode including a dry composite material according to some embodiments and a control anode. Detailed Description of the Invention

[0028] Provided herein are various embodiments of dry composite materials and electrode films for use in energy storage devices. In particular, in certain embodiments, the energy storage devices disclosed herein include an electrode film comprising a dry composite material including a silicon active material, a carbon active material, and a carbon additive (e.g., carbon nanotubes). When utilized in a dry electrode film manufacturing process, the dry composite material yielded an electrode film that was discovered to exhibit improved homogeneity, stability, and electrical properties. Methods for processing such dry composite materials and incorporating the dry composite material into an electrode film are also provided. The present disclosure reveals that when dry composite materials are fabricated and used in an electrode film, improved uniformity of material distribution in the electrode film can be achieved.

[0029] Dry electrode films fabricated using dry composite materials made from one or more processes described herein may demonstrate improved electrical properties, for example, due to improved and uniform distribution of one or more components of the electrode film. Disclosed herein are materials and methods that provide active materials with more uniform distribution and less agglomeration during fabrication. Certain embodiments of the energy storage devices provided herein may provide more uniform distribution of graphite and / or silicon active materials after processing. In particular, self-supporting and / or freestanding electrode films comprising such active materials are provided. One or more processes described herein may avoid agglomeration, insufficient distribution, phase separation, and wrapping failure of the active materials. In some embodiments, reducing or eliminating the use of high-shear devices and associated equipment such as air compressors and / or associated mixers may reduce manufacturing costs.

[0030] -Definition As used herein, the terms "battery" and "capacitor" should be given their ordinary and customary meaning to those of ordinary skill in the art. The terms "battery" and "capacitor" are mutually non-exclusive. A capacitor or battery may refer to a single electrochemical cell that may operate alone or as a component of a multi-cell system.

[0031] As used herein, the voltage of an energy storage device is the operating voltage of a single battery or capacitor cell. The voltage may be above the rated voltage or below the rated voltage under load or subject to manufacturing tolerances.

[0032] As provided herein, a "self-supporting" electrode film is an electrode film that incorporates a binder matrix structure sufficient to support the film or layer and maintain its shape so that the electrode film or layer is self-supporting. When incorporated into an energy storage device, a self-supporting electrode film or active layer is one that incorporates such a binder matrix structure. Generally, depending on the method used, such an electrode film or active layer is strong enough to be used in the energy storage device fabrication process without any external support elements, such as current collectors, support webs, or other structures, although support elements may be used to facilitate the energy storage device fabrication process. For example, a "self-supporting" electrode film may have sufficient strength to be rolled, handled, and unrolled within the electrode fabrication process without other support elements. A "free-standing" electrode film is a self-supporting electrode film without external support elements. A dry electrode film, such as a cathode electrode film or an anode electrode film, may be self-supporting.

[0033] As provided herein, a "solvent-free" electrode film is an electrode film that does not contain detectable process solvents, process solvent residues, or process solvent impurities. Process solvents or traditional solvents include organic solvents. Dry electrode films, such as cathode or anode electrode films, may be solvent-free.

[0034] A "wet" or "wet process" electrode is an electrode prepared by at least one process involving a slurry of active material, binder, and processing solvent, processing solvent residue, and / or processing solvent impurities. Wet electrodes may optionally contain additives. Wet process electrodes may still contain solvent, solvent residue, and / or solvent impurities even after a drying process is applied to the electrode film due to the solvent trapped within the volume of the electrode film and the limited temperature and / or drying time required to apply to the electrode to maintain performance.

[0035] As provided herein, a "dry" composite material is a composite material that does not contain, or is substantially free of, or contains detectable amounts of processing solvent, processing solvent residue, and / or processing solvent impurities. A composite material produced from a process that may include a solvent (e.g., a slurry of material) may be a "dry" composite material, for example, via a manufacturing process and / or additional dry processing steps that sufficiently evaporate the solvent, solvent residue, and solvent impurities.

[0036] -Energy storage devices FIG. 1 shows a side cross-sectional schematic diagram of an example energy storage device 100. The energy storage device 100 can be any number of energy storage devices, such as a lithium ion capacitor, a lithium ion battery, an electric double layer energy storage device, or the like. Of course, other energy storage devices are within the scope of the present invention, and the device 100 can be other types of energy storage devices, such as a capacitor, a capacitor-battery hybrid, or a fuel cell. The energy storage device 100 can have a first electrode 102, a second electrode 104, and a separator 106 positioned between the first electrode 102 and the second electrode 104. For example, the first electrode 102 and the second electrode 104 can be disposed adjacent opposite sides of the separator 106. The first electrode 102 can comprise a cathode, and the second electrode 104 can comprise an anode, or vice versa. The energy storage device 100 can include an electrolyte to facilitate ionic communication between the electrodes 102, 104 of the energy storage device 100. For example, the electrolyte may be in contact with the first electrode 102, the second electrode 104, and the separator 106. The electrolyte, the first electrode 102, the second electrode 104, and the separator 106 may be contained within the energy storage device housing 120. For example, the energy storage device housing 120 may be sealed following insertion of the first electrode 102, the second electrode 104, and the separator 106 and impregnation of the energy storage device 100 with the electrolyte, such that the first electrode 102, the second electrode 104, the separator 106, and the electrolyte may be physically sealed from the environment external to the housing.

[0037] The separator 106 may be configured to electrically insulate two adjacent electrodes, such as the first electrode 102 and the second electrode 104, on opposite sides of the separator 106 and allow ionic communication between the two adjacent electrodes. The separator 106 may include various porous or nonwoven electrically insulating materials. In some embodiments, the separator 106 may include a polymeric material. The separator 106 may include a composite of a polymeric material. The separator 106 may include a composite of one or more polymeric materials with a ceramic and / or a metal oxide. The ceramic or metal oxide may be a powder. For example, the separator 106 may include a cellulose material such as paper. The separator 106 may include a porous or nonwoven polyethylene (PE) material. The separator 106 may include a polytetrafluoroethylene material, such as a porous polytetrafluoroethylene material. The separator 106 may include a polypropylene (PP) material, such as a porous or nonwoven polypropylene (PP) material. Separator 106 may, for example, comprise a polyethylene coating on a porous or non-woven polypropylene material or a composite of polymeric materials.

[0038] As shown in FIG. 1 , the first electrode 102 and the second electrode 104 may include a first current collector 108 and a second current collector 110, respectively. The first current collector 108 and the second current collector 110 may facilitate electrical connection between the corresponding electrode and an external circuit (not shown). The first current collector 108 and the second current collector 110 may comprise one or more conductive materials. The first current collector 108 and the second current collector 110 may have various shapes and / or sizes. The first current collector 108 and the second current collector 110 may be configured to facilitate the transfer of charge between the corresponding electrode and the external circuit. For example, the first current collector 108 may be electrically connected to a first energy storage device terminal 122, such as an electrically positive terminal, via a first connection 126. The second current collector 110 may be electrically connected to a second energy storage device terminal 124, such as an electrically negative terminal, via a second connection 128. The first and second energy storage device terminals 122, 124 may be electrically connected to respective terminals of an external circuit to connect the energy storage device 100 to the external circuit.

[0039] The current collectors may comprise metallic materials, such as materials containing aluminum, nickel, copper, silver, alloys thereof, and / or other metallic materials, or non-metallic materials, such as graphite, that remain inert at the device's electrode potential. In some embodiments, the current collectors further comprise a coating layer. In some embodiments, the coating layer comprises a carbon coating. The first current collector 108 and / or the second current collector 110 may comprise foil. The first current collector 108 and the second current collector 110 may have a rectangular or generally rectangular shape and may be sized to provide the desired transfer of charge between the corresponding electrode and an external electrical circuit. The energy storage device 100 may include any of several different configurations for providing this electrical communication between the electrodes 102, 104 and the external electrical circuit via the current collectors 108, 110, respectively. For example, this transfer may be provided via a current collector plate and / or another energy storage device component.

[0040] The first electrode 102 may have a first electrode film 112 (e.g., a top electrode film) on a first surface of the first current collector 108 (e.g., a top surface of the first current collector 108). The first electrode 102 may have a second electrode film 114 (e.g., a bottom electrode film) on a second, opposing surface of the first current collector 108 (e.g., on a bottom surface of the first current collector 108). Similarly, the second electrode 104 may have a first electrode film 116 (e.g., a top electrode film) on a first surface of the second current collector 110 (e.g., a top surface of the second current collector 110). The second electrode 104 may have a second electrode film 118 on a second, opposing surface of the second current collector 110 (e.g., on a bottom surface of the second current collector 110). For example, a first surface of the second current collector 110 may face a second surface of the first current collector 108 such that the separator 106 is adjacent to the second electrode film 114 of the first electrode 102 and the first electrode film 116 of the second electrode 104.

[0041] The electrode films 112, 114, 116, and / or 118 can have a variety of suitable shapes, sizes, and / or thicknesses. For example, the electrode films can have a thickness of about 30 microns (μm) to about 2000 microns, such as about 100 microns to about 250 microns, or even about 30 microns to about 250 microns. The electrode films 112, 114, 116, and / or 118 can have the same or different thicknesses, compositions, and densities relative to one another. For example, the electrode films 112 and 114 can have different thicknesses, compositions, or densities compared to the electrode films 116 and 118.

[0042] In some embodiments, an anode and / or cathode electrode film of an energy storage device comprises a dry binder material, one or more active electrode components, and / or one or more conductivity-promoting additives. In some embodiments, the one or more active electrode components and the one or more conductivity-promoting additives together form a dry composite material as described herein, such that the electrode film comprises a dry binder material and a dry composite material.

[0043] In some embodiments, the anode and / or cathode electrode films may include one or more dry binder materials. In some embodiments, the dry binder may include polytetrafluoroethylene (PTFE), polyolefin, polyalkylene, polyether, styrene-butadiene, polysiloxane copolymers and polysiloxanes, branched polyethers, polyvinyl ethers, copolymers thereof, and / or mixtures thereof. The binder may include cellulose, such as carboxymethyl cellulose (CMC). In some embodiments, the polyolefin may include polyethylene (PE), polypropylene (PP), polyvinylidene fluoride (PVDF), copolymers thereof, and / or mixtures thereof. For example, the binder may include polyvinylene chloride, poly(phenylene oxide) (PPO), polyethylene-block-poly(ethylene glycol), poly(ethylene oxide) (PEO), poly(phenylene oxide) (PPO), polyethylene-block-poly(ethylene glycol), polydimethylsiloxane (PDMS), polydimethylsiloxane-coalkylmethylsiloxane, copolymers thereof, and / or mixtures thereof. In some embodiments, the dry binder may be a thermoplastic. In some embodiments, the dry binder includes a fibrous polymer. In some embodiments, the dry binder material may include one or more of a variety of suitable polymeric materials, such as polytetrafluoroethylene (PTFE), ultra-high molecular weight polyethylene (UHMWPE), polyvinylidene fluoride (PVDF), acrylates (e.g., melt-processable acrylates), acrylonitrile imides, amides, binders provided herein, and / or other suitable, optionally fibrous materials, used alone or in combination. In some embodiments, the electrode film may include a polymer, such as a polymeric binder material, and one or more other components. Polymer is a general term and can include homopolymers, copolymers, and mixtures of polymers provided herein. In some embodiments, the polymer can be a dry binder material.In some embodiments, the electrode film may include 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, 5 wt%, 5.5 wt%, 6 wt%, 6.5 wt%, 7 wt%, 7.5 wt%, 8 wt%, 8.5 wt%, 8.5 wt%, 9 wt%, 9.5 wt%, or 10 wt% of dry binder, or any range of values ​​therebetween, or about that amount, for example, from about 1 wt% to about 10 wt%, where wt% is based on the weight of the electrode film.

[0044] In some embodiments, the anode and / or cathode electrode films may include one or more active electrode components. In some embodiments, the active electrode components may be selected from silicon active materials, carbon active materials, and combinations thereof. In some embodiments, the silicon active material may be silicon (e.g., metallurgical silicon (MG Si)), silicon oxide (SiO x), silicon-carbon composites (Si-C or Si / C), silicon carbide (SiC), or combinations thereof. In some embodiments, the active electrode component may include a carbon active material. In some embodiments, the carbon active material may include a carbonaceous material. In some embodiments, the carbonaceous material may include soft carbon, hard carbon, graphite (e.g., natural graphite and artificial graphite), and combinations thereof. In some embodiments, one or more active electrode components may include a porous carbon material, such as activated carbon. In some embodiments, one or more active electrode components may include a carbon active material, such as graphite, soft carbon, and / or hard carbon, configured to reversibly intercalate lithium ions. In some embodiments, the electrode film and / or active electrode component may include an additional active electrode material. In some embodiments, the additional active electrode material may be selected from an intercalation material (e.g., carbon and / or graphene), an alloying / dealloying material (e.g., oxide, tin, and / or tin oxide), a metal alloy or compound (e.g., Si—Al and / or Si—Sn), and / or a conversion material (e.g., manganese oxide, molybdenum oxide, nickel oxide, and / or copper oxide). The additional active materials may be used alone or mixed together to form a multiphase material (e.g., Sn—C, SiOx—C, SnOx—C, Si—Sn, Si—SiOx, Sn—SnOx, Si—SiOx—C, Sn—SnOx—C, Si—Sn—C, SiOx—SnOx—C, Si—SiOx—Sn, or Sn—SiOx—SnOx). In some embodiments, the active electrode component may include a lithium metal oxide. In some embodiments, the active electrode components may incorporate a lithium ion-rich source for the purpose of prelithiating the anode and advantageously reducing or eliminating first cycle inefficiencies.In some embodiments, the electrode film may comprise 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt%, 80 wt%, 82 wt%, 84 wt%, 85 wt%, 87 wt%, 89 wt%, 90 wt%, 92 wt%, 95 wt%, 97 wt%, 99 wt%, or 99.5 wt%, or any range of values ​​therebetween, such as about 40 wt% to about 99.5 wt%, where wt% is based on the weight of the electrode film. In some embodiments, the electrode film may comprise about 1 wt% to about 10 wt% active silicon material and about 40 wt% to about 99.5 wt% carbon active material.

[0045] In some embodiments, the anode and / or cathode electrode films may include one or more additives, including electrical or ionic conductivity-promoting additives. In some embodiments, the conductivity-promoting additive may be a carbon additive. In some embodiments, the carbon additive may include carbon nanotubes (CNTs), carbon black, carbon nanofibers (CNFs), and combinations thereof. In some embodiments, the CNTs may include single-walled carbon nanotubes (SWCNTs), double-walled carbon nanotubes (DWCNTs), double-walled carbon nanotubes (FWCNTs), multi-walled carbon nanotubes (MWCNTs), and combinations thereof. In some embodiments, the carbon black may include conductive carbon black. In some embodiments, the carbon black may include acetylene black (AB), super P conductive carbon black, Ketjenblack (KB) carbon black, and combinations thereof. In some embodiments, the electrode film may include the carbon additive at or about 0.05 wt%, 0.1 wt%, 0.2 wt%, 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, or any range therebetween, for example, from about 0.05 wt% to about 4 wt%, where wt% is based on the weight of the electrode film.

[0046] In some embodiments, the electrode film may include the dry composite at or about 80 wt%, 82 wt%, 84 wt%, 86 wt%, 88 wt%, 90 wt%, 91 wt%, 92 wt%, 93 wt%, 94 wt%, 95 wt%, 96 wt%, 97 wt%, 98 wt%, 99 wt%, 99.5 wt%, or any range therebetween, for example, about 90 wt% to about 99.5 wt%, about 95 wt% to about 99.5 wt%, or about 97 wt% to about 98 wt%, where wt% is based on the weight of the electrode film.

[0047] In some embodiments, the electrode film, which is a dry and / or self-supporting film, has a coating density of 10 mg / cm 2 , about 11mg / cm 2 , about 12mg / cm 2 , about 13mg / cm 2 , about 14mg / cm 2 , about 15mg / cm 2 , about 16mg / cm 2 , about 17mg / cm 2 , about 18mg / cm 2 , about 19mg / cm 2 , about 20mg / cm 2 , about 21mg / cm 2 , about 22mg / cm 2 , about 23mg / cm 2 , about 24mg / cm 2 , about 25mg / cm 2 , about 26mg / cm 2 , about 27mg / cm 2 , about 28mg / cm 2 , about 29mg / cm 2 , about 30mg / cm 2 , about 40mg / cm 2 , about 50mg / cm 2 , or any range of values ​​therebetween, or about that value, e.g., about 10 mg / cm 2 ~about 50mg / cm 2 high electrode material loading, or high active material loading (which can be expressed as the mass of electrode film per unit area of ​​electrode film or current collector).

[0048] In some embodiments, the electrode film has a coating thickness of 0.8 g / cm 3 , 1.0g / cm 3 , 1.4g / cm 3 , about 1.45g / cm 3 , about 1.5g / cm 3 , about 1.6g / cm 3 , about 1.7g / cm 3 , about 1.8g / cm 3 , about 1.9g / cm 3 , about 2.0g / cm 3 , about 2.5g / cm 3 , about 3.0g / cm 3 , about 3.3g / cm 3 , approximately 3.4 g / cm 3 , about 3.5g / cm 3 , about 3.6g / cm 3 , about 3.7g / cm 3 or approximately 3.8 g / cm 3 , or any range of values ​​therebetween, or about that value, for example, about 0.8 g / cm 3 ~Approx. 3.8g / cm 3 The electrode film density may be

[0049] -Dry composite materials The dry composite material may include a carbon additive and an active material. In some embodiments, the carbon additive may include carbon nanotubes (CNTs), carbon black, carbon nanofibers (CNFs), and combinations thereof. In some embodiments, the CNTs may include single-walled carbon nanotubes (SWCNTs), double-walled carbon nanotubes (DWCNTs), double-walled carbon nanotubes (FWCNTs), multi-walled carbon nanotubes (MWCNTs), and combinations thereof. In some embodiments, the carbon black may include conductive carbon black. In some embodiments, the carbon black may include acetylene black (AB), super P conductive carbon black, Ketjen Black (KB) carbon black, and combinations thereof. In some embodiments, the elements of the dry composite material (e.g., the active material and the carbon additive) are substantially homogeneously dispersed. In some embodiments, the elements of the dry composite material (e.g., the active material and the carbon additive) do not substantially aggregate or agglomerate. 2 is an exemplary diagram of a dry composite material, which may include Si / C as a silicon active material, graphite as a carbon active material, a polymer composite binder, and CNTs homogeneously dispersed therein. In some embodiments, the carbon nanotubes are single-walled carbon nanotubes (SWCNTs).

[0050] In some embodiments, the active material may be selected from silicon active materials, carbon active materials, and combinations thereof. In some embodiments, the silicon active material may be silicon (e.g., metallurgical silicon (MG Si)), silicon oxide (SiO x), silicon-carbon composites (Si-C or Si / C), silicon carbide (SiC), or combinations thereof. In some embodiments, the silicon carbide may include layered silicon carbide. In some embodiments, the carbon active material may include a carbonaceous material. In some embodiments, the carbonaceous material may include soft carbon, hard carbon, graphite (e.g., natural graphite and artificial graphite), and combinations thereof. In some embodiments, one or more active electrode components include a porous carbon material, such as activated carbon. In some embodiments, one or more active electrode components include a carbon material, such as graphite, soft carbon, and / or hard carbon, configured to reversibly intercalate lithium ions.

[0051] In some embodiments, the dry composite material may include an additional active electrode material. In some embodiments, the additional active electrode material may be selected from an intercalation material (e.g., carbon and / or graphene), an alloying / dealloying material (e.g., oxide, tin, and / or tin oxide), a metal alloy or compound (e.g., Si—Al and / or Si—Sn), and / or a conversion material (e.g., manganese oxide, molybdenum oxide, nickel oxide, and / or copper oxide). The additional active materials may be used alone or mixed together to form a multiphase material (e.g., Sn—C, SiOx—C, SnOx—C, Si—Sn, Si—SiOx, Sn—SnOx, Si—SiOx—C, Sn—SnOx—C, Si—Sn—C, SiOx—SnOx—C, Si—SiOx—Sn, or Sn—SiOx—SnOx).

[0052] In some embodiments, the dry composite material may further include a composite binder. In some embodiments, the composite binder may include a polymer binder. In some embodiments, the composite binder may include a water-based binder, an organic solvent-based binder, and combinations thereof. In some embodiments, the composite binder may be selected from polyacrylic acid (PAA), cellulose (e.g., carboxymethylcellulose (CMC), alginates (Alg) (e.g., sodium alginate (Na-Alg)), acrylates (e.g., poly(methyl methacrylate) (PMMA), Li-PMMA), acrylamide, polyacrylamide (PAM), gums (e.g., gum arabic, guar gum, chitosan, dextran), sulfonated tetrafluoroethylene-based fluoropolymer-copolymers (e.g., Nafion), network polymers (e.g., interpenetrating polymer networks (IPN)), acrylonitrile (e.g., water-based acrylonitrile (e.g., acrylonitrile multicopolymer binder (LA-133))), amide-based binders, imide-based binders, amide-imide binders, polyvinylidene fluoride (PVDF), copolymers thereof (e.g., PAA-PVA, PAA-CMC), and combinations thereof.

[0053] In some embodiments, the dry composite can include impurities. In some embodiments, the impurities include Al, Cr, Fe, Li, Mg, Mn, Na, Ni, S, Zn, and combinations thereof. In some embodiments, the dry composite can include impurities in an amount at, about, or less than 10,000 ppm, 8,000 ppm, 5,000 ppm, 3,000 ppm, 2,000 ppm, 1,000 ppm, 800 ppm, 700 ppm, 500 ppm, 100 ppm, 50 ppm, or any range therebetween, for example, from about 50 ppm to about 10,000 ppm.

[0054] In some embodiments, the dry composite may include particles. In some embodiments, the particles may be solvent-free dry particles. In some embodiments, the dry composite may have a median particle size (D50) of 10 μm, 11 μm, 12 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, or 30 μm, or any range of values ​​therebetween, or about that value, for example, about 10 μm to about 30 μm. In some embodiments, the dry composite may have a median particle size (D50) of 1 μm, 11 μm, 12 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, or 30 μm, or any range of values ​​therebetween, or about that value, for example, about 10 μm to about 30 μm. 2 / g, 1.1m 2 / g, 1.2m 2 / g, 1.3m 2 / g, 1.4m 2 / g, 1.5m 2 / g, 1.6m 2 / g, 1.7m 2 / g, 1.8m 2 / g, 1.9m 2 / g, 2m 2 / g, or any range of values ​​therebetween, or about that value, e.g., about 1 m 2 / g ~ approx. 2m 2 / g specific surface area.

[0055] In some embodiments, an advantage of the present application is that the carbon additive, silicon active material, and / or carbon active material are homogeneously or substantially homogeneously dispersed throughout the dry composite. In some embodiments, the substantially homogeneous or homogeneous dispersion may be indicated by reduced or substantially reduced agglomeration and / or phase separation of the active material and / or carbon additive in the dry composite and in dry electrode films fabricated using the dry composite compared to electrode films fabricated without the dry composite. For example, in some embodiments, the median particle size (D50) of the dry composite may be, about, up to, or about 300%, 275%, 250%, 225%, 200%, 175%, 150%, 140%, 130%, 120%, 110%, 100%, 90%, or 80% of the median particle size (D50) of the silicon active material and / or the carbon active material, or any range therebetween. In another example, in some embodiments, the specific surface area of ​​the dry composite may be, about, up to, or about 50%, 60%, 70%, 80%, 90%, 100%, 110%, 120%, 130%, 140%, or 150% of the specific surface area of ​​the carbon active material and / or the silicon active material, or any range therebetween. In additional examples, in some embodiments, the aggregation of particles in the dry electrode film may be, about, up to, or about 15x, 10x, 9x, 8x, 7x, 6x, 5x, 4x, 3x, 2x, or 1.5x the size of the carbon and / or silicon active material, or any range therebetween.

[0056] In some embodiments, the dry composite may include the carbon additive at or about 0.01 wt%, 0.05 wt%, 0.1 wt%, 0.15 wt%, 0.20 wt%, 0.25 wt%, 0.3 wt%, 0.35 wt%, 0.40 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, or 1.0 wt%, or any range of values ​​therebetween, for example, about 0.01 wt% to about 1 wt%, where wt% is based on the weight of the dry composite. In some embodiments, the dry composite may include about 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, or any range of values ​​therebetween, e.g., about 2 wt% to 10 wt%, where wt% is based on the weight of the dry composite. In some embodiments, the dry composite may include about 55 wt%, 80 wt%, 85 wt%, 90 wt%, 93 wt%, 94 wt%, 94.5 wt%, 95 wt%, 96 wt%, 97 wt%, 98 wt%, 99 wt%, or any range of values ​​therebetween, e.g., about 75 wt% to 99 wt%, where wt% is based on the weight of the dry composite. Method for fabricating dry composite materials

[0057] A dry composite may be produced and then utilized to fabricate an electrode film. In some embodiments, the dry composite may be formed by a slurry process and / or a solventless process.

[0058] FIG. 3 is a process flow diagram of an embodiment of a process 300 for forming a dry composite material. The method for forming the dry composite material 300 may include, in step 302, forming a mixture including a carbon additive and an active material. In some embodiments, the active material may be or include any active material (e.g., active electrode component) described herein. For example, in some embodiments, the active material may include a carbon active material, a silicon active material, or a combination thereof. In some embodiments, the active material may be selected from the group consisting of a carbon active material, a silicon active material, or a combination thereof. In some embodiments, the silicon active material may be silicon (e.g., metallurgical silicon (MG Si)), silicon oxide (SiO x), silicon-carbon composites (Si-C or Si / C), silicon carbide (SiC), or combinations thereof. In some embodiments, the carbon additive may include soft carbon, hard carbon, graphite (e.g., natural graphite and artificial graphite), and combinations thereof. In some embodiments, the carbon additive may include carbon nanotubes (CNTs), carbon black, carbon nanofibers (CNFs), and combinations thereof. In some embodiments, the mixture may contain additional elements of a dry composite, such as a composite binder. In some embodiments, the mixture may be a slurry and may further include a liquid, such as in a spray-drying process. A dry composite may be formed from the mixture in step 304. In some embodiments, the dry composite may be formed by a process selected from spray drying, triple-kneader mixing, fluidized-bed mixing, freeze-drying mixing, milling, mechanofusion, and combinations thereof. In some embodiments, the dry composite may be formed by removing liquid and / or solvent from the mixture, such as in a spray-drying process. In some embodiments, the dry composite may be substantially free of solvents or liquids. In some embodiments, the dry composite may maintain a substantially homogeneous distribution of components (e.g., carbon additive, active material, and / or composite binder) throughout the dry composite. In some embodiments, the resulting yield of the process for forming the dry composite may be or be about 40 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 80 wt%, or 90 wt%, or any range therebetween, for example, about 40 wt% to about 90 wt%, where wt% is based on the weight of the mixture.

[0059] 4A and 4B schematically illustrate a spray-drying apparatus and a method of using such a spray-drying apparatus to form a dry composite material according to some embodiments. As shown in FIGS. 4A and 4B, in step 420, a slurry can be formed in a vessel 402. In some embodiments, the slurry can be formed by mixing a solution of a carbon additive material and one or more active materials with a liquid. In some embodiments, a composite binder can be added to the mixture to form the slurry. In some embodiments, the active material can include a carbon active material, a silicon active material, or a combination thereof. In some embodiments, the active material can be a Si / C composite and graphite. In some embodiments, the carbon additive can include carbon nanotubes (CNTs), carbon black, carbon nanofibers (CNFs), and combinations thereof. In some embodiments, the carbon additive can be carbon nanotubes. In some embodiments, the slurry can be formed by mixing the components with a mixer. In some embodiments, the slurry can be further diluted to achieve a desired weight percentage solids. In step 422, the slurry can be spray-dried by passing through a spray nozzle 404 and entering a drying chamber 406. After the slurry is spray dried in chamber 406 in step 422, a dried composite material may be formed in step 424 and transported to cyclone 408 and then collected in powder collector 412. Dust collector 410 may be configured to collect any dust from the slurry that does not form a dried composite.

[0060] In some embodiments, the slurry can be formed by mixing the components of the dry composite material (e.g., carbon additive and active material; carbon additive, active material and composite binder; or carbon additive, carbon active material, silicon active material and composite binder) with a liquid. In some embodiments, the liquid can include an aqueous solvent and / or an organic solvent. In some embodiments, the liquid can include water. In some embodiments, the components of the mixture (e.g., carbon additive, active material, binder, and liquid) can be substantially homogeneously mixed and / or distributed in the slurry mixture. In some embodiments, the slurry can be formed by mixing a solution including the carbon additive and composite binder with the carbon active material and silicon active material. In some embodiments, the solution may comprise 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1.0 wt%, 1.1 wt%, 1.2 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, or 4 wt%, or any range of values ​​therebetween, or about that value, for example, from about 0.1 wt% to about 4 wt%, of carbon additive, where wt% is based on the weight of the solution. In some embodiments, the solution may contain 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, 4.9 wt%, 5 wt%, 5.5 wt%, 6 wt%, 6.5 wt%, 7 wt%, 7.5 wt%, 8 wt%, 8.5 wt%, 9 wt%, 9.5 wt%, or 10 wt%, or any range of values ​​therebetween, or about that value, e.g., about 0.5 wt% to about 10 wt%, of the composite binder, where wt% is based on the weight of the dry composite material. In some embodiments, a slurry may be formed by mixing the solution (e.g., the solution may include a carbon additive, a composite binder, a carbon active material, and a silicon active material) for a period of time using a mixer. In some embodiments, the mixing time may be or may be about 200 seconds, 250 seconds, 300 seconds, 350 seconds, 365 seconds, 400 seconds, 450 seconds, 500 seconds, 550 seconds, or 600 seconds, or any range of values ​​therebetween, for example, from about 200 seconds to about 600 seconds.In some embodiments, mixing may be performed two or more times, such as two, three, four, five, six, or any number of times required. In some embodiments, the mixer speed may be at or about 500 rpm, 600 rpm, 700 rpm, 750 rpm, 800 rpm, 850 rpm, 900 rpm, 1000 rpm, 1100 rpm, 1200 rpm, 1300 rpm, 1400 rpm, or 1500 rpm, or any range therebetween, for example, from about 500 rpm to about 1500 rpm.

[0061] In some embodiments, after the slurry is formed, the slurry may be further diluted. In some embodiments, diluting the slurry may include diluting the slurry to achieve a solids content of 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, or 60 wt%, or any range of values ​​therebetween, or about that value, e.g., about 20 wt% to about 60 wt%, where wt% is based on the weight of the slurry. In some embodiments, diluting the slurry may include diluting the slurry to achieve a viscosity of 500 cp, 450 cp, 400 cp, 350 cp, 300 cp, 250 cp, 200 cp, 150 cp, or 100 cp, or any range of values ​​therebetween, about that value, less than that value, or about less than that value, e.g., about 100 cp to about 500 cp. In some embodiments, dilution may be achieved using a mixer (e.g., an overhead mixer).

[0062] In some embodiments, when a slurry mixture of the components is used, the method for removing the solvent from the slurry may be spray drying. In some embodiments, the airflow rate for the spray drying may be about or at 50 cpm, 55 cpm, 60 cpm, 65 cpm, 70 cpm, 75 cpm, 80 cpm, 85 cpm, 90 cpm, 95 cpm, or 100 cpm, or any range of values ​​therebetween, e.g., about 50 cpm to about 100 cpm. In some embodiments, the inlet temperature for the spray drying may be about or at 150°C, 170°C, 190°C, 200°C, 210°C, 230°C, 250°C, 270°C, 290°C, or 300°C, or any range of values ​​therebetween, e.g., about 150°C to about 300°C. In some embodiments, the product temperature for spray drying can be about or at 80° C., 90° C., 100° C., 110° C., 130° C., 150° C., 170° C., 190° C., or 200° C., or any range therebetween, for example, from about 80° C. to about 200° C. In some embodiments, the spray drying throughput can be about or at 20 g / min, 30 g / min, 45 g / min, 50 g / min, 60 g / min, 70 g / min, or 80 g / min, or any range therebetween, for example, from about 20 g / min to 80 g / min.

[0063] -Method of using dry composite materials in the manufacture of electrode films and energy storage devices The dry composite material can be used to form an electrode film. Electrode films including the dry composite material can be used to form electrodes and energy storage devices, such as those described herein. Advantageously, the dry electrode films disclosed herein can include a conductive carbon network across the dry electrode film in contact with the carbon and / or silicon active material. In addition, active material aggregation and phase separation can be significantly reduced compared to dry electrode films fabricated using raw materials instead of dry composite materials. Therefore, the cycle life performance and capacity of energy storage devices fabricated using dry electrode films according to some embodiments can be improved, and the expected capacity can be fully utilized.

[0064] After forming the dry composite, the dry composite can be used to form a dry electrode film. In some embodiments, the dry electrode film including the dry composite can be manufactured by a dry or wet fabrication process. As used herein, a dry fabrication process or dry process can refer to a process in which no, or substantially no, solvent is used to form the electrode film.

[0065] 5 is a process flow diagram of an embodiment of a process 500 for forming a dry electrode film. As shown in FIG. 5, in step 502, a dry electrode film mixture including a dry composite material and a dry binder may be mixed. In step 504, a free-standing dry electrode film may be formed from the electrode film mixture. In some embodiments, the dry electrode film may be formed by a dry fabrication process.

[0066] In some embodiments, the components of the active layer or electrode film may include dry particles, such as a dry composite. The dry particles for forming the active layer or electrode film may be combined with a dry binder to provide an electrode film mixture. In some embodiments, the active layer or electrode film may be formed from an electrode film mixture such that the weight percentages of the components of the active layer or electrode film and the weight percentages of the components of the electrode film mixture are substantially the same. In some embodiments, an active layer or electrode film formed from an electrode film mixture using a dry fabrication process may be free or substantially free of any processing additives, such as solvents and solvent residues resulting therefrom. In some embodiments, the resulting active layer or electrode film is a self-supporting film formed using a dry process from a dry particle mixture. In some embodiments, the resulting active layer or electrode film is a free-standing film formed using a dry process from an electrode film mixture. The process for forming the active layer or electrode film may include fiberizing a fibrous binder component such that the film may include a fiberized binder. In further embodiments, the free-standing active layer or electrode film may be formed in the absence of a current collector. In yet further embodiments, the active layer or electrode film may include a fiberized polymer matrix such that the film is self-supporting. It is believed that a matrix, lattice, or web of fibrils may be formed to provide mechanical structure to the electrode film.

[0067] In some embodiments, the electrode film mixture may include 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, 5 wt%, 5.5 wt%, 6 wt%, 6.5 wt%, 7 wt%, 7.5 wt%, 8 wt%, 8.5 wt%, 8.5 wt%, 9 wt%, 9.5 wt%, or 10 wt%, or any range of values ​​therebetween, or at about that amount, for example, from about 1 wt% to about 10 wt%, where wt% is based on the weight of the electrode film mixture.

[0068] In some embodiments, the dry binder may include a polymer binder. In some embodiments, the dry binder may include polytetrafluoroethylene (PTFE), polyolefin, polyalkylene, polyether, styrene-butadiene, copolymers of polysiloxane and polysiloxane, branched polyether, polyvinyl ether, copolymers thereof, and / or mixtures thereof. The binder may include cellulose, such as carboxymethyl cellulose (CMC). In some embodiments, the polyolefin may include polyethylene (PE), polypropylene (PP), polyvinylidene fluoride (PVDF), copolymers thereof, and / or mixtures thereof. For example, the binder may include polyvinylene chloride, poly(phenylene oxide) (PPO), polyethylene-block-poly(ethylene glycol), poly(ethylene oxide) (PEO), poly(phenylene oxide) (PPO), polyethylene-block-poly(ethylene glycol), polydimethylsiloxane (PDMS), polydimethylsiloxane-coalkylmethylsiloxane, copolymers thereof, and / or mixtures thereof. In some embodiments, the binder may be a thermoplastic, hi some embodiments, the dry binder may include a fibrous polymer.

[0069] In some embodiments, the size of the components and / or particles of the electrode film mixture can be reduced by using high-shear equipment and processes, such as jet milling. High shear forces can be applied to separate binder material aggregates into finely divided particles and / or fiberize the binder material so that it can coat other electrode film components. In some embodiments, the resulting dried powder can be compressed under heat and pressure using a roll mill to form a film, for example, by PTFE calling and bonding with other components of the film in the fiberized matrix. The thickness of the film can depend on the roll gap of the roll mill, the pressure applied during the compression process, and / or the number of times the film is compressed. The dry fabrication process can result in a fiberized matrix such that the electrode film is self-supporting and / or freestanding.

[0070] In some embodiments, one or more electrode film mixtures described herein can be combined with one or more other electrode film components and subsequently calendered to form an electrode film. The electrode film can be one or more of the electrode films described with reference to FIG. 1. The electrode films described herein can be used to form the anode and / or cathode of an energy storage device, such as, for example, a capacitor, a capacitor-battery hybrid, a fuel cell, or a combination thereof. The energy storage device can operate with or without lithium. In some embodiments, the electrode film can be used to fabricate a battery, such as a lithium-ion battery or other metal-ion battery. In some embodiments, the electrode film can be used to fabricate an ultracapacitor, such as an electric double-layer capacitor (EDLC). In some embodiments, the electrode film can be used to fabricate a lithium-ion capacitor. The electrode film can be a self-supporting electrode film provided herein.

[0071] In some embodiments, dry electrode films formed from the electrode film blends provided herein may be suitable for use in the anode or cathode of an energy storage device. For example, the dry electrode film may be connected to an anode or cathode current collector to form a dry electrode, such as by using a lamination process. In some embodiments, the dry electrode film may be laminated onto a current collector. In some embodiments, the lamination is performed at elevated temperatures (e.g., 50-100°C).

[0072] In some embodiments, dry electrodes according to some embodiments may be utilized in half cells. In some embodiments, half cells may be formed by using the dry electrodes disclosed herein with metal electrodes as counter and reference electrodes. In some embodiments, the metal electrodes may be lithium metal electrodes. In some embodiments, the half cells may further include an electrolyte between the dry electrode and the metal electrode, the electrolyte including metal ions of the metal electrode. In some embodiments, the capacity of the dry electrodes according to some embodiments fully achieves the predicted capacity calculated based on the volume and weight of the active materials in the half cell. In some embodiments, the discharge capacity of a dry electrode according to some embodiments in a half cell can be about or equal to 300 mAh / g, 350 mAh / g, 400 mAh / g, 410 mAh / g, 420 mAh / g, 450 mAh / g, 500 mAh / g, 550 mAh / g, 600 mAh / g, 650 mAh / g, 700 mAh / g, 750 mAh / g, 800 mAh / g, 850 mAh / g, 900 mAh / g, 950 mAh / g, or 1000 mAh / g, or any range therebetween, for example, from about 300 mAh / g to about 1000 mAh / g. In some embodiments, the first cycle efficiency (FCE) of a half-cell according to some embodiments may be about, at least, or at least about 80%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 95%, 96%, 97%, 98%, or 99%, or any range therebetween.

[0073] In some embodiments, electrodes formed herein may be incorporated into an energy storage device, such as a full-cell lithium-ion battery, as shown in FIG. 1. In some embodiments, the electrode film disclosed herein may be an anode. In some embodiments, an electrode according to some embodiments may be disposed within the energy storage device and sealed with a housing. In some embodiments, an electrolyte may be added within the energy storage device and sealed with a housing. In some embodiments, the electrolyte may be a lithium-containing electrolyte including a lithium salt. Generally, the lithium salt may include an anion that is redox-stable. In some embodiments, the anion may be monovalent. In some embodiments, the lithium salt may 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 may comprise a quaternary ammonium cation and an anion selected from the group consisting of hexafluorophosphate, tetrafluoroborate, and iodide. In some embodiments, the salt concentration is at or about 0.2 M, 0.3 M, 0.4 M, 0.5 M, 0.6 M, 0.7 M, 0.8 M, 0.9 M, 1 M, 1.1 M, or 1.2 M, or any range of values ​​therebetween.

[0074] In some embodiments, the capacity of a lithium ion battery with dry electrodes may be configured to maintain a capacity of about, at least, or at least about 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99%, or any range of values ​​therebetween, of the first cycle or first cycle capacity thereafter for 100, 200, 500, or 1000 cycles, or any range of values ​​therebetween. In some embodiments, the initial discharge capacity of a dry electrode according to some embodiments in a full cell is or is about 100 mAh / g, 150 mAh / g, 200 mAh / g, 250 mAh / g, 300 mAh / g, 400 mAh / g, 450 mAh / g, 500 mAh / g, 550 mAh / g, or 600 mAh / g, or any range therebetween, for example, from about 100 to about 600 mAh / g. In some embodiments, the first cycle efficiency (FCE) of a dry electrode according to some embodiments in a full cell is, is about, is at least, or is at least about 80%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 95%, 96%, 97%, 98%, or 99%, or any range therebetween, for example, from about 80% to about 99%.

[0075] In some embodiments, the energy storage device (e.g., a lithium ion battery) is configured to operate between 2.5 V and 4.5 V, or between 2.8 V and 4.2 V, or about therein. In further embodiments, the energy storage device (e.g., a lithium ion battery) may be configured to have a minimum operating voltage between 2.5 V and about 3 V, or about therein. In still further embodiments, the energy storage device (e.g., a lithium ion battery) is configured to have a maximum operating voltage between 4.1 V and about 4.5 V, or about therein. [Example]

[0076] Example 1: Dry composite fabrication Dry composites according to several embodiments were fabricated. Table 1 summarizes the compositions of Dry Composites Nos. 1-4. Other dry composite compositions are envisioned and can be prepared, and the disclosure herein is not limited to the specific compositions disclosed. [Table 1]

[0077] Dry composite No. 1 was fabricated by first diluting 500 mg of a solution containing 0.8 wt% single-walled carbon nanotubes (SWCNTs) and 1.2 wt% CMC with 500 mg of water. Next, 40 mg of Si / C composite and 750 mg of graphite were added to the diluted solution and mixed twice for 365 seconds at 800 rpm in a mixer to form a slurry. The slurry was then diluted with water using an overhead mixer to achieve a solids content of 40% and a viscosity of less than approximately 400 cp. The slurry was then spray-dried in a spray dryer with an airflow rate of 70 cfm, an inlet temperature of 210 °C, and a product temperature of 130 °C, a nozzle air pressure of 25 psi, a pump speed of 8 rpm, and a throughput of 45 g / min. The resulting yields were approximately 60 wt% to approximately 80 wt%.

[0078] Dry composites Nos. 2–3 were fabricated by the same process using various amounts of SWCNT and CMC solution, graphite, and Si / C composite based on the composition percentages summarized in Table 1 .

[0079] Dry composite No. 4 was fabricated by mixing the required amount of solution containing 4.9 wt% polyacrylic acid (PAA) and 0.1 wt% SWCNTs with the required amount of graphite and Si / C composite, according to the composition summarized in Table 1. The slurry was then diluted with water using an overhead mixer to achieve a solids content of 40% and a viscosity of less than approximately 400 cp. The slurry was then spray-dried in a spray dryer with an airflow rate of 70 cfm, an inlet temperature of 210 °C, and a product temperature of 130 °C, a nozzle air pressure of 25 psi, a pump speed of 8 rpm, and a throughput of 45 g / min. The resulting yield was approximately 60 wt% to approximately 80 wt%, and was in the form of a powder.

[0080] Table 2 summarizes the median diameter (D50) and percentage of Si / C composite for dry composite numbers 1–4. [Table 2]

[0081] The Si / C composite content was obtained using thermogravimetric analysis (TGA), and the D50 values ​​were obtained using particle size analyzer (PSA). The D50 values ​​increased with increasing CNT content. Furthermore, the D50 values ​​of dry composites using PAA as a binder were greater than those of dry composites using CMC as a binder. The Si / C content was close to the target range of approximately 5 wt%.

[0082] Example 2: Characterization of dry composite materials Figure 6 shows the particle size distributions of Dry Composite No. 2 and Dry Composite No. 3. Table 3 summarizes the median diameter (D50) and specific surface area (SSA) of the graphite used to fabricate the dry composites, Dry Composite No. 2, and Dry Composite No. 3. As shown in Figure 6 and Table 3, the particle size distributions of Dry Composite No. 2 and Dry Composite No. 3 do not significantly shift toward larger particle sizes from that of graphite, and the specific surface area values ​​of Dry Composite No. 2 and Dry Composite No. 3 do not change significantly from that of graphite. These experimental results indicate the absence of graphite agglomeration in Dry Composite No. 2 and Dry Composite No. 3. [Table 3]

[0083] The morphology of the dry composite was evaluated using a scanning electron microscope (SEM). FIG. 7A shows an SEM image of the surface of a dry composite according to some embodiments. FIG. 7B is a magnified SEM image of the SEM shown in FIG. 7B. In conventional dry processes, because carbon nanotubes have a large surface area, powders of active materials such as carbon nanotubes and graphite and silicon materials can undergo significant aggregation and phase separation. In contrast, as shown in FIGS. 7A and 7B, the carbon nanotubes form a network throughout the dry composite, and the Si / C composite and graphite are homogeneously dispersed in the dry composite and in contact with the carbon nanotube network.

[0084] Example 3: Preparation of dry electrodes Dry battery anodes containing dry composites according to some embodiments were fabricated. The dry electrode anodes contained, in addition to the dry composite, 2 wt. % PTFE and 0.5 wt. % polyvinylidene fluoride (PVDF). The PTFE and PVDF were first mixed with the dry composite using a non-destructive mixer at 90% intensity and 60 Hz for 5 minutes, followed by further high-shear mixing to prepare dry battery films. The resulting powders were mixed at 14-15.2 mg / cm.2 and calendering at optimal temperature and gap settings to meet the required loading of 1.5 g / cc and density of 1.5 g / cc. Finally, the dry battery film was calendered onto a carbon-coated copper sheet to fabricate a dry battery anode.

[0085] Table 4 summarizes the composition, loading, and density of dry battery anodes fabricated using dry composites No. 2 and No. 3. [Table 4]

[0086] A conventional dry battery anode without the dry composite (labeled "control") was also fabricated for comparison with the dry battery anode containing the dry composite. The control electrode was formed by first directly mixing 92.5 wt% graphite, 5 wt% Si / C composite, 2 wt% PTFE, and 0.5 wt% PVDF, and then prepared by the dry process.

[0087] The cathode was also fabricated by a dry process containing 97 wt% NMC811, 1 wt% conductive additive, and 2 wt% polymer binder.

[0088] 8 shows half-cell capacity values ​​for dry battery anodes formed with dry composite materials according to some embodiments and without the dry composite material. The dry battery anode formed without the dry composite material is labeled "Control." During half-cell testing, the half-cells were first discharged at C / 20 to 0.05 V while holding at C / 100, and then charged to 1 V at C / 20 with a C / 100 recovery rate at a temperature of 25° C.

[0089] As shown in FIG. 8 , the first cycle efficiencies (FCEs) of the dry battery anodes formed using the control anodes, dry composites No. 2 and No. 3, were approximately 89.7%, 89%, and 90.5%, respectively, indicating that the dry battery anodes containing dry composites No. 2 and No. 3 exhibited improved or at least similar first cycle efficiencies compared to dry anodes without the dry composites. The dry battery anodes formed using dry composites No. 2 and No. 3 had capacities of 418 mAh / g and 409.4 mAh / g, respectively, both of which are improvements over the capacity of the control anode (401.2 mAh / g). Furthermore, the dry battery anodes with the dry composites achieved full utilization of the calculated capacity. In contrast, the dry anodes formed without the dry composites did not achieve full utilization of the predicted capacity.

[0090] 9A shows the discharge capacity values ​​of dry battery anodes containing no CNTs, 0.25 wt % CNTs, 0.1 wt % CNTs, and 0.05 wt % CNTs in a full-cell test. The cathode in this full-cell test is an NMC811 cathode. As shown in FIG. 9A, the discharge capacities of the dry battery anodes containing no CNTs, 0.25 wt % CNTs, 0.1 wt % CNTs, and 0.05 wt % CNTs are approximately 199.8 mAh / g, 201.5 mAh / g, 199.4 mAh / g, and 201.3 mAh / g, respectively. The first cycle efficiencies (FCEs) of dry battery anodes containing no CNTs, 0.25 wt. % CNTs, 0.1 wt. % CNTs, and 0.05 wt. % CNTs are approximately 88.1%, 87.7%, 88.6%, and 86.9%, respectively. Therefore, the capacity of dry Si / C anodes with added carbon nanotubes is improved or similar to that of dry electrodes without added carbon nanotubes. The FCE of dry anodes with added carbon nanotubes is similar to that of dry electrodes without added carbon nanotubes.

[0091] Figure 9B shows the cycle life performance of dry battery anodes containing no CNTs, 0.25 wt. % CNTs, 0.1 wt. % CNTs, and 0.05 wt. % CNTs in a full-cell test. A 300 mAh pouch-type full cell was used for the test. The full cell was assembled with a dry NMC811 cathode. For each cycle, the battery was charged and discharged between 4.2 V and 2.85 V at a C / 20 rate and 40 °C. As shown in Figure 9B, the dry Si / C battery anode containing CNTs retained approximately 95% of its capacity after 100 cycles, demonstrating improved capacity retention compared to the dry Si / C battery anode without CNTs.

[0092] While certain specific embodiments have been described, these embodiments are presented by way of example and are not intended to limit the scope of the present disclosure. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms. Furthermore, various omissions, substitutions, and modifications of the systems and methods described herein may be made without departing from the spirit of the present disclosure. The appended claims and their equivalents are intended to cover such forms or modifications as are within the scope and spirit of the present disclosure.

[0093] A feature, material, characteristic, or group described in connection with a particular aspect, embodiment, or example should be understood to be applicable to any other aspect, embodiment, or example described in this section or elsewhere in this specification, unless inconsistent therewith. All features disclosed in this specification (including the accompanying claims, abstract, and drawings), and / or all steps of any method or process so disclosed, may be combined in any combination, except combinations in which at least some of such features and / or steps are mutually exclusive. Protection is not limited to the details of any foregoing embodiment. Protection extends to any novel, or any novel combination of, features disclosed in this specification (including the accompanying claims, abstract, and drawings), or any novel, or any novel combination of steps of any method or process so disclosed.

[0094] Furthermore, certain features that are described in this disclosure in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Furthermore, while features may be described above as acting in a particular combination, one or more features from a claimed combination can, in some cases, be deleted from the combination, and the combination can be claimed as a subcombination or a variation of the subcombination.

[0095] Furthermore, while operations may be shown in the figures or described herein in a particular order, such operations need not be performed in the particular order shown, or in sequential order, or even all operations need to be performed to achieve desirable results. Other operations not shown or described may be incorporated into the example methods and processes. For example, one or more additional operations may be performed before, after, simultaneously with, or between any of the described operations. Furthermore, operations may be rearranged or reordered in other implementations. Those skilled in the art will understand that in some embodiments, the actual steps performed in the illustrated and / or disclosed processes may differ from those shown in the figures. Depending on the implementation, certain of the above-described steps may be removed, and other steps may be added. Furthermore, the features and attributes of the specific embodiments disclosed above can be combined in different ways to form additional embodiments, all of which are within the scope of the present disclosure. Also, the separation of the various system components in the above-described implementations should not be understood to require such separation in all implementations, and it should be understood that the described components and systems may generally be integrated together in a single product or packaged in multiple products. For example, any of the components of the energy storage systems described herein may be provided separately or may be incorporated together (e.g., packaged together or attached together) to form an energy storage system.

[0096] For purposes of this disclosure, certain aspects, advantages, and novel features have been described herein. Not necessarily all such advantages may be achieved in accordance with any particular embodiment. Thus, for example, one skilled in the art will recognize that the present disclosure may be embodied or implemented to achieve one advantage or group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein.

[0097] Conditional language such as "can," "could," "might," or "may," unless otherwise specified or understood otherwise within the context in which it is used, is generally intended to convey that certain embodiments include certain features, elements, and / or steps, while other embodiments do not. Thus, such conditional language is generally not intended to imply that the features, elements, and / or steps are somehow required in one or more embodiments, or that one or more embodiments necessarily include logic for determining whether those features, elements, and / or steps should be included in or performed in any particular embodiment, with or without user input or prompting.

[0098] Transitive language such as the phrase "at least one of X, Y, and Z," unless otherwise specified, is understood in the context in which it is generally used to convey that an item, term, etc. can be either X, Y, or Z. Thus, such transitive language is generally not intended to imply that a particular embodiment requires the presence of at least one of X, at least one of Y, and at least one of Z.

[0099] As used herein, language of degree, such as the terms "approximately," "about," "generally," and "substantially," refers to a value, amount, or characteristic that approaches a stated value, amount, or characteristic that still performs a desired function or achieves a desired result. For example, the terms "approximately," "about," "generally," and "substantially" can refer to amounts that are less than 10%, less than 5%, less than 1%, less than 0.1%, and less than 0.01% of the stated amount, depending on the desired function or desired result.

[0100] The scope of the present disclosure is not intended to be limited by the specific disclosure of preferred embodiments in this section or elsewhere herein, but rather may be defined by the claims, as presented in this section or elsewhere herein, or as presented in the future. Claim language is to be interpreted broadly based on the language used in the claims, and not limited to the examples described herein or during the prosecution of this application, and examples are to be construed as non-exclusive.

[0101] The headings provided herein, if any, are for convenience only and do not necessarily affect the scope or meaning of the apparatus and methods disclosed herein.

Claims

1. A dry composite material for an energy storage device, comprising: a silicon active material; a carbon active material; a carbon additive; Including, The dry composite material, wherein the carbon additive, silicon active material, and carbon active material are substantially homogeneously dispersed in the dry composite material.

2. 10. The dry composite of claim 1, wherein the carbon additive is selected from the group consisting of carbon nanotubes, carbon black, carbon nanofibers, and combinations thereof.

3. 3. The dry composite material of claim 1 or 2, wherein the carbon additive is a conductive additive.

4. 4. The dry composite material according to claim 1, wherein the carbon additive forms a matrix.

5. The surface area of ​​the dry composite is at least about 1.2 m ２ The dry composite material according to any one of claims 1 to 4, wherein the tensile strength is 1 / g.

6. 6. The dry composite of claim 1, wherein the dry composite has a D50 particle size of at least about 16 μm.

7. 7. The dry composite material of claim 1, wherein the silicon active material is selected from the group consisting of silicon, silicon derivatives, and combinations thereof.

8. The silicon derivative is silicon oxide (SiO ｘ 8. The dry composite material of claim 7, wherein the composite is selected from the group consisting of silicon carbide (SiC), silicon-carbon composite (Si / C), and combinations thereof.

9. 9. The dry composite material of claim 1, wherein the carbon active material comprises graphite, soft carbon, hard carbon, and combinations thereof.

10. 10. The dry composite material of claim 1, further comprising a composite binder.

11. 11. The dry composite material of claim 10, wherein the composite binder is selected from the group consisting of polyacrylic acid (PAA), cellulose, alginate (Alg), acrylate, acrylamide, polyacrylamide (PAM), gum, sulfonated tetrafluoroethylene-based fluoropolymer-copolymer, network polymer, acrylonitrile, amide-based binder, imide-based binder, amide-imide binder, polyvinylidene fluoride (PVDF), copolymers thereof, and combinations thereof.

12. 12. The dry composite material of any one of claims 1 to 11, which is substantially free of solvent residues.

13. An electrode film comprising the dry composite material of any one of claims 1 to 12.

14. 14. The electrode film of claim 13, further comprising a dry binder.

15. 15. The electrode film of claim 14, wherein the dry binder is selected from the group consisting of polytetrafluoroethylene (PTFE), ultra-high molecular weight polyethylene (UHMWPE), polyvinylidene fluoride (PVDF), acrylates, acrylonitrile imides, amides, and combinations thereof.

16. 16. The electrode film of any one of claims 13 to 15, which is self-supporting and substantially free of solvent residues.

17. 17. An electrode comprising the electrode film of claim 13 disposed on a current collector.

18. 20. An energy storage device comprising the electrode of claim 17.

19. 20. The energy storage device of claim 18, wherein the capacity of the electrode after 100 cycles is at least about 95% of the capacity of the electrode in the first cycle.

20. 20. The energy storage device of claim 18 or 19, wherein the capacity of the electrode is at least about 400 mAh / mg on the first cycle.

21. 1. A method for preparing a dry composite material for an energy storage device electrode, comprising: forming a mixture including a silicon active material, a carbon active material, and a carbon additive; forming the dry composite material including the silicon active material, the carbon active material, and the carbon additive, wherein the carbon additive, the silicon active material, and the carbon active material are substantially homogeneously dispersed throughout the dry composite material; A method comprising:

22. 22. The method of claim 21, wherein the mixture is a slurry and further comprises a solvent, and forming the dry composite further comprises removing the solvent.

23. 23. The method of claim 21 or 22, wherein the mixture further comprises a complex binder.

24. 24. The method of any one of claims 21 to 23, wherein the step of forming the dry composite is a process selected from the group consisting of spray drying, triple kneader mixing, fluidized bed mixing, freeze-drying mixing, milling, mechanofusion, and combinations thereof.

25. 1. A method for preparing a dry electrode film for an energy storage device electrode, comprising: mixing the dry composite material of any one of claims 1 to 12 with a dry binder to form a dry bulk mixture; forming a free-standing dry electrode film from the dry electrode film mixture; A method comprising:

26. 26. The method of claim 25, wherein the step of forming the free-standing dry electrode film is a dry process.

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