Silicon composite anode materials for energy storage devices and methods thereof

Abstract

Methods for forming dry composites for energy storage device electrodes are provided. The method may include forming a slurry by mixing a solvent, a silicon active material, a carbon active material, and a carbon additive; and forming a dry composite including a silicon active material, a carbon active material, and a carbon additive by removing the solvent. The carbon additive, the silicon active material, and the carbon active material are substantially uniformly dispersed in the dry composite. The dry composite may be used to form a dry electrode film in a dry manufacturing process.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 377,982, filed on September 30, 2022, entitled “Silicon Composite Anode Materials and Methods for Energy Storage Devices,” and the entire contents of that application are incorporated herein by reference. Technical Field

[0003] The present invention relates generally to energy storage devices and, in particular, to materials and methods for dry electrode membranes including silicon active materials. Background Art

[0004] Lithium-ion batteries have long been used as a power source in many commercial and industrial applications, for example, in consumer devices, production equipment, and battery-powered vehicles. One way to increase the storage potential of energy storage devices is to use active materials with high theoretical capacities, such as silicon materials such as silicon, silicon oxide (SiO x ), silicon carbon (SiC) or silicon carbon composite (Si / C). The theoretical capacity of silicon is about 3560 mAh / g, which is about 10 times the capacity of graphite 356 mAh / g. However, due to the mechanical properties of the membrane components and the interactions between them, the performance of the electrode membrane may be reduced. Specifically, additional degradation can be observed in electrodes doped with silicon materials, which can experience significant volume changes during battery cycling.

[0005] A method for maintaining electrical contact during the electrode cycle including silicon material is to use carbon additives, such as carbon nanotubes (CNT) and carbon black, to form a carbon matrix on the electrode. In conventional wet electrode film processes, it is possible to evenly distribute adhesives, graphite, carbon additives and silicon materials. However, without the use of processing solvents, it may be more difficult to evenly disperse adhesives, graphite, silicon materials and / or carbon additives. Therefore, new ingredients and processes for improving material dispersion in electrode films are necessary. Summary of the invention

[0006] To summarize the invention and the advantages achieved over the prior art, certain objects and advantages of the invention are described herein. Not all of these 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 in a manner that achieves or optimizes one advantage or group of advantages taught herein without necessarily achieving other objects or advantages taught or suggested herein.

[0007] 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 uniformly dispersed throughout the dry composite material.

[0008] 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.

[0009] In some embodiments, the surface area of ​​the dry composite material is at least about 1.2 m 2 / g. In some embodiments, the D50 particle size of the dry composite material is 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 selected from silicon oxide (SiO x ), silicon carbide (SiC), silicon carbon composite (Si / C) and a group consisting of a combination thereof. In some embodiments, the carbon active material includes graphite, soft carbon, hard carbon and a combination thereof. In some embodiments, the dry composite material further includes a composite adhesive. In some embodiments, the composite adhesive is selected from the group consisting of polyacrylic acid (PAA), cellulose, alginate (Alg), acrylate, acrylamide, polyacrylamide (PAM), gum, sulfonated tetrafluoroethylene-based fluoropolymer copolymer, mesh polymer, acrylonitrile, amide-based adhesive, imide-based adhesive, amide-imide adhesive, polyvinylidene fluoride (PVDF), its copolymers and a combination thereof. In some embodiments, the dry composite material is substantially free of solvent residues.

[0010] In another aspect, an electrode membrane comprising a dry composite material is disclosed. In some embodiments, the electrode membrane 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), acrylates, acrylonitrile imide, amides and combinations thereof. In some embodiments, the electrode membrane is self-supporting and substantially free of solvent residues.

[0011] In another aspect, an electrode is disclosed, comprising an electrode film disposed on a current collector. In another aspect, an energy storage device is disclosed, comprising an electrode. In some embodiments, the capacity of the electrode after 100 cycles is at least about 95% of the capacity of the electrode in the first cycle. In some embodiments, the capacity of the electrode in the first cycle is at least about 400 mAh / mg.

[0012] In another aspect, a method for preparing a dry composite material for an electrode of an energy storage device 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 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 uniformly dispersed in the dry composite material.

[0013] In some embodiments, the mixture is a slurry and further comprises a solvent, and wherein 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, three-kneader mixing, fluidized bed mixing, freeze-dry mixing, grinding, mechanical fusion, and combinations thereof.

[0014] 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.

[0015] All of these embodiments are within the scope of the invention disclosed herein. These and other embodiments of the present invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiments with reference to the accompanying drawings, and the present invention is not limited to any particular preferred embodiment (one or more) disclosed. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] These and other features, aspects, and advantages of the present disclosure are described with reference to the accompanying drawings of certain embodiments, which are intended to illustrate certain embodiments rather than to limit the present invention.

[0017] Figure 1 is a schematic diagram of an energy storage device including one or more electrode membranes.

[0018] Figure 2 is an illustration of a dry composite material according to some embodiments.

[0019] Figure 3 is a process flow diagram of an embodiment of a process for forming a dry composite material.

[0020] Figure 4A is a schematic diagram of an embodiment of an apparatus for producing a dry composite material.

[0021] Figure 4B is a process flow diagram of an embodiment of a process for forming a dry composite material.

[0022] Figure 5is a process flow chart of an embodiment of a process for forming a dry electrode film.

[0023] Figure 6 A line graph illustrating the size distribution of dry composite materials according to some embodiments and a control material is shown.

[0024] Fig. 7A is a scanning electron microscope (SEM) image of a dry composite surface according to some embodiments.

[0025] Figure 7B is a scanning electron microscope (SEM) image of a dry composite surface according to some embodiments, and is from Fig. 7A A more focused image of the SEM image.

[0026] Figure 8 Bar graphs and line graphs are illustrated of capacity and first cycle efficiency (FCE) of half-cells fabricated with anodes including dry composite materials according to some embodiments and control anodes.

[0027] Fig.9A Bar graphs and line graphs of capacity and first cycle efficiency (FCE) of full cells having anodes including dry composite materials according to some embodiments and control anodes are illustrated.

[0028] Fig. 9B A line graph is shown of capacity retention of full cells having anodes including dry composite materials according to some embodiments and control anodes. DETAILED DESCRIPTION

[0029] Various embodiments of dry composite materials and electrode films for energy storage devices are provided herein. Specifically, in certain embodiments, the energy storage device disclosed herein includes an electrode film, which includes a dry composite material, and the dry composite material includes a silicon active material, a carbon active material, and a carbon additive (e.g., carbon nanotubes). When the dry composite material is used in a dry electrode film manufacturing process, the electrode film produced is found to exhibit improved uniformity, stability, and electrical properties. Methods for processing such dry composite materials and incorporating dry composite materials into electrode films are also provided. The present disclosure discloses that when a dry composite material is manufactured and used in an electrode film, an improvement in the uniformity of material distribution in the electrode film can be achieved.

[0030] Dry electrode membranes made using dry composite materials made by one or more processes described herein can exhibit improved electrical properties, for example, due to improved uniform distribution of one or more components of the electrode membrane. Disclosed herein are materials and methods for providing more uniform distribution and less aggregation of active materials (one or more) during manufacturing. Certain embodiments of the energy storage device provided herein can provide a more uniform distribution of graphite materials and / or silicon active materials after processing. In particular, self-supporting and / or self-supporting electrode membranes including such active materials (one or more) are provided. One or more processes described herein can avoid aggregation, poor distribution, phase separation and packaging failure of active materials. In some embodiments, when the use of high shear devices and associated appliances, such as air compressors and / or associated mixers, is reduced or eliminated, manufacturing costs can be reduced.

[0031] limited

[0032] As used herein, the terms "battery" and "capacitor" have their ordinary and customary meanings as given to those of ordinary skill in the art. The terms "battery" and "capacitor" are not mutually exclusive. A capacitor or battery may refer to a single electrochemical cell that may operate alone or as a component of a multi-battery system.

[0033] As used herein, the voltage of an energy storage device is the operating voltage of a single battery or capacitor unit. The voltage may exceed the rated voltage or be below the rated voltage under load, or according to manufacturing tolerances.

[0034] As provided herein, a "self-supporting" electrode film is an electrode film mixed with an adhesive matrix structure, which is sufficient to support the film or layer and maintain its shape so that the electrode film or layer can be self-supporting. When incorporated into an energy storage device, a self-supporting electrode film or active layer is an electrode film or active layer mixed with such an adhesive matrix structure. In general, and depending on the method used, such electrode films or active layers are strong enough to be used in energy storage device manufacturing processes without any external support elements (such as current collectors, support nets or other structures), although support elements can be used to facilitate energy storage device manufacturing processes. For example, a "self-supporting" electrode film can have sufficient strength to be rolled up, processed and unfolded in an electrode manufacturing process without other support elements. A "self-supporting" electrode film is a self-supporting electrode film without an external support element. A dry electrode film such as a cathode electrode film or an anode electrode film can be self-supporting.

[0035] As described herein, "solvent-free" electrode films refer to electrode films that do not contain detectable processing solvents, processing solvent residues, or processing solvent impurities. Processing solvents or traditional solvents include organic solvents. Dry electrode films such as cathode electrode films or anode electrode films can be solvent-free.

[0036] A "wet" electrode or "wet process" electrode is an electrode prepared by at least one step involving a slurry of active material(s), binder(s), and processing solvent, processing solvent residues, and / or processing solvent impurities. A wet electrode may optionally include additive(s). Even after the electrode film is subjected to a drying step, a wet electrode may still contain solvent, solvent residues, and / or solvent impurities due to the solvent trapped within the volume of the electrode film and the finite temperature and / or drying time that needs to be applied to the electrode in order to maintain performance.

[0037] As used herein, a "dry" composite material is a composite material that contains no or substantially no or contains detectable amounts of processing solvent, processing solvent residues, and / or processing solvent impurities. A composite material manufactured by a process that may include a solvent (e.g., a slurry of a material) may be a "dry" composite material, such as by a manufacturing process that substantially evaporates the solvent, solvent residues, and solvent impurities and / or an additional drying process step.

[0038] Energy storage devices

[0039] Figure 1A side cross-sectional schematic diagram of an example of an energy storage device 100 is shown. The energy storage device 100 can be any number of energy storage devices, such as a lithium ion capacitor, a lithium ion battery, or a double-layer capacitor. Of course, other energy storage devices are also within the scope of the present invention, and the device 100 can be other types of capacitors, batteries, capacitor-battery hybrids, or fuel cells. The energy storage device 100 can have a first electrode 102, a second electrode 104, and a separator 106 located between the first electrode 102 and the second electrode 104. For example, the first electrode 102 and the second electrode 104 can be placed adjacent to the respective opposite surfaces of the separator 106. The first electrode 102 can include a cathode, and the second electrode 104 can include an anode, and 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 can contact the first electrode 102, the second electrode 104, and the separator 106. The electrolyte, first electrode 102, second electrode 104, and separator 106 may be received within an energy storage device housing 120. For example, the energy storage device housing 120 may be sealed after inserting the first electrode 102, second electrode 104, and separator 106 and impregnating the energy storage device 100 with the electrolyte, such that the first electrode 102, second electrode 104, separator 106, and electrolyte may be physically sealed from the environment outside the housing.

[0040] The separator 106 can be configured to electrically insulate two electrodes adjacent to opposite sides of the separator 106, such as the first electrode 102 and the second electrode 104, while allowing ions between the two adjacent electrodes to communicate. The separator 106 may include a variety of porous or non-woven 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 and ceramics and / or metal oxides. 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 non-woven 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 non-woven polypropylene (PP) material. The separator 106 may include a polyethylene coating, such as on a porous or non-woven polypropylene material or a composite of a polymeric material.

[0041] like Figure 1As shown, 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 coupling between the corresponding electrode and an external circuit (not shown). The first current collector 108 and the second current collector 110 may include 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 charge transfer between the corresponding electrode and the external circuit. For example, the first current collector 108 may be electrically coupled to the first energy storage device terminal 122, such as a positive terminal, via the first connector 126. The second current collector 110 may be electrically coupled to the second energy storage device terminal 124, such as an electric negative terminal, via the second connector 128. The first energy storage device terminal 122 and the second energy storage device terminal 124 may be electrically coupled to the corresponding terminals of the external circuit to couple the energy storage device 100 to the external circuit.

[0042] The current collector may include a metallic material, such as a material including aluminum, nickel, copper, silver, alloys thereof, and / or other metallic materials, or a non-metallic material, such as graphite that remains inert at the electrode potential of the device. In some embodiments, the current collector also includes a coating. In some embodiments, the coating includes a carbon coating. The first current collector 108 and / or the second current collector 110 may include a foil. The first current collector 108 and the second current collector 110 may have a rectangular or substantially rectangular shape and are sized to provide the desired charge transfer between the corresponding electrode and the external circuit. The energy storage device 100 may include any of a variety of different configurations to provide the electrical communication between the electrodes 102, 104 and the external circuit through the current collectors 108, 110, respectively. For example, the transfer may be provided via a collector plate and / or another energy storage device component.

[0043] The first electrode 102 may have a first electrode film 112 (e.g., an upper electrode film) on a first surface of the first current collector 108 (e.g., on a top surface of the first current collector 108). The first electrode 102 may have a second electrode film 114 (e.g., a lower 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., an upper electrode film) on a first surface of the second current collector 110 (e.g., on 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, the first surface of the second current collector 110 may face the second surface of the first current collector 108, so 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.

[0044] Electrode films 112, 114, 116 and / or 118 may have various suitable shapes, sizes and / or thicknesses. For example, the electrode film may have a thickness of about 30 microns (μm) to about 2000 microns, including about 100 microns to about 250 microns, and also including about 30 microns to about 250 microns. Electrode films 112, 114, 116 and / or 118 may have the same or different thicknesses, compositions and densities with respect to each other. For example, electrode films 112 and electrode films 114 may have different thicknesses, compositions or densities compared to electrode films 116 and 118.

[0045] In some embodiments, the electrode film of the anode and / or cathode of the energy storage device includes 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, so that the electrode film includes a dry binder material and a dry composite material.

[0046] In some embodiments, the electrode film of anode and / or cathode may include one or more dry adhesive materials. In some embodiments, dry adhesive may include copolymers of polytetrafluoroethylene (PTFE), polyolefins, polyalkylenes, polyethers, styrene-butadiene, polysiloxanes and polysiloxanes, branched polyethers, polyvinyl ethers, copolymers thereof and / or mixtures thereof. Adhesive may include cellulose, such as carboxymethyl cellulose (CMC). In some embodiments, polyolefins may include polyethylene (PE), polypropylene (PP), polyvinylidene fluoride (PVDF), copolymers thereof and / or mixtures thereof. For example, adhesive may include polyvinyl chloride, polyphenylene oxide (PPO), polyethylene block polyethylene glycol, polyethylene oxide (PEO), polyphenylene oxide (PPO), polyethylene block polyethylene glycol, polydimethylsiloxane (PDMS), polydimethylsiloxane-polyalkylmethylsiloxane, copolymers thereof and / or mixtures thereof. In some embodiments, dry adhesive may be a thermoplastic. In some embodiments, dry adhesive includes a fibrillated polymer. In certain embodiments, dry binder material can comprise one or more various suitable polymeric materials, such as polytetrafluoroethylene (PTFE), ultra-high molecular weight polyethylene (UHMWPE), polyvinylidene fluoride (PVDF), acrylate (for example, melt-processable acrylate), acrylonitrile imide, amide, adhesive provided by this paper and / or other suitable and optional fibrillated material, used alone or in combination.In certain embodiments, electrode film can comprise polymer, such as polymer binder material, and one or more other components.Polymer is a general term, and can comprise the mixture of homopolymer, copolymer and polymer provided by this paper.In certain embodiments, polymer can be dry binder material. In some embodiments, the electrode film may include a dry binder that is or is approximately 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, for example, from about 1 wt% to about 10 wt%, where wt% is based on the weight of the electrode film.

[0047] In some embodiments, the electrode film of the anode and / or cathode may include one or more active electrode components. In some embodiments, the active electrode component may be selected from silicon active materials, carbon active materials, and combinations thereof. In some embodiments, the silicon active material may be selected from 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 configured to reversibly intercalate lithium ions, such as graphite, soft carbon, and / or hard carbon. In some embodiments, the electrode film and / or active electrode component may include additional active electrode materials. In some embodiments, the additional active electrode material may be selected from insertion materials (e.g., carbon and / or graphene), alloying / de-alloying materials (e.g., epoxides, tin, and / or tin oxide), metal alloys or compounds (e.g., Si-Al and / or Si-Sn), and / or conversion materials (e.g., manganese oxide, molybdenum oxide, nickel oxide, and / or copper oxide). Additional active materials may be used alone or mixed together to form a multi-phase 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 component may be doped with a lithium-rich ion source for pre-lithiation of the anode, advantageously reducing or eliminating the low efficiency of the first cycle. In some embodiments, the electrode film may include an active material that is or is about 40wt%, 45wt%, 50wt%, 55wt%, 60wt%, 65wt%, 70wt%, 75wt%, 80wt%, 82wt%, 84wt%, 85wt%, 87wt%, 89wt%, 90wt%, 92wt%, 95wt%, 97wt%, 99wt% or 99.5wt%, or any range of values ​​therebetween, for example, from about 40wt% to about 99.5wt%, where wt% is based on the weight of the electrode film. In some embodiments, the electrode film may include about 1wt% to about 10wt% of active silicon material and about 40wt% to about 99.5wt% of carbon active material.

[0048] In some embodiments, the electrode film of the anode and / or cathode may include one or more additives, including additives that promote electrical conductivity or ionic conductivity. In some embodiments, the electrical conductivity promoting additive may be a carbon additive. In some embodiments, the carbon additive may include carbon nanotubes (CNT), carbon black, carbon nanofibers (CNF) and combinations thereof. In some embodiments, CNT may include single-walled carbon nanotubes (SWCNT), double-walled carbon nanotubes (DWCNT), few-walled carbon nanotubes (FWCNT), multi-walled carbon nanotubes (MWCNT) and combinations thereof. In some embodiments, carbon black may include conductive carbon black. In some embodiments, 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 a carbon additive that is or is approximately 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 of values ​​therebetween, for example, from about 0.05 wt% to about 4 wt%, where wt% is based on the weight of the electrode film.

[0049] In some embodiments, the electrode film may include a dry composite material that is or is approximately 80wt%, 82wt%, 84wt%, 86wt%, 88wt%, 90wt%, 91wt%, 92wt%, 93wt%, 94wt%, 95wt%, 96wt%, 97wt%, 98wt%, 99wt%, 99.5wt%, or any range of values ​​therebetween, for example, from about 90wt% to about 99.5wt%, about 95wt% to about 99.5wt%, about 97wt% to about 98wt%, where the wt% is based on the weight of the electrode film.

[0050] In some embodiments, the electrode membrane is a dry and / or self-supporting membrane electrode membrane, which can provide a high electrode material loading or a high active material loading (which can be expressed as the electrode membrane mass per unit area of ​​the electrode membrane or current collector), which is or is about 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, for example, about 10 mg / cm 2 To about 50mg / cm 2 .

[0051] In some embodiments, the electrode film density of the electrode film may be or is about 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 , about 3.4g / cm 3 , about 3.5g / cm 3 , about 3.6g / cm 3 , about 3.7g / cm 3 or about 3.8g / cm 3 , or any range of values ​​therebetween, for example, about 0.8 g / cm 3 To about 3.8g / cm 3 .

[0052] Dry composite materials

[0053] Dry composite materials can include carbon additives and active materials. In some embodiments, carbon additives can include carbon nanotubes (CNT), carbon black, carbon nanofibers (CNF) and combinations thereof. In some embodiments, CNT can include single-walled carbon nanotubes (SWCNT), double-walled carbon nanotubes (DWCNT), few-walled carbon nanotubes (FWCNT), multi-walled carbon nanotubes (MWCNT) and combinations thereof. In some embodiments, carbon black can include conductive carbon black. In some embodiments, carbon black can include acetylene black (AB), super P conductive carbon black, Ketjenblack (KB) carbon black and combinations thereof. In some embodiments, the elements (e.g., active materials and carbon additives) of dry composite materials are substantially uniformly dispersed. In some embodiments, the elements (e.g., active materials and carbon additives) of dry composite materials are substantially not aggregated or agglomerated. Figure 2 is an example illustration of a dry composite material, wherein the dry composite material may include Si / C as a silicon active material, graphite as a carbon active material, a polymer composite binder, and CNTs uniformly dispersed therein. In some embodiments, the carbon nanotubes are single-walled carbon nanotubes (SWCNTs).

[0054] 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 selected from 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, 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 configured to reversibly embed lithium ions, such as graphite, soft carbon, and / or hard carbon.

[0055] In some embodiments, the dry composite material may include additional active electrode materials. In some embodiments, the additional active electrode materials may be selected from intercalation materials (e.g., carbon and / or graphene), alloying / de-alloying materials (e.g., epoxides, tin and / or tin oxide), metal alloys or compounds (e.g., Si-Al and / or Si-Sn), and / or conversion materials (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, SiO x -C, SnOx-C, Si-Sn, Si-SiO x、Sn-SnOx、Si-SiO x -C, Sn-SnOx-C, Si-Sn-C, SiO x -SnOx-C, Si-SiO x -Sn or Sn-SiO x -SnOx).

[0056] In certain embodiments, dry composite material can also include composite adhesive.In certain embodiments, composite adhesive can include polymer adhesive.In certain embodiments, composite adhesive can include water-based adhesive, organic solvent-based adhesive and combination thereof.In certain embodiments, composite adhesive can be selected from polyacrylic acid (PAA), cellulose (for example, carboxymethyl cellulose (CMC), alginate (Alg) (for example, sodium alginate (Na-Alg)), acrylate (for example, polymethyl methacrylate (PMMA), Li-PMMA), acrylamide, polyacrylamide (PAM), gum (for example, gum arabic, guar gum, chitosan, dextran), sulfonated tetrafluoroethylene-based fluoropolymer copolymer (for example, Nafion), mesh polymer (for example, interpenetrating polymer network (IPN)), acrylonitrile (for example, water-based acrylonitrile (for example, acrylonitrile multi-polymer adhesive (LA-133)), amide-based adhesive, imide-based adhesive, amide-imide adhesive, polyvinylidene fluoride (PVDF), its copolymer (for example, PAA-PVA, PAA-CMC) and combination thereof.

[0057] In some embodiments, the dry composite material may include impurities. In some embodiments, the impurities include aluminum, chromium, iron, lithium, magnesium, manganese, sodium, nickel, sulfur, zinc, and combinations thereof. In some embodiments, the dry composite material may include impurities that are or are approximately 10000ppm, 8000ppm, 5000ppm, 3000ppm, 2000ppm, 1000ppm, 800ppm, 700ppm, 500ppm, 100ppm, 50ppm, or any range of values ​​therebetween, for example, from about 50ppm to about 10000ppm.

[0058] In some embodiments, the dry composite material may include particles. In some embodiments, the particles may be dry particles that do not contain solvent. In some embodiments, the median particle size (D50) of the dry composite material may be or is about 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, for example, from about 10 μm to about 30 μm. In some embodiments, the specific surface area of ​​the dry composite material may be or is about 1 m 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, for example, from about 1 m 2 / g to about 2m 2 / g.

[0059] In some embodiments, the advantage of the present application is that the carbon additive, silicon active material and / or carbon active material are uniformly dispersed or substantially uniformly dispersed throughout the dry composite material. In some embodiments, compared with electrode films manufactured without dry composite materials, the aggregation and / or phase separation of active materials and / or carbon additives in dry composite materials and dry electrode films manufactured using dry composite materials are reduced or significantly reduced, which can be described as substantially uniformly dispersed or uniformly dispersed. For example, in some embodiments, the median particle size (D50) of the dry composite material can be, can be about, can be at most, or can be at most about 300%, 275%, 250%, 225%, 200%, 175%, 150%, 140%, 130%, 120%, 110%, 100%, 90% or 80% of the median particle size (D50) of silicon active materials and / or carbon active materials, or any value range therebetween. In another example, in some embodiments, the specific surface area of ​​the dry composite material can be, can be about, can be at most, or can be at most 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 value range therebetween. In additional examples, in some embodiments, the particle aggregation in the dry electrode film can be, can be about, can be at most, or can be at most about 15 times, 10 times, 9 times, 8 times, 7 times, 6 times, 5 times, 4 times, 3 times, 2 times or 1.5 times the size of the carbon active material and / or the silicon active material, or any value range therebetween.

[0060] In some embodiments, the dry composite material can include a carbon additive that is or is about 0.01 wt%, 0.05 wt%, 0.1 wt%, 0.15 wt%, 0.20 wt%, 0.25 wt%, or about 0.01 wt%, 0.05 wt%, 0.05 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, from about 0.01 wt% to about 1 wt%, where wt% is based on the weight of the dry composite material. In some embodiments, the dry composite material may include a silicon active material having a weight percentage of 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, for example, from about 2 wt% to 10 wt%, wherein the wt% is based on the weight of the dry composite material. In some embodiments, the dry composite material may include a carbon active material having a weight percentage of 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, for example, from about 75 wt% to 99 wt%, wherein the wt% is based on the weight of the dry composite material.

[0061] Method for manufacturing dry composite materials

[0062] A dry composite material may be produced and then may be used to make an electrode film. In some embodiments, the dry composite material may be formed by a slurry process and / or a solvent-free process.

[0063] Figure 3 30 is a process flow diagram of an embodiment of a process 300 for forming a dry composite material. The method of forming the dry composite material 300 may include forming a mixture including a carbon additive and an active material in step 302. In some embodiments, the active material may be or include any active material (e.g., an 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 is selected from 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 additives may include soft carbon, hard carbon, graphite (e.g., natural graphite and artificial graphite) and combinations thereof. In some embodiments, the carbon additives 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 material, such as a composite binder. In some embodiments, such as in a spray drying process, the mixture may be a slurry and also include a liquid. In step 304, a dry composite material may be formed from the mixture. In some embodiments, the dry composite material may be formed by a method selected from spray drying, three-kneader mixing, fluidized bed mixing, freeze-dry mixing, grinding, mechanical fusion and combinations thereof. In some embodiments, such as in a spray drying process, the dry composite material may be formed by removing liquid and / or solvent from the mixture. In some embodiments, the dry composite material may be substantially free of solvent or liquid. In some embodiments, the dry composite material may maintain a substantially uniform distribution of components (e.g., carbon additives, active materials and / or composite binders) in the dry composite material. In some embodiments, the resulting yield of the process for forming a dry composite material can be or can be approximately 40 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 80 wt% or 90 wt%, or any range of values ​​therebetween, for example, from about 40 wt% to about 90 wt%, where wt% is based on the weight of the mixture.

[0064] Figure 4A and Figure 4B Schematically illustrates a spray drying apparatus for forming a dry composite material and a method of using such a spray drying apparatus according to some embodiments. Figure 4A and Figure 4BAs shown, in step 420, a slurry can be formed in a container 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 a 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 material 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 a carbon nanotube. In some embodiments, the slurry can be formed by mixing the ingredients with a mixer. In some embodiments, the slurry can also be diluted to achieve a desired solid content weight percentage. In step 422, the slurry can enter the drying chamber 406 through the nozzle 404 for spray drying. After the slurry is spray dried in the chamber 406 in step 422, in step 424, a dry composite material can be formed and transported to the cyclone separator 408, and then collected in the powder collector 412. The dust collector 410 can be configured to collect any dust from the slurry that does not form a dry composite material.

[0065] In some embodiments, the slurry can be formed by mixing the components of the dry composite material (e.g., carbon additives and active materials; carbon additives, active materials and composite binders; or carbon additives, carbon active materials, silicon active materials and composite binders) with a liquid. In some embodiments, the liquid may include an aqueous solvent and / or an organic solvent. In some embodiments, the liquid may include water. In some embodiments, the components of the mixture (e.g., carbon additives, active materials, binders, and liquids) may be substantially uniformly mixed and / or distributed in the slurry mixture. In some embodiments, the slurry may be formed by mixing a solution including a carbon additive and a composite binder with a carbon active material and a silicon active material. In some embodiments, the solution can include a carbon additive that is or is about 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, for example, from about 0.1 wt% to about 4 wt%, where wt% is based on the weight of the solution. In some embodiments, the solution can include a composite binder that is or is about 0.5wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt%, 4.9wt%, 5wt%, 5.5wt%, 6wt%, 6.5wt%, 7wt%, 7.5wt%, 8wt%, 8.5wt%, 9wt%, 9.5wt% or 10wt%, or any range of values ​​therebetween, for example, from about 0.5wt% to about 10wt%, where wt% is based on the weight of the solution. In some embodiments, a slurry can be formed by mixing a solution (e.g., where the solution can include a carbon additive, a composite binder, a carbon active material, and a silicon active material) for a certain period of time using a mixer. In certain embodiments, mixing time can be or can be approximately 200 seconds, 250 seconds, 300 seconds, 350 seconds, 365 seconds, 400 seconds, 450 seconds, 500 seconds, 550 seconds or 600 seconds, or any value range therebetween, for example, from about 200 seconds to about 600 seconds. In certain embodiments, mixing can be carried out more than once, such as twice, three times, four times, five times, six times or any required number of times. In certain embodiments, the speed of mixer can be or can be approximately 500rpm, 600rpm, 700rpm, 750rpm, 800rpm, 850rpm, 900rpm, 1000rpm, 1100rpm, 1200rpm, 1300rpm, 1400rpm or 1500rpm, or any value range therebetween, for example, from about 500rpm to about 1500rpm.

[0066] In some embodiments, after the slurry is formed, the slurry can be further diluted. In some embodiments, the diluted slurry can include diluting the slurry to achieve a solid content of or about 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, 45wt%, 50wt%, 55wt% or 60wt%, or any value range therebetween, for example, about 20wt% to about 60wt%, wherein wt% is based on the weight of the slurry. In some embodiments, the diluted slurry can include diluting the slurry to achieve a viscosity of or about 500cp, 450cp, 400cp, 350cp, 300cp, 250cp, 200cp, 150cp or 100cp, or any value range therebetween, for example, from about 100cp to about 500cp. In some embodiments, dilution can be achieved by using a mixer (e.g., an overhead mixer).

[0067] In some embodiments, when a slurry mixture of components is used, the method of removing the solvent from the slurry can be spray drying. In some embodiments, the airflow rate of spray drying can be or can be about 50cpm, 55cpm, 60cpm, 65cpm, 70cpm, 75cpm, 80cpm, 85cpm, 90cpm, 95cpm or 100cpm, or any value range therebetween, for example, from about 50cpm to about 100cpm. In some embodiments, the inlet temperature of spray drying can be or can be about 150°C, 170°C, 190°C, 200°C, 210°C, 230°C, 250°C, 270°C, 290°C or 300°C, or any value range therebetween, for example, from about 150°C to about 300°C. In some embodiments, the spray-dried product temperature can be or can be about 80° C., 90° C., 100° C., 110° C., 130° C., 150° C., 170° C., 190° C., or 200° C., or any range of values ​​therebetween, for example, from about 80° C. to about 200° C. In some embodiments, the spray-dried throughput can be or can be about 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 of values ​​therebetween, for example, from about 20 g / min to about 80 g / min.

[0068] Methods for using dry composite materials in the manufacture of electrode membranes and energy storage devices

[0069] Dry composite materials can be used to form electrode films. Electrode films comprising dry composite materials can be used to form electrodes and energy storage devices, such as those described herein. Advantageously, the dry electrode films disclosed herein may include a conductive carbon network passing through the dry electrode film in contact with a carbon active material and / or a silicon active material. In addition, the aggregation and phase separation of active materials can be significantly reduced compared to dry electrode films made with raw materials instead of using dry composite materials. Therefore, the cycle life performance and capacity of energy storage devices manufactured with dry electrode films according to some embodiments can be improved, and the expected capacity can be fully utilized.

[0070] After forming the dry composite material, the dry composite material can be used to form a dry electrode film. In some embodiments, the dry electrode film including the dry composite material can be manufactured by a dry or wet manufacturing process. As used herein, a dry manufacturing process or a dry process can refer to a process that does not use or substantially does not use a solvent in the formation of the electrode film.

[0071] For example, Figure 5 FIG. 5 is a process flow diagram of an embodiment of a process 500 for forming a dry electrode film. Figure 5 As shown, a dry electrode film mixture including a dry composite material and a dry binder may be mixed in step 502. 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 manufacturing process.

[0072] In some embodiments, the components of the active layer or electrode film may include dry particles, such as dry composite materials. Dry particles used to form 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 by an electrode film mixture so that the weight percentage of the components of the active layer or electrode film and the weight percentage of the components of the electrode film mixture are substantially the same. In some embodiments, the active layer or electrode film formed by the electrode film mixture using a dry manufacturing process may be free of or substantially free of any processing additives, such as solvents and solvent residues obtained therefrom. In some embodiments, the resulting active layer or electrode film is a self-supporting film formed by a dry particle mixture using a dry process. In some embodiments, the resulting active layer or electrode film is a self-supporting film formed by an electrode film mixture using a dry process. The process of forming the active layer or electrode film may include fibrillating the fibrillating binder component (one or more) so that the film may include a fibrillating binder. In other embodiments, a self-supporting active layer or electrode film may be formed without a current collector. In further embodiments, the active layer or electrode film may include a fibrillated polymer matrix so that the film is self-supporting. It is thought that a matrix, grid or network of fibrils may be formed to provide mechanical structure to the electrode membrane.

[0073] In some embodiments, the electrode film mixture may include a dry binder that is or is approximately 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%, 8.5 wt%, 9 wt%, 9.5 wt% or 10 wt%, or any range of values ​​therebetween, for example, from about 1 wt% to about 10 wt%, where wt% is based on the weight of the electrode film mixture.

[0074] In some embodiments, dry adhesive can include polymer adhesive.In some embodiments, dry adhesive can include copolymers of polytetrafluoroethylene (PTFE), polyolefin, polyalkylene, polyether, styrene-butadiene, polysiloxane and polysiloxane, branched polyether, polyvinyl ether, its copolymer and / or its mixture. Adhesive can include cellulose, such as carboxymethyl cellulose (CMC).In some embodiments, polyolefin can include polyethylene (PE), polypropylene (PP), polyvinylidene fluoride (PVDF), its copolymer and / or its mixture.For example, adhesive can include polyvinyl chloride, polyphenylene oxide (PPO), polyethylene block polyethylene glycol, polyethylene oxide (PEO), polyphenylene oxide (PPO), polyethylene block polyethylene glycol, polydimethylsiloxane (PDMS), polydimethylsiloxane-polyalkylmethylsiloxane, its copolymer and / or its mixture.In some embodiments, adhesive can be thermoplastic.In some embodiments, dry adhesive can include fibrillated polymer.

[0075] In some embodiments, the size of the components and / or particles of the electrode film mixture can be reduced by using high shear apparatus and processes (such as jet milling). High shear forces can be provided to separate the binder material aggregates into finely divided particles and / or to fibrillate the binder material so that the binder material can be coated with other electrode film components. In some embodiments, the dry processing powder obtained can be compressed under heat and pressure using a roller mill to form a film, such as by bonding and adhering to other components of the film by PTFE, for example, in a fibrillated matrix. The thickness of the film can depend on the roller gap of the roller mill, the pressure applied in the compression process and / or the number of times the film is compressed. The dry manufacturing process can produce a fibrillated matrix so that the electrode film is self-supporting and / or self-supporting.

[0076] In some embodiments, one or more electrode film mixtures described herein may be combined with one or more other electrode film components and subsequently calendared to form an electrode film. Figure 1One or more electrode films described herein. The electrode films described herein can be used to form anodes and / or cathodes for energy storage devices, for example, batteries, capacitors, capacitor-battery mixtures, fuel cells, combinations thereof, etc. Energy storage devices can be operated with or without lithium. In certain embodiments, the electrode films can be used to manufacture batteries, such as lithium ion batteries or other metal ion batteries. In certain embodiments, the electrode films can be used to manufacture supercapacitors, such as double electric layer capacitors (EDLC). In certain embodiments, the electrode films can be used to manufacture lithium ion capacitors. The electrode films can be self-supporting electrode films provided herein.

[0077] In certain embodiments, the dry electrode film formed by the electrode film mixture provided herein can be suitable for the anode or cathode of energy storage device. For example, the dry electrode film can be coupled to the current collector of the anode or cathode to form a dry electrode, such as by using a lamination process. In certain embodiments, the dry electrode film can be laminated on the current collector. In certain embodiments, lamination is performed at high temperature (e.g., 50-100°C).

[0078] In some embodiments, the dry electrode according to some embodiments can be used for a half-cell. In some embodiments, the half-cell can be formed by using the dry electrode disclosed herein, wherein the metal electrode serves as a counter electrode and a reference electrode. In some embodiments, the metal electrode can be a lithium metal electrode. In some embodiments, the half-cell can also include an electrolyte comprising metal ions of the metal electrode between the dry electrode and the metal electrode. In some embodiments, the capacity of the dry electrode according to some embodiments fully realizes the expected capacity calculated based on the capacity and weight of the active material in the half-cell. In some embodiments, the discharge capacity of the dry electrode according to some embodiments in the half-cell can be or can be about 300mAh / g, 350mAh / g, 400mAh / g, 410mAh / g, 420mAh / g, 450mAh / g, 500mAh / g, 550mAh / g, 600mAh / g, 650mAh / g, 700mAh / g, 750mAh / g, 800mAh / g, 850mAh / g, 900mAh / g, 950mAh / g, or 1000mAh / g, or any range therebetween, for example, from about 300mAh / g to about 1000mAh / g. In some embodiments, the first cycle efficiency (FCE) of the half-cell according to some embodiments can be 80%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 95%, 96%, 97%, 98%, or 99%, or any range therebetween.

[0079] In some embodiments, the electrodes formed herein can be incorporated into energy storage devices, for example, full-cell lithium-ion batteries, such as Figure 1 As shown. In some embodiments, the electrode disclosed herein may be an anode. In some embodiments, the electrode according to some embodiments may be placed in an energy storage device and sealed with a housing. In some embodiments, an electrolyte may be added to the energy storage device and sealed with a housing. In some embodiments, the electrolyte may be a lithium-containing electrolyte including a lithium salt. In general, the lithium salt may include a redox-stable anion. In some embodiments, the anion may be monovalent. In some embodiments, the lithium salt may be selected from hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium bis(trifluoromethanesulfonyl)imide (LiN(SO2CF3)2), lithium trifluoromethanesulfonate (LiSO3CF3), lithium bis(oxalate)borate (LiBOB) and combinations thereof. In some embodiments, the electrolyte may include a quaternary ammonium cation and an anion selected from the group consisting of hexafluorophosphate, tetrafluoroborate and iodide. In some embodiments, the salt concentration is or is 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.

[0080] In some embodiments, the capacity of the lithium ion battery with a dry electrode can 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% in 100 cycles, 200 cycles, 500 cycles, or 1000 cycles or the first cycle thereafter, or any range of values ​​therebetween. In some embodiments, the initial discharge capacity of the 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 the 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%.

[0081] In some embodiments, the energy storage device (e.g., lithium-ion battery) is configured to operate at 2.5 V to 4.5 V or approximately 2.8 V to 4.2 V. In further embodiments, the energy storage device (e.g., lithium-ion battery) may be configured to have a minimum operating voltage of at or about 2.5 V to about 3 V. In yet further embodiments, the energy storage device (e.g., lithium-ion battery) is configured to have a maximum operating voltage of at or about 4.5 V.

[0082] Example

[0083] Example 1: Dry Composite Manufacturing

[0084] Dry composites according to some embodiments were produced. Table 1 summarizes the ingredients of dry composites Nos. 1-4. Other dry composite ingredients can be envisioned and prepared, and the disclosure herein is not limited to the specific ingredients disclosed.

[0085] Table 1

[0086]

[0087] Dry composite material #1 was prepared by first diluting 500 mg of a solution including 0.8 wt % single-walled carbon nanotubes (SWCNT) and 1.2 wt % CMC with 500 mg of water. Then, 40 mg of Si / C composite material and 750 mg of graphite were added to the diluted solution and mixed twice at 800 rpm by a mixer for 365 seconds each to form a slurry. The slurry was then diluted with water to obtain a solid content of 40%, and an overhead mixer was used to obtain a viscosity of less than about 400 cp. The slurry was then spray dried in a spray dryer, wherein the air flow rate was 70 cfm, the inlet temperature was 210°C, and the product temperature was 130°C, the nozzle air pressure was 25 psi, the pump speed was 8 rpm, and the throughput was 45 g / min. The resulting yield was about 60 wt % to about 80 wt %.

[0088] Based on the composition percentages summarized in Table 1 , dry composites #2-3 were fabricated by the same process using different amounts of SWCNT and CMC solutions, graphite, and Si / C composites.

[0089] Dry composite #4 was made by mixing the desired amount of a solution comprising 4.9 wt% polyacrylic acid (PAA) and 0.1 wt% SWCNTs with the desired amount of graphite and Si / C composite according to the ingredients summarized in Table 1. The slurry was then diluted with water using an overhead mixer to obtain a solid content of 40% to obtain a viscosity of less than about 400 cp. The slurry was then spray dried in a spray dryer with an air flow 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 about 60 wt% to about 80 wt%, and was in powder form.

[0090] Table 2 summarizes the median diameter (D50) and percentage of Si / C composite for dry composites #1-4.

[0091] Table 2

[0092]

[0093] The percentage of Si / C composite content was obtained by using thermogravimetric analysis (TGA), and the D50 value was obtained by using a particle size analyzer (PSA). The D50 value increased with the increase in the amount of CNTs. In addition, the D50 value of the dry composite using PAA as a binder was greater than the D50 value of the dry composite using CMC as a binder. The Si / C content was close to the target range of about 5 wt%.

[0094] Example 2: Characterization of dry composites

[0095] Figure 6 The particle size distribution of Dry Composite #2 and Dry Composite #3 is shown. Table 3 summarizes the median diameter (D50) and specific surface area (SSA) of the graphite used to make Dry Composite, Dry Composite #2, and Dry Composite #3. Figure 6 As shown in Table 3, the particle size distribution of dry composite #2 and dry composite #3 did not shift much from the particle size distribution of graphite to larger particle sizes, and the values ​​of the specific surface area of ​​dry composite #2 and dry composite #3 did not change much from the values ​​of the specific surface area of ​​graphite. These experimental results indicate that there is no graphite aggregation in dry composite #2 and dry composite #3.

[0096] Table 3

[0097]

[0098] The morphology of the dry composites was evaluated using scanning electron microscopy (SEM). Fig. 7AShown is a SEM image of a dry composite surface according to some embodiments. Figure 7B yes Figure 7B The enlarged SEM image of the SEM shown. In conventional dry processes, powders of carbon nanotubes and active materials such as graphite and silicon materials can undergo significant aggregation and phase separation because carbon nanotubes have a large surface area. In contrast, Fig. 7A and Figure 7B As shown, the carbon nanotubes form a network across the dry composite material, and the Si / C composite material and graphite are uniformly dispersed in the dry composite material and in contact with the carbon nanotube network.

[0099] Example 3: Fabrication of dry electrodes

[0100] A dry cell anode comprising a dry composite material according to some embodiments is manufactured. In addition to the dry composite material, the dry electrode anode also includes 2 wt % PTFE and 0.5 wt % polyvinylidene fluoride (PVDF). The dry cell membrane is prepared by first mixing PTFE and PVDF with the dry composite material using a non-destructive mixer at 90% and 60 Hz intensity for 5 minutes, followed by higher shear mixing. The obtained powder is calendered at the optimal temperature and gap setting to meet 14-15.2 mg / cm 2 Finally, the dry cell film was calendered on a carbon-coated copper sheet to make a dry cell anode.

[0101] Table 4 summarizes the composition, loading, and density of dry cell anodes made with dry composites #2 and #3.

[0102] Table 4

[0103]

[0104] A conventional dry cell anode without the use of the dry composite material (labeled "control") was also fabricated for comparison with the dry cell anode including the dry composite material. The control electrode was prepared by first directly mixing 92.5 wt % graphite, 5 wt % Si / C composite, 2 wt % PTFE and 0.5 wt % PVDF and then by a dry process.

[0105] The cathode was also manufactured in a dry process, the cathode comprising 97 wt % NMC811, 1 wt % conductive additive and 2 wt % polymer binder.

[0106] Figure 8The half-cell capacity values ​​of dry cell anodes formed of dry composite materials according to some embodiments and without dry composite materials are illustrated. The dry cell anodes formed without dry composite materials are labeled "control". During the half-cell test, the dry cell anode was first discharged to 0.05V with C / 100 hold at C / 20, and then charged to 1V with C / 100 recovery at 25°C.

[0107] like Figure 8 As shown, the first cycle efficiency (FCE) of the dry cell anodes formed from the control anode, dry composite materials #2 and #3 are about 89.7%, 89% and 90.5%, respectively, indicating that the dry cell anodes containing dry composite materials #2 and #3 show improved or at least similar first cycle efficiency compared to the dry anode without dry composite materials. The dry cell anodes formed with dry composite materials #2 and #3 have a capacity of 418 mAh / g and 409.4 mAh / g, respectively, both of which are improved relative to the capacity of the control anode (401.2 mAh / g). In addition, the dry cell anodes using the dry composite materials achieve full utilization of the calculated capacity. In contrast, the dry anodes formed without the dry composite materials do not achieve full utilization of the expected capacity.

[0108] Fig.9A The graph shows the discharge capacity values ​​of dry cell 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 the full cell test was an NMC811 cathode. Fig.9A As shown, the discharge capacity of the dry cell anode containing no CNT, containing 0.25 wt% CNT, containing 0.1 wt% CNT and containing 0.05 wt% CNT is about 199.8 mAh / g, 201.5 mAh / g, 199.4 mAh / g and 201.3 mAh / g, respectively. The first cycle efficiency (FCE) of the dry cell anode containing no CNT, containing 0.25 wt% CNT, containing 0.1 wt% CNT and containing 0.05 wt% CNT is about 88.1%, 87.7%, 88.6% and 86.9%, respectively. Therefore, the capacity of the dry Si / C anode with added carbon nanotubes is improved or similar to the capacity of the dry electrode without added carbon nanotubes. The FCE of the dry anode with added carbon nanotubes is similar to the FCE of the dry electrode without added carbon nanotubes.

[0109] Fig. 9BThe graph shows the cycle life performance of dry cell anodes with no CNTs, 0.25 wt% CNTs, 0.1 wt% CNTs, and 0.05 wt% CNTs in full cell tests. 300 mAh pouch-type full cells were used for the tests. Full cells were assembled with dry NMC811 cathodes. In each cycle, the cell was charged and discharged between 4.2 V and 2.85 V at a rate of C / 20 at 40°C. Fig. 9B As shown, the dry Si / C battery anode with CNTs retains about 95% of its capacity after 100 cycles and has improved capacity retention relative to the dry Si / C battery anode without CNTs.

[0110] Although certain embodiments have been described, these embodiments are presented by way of example only and are not intended to limit the scope of the present disclosure. In fact, the novel methods and systems described herein may be embodied in various other forms. In addition, various omissions, substitutions, and changes may be made to the systems and methods described herein without departing from the spirit of the present disclosure. The attached claims and their equivalents are intended to cover such forms or modifications that fall within the scope and spirit of the present disclosure.

[0111] Features, materials, characteristics or groups described in conjunction 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 incompatible therewith. All features disclosed in this specification (including any 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 embodiments. The protection extends to any novel feature or any novel combination of features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel feature or any novel combination of steps of any method or process so disclosed.

[0112] In addition, certain features described in this disclosure in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented in multiple embodiments individually or in any suitable subcombination. In addition, although features may be described above as functioning in certain combinations, in some cases, one or more features from a claimed combination may be deleted from the combination, and the combination may be claimed as a subcombination or a variation of a subcombination.

[0113] In addition, although the operations may be depicted in a particular order in the drawings or described in a particular order in the specification, such operations need not be performed in the particular order or sequence shown, or all operations need not be performed to achieve the desired result. Other operations not depicted or described may be incorporated into the example methods and processes. For example, one or more additional operations may be performed before, after, simultaneously, or between any of the described operations. In addition, in other embodiments, the operations may be rearranged or reordered. Those skilled in the art will appreciate that in some embodiments, the actual steps taken in the process shown and / or disclosed may be different from those shown in the drawings. Depending on the embodiment, some of the above steps may be deleted, and other steps may be added. In addition, the features and attributes of the specific embodiments disclosed above may be combined in different ways to form additional embodiments, all of which fall within the scope of the present disclosure. In addition, the separation of various system components in the above embodiments should not be understood as requiring such separation in all embodiments, and it should be understood that the components and systems described may generally be integrated together in a single product or packaged into multiple products. For example, any of the components of the energy storage system described herein may be provided separately, or integrated together (e.g., packaged together, or attached together) to form an energy storage system.

[0114] For purposes of the present disclosure, certain aspects, advantages, and novel features are described herein. Not all of these advantages may be achieved according to any particular embodiment. Thus, for example, one skilled in the art will recognize that the present disclosure may be embodied or implemented in a manner that achieves one advantage or group of advantages taught herein without necessarily achieving other advantages taught or suggested herein.

[0115] Conditional language, such as "can," "could," "might," or "may," unless specifically stated otherwise or understood otherwise in the context of use, is generally intended to convey that certain embodiments include, while other embodiments do not, certain features, elements, and / or steps. Thus, such conditional language is generally not intended to imply that one or more embodiments require features, elements, and / or steps in any way, or that one or more embodiments must include logic for deciding, with or without user input or prompting, whether such features, elements, and / or steps are included in any particular embodiment or will be performed.

[0116] Unless expressly stated otherwise, connective language, such as the phrase "at least one of X, Y, and Z," should be understood in context as otherwise generally used to convey that an item, term, etc. may be X, Y, or Z. Thus, such connective language is generally not intended to imply that certain embodiments require the presence of at least one of X, at least one of Y, and at least one of Z.

[0117] As used herein, language of degree, such as the terms "approximately," "about," "generally," and "substantially," as used herein, refers to a value, amount, or characteristic that is close to a stated value, amount, or characteristic and still performs a desired function or achieves a desired result. For example, the terms "approximately," "about," "generally," and "substantially" may refer to an amount that is less than 10%, less than 5%, less than 1%, less than 0.1%, and less than 0.01% of a stated amount, depending on the desired function or desired result.

[0118] The scope of the present disclosure is not intended to be limited by the specific disclosure of preferred embodiments in this section or elsewhere in this specification, but rather may be limited by the claims presented in this section or elsewhere in this specification or by future claims presented. The language of the claims is to be interpreted broadly based on the language used in the claims, and not limited to the examples described in this specification or during the prosecution of the application, which examples are to be construed as non-exclusive.

[0119] 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, the dry composite material comprising: Silicon active materials; Carbon active materials; as well as Carbon additives, The carbon additive, the silicon active material and the carbon active material are substantially uniformly dispersed in the dry composite material.

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

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

4. The dry composite material according to any one of claims 1 to 3, wherein the carbon additive forms a matrix.

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

6. The dry composite material of any one of claims 1 to 5, wherein the dry composite material has a D50 particle size of at least about 16 μm.

7. The dry composite material according to any one of claims 1 to 6, wherein the silicon active material is selected from the group consisting of silicon, silicon derivatives and combinations thereof.

8. The dry composite material according to claim 7, wherein the silicon derivative is selected from silicon oxide SiO x , silicon carbide SiC, silicon carbon composite Si / C and their combination.

9. The dry composite material according to any one of claims 1 to 8, wherein the carbon active material comprises graphite, soft carbon, hard carbon and combinations thereof.

10. The dry composite material according to any one of claims 1 to 9, wherein the dry composite material further comprises a composite binder.

11. The dry composite material according to 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. The dry composite material according to any one of claims 1 to 11, wherein the dry composite material is substantially free of solvent residues.

13. An electrode membrane comprising the dry composite material according to any one of claims 1 to 12. The electrode film according to claim 13 , further comprising a dry binder. 15 . The electrode membrane according to claim 14 , wherein 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.

16. The electrode film according to any one of claims 13 to 15, wherein the electrode film is free-standing and substantially free of solvent residues.

17. An electrode comprising an electrode film according to any one of claims 13 to 16 disposed on a current collector.

18. An energy storage device comprising the electrode according to claim 17.

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

21. A method for preparing a dry composite material for an energy storage device electrode, the method comprising: forming a mixture including a silicon active material, a carbon active material, and a carbon additive; as well as The dry composite material is formed 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 uniformly dispersed throughout the dry composite material.

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

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

24. The method of any one of claims 21 to 23, wherein forming the dry composite material is a process selected from the group consisting of spray drying, tri-kneader mixing, fluidized bed mixing, freeze dry mixing, grinding, mechanical fusion, and combinations thereof.

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

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

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