Electrodes for energy storage devices containing novel binders

Abstract

Disclosed herein is an anode comprising: a current collector; and an anode active layer disposed on the current collector, the anode active layer comprising anode active particles, an anode conductive material, and an anode binder, the anode binder comprising a copolymer comprising a first repeat unit and a second repeat unit, the first repeat unit derived from polymerization of a first monomer comprising an ether linkage or comprising multiple hydroxyl groups, and the second repeat unit derived from polymerization of an ethylenically unsaturated monomer comprising a hydrophilic pendant group.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of U.S. Application No. 63 / 417,207, filed October 18, 2022, which is incorporated herein by reference in its entirety.

[0002] FIELD OF THE INVENTION The present invention relates to energy storage devices, particularly ultracapacitors and lithium ion batteries, and electrodes used therein. [Background technology]

[0003] Lithium batteries are used in many products, including medical devices, electric vehicles, airplanes, and consumer products such as laptop computers, cell phones, and cameras. Due to their high energy density, high operating voltage, and low self-discharge, lithium-ion batteries have overtaken the secondary battery market and continue to find new applications in products and evolving industries.

[0004] Generally, a lithium ion battery ("LIB" or "LiB") includes an anode, a cathode, and an electrolyte material, such as an organic solvent containing a lithium salt. More specifically, the anode and cathode (collectively "electrodes") are formed by mixing either the anode or cathode active material with a binder and a solvent to form a paste or slurry, which is then coated onto a current collector, such as aluminum or copper, and dried to form a film on the current collector. The anode and cathode are then layered or coiled before being housed within a pressurized casing containing the electrolyte material, all of which together form the lithium ion battery.

[0005] The binder serves to adhere the active material to the current collector with a suitable coating. It is important that the binder facilitates maintaining sufficient contact between the active material and the current collector. Furthermore, it was important to select a binder that is mechanically compatible with the electrode active material so that it can withstand the degree of expansion and contraction of the electrode active material during battery charging and discharging. The binder must also be strong enough to withstand the manipulation of the electrode as it is fitted into the battery casing.

[0006] Therefore, binders such as cellulosic binders or cross-linked polymer binders have been used to provide good mechanical properties, however, in conventional electrodes, the binders selected generally require environmentally unfriendly or toxic solvents for processing. Summary of the Invention

[0007] Disclosed herein is an anode comprising: a current collector; and an anode active layer disposed on the current collector, the anode active layer comprising anode active particles, an anode conductive material, and an anode binder, the anode binder comprising a copolymer comprising a first repeat unit and a second repeat unit, the first repeat unit derived from polymerization of a first monomer comprising an ether linkage or comprising multiple hydroxyl groups, and the second repeat unit derived from polymerization of an ethylenically unsaturated monomer comprising a hydrophilic pendant group.

[0008] Also disclosed herein is an energy storage device comprising a housing, an electrolyte, and a first current collector; an anode active material disposed on the first current collector, the anode active material comprising a network of high aspect ratio carbon elements defining void spaces within the network; a plurality of anode active material particles disposed in the void spaces within the network; and an anode polymer binder, the anode binder comprising a copolymer comprising a first repeat unit and a second repeat unit, the first repeat unit comprising an ether linkage or derived from polymerization of a first monomer comprising a plurality of hydroxyl groups. an anode polymer binder, wherein the second repeat unit is derived from the polymerization of an ethylenically unsaturated monomer comprising a hydrophilic pendant group; a second current collector; a cathode active material disposed on the second current collector, the cathode active material comprising a network of high aspect ratio carbon elements defining void spaces within the network; and a plurality of cathode active material particles disposed in the void spaces within the network, the cathode active material comprising a combination of nickel, manganese, and cobalt; a cathode polymer binder, wherein the polymer binder comprises at least one of (i) a polyamide, (ii) a polyamide copolymer, (iii) a polyacrylic acid copolymer, or (iv) a polyacrylate copolymer. [Brief explanation of the drawings]

[0009] The following is a brief description of the drawings, in which like elements are numbered alike and which are presented for the purpose of illustrating, but not for the purpose of limiting, exemplary embodiments disclosed herein. [Figure 1] FIG. 1 is a diagram of an example of an electrode disclosed herein. [Figure 2A] 1 is a flow chart illustrating an example of a method that may be used to fabricate the electrodes disclosed herein. [Figure 2B] 1 is a flowchart illustrating an exemplary method of manufacturing an anode for an energy storage device. [Figure 3] FIG. 1 is a diagram of electrode placement in a pouch cell device. [Figure 4] FIG. 1 is a schematic cross-sectional view illustrating an embodiment of an energy storage device (ESD). [Figure 5] 1 is a graph showing specific energy versus weight percent of lithiated SiOx loading. [Figure 6] 1 is a graph showing specific energy versus cathode mass loading (areal capacity) for different weight percent lithiated SiOx loading. DETAILED DESCRIPTION OF THE INVENTION

[0010] A more complete understanding of the components, processes, and apparatus disclosed herein can be obtained by reference to the accompanying drawings. These figures are merely schematic representations based on convenience and ease of illustrating the disclosure and, as such, are not intended to indicate the relative sizes and dimensions of the devices or their components and / or to define or limit the scope of the exemplary embodiments. Although specific terms are used in the following description for clarity, these terms are intended to refer only to the particular structures of the embodiments selected for illustration in the drawings and are not intended to define or limit the scope of the disclosure. It should be understood that in the drawings and the following description, like numerical designations refer to components of similar function.

[0011] Disclosed herein is an electrolysis cell that includes a housing containing electrodes (anode and cathode). The housing contains an electrolyte in contact with the anode and cathode. Both electrodes (anode and cathode) include current collectors on which an active layer is disposed. The active layer may be disposed on an optional adhesive layer that contacts the electrodes.

[0012] 1 is a diagram of an example of an electrode (anode or cathode) disclosed herein. In the example shown, electrode 100 includes a current collector 102 and an active layer 106. Electrode 100 may optionally include an adhesion layer 104. By way of example, adhesion layer 104 includes a material that promotes adhesion between current collector 102 and active layer 106. Active layer 106 includes electrode active material 110 in a binder and conductive elements 108. The conductive elements may include high aspect ratio elements.

[0013] The current collector 102 is a conductive element. The current collector may include a metal (e.g., a substantially pure metal or a metal alloy). As another example, the current collector 102 may be in the form of a metal strip or foil. For example, the current collector 102 may be an aluminum foil or strip, an aluminum alloy foil or strip, a copper foil or strip, or a copper alloy foil or strip. The current collector 102 may have a thickness of 15 μm (microns) or less, 10 μm or less, 8 μm or less, or 5 μm or less. In some embodiments, the current collector may have a thickness of at least 3 μm. For example, the current collector 102 may have a thickness of 3 to 15 μm, or between 6 μm and about 8 μm. As another example, the current collector 102 is an aluminum foil or aluminum alloy foil having a thickness of 5 to 7 μm.

[0014] The active layer 106 includes a conductive material, a binder material, and an electrode active material. The active layer can be made by mixing the conductive material, binder material, and electrode active material with a solvent to form a mixture. The mixture can be applied directly to the current collector or can be applied onto an adhesive layer to adhere it to the current collector. If an adhesive layer is used, the adhesive layer can be conductive. The mixture can be dried to remove the solvent and leave a solid active layer. The active layers 106 for the anode and cathode will now be described separately.

[0015] anode As indicated above, the anode comprises a conductive element, a binder, and an electrode active material, which are mixed together to form a mixture. The mixture is disposed on a current collector and dried to form an active layer. Each component of the anode active material layer is described in detail below.

[0016] Conductive element The conductive elements (also referred to as conductive materials) may include carbon. For example, the conductive elements may be high aspect ratio carbon elements. The term "high aspect ratio carbon elements" refers to carbonaceous elements having a size in one or more dimensions ("major dimensions") that is significantly larger than the size of the element in a lateral dimension ("minor dimension"). The high aspect ratio carbon elements may include a substantially cylindrical network of carbon atoms. The conductive material may include carbon nanotubes or multiple bundles of carbon nanotubes.

[0017] In embodiments, the conductive material used in the anode may include graphite flakes, as described below.

[0018] The conductive material can form a conductive permeating network capable of transmitting current between any two separated points located on the surface of the solid active layer (without solvent therein). In other words, current can be transmitted from one surface or end of the active layer to the opposite surface or end by physical contact or electron hopping between conductive elements in the electrode active layer. The permeating network can include voids between high-aspect-ratio carbon elements that may contain or house electrode active material. The high-aspect-ratio conductive material can be substantially oriented within the electrode active layer 106 in a direction substantially parallel to the current collector to facilitate current conduction from one end of the electrode to the other while still maintaining less orientation throughout the thickness of the active layer.

[0019] The conductive material may be present in the mixture in an amount of 0.1 to 1.3, or 0.15 to 1.2, or 0.3 to 1 weight percent, based on the total weight of the mixture (the mixture including the conductive material, electrode active material, binder material, and solvent). The conductive material may be present in the active layer in an amount of 0.2 to 3.5, or 0.3 to 3, or 0.5 to 2 weight percent, based on the total weight of solids in the active layer (the total weight of solids including the conductive material, binder material, and electrode active material, excluding solvent).

[0020] The high aspect ratio carbon elements can be single wall carbon nanotubes (SWCNTs), multiwall carbon nanotubes (MWNTs), or a mixture of both.

[0021] The single-walled carbon nanotubes may have an outer diameter of 0.5 to 5.0 nanometers, preferably 1.0 to 3.5 nanometers. The single-walled carbon nanotubes may have an aspect ratio (ratio of length to diameter) greater than about 2.0, preferably greater than 5.0, preferably greater than 10.0, greater than 50, and more preferably greater than 100. In an exemplary embodiment, the single-walled carbon nanotubes may have an average aspect ratio of 5 to 200.

[0022] The single-walled carbon nanotubes may have a length greater than 6 nanometers, preferably greater than 10 nanometers, preferably greater than 15 nanometers, preferably greater than 30 nanometers, preferably greater than 50 nanometers, more preferably greater than 100 nanometers, preferably greater than 1 micrometer, preferably greater than 5 micrometers, preferably greater than 10 micrometers, more preferably greater than 15 micrometers, and up to at least 200 micrometers. In exemplary embodiments, the single-walled carbon nanotubes may have an average length of 10 nanometers to 20 micrometers, preferably 20 nanometers to 15 micrometers.

[0023] The single-walled carbon nanotubes may be present in the mixture of the conductive material, binder material, electrode active material and solvent in an amount of 0.1 to 0.3 wt %, preferably 0.15 to 0.25 wt %, based on the total weight of the mixture.

[0024] The single-walled carbon nanotubes are present in the electrode active layer (the conductive material, binder material, and electrode active material, excluding the solvent) in an amount of 0.2 to 0.6 wt %, preferably 0.3 to 0.5 wt %, based on the total weight of the electrode active layer.

[0025] The number of carbon layers in a multi-walled carbon nanotube can be 2 or more, 5 or more, 10 or more, or 50 or more. A multi-walled carbon nanotube can contain an average of 3 to 15 layers, 4 to 12 layers, 5 to 10 layers, or 6 to 8 layers.

[0026] The active layer 106 may include multi-walled carbon nanotubes and single-walled carbon nanotubes. The multi-walled carbon nanotubes swell more than single-walled carbon nanotubes when wetted by an electrolyte in an energy storage device in which the electrode 100 is located. For example, the multi-walled carbon nanotubes may swell at least 15%, or at least 25%, or at least 50% more than single-walled carbon nanotubes when wetted by an electrolyte in an energy storage device in which the electrode 100 is located. For example, the length of the multi-walled carbon nanotubes may expand at least 15%, or at least 25%, or at least 50% more than the length of single-walled carbon nanotubes when wetted by the electrolyte. In another example, the multi-walled carbon nanotubes swell up to 50% when wetted (e.g., the length of the multi-walled carbon nanotubes increases by 50% after being wetted by the electrolyte and / or the diameter of the multi-walled carbon nanotubes increases by 50% after being wetted, etc.).

[0027] Multi-walled carbon nanotubes can have an outer diameter of 2.0 to 50 nanometers, 5.0 to 40 nanometers, or 6 to 10 nanometers. Multi-walled carbon nanotubes can have lengths greater than 10 nanometers, greater than 15 nanometers, greater than 30 nanometers, greater than 50 nanometers, greater than 100 nanometers, greater than 500 nanometers, greater than 1 micrometer, greater than 5 micrometers, greater than 10 micrometers, or greater than 15 micrometers. At the same time, multi-walled carbon nanotubes can have an average length of up to 25 micrometers or up to 20 micrometers. In exemplary embodiments, multi-walled carbon nanotubes have an average length of 10 nanometers to 20 micrometers or 20 nanometers to 15 micrometers. Multi-walled carbon nanotubes can have an aspect ratio (ratio of length to diameter) greater than 5.0, greater than 10.0, greater than 50, greater than 100, or greater than 500.

[0028] The electrode includes multi-walled carbon nanotubes that may be relatively long compared to multi-walled carbon nanotubes contained in electrodes of the related art. The use of relatively long multi-walled carbon nanotubes in the electrode has been found to have beneficial mechanical and / or electrical properties. For example, multi-walled carbon nanotubes provide relatively good power output at low density. As another example, shorter multi-walled carbon nanotubes generally do not swell (e.g., expand) as much as longer multi-walled carbon nanotubes. Therefore, the use of shorter multi-walled carbon nanotubes loses (or reduces) some of the beneficial properties associated with carbon nanotube swelling. As an extreme example, carbon black does not exhibit swelling because it is merely carbon particles without entanglement (e.g., the entanglement exhibited by a set of multi-walled carbon nanotubes). An indication that a certain amount of multi-walled carbon nanotubes has a length exceeding a threshold length and therefore has sufficient swelling properties is an observation during the calendering process, where a relatively large amount of pressure or effort to calender the slurry in connection with application to the foil indicates that the collective swelling (e.g., average swelling) of the multi-walled carbon nanotubes in the active layer meets a certain performance threshold. However, multi-walled carbon nanotubes are generally difficult to process.

[0029] The processing of multi-walled carbon nanotubes associated with the preparation / formation of the active layer and / or electrode is gentler than processes for related art electrodes. Accordingly, processes according to various embodiments preserve longer multi-walled carbon nanotubes (e.g., fewer multi-walled carbon nanotubes are crushed, fragmented, broken, etc.). In some embodiments, the active layer of the electrode comprises a set of multi-walled carbon nanotubes having an average length longer than the average length of the multi-walled carbon nanotubes in related art electrodes. According to various embodiments, the length distribution of the set of multi-walled carbon nanotubes is skewed relative to the nominal length of the multi-walled carbon nanotubes. In one example, the nominal length of the multi-walled carbon nanotubes is about 16 microns. For example, the multi-walled carbon nanotubes are processed and / or adapted to reduce or minimize crushing or breaking of the multi-walled carbon nanotubes. The lengths of the multi-walled carbon nanotubes in the network of high aspect ratio carbon elements generally are the nominal length of the multi-walled carbon nanotubes, or the lengths of such multi-walled carbon nanotubes tend to be more skewed relative to the nominal length. In some embodiments, at least 75% of the multi-walled carbon nanotubes in the network of high aspect ratio carbon elements are within 10% of their nominal length (e.g., 13.4 microns to about 15 microns). In some embodiments, at least 75% of the multi-walled carbon nanotubes in the network of high aspect ratio carbon elements have a length of at least 12 microns. In some embodiments, at least 75% of the multi-walled carbon nanotubes in the network of high aspect ratio carbon elements have a length of at least 13 microns. In some embodiments, at least 50% of the multi-walled carbon nanotubes in the network of high aspect ratio carbon elements are within 10% of their nominal length (e.g., 13.4 microns to about 15 microns). In some embodiments, at least 50% of the multi-walled carbon nanotubes in the network of high aspect ratio carbon elements have a length of at least 12 microns. In some embodiments, at least 50% of the multi-walled carbon nanotubes in the network of high aspect ratio carbon elements have a length of at least 8 microns.In some embodiments, at least 50% of the multi-walled carbon nanotubes within the network of high aspect ratio carbon elements have a length of at least 13 microns.

[0030] According to various embodiments, the length distribution of the set of multi-walled carbon nanotubes is skewed relative to the nominal length of the multi-walled carbon nanotubes. For example, the multi-walled carbon nanotubes are treated and / or adapted to reduce or minimize fracture or breakage of the multi-walled carbon nanotubes. The lengths of the multi-walled carbon nanotubes in the network of high aspect ratio carbon elements are generally the nominal length of the multi-walled carbon nanotubes, or the lengths of such multi-walled carbon nanotubes tend to be more skewed relative to the nominal length.

[0031] In some embodiments, at least 75% of the multi-walled carbon nanotubes in the network of high aspect ratio carbon elements are within 10% of their nominal length (e.g., between 13.4 micrometers and about 15 micrometers). In some embodiments, at least 75% of the multi-walled carbon nanotubes in the network of high aspect ratio carbon elements have a length of at least 12 micrometers. In some embodiments, at least 75% of the multi-walled carbon nanotubes in the network of high aspect ratio carbon elements have a length of at least 13 micrometers. In some embodiments, at least 50% of the multi-walled carbon nanotubes in the network of high aspect ratio carbon elements are within 10% of their nominal length (e.g., between 13.4 micrometers and about 15 micrometers). In some embodiments, at least 50% of the multi-walled carbon nanotubes in the network of high aspect ratio carbon elements have a length of at least 12 micrometers. In some embodiments, at least 50% of the multi-walled carbon nanotubes in the network of high aspect ratio carbon elements have a length of at least 13 micrometers.

[0032] The multi-walled carbon nanotubes may be present in the mixture (the mixture including the conductive material, the electrode active material, the binder material, and the solvent or combination of solvents) in an amount of 0.3 to 1.0 wt %, preferably 0.4 to 0.9 wt %, based on the total weight of the mixture. The multi-walled carbon nanotubes are present in the solid anode active layer (the solid active layer including the conductive material, the binder material, and the electrode active material, excluding the solvent), in an amount of 0.8 to 2.6 wt %, preferably 1.0 to 1.8 wt %, based on the total weight of the solid anode active layer.

[0033] In instances where both multi-walled and single-walled carbon nanotubes are used, the ratio of the weight of multi-walled carbon nanotubes to the weight of single-walled carbon nanotubes in the mixture or solid active material layer can be at least 2:1.

[0034] In one example, the three-dimensional network of high aspect ratio carbon elements 108 includes carbon nanotubes, which may be multi-walled carbon nanotubes and / or fragments of such carbon nanotubes only.

[0035] In another example, the multi-walled carbon nanotubes are present in the mixture or solid anode active material layer in an amount at least twice the amount of single-walled carbon nanotubes, based on the weight of the conductive material.

[0036] The three-dimensional network of high aspect ratio carbon elements 108 may comprise at least 99% carbon by weight.

[0037] In addition to the high aspect ratio carbon elements (carbon nanotubes), the conductive material may optionally include graphite flakes, carbon black, or a combination thereof.

[0038] The graphite flakes are preferably high aspect ratio graphite flakes, having at least one dimension greater than any other dimension. The graphite flakes may be naturally occurring or commercially synthesized. The graphite flakes may be particulate and ellipsoidal in shape. The aspect ratio of these graphite flakes may range from 2:1 to 20:1, preferably from 5:1 to 12:1. In embodiments, the graphite flakes may be intercalated with metal ions. In another embodiment, the graphite flakes may be exfoliated flakes.

[0039] The graphite flakes may be present in the solid anode active layer (the solid active layer does not contain a solvent and includes a conductive material, a binder material, and an electrode active material) in an amount of 5 to 65 wt %, preferably 8 to 50 wt %, based on the total weight of the solid anode active material.

[0040] In addition to carbon nanotubes, carbon black may also be used. Carbon black typically has a density of 50 square meters per gram (m 2 / gm), preferably 200m 2 / gm, preferably 500m 2 The carbon black is a high surface area carbon black having a surface area greater than 10 ...

[0041] The three-dimensional network of high aspect ratio carbon elements 108 can include an electrically interconnected network of carbon elements that exhibits connectivity above the percolation threshold, where the network defines one or more highly conductive pathways having lengths greater than 100 μm. The percolation threshold is the threshold at which conductive elements contact each other to provide a conductive network measured across any two points on any surface of the network.

[0042] Anode Binder In one embodiment, the anode binder is water-soluble or dispersible in an aqueous solution (e.g., latex). The water-soluble or water-dispersible anode binder comprises a first polymer including a first repeat unit having an ether bond along the chain backbone, and / or comprises a polyol. Polymers having ether bonds along the chain backbone are typically called polyethers and can be used as binders in the active layer in the form of homopolymers, copolymers, or blends with other compatible homopolymers or copolymers.

[0043] In another embodiment, the anode binder can include a first polymer including a first repeat unit comprising a polyol. A polyol is an organic compound containing multiple hydroxyl groups. Polyols containing two, three, and four hydroxyl groups are diols, triols, and tetrols, respectively.

[0044] When the anode binder comprises a copolymer, the first polymer can be covalently or ionically bonded to a second polymer derived from a second repeat unit containing a (meth)acrylic / (meth)acrylate monomer. Other second polymers (which can be used instead of the polymer derived from a (meth)acrylic / (meth)acrylate monomer) are also listed below. The anode binder is desirably water-soluble or soluble in an aqueous solution. In another embodiment, the anode binder is desirably dispersible in water or an aqueous solution.

[0045] The copolymer may be a random copolymer, a block copolymer, an alternating copolymer, a graft copolymer, a star block copolymer, a gradient copolymer, a dendrimer, or a combination thereof. The copolymer may be linear, branched, or crosslinked.

[0046] The polyethers that can be used as binders have the structure of formula (1):

[0047] [ka] In the formula, R1 and R2 may independently be hydrogen or alkyl having 1 to 5 carbon atoms, n is 1 to 4, and m is 50 to 100,000, preferably 200 to 50,000. Examples include polyoxymethylene having the structure of formula (2):

[0048] [ka] Polyethylene oxide having the structure of formula (3)

[0049] [ka] Polytetramethylene oxide having the structure of formula (4)

[0050] [ka] Polypropylene glycol having the structure of formula (5)

[0051] [ka] Polybutylene glycol having the structure of formula (6)

[0052] [ka] or a combination thereof, wherein m has the meaning given above in formula (1). The combination may include blends or copolymers of the foregoing structures.

[0053] As noted above, the binder may include a polyol instead of or in addition to the polyether. Examples of polyols include the polyether polyols shown below.

[0054] [ka] In the formula, n is 50 to 100,000, preferably 100 to 50,000. Blends of the above polyethers and polyols can also be used.

[0055] The first polymer may have a molecular weight of from 1,000 to 1,000,000 grams / mole, preferably from 5,000 to 500,000 grams / mole, as measured using polystyrene standards.

[0056] Other polyols that can be used as binders include polycaprolactone polyols, polyurethanes (obtained by combining a polyol with a polyisocyanate), polycarbonate polyols, and acrylic polyols.

[0057] In embodiments, the polyethers or polyols detailed above may be combined with a second repeat unit derived from the polymerization of a (meth)acrylic / (meth)acrylate to form a copolymer.

[0058] The second repeat unit is derived from the polymerization of an ethylenically unsaturated monomer comprising a hydrophilic pendant group. In embodiments, the hydrophilic pendant group is a carboxylic acid group or a carboxylate salt group. The second repeat unit has a structure derived from the polymerization of a monomer represented by formula (7):

[0059] [ka] where R1 is hydrogen or an alkyl group having 1 to 10 carbon atoms. Carboxylic acids may be neutralized with metal ions (e.g., sodium, zinc, etc.), thus producing polymeric salts (commonly called ionomers). Examples of polymeric acrylics include polyacrylic acid, polymethyl acrylate, polyethyl acrylate, polypropyl acrylate, etc., or combinations comprising at least one of the foregoing acrylates.

[0060] In one embodiment, the second repeat unit is derived from a monomer having a structure represented by formula (8):

[0061] [ka] wherein R1 is hydrogen or an alkyl group having 1 to 10 carbon atoms, and R2 is C 1~10 Alkyl, C 3~10 Cycloalkyl, or C 7~10 It is an aralkyl group. Examples of (meth)acrylates are polymethyl methacrylate, polymethyl ethyl acrylate, polymethyl propyl acrylate, polyethyl ethyl acrylate, polymethyl aryl acrylate, etc., or a combination comprising at least one of the foregoing acrylates. The term "(meth)acrylate" means that either an acrylate or a methacrylate is intended, unless otherwise specified.

[0062] As shown above, acrylics are derived from monomers having at least one fluorine atom substituent and having a structure represented by formula (9):

[0063] [ka] wherein R1 is hydrogen or an alkyl group having 1 to 10 carbon atoms, and R3 is C 2~10It is a fluoroalkyl group. Examples of compounds having the structure of formula (3) are trifluoroethyl methacrylate and dodecafluoroheptyl methacrylate.

[0064] In embodiments, the polyether and / or polyol may be combined with a non-(meth)acrylic / (meth)acrylate second polymer, such as polyacetal, polycarbonate, polyalkyd, polystyrene, polyolefin, polyester, polyamide, polyaramid, polyamideimide, polyarylate, polyurethane, epoxy, phenolic resin, silicone, polyarylsulfone, polyethersulfone, polyphenylene sulfide, polysulfone, polyimide, polyetherimide, polytetrafluoroethylene, polyetherketone, polyetheretherketone, polyetherketoneketone, polybenzoxazole, polyoxadiazole, polybenzothiazinophenothiazine, polybenzothiazole, polypyrazinoquinoxaline, polypyromellitimide, polyginoxaline, polybenzimidazoline, polybenzoquinoxa ... The polymerizable compound may be reacted with a polyisoindole, a polyoxoisoindoline, a polydioxoisoindoline, a polytriazine, a polypyridazine, a polypiperazine, a polypyridine, a polypiperidine, a polytriazole, a polypyrazole, a polycarborane, a polyoxabicyclononane, a polydibenzofuran, a polyphthalide, a polyacetal, a polyanhydride, a polyvinyl ether, a polyvinyl thioether, a polyvinyl alcohol, a polyvinyl ketone, a polyvinyl halide, a polyvinyl nitrile, a polyvinyl ester, a polysulfonate, a polysulfide, a polythioester, a polysulfone, a polysulfonamide, a polyurea, a polyphosphazene, a polysilazane, a polypropylene, a polyethylene, a polyethylene terephthalate, a polyvinylidene fluoride, a polysiloxane, or the like, or a combination thereof.

[0065] The second polymer may have a molecular weight of from 1,000 to 1,000,000 grams / mole, preferably from 5,000 to 500,000 grams / mole, as measured using polystyrene standards.

[0066] Polyethers and / or polyols can be reacted with acrylics / acrylates (or other second polymers listed above) to form water-soluble copolymer binders. In another embodiment, polyethers and / or polyols can be blended with acrylics / acrylates (or other second polymers listed above) to form water-soluble blends.

[0067] When a polyether and / or polyol is reacted with a (meth)acrylic / (meth)acrylate (or other second polymer listed above) to form a copolymer binder, the polyether and / or polyol is present in an amount of 5 to 95 mole percent, preferably 10 to 90 mole percent, and more preferably 20 to 80 mole percent, based on the total number of moles of the copolymer. The poly(meth)acrylic / poly(meth)acrylate (or other second polymer listed above) is present in the copolymer in an amount of 95 to 5 mole percent, preferably 90 to 10 mole percent, and more preferably 80 to 20 mole percent, based on the total number of moles of the copolymer.

[0068] The copolymers can be prepared by known polymerization techniques for ethylenically unsaturated monomers, such as addition, condensation, or ionic polymerization. The polymerization can be, for example, solution or emulsion polymerization.

[0069] If desired, the polymer may contain crosslinkable functional groups or a crosslinking agent may be added to crosslink the binder polymer before fabrication of the electrode active layer is complete.

[0070] When used in the blend, the polyether and / or polyol are present in an amount of 20 to 80 weight percent (wt%), preferably 30 to 70 wt%, based on the total weight of the blend, and the poly(meth)acrylic / poly(meth)acrylate are present in an amount of 80 to 20 wt%, preferably 70 to 30 wt%, based on the total weight of the blend.

[0071] One example of a suitable binder for use in the anode is a water-soluble copolymer of a polyether and polyacrylic acid.

[0072] The water-soluble or water-dispersible binder may be present in the anode mix in an amount of 3 to 12 wt %, based on the total weight of the dry anode active material (solvent absent). The binder may be present in an amount of 5 to 10 wt %, based on the total weight of the dry anode active material (solvent absent).

[0073] Anode Active Material For example, the anode active material may include particles of silicon (Si), germanium (Ge), tin (Sn), lead (Pb), antimony (Sb), bismuth (Bi), zinc (Zn), aluminum (Al), titanium (Ti), nickel (Ni), cobalt (Co), cadmium (Cd); alloys thereof, or alloys of two or more of these, or these with other elements; oxides, carbides, nitrides, sulfides, phosphides, selenides, and tellurides of these metals, and mixtures or lithium-containing complexes thereof; salts and hydroxides of Sn; lithium titanate, lithium manganate, lithium aluminate, lithium-containing titanium oxide, lithium transition metal oxide; prelithiated forms thereof; Li, Li alloys, or surface-stabilized Li having at least 60% lithium by weight, or combinations thereof. The active material may include graphite instead of or in addition to the anode active material. As an example, the anode active material may include silicon oxide and / or silicon carbide. Such anode active materials comprising silicon oxide or silicon carbon oxide may further comprise graphite.

[0074] In embodiments, the active material used in the anode is a lithium-based active material. An example of a lithium-based active material is Li x Si y O zwhere x is 1-15, preferably 2-7, y is 0-4, preferably 1 or 2, and z is 0-9, preferably 1-5. SiO is synthesized by mixing silicon and silica in a 1:1 molar ratio and then sublimating the mixture to collect amorphous SiO (a-SiO) material. Because silicon atoms in a-SiO are randomly distributed, their valences can be 0, 1+, 2+, 3+, and 4+, depending on the number of oxygen atoms bonded to them. Some of the silicon atoms aggregate to form tiny silicon crystals surrounded by other amorphous material with Si-O bonds of different silicon valences. In LIBs, these tiny silicon crystals in a-SiO react with Li+ ions to form Li 15 The silicon dioxide forms Si4 and functions as an active material for storing energy. Because the silicon dioxide is nano-sized, no pulverization is required after lithiation. Therefore, good reversibility can be achieved.

[0075] Examples of lithium-based active materials include Li 15 Examples include Si4, Li2SiO3, Li2Si2O5, Li6Si2O7, Li4SiO4, Li2O, or combinations thereof.

[0076] In embodiments, the lithium-based active material can be blended with a carbonaceous material to form a Li-SiOx-C active material. In other words, the active material can include lithium, silicate, and carbon. Carbon in the form of carbon black, carbon nanotubes, or graphite can be blended with Li. x Si y O z (where x, y, and z values ​​are detailed above) and ground to form aggregates and agglomerates of the Li—SiO x —C active material.

[0077] In producing Li-SiOx-C active material, elemental silicon (Si) can first be reacted and blended with a silicate material (SiOx). The combination of silicon and silica is subjected to a reaction and grinding process to produce a powder. Carbon is added to this powder in a carbon coating process, and lithium is added in a lithium doping process. After the carbon and lithium addition process, the formed Li-SiOx-C material undergoes a classification process to form the final usable anode active material, called Li-SiO with a carbon coating. The relative density of the formed material is approximately 2.1 g / cm at 25°C. 3 It could be.

[0078] In embodiments, the energy storage device may have an initial charge specific capacity of 1500-1600 mAh / g with an initial coulombic efficiency of 90-94%, preferably 1400-1500 mAh / g, and preferably 1350-1400 mAh / g with an initial coulombic efficiency of 87-89%.

[0079] Lithium can be added in elemental form or in the form of a compound. Some of these lithium compounds are listed herein. The D50 particle size of the Li-SiOx-C particles thus prepared is 6-9 micrometers. The BET surface area of ​​the Li-SiOx-C material formed is 3-4 m with a carbon content of 3-4 wt.%, based on the total weight of the Li-SiOx-C active material. 2 The Li / Li of a cell (also called an energy storage device) with a Li-SiOx-C anode can be + The initial charge specific capacity at 5 mV against the Li-SiOx-C anode material may be 1500-1600 mAh / g, and the Li / Li + The initial discharge specific capacity at 2.0 mV against the Li-SiOx-C material may be 1400-1500 mAh / g with an initial coulombic efficiency of 90-94%, and the Li / Li + The initial discharge specific capacity to 1.0 V may be 1350 to 1400 mAh / g with an initial coulombic efficiency of 87 to 89%.

[0080] The preparation of Li-SiOx and Li-SiOx-C active materials, as well as the corresponding electrodes, is described in detail in U.S. Pat. No. 9,825,290 (B2) and U.S. Patent Application No. 2019 / 0237761 (A1), the entire contents of which are incorporated by reference.

[0081] The anode active material may be present in the anode active layer in an amount of 40 to 90 wt %, based on the total weight of the anode active layer (excluding solvent).

[0082] Anode preparation Anodes can be produced by first preparing a mixture (sometimes referred to as a slurry) of conductive elements, active material, and binder in a solvent or solvent mixture. The method used to fabricate the anode can also be used to fabricate the cathode. For the sake of brevity, this method will not be repeated during cathode fabrication. An advantage of the binder as described herein is that a useful slurry can be formed using water, alcohol, or a combination thereof as the solvent. The slurry can then be coated directly onto a current collector or applied to a current collector with an intermediate adhesive layer.

[0083] The slurry can be prepared in a single step. Alternatively, the slurry can be prepared according to a multi-step process such as that shown in the flowchart of FIG. 2A, which illustrates an example process 600 for providing for the electrode 100 of FIG. 1. FIG. 2B shows another manner of manufacturing an anode for an energy storage device. In 610, a conductive material, e.g., high aspect ratio carbon elements, and a surface treatment material (e.g., a surfactant, a binder material as described herein, or both) are combined with a solvent (e.g., water, alcohol, or a combination thereof) to form an initial slurry.

[0084] At 620, the initial slurry is treated to ensure good dispersion of the solid materials in the slurry. This treatment may include introducing mechanical energy into the mixture of solvent and solid materials (e.g., using an ultrasonicator, sometimes referred to as a "sonifier") or other suitable mixing device (e.g., a high-shear mixer). For example, the mechanical energy introduced into the mixture may be at least 0.4 kilowatt-hours per kilogram (kWh / kg), 0.5 kWh / kg, 0.6 kWh / kg, 0.7 kWh / kg, 0.8 kWh / kg, 0.9 kWh / kg, 1.0 kWh / kg, or more. For example, the mechanical energy introduced into the mixture per kilogram of mixture may be in the range of 0.4 kWh / kg to 1.0 kWh / kg, or any subrange thereof, such as 0.4 kWh / kg to 0.6 kWh / kg.

[0085] As an example, an ultrasonic bath mixer can be used. As another example, a probe sonicator can be used. Probe sonication can be significantly more powerful and effective when compared to ultrasonic baths for nanoparticle applications. The high shear forces generated by ultrasonic cavitation have the ability to break down particle agglomerates, resulting in smaller, more uniform particle sizes. Among other things, sonication can result in a stable and homogeneous suspension of solids in a slurry. Generally, this results in the dispersion and deagglomeration and other breakdown of solids. An example of a probe sonication device is the Q Series Probe Sonicator available from QSonica LLC (Newtown, Connecticut). Another example is the Branson Digital SFX-450 sonicator available from Thomas Scientific (Swedesboro, New Jersey).

[0086] The localized nature of each probe within a probe assembly can sometimes result in non-uniform mixing and suspension. This can be the case, for example, with large samples. This can be addressed by using a setup with a continuous flow cell and appropriate mixing. For example, in such a setup, mixing of a slurry achieves a reasonably uniform dispersion.

[0087] The initial slurry, once processed, can have a viscosity in the range of 5,000 cps to 25,000 cps, or any subrange thereof, such as 6,000 cps to 19,000 cps.

[0088] In optional step 630 (e.g., used if no binder was added in step 610), a binder or additional binder may be applied so that a surface treatment may be fully or partially formed on the conductive material (e.g., high aspect ratio carbon elements) in the initial slurry. In some embodiments, the surface treatment may self-assemble at this stage.

[0089] The resulting surface treatment may include functional groups or other features that can promote adhesion between the high aspect ratio carbon elements and the active material particles, as described in further steps below. For example, functional groups on a binder can provide the surface treatment described above.

[0090] At 640, the active material particles can be combined with the initial slurry to form a final slurry containing the active material particles with the high aspect ratio carbon elements having the surface treatment formed thereon.

[0091] The active material may be added directly to the initial slurry. Alternatively, the active material may first be dispersed in a solvent (e.g., water, alcohol, or a combination thereof, using the techniques described above for the initial solvent) to form an active material slurry. This active material slurry can then be combined with the initial slurry to form the final slurry.

[0092] Suitable solvents are water, alcohol, or a combination thereof. Examples of alcohols include ethanol, methanol, propanol, butyl alcohol, ethylene glycol, propylene glycol, or a combination thereof. In addition to water and alcohol, other solvents may be added to facilitate solubilization and / or dispersion of the polymer. Examples of other solvents include polar solvents, nonpolar solvents, etc. The addition of other solvents should preferably not change the solubility of the polymer in water or alcohol. Liquid aprotic polar solvents, such as propylene carbonate, ethylene carbonate, butyrolactone, acetonitrile, benzonitrile, nitromethane, nitrobenzene, sulfolane, dimethylformamide, N-methylpyrrolidone, etc., or combinations thereof, can be added to water or alcohol to dissolve the polymer. Polar protic solvents, such as acetonitrile, nitromethane, acetone, dimethyl sulfoxide, dimethylformamide, etc., or combinations thereof, can also be used. Other nonpolar solvents, such as benzene, toluene, methylene chloride, carbon tetrachloride, hexane, diethyl ether, tetrahydrofuran, etc., or combinations thereof, can also be used. Co-solvents, including at least one aprotic polar solvent and at least one non-polar solvent, can also be utilized to modify the solubilizing power of the solvent.

[0093] When water and alcohol are used as the solvent for the anode active layer (used in the anode), the ratio of water to alcohol is 80:20 to 95:5, preferably 88:12 to 92:8. In an exemplary embodiment, the ratio of water to alcohol is 90:10.

[0094] The solvent may be added to the mixture of binder, conductive material, and active material in an amount of 10 to 1000 wt %, preferably 50 to 500 wt %, and more preferably 100 to 200 wt % of the total weight of the solids used to form the active layer. The solids include materials (e.g., binder, conductive material, and active material) that do not evaporate and become the active material layer disposed on the current conductor.

[0095] At 650, the final slurry is processed to ensure good dispersion of the solid materials in the final slurry. Any suitable mixing process known in the art may be used. For example, this processing may use the techniques described above with reference to 620. Alternatively, a planetary mixer, such as a multi-shaft (e.g., three or more) planetary mixer, may be used. The planetary mixer may feature multiple blades, e.g., two or more mixing blades and one or more (e.g., two, three, or more) dispersion blades, such as a disk dispersion blade.

[0096] During 650, the matrix entangled with the active materials may fully or partially self-assemble as interactions between the surface treatment (eg, binder) and the active materials facilitate the self-assembly process.

[0097] In some embodiments, the final slurry, once processed, has a viscosity in the range of 1,000 cps to 10,000 cps, or any subrange thereof, for example, 2,500 cps to 6000 cps.

[0098] At 660, the active layer 106 is formed from the final slurry. In some embodiments, the final slurry may be wet-cast directly onto the current collector conductive layer 102 (or optional adhesion layer 104) and dried. As an example, casting may form the active layer 106 by applying at least one of heat and high vacuum until substantially all of the solvent and any other liquids are removed. It may be desirable to protect various portions of the underlying layers. For example, protecting the underside of the conductive layer 102 may be desirable if the electrode 100 is intended for single-sided operation. Protection may include, for example, protecting certain areas from the solvent by masking them or providing a drain for removing the solvent.

[0099] In another example, the final slurry can be at least partially dried elsewhere using any suitable technique (e.g., roll-to-roll layer application) and then transferred onto adhesive layer 104 or conductive layer 102 to form active layer 106. As another example, the combined wet slurries can be placed onto an intermediate material having a suitable surface and dried to form a layer (e.g., active layer 106). While any material having a suitable surface can be used as the intermediate material, an exemplary intermediate material includes polytetrafluoroethylene (PTFE) because its properties facilitate its subsequent removal from the surface. Layers can be formed in a press to provide a layer exhibiting a desired thickness, area, and density.

[0100] In yet another example, the final slurry can be formed into a sheet and coated onto the adhesive layer 104 or the conductive layer 102, as appropriate. For example, the final slurry can be applied through a slot die to control the thickness of the applied layer. In another example, the slurry can be applied and then leveled to the desired thickness using, for example, a doctor blade. Various other techniques can be used to apply the slurry. For example, coating techniques can include, but are not limited to, comma coating, comma reverse coating, doctor blade coating, slot die coating, direct gravure coating, air doctor coating (air knife), chamber doctor coating, offset gravure coating, one-roll kiss coating, reverse kiss coating with a small diameter gravure roll, bar coating, three reverse roll coating (top feed), three reverse roll coating (fountain die), reverse roll coating, etc.

[0101] The viscosity of the final slurry can vary depending on the application technique. For example, for comma coating, the viscosity can range from about 1,000 cps to about 200,000 cps. Lip die coating provides coatings with slurries exhibiting viscosities of about 500 cps to about 300,000 cps. Reverse kiss coating provides coatings with slurries exhibiting viscosities of about 5 cps to 1,000 cps. In some applications, each layer can be formed in multiple passes.

[0102] If desired, the active layer 106 formed from the final slurry may be compressed (e.g., using a calendering device) before or after application to the electrode 100. The slurry may be partially or completely dried (e.g., by applying heat, high vacuum, or a combination thereof) before or during the compression process. For example, in some embodiments, the active layer may be compressed to a final thickness (e.g., in a direction perpendicular to the current collector layer 102) that is less than 90%, 80%, 70%, 50%, 40%, 30%, 20%, or 10% or less of its pre-compression thickness.

[0103] If a partially dried layer is formed during the coating or pressing process, the layer may then be completely dried (e.g., by applying heat, high vacuum, or a combination thereof). In some embodiments, substantially all of the solvent is removed from the active layer 106.

[0104] The solvent used to form the slurry is recovered and recycled into the slurry making process.

[0105] The active layer 106 may be compressed, for example, to break down some of the constituent high aspect ratio carbon elements or other carbonaceous materials and increase the surface area of ​​each layer. This compression process may increase one or more of adhesion between the layers, ion transport rates within the layers, and surface area of ​​the layers. In various embodiments, compression may be applied before or after each layer is applied or formed into the electrode 100.

[0106] If calendering is used to compress the active layer 106, the calendering apparatus may be set with a gap spacing equal to 90%, 80%, 70%, 50%, 40%, 30%, less than 20%, or 10% or less of the layer's pre-compression thickness (e.g., set to about 33% of the layer's pre-compression thickness). The calender rolls can be configured to provide a suitable pressure, for example, greater than 1 ton per cm of roll length, greater than 1.5 ton per cm of roll length, greater than 2.0 ton per cm of roll length, greater than 2.5 ton per cm of roll length, or greater. The compressed active layer can have a density in the range of 1 g / cc to 10 g / cc, or any subrange thereof, such as 2.0 g / cc to 4.0 g / cc. Note that the density of the cathode active layer is 2 to 4 g / cc. The anode active layer typically has a density of 1.0 to 1.8 g / cc. The calendering process can be carried out at a temperature ranging from 20° C. to 140° C., or any subrange thereof. In some embodiments, the active layer 106 can be preheated prior to calendering, for example, to a temperature ranging from 20° C. to 100° C., or any subrange thereof.

[0107] The process 600 may include any of the following features (individually or in any suitable combination).

[0108] The initial slurry has a solids content in the range of 0.1% to 20.0% by weight (or any subrange thereof), and / or the final slurry has a solids content in the range of 10.0% to 80% by weight (or any subrange thereof).

[0109] As shown, a scaffold or matrix of conductor and binder can hold the active material particles together to form a cohesive layer that is also strongly attached to a metal current collector. Such active material structures can be created during slurry preparation, followed by a roll-to-roll ("R2R") coating and drying process. One of the main advantages of this technology is its scalability and "drop-in" nature, as various embodiments are compatible with conventional electrode manufacturing processes.

[0110] The matrix can be formed during slurry preparation using the techniques described herein, in which the high-aspect-ratio carbon material is appropriately dispersed and, if desired, chemically functionalized, for example, as described above with reference to process 600 in FIG. 2. The chemical functionalization is designed to form organized self-assembled structures with the surfaces of active material particles, such as NMC particles (discussed in detail below) for use in cathodes, or silicon ("Si") or silicon oxide ("SiO") particles in the case of anodes. The slurries thus formed can be based on water and / or alcohol solvents for cathodes and water for anodes, as such solvents are very easily evaporated and handled during the manufacturing process. Electrostatic interactions promote the self-assembled structure in the slurry, and after the drying process, bonding between the carbon matrix with the thus-formed active material particles and the surface of the current collector is promoted by the surface treatment (e.g., functional groups on the matrix) as well as the strong entanglement of the active material in the carbon matrix.

[0111] The mechanical properties of the electrodes can be modified depending on the application and mass loading requirements by tuning the surface functionalization versus the entanglement effect.

[0112] After coating and drying, the electrode may undergo a calendering step to control the density and porosity of the active material. Densities of 3.5 g / cc or greater and porosities of 20% or greater can be achieved for NMC cathode electrodes. Porosity can be optimized depending on mass loading and lithium-ion battery cell requirements. For silicon oxide or silicon-based anodes, porosity can be specifically controlled to accommodate the expansion of the active material during the lithiation process.

[0113] The teachings herein can provide up to a 20% reduction in $ / kWh. By using water, alcohol, or a water / alcohol mixture as the solvent, these solvents evaporate easily, allowing for higher throughput in electrode production, and more importantly, significantly reducing energy consumption from long dryers. The traditional recovery systems required when using NMP or similar compounds as the solvent are also significantly simplified when using water, alcohol, or a combination thereof.

[0114] The teachings herein provide an active layer with a 3D matrix that can dramatically increase electrode conductivity by 10 to 100 times compared to electrodes using conventional binders such as PVDF, enabling rapid charging at the battery level. This technology enables thick electrode coatings in the cathode, up to 150 μm thick per side (or more) of the current collector. The solvent used in the slurry, combined with the strong 3D carbon matrix, is designed to achieve a thick wet coating without cracking during the drying step. A thick cathode with a high-capacity anode enables a substantial jump in energy density, reaching 400 Wh / kg or more.

[0115] Cathode As indicated above, the cathode comprises a cathode conductive element, a cathode binder, and a cathode active material, which are mixed together to form a mixture. The mixture is disposed on a current collector and dried to form an active layer. Each component of the cathode active material layer is described in detail below.

[0116] Cathode conductive element The cathode conductive element can include carbon nanotubes arranged to form a percolated network containing voids. The cathode active material is located in the voids of the percolated network. The cathode conductive material is similar to that described above for the anode conductive material.

[0117] Cathode binder The cathode includes one or more polymer binders (cathode polymer binders), one or more active materials, and a conductive material. The one or more polymer binders, the one or more active materials, and the conductive material are blended with a solvent to form a cathode mixture. The cathode mixture is then disposed on a current collector (typically metal) and dried to form a solid cathode active layer.

[0118] The cathode polymer binder (used in the cathode) includes a first cathode polymer binder including a polyamide, a polyacrylic acid copolymer, or an acrylate copolymer, and also includes a second cathode polymer binder including polyvinylpyrollidone (PVP).

[0119] The polyamide (used in the first cathode polymer binder) can include aliphatic polyamides, aromatic polyamides, or combinations thereof. In one embodiment, the polyamide includes the general family of resins known as nylons, which are characterized by the presence of amide groups (—C(O)NH—). Any amide-containing polymer can be used individually or in combination. Nylon-6 and nylon-6,6 are suitable polyamide resins available from a variety of commercial sources. However, other polyamides may also be useful, such as nylon-4, nylon-4,6 (PA 46), nylon-12, nylon-6,10, nylon-6,9, nylon-6,12, nylon-9T, copolymers of nylon-6,6 and nylon-6, nylon 610 (PA 610), nylon 11 (PA 11), nylon 12 (PA 12), nylon 6-3-T (PA 6-3-T), polyarylamide (PA MXD 6), polyphthalamide (PPA) and / or polyether block amides, as well as amorphous nylon. Blends of various polyamides, and various polyamide copolymers, may also be useful.

[0120] Polyamides can be obtained by several well-known processes, such as those described in U.S. Patent Nos. 2,071,250, 2,071,251, 2,130,523, 2,130,948, 2,241,322, 2,312,966, and 2,512,606. For example, nylon-6 is a polymerization product of caprolactam. Nylon-6,6 is a condensation product of adipic acid and 1,6-diaminohexane. Similarly, nylon 4,6 is a condensation product of adipic acid and 1,4-diaminobutane. In addition to adipic acid, other diacids useful for preparing nylons include azelaic acid, sebacic acid, dodecanedioic acid, and terephthalic and isophthalic acids. Other useful diamines include, among others, m-xylenediamine, di-(4-aminophenyl)methane, di-(4-aminocyclohexyl)methane; 2,2-di-(4-aminophenyl)propane, 2,2-di-(4-aminocyclohexyl)propane, etc. Copolymers of caprolactam with diacids and diamines are also useful.

[0121] Polyamides are generally derived from the polymerization of organic lactams having from 4 to 12 carbon atoms. In one embodiment, the lactam is represented by formula (I):

[0122] [ka] wherein n is 3 to 11. In one embodiment, the lactam is epsilon-caprolactam, where n is equal to 5.

[0123] Polyamides can also be synthesized from amino acids having 4 to 12 carbon atoms. In one embodiment, the amino acid is represented by formula (II):

[0124] [ka] wherein n is 3 to 11. In one embodiment, the amino acid is epsilon-aminocaproic acid, where n is equal to 5. The polyamide may also be polymerized from an aliphatic dicarboxylic acid having 4 to 12 carbon atoms and an aliphatic diamine having 2 to 12 carbon atoms. In one embodiment, the aliphatic diamine is represented by formula (III): H2N-(CH2) n -NH2(III) wherein n is from about 2 to about 12. In one embodiment, the aliphatic diamine is hexamethylenediamine (H2N(CH2)6NH2). In one embodiment, the molar ratio of dicarboxylic acid to diamine is from 0.66 to 1.5. Within this range, a molar ratio of 0.81 or greater is generally beneficial. In another embodiment, the molar ratio is 0.96 or greater. In yet another embodiment, the molar ratio is 1.22 or less. In yet another embodiment, the molar ratio is 1.04 or less. Examples of polyamides useful in the present invention include nylon 6, nylon 6,6, nylon 4,6, nylon 6,12, nylon 10, or a combination comprising at least one of the foregoing polyamides.

[0125] These copolymers of poly(meth)acrylic acid / poly(meth)acrylate have been listed and described above and will not be repeated here again for the sake of brevity.

[0126] The first cathode polymer binder is present in an amount of 0.1 to 0.4 wt %, preferably 0.15 to 0.375 wt %, based on the weight of the cathode mixture (including the cathode polymer binders (first and second cathode polymer binders), the cathode active material, the cathode conductive material, and the solvent). The first cathode polymer binder is present in the cathode active layer in an amount of 0.2 to 0.5 wt %, preferably 0.25 to 0.45 wt %, based on the total weight of the cathode active layer.

[0127] The cathode active layer includes a second cathode polymer binder including polyvinylpyrrolidone (PVP), which in addition to functioning as the second cathode polymer binder, can also function as a dispersing agent for the cathode active material and the cathode conductive filler.

[0128] The second cathode polymer binder is present in an amount of 0.1 to 0.4 wt %, preferably 0.15 to 0.375 wt %, based on the weight of the cathode mixture (including the cathode polymer binders (first and second cathode polymer binders), the cathode active material, the cathode conductive material, and the solvent). The second cathode polymer binder is present in the cathode active layer in an amount of 0.2 to 0.5 wt %, preferably 0.25 to 0.45 wt %, based on the total weight of the cathode active layer.

[0129] Cathode Active Material The cathode active material can include lithium cobalt oxide (LCO, sometimes called "lithium cobaltate" or "lithium cobaltite"). Examples of LCO formulations include LiCoO, lithium nickel manganese cobalt oxide (NMC, having a formula variant of LiNiMnCo), lithium manganese oxide (LMO, having a formula variant of LiMnO, LiMnO, etc., or combinations thereof), lithium titanate oxide (LTO, one variant of which is LiTiO), and lithium tantalum oxide (LTO). 12 Lithium iron phosphate oxide (LFP, one variant is LiFePO), lithium nickel cobalt aluminum oxide (and its variants as NCA), and other similar materials. Other variants of the foregoing may also be included.

[0130] In embodiments, the cathode active material may include NMC, NCA, NCMA, or a combination thereof.

[0131] When NMC is used as the cathode active material, nickel-rich NMC may be used. For example, a variation of NMC is LiNi x Mn y Co(1-x-y) where x is about 0.7 or more, 0.75 or more, 0.80 or more, 0.85 or more, or more; y is 0.1 or more, 0.15 or more, 0.2 or more, or 0.25 or more; and x + y is less than 1. For example, NMC811 can be used, where x is about 0.8 and y is about 0.1. Alternatively, the cathode active material can be lithium nickel manganese cobalt oxide (LiNi x Mn y Co z O2). Variations of this formula that can be used in the active material layer include NMC111 (discussed in more detail below), NMC532 (LiNi 0.5 Mn 0.3 Co 0.2 O2), NMC622(LiNi 0.6 Mn 0.2 Co 0.2 O2), or a combination thereof.

[0132] In embodiments, NMC91 may be used as the cathode active material. NMC91 contains 91 mole percent or more of nickel. One example of NMC91 is LiNi 0.91 Co 0.06 Mn 0.03 O 2. In addition, the cathode active material is Li[Ni 1-x-y Co x Al y ]O2 (NCA) may also be used. An example of an NCA is NCA89.

[0133] In yet another embodiment, the cathode active material may be an NCMA material. One example of an NCMA is Li[Ni 0.89 Co 0.05 Mn 0.05 Al 0.01 ]O2.

[0134] In embodiments, the cathode active material can also include a nickel-rich combination of nickel, manganese, and cobalt. Lithium-nickel-manganese-cobalt-oxide (LiNiMnCoO), abbreviated as NMC, offers high overall performance, excellent specific energy, and the lowest self-heating rate of all mainstream cathode powders. NMC powder may contain 20-40 wt% nickel, 20-40 wt% manganese, and 20-40 wt% cobalt, based on the total weight of the NMC blend. While the term "NMC powder" can refer to various blends, it is desirable to use a blend containing 33 wt% nickel, 33 wt% manganese, and 33 wt% cobalt. This blend, sometimes referred to as 1-1-1 (NMC111), is useful for frequently cycling applications (automotive, energy storage) due to the reduced material cost resulting from the lower cobalt content of this nickel-rich combination of nickel, manganese, and cobalt (NMC). NMC powders may contain 20-40 wt% nickel, 20-40 wt% manganese, and 20-40 wt% cobalt, based on the total weight of the NMC blend. While the term "NMC powder" can refer to a variety of blends, it is desirable to use a blend containing 33 wt% nickel, 33 wt% manganese, and 33 wt% cobalt. This blend, sometimes referred to as 1-1-1, is useful for applications that use frequent cycling (automotive, energy storage) due to the reduced material cost resulting from the lower cobalt content. Lithium-nickel-manganese-cobalt-oxide (LiNiMnCoO2) offers high overall performance, excellent specific energy, and the lowest self-heating rate of all mainstream cathode powders. Lithium-rich NMC materials, such as 424 and 523 manufactured by BASF, can also be used as cathode active materials.

[0135] In general, increasing the active material loading in the cathode (measured as a function of the total weight of the cathode) increases the areal capacity and specific energy level in the cathode.

[0136] As noted above, the cathode active material can be contained or accommodated in a network of a high aspect ratio conductive material present in the cathode active layer. The cathode active material can be present in the mixture used to form the cathode in an amount of 55 to 75 wt %, preferably 60 to 70 wt %, based on the total weight of the cathode mixture (the mixture used to prepare the cathode active layer, including the cathode binder material, the cathode active material, the cathode conductive material, and the solvent). The cathode active material is present in the cathode active layer (excluding the solvent) in an amount of 95 to 98.5 wt %, based on the total weight of the cathode active layer.

[0137] Fabrication of the cathode active layer The cathode active layer is disposed on a current collector. The cathode active layer is fabricated in a similar manner to the anode active layer. A cathode binder, a cathode active material, and a cathode conductive material are mixed with a solvent to form a slurry. The slurry is disposed on a cathode current collector. The solvent is evaporated, and the cathode current collector may be subjected to further finishing operations on a roll mill to produce a cathode, which may then be used in an energy storage device, as described in more detail below.

[0138] Energy Storage Devices Once the electrode 100 is assembled, it can be used to assemble an energy storage device. Assembly of an energy storage device may follow conventional steps used to assemble an electrode with a separator and place it into a housing, such as a canister or pouch, and may further include additional steps to add electrolyte and seal the housing.

[0139] One exemplary embodiment includes a pouch cell format Li-ion battery energy storage device that combines a Ni-rich NMC active material in the cathode and a SiOx and graphite blend active material in the anode, where both the anode and cathode are fabricated using the 3D carbon matrix process as described herein.

[0140] A schematic diagram of the electrode arrangement of an example pouch cell device is shown in Figure 3. As shown, cathode active layers 760 (e.g., active layers according to various embodiments disclosed herein) on either side of a current collector 710 (e.g., an aluminum foil current collector) form a double-sided cathode disposed between two single-sided anodes. Each single-sided anode has an anode layer 740 or 750 (e.g., an active layer comprising a network of carbon elements as disclosed herein) disposed on a current collector 720 or 730 (e.g., a copper current collector). The electrodes are separated by a permeable separator material 780 wetted by the electrolyte (not shown). This arrangement can be housed within a pouch cell of a type well known in the art.

[0141] 4 shows a cross section of an energy storage device (ESD) 810. The energy storage device (ESD) 810 includes a housing 811. The housing 811 has two terminals 800 disposed on its exterior. The terminals 800 provide an internal electrical connection to a storage cell 812 contained within the housing 811 and an external electrical connection to an external device, such as a filling or charging device (not shown). The energy storage devices disclosed herein can be batteries, capacitors, ultracapacitors, etc. [Example]

[0142] This example is conducted to determine the effect of Li-SiOx-C anode loading on the cathode performance and, therefore, on the cell performance. The cathode loading was between 4.0 and 7.0 mAh / cm. 2The specific energy is determined from the areal capacity (areal capacity). Figure 5 is a graph showing the specific energy versus weight percent of Li-SiOx-C loading. The Li-SiOx-C loading and its effect on the specific energy were measured for loadings ranging from 0 to 95 wt%. From Figure 5, it can be seen that the specific energy increases as the Li-SiOx-C loading goes from 0 wt% to approximately 65 wt% loading. It can also be observed that the specific energy increases with the areal capacity. Figure 6 is a graph showing the specific energy versus cathode mass loading (areal capacity) for different weight percent of Li-SiOx-C loading. Figure 6 shows that increasing the Li-SiOx-C content in the cathode results in an increase in the specific energy (measured in watt-hours per kilogram (Wh / Kg)).

[0143] Table 1 below shows the cell (energy storage device) performance of a cell containing a cathode containing NCM-91 and an anode containing a graphite-SiOx blend (containing 35 wt% graphite and 65 wt% SiOx). The cathode had a density of 3.4-3.6 g / cm. 3 and the anode has a density of 1.45 to 1.60 g / cm 3 It has a density of

[0144] [Table 1]

[0145] As can be seen from Table 1, the cells (also referred to as energy storage devices) exhibit a specific energy of 300-450 watt-hours per kilogram (Wh / kg), preferably 340-400 Wh / kg, and more preferably 360-395 Wh / kg. The cells exhibit an energy density of 900-1000 watt-hours per liter (Wh / L), preferably 930-995 Wh / L, and more preferably 940-990 Wh / L. The initial Coulombic efficiency (ICE) of the cells ranges from 0.87-0.91, preferably 0.89-0.90.

[0146] All ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with respect to each other (e.g., the range "up to 25% by weight, or more specifically, 5% to 20% by weight" includes the endpoints and all intermediate values ​​in the range "5% to 25% by weight", etc.). In addition, the stated upper and lower limits may be combined to form ranges (e.g., "at least 1 or at least 2% by weight" and "up to 10 or 5% by weight" may be combined as the ranges "1 to 10% by weight," or "1 to 5% by weight," or "2 to 10% by weight," or "2 to 5% by weight").

[0147] The present disclosure can alternatively comprise, consist of, or consist essentially of any suitable components disclosed herein. The present disclosure can additionally or alternatively be formulated to be devoid of or substantially free of any component, material, ingredient, adjuvant, or species used in prior art compositions or that is not otherwise necessary to achieve the function and / or purpose of the present disclosure.

[0148] All cited patents, patent applications, and other references are incorporated herein by reference in their entirety. However, if a term in this application contradicts or conflicts with a term in an incorporated reference, the term from this application takes precedence over the conflicting term from the incorporated reference.

[0149] Unless otherwise indicated herein, all test specifications are the latest specifications in effect as of the filing date of this application, or, if priority is claimed, the filing date of the earliest priority application in which the test specifications appear.

Claims

1. an anode, A current collector; an anode active layer disposed on the current collector, the anode active layer comprising anode active particles, an anode conductive material, and an anode binder, the anode binder comprising a copolymer comprising first repeat units and second repeat units, the first repeat units derived from polymerization of a first monomer comprising an ether linkage or comprising multiple hydroxyl groups, and the second repeat units derived from polymerization of an ethylenically unsaturated monomer comprising a hydrophilic pendant group.

2. 10. The anode of claim 1, wherein the hydrophilic pendant groups are carboxylic acid groups or carboxylate salt groups.

3. The anode of claim 1 , wherein the anode conductive elements form a percolated network.

4. The anode of claim 1 , wherein the first monomer further comprises an olefin.

5. The anode of any one of claims 1 to 4, wherein the anode conductive elements comprise a network of high aspect ratio carbon elements.

6. The anode of any one of claims 1 to 5, wherein the high aspect ratio carbon elements comprise carbon nanotubes.

7. The anode of any one of claims 1 to 6, wherein the conductive element further comprises graphite or carbon black.

8. The anode active material has the structure Li ｘ Si ｙ O ｚ 8. The anode of claim 1, comprising a lithium silicate having the formula:

9. 9. The anode of claim 8, wherein x is 2 to 7, y is 1 or 2, and z is 1 to 5.

10. 9. The anode of claim 8, wherein an energy storage device comprising the anode has an initial charge specific capacity of 1500 to 1600 mAh / g.

11. 9. The anode of claim 8 having an initial coulombic efficiency of 87 to 89%.

12. 9. The anode of claim 8, wherein the lithium silicate is present in an amount of 40 to 90 wt %, based on the total weight of the anode active layer.

13. 13. The anode according to claim 1, wherein the anode active layer comprises graphite in an amount of 5 to 60 wt %, based on the total weight of the anode active layer.

14. The anode of claim 8 , wherein the anode active layer further comprises carbon.

15. the network of high aspect ratio carbon elements is a first set of carbon nanotubes, the first set of carbon nanotubes comprising a plurality of first carbon nanotubes or a plurality of bundles of first carbon nanotubes; a second set of carbon nanotubes; the second set of carbon nanotubes comprises a plurality of second carbon nanotubes or a plurality of bundles of second carbon nanotubes; 6. The anode of claim 5, wherein the second set of carbon nanotubes has one or more properties that are different from the first set of carbon nanotubes.

16. 16. The electrode of claim 15, wherein the first set of carbon nanotubes comprises single-walled carbon nanotubes.

17. 16. The electrode of claim 15, wherein the second set of carbon nanotubes comprises multi-walled carbon nanotubes.

18. the first set of carbon nanotubes comprises single-walled carbon nanotubes; the second set of carbon nanotubes comprises multi-walled carbon nanotubes; 16. The electrode of claim 15, wherein the weight ratio of the first set of carbon nanotubes to the second set of carbon nanotubes is between 1:5 and 5:

1.

19. The electrode of claim 5 , wherein the network of high aspect ratio carbon elements comprises a set of multi-walled carbon nanotubes.

20. An energy storage device comprising the anode of any one of claims 1 to 19.

21. A method for making an anode according to any one of claims 1 to 21, comprising the steps of: providing a slurry comprising the anode conductive element, the anode binder, and the anode active material in water, alcohol, or a combination thereof; coating the slurry onto a current collector and drying to remove the solvent.

22. 1. An energy storage device comprising: Housing and Electrolytes, a first current collector; an anode active material disposed on the first current collector, the anode active material comprising a network of high aspect ratio carbon elements defining void spaces within the network; and a plurality of anode active material particles disposed in the void spaces within the network; an anode polymer binder, the anode binder comprising a copolymer including a first repeat unit and a second repeat unit, the first repeat unit derived from polymerization of a first monomer that includes an ether linkage or includes multiple hydroxyl groups, and the second repeat unit derived from polymerization of an ethylenically unsaturated monomer that includes a hydrophilic pendant group; a second current collector; and a cathode active material disposed on the second current collector, the cathode active material comprising a network of high aspect ratio carbon elements, the network of high aspect ratio carbon elements defining void spaces within the network; and a plurality of cathode active material particles disposed in the void spaces within the network, the cathode active material comprising a combination of nickel, manganese, and cobalt; a cathode polymer binder, wherein the polymer binder comprises at least one of (i) a polyamide, (ii) a polyamide copolymer, (iii) a polyacrylic acid copolymer, or (iv) a polyacrylate copolymer.

23. 23. The energy storage device of claim 22, wherein the anode polymer binder further comprises carboxymethyl cellulose.

24. 23. The energy storage device of claim 22, wherein the cathode polymer binder further comprises polyvinylpyrrolidone.

25. 23. The energy storage device of claim 22, wherein the energy storage device exhibits an initial charge specific capacity of 1500 to 1600 mAh / g.

26. 23. The energy storage device of claim 22, wherein the energy storage device exhibits an initial charge specific capacity of 1400-1500 mAh / g with an initial coulombic efficiency of 90-94%.

27. 23. The energy storage device of claim 22, wherein the energy storage device exhibits an initial charge specific capacity of 1350-1400 mAh / g with an initial coulombic efficiency of 87-89%.

28. 23. The energy storage device of claim 22, wherein the energy storage device exhibits a specific energy of 300 to 450 Watt-hours per kilogram (Wh / kg), preferably 340 to 400 Wh / kg, more preferably 360 to 395 Wh / kg.

29. 23. The energy storage device of claim 22, wherein the energy storage device exhibits an energy density of 900 to 1000 Watt-hours per liter (Wh / L), preferably 930 to 995 Wh / L, more preferably 940 to 990 Wh / L.

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