Electrodes for energy storage devices comprising novel binders

Abstract

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

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims the benefit of U.S. Patent Application No. 63 / 417,207, filed on October 18, 2022, which is hereby incorporated by reference in its entirety. Technical Field

[0003] The present invention relates to energy storage devices, particularly supercapacitors and lithium - ion batteries, and electrodes used therein. Background Art

[0004] Lithium batteries are used in many products, including medical devices, electric vehicles, airplanes, and consumer products (such as laptop computers, mobile phones, and cameras). Due to the high energy density, high operating voltage, and low self - discharge of lithium - ion batteries, they have replaced the secondary battery market and continue to find new uses in products and emerging industries.

[0005] 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, a paste or slurry is formed by mixing an anode active material or a cathode active material with a binder and a solvent, and then the paste or slurry is coated on a current collector (such as aluminum or copper) and dried to form a film on the current collector, thereby forming the anode and the cathode (collectively referred to as “electrodes”). Then the anode and the cathode are layered or wound, and then placed in a pressurized housing containing the electrolyte material, and together they form a lithium - ion battery.

[0006] Binders are used to adhere the active materials in a suitable coating to the current collector. Importantly, the binder helps to maintain sufficient contact between the active material and the current collector. Additionally, it is 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 charging and discharging of the battery. The binder must also be sufficient to withstand the manipulation of the electrode during assembly of the electrode into the battery housing.

[0007] Thus, binders such as cellulose binders or cross - linked polymer binders have been used to provide good mechanical properties. However, in conventional electrodes, the binders selected typically require environmentally unfriendly or toxic solvents for processing. Summary of the Invention

[0008] The present disclosure relates to an anode, which includes a current collector; an anodic active layer disposed on the current collector, wherein the anodic active layer contains anodic active particles, anodic conductive material, and anodic binder; wherein the anodic binder contains a copolymer, the copolymer containing a first repeating unit and a second repeating unit; wherein the first repeating unit is derived from the polymerization of a first monomer containing an ether bond or multiple hydroxyl groups, and wherein the second repeating unit is derived from the polymerization of an ethylenically unsaturated monomer containing a hydrophilic side group.

[0009] The present disclosure also relates to an energy storage device, which includes: a housing; an electrolyte; a first current collector; an anodic active material disposed on the first current collector; wherein the anodic active material contains a network of high aspect ratio carbon elements, the high aspect ratio carbon elements defining void spaces within the network; a plurality of anodic active material particles disposed within the void spaces in the network; and an anodic polymer binder, wherein the anodic binder contains a copolymer, the copolymer containing a first repeating unit and a second repeating unit; wherein the first repeating unit is derived from the polymerization of a first monomer containing an ether bond or multiple hydroxyl groups, and wherein the second repeating unit is derived from the polymerization of an ethylenically unsaturated monomer containing a hydrophilic side group; and a second current collector; a cathodic active material disposed on the second current collector; wherein the cathodic active material contains a network of high aspect ratio carbon elements, the high aspect ratio carbon elements defining void spaces within the network; a plurality of cathodic active material particles disposed within the void spaces in the network; wherein the cathodic active material contains a combination of nickel, manganese, and cobalt; and

[0010] a cathodic polymer binder, the polymer binder containing at least one of the following: (i) a polyamide; (ii) a polyamide copolymer; (iii) a polyacrylic acid copolymer; or (iv) a polyacrylate copolymer. Brief Description of the Drawings

[0011] The following is a brief description of the drawings, in which like elements are numbered alike and the drawings are presented for the purpose of illustrating the exemplary embodiments disclosed herein and not for the purpose of limiting the exemplary embodiments.

[0012] Figure 1 is a diagram of an example of an electrode as disclosed herein;

[0013] Figure 2A is a flowchart showing an example of a method that can be used to fabricate an electrode as disclosed herein;

[0014] Figure 2B is a flowchart depicting an exemplary method of manufacturing an anode for an energy storage device;

[0015] Figure 3is a depiction of an electrode arrangement of a pouch cell device;

[0016] Figure 4 is a depiction of a schematic cross - sectional view showing aspects of an energy storage device (ESD);

[0017] Figure 5 is a graph depicting specific energy versus weight percentage of lithiated SiOx loading; and

[0018] Figure 6 is a graph depicting specific energy versus cathode mass loading (areal capacity) for different weight percentages of lithiated SiOx loading. Detailed Description

[0019] A more complete understanding of the components, processes, and devices disclosed herein can be obtained by reference to the accompanying drawings. These drawings are merely schematic representations for convenience and ease of illustration and are therefore not intended to indicate the relative size and dimensions of the device or its 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 structure of the embodiments selected for illustration in the drawings and are not intended to define or limit the scope of the disclosure. In the drawings and the following description, it should be understood that like reference numerals denote components of like function.

[0020] Disclosed herein is an electrolyte cell including a housing that includes electrodes (an anode and a cathode). The housing includes an electrolyte that contacts the anode and the cathode. Both electrodes (the anode and the cathode) include current collectors having active layers disposed thereon. The active layer may be disposed on an optional adhesion layer that contacts the electrode.

[0021] Figure 1 is a diagram of an example of an electrode (anode and cathode) as disclosed herein. In the example shown, electrode 100 includes current collector 102 and active layer 106. Electrode 100 may optionally include adhesion layer 104. As an example, adhesion layer 104 includes a material that promotes adhesion between current collector 102 and active layer 106. Active layer 106 contains electrode active material 110 and conductive elements 108 in a binder. The conductive elements may include high aspect ratio elements.

[0022] The current collector 102 is a conductive element. The current collector can include a metal (e.g., a substantially pure metal or a metal alloy, etc.). As another example, the current collector 102 can be in the form of a metal strip or a metal foil. For example, the current collector 102 can be an aluminum foil or an aluminum strip, an aluminum alloy foil or an aluminum alloy strip, a copper foil or a copper strip, or a copper alloy foil or a copper alloy strip. The current collector 102 can have a thickness of no more than 15 μm (micrometers), no more than 10 μm, no more than 8 μm, or no more than 5 μm. In some embodiments, while the current collector can have a thickness of at least 3 μm. For example, the current collector 102 can have a thickness of 3 μm to 15 μm or 6 μm to about 8 μm. As another example, the current collector 102 is an aluminum foil or an aluminum alloy foil having a thickness of 5 μm to 7 μm.

[0023] The active layer 106 includes a conductive material, a binder material, and an electrode active material. The active layer can be manufactured by mixing the conductive material, the binder material, and the electrode active material with a solvent to form a mixture. The mixture can be applied directly to the current collector or to an adhesion layer that can adhere to the current collector. If an adhesion layer is used, it can be conductive. The mixture can be dried to remove the solvent, leaving a solid active layer. The active layer 106 for the anode and the cathode will now be described in detail separately.

[0024] Anode

[0025] As described above, the anode includes a conductive element, a binder, and an electrode active material that are mixed together to form a mixture. The mixture is disposed on the current collector and dried to form the active layer. The various components of the anode active material layer are described in detail below.

[0026] Conductive element

[0027] The conductive element (also referred to as the conductive material) can include carbon. For example, the conductive element can be a high aspect ratio carbon element. The term "high aspect ratio carbon element" refers to a carbon-containing element whose dimensions in one or more dimensions ("major dimensions") are significantly larger than the dimensions of the element in the transverse dimension ("minor dimensions"). The high aspect ratio carbon element can include a substantially cylindrical network of carbon atoms. The conductive material can include carbon nanotubes or multi-bundles of first carbon nanotubes.

[0028] In one embodiment, the conductive material used in the anode can include graphite flakes. This will be described later.

[0029] The conductive material can form a conductive percolation network that can conduct current between any two separate points on the surface of a solid active layer (where there is no solvent). In other words, by means of physical contact or electron hopping between the conductive elements in the electrode active layer, current can be transmitted from one surface or end of the active layer to the opposite surface or end. The percolation network can include voids between high aspect ratio carbon elements that can contain or accommodate the electrode active material. The high aspect ratio conductive material can be oriented substantially in the direction parallel to the current collector in the electrode active layer 106 to facilitate the conduction of current from one end of the electrode to the other end, while also maintaining some minor orientation across the thickness of the active layer.

[0030] Based on the total weight of the mixture (the mixture contains a conductive material, an electrode active material, a binder material, and a solvent), the conductive material can be present in the mixture in an amount of 0.1 wt% to 1.3 wt%, or 0.15 wt% to 1.2 wt%, or 0.3 wt% to 1 wt%. Based on the total weight of the solids in the active layer (the total weight of the solids includes the conductive material, the binder material, and the electrode active material, excluding the solvent), the conductive material can be present in the active layer in an amount of 0.2 wt% to 3.5 wt%, or 0.3 wt% to 3 wt%, or 0.5 wt% to 2 wt%.

[0031] The high aspect ratio carbon elements can be single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWNTs), or a mixture of both.

[0032] Single-walled carbon nanotubes can have an outer diameter of 0.5 nanometers to 5.0 nanometers, preferably 1.0 nanometers to 3.5 nanometers. Single-walled carbon nanotubes can have an aspect ratio (length to diameter ratio) greater than about 2.0, preferably greater than 5.0, preferably greater than 10.0, greater than 50, and even more preferably greater than 100. In one exemplary embodiment, single-walled carbon nanotubes can have an average aspect ratio of 5 to 200.

[0033] Single-walled carbon nanotubes can 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, and even more preferably greater than 15 micrometers up to at least 200 micrometers. In one exemplary embodiment, single-walled carbon nanotubes can have an average length of 10 nanometers to 20 micrometers, preferably 20 nanometers to 15 micrometers.

[0034] Based on the total weight of the mixture of the conductive material, the binder material, the electrode active material, and the solvent, single-walled carbon nanotubes can be present in the mixture in an amount of 0.1 wt% to 0.3 wt%, preferably 0.15 wt% to 0.25 wt%.

[0035] Based on the total weight of the electrode active layer (conductive material, binder material, and electrode active material, without solvent), single-walled carbon nanotubes are present in the electrode active layer in an amount of 0.2 wt% to 0.6 wt%, preferably 0.3 wt% to 0.5 wt%.

[0036] The number of carbon walls in the multi-walled carbon nanotubes can be 2 or more, 5 or more, 10 or more, 50 or more. The multi-walled carbon nanotubes can include an average of 3 to 15 layers, 4 to 12 layers, 5 to 10 layers, 6 to 8 layers.

[0037] The active layer 106 can include multi-walled carbon nanotubes and single-walled carbon nanotubes. When the multi-walled carbon nanotubes and single-walled carbon nanotubes are wetted by the electrolyte in the energy storage device having the electrode 100, the multi-walled carbon nanotubes swell more than the single-walled carbon nanotubes. For example, when the multi-walled carbon nanotubes and single-walled carbon nanotubes are wetted by the electrolyte in the energy storage device in which the electrode 100 is located, the multi-walled carbon nanotubes can swell at least 15%, or at least 25%, or at least 50% more than the single-walled carbon nanotubes. For example, when the multi-walled carbon nanotubes and single-walled carbon nanotubes are wetted by the electrolyte, the length of the multi-walled carbon nanotubes expands at least 15%, or at least 25%, or at least 50% more than the length of the single-walled carbon nanotubes. As another example, the multi-walled carbon nanotubes swell up to 50% when wetted (e.g., the length of the multi-walled carbon nanotubes is 50% greater after being wetted by the electrolyte, and / or the diameter of the multi-walled carbon nanotubes is 50% greater after wetting, etc.).

[0038] The multi-walled carbon nanotubes can have an outer diameter of 2.0 nm to 50 nm, 5.0 nm to 40 nm, or 6 nm to 10 nm. The multi-walled carbon nanotubes can have a length greater than 10 nm, greater than 15 nm, greater than 30 nm, greater than 50 nm, greater than 100 nm, greater than 500 nm, greater than 1 μm, greater than 5 μm, greater than 10 μm, or greater than 15 μm. At the same time, the multi-walled carbon nanotubes can have an average length of up to 25 μm or up to 20 μm. In an exemplary embodiment, the multi-walled carbon nanotubes have an average length of 10 nm to 20 μm or 20 nm to 15 μm. The multi-walled carbon nanotubes can have an aspect ratio (length to diameter ratio) greater than 5.0, greater than 10.0, greater than 50, greater than 100, or greater than 500.

[0039] The electrode includes multi-walled carbon nanotubes that can be relatively long compared to the multi-walled carbon nanotubes included in related art electrodes. 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 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. Thus, 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 carbon black is merely particles of carbon without entanglement, such as the entanglement exhibited by a group of multi-walled carbon nanotubes. An indication that a quantity of multi-walled carbon nanotubes has a length exceeding a threshold length and thus has sufficient swelling properties is an observation during a calendering process - the calendering of a relatively large amount of pressure or effort applied to the slurry related to the foil indicates that the total swelling (e.g., average swelling) of the multi-walled carbon nanotubes in the active layer will meet a specific performance threshold. However, multi-walled carbon nanotubes are generally difficult to process.

[0040] The processing of multi-walled carbon nanotubes related to the preparation / formation of the active layer and / or the electrode is milder than the processes for electrodes in the related art. Accordingly, longer multi-walled carbon nanotubes are maintained in the processes according to various embodiments (e.g., fewer multi-walled carbon nanotubes are crushed, broken, fractured, etc.). In some embodiments, the active layer of the electrode comprises a set of multi-walled carbon nanotubes having an average length greater than the average length of the multi-walled carbon nanotubes in electrodes of the related art. According to various embodiments, the length distribution of the set of multi-walled carbon nanotubes is skewed towards multi-walled carbon nanotubes of a nominal length. By way of 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 applied in a manner that reduces or minimizes the breakage or fracture of the multi-walled carbon nanotubes. The length of the multi-walled carbon nanotubes in the network of high aspect ratio carbon elements is typically the nominal length of the multi-walled carbon nanotubes, or the length of such multi-walled carbon nanotubes tends to be more severely skewed towards the nominal length. In some embodiments, at least 75% of the multi-walled carbon nanotubes within the network of high aspect ratio carbon elements are within 10% of the nominal length (e.g., between 13.4 microns and about 15 microns). In some embodiments, at least 75% of the multi-walled carbon nanotubes within 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 within 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 within the network of high aspect ratio carbon elements are within 10% of the nominal length (e.g., between 13.4 microns and about 15 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 12 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 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.

[0041] According to various embodiments, the length distribution of the set of multi-walled carbon nanotubes is skewed towards multi-walled carbon nanotubes of a nominal length. For example, the multi-walled carbon nanotubes are processed and / or applied in a manner that reduces or minimizes the breakage or fracture of the multi-walled carbon nanotubes. The length of the multi-walled carbon nanotubes in the network of high aspect ratio carbon elements is typically the nominal length of the multi-walled carbon nanotubes, or the length of such multi-walled carbon nanotubes tends to be more severely skewed towards the nominal length.

[0042] In some embodiments, at least 75% of the multi-walled carbon nanotubes within the network of the high aspect ratio carbon element are within 10% of the nominal length (e.g., between 13.4 microns and about 15 microns). In some embodiments, at least 75% of the multi-walled carbon nanotubes within the network of the high aspect ratio carbon element have a length of at least 12 microns. In some embodiments, at least 75% of the multi-walled carbon nanotubes within the network of the high aspect ratio carbon element have a length of at least 13 microns. In some embodiments, at least 50% of the multi-walled carbon nanotubes within the network of the high aspect ratio carbon element are within 10% of the nominal length (e.g., between 13.4 microns and about 15 microns). In some embodiments, at least 50% of the multi-walled carbon nanotubes within the network of the high aspect ratio carbon element have a length of at least 12 microns. In some embodiments, at least 50% of the multi-walled carbon nanotubes within the network of the high aspect ratio carbon element have a length of at least 13 microns.

[0043] Based on the total weight of the mixture (which comprises a conductive material, an electrode active material, a binder material, and a solvent or combination of solvents), the multi-walled carbon nanotubes may be present in the mixture in an amount of from 0.3 wt% to 1.0 wt%, preferably from 0.4 wt% to 0.9 wt%. Based on the total weight of the solid anode active material, the multi-walled carbon nanotubes are present in the solid anode active layer (the solid active layer comprises a conductive material, a binder material, an electrode active material, and no solvent) in an amount of from 0.8 wt% to 2.6 wt%, preferably from 1.0 wt% to 1.8 wt%.

[0044] In an example where both multi-walled carbon nanotubes and single-walled carbon nanotubes are used, the ratio of the weight of the multi-walled carbon nanotubes to the weight of the single-walled carbon nanotubes in the mixture or in the solid active material layer may be at least 2:1.

[0045] In one example, the three-dimensional network of the high aspect ratio carbon element 108 comprises carbon nanotubes, and the carbon nanotubes are only multi-walled carbon nanotubes and / or fragments of such carbon nanotubes.

[0046] In another example, based on the weight of the conductive material, the multi-walled carbon nanotubes are present in the mixture or in the solid anode active material layer in an amount that is at least twice the amount of the single-walled carbon nanotubes.

[0047] The network of the three-dimensional network of the high aspect ratio carbon element 108 may comprise at least 99 wt% carbon.

[0048] In addition to the high aspect ratio carbon element (carbon nanotubes), the conductive material may optionally comprise graphite flakes, carbon black, or a combination thereof.

[0049] The graphite flakes are preferably high aspect ratio graphite flakes, where at least one dimension is greater than any other dimension. The graphite flakes can be naturally occurring or commercially synthesized flakes. The graphite flakes are particulate and can be oval in shape. The aspect ratio of these graphite flakes can range from 2:1 to 20:1, preferably from 5:1 to 12:1. In one embodiment, the graphite flakes can be embedded with metal ions. In another embodiment, the graphite flakes can be exfoliated flakes.

[0050] Based on the total weight of the solid anode active material, the graphite flakes can be present in the solid anode active layer (the solid active layer contains a conductive material, a binder material, and an electrode active material, and does not contain a solvent) in an amount of 5 wt% to 65 wt%, preferably 8 wt% to 50 wt%.

[0051] In addition to carbon nanotubes, carbon black can also be used. Carbon black typically has a surface area greater than 50 square meters per gram (m 2 / gm), preferably greater than 200 m 2 / gm, and more preferably greater than 500 m 2 / gm of high surface area carbon black. An example of high surface area carbon black is KELTJEN Black. Carbon black is optional and can be present in the solid anode active layer (the solid active layer contains a conductive material, a binder material, and an electrode active material, and does not contain a solvent) in an amount of 0.5 wt% to 2.0 wt%, preferably 0.8 wt% to 1.6 wt%, based on the total weight of the solid anode active material.

[0052] The three-dimensional network of the high aspect ratio carbon element 108 can include an electrical interconnect network of carbon elements that exhibits connectivity above the percolation threshold, and where the network defines one or more highly conductive pathways having a length greater than 100 μm. The percolation threshold is the threshold at which conductive elements contact each other to provide a conductive network measured between any two points on any surface across the network.

[0053] Anode adhesive

[0054] In one embodiment, the anode binder is water-soluble or dispersible in an aqueous solution (such as a latex). The water-soluble or water-dispersible anode binder contains a first polymer that contains a first repeating unit that contains an ether bond along the main chain and / or contains a polyol. Polymers having an ether bond along the main chain are generally referred to as polyethers and can be used as binders in the active layer in the form of a homopolymer, a copolymer, or a blend with other compatible homopolymers or copolymers.

[0055] In another embodiment, the anode binder may comprise a first polymer, the first polymer comprising a first repeating unit, the first repeating 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 tetraols, respectively.

[0056] When the anode binder comprises a copolymer, the first polymer may be covalently or ionically bonded to a second polymer derived from a second repeating unit comprising (meth)acrylic acid / (meth)acrylate monomers. Other second polymers (which may be used in place of the polymer derived from (meth)acrylic acid / (meth)acrylate monomers) are also listed below. It is desirable that the anode binder is water-soluble or soluble in an aqueous solution. In another embodiment, it is desirable that the anode binder is dispersible in water or an aqueous solution.

[0057] The copolymer may be a random copolymer, block copolymer, alternating copolymer, graft copolymer, star block copolymer, gradient copolymer, dendrimer, or a combination thereof. The copolymer may be a linear polymer, a branched polymer, or may be crosslinked.

[0058] The polyether that can be used as a binder has the structure of formula (1):

[0059]

[0060] wherein R1 and R2 may independently be hydrogen or an alkyl group having 1 to 5 carbon atoms, n is 1 to 4, m is 50 to 100,000, preferably 200 to 50,000. Examples include polyformaldehyde having the structure of formula (2):

[0061]

[0062] Polyethylene oxide having the structure of formula (3)

[0063]

[0064] Polyoxytetramethylene having the structure of formula (4)

[0065]

[0066] Polypropylene glycol having the structure of formula (5)

[0067]

[0068] Polybutylene glycol having the structure of formula (6)

[0069] or a combination thereof, wherein m has the meaning shown in formula (1) above. The combination may include blends or copolymers of the foregoing structures.

[0070] As described above, instead of or in addition to the polyether, the binder may comprise a polyol. Examples of polyols include the polyether polyols shown below.

[0071] Poly(ethylene glycol glutarate)

[0072] Poly(ethylene glycol adipate)

[0073] Poly(ethylene glycol azelate)

[0074] Poly(1,3-propanediol glutarate)

[0075] where n is from 50 to 100,000, preferably from 100 to 50,000. Blends of the above polyethers and polyols may also be used.

[0076] The first polymer may have a molecular weight of from 1,000 g / mol to 1,000,000 g / mol, preferably from 5,000 g / mol to 500,000 g / mol, measured using polystyrene standards.

[0077] Other polyols that can be used as binders include polycaprolactone polyols, polyurethanes (obtained by combining polyols with polyisocyanates), polycarbonate polyols, and acrylic polyols.

[0078] In one embodiment, the polyethers or polyols detailed above may be combined with a second repeating unit derived from the polymerization of (meth)acrylic acids / (meth)acrylates to form a copolymer.

[0079] The second repeating unit is derived from the polymerization of an ethylenically unsaturated monomer comprising a hydrophilic side group. In one embodiment, the hydrophilic side group is a carboxylic acid group or a carboxylate group. The second repeating unit has a structure derived from the polymerization of a monomer represented by formula (7):

[0080]

[0081] where R1 is hydrogen or an alkyl group having 1 to 10 carbon atoms. The carboxylic acid can be neutralized with a metal ion (e.g., sodium, zinc, etc.) to produce a polymer salt (commonly referred to as an ionomer). Examples of polymerized acrylic acids include polyacrylic acid, polymethacrylate, polyethyl acrylate, polypropyl acrylate, etc., or combinations comprising at least one of the foregoing acrylates.

[0082] In one embodiment, the second repeating unit is derived from a monomer having the structure represented by formula (8):

[0083]

[0084] 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 Aralkyl groups. Examples of (meth)acrylates are polymethyl methacrylate, polyethyl methacrylate, polypropyl methacrylate, polyethyl acrylate, polymethyl aryl acrylate, and the like, or a combination comprising at least one of the foregoing acrylates. Unless otherwise indicated, the term "(meth)acrylate" is meant to encompass either acrylate or methacrylate.

[0085] As described above, acrylic acid is derived from a monomer having at least one fluorine atom substituent and having a structure represented by formula (9):

[0086]

[0087] wherein R1 is hydrogen or an alkyl group having 1 to 10 carbon atoms, and R3 is C 2-10 Fluoroalkyl group. Examples of the compound having the structure of formula (3) are trifluoroethyl methacrylate and dodecafluoroheptyl methacrylate.

[0088] In one embodiment, the polyether and / or polyol may be reacted with a non-(meth)acrylic / (meth)acrylate second polymer such as a polyacetal, polycarbonate, polyester resin, polystyrene, polyolefin, polyester, polyamide, aromatic polyamide, polyamideimide, polyarylate, polyurethane, epoxide, phenolic, siloxane, polyarylsulfone, polyethersulfone, polyphenylene sulfide, polysulfone, polyimide, polyetherimide, polytetrafluoroethylene, polyetherketone, polyetheretherketone, polyetherketoneketone, polybenzoxazole, polyoxadiazole, polybenzothiazin and phenothiazine, polybenzothiazole, polypyrazinoquinoxaline, polypyromellitic tetracarboxamide, polyisocyanate ... amine, polyquinoxaline, polybenzimidazole, polyoxyindole, polyoxyisoindoline, polydioxyisoindoline, polytriazine, polypyridazine, polypiperazine, polypyridine, polypiperidine, polytriazole, polypyrazole, polycarborane, polyoxabicyclononane, polydibenzofuran, polyphthalamide, polyacetal, polyanhydride, polyvinyl ether, polyvinyl sulfide, polyvinyl alcohol, polyvinyl ketone, polyvinyl halide, polyvinyl nitrile, polyvinyl ester, polysulfonate, polysulfide, polythioester, polysulfone, polysulfone, polysulfonamide, polyurea, polyphosphazene, polysilazane, polypropylene, polyethylene, polyethylene terephthalate, polyvinylidene fluoride, polysiloxane, etc., or a combination thereof.

[0089] The second polymer can have a molecular weight of 1,000 to 1,000,000 g / mole, preferably 5,000 to 500,000 g / mole, as measured using polystyrene standards.

[0090] The polyether and / or polyol can react with acrylic acid / acrylates (or other second polymers listed above) to form a water-soluble copolymer binder. In another embodiment, the polyether and / or polyol can be blended with acrylic acid / acrylates (or other second polymers listed above) to form a water-soluble blend.

[0091] When the polyether and / or polyol reacts with (meth)acrylic acid / (meth)acrylates (or other second polymers listed above) to form a copolymer binder, the polyether and / or polyol is present in an amount of 5 mol% to 95 mol%, preferably 10 mol% to 90 mol%, and more preferably 20 mol% to 80 mol% based on the total moles of the copolymer. Based on the total moles of the copolymer, poly(meth)acrylic acid / poly(meth)acrylates (or other second polymers listed above) is present in the copolymer in an amount of 95 mol% to 5 mol%, preferably 90 mol% to 10 mol%, and more preferably 80 mol% to 20 mol%.

[0092] The copolymer can be manufactured by known polymerization techniques for ethylenically unsaturated monomers - such as addition polymerization, condensation polymerization, or ionic polymerization. The polymerization can be, for example, solution polymerization or emulsion polymerization.

[0093] If desired, the polymer can contain crosslinking functional groups, or a crosslinking agent can be added such that the binder polymer can be crosslinked before the production of the electrode active layer is completed.

[0094] When used in a blend, the polyether and / or polyol is present in an amount of 20 wt% to 80 wt% (wt%), preferably 30 wt% to 70 wt% based on the total weight of the blend. Based on the total weight of the blend, poly(meth)acrylic acid / poly(meth)acrylates is present in an amount of 80 wt% to 20 wt%, preferably 70 wt% to 30 wt%.

[0095] An example of a suitable binder for the anode is a water-soluble copolymer of polyether and polyacrylic acid.

[0096] Based on the total weight of the dry anode active material (solvent-free), the water-soluble or water-dispersible binder can be present in the anode mixture in an amount of 3 wt% to 12 wt%. Based on the total weight of the dry anode active material (solvent-free), the binder can be present in an amount of 5 wt% to 10 wt%.

[0097] Anode active material

[0098] For example, the anode active material may include 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 of two or more of them or alloys of them with other elements; oxides, carbides, nitrides, sulfides, phosphides, selenides, and tellurides of these metals and their mixtures or lithium-containing composites; salts and hydroxides of Sn; lithium titanate, lithium manganate, lithium aluminate, lithium-containing titanium oxides, lithium transition metal oxides; their pre-lithiated forms; particles of Li, Li alloys or surface-stabilized Li having at least 60 wt% lithium, or combinations thereof. Instead of or in addition to the anode active material, the active material may include graphite. As an example, the anode active material may include silicon oxide and / or carbon silicon oxide. Such an anode active material containing silicon oxide or carbon silicon oxide may further include graphite.

[0099] In one embodiment, the active material for use in the anode is a lithium-based active material. Examples of lithium-based active materials are Li x Si y O z , where x is from 1 to 15, preferably from 2 to 7, y is from 0 to 4, preferably 1 or 2, and z is from 0 to 9, preferably from 1 to 5. SiO is synthesized by mixing silicon and silicon dioxide in a 1:1 molar ratio and then subliming the mixture to collect amorphous SiO (a-SiO) material. Since the silicon atoms in a-SiO are randomly distributed, their valence numbers can be 0, 1+, 2+, 3+, and 4+ under bonding conditions with different numbers of oxygen atoms. Some silicon atoms aggregate and form tiny silicon crystals surrounded by other amorphous substances, where the Si-O bonds have different silicon valence numbers. In a LIB, these tiny silicon crystals in a-SiO react with Li+ ions and form Li 15 Si4, as the active material for storing energy. Due to the nanoscale of the tiny silicon crystals, no pulverization occurs after lithiation; thus, good reversibility can be obtained.

[0100] Examples of lithium-based active materials include Li 15 Si4, Li2SiO3, Li2Si2O5, Li6Si2O7, Li4SiO4, Li2O, or combinations thereof.

[0101] In one embodiment, the lithium-based active material may be blended with a carbonaceous material to form a Li-SiOx-C active material. In other words, the active material may include lithium, silicate, and carbon. Carbon in the form of carbon black, carbon nanotubes, or graphite may be combined with Li x Si y O z(where the x, y, and z values are detailed above) are blended and pulverized to form aggregates and agglomerates of the Li-SiOx-C active material.

[0102] In manufacturing the Li-SiOx-C active material, elemental silicon (Si) can first react with a silicate material (SiOx) and be blended. The combination of silicon and silica is subjected to a reaction and grinding process to produce a powder. Carbon is added to the powder during a carbon coating process, and lithium is added to the powder during a lithium doping process. After the processes of adding carbon and lithium, the formed Li-SiOx-C material will be in a grading process to form a final available anode active material with a carbon coating, called Li-SiO. The relative density of the formed material can be about 2.1 g / cm at 25 °C. 3 .

[0103] In one embodiment, the energy storage device can have an initial charge specific capacity of 1500 mAh / g to 1600 mAh / g, preferably 1400 mAh / g to 1500 mAh / g, where the initial Coulombic efficiency is 90% to 94%; preferably 1350 mAh / g to 1400 mAh / g, where the initial Coulombic efficiency is 87% to 89%.

[0104] Lithium can be added in elemental form or in compound form. Some of these lithium compounds are listed herein. The D50 particle size of the Li-SiOx-C particles prepared in this way is 6 microns to 9 microns. Based on the total weight of the Li-SiOx-C active material, the BET surface area of the formed Li-SiOx-C material can be 3 m 2 / g to 4 m 2 / g, where the carbon content is 3 wt% to 4 wt%. A battery (also called an energy storage device) with a Li-SiOx-C anode can have an initial charge specific capacity of 1500 mAh / g to 1600 mAh / g with respect to Li / Li + + at 5 mV, and a battery with a Li-SiOx-C anode material can have an initial discharge specific capacity of 1400 mAh / g to 1500 mAh / g with respect to Li / Li+ at 2.0 V, where the initial Coulombic efficiency is 90% to 94%; and a battery with a Li-SiOx-C material can have an initial discharge specific capacity of 1350 mAh / g to 1400 mAh / g with respect to Li / Li+ at 1.0 V, where the initial Coulombic efficiency is 87% to 89%.

[0105] The manufacture of Li-SiOx and Li-SiOx-C active materials and corresponding electrodes is described in detail in U.S. Patent No. 9,825,290 B2 and U.S. Patent Application No. 2019 / 0237761 A1, the entire contents of which are incorporated by reference.

[0106] Based on the total weight of the anode active layer (which is solvent-free), the anode active material can be present in the anode active layer in an amount of 40 wt% to 90 wt%.

[0107] Preparation of anode

[0108] Anodes can be produced by first preparing a mixture (sometimes called a slurry) of a conductive element, an active material, and a binder in a solvent or solvent mixture. The method for manufacturing anodes can also be used for manufacturing cathodes. For the sake of brevity, this method will not be repeated during the manufacture of cathodes. The advantage of the binders described herein is that water, an alcohol, or a combination thereof can be used as the solvent to form a useful slurry. The slurry can then be directly coated onto a current collector or applied to a current collector having an intermediate adhesion layer.

[0109] The slurry can be prepared in a single step. Alternatively, the slurry can be prepared according to a multi-step method as shown in the Figure 2A flowchart, which depicts an example of method 600 provided for electrode 100 with respect to Figure 1 . Figure 2B Another way of manufacturing an anode for an energy storage device is depicted. At 610, a conductive material (e.g., a high aspect ratio carbon element) 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, an alcohol, or a combination thereof) to form an initial slurry.

[0110] At 620, the initial slurry is processed to ensure good dispersion of the solid materials in the slurry. This processing can include introducing mechanical energy into the mixture of the solvent and the solid materials (e.g., using an ultrasonic device, which is sometimes also referred to as an "ultrasonic") or other suitable mixing devices (e.g., a high shear mixer). For example, the mechanical energy introduced into the mixture can 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 greater. For example, the mechanical energy introduced into the mixture per kilogram of the mixture can be in the range of 0.4 kWh / kg to 1.0 kWh / kg or any sub-range thereof, such as 0.4 kWh / kg to 0.6 kWh / kg.

[0111] 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 an ultrasonic bath for nanoparticle applications. The high shear forces generated by ultrasonic cavitation have the ability to break up particle agglomerates and produce smaller and more uniform particle sizes. In addition to this, sonication can achieve a stable and uniform suspension of solids in a slurry. Typically, this causes dispersion and depolymerization of the solids and other breakdown. Examples of probe sonication devices include the Q-Series probe sonicators that can be commercially obtained from QSonica LLC of Newtown, Connecticut. Another example includes the Branson Digital SFX-450 sonicator that can be commercially obtained from Thomas Scientific of Swedesboro, New Jersey.

[0112] The local properties of each probe within the probe assembly can occasionally result in non-uniform mixing and suspension. This can be the case for example in large sample situations. This can be addressed by using a setup with a continuous flow cell and proper mixing. For example, with such a setup, mixing of the slurry will achieve a reasonably uniform dispersion.

[0113] Once processed, the initial slurry can have a viscosity in the range of 5,000 cps to 25,000 cps or any sub-range thereof (e.g., 6,000 cps to 19,000 cps).

[0114] At optional step 630 (e.g., used if no binder was added in step 610), a binder or additional binder can be applied as the surface treatment can form, in whole or in part, on the conductive material (e.g., high aspect ratio carbon elements) in the initial slurry. In some embodiments, at this stage, the surface treatment can self-assemble.

[0115] The resulting surface treatment can contain functional groups or other features as described in further steps below that can promote adhesion between the high aspect ratio carbon elements and the active material particles. For example, the functional groups on the binder can provide the surface treatment as described.

[0116] At 640, the active material particles can be combined with the initial slurry to form a final slurry that contains the active material particles together with the high aspect ratio carbon elements having the surface treatment formed thereon.

[0117] The active material can be added directly to the initial slurry. Alternatively, the active material can first be dispersed in a solvent (e.g., water, alcohol, or a combination thereof, using the techniques described above regarding the initial solvent) to form an active material slurry. Then, the active material slurry can be combined with the initial slurry to form a final slurry.

[0118] Suitable solvents are water, alcohol, or a combination thereof. Examples of alcohols are ethanol, methanol, propanol, butanol, ethylene glycol, propylene glycol, or a combination thereof. In addition to water and alcohol, other solvents can be added to facilitate the dissolution and / or dispersion of the polymer. Other solvents include polar solvents, non-polar 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 a combination 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 a combination thereof, can be used. Other non-polar solvents such as benzene, toluene, dichloromethane, carbon tetrachloride, hexane, diethyl ether, tetrahydrofuran, etc., or a combination thereof, can also be used. Cosolvents including at least one aprotic polar solvent and at least one non-polar solvent can also be used to change the dissolution ability of the solvent.

[0119] When water and alcohol are used as solvents for the anode active layer (for use in the anode), the ratio of water to alcohol is from 80:20 to 95:5, preferably from 88:12 to 92:8. In one exemplary embodiment, the ratio of water to alcohol is 90:10.

[0120] The solvent can be added to the mixture of the binder, conductive material, and active material in an amount of 10 wt% to 1000 wt%, preferably 50 wt% to 500 wt%, more preferably 100 wt% to 200 wt% based on the total weight of the solids used to form the active layer. Solids include materials that do not evaporate and ultimately enter the active material layer disposed on the current conductor (e.g., binder, conductive material, and active material).

[0121] 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 can be used. For example, this processing can use the techniques described above regarding 620. Alternatively, a planetary mixer, such as a multi-axis (e.g., three-axis or more) planetary mixer, can be used. The planetary mixer can be characterized by multiple blades, such as two or more mixing blades and one or more (e.g., two, three, or more) dispersion blades, such as disk dispersion blades.

[0122] During 650, due to the interaction between the surface treatment (e.g., binder) and the active material promoting the self-assembly process, the matrix entangled with the active material can self-assemble completely or partially.

[0123] In some embodiments, once processed, the final slurry will have a viscosity of 1,000 cps to 10,000 cps or any sub-range thereof (e.g., 2,500 cps to 6,000 cps).

[0124] At 660, the active layer 106 is formed from the final slurry. In some embodiments, the final slurry can be directly wet cast onto the current collector conductive layer 102 (or optional adhesion layer 104) and dried. As an example, casting can be carried out by applying at least one of heat and vacuum until substantially all of the solvent and any other liquid have been removed, thereby forming the active layer 106. It may be desirable to protect various parts of the underlying layer. For example, in the case where the electrode 100 is intended for single-sided operation, it may be desirable to protect the underside of the conductive layer 102. Protection can include, for example, protecting from the solvent by masking certain areas or providing a drainage device to direct the solvent away.

[0125] In another example, the final slurry can be at least partially dried elsewhere and then transferred onto the adhesion layer 104 or the conductive layer 102 using any suitable technique (e.g., roll-to-roll layer application) to form the active layer 106. As another example, the wet combined slurry can be placed on an intermediate material having a suitable surface and dried to form a layer (e.g., the active layer 106). Although any material having a suitable surface can be used as the intermediate material, exemplary intermediate materials include polytetrafluoroethylene (PTFE) because its properties facilitate subsequent removal from the surface. The layer can be formed in a press to provide a layer exhibiting the desired thickness, area, and density.

[0126] In yet another example, the final slurry can be formed into a sheet and appropriately coated onto the adhesion layer 104 or the conductive layer 102. For example, the final slurry can be applied through a slot die to control the thickness of the applied layer. As another example, the slurry can be applied and then leveled to the desired thickness, for example, using a doctor blade. A variety of other techniques can be used to apply the slurry. For example, coating techniques can include, but are not limited to: comma coating; reverse comma coating; doctor blade coating; slot die coating; direct gravure coating; air knife coating; chamber doctor blade coating; displacement gravure coating; single-pass roll kiss coating; reverse kiss coating with a small diameter gravure roll; rod coating; triple reverse roll coating (top feed); triple reverse roll coating (feed die); reverse roll coating, etc.

[0127] The viscosity of the final slurry can vary depending on the application technique. For example, for comma coating, the viscosity can be in the range of about 1,000 cps to about 200,000 cps. Lip die coating provides coating of a slurry having a viscosity of about 500 cps to about 300,000 cps. Reverse kiss coating provides coating of a slurry having a viscosity between about 5 cps and 1,000 cps. In some applications, the corresponding layer can be formed by multiple passes.

[0128] If desired, the active layer 106 formed from the final slurry can be compressed (e.g., using a calendering device) before or after being applied to the electrode 100. The slurry can be partially or fully dried (e.g., by applying heat, vacuum, or a combination thereof) before or during the compression process. For example, in some embodiments, the active layer can be compressed to a final thickness that is less than 90%, 80%, 70%, 50%, 40%, 30%, 20%, 10%, or less of its thickness before compression (e.g., in a direction perpendicular to the current collector layer 102).

[0129] When a partially dried layer is formed during the coating or compression process, the layer can subsequently be fully dried (e.g., by applying heat, vacuum, or a combination thereof). In some embodiments, substantially all of the solvent is removed from the active layer 106.

[0130] The solvent used to form the slurry can be recovered and recycled into the slurry preparation process.

[0131] The active layer 106 can be compressed, for example, to break some of the high aspect ratio carbon elements or other carbon-containing materials of the composition to increase the surface area of the corresponding layer. This compression treatment can increase one or more of the adhesion between layers, the ion transport rate within the layer, and the surface area of the layer. In various embodiments, compression can be applied before or after applying or forming the corresponding layer on the electrode 100.

[0132] In the case of using calendering to compress the active layer 106, the calendering equipment can be set such that the gap spacing is equal to less than 90%, 80%, 70%, 50%, 40%, 30%, 20%, 10% or less of the thickness of the layer before compression (e.g., set to about 33% of the thickness of the layer before compression). The calendering roll can be configured to provide a suitable pressure, such as greater than 1 ton / cm of roll length, greater than 1.5 tons / cm of roll length, greater than 2.0 tons / cm of roll length, greater than 2.5 tons / cm of roll length or more. The compressed active layer can have a density in the range of 1 g / cc to 10 g / cc or any sub-range thereof (such as 2.0 g / cc to 4.0 g / cc). Note that the cathode active layer has a density of 2 g / cc to 4 g / cc. The anode active layer typically has a density of 1.0 g / cc to 1.8 g / cc. The calendering process can be carried out at a temperature in the range of 20 °C to 140 °C or any sub-range thereof. In some embodiments, the active layer 106 can be preheated before calendering (e.g., at a temperature in the range of 20 °C to 100 °C or any sub-range thereof).

[0133] Process 600 can include any one of the following features (individually or in any suitable combination):

[0134] The initial slurry has a solids content in the range of 0.1 wt% to 20.0 wt% (or any sub-range thereof), and / or the final slurry has a solids content in the range of 10.0 wt% to 80 wt% (or any sub-range thereof).

[0135] As described, the conductive and binder scaffold or matrix can hold the active material particles together to form a cohesive layer that is also firmly attached to the metal current collector. Such an active material structure can be produced during slurry preparation and subsequently during roll-to-roll ("R2R") coating and drying processes. One of the main advantages of this technique is its scalability and "drop-in" nature, as various embodiments are compatible with conventional electrode manufacturing processes.

[0136] The techniques described herein can be used to form a matrix during slurry preparation: the high aspect ratio carbon materials are properly dispersed and chemically functionalized as needed using techniques such as those described above for process 600 of FIG. 2. The chemical functionalization is designed to form an organized self-assembled structure with the surface of the active material particles (e.g., NMC particles for the cathode, described in detail below, or silicon particles ("Si") or silicon oxide ("SiOx") particles in the case of the anode). The slurry thus formed can be based on water and / or alcohol solvents for the cathode and water for the anode, and such solvents are very easy to evaporate and handle during the manufacturing process. Electrostatic interactions promote the self-organized structure in the slurry, and after the drying process, the binding between the carbon matrix with the active material particles thus formed and the surface of the current collector is promoted through surface treatment (e.g., functional groups on the matrix) and strong entanglement of the active material in the carbon matrix.

[0137] By adjusting the entanglement effect through surface functionalization, the mechanical properties of the electrode can be varied according to the application and mass loading requirements.

[0138] After coating and drying, the electrode can undergo a calendaring step to control the density and porosity of the active material. In the NMC cathode electrode, a density of >= 3.5 g / cc or greater and a porosity of 20% or greater can be achieved. The porosity can be optimized according to the mass loading and cell requirements of the lithium-ion battery. For anodes based on silicon oxide or silicon, the porosity can be specifically controlled to accommodate the expansion of the active material during the lithiation process.

[0139] The teachings herein can provide a reduction of up to about 20% in $ / kWh. By using water, alcohol, or a mixed water / alcohol as the solvent, which is easy to evaporate, the electrode production rate can be higher, and more importantly, the energy consumption of the long dryer can be significantly reduced. The conventional recovery system required when using NMP or similar compounds as the solvent is also greatly simplified when using water, alcohol, or their combination.

[0140] The teachings herein provide an active layer with a 3D matrix that can increase the electrode conductivity significantly by 10 to 100 times compared to electrodes using conventional binders such as PVDF, which enables fast charging at the cell level. Using this technique, thick electrode coatings in the cathode can reach 150 um (or more) on each side of the current collector. The solvent used in combination with the strong 3D carbon matrix for the slurry is designed to achieve thick wet coatings without cracking during the drying step. The thick cathode with a high-capacity anode can enable a significant jump in energy density, reaching 400 Wh / kg or higher.

[0141] Cathode

[0142] As described above, the cathode includes a cathode conductive element, a cathode binder, and a cathode active material that are mixed together to form a mixture. The mixture is disposed on a current collector and dried to form an active layer. The various components of the cathode active material layer are described in detail below.

[0143] Cathode conductive element

[0144] The cathode conductive element may include carbon nanotubes that are arranged to form a percolation network including voids. The cathode active material is located in the voids of the percolation network. The cathode conductive material is similar to those described above for the anode conductive material.

[0145] Cathode adhesive

[0146] 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, 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 (usually a metal) and dried to form a solid cathode active layer.

[0147] The cathode polymer binder (for use in the cathode) includes a first cathode polymer binder that includes a copolymer of polyamide, polyacrylic acid, or acrylate copolymer. The cathode polymer binder (for use in the cathode) also includes a second cathode polymer binder that includes polyvinylpyrrolidone (PVP).

[0148] The polyamide (for use in the first cathode polymer binder) may include aliphatic polyamide, aromatic polyamide, or a combination thereof. In one embodiment, the polyamide includes a class of resins called nylons, which are characterized by the presence of an amide group (-C(O)NH-). Any amide-containing polymer can be used alone or in combination: Nylon-6 and Nylon-6,6 are suitable polyamide resins that are available from various commercial sources. However, other polyamides 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 (PA610), Nylon 11 (PA11), Nylon 12 (PA 12), Nylon 6-3-T (PA 6-3-T), polyphthalamide (PA MXD 6), polyphthalamide (PPA), and / or polyether block amide, and others such as amorphous nylon are also useful. Mixtures of various polyamides and various polyamide copolymers are also useful.

[0149] Polyamides can be obtained by many well-known methods, such as those described in U.S. Patents 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 the polymerization product of caprolactam. Nylon-6,6 is the condensation product of adipic acid and 1,6-diaminohexane. Similarly, nylon 4,6 is the condensation product between adipic acid and 1,4-diaminobutane. In addition to adipic acid, other useful diacids for preparing nylon include azelaic acid, sebacic acid, dodecanedioic acid, and terephthalic acid and isophthalic acid, etc. Other useful diamines include m-xylylenediamine, bis-(4-aminophenyl)methane, bis-(4-aminocyclohexyl)methane; 2,2-bis-(4-aminophenyl)propane, 2,2-bis-(4-aminocyclohexyl)propane, etc. Copolymers of caprolactam with diacids and diamines are also useful.

[0150] Polyamides are generally derived from the polymerization of organic lactams having 4 to 12 carbon atoms. In one embodiment, the lactam is represented by formula (I)

[0151]

[0152] wherein n is 3 to 11. In one embodiment, the lactam is ε-caprolactam where n is equal to 5.

[0153] 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)

[0154]

[0155] wherein n is 3 to 11. In one embodiment, the amino acid is ε-aminohexanoic acid where n is equal to 5. Polyamides can also be formed by polymerizing aliphatic dicarboxylic acids having 4 to 12 carbon atoms and aliphatic diamines having 2 to 12 carbon atoms. In one embodiment, the aliphatic diamine is represented by formula (III)

[0156] H2N-(CH2) n —NH2(III)

[0157] 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 the dicarboxylic acid to the diamine is from 0.66 to 1.5. Within this range, a molar ratio greater than or equal to 0.81 is generally beneficial. In another embodiment, the molar ratio is greater than or equal to 0.96. In another embodiment, the molar ratio is less than or equal to 1.22. In another embodiment, the molar ratio is less than or equal to 1.04. 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.

[0158] Poly(meth)acrylic acid / poly(meth)acrylate and their copolymers are listed and described above and will not be repeated here for the sake of brevity.

[0159] Based on the weight of the cathode mixture (which comprises a cathode polymer binder (a first cathode polymer binder and a second cathode polymer binder), a cathode active material, a cathode conductive material, and a solvent), the first cathode polymer binder is present in an amount of from 0.1 wt% to 0.4 wt%, preferably from 0.15 wt% to 0.375 wt%. Based on the total weight of the cathode active layer, the first cathode polymer binder is present in the cathode active layer in an amount of from 0.2 wt% to 0.5 wt%, preferably from 0.25 wt% to 0.45 wt%.

[0160] The cathode active layer comprises a second cathode polymer binder, which comprises polyvinylpyrrolidone (PVP). In addition to acting as the second cathode polymer binder, PVP can also be used as a dispersant for the cathode active material and the cathode conductive filler.

[0161] Based on the weight of the cathode mixture (which comprises a cathode polymer binder (a first cathode polymer binder and a second cathode polymer binder), a cathode active material, a cathode conductive material, and a solvent), the second cathode polymer binder is present in an amount of from 0.1 wt% to 0.4 wt%, preferably from 0.15 wt% to 0.375 wt%. Based on the total weight of the cathode active layer, the second cathode polymer binder is present in the cathode active layer in an amount of from 0.2 wt% to 0.5 wt%, preferably from 0.25 wt% to 0.45 wt%.

[0162] Cathode active material

[0163] The cathode active material may include lithium cobalt oxide (LCO, sometimes referred to as "lithium cobaltate" or "lithium cobaltite"). Examples of LCO formulations include LiCoO2; lithium nickel manganese cobalt oxide (NMC, having a variant formula LiNiMnCo); lithium manganese oxide (LMO having a variant formula such as LiMn2O4, Li2MnO3, etc. or a combination thereof); lithium titanate oxide (LTO, one variant formula of which is Li4Ti5O 12 ); lithium iron phosphate oxide (LFP, one variant formula of which is LiFePO4), lithium nickel cobalt aluminum oxide (and its variants as NCA), and other similar materials. Other variants of the foregoing may be included.

[0164] In one embodiment, the cathode active material may include NMC, NCA, NCMA, or a combination thereof.

[0165] When NMC is used as the cathode active material, nickel-rich NMC can be used. For example, a variant of NMC can be LiNi x Mn y Co (1-x-y) , where x is equal to or greater than about 0.7, 0.75, 0.80, 0.85 or greater, y is equal to or greater than 0.1, 0.15, 0.2 or 0.25, 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 may include lithium nickel manganese cobalt oxide (LiNi x Mn y Co z O2). Variants of this formula that can be used in the active material layer include NMC 111 (detailed 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.

[0166] In one embodiment, NMC91 can be used as the cathode active material. NMC91 contains 91 mol% or more nickel. An example of NMC91 is LiNi 0.91 Co 0.06 Mn 0.03 O2. Li[Ni 1-x-–y Co x Al y O2 (NCA) can also be used as the cathode active material. An example of NCA is NCA89.

[0167] In another embodiment, the cathode active material can be an NCMA material. An example of NCMA is Li[Ni 0.89 Co 0.05 Mn 0.05 Al 0.01 O2, also known as NCMA89.

[0168] In one embodiment, the cathode active material may further comprise a nickel-rich combination of nickel, manganese, and cobalt. Lithium-nickel-manganese-cobalt-oxide (LiNiMnCoO2), abbreviated as NMC, provides strong overall performance, excellent specific energy, and the lowest self-heating rate among all mainstream cathode powders. Based on the total weight of the NMC blend, the NMC powder can contain nickel in an amount of 20 wt% to 40 wt%, manganese in an amount of 20 wt% to 40 wt%, and cobalt in an amount of 20 wt% to 40 wt%. Although the term "NMC powder" can refer to a variety of blends, it is desirable to use a blend comprising 33 wt% nickel, 33 wt% manganese, and 33 wt% cobalt. This blend (sometimes referred to as 1-1-1 (NMC 111)) is useful for applications that use frequent cycling (automotive, energy storage) because of the reduced material cost achieved by the lower cobalt content (nickel-rich combination of nickel, manganese, and cobalt (NMC)). Based on the total weight of the NMC blend, the NMC powder can contain nickel in an amount of 20 wt% to 40 wt%, manganese in an amount of 20 wt% to 40 wt%, and cobalt in an amount of 20 wt% to 40 wt%. Although the term "NMC powder" can refer to a variety of blends, it is desirable to use a blend comprising 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) because of the reduced material cost achieved by the lower cobalt content. Lithium-nickel-manganese-cobalt-oxide (LiNiMnCoO2) provides strong overall performance, excellent specific energy, and the lowest self-heating rate among all mainstream cathode powders. Lithium-rich NCM materials, such as 424 and 523 manufactured by BASF, can also be used as the cathode active material.

[0169] Generally speaking, adding an increased active material loading (measured as a function of the total cathode weight) to the cathode results in increased areal capacity and specific energy levels in the cathode.

[0170] As described above, the cathode active material can be included or accommodated within a network of high aspect ratio conductive materials present in the cathode active layer. Based on the total weight of the cathode mixture (the mixture for making the cathode active layer containing a cathode binder material, a cathode active material, a cathode conductive material, and a solvent), the cathode active material can be present in the mixture for forming the cathode in an amount of 55 wt% to 75 wt%, preferably 60 wt% to 70 wt%. Based on the total weight of the cathode active layer, the cathode active material is present in the cathode active layer (which is solvent-free) in an amount of 95 wt% to 98.5 wt%.

[0171] Manufacture of cathode active layer

[0172] The cathode active layer is disposed on a current collector. The cathode active layer is fabricated in a manner similar 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 the cathode current collector. The solvent is evaporated, and the cathode current collector can undergo further finishing operations in a roll mill to produce the cathode, which can then be used in an energy storage device as detailed below.

[0173] Energy storage device

[0174] Once the electrode 100 has been assembled, the electrode 100 can be used to assemble an energy storage device. The assembly of the energy storage device can follow conventional steps for assembling the electrode with a separator and placing it within a housing (e.g., a can or a pouch), and can also include additional steps for adding an electrolyte and sealing the housing.

[0175] One exemplary embodiment includes a lithium-ion battery energy storage device in the form of a pouch cell, which combines a Ni-rich NMC active material in the cathode with a SiOx and graphite blend active material in the anode, where both the anode and the cathode are fabricated using the 3D carbon matrix process as described herein.

[0176] Figure 3 A schematic diagram of an electrode arrangement of an example of a pouch cell device is shown. As shown, the cathode active layer 760 (e.g., an active layer according to various embodiments disclosed herein) is on the opposite side of a current collector 710 (e.g., an aluminum foil current collector) to form a bilateral cathode disposed between two unilateral anodes. Each unilateral anode has an anode layer 740 or 750 (e.g., an active layer including a network of carbon elements such as those 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 with an electrolyte (not shown). This arrangement can be accommodated in a pouch cell of a type known in the art.

[0177] In Figure 4In it, a cross-section of an energy storage device (ESD) 810 is shown. The energy storage device (ESD) 810 includes a housing 811. The housing 811 has two terminals 800 provided on its exterior. The terminals 800 provide an internal electrical connection to a storage cell 812 housed within the housing 811 and an external electrical connection to an external device such as a load or a charging device (not shown). The energy storage device disclosed herein may be a battery, a capacitor, a supercapacitor, etc.

[0178] Example

[0179] This example was conducted to determine the effect of the Li-SiOx-C anode loading on the cathode performance and thus on the battery performance. The cathode loading was conducted at 4.0 mAh / cm 2 to 7.0 mAh / cm 2 (areal capacity). Figure 5 is a graph depicting specific energy versus the weight percentage of Li-SiOx-C loading. The effect of the Li-SiOx-C loading and its specific energy was conducted from 0 wt% to 95 wt% loading. From Figure 5 it can be seen that the specific energy increases as the Li-SiOx-C loading increases 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 depicting specific energy versus the cathode mass loading (areal capacity) for different weight percentages of Li-SiOx-C loading. Figure 6 shows that an increase in the Li-SiOx-C content in the cathode results in an increase in the specific energy (measured in watt-hours per kilogram (Wh / Kg)).

[0180] Table 1 below shows the battery (energy storage device) performance of a battery containing a cathode and an anode, the cathode containing NCM-91 and the anode containing a graphite-SiOx blend (which contains 35 wt% graphite and 65 wt% SiOx). The cathode has a density between 3.4 and 3.6 g / cm 3 and the anode has a density between 1.45 and 1.60 g / cm 3 .

[0181] Table 1

[0182]

[0183] As can be seen from Table 1, the battery (also referred to as an energy storage device) exhibits a specific energy between 300 watt-hours per kilogram and 450 watt-hours per kilogram (Wh / kg), preferably between 340 Wh / kg and 400 Wh / kg and more preferably between 360 Wh / kg and 395 Wh / kg. The battery has an energy density between 900 watt-hours per liter and 1000 watt-hours per liter (Wh / L), preferably between 930 Wh / L and 995 Wh / L and more preferably between 940 Wh / L and 990 Wh / L. The initial Coulombic efficiency (ICE) of the battery is in the range of 0.87 to 0.91, preferably 0.89 to 0.90.

[0184] All ranges disclosed herein include the endpoints, and the endpoints can be combined with each other independently (e.g., a range of "up to 25 wt%, or more specifically, 5 wt% to 20 wt%" includes the endpoints and all intermediate values of the range of "5 wt% to 25 wt%", etc.). Additionally, the upper and lower limits can be combined to form a range (e.g., "at least 1 wt% or at least 2 wt%" and "up to 10 wt% or 5 wt%" can be combined into a range of "1 wt% to 10 wt%", or "1 wt% to 5 wt%", or "2 wt% to 10 wt%", or "2 wt% to 5 wt%").

[0185] The present disclosure may alternatively comprise any suitable components disclosed herein, consist of, or consist essentially of the same. The present disclosure may additionally or alternatively be formulated to be free or substantially free of any components, materials, ingredients, adjuvants, or substances used in prior art compositions or not necessary for achieving the functions or objectives of the present disclosure.

[0186] All cited patents, patent applications, and other references are incorporated herein by reference in their entirety. However, if a term in this patent application conflicts or contradicts a term in the incorporated reference, the term from this patent application prevails over the conflicting term from the incorporated reference.

[0187] Unless otherwise indicated herein, all test standards are the latest standards effective 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 standard appears.

Claims

1. An anode, the anode comprising: A current collector; An anode active layer disposed on the current collector, wherein the anode active layer comprises anode active particles, an anode conductive material, and an anode binder; wherein the anode binder comprises a copolymer, the copolymer comprising a first repeating unit and a second repeating unit; wherein the first repeating unit is derived from the polymerization of a first monomer comprising an ether bond or a plurality of hydroxyl groups, and wherein the second repeating unit is derived from the polymerization of an ethylenically unsaturated monomer comprising a hydrophilic side group.

2. The anode according to claim 1, wherein the hydrophilic side group is a carboxylic acid group or a carboxylate group.

3. The anode according to claim 1, wherein the anode conductive element forms a percolation network.

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

5. The anode according to any one of the preceding claims, wherein the anode conductive element comprises a network of high aspect ratio carbon elements.

6. The anode according to any one of the preceding claims, wherein the high aspect ratio carbon element comprises a carbon nanotube.

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

8. The anode according to any one of the preceding claims, wherein the anode active material comprises lithium silicate having the structure Li x Si y O z , where x is from 1 to 15, y is from 0 to 4, and z is from 0 to 9.

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

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

11. The anode according to claim 8, the anode having an initial Coulombic efficiency of 87% to 89%.

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

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

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

15. The anode according to claim 5, wherein the network of high aspect ratio carbon elements comprises: A first group of carbon nanotubes, wherein the first group of carbon nanotubes comprises a plurality of first carbon nanotubes or a plurality of bundles of first carbon nanotubes; and A second group of carbon nanotubes, wherein: The second group of carbon nanotubes comprises a plurality of second carbon nanotubes or a plurality of bundles of second carbon nanotubes; and The second group of carbon nanotubes has one or more properties different from those of the first group of carbon nanotubes.

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

17. The electrode according to claim 15, wherein the second group of carbon nanotubes comprises multi-walled carbon nanotubes.

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

1.

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

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

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

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

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

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

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

26. The energy storage device according to claim 22, wherein the energy storage device exhibits an initial charge specific capacity of 1400 mAh / g to 1500 mAh / g, wherein the initial Coulombic efficiency is 90% to 94%.

27. The energy storage device according to claim 22, wherein the energy storage device exhibits an initial charge specific capacity of 1350 mAh / g to 1400 mAh / g, wherein the initial Coulombic efficiency is 87% to 89%.

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

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

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