electrodes for energy storage devices

Abstract

Disclosed is an electrode active layer comprising a network of high-aspect-ratio carbon elements (e.g., carbon nanotubes, carbon nanotube bundles, graphene flakes, etc.) that entangle or intertwine with the active material, thereby providing a highly conductive scaffold that supports the layer. A surface treatment can be applied to the high-aspect-ratio carbon elements to promote adhesion to the active material and any underlying electrode layers, improving the overall cohesion and mechanical stability of the active layer. The surface treatment forms only a thin (in some cases, even monomolecular) layer on the network and is free of bulk binder material, thereby leaving large voids that can instead be filled with active material. The resulting active layer can be formed with excellent mechanical stability, even at high thicknesses and high active material mass loadings.

Description

[Technical Field]

[0001] Related applications This application claims the interests and priority thereto of U.S. Provisional Patent Application No. 63 / 041801, filed June 19, 2020; U.S. Provisional Patent Application No. 62 / 954771, filed December 30, 2019; U.S. Provisional Patent Application No. 62 / 871041, filed July 5, 2019; and U.S. Provisional Patent Application No. 63 / 003341, filed April 1, 2020. The entire contents of each of the aforementioned references are incorporated herein by reference. [Background technology]

[0002] Lithium batteries are used in a wide range of products, including medical devices, electric vehicles, aircraft, and consumer products such as laptop computers, mobile phones, and cameras. With their high energy density, high operating voltage, and low self-discharge, lithium-ion batteries have outperformed the secondary battery market and continue to find new applications in products and developing industries.

[0003] Generally, a lithium-ion battery ("LIB" or "LiB") comprises a negative electrode, a positive electrode, and an electrolyte material such as an organic solvent containing a lithium salt. More specifically, the negative electrode and positive electrode (collectively referred to as "electrodes") are formed by mixing either the negative electrode active material or the positive electrode active material with a binder and a solvent to form a paste or slurry, and then coating and drying this paste or slurry onto a current collector such as aluminum or copper to form a film on the current collector. The negative electrode and positive electrode are then stacked or coiled before being housed in a pressurized casing containing the electrolyte material, and all of these together form a lithium-ion battery.

[0004] In conventional electrodes, the binder is used with sufficient adhesive and chemical properties to maintain contact with the current collector, even when the film coated on the current collector is manipulated to fit into a pressurized battery casing. Because the film contains the electrode active material, if the film does not maintain sufficient contact with the current collector, significant interference with the electrochemical properties of the battery can occur. Furthermore, it has been 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.

[0005] Therefore, binders such as cellulose binders or crosslinked polymer binders have been used to provide good mechanical properties. However, such binder materials have undesirable effects. For example, most binders fill the volume within the electrode active layer, which can otherwise be used to increase the mass load of the active material and reduce the conductivity of the electrode. Furthermore, binders tend to react electrochemically with the electrolyte used in batteries (especially in high-voltage, high-current, and / or high-temperature applications), leading to a degradation of battery performance. [Overview of the project]

[0006] The applicants have found that electrodes can be configured to exhibit excellent mechanical stability without requiring bulk polymer binders. In one embodiment, the disclosure describes an embodiment of an electrode active layer comprising a network of high aspect ratio carbon elements (e.g., carbon nanotubes, carbon nanotube bundles, graphene flakes, etc.) that provides a highly conductive scaffold that entangles or intertwines with the active material, thereby supporting the layer. As detailed below, a surface treatment agent can be applied to the high aspect ratio carbon elements to promote adhesion to the active material and any underlying electrode layer (e.g., a current collector layer), thereby improving the overall cohesiveness and mechanical stability of the active layer. This surface treatment agent forms only a thin (in some cases, even monomolecular) layer on the network and does not contain bulk binder material, thus leaving large voids that can instead be filled with the active material. The resulting active layer can be formed with excellent mechanical stability, even with large thicknesses and high active material mass loads.

[0007] In another aspect, the present disclosure describes a method comprising: dispersing high aspect ratio carbon elements and a surface treatment agent material in a solvent to form an initial slurry, wherein the dispersion step results in the formation of a surface treatment agent on the high aspect ratio carbon; mixing an active material into the first slurry to form a final slurry; coating the final slurry onto a substrate; and drying the final slurry to form an electrode active layer.

[0008] Various embodiments may include any of the features or elements described herein, individually or in any preferred combination. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram of an electrode characterized by an active material layer. [Figure 2] This is a detailed example of one embodiment of the active material layer. [Figure 3] This is a detailed example of an active material layer in another embodiment. [Figure 4]It is an electron micrograph of an active material of the type described in this specification. [Figure 5] It is a schematic diagram of an energy storage cell. [Figure 6] It is a flowchart illustrating a method of fabricating the electrode of FIG. 1. [Figure 7] It shows a schematic diagram of a pouch cell battery. [Figure 8] It shows a summary of the functional parameters of a pouch cell battery for EV applications. [Figure 9] It shows a summary of the functional parameters of a pouch cell battery. [Figure 10] It shows the results of a performance comparison evaluation between a pouch cell battery featuring a binder-free cathode (left plot) and a pouch cell battery featuring a binder-based cathode (right plot). [Figure 11] It shows the results of a performance comparison evaluation between a pouch cell battery featuring a binder-free cathode (upper trace) and a pouch cell battery featuring a binder-based cathode (lower trace). [Figure 12] It is a schematic diagram of a half-cell lithium battery device. [Figure 13] It is a plot showing the potential (relative to the Li / Li+ potential) versus specific capacity of a binder-free cathode half-cell (solid line trace) and a reference binder-based cathode half-cell (dashed line trace) at various current densities. [Figure 14] It is a plot showing the potential (relative to the Li / Li+ potential) versus volume capacity of a binder-free cathode, having cells (solid line trace) and a reference binder-based cathode half-cell (dashed line trace) at various current densities. [Figure 15] It shows a plot of volume capacity versus current density for a binder-free cathode half-cell (upper trace) and a reference binder-based cathode half-cell (lower trace). [Figure 16]The Nyquist plots resulting from electrochemical impedance spectroscopy of several binder-free cathode half-cells (marked with square, circular, and triangular traces) and a reference binder-based cathode half-cell are shown. The binder-free cathode half-cells exhibit significantly better performance than the reference cell. [Modes for carrying out the invention]

[0010] Referring to Figure 1, an electrode 10 is shown, which includes an active layer 100 disposed on a current collector 101. Some embodiments may include an optional adhesive layer 102 disposed between the active layer 101 and the current collector 102. In other embodiments, the adhesive layer 102 may be omitted.

[0011] The current collector 101 may be a conductive layer such as a metal foil. An optional adhesive layer 102 (which may be omitted in some embodiments) may be a layer of material that promotes adhesion between the current collector 102 and the active layer 100. Examples of suitable materials for the current collector 101 and the optional adhesive layer 102 are described in International Patent Publication No. 2018 / 102652, published on June 7, 2018.

[0012] electrode active layer In some embodiments, the active layer 100 may include a three-dimensional network 200 of high aspect ratio carbon elements 201 that define voids within the network 200. Multiple active material particles 300 are arranged within the voids in the network 200. Thus, the active material particles entangle with or become entangled in the network 200, thereby improving the cohesiveness of the active layer 100.

[0013] In some embodiments, a surface treatment agent 202 (not shown, see Figure 2) is applied to the surface of the high aspect ratio carbon elements 201 of the network 200. The surface treatment agent promotes adhesion between the high aspect ratio carbon elements and the active material particles 300. The surface treatment agent may also promote adhesion between the high aspect ratio carbon elements and the current collector 100 (also referred to herein as the “conductive layer”) and / or an optional adhesive layer 102.

[0014] As used herein, the term “high aspect ratio carbon element” refers to a carbonaceous element having a size in one or more dimensions (“major dimensions”) that is significantly larger than the size of the element in a cross-sectional dimension (“minor dimensions”).

[0015] For example, in some embodiments, the high aspect ratio carbon element 201 may include a flake or plate-like element having two main dimensions and one minor dimension. For example, in some such embodiments, the ratio of the lengths of each main dimension may be at least 5, 10, 100, 500, 1,000, 5,000, or 10,000 times that of the minor dimension. Exemplary elements of this type include graphene sheets or flakes.

[0016] For example, in some embodiments, the high aspect ratio carbon element 201 may include an elongated rod or fibrous element having one main dimension and two sub-dimensions. For example, in some such embodiments, the ratio of the length of the main dimension may be at least 5, 10, 100, 500, 1,000, 5,000, or 10,000 times or more each of the sub-dimensions. Exemplary elements of this type include carbon nanotubes, bundles of carbon nanotubes, carbon nanorods, and carbon fibers.

[0017] In some embodiments, the high aspect ratio carbon element 201 may include single-walled nanotubes (SWNTs), double-walled nanotubes (DWNTs), or multi-walled nanotubes (MWNTs), carbon nanorods, carbon fibers, or mixtures thereof. In some embodiments, the high aspect ratio carbon element 201 may be formed from interconnection bundles, clusters, or aggregates of CNTs or other high aspect ratio carbon materials. In some embodiments, the high aspect ratio carbon element 201 may include graphene formed in the form of sheets, flakes, or curved flakes, and / or high aspect ratio cones, rods, etc.

[0018] In some embodiments, the electrode active layer 100 may contain little to no bulk binder material, leaving more space within the network 200 to be occupied by the active material particles 300. For example, in some embodiments, the active layer 200 contains less than 10% by weight, less than 1% by weight, less than 0.1% by weight, less than 0.01% by weight, or less than that of a binder material (e.g., a polymer or cellulosic binder material) disposed in the voids.

[0019] For example, in some embodiments, the electrode active layer contains or substantially no polymer material or any material other than the active material 300, and is a network 200 composed of high aspect ratio carbon elements 201 and a surface treatment agent 202 disposed thereon.

[0020] In some embodiments, the network 200 is composed of carbon for the majority or entirely. For example, in some embodiments, the network 200 is composed of at least 90% by weight of carbon, at least 95% by weight of carbon, at least 96% by weight of carbon, at least 97% by weight of carbon, at least 98% by weight of carbon, at least 99% by weight of carbon, at least 99.5% by weight of carbon, at least 99.9% by weight of carbon, or more.

[0021] In some embodiments, the size (e.g., average size, median size, or minimum size) of the high aspect ratio carbon elements 201 forming the network 200 along one or two main dimensions may be at least 0.1 μm, 0.5 μm, 1 μm, 5 μm, 10 μm, 50 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 7000 μm, 800 μm, 900 μm, 1000 μm, or greater. For example, in some embodiments, the size (e.g., average size, median size, or minimum size) of the elements 201 forming the network 200 may be in the range of 1 μm to 1000 μm, or any sub-range thereof, for example, 1 μm to 600 μm.

[0022] In some embodiments, the size of the elements may be relatively uniform. For example, in some embodiments, more than 50%, 60%, 70%, 80%, 90%, 95%, and 99% or more of the elements 201 may have a size that aligns with one or two main dimensions within 10% of the average size of the elements 201 constituting the network 200.

[0023] The applicants have found that the type of active layer 100 described herein can provide exemplary performance (e.g., high conductivity, low resistance, high voltage performance, and high energy and power density) even when the mass fraction of the elements 201 constituting the network 200 within the layer 100 is considerably low, thereby enabling a high mass load of active material particles 300. For example, in some embodiments, the active layer 100 may consist of active material particles 300 in amounts of at least about 50% by weight (weight percent), 60% by weight, 70% by weight, 75% by weight, 80% by weight, 85% by weight, 90% by weight, 95% by weight, 96% by weight, 97% by weight, 98% by weight, 99% by weight, 99.5% by weight, or more.

[0024] In some embodiments, the network 200 forms an interconnection network of highly conductive paths for current flow (e.g., electron or ion transport) through the active layer 100. For example, in some embodiments, highly conductive junctions may occur where elements 201 of the network intersect each other, or where elements 201 of the network are close enough to allow quantum tunneling of charge carriers (e.g., electrons or ions) from one element to the next. While elements 201 may constitute a relatively low mass fraction of the active layer (e.g., less than 10 wt%, 5 wt%, 4 wt%, 3 wt%, 2 wt%, 1 wt% or less, e.g., in the range of 0.5 wt% to 10 wt%, or any sub-range thereof, e.g., 1 wt% to 5.0 wt%), the interconnection network of highly conductive paths formed within the network 200 may provide long conductive paths (e.g., conductive paths about the thickness of the active layer 100) for facilitating current flow in and through the active layer 100.

[0025] For example, in some embodiments, the network 200 may include one or more structures of interconnected elements 201, the structures having a total length along one or more dimensions that is longer than 2, 3, 4, 5, 10, 20, 50, 100, 500, 1,000, or 10,000 times the average length of the constituent elements 201 that make up the structure. For example, in some embodiments, the network 200 may include one or more structures of interconnected elements 200, the structures having a total length in the range of 2 to 10,000 times (or any sub-range) of the average length of the constituent elements 201 that make up the structure. For example, in some embodiments, the network 200 may include highly conductive paths having lengths greater than 100 μm, 500 μm, 1,000 μm, or 10,000 μm, for example, in the range of 100 μm to 10,000 μm in any sub-range.

[0026] As used herein, the term “highly conductive path” should be understood as a path formed by interconnected elements 201 having a conductivity higher than that of the active material particles intertwined within the network 200.

[0027] While we do not wish to be bound by theory, in some embodiments, network 200 can be characterized as an electrically interconnected network of elements 201 that exhibit connectivity above a penetration threshold. The penetration threshold is a mathematical concept related to penetration theory, which is the formation of long-range connections in random systems. Below the threshold, there are no so-called "huge" connected components as large as the system size, and above the threshold, there are huge components as large as the system size.

[0028] In some embodiments, the penetration threshold can be determined by increasing the mass fraction of elements 201 within the active layer 100 while measuring the conductivity of the layer, keeping all other properties of the layer constant. In some such cases, the threshold can be identified by a mass fraction beyond which the conductivity of the layer increases rapidly, and / or a mass fraction beyond which the conductivity of the layer increases only slowly with the addition of more elements 201. Such behavior indicates exceeding the threshold required to form an interconnect structure that provides a conductive path having a length approximately the size of the active layer 100.

[0029] Figure 2 shows a detail view of high-aspect-ratio carbon elements 201 of the network 200 (as shown in Figure 1), located near several active material particles 300. In the shown embodiment, the surface treatment agent 202 on the elements 201 is a surfactant layer bonded to the outer layer of the surface of the elements 201. As shown, the surfactant layer comprises a plurality of surfactant elements 210, each having a hydrophobic end 211 and a hydrophilic end 212, with the hydrophobic ends positioned proximal to the surface of the carbon elements 201 and the hydrophilic ends 212 positioned distal to the surface.

[0030] In some embodiments where the carbon element 201 is hydrophobic (typically as in the case of nanoform carbon elements such as CNTs, CNT bundles, and graphene flakes), the hydrophobic end 211 of the surfactant element 210 will be attracted to the carbon element 201. Thus, in some embodiments, the surface treatment agent 202 may be a self-assembling layer. For example, as detailed below, in some embodiments, when the element 201 is mixed with the surfactant element 210 in a solvent to form a slurry, the surface treatment agent 202 layer self-assembles on the surface due to electrostatic interactions between the elements 201 and 210 in the slurry.

[0031] In some embodiments, the surface treatment agent 202 may be a self-limiting layer. For example, as detailed below, in some embodiments, when element 201 is mixed with surfactant element 210 in a solvent to form a slurry, the surface treatment agent 202 layer self-assembles on the surface by electrostatic interactions between elements 201 and 210 in the slurry. In some such embodiments, when a region of the surface of element 201 is covered with surfactant element 210, additional surfactant elements 210 will not be attracted to that region. In some embodiments, when the surface of element 201 is covered with surfactant element 202, further elements are repelled from the layer, resulting in a self-limiting process. For example, in some embodiments, the surface treatment agent 202 may be formed by a self-limiting process, thereby ensuring that the layer is thin, e.g., the thickness of a single molecule or a few molecules.

[0032] In some embodiments, at least some of the hydrophilic ends 212 of the surfactant element form bonds with the active material particles 300. Thus, the surface treatment agent 202 can provide good adhesion between the elements 201 of the network 200 and the active material particles. In some embodiments, the bonds may be covalent bonds or non-covalent bonds such as π-π bonds, hydrogen bonds, electrostatic bonds, or combinations thereof.

[0033] For example, in some embodiments, the hydrophilic end 212 of the surfactant element 210 has a polar charge of a first polarity, while the surface of the active material particle 300 has a polar charge of a second polarity opposite to that of the first polarity, and therefore they are attracted to each other.

[0034] For example, in some embodiments in which, during the formation of layer 100, active material particles 300 are combined in a solvent with carbon elements 201 supporting a surface treatment agent 202 (as will be described in more detail below), the outer surface of the active material particles 300 may be characterized by a zeta potential having the opposite sign to the zeta potential of the outer surface of the surface treatment agent 202 (as is known in the art). Thus, in some such embodiments, the attractive force between the carbon elements 201 supporting the surface treatment agent 202 and the active material product 300 promotes the self-assembly of a structure in which the active material particles 300 are entangled with the carbon elements 201 of the network 200.

[0035] In some embodiments, at least some of the hydrophilic ends 212 of the surfactant element form a bond with the current collector layer or adhesive layer beneath the active material layer 100. Thus, the surface treatment agent 202 can provide good adhesion between the elements 201 of the network 200 and such underlying layers. In some embodiments, the bond may be a covalent bond or a non-covalent bond such as a π-π bond, hydrogen bond, electrostatic bond, or a combination thereof. In some embodiments, this arrangement provides excellent mechanical stability of the electrode 10, as will be discussed in more detail below.

[0036] In various embodiments, the surfactant used to form the surface treatment agent 202 described above may include any suitable material. For example, in some embodiments, the surfactant may include one or more of the following: hexadecyltrimethylammonium hexafluorophosphate (CTAP), hexadecyltrimethylammonium tetrafluoroborate (CTAB), hexadecyltrimethylammonium acetate, hexadecyltrimethylammonium nitrate, hocamidopropyl betaine, N-(cocoalkyl)-N,N,N-trimethylammonium methyl sulfate, and cocamidopropyl betaine. Additional suitable materials are described below.

[0037] In some embodiments, the surfactant layer 202 may be formed by dissolving a compound in a solvent such that the surfactant layer is formed from ions from the compound (e.g., by a self-limiting process as described above). In some such embodiments, the active layer 100 would contain residual counterions 214 to the surfactant ions that then form the surface treatment agent 202.

[0038] In some embodiments, these surfactant counterions 214 are selected to be suitable for use in an electrochemical cell. For example, in some embodiments, the counterions are selected to be non-reactive or mildly reactive with materials used in the cell, such as electrolytes, separators, and housings. For example, if an aluminum housing is used, the counterions may be selected to be non-reactive or mildly reactive with the aluminum housing.

[0039] For example, in some embodiments, the residual counterions do not contain or substantially contain halide groups. For example, in some embodiments, the residual counterions do not contain or substantially contain bromine.

[0040] In some embodiments, the residual counterion may be selected to match the electrolyte used in the energy storage cell containing the active layer 200. For example, in some embodiments, the residual counterion may be the same type of ion used within the electrolyte itself. For example, if the electrolyte contains a dissolved LiPF6 salt, the electrolyte anion is PF6. In such a case, the surfactant may be selected, for example, as CTA PF6, such that the surface treatment agent 202 is formed as a layer of anions from CTA PF6, while the residual surfactant counterion is the PF6 anion from CTA PF6 (and thus matches the anion of the electrolyte).

[0041] In some embodiments, the surfactant material used may be soluble in a solvent exhibiting favorable properties. For example, in some embodiments, the solvent may include water, or alcohols such as methanol, ethanol, or 2-propanol (sometimes referred to as isopropyl alcohol, IPA), or a combination thereof. In some embodiments, the solvent may include one or more additives used to further improve the properties of the solvent, such as low-boiling point additives such as acetonitrile (ACN), deionized water, and tetrahydrofuran.

[0042] For example, if a low-boiling point solvent is used to form the surface treatment agent 202, the solvent can be rapidly removed using a thermal drying process (e.g., of the type described in more detail below) carried out at a relatively low temperature. As will be understood by those skilled in the art, this can improve the speed and / or cost of manufacturing the active layer 202.

[0043] For example, in some embodiments, the surface treatment agent 202 is formed from a material that is soluble in solvents having a boiling point of less than 250°C, 225°C, 202°C, 200°C, 185°C, 180°C, 175°C, 150°C, 125°C, or below, for example, 100°C or less.

[0044] In some embodiments, the solvent may exhibit other advantageous properties. In some embodiments, the solvent may have a low viscosity, such as a viscosity of 3.0 centipoise or less, 2.5 centipoise, 2.0 centipoise, 1.5 centipoise, or less at 20°C. In some embodiments, the solvent may have a low surface tension, such as a surface tension of 40 mN / m or less, 35 mN / m, 30 mN / m, or 25 mN / m or less at 20°C. In some embodiments, the solvent may have low toxicity, such as toxicity comparable to that of an alcohol, such as isopropyl alcohol.

[0045] Notably, this is in contrast to the conventional processes used to form electrode active layers, which feature bulk binder materials such as polyvinylidene fluoride or polyvinylidene difluoride (PVDF). Such bulk binders require aggressive solvents, often characterized by high boiling points. One such example is n-methyl-2-pyrrolidone (NMP). The use of NMP (or other pyrrolidone-based solvents) as a solvent requires the use of high-temperature drying processes to remove the solvent. Furthermore, NMP is expensive, requires complex solvent recovery systems, is highly toxic, and poses significant safety problems. In contrast, in various embodiments, as will be described in more detail below, the active layer 200 can be formed without using NMP or similar compounds, such as pyrrolidone compounds.

[0046] While an exemplary surface treatment agent 202 of one class is described above, it is understood that other treatments may be used. For example, in various embodiments, the surface treatment agent 202 may be formed by functionalizing high aspect ratio carbon elements 201 using any suitable techniques described herein or known in the art. The functional groups applied to the elements 201 may be selected to promote adhesion between the active material particles 300 and the network 200. For example, in various embodiments, the functional groups may include carboxyl groups, hydroxyl groups, amine groups, silane groups, or combinations thereof.

[0047] As will be described in more detail below, in some embodiments, the functionalized carbon element 201 is formed from a dry (e.g., freeze-dried) aqueous dispersion comprising nanoform carbon and a functionalizing material such as a surfactant. In some such embodiments, the aqueous dispersion is substantially free of materials that would damage the carbon element 201, such as acids.

[0048] Referring to Figure 3, in some embodiments, the surface treatment agent 202 on the high aspect ratio carbon element 201 includes a thin polymer layer disposed on the carbon element that promotes adhesion of the active material to the network. In some such embodiments, the thin polymer layer includes a self-assembling and / or self-limiting polymer layer. In some embodiments, the thin polymer layer is bonded to the active material, for example, via hydrogen bonds.

[0049] In some embodiments, the thin polymer layer may have a thickness perpendicular to the outer surface of the carbon element that is less than 3, 2, 1, 0.5, 0.1 (or less) of the small dimensions of element 201.

[0050] In some embodiments, the thin polymer layer includes functional groups (e.g., side functional groups) that bond to the active material via non-covalent bonds, such as π-π bonds. In some such embodiments, the thin polymer layer can form a stable coating layer over at least a portion of element 201.

[0051] In some embodiments, a thin polymer layer on some of the element 201 may bond to the current collector 101 or adhesive layer 102 located beneath the active layer 200. For example, in some embodiments, the thin polymer layer includes side functional groups that bond to the surface of the current collector 101 or adhesive layer 102 via non-covalent bonds, such as π-π bonds. In some such embodiments, the thin polymer layer may form a stable coating layer over at least a portion of the element 201. In some embodiments, this arrangement provides excellent mechanical stability of the electrode 10, as will be discussed in more detail below.

[0052] In some embodiments, the polymer material is miscible in solvents of the types described in the examples above. For example, in some embodiments, the polymer material is miscible in solvents containing alcohols such as methanol, ethanol, or 2-propanol (sometimes referred to as isopropyl alcohol, IPA), or combinations thereof. In some embodiments, the solvent may contain one or more additives used to further improve the properties of the solvent, such as low-boiling point additives such as acetonitrile (ACN), deionized water, and tetrahydrofuran.

[0053] Suitable examples of materials that can be used to form a polymer layer include water-soluble polymers such as polyvinylpyrrolidone. Additional exemplary materials are provided below.

[0054] In some embodiments, the polymer material may have a low molecular weight, for example, 1,000,000 g / mol or less, 500,000 g / mol, 100,000 g / mol, 50,000 g / mol, 5,000 g / mol, or 2,500 g / mol or less.

[0055] It should be noted that the thin polymer layer described above is qualitatively different from the bulk polymer binders used in conventional electrodes. Rather than filling a significant portion of the volume of the active layer 100, the thin polymer layer resides on the surface of the high aspect ratio carbon elements, leaving most of the voids within the available network 200 to hold the active material particles 300.

[0056] For example, in some embodiments, the thin polymer layer has a maximum thickness perpendicular to the outer surface of the network, along the small dimensions of the carbon element 201, such as 1x, 0.5x, 0.25x, or less. For example, in some embodiments, the thin polymer layer may be as thin as a few molecules (e.g., 100, 50, 10, 5, 4, 3, 2, or even less than 1 molecule). Thus, in some embodiments, the thin polymer layer fills less than 10%, 5%, 1%, 0.1%, 0.01%, or 0.001% of the volume of the active layer 100.

[0057] In further exemplary embodiments, the surface treatment agent 202 may form a layer of carbonaceous material resulting from the thermal decomposition of a polymer material disposed on a high aspect ratio carbon element 201. This layer of carbonaceous material (e.g., graphite or amorphous carbon) may adhere to the active material particles 300 (e.g., via covalent bonds) or otherwise facilitate adhesion with the active material particles 300. An example of a suitable thermal decomposition technique is described in U.S. Patent Application No. 63 / 028982, filed May 22, 2020. One polymer material suitable for use in this technique is polyacrylonitrile (PAN).

[0058] In various embodiments, the active material particles 300 may include any active material suitable for use in energy storage devices, including metal oxides such as lithium metal oxide. For example, the active material particles 300 may include lithium cobalt oxide (LCO, sometimes called "lithium cobaltate" or "lithium cobaltite," a compound in which one variation of the possible formulation is LiCoO2), lithium nickel manganese cobalt oxide (NMC, having the variation LiNiMnCo), lithium manganese oxide (LMO, having variations such as LiMn2O4, Li2MnO3), lithium nickel cobalt aluminum oxide (LiNiCoAlO2, and its variation as NCA), and lithium titanate oxide (LTO, one variation of which is Li4Ti5O 12), lithium iron phosphate oxide (LFP, one variant being LiFePO4), lithium nickel cobalt aluminum oxide (and its variant as NCA), and other similar materials may be included. The other variants described above may be included.

[0059] In some embodiments where NMC is used as the active material, nickel-rich NMC may be used. For example, in some embodiments, a variant of NMC may be LiNi x Mn y Co 1-x-y where x may be about 0.7, 0.75, 0.80, 0.85, or more. In some embodiments, so-called NMC811 may be used, where in the above formula, x is about 0.8 and y is about 0.1.

[0060] In some embodiments, the active material may include other forms of lithium nickel manganese cobalt oxide (LiNi x Mn y Co z O2). For example, without limitation, common variants such as the following, namely, NMC 111 (LiNi 0.33 Mn 0.33 Co 0.33 O2), NMC 532 (LiNi 0.5 Mn 0.3 Co 0.2 O2), NMC 622 (LiNi 0.6 Mn 0.2 Co 0.2 O2), etc. may be used.

[0061] In some embodiments, for example, when the electrode is used as the negative electrode, the active material may include graphite, hard carbon, activated carbon, nanofoam carbon, silicon, silicon oxide, carbon-encapsulated silicon nanoparticles. In some such embodiments, the active layer 100 may be intercalated with lithium using, for example, prelithiation methods known in the art. ​​In some embodiments, the techniques described herein may enable the active layer 100 to be fabricated with a large proportion of the material in the active layer, e.g., more than 75% by weight, 80% by weight, 85% by weight, 90% by weight, 95% by weight, 99% by weight, 99.5% by weight, 99.8% by weight or more, while still exhibiting excellent mechanical properties (e.g., no peeling during operation in the type of energy storage device described herein). For example, in some embodiments, the active layer may have such high amounts of active material and large thickness (e.g., more than 50 μm, 100 μm, 150 μm, 200 μm, or more), while still exhibiting excellent mechanical properties (e.g., no peeling during operation in the type of energy storage device described herein).

[0063] The active material particles 201 within the active layer 100 may be characterized by median particles sized to, for example, 0.1 μm to 50 micrometers μm, or any sub-range thereof. The active material particles 201 within the active layer 100 may be characterized by a particle size distribution that is unimodal, bimodal, or multimodal. The active material particles 201 have a particle size of 0.1 square meters (m²) per gram. 2 ( / g) and 100 square meters (m) per gram 2 The specific surface area may be in the range of / g) or any sub-range thereof.

[0064] In some embodiments, the active layer 100 contains, for example, at least 20 mg / cm³. 2 , 30 mg / cm³ 2 , 40 mg / cm³ 2 , 50 mg / cm³ 2 , 60 mg / cm³ 2 70 mg / cm³ 2 , 80 mg / cm³ 2 90 mg / cm³ 2 , 100 mg / cm³ 2 It may have a mass load of 300 active material particles, or more than that.

[0065] Referring to Figure 4, an electron microscope image of an exemplary active material layer of the type described herein is shown. It is clearly shown that vine-like high aspect ratio carbon elements 201 (formed from a bundle of CNTs) are intertwined with the active material particles 300. Note that there is no bulky polymer material occupying space within the layer.

[0066] Energy storage cell Referring to Figure 5, an energy storage cell 500 is shown, comprising a first electrode 501, a second electrode 502, a permeable separator 503 disposed between the first electrode 501 and the second electrode 502, and an electrolyte 504 for wetting the first and second electrodes. One or both of electrodes 501 and 502 may be of the type described herein.

[0067] In some embodiments, the energy storage cell 500 may be a battery such as a lithium-ion battery. In some such embodiments, the electrolyte may be, for example, a lithium salt dissolved in a solvent of the type described in Qi Li, Juner Chen, Lei Fan, Xueqian Kong, Yingying Lu, Progress in electrolytes for rechargeable Li-based batteries and beyond, Green Energy & Environment, Volume 1, Issue 1, Pages 18-42, which is incorporated herein by reference.

[0068] In some such embodiments, the energy storage cell may have an operating voltage in the range of 1.0V to 5.0V, or any sub-range thereof, for example, 2.3V to 4.3V.

[0069] In some such embodiments, the energy storage cell 500 may have an operating temperature range including -40°C to 100°C, or any sub-range thereof, such as -10°C to 60°C.

[0070] In some such embodiments, the energy storage cell 500 may have a gravimetric energy density of at least 100 Wh / kg, 200 Wh / kg, 300 Wh / kg, 400 Wh / kg, 500 Wh / kg, or 1000 Wh / kg or more.

[0071] In some such embodiments, the energy storage cell 500 may have a volumetric energy density of at least 200 Wh / L, 400 Wh / L, 600 Wh / L, 800 Wh / L, 1,000 Wh / L, 1,500 Wh / L, or 2,000 Wh / L or more.

[0072] In some such embodiments, the energy storage cell 500 may have a C rate in the range of 0.1 to 50.

[0073] In some such embodiments, the energy storage cell 500 may have a cycle life of at least 1,000, 1,500, 2,000, 2,500, 3,000, 3,500, or 4,000 or more charge-discharge cycles.

[0074] In some embodiments, the energy storage cell 500 may be a lithium-ion capacitor of the type described in U.S. Patent Application No. 63 / 021492, filed 8 May 2020, which is incorporated herein by reference.

[0075] In some such embodiments, the energy storage cell 500 may have an operating temperature range including -60°C to 100°C, or any sub-range thereof, such as -40°C to 85°C.

[0076] In some such embodiments, the energy storage cell 500 may have a gravimetric energy density of at least 10 Wh / kg, 15 Wh / kg, 20 Wh / kg, 30 Wh / kg, 40 Wh / kg, 50 Wh / kg, or more.

[0077] In some such embodiments, the energy storage cell 500 may have a volumetric energy density of at least 20 Wh / L, 30 Wh / L, 40 Wh / L, 50 Wh / L, 60 Wh / L, 70 Wh / L, or 80 Wh / L or more.

[0078] In some such embodiments, the energy storage cell 500 may have a gravimetric power density of at least 5 kW / kg, 7.5 W / kg, 10 kW / kg, 12.5 kW / kg, 14 kW / kg, or 15 kW / kg.

[0079] In some such embodiments, the energy storage cell 500 may have a volumetric power density of at least 10 kW / L, 15 kW / L, 20 kW / L, 22.5 kW / L, 25 kW / L, 28 kW / L, or 30 kW / L or more.

[0080] In some such embodiments, the energy storage cell 500 may have a C rate in the range of 1.0 to 100.

[0081] In some such embodiments, the energy storage cell 500 may have a cycle life of at least 100,000, 500,000, or 1,000,000 or more charge-discharge cycles.

[0082] Manufacturing method The electrode 10, characterized by the active layer 100 as described herein, may be manufactured using any preferred manufacturing process. As will be understood by those skilled in the art, in some embodiments, the electrode 10 may be manufactured using a wet coating technique of the type described in International Patent Publication No. 2018 / 102652, published on June 7, 2018, in further consideration of the teachings described herein.

[0083] Referring to Figure 6, in some embodiments, the active layer 100 of the electrode 10 may be formed using method 1000. In step 1001, high aspect ratio carbon elements 201 and a surface treatment agent material (e.g., a surfactant or polymer material as described herein) are combined with a solvent (of the type described herein) to form an initial slurry.

[0084] In step 1002, the initial slurry is treated to ensure good dispersion of the solid material in the slurry. In some embodiments, this treatment involves introducing mechanical energy into the mixture of solvent and solid material (e.g., using a sonicator, sometimes also referred to as a "sonifier") or other suitable mixing device (e.g., a high-shear mixer). In some embodiments, the mechanical energy introduced into the mixture is at least 0.4 kilowatt-hours / 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 may be in the range of 0.4 kWh / kg to 1.0 kWh / kg, or any sub-range thereof, e.g., 0.4 kWh / kg to 0.6 kWh / kg.

[0085] In some embodiments, an ultrasonic bath mixer may be used. In other embodiments, a probe sonicator may be used. Probe sonication can be significantly more powerful and effective compared to ultrasonic baths for nanoparticle applications. The high force generated by ultrasonic cavitation has the ability to break down particle aggregates, resulting in smaller and more uniform particle sizes. In particular, sonication can result in a stable and homogeneous suspension of solids in a slurry. Generally, this results in the dispersion and de-aggregation of solids, as well as other decompositions. An example of a probe sonication device is the Q Series Probe Sonicator, available from QSonica LLC in Newtown, Connecticut. Another example is the Branson Digital SFX-450 sonicator, commercially available from Thomas Scientific in Swesboro, New Jersey.

[0086] However, in some embodiments, the localization of each probe within the probe assembly can lead to heterogeneous mixing and suspension. This can be true, for example, with larger samples. This can be addressed by using a setup with a continuous flow cell and proper mixing. That is, mixing the slurry in such a setup will achieve a reasonably homogeneous dispersion.

[0087] In some embodiments, once processed, the initial slurry will have a viscosity in the range of 5,000 cps to 25,000 cps, or any sub-range thereof, for example, 6,000 cps to 19,000 cps.

[0088] In step 1003, the surface treatment agent 202 may be fully or partially formed on the high aspect ratio carbon elements 201 in the initial slurry. In some embodiments, at this stage, the surface treatment agent 202 may self-assemble as described in detail above with reference to Figures 2 and 3. The resulting surface treatment agent 201 may contain functional groups or other features that can promote adhesion between the high aspect ratio carbon elements 201 and the active material particles 300, as described in the following further steps.

[0089] In step 1004, the active material particles 300 are combined with the initial slurry to form a final slurry containing the active material particles 300 together with high aspect ratio carbon elements 201 on which a surface treatment agent 202 is formed.

[0090] In some embodiments, the active material 300 may be added directly to the initial slurry. In other embodiments, the active material 300 may first be dispersed in a solvent (for example, using the techniques described above with respect to the initial solvent) to form an active material slurry. This active material slurry may then be combined with the initial slurry to form the final slurry.

[0091] In step 1005, the final slurry is processed to ensure good dispersion of solid materials within the final slurry. In various embodiments, any suitable mixing process known in the art may be used. In some embodiments, this processing may use the techniques described above with respect to step 1002. In some embodiments, a planetary mixer, such as a multi-axis (e.g., three or more axes) planetary mixer, may be used. In some such embodiments, the planetary mixer may feature a plurality of blades, e.g., two or more mixing blades and one or more (e.g., two, three, or more) dispersion blades, such as disk dispersion blades.

[0092] In some embodiments, during step 1005, the matrix 200 intertwined with the active material 300 may self-assemble completely or partially, as described in detail above with respect to Figures 2 and 3. In some embodiments, the interaction between the surface treatment agent 202 and the active material 300 facilitates the self-assembly process.

[0093] In some embodiments, the final slurry, once processed, will have a viscosity in the range of 1,000 cps to 10,000 cps, or any sub-range thereof, for example, in the range of 2,500 cps to 6,000 cps.

[0094] In step 1006, the active layer 100 is formed from the final slurry. In some embodiments, the final slurry may be cast directly onto the current collector conductive layer 101 (or an optional adhesive layer 102) in a wet state and then dried. As an example, casting may be performed by applying at least one of heat and vacuum until substantially all of the solvent and any other liquids are removed, thereby forming the active layer 100. In some such embodiments, it may be desirable to protect various parts of the underlying layer. For example, if the electrode 10 is intended for bidirectional operation, it may be desirable to protect the underside of the conductive layer 101. Protection may include protection from the solvent, for example, by masking specific areas or by providing drains to guide the solvent away.

[0095] In other embodiments, the final slurry may be at least partially dried elsewhere using any preferred technique (e.g., roll-to-roll layer application) and then transferred onto the adhesive layer 102 or the conductive layer 101 to form the active layer 100. In some embodiments, the wet mixed slurry may be placed on an intermediate material having a suitable surface and dried to form a layer (i.e., the active layer 100). Any material having a suitable surface can be used as the intermediate material, but an exemplary intermediate material is PTFE, as its properties facilitate subsequent removal from the surface. In some embodiments, the designated layer is formed by pressing to provide a layer exhibiting a desired thickness, area, and density.

[0096] In some embodiments, the final slurry is formed in a sheet and, if necessary, coated onto the adhesive layer 102 or the conductive layer 101. For example, in some embodiments, the final slurry may be applied through a slot die to control the thickness of the applied layer. In other embodiments, for example, the slurry may be applied using a doctor blade and then flattened to a desired thickness. Various other techniques may be used to apply the slurry. For example, coating techniques may 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, single roll kiss coating, reverse kiss coating with small diameter gravure rolls, bar coating, triple reverse roll coating (top feed), triple reverse roll coating (fountain die), reverse roll coating, and the like.

[0097] The viscosity of the final slurry can vary depending on the applied technology. For example, in the case of comma coating, the viscosity may range from approximately 1,000 cps to approximately 200,000 cps. Lip die coating provides coating with a slurry exhibiting a viscosity of approximately 500 cps to approximately 300,000 cps. Reverse kiss coating provides coating with a slurry exhibiting a viscosity of approximately 5 cps to 1,000 cps. In some applications, each layer may be formed by multiple passes.

[0098] In some embodiments, the active layer 100 formed from the final slurry can be compressed (e.g., using a calendering device) before or after it is applied to the electrode 10. In some embodiments, the slurry can be partially or completely 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 (e.g., in the direction perpendicular to the current collector layer 101) of less than 90%, 80%, 70%, 50%, 40%, 30%, 20%, or 10% of its thickness before compression.

[0099] In various embodiments, once a partially dried layer is formed during the coating or compression process, the layer can then be completely dried (for example, by applying heat, vacuum, or a combination thereof). In some embodiments, substantially all of the solvent is removed from the active layer 100.

[0100] In some embodiments, the solvent used to form the slurry is recovered and recycled into the slurry preparation process.

[0101] In some embodiments, the active layer may be compressed to increase the surface area of ​​each layer, for example, by breaking down some of the high aspect ratio carbon elements or other carbonaceous materials of the component. In some embodiments, this compression treatment may increase one or more of the following: interlayer adhesion, intralayer ion transport rate, and layer surface area. In various embodiments, compression may be applied before or after each layer is coated onto or formed on the electrode 10.

[0102] In some embodiments where calendering is used to compress the active layer 100, the calendering apparatus may be set with gap spacings equal to less than 90%, 80%, 70%, 50%, 40%, 30%, 20%, and 10% of the pre-compression thickness of the layer (for example, set to about 33% of the pre-compression thickness of the layer). The calender roll may be configured to provide a suitable pressure, for example, more than 1 ton per 1 cm of roll length, more than 1.5 tons per 1 cm of roll length, more than 2.0 tons per 1 cm of roll length, more than 2.5 tons per 1 cm of roll length, or greater. In some embodiments, the compressed active layer will have a density in the range of 1 g / cc to 10 g / cc, or any sub-range thereof, for example, 2.5 g / cc to 4.0 g / cc. In some embodiments, calendering may be performed at a temperature in the range of 20°C to 140°C, or any sub-range thereof. In some embodiments, the active layer may be preheated before calendering at a temperature in the range of 20°C to 100°C, or any sub-range thereof.

[0103] Once the electrodes 10 are assembled, the energy storage device 10 can be assembled using the electrodes 100. The assembly of the energy storage device 10 may follow conventional processes used to assemble the electrodes using separators and place them in a housing such as a canister or pouch, and may also include additional steps for electrolyte addition and sealing of the housing.

[0104] In various embodiments, process 1000 may include any of the following features (individually or in any preferred combination):

[0105] In some embodiments, the initial slurry has a solid content ranging from 0.1% to 20.0% by weight (or any sub-range). In some embodiments, the final slurry has a solid content ranging from 10.0% to 80% by weight (or any sub-range).

[0106] In various embodiments, the solvent used may be any of the solvents described herein with respect to the formation of the surface treatment agent 202. In some embodiments, the surfactant material used to form the surface treatment agent 202 may be soluble in a solvent exhibiting favorable properties. For example, in some embodiments, the solvent may include water, or an alcohol such as methanol, ethanol, or 2-propanol (isopropyl alcohol, sometimes referred to as IPA), or a combination thereof. In some embodiments, the solvent may include one or more additives used to further improve the properties of the solvent, such as low-boiling point additives such as acetonitrile (ACN), deionized water, and tetrahydrofuran.

[0107] In some embodiments, when a low-boiling point solvent is used, the solvent can be rapidly removed using a thermal drying process performed at relatively low temperatures. As will be understood by those skilled in the art, this can improve the speed and / or cost of manufacturing the electrode 10. For example, in some embodiments, the solvent may have a boiling point of less than 250°C, 225°C, 202°C, 200°C, 185°C, 180°C, 175°C, 150°C, 125°C, or below, for example, 100°C or less.

[0108] In some embodiments, the solvent may exhibit other advantageous properties. In some embodiments, the solvent may have a low viscosity, such as a viscosity at 20°C of 3.0 centipoise or less, 2.5 centipoise, 2.0 centipoise, 1.5 centipoise, or less. In some embodiments, the solvent may have a low surface tension, such as a surface tension at 20°C of 40 mN / m or less, 35 mN / m, 30 mN / m, or 25 mN / m. In some embodiments, the solvent may have low toxicity, such as toxicity comparable to that of an alcohol, such as isopropyl alcohol.

[0109] In some embodiments, during the formation of the active layer, the material forming the surface treatment agent may be dissolved in a solvent that is substantially free of pyrrolidone compounds. In some embodiments, the solvent is substantially free of n-methyl-2-pyrrolidone.

[0110] In some embodiments, the surface treatment agent 201 is formed from a material comprising a surfactant of the type described herein.

[0111] In some embodiments, forming an initial slurry by dispersing high aspect ratio carbon elements and surface treatment agent materials in a solvent involves applying force to the aggregated carbon elements to slide them away from each other along a direction perpendicular to the minor axis of the elements. In some embodiments, techniques for forming such dispersions may be adapted from those disclosed in International Patent Publication No. 2018 / 102652, published on June 7, 2018, with further consideration given to the teachings described herein.

[0112] In some embodiments, the high aspect ratio carbon element 201 may be functionalized before forming the slurry used to form the electrode 10. For example, in one embodiment, a method is disclosed in which the high aspect ratio carbon element 201 and a surface treatment agent material are dispersed in an aqueous solvent to form an initial slurry, the dispersion step of which includes dispersing, resulting in the formation of a surface treatment agent on the high aspect ratio carbon, and drying the initial slurry to remove substantially all moisture to produce a dry powder of high aspect ratio carbon having the surface treatment agent on its surface. In some embodiments, the dry powder may be combined, for example, with a slurry of a solvent and an active material to form a final solvent of the type described above with respect to Method 1000.

[0113] In some embodiments, drying the initial slurry includes lyophilizing (freeze-drying) the initial slurry. In some embodiments, the aqueous solvent and initial slurry are substantially free of substances that damage the high aspect ratio carbon elements. In some embodiments, the aqueous solvent and initial slurry are substantially free of acid. In some embodiments, the initial slurry essentially consists of high aspect ratio carbon elements, a surface treatment agent material, and water.

[0114] Some embodiments further include dispersing a dry powder of high aspect ratio carbon together with a surface treatment agent in a solvent, and adding an active material to form a secondary slurry, coating the secondary slurry onto a substrate, and drying the secondary slurry to form an electrode active layer. In some embodiments, the steps described above may be carried out using techniques adapted from those disclosed in International Patent Publication 2018 / 102652, published on June 7, 2018, with further consideration to the teachings described herein.

[0115] In some embodiments, the final slurry may contain polymer additives such as polyacrylic acid (PAA), poly(vinyl alcohol) (PVA), poly(vinyl acetate) (PVAc), polyacrylonitrile (PAN), polyisoprene (PIpr), polyaniline (PANi), polyethylene (PE), polyimide (PI), polystyrene (PS), polyurethane (PU), polyvinyl butyral (PVB), and polyvinylpyrrolidone (PVP). In some embodiments, the active layer may be treated by applying heat to decompose the additives so that the surface treatment agent 202 can form a layer of carbonaceous material resulting from the thermal decomposition of the polymer additives. This layer of carbonaceous material (e.g., graphite or amorphous carbon) may adhere to the active material particles 300 (e.g., via covalent bonds) or otherwise facilitate adhesion with the active material particles 300. The heat treatment may be applied by any preferred means, for example, by the application of a laser beam. An example of a suitable pyrolysis technique is described in U.S. Patent Application No. 63 / 028982, filed on 22 May 2020.

[0116] surfactants The above-described technique involves the use of a surfactant for a surface treatment agent 202 on high aspect ratio carbon nanotubes 201 to promote adhesion with the active material particles 300. While several advantageously suitable surfactants are described, it should be understood that other surfactant materials may be used, including the following:

[0117] Surfactants are molecules or groups of molecules that have surface activity, such as wetting agents, dispersants, emulsifiers, detergents, and foaming agents. Various surfactants can be used in the preparation of surface treatment agents as described herein. Typically, the surfactants used contain lipophilic nonpolar hydrocarbon groups and polar functional hydrophilic groups. Polar functional groups may be carboxylates, esters, amines, amides, imides, hydroxyls, ethers, nitriles, phosphates, sulfates, or sulfonates. Surfactants can be used alone or in combination. Thus, combinations of surfactants may include anionic, cationic, nonionic, amphoteric, amphoteric, and ampholytic surfactants, as long as a net positive or negative charge exists in the head region of the population of surfactant molecules. In some cases, a single negatively or positively charged surfactant is used in the preparation of the electrode composition.

[0118] The surfactants used in the preparation of this electrode composition may be anionic, but are not limited to, alkyl sulfonates, alkylbenzene sulfonates, alpha-olefin sulfonates, paraffin sulfonates, and alkyl ester sulfonates; sulfates such as alkyl sulfates, alkyl alkoxy sulfates, and alkyl alkoxylated sulfates; phosphates such as monoalkyl phosphates and dialkyl phosphates; phosphonates; fatty acids; alkyl alkoxy carboxylates; sarcosinates; isethionates; and carboxylates such as taurates. Specific examples of carboxylates include sodium oleate, sodium cocoyl isethionate, sodium methyl oleoyl taurate, sodium laureth carboxylate, sodium trideceth carboxylate, sodium lauryl sarcosinate, lauroyl sarcosine, and cocoyl sarcosinate. Specific examples of sulfates include sodium dodecyl sulfate (SDS), sodium lauryl sulfate, sodium laureth sulfate, sodium trideceth sulfate, sodium tridecyl sulfate, sodium cocyl sulfate, and sodium lauric acid monoglyceride sulfate.

[0119] Suitable sulfonate surfactants include, but are not limited to, alkyl sulfonates, aryl sulfonates, monoalkyl and dialkyl sulfosuccinates, and monoalkyl and dialkyl sulfosuccinates. Each alkyl group independently contains about 2 to 20 carbon atoms, and each alkyl group can be ethoxylated with up to about 8 units, preferably up to about 6 units, on average, for example, 2, 3, or 4 units of ethylene oxide. Exemplary examples of alkyl and aryl sulfonates are sodium tridecylbenzenesulfonate (STBS) and sodium dodecylbenzenesulfonate (SDBS).

[0120] Examples of sulfosuccinates include, but are not limited to, dimethicone copolyol sulfosuccinate, diamyl sulfosuccinate, dicapryl sulfosuccinate, dicyclohexyl sulfosuccinate, diheptyl sulfosuccinate, dihexyl sulfosuccinate, diisobutyl sulfosuccinate, dioctyl sulfosuccinate, C12-15 pareth sulfosuccinate, cetearyl sulfosuccinate, cocopolyglucose sulfosuccinate, cocoyl butyl gluceth-10 sulfosuccinate, deceth-5 sulfosuccinate, deceth-6 sulfosuccinate, dihydroxyethyl sulfosuccinyl undecylenate, hydrogenated cottonseed glyceride sulfosuccinate, and isodecyl sulfosuccinate. Examples include isostearyl sulfosuccinate, lanes-5 sulfosuccinate, laureth sulfosuccinate, laureth-12 sulfosuccinate, laureth-6 sulfosuccinate, laureth-9 sulfosuccinate, lauryl sulfosuccinate, nonoxynol-10 sulfosuccinate, oleth-3 sulfosuccinate, oleyl sulfosuccinate, PEG-10 lauryl citrate sulfosuccinate, cytocereth-14 sulfosuccinate, stearyl sulfosuccinate, taloupe, tridecyl sulfosuccinate, ditridecyl sulfosuccinate, bisglycol ricinosulfosuccinate, di(1,3-dimethylbutyl) sulfosuccinate, and silicone copolyol sulfosuccinate.

[0121] Exemplary examples of sulfosuccinates include, but are not limited to, lauramide-MEA sulfosuccinate, oleamide PEG-2 sulfosuccinate, cocamide MIPA sulfosuccinate, cocamide PEG-3 sulfosuccinate, isostearamid-MEA sulfosuccinate, isostearamid MIPA sulfosuccinate, lauramide-MEA sulfosuccinate, lauramide PEG-2 sulfosuccinate, lauramide PEG-5 sulfosuccinate, myristamide-MEA sulfosuccinate, oleamide-MEA sulfosuccinate, oleamide PIPA sulfosuccinate, oleamide PEG-2 sulfosuccinate Examples include rufosuccinate, palmitamide PEG-2 sulfosuccinate, palmitreamide PEG-2 sulfosuccinate, PEG-4 cocamide MIPA-sulfosuccinate, ricinoleamide MEA-sulfosuccinate, stearamide MEA-sulfosuccinate, stearyl sulfosuccinate, talamide MEA-sulfosuccinate, talo sulfosuccinate, taloamide MEA-sulfosuccinate, undecylenamide MEA-sulfosuccinate, undecylenamide PEG-2 sulfosuccinate, wheat germ amide MEA-sulfosuccinate, and wheat germ amide PEG-2 sulfosuccinate.

[0122] Some examples of commercially available sulfonates include AEROSOL® OT-S, AEROSOL® OT-MSO, AEROSOL® TR70% (Cytec Inc., West Patterson, New Jersey), NaSul CA-HT3 (King Industries, Norwalk, Connecticut), and C500 (Crompton Co., West Hill, Ontario, Canada). AEROSOL® OT-S is sodium dioctyl sulfosuccinate in a petroleum fraction. AEROSOL® OT-MSO also contains sodium dioctyl sulfosuccinate. AEROSOL® TR70% is sodium bistridecyl sulfosuccinate in a mixture of ethanol and water. NaSul CA-HT3 is a calcium dinonylnaphthalene sulfonate / carboxylate complex. C500 is oil-soluble calcium sulfonate.

[0123] Alkyl or alkyl refers to saturated hydrocarbons having one or more carbon atoms, including linear alkyl groups (e.g., methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, etc.), cyclic alkyl groups (or cycloalkyl or alicyclic or carbocyclic groups) (e.g., cyclopropyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, etc.), branched alkyl groups (e.g., isopropyl, tert-butyl, sec-butyl, isobutyl, etc.), and alkyl-substituted alkyl groups (e.g., alkyl-substituted cycloalkyl groups and cycloalkyl-substituted alkyl groups).

[0124] Alkyls can include both unsubstituted and substituted alkyls. A substituted alkyl refers to an alkyl group having substituents that replace one or more hydrogens on one or more carbons of a hydrocarbon skeleton. Examples of such substituents include alkenyl, alkynyl, halogeno, hydroxyl, alkylcarbonyloxy, arylcarbonyloxy, alkoxycarbonyloxy, aryloxy, aryloxycarbonyloxy, carboxylate, alkylcarbonyl, arylcarbonyl, alkoxycarbonyl, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, alkylthiocarbonyl, alkoxyl, phosphate, phosphonate, phosphinate, cyano, amino (including alkylamino, dialkylamino, arylamino, diarylamino, and alkylarylamino), acylamino (including alkylcarbonylamino, arylcarbonylamino, carbamoyl, and ureido), imino, sulfhydryl, alkylthio, arylthio, thiocarboxylate, sulfate, alkylsulfinyl, sulfonate, sulfamoyl, sulfonamide, nitro, trifluoromethyl, cyano, azide, heterocyclic, alkylaryl, or aromatic (including heteroaromatic) groups.

[0125] In some embodiments, substituted alkyl groups may include heterocyclic groups. Heterocyclic groups have a ring-closed structure similar to a carbocyclic group, where one or more of the carbon atoms in the ring are elements other than carbon, such as nitrogen, sulfur, or oxygen. Heterocyclic groups may be saturated or unsaturated. Exemplary heterocyclic groups include aziridine, ethylene oxide (epoxide, oxirane), thiirane (episulfide), dioxirane, azetidine, oxetane, thiethane, dioxetane, dithiethane, dithiethone, azolidine, pyrrolidine, pyrroline, oxolane, dihydrofuran, and furan.

[0126] In the case of anionic surfactants, the counterion is typically sodium, but can alternatively be potassium, lithium, calcium, magnesium, ammonium, amines (primary, secondary, tertiary, or quaternary), or other organic bases. Exemplary amines include isopropylamine, ethanolamine, diethanolamine, and triethanolamine. Mixtures of the above cations may also be used.

[0127] The surfactants used in the preparation of this material may be cationic. Examples of such cationic surfactants include, but are not limited to, pyridinium-containing compounds and primary, secondary, tertiary, or quaternary organic amines. In the case of cationic surfactants, the counterions may be, for example, chlorides, bromides, methosulfates, ethosulfates, lactates, saccharins, acetates, and phosphates. Examples of cationic amines include polyethoxylated oleyl / stearylamines, ethoxylated taloamines, cocoalkylamines, oleylamines, and taloalkylamines, as well as mixtures thereof.

[0128] Examples of quaternary amines having a single long-chain alkyl group include cetyltrimethylammonium bromide (CTAB), benzyldodecyldimethylammonium bromide (BddaBr), benzyldimethylhexadecylammonium chloride (BdhaCl), dodecyltrimethylammonium bromide, myristyltrimethylammonium bromide, stearyldimethylbenzylammonium chloride, oleyldimethylbenzylammonium chloride, lauryltrimethylammonium methosulfate (also known as cocotrimonium methosulfate), cetyldimethylhydroxyethylammonium dihydrogen phosphate, bassuamidopropylkonium chloride, cocotrimonium chloride, distearyldimonium chloride, wheat germ amide propalkonium chloride, and stearyloctyidimonium methosulfate. These include methosulfate, isostearaminopropal-konium chloride, dihydroxypropyl PEG-5 linoleammonium chloride, PEG-2 stearmonium chloride, behentrimonium chloride, dicetyldimonium chloride, talotrimonium chloride, and behenamidopropyl ethyldimonium ethosulfate.

[0129] Examples of quaternary amines having two long-chain alkyl groups include didodecyldimethylammonium bromide (DDAB), distearyldimonium chloride, dicetyldimonium chloride, stearyloctyldimonium methosulfate, dihydrogenated palmoylethylhydroxyethylmonium methosulfate, dipalmitoylethylhydroxyethylmonium methosulfate, dioleoylethylhydroxyethylmonium methosulfate, and hydroxypropylbisstearyldimonium chloride.

[0130] Examples of quaternary ammonium compounds that are imidazoline derivatives include isostearylbenzylimidonium chloride, cocoylbenzylhydroxyethylimidazolinium chloride, cocoylhydroxyethylimidazolinium PG-chloride phosphate, and stearylhydroxyethylimidonium chloride. Other heterocyclic quaternary ammonium compounds such as dodecylpyridinium chloride, amprolium hydrochloride (AH), and benzethonium hydrochloride (BH) may also be used.

[0131] The surfactants used in the preparation of this material may be nonionic and include, but are not limited to, polyalkylene oxide carboxylic acid esters, fatty acid esters, fatty acid alcohols, ethoxylated fatty alcohols, poloxamers, alkanolamides, alkoxylated alkanolamides, polyethylene glycol monoalkyl ethers, and alkyl polysaccharides. Polyalkylene oxide carboxylic acid esters each have one or two carboxylic acid ester moieties having about 8 to 20 carbon atoms and a polyalkylene oxide moiety containing about 5 to 200 alkylene oxide units. Ethoxylated fatty alcohols contain an ethylene oxide moiety containing about 5 to 150 ethylene oxide units and a fatty alcohol moiety having about 6 to about 30 carbon atoms. The fatty alcohol moieties may be cyclic, linear, or branched and may be saturated or unsaturated. Some examples of ethoxylated fatty alcohols include ethylene glycol ethers of oleth alcohol, steareth alcohol, lauryl alcohol, and isocetyl alcohol. Poloxamers are ethylene oxide and propylene oxide block copolymers containing approximately 15 to 100 moles of ethylene oxide. Alkyl polysaccharide ("APS") surfactants (e.g., alkyl polyglycosides) contain a hydrophobic group with approximately 6 to 30 carbon atoms and a polysaccharide (e.g., polyglycoside) as a hydrophilic group. An example of a commercially available nonionic surfactant is FOA-5 (Octel Starreon LLC., Littleton, Colorado).

[0132] Specific examples of suitable nonionic surfactants include alkanolamides such as cocamide diethanolamide ("DEA"), cocamide monoethanolamide ("MEA"), cocamide monoisopropanolamide ("MIPA"), PEG-5 cocamide MEA, lauramide DEA, and lauramide MEA; alkylamine oxides such as lauramine oxide, cocamine oxide, cocamidopropylamine oxide, and lauramidopropylamine oxide; fatty acids or fatty acid esters such as sorbitan laurate, sorbitan distearate, lauric acid, isostearic acid, and PEG-150 distearate; fatty alcohols such as lauryl alcohol or ethoxylated fatty alcohols; and alkyl polyglucosides such as decyl glucoside, lauryl glucoside, and cocoglucoside.

[0133] The surfactants used in the preparation of this material may be amphoteric, possessing both formal positive and negative charges on the same molecule. The positively charged group may be a quaternary ammonium, phosphonium, or sulfonium, while the negatively charged group may be a carboxylate, sulfonate, sulfate, phosphate, or phosphonate. As with other classes of surfactants, the hydrophobic moiety may contain one or more long linear, cyclic, or branched aliphatic chains of about 8 to 18 carbon atoms. Specific examples of amphoteric surfactants include cocodimethylcarboxymethyl betaine, lauryldimethylcarboxymethyl betaine, lauryldimethylalphacarboxymethyl betaine, cetyldimethylcarboxymethyl betaine, laurylbis-(2-hydroxyethyl)carboxymethyl betaine, stearylbis-(2-hydroxypropyl)carboxymethyl betaine, oleyldimethylgamma-carboxypropyl betaine, and alkyl betaines such as laurylbis-(2-hydroxypropyl)alphacarboxyethyl betaine and amidopropyl betaine, as well as cocodimethylsulfopropyl betaine, stearyidimethylsulfopropyl betaine, lauryldimethylsulfoethyl betaine, laurylbis-(2-hydroxyethyl)sulfopropyl betaine, and alkylamidopropylsulfoxysultaine.

[0134] The surfactant used in the preparation of this material may be amphoteric. Examples of suitable amphoteric surfactants include alkylamphocarboxyglycinates and alkylamphocarboxypropionates, alkylamphodipropionates, alkylamphodiaacetates, alkylamphoglycinates, and alkylamphopropionates, as well as ammonium or substituted ammonium salts of alkyliminopropionates, alkyliminodipropionates, and alkylamphopropylsulfonates. Specific examples include cocoamphoacetate, cocoamphopropionate, cocoamphodiaacetate, lauroamphoacetate, lauroamphodiaacetate, lauroamphodipropionate, lauroamphodiaacetate, cocoamphopropylsulfonate, caproamphodiaacetate, caproamphoacetate, caproamphodipropionate, and stearoamphoacetate.

[0135] The surfactants used in the preparation of this material may be polymers such as N-substituted polyisobutenyl succinimide and succinate, alkyl methacrylate vinyl pyrrolidinone copolymer, alkyl methacrylate-dialkylaminoethyl methacrylate copolymer, alkyl methacrylate polyethylene glycol methacrylate copolymer, polystearamide, and polyethyleneimine.

[0136] The surfactant used in the preparation of this material may be a polysorbate-type nonionic surfactant such as polyoxyethylene (20) sorbitan monolaurate (Polysorbate 20), polyoxyethylene (20) sorbitan monopalmitate (Polysorbate 40), polyoxyethylene (20) sorbitan monostearate (Polysorbate 60), or polyoxyethylene (20) sorbitan monooleate (Polysorbate 80).

[0137] The surfactants used in the preparation of this material may be oil-based dispersants, including alkyl succinimides, succinate esters, high molecular weight amines, and Mannich bases and phosphate derivatives. Some specific examples are polyisobutenyl succinimide-polyethylene polyamine, polyisobutenyl succinate, polyisobutenyl hydroxybenzyl-polyethylene polyamine, and bis-hydroxypropyl phospholate.

[0138] The surfactants used in the preparation of this material may be a combination of two or more surfactants of the same or different types selected from the group consisting of anionic, cationic, nonionic, amphoteric, amphoteric, and ampholytic surfactants. Suitable examples of combinations of two or more surfactants of the same type include, but are not limited to, mixtures of two anionic surfactants, mixtures of three anionic surfactants, mixtures of four anionic surfactants, mixtures of two cationic surfactants, mixtures of three cationic surfactants, mixtures of four cationic surfactants, mixtures of two nonionic surfactants, mixtures of three nonionic surfactants, mixtures of four nonionic surfactants, mixtures of two amphoteric surfactants, mixtures of three amphoteric surfactants, mixtures of four amphoteric surfactants, mixtures of two amphoteric surfactants, mixtures of three amphoteric surfactants, mixtures of four amphoteric surfactants, mixtures of two ampholytic surfactants, mixtures of three ampholytic surfactants, and mixtures of four ampholytic surfactants.

[0139] Thin polymer layer material The above-described technique involves the use of a polymer to form a surface treatment agent 201 on high aspect ratio carbon nanotubes to promote adhesion with the active material particles 300. While several advantageously suitable polymers are described, it should be understood that other polymer materials, including the following, may be used.

[0140] The polymer used in the preparation of this material may be a polymer material such as a water-treated polymer material. In various embodiments, any of the following polymers (and combinations thereof) may be used, namely, polyacrylic acid (PAA), poly(vinyl alcohol) (PVA), poly(vinyl acetate) (PVAc), polyacrylonitrile (PAN), polyisoprene (PIpr), polyaniline (PANi), polyethylene (PE), polyimide (PI), polystyrene (PS), polyurethane (PU), polyvinyl butyral (PVB), and polyvinylpyrrolidone (PVP). In some embodiments, another exemplary polymer material is fluoroacrylic hybrid latex (TRD202A), supplied by JSR Corporation. [Examples]

[0141] The following non-limiting embodiments further illustrate the application of the teachings of this disclosure. In the following embodiments, the terms “binder-free” or “binderless” electrode refer to the type of electrode described in detail above, characterized by a 3D matrix or scaffold of high aspect ratio carbon having a surface treatment agent on its surface that promotes adhesion of the active material to the scaffold without requiring a bulk polymer binder such as PVDF.

[0142] Where used below, the term C-rate refers to a measure of the rate at which a battery discharges relative to its maximum capacity. A 1C rate means that the discharge current discharges the entire battery in one hour. For a battery with a capacity of 100 amp-hours, this is equivalent to a discharge current of 100 amps.

[0143] Example 1 - Battery cell for electric vehicle The following battery cells are suitable for use in electric vehicles ("EVs"). These cells combine the types of positive and negative electrode technologies described herein for use in EV applications, for example. Key high-level advantages include lower manufacturing costs, higher energy density, superior power density, and operation over a wide temperature range. These advantages stem from the approach to manufacturing the battery electrodes described herein, which eliminates the use of PVDF polymer binders and toxic solvents such as N-methyl-2-pyrrolidone (NMP). The result is a significant performance advantage for end-users in range, charging speed, and acceleration, and a lower-cost, less capital-intensive, and safer manufacturing process for battery producers.

[0144] The teachings herein provide a technical platform for manufacturing electrodes for energy storage that may exhibit the following advantages: reduced manufacturing costs and the $ / kWh of the resulting LIB, increased energy density by combining a cathode with a thick coating and a high-capacity anode featuring a high-performance active material such as Si or SiOx, and fast charging. The teachings herein also provide a scalable technique for improving power density in energy storage by removing conventional polymer binders from the active material coating.

[0145] Conventional LiB electrodes are manufactured by mixing an active material, conductive additives, and a polymer binder in a slurry. Conventional cathodes are manufactured using an NMP-based slurry and a PVDF polymer binder. These binders have very high molecular weights and promote aggregation of active material particles and adhesion to the current collector foil through two main mechanisms: 1) entanglement facilitated by long polymer chains, and 2) hydrogen bonding between the polymer, active material, and current collector. However, polymer binder-based methods exhibit significant drawbacks in performance, namely power density, energy density, and manufacturing cost.

[0146] The teachings herein provide electrodes that do not have a PVDF binder in the positive electrode or other conventional binders in the negative electrode. Instead, as detailed above, a 3D carbon scaffold or matrix forms an aggregated layer that holds active material particles together and adheres strongly to the metal current collector. Such an active material structure is fabricated during slurry preparation and subsequent roll-to-roll ("R2R") coating and drying processes. One of the main advantages of this technology is its scalability and "drop-in" nature, as it is compatible with conventional electrode manufacturing processes.

[0147] The 3D carbon matrix is ​​formed during slurry preparation using the techniques described herein, and the high aspect ratio carbon material is appropriately dispersed and chemically functionalized using, for example, a two-step slurry preparation process (such as the type described above with reference to Figure 6). The chemical functionalization is designed to form an organized self-assembled structure having a surface for active material particles, such as NMC particles for use in the positive electrode, or in the case of the negative electrode, silicon particles ("Si") or silicon oxide ("SiOx") particles. The slurry thus formed may be based on an alcohol solvent for the positive electrode and water for the negative electrode, such solvents evaporate very easily during the manufacturing process and are easy to handle. Electrostatic interactions promote the self-assembled structure in the slurry, and after the drying process, the bonding between the thus formed carbon matrix with active material particles and the surface of the current collector is promoted by a surface treatment agent (e.g., functional groups on the matrix) and strong entanglement of the active material in the carbon matrix.

[0148] As will be understood by those skilled in the art, the mechanical properties of electrodes can be easily modified by adjusting the surface functionalization versus entanglement effect, depending on the application and mass load requirements.

[0149] After coating and drying, the electrodes undergo a calorifying process to control the density and porosity of the active material. For NMC positive electrodes, densities of 3.5 g / cc or higher and porosity of 20% or higher can be achieved. Porosity can be optimized depending on the mass load and LIB cell requirements. For SiOx / Si negative electrodes, porosity is specifically controlled to accommodate the expansion of the active material during the lithiumization process.

[0150] In some typical applications, the teachings herein can result in a reduction of up to 20% $ / kWh. Using readily evaporating, gentle solvents leads to higher electrode throughput and, more importantly, a significant reduction in energy consumption due to prolonged drying. Conventional NMP recovery systems are also greatly simplified when alcohols or other solvent mixtures are used.

[0151] The teachings herein provide a 3D matrix that dramatically improves electrode conductivity by 10 to 100 times compared to electrodes using conventional binders such as PVDF, thereby enabling high-speed charging at the battery level. Using this technology, thick electrode coatings of up to 150 μm (or more) per current collector surface are possible. The solvent used in the slurry in combination with the robust 3D carbon matrix is ​​designed to achieve a thick, wet coating without cracking during the drying process. The thick cathode, together with a high-capacity anode, enables a substantial leap in energy density, reaching over 400 Wh / kg.

[0152] Fast charging is achieved by combining a high-capacity negative electrode that is lithium-ionized through an alloying process (Si / SiOx), and by reducing the overall impedance of the cell when the negative electrode and positive electrode are combined, as described herein. The teachings herein provide fast charging by having a high-conductivity electrode, specifically a high-conductivity positive electrode.

[0153] An exemplary embodiment includes a pouch-cell type lithium-ion battery energy storage device combining a Ni-rich NMC active material for the positive electrode and a SiOx and graphite blend active material for the negative electrode, both of which are fabricated using the 3D carbon matrix process described herein.

[0154] A schematic diagram of an electrode-configured pouch cell device is shown in Figure 7. As shown, a double-sided positive electrode, using polymer-binder-free positive electrode layers on opposite sides of an aluminum foil current collector, is positioned between two single-sided negative electrodes, each having a polymer-binder-free negative electrode layer disposed on a copper foil current collector. The electrodes are separated by a permeable separator material (not shown) moistened with an electrolyte (not shown). This configuration can be housed in a pouch cell of a type well known in the art.

[0155] These devices may feature a high mass load of Ni-rich NMC cathode electrode and a method for manufacturing it, i.e., a mass load of 20-30 mg / cm³. 2 Specific capacity > 210 mAh / g. SiOx / graphite negative electrode (SiOx content = approximately 20 wt%) based electrode and its material synthesis and manufacturing method: Mass load 8-14 mg / cm² 2 Reversible relative capacity ≥ 550 mAh / g. In particular, the long-life performance of the SiOx / graphite negative electrode-based Li-ion-based electrolyte of the battery: -30 to 60°C. High energy, high power density, and long cycle life Ni-rich NMC cathode / SiOx+graphite / carbon+based Li-ion battery pouch cell: capacity ≥ 5 Ah, specific energy ≥ 300 Wh / kg, energy density ≥ 800 Wh / L, and cycle life exceeding 500 cycles under 1C rate charge / discharge, and ultra-high power fast charge / discharge C rate (up to 5C rate) function. A summary of the performance parameters of this type of pouch cell is summarized in Figure 8.

[0156] Example 2 - Comparative Performance of NMC811 Lithium-ion Battery As detailed above, the teachings herein provide electrodes composed of advanced 3D high aspect ratio carbon bond structures that eliminate the need for polymer binders and provide greater power, energy density, and performance in extreme environments compared to conventional battery electrode designs (e.g., through thicker electrodes and higher mass loading of active material). High-performance Li-ion battery energy storage devices are designed and manufactured using an optimized capacity ratio design of binder-free positive / negative electrodes, pre-lithiumization of the negative electrode, and a wide operating temperature electrolyte (e.g., -30 to 60°C), as well as an optimized test formation process.

[0157] As described herein, electrodes are manufactured by completely removing high molecular weight polymers such as PVDF and toxic NMP solvents from the active material layer. This dramatically improves LiB performance while reducing manufacturing costs and capital expenditures associated with mixing, coating and drying, NMP solvent recovery, and calendering. In embodiments of the electrodes, a 3D nanoscopic carbon matrix acts as a mechanical scaffold for the electrode active material, mimicking the entanglement of polymer chains. Chemical bonds also exist between the carbon surface, the active material, and the current collector, promoting adhesion and aggregation. However, in contrast to polymers, the 3D nanoscopic carbon matrix is ​​highly conductive, thereby enabling very high power (high C rate). This scaffold structure is also more suitable for manufacturing thick electrode active materials, which is a powerful way to increase the energy density of LiB cells.

[0158] In this embodiment, a binder-free cathode featuring NMC811 as the active material was manufactured according to the teachings of this disclosure and incorporated into a lithium-ion battery (LIB). The cell featured a conventional type of graphite anode known in the art. The cell was configured as described above with reference to Figure 7, using parameters summarized in Figure 9. A conventional electrolyte consisting of 1 M LiPF6 in a mixture of ethylene carbonate and dimethyl carbonate with a vinyl carbonate additive of 1 wt% was used. For comparison, an otherwise identical cell was manufactured using a PVDF binder-based cathode. The performance of the cells was compared as described below, demonstrating the clear advantages of the binder-free cathode cell.

[0159] As shown in the results summarized in Figure 10, binder-free cells, based on a 20Ah battery cell design and graphite anode, can achieve a specific energy of 320 Wh / kg with a cycle life of over 2,000 cycles under 2C rate charge / discharge. In comparison, conventional binder-based cathode cells can only achieve a specific energy of 100-250 Wh / kg at the cell level.

[0160] The binder-free cathode cell exhibits ultra-high power fast charge-discharge C rates up to 5C, with a capacity retention rate of over 50%. Figure 10 shows a comparison of charge-discharge curves at various C rates for the binder-free cathode cell (left) and a conventional binder-based cathode cell (right). The charge-discharge curve of the binder-free cathode cell shows a combined charge-discharge capacity retention rate of over 60% at a 5C rate. Therefore, separate discharges or charges would show even higher capacity retention rates. In the provided examples, a conventional graphite anode was used, and it should be noted that initial experimental results indicate that a charge rate of 10C is achievable when a Si-dominant anode is combined with the NMC811 cathode used in these examples.

[0161] Figure 11 shows a comparison of the cycle lifetimes of the cells described above. The cells were repeatedly cycled between voltages of 2.75V and 4.2V at 25°C, and their discharge capacity was recorded. The binder-free cathode cell exhibits a lifetime of over 2,000 cycles with a discharge capacity loss of less than 20%. In contrast, the binder-based cathode cell experiences a discharge capacity loss of more than 20% after only about 1,000 cycles.

[0162] Example 3 - Comparison of Pouch Half Cells The type of binder-free positive electrode described herein can advantageously achieve high mass loading, for example, 45 mg / cm² per facet of the NMC811 active material. 2 Such mass loading is possible. This example presents experimental results demonstrating the performance of a binder-free electrode with such high mass loading compared to a control electrode characterized by a PVDF binder and NMC811 active material.

[0163] For comparison, half-cells of the type shown in Figure 12 were constructed using a single-sided positive electrode (either binder-free or binder-based control example) and lithium foil on a copper substrate as the counter electrode of the cell. The half-cells were subjected to charge rate tests under various current densities, and the results are summarized below.

[0164] Figure 13 is a plot showing the potential (relative to the Li / Li+ potential) relative capacitance of a binder-free cathode half-cell (solid trace) and a reference binder-based cathode half-cell (dashed trace) at various current densities. At all current densities (and therefore all C rates), the binder-free cathode half-cell exhibits better performance (as indicated by the relative rightward shift of the traces).

[0165] Figure 14 is a plot showing the potential (referenced to the Li / Li+ potential) versus volumetric capacitance of a binder-free cathode, with cells (solid traces) and reference binder-based cathode half-cells (dashed traces) at various current densities. At all current densities (and therefore all C rates), the binder-free cathode half-cells exhibit better performance (as indicated by the relative rightward shift of the traces).

[0166] Figure 15 shows a plot of volumetric capacity versus current density for a binder-free cathode half-cell (upper trace) and a reference binder-based cathode half-cell (lower trace). At all current densities (and therefore all C rates), the binder-free cathode half-cell exhibits better performance, with a relative performance gap that widens at higher C rates.

[0167] Figure 16 shows Nyquist plots resulting from electrochemical impedance spectroscopy of several binder-free cathode half-cells (marked with square, circular, and triangular traces) and a reference binder-based cathode half-cell. The binder-free cathode half-cells exhibit significantly better performance than the reference cell.

[0168] The figure shows that the current density ranges from 0.5 to 10 mA / cm². 2 When the (1.2C rate) is increased, both electrodes reach 45 mg / cm³. 2 Despite having the same mass load, the binder-free NMC811 electrode exhibits a significantly higher discharge capacity retention rate compared to the binder-based PVDF control NMC811 electrode. It should be noted that this C-rate test under various current densities is presented as a relative comparison between conventional binder-based PVDF cathodes and binder-free cathodes, and does not reflect the absolute C-rate performance in a complete cell configuration, such as those presented in Examples 1 and 2 above.

[0169] conclusion Any orientation terms provided herein are for illustrative purposes only and do not limit the invention. For example, the “upper” layer may also be referred to as the second layer, and the “lower” layer may also be referred to as the first layer. Other nomenclature and arrangements may be used without limiting the teachings herein.

[0170] Various other components may be included and referred to in order to provide aspects of the teachings herein. For example, additional materials, combinations of materials, and / or omissions of materials may be used to provide additional embodiments within the scope of the teachings herein.

[0171] Various modifications to the teachings herein may be implemented. Generally, modifications may be designed to meet the needs of users, designers, manufacturers, or other similar stakeholders. Modifications may be intended to meet specific performance criteria that are considered important by the parties concerned. Similarly, the acceptability of the performance should be evaluated by the appropriate users, designers, manufacturers, or other similar stakeholders.

[0172] While several chemical substances may be listed herein as providing specific functions, a given chemical substance may be useful for other purposes.

[0173] When introducing elements of the present invention or its embodiments, the articles “a,” “an,” and “the” are intended to mean that there is one or more elements. Similarly, the adjective “another,” when used to introduce an element, is intended to mean one or more elements. The terms “includes” and “have” are intended to be inclusive so that there may be additional elements other than those listed. As used herein, the term “exemplary” is not intended to imply a superlative example. Rather, “exemplary” refers to an embodiment that is one of many possible embodiments.

[0174] The entire contents of each of the above-mentioned publications and patent applications are incorporated herein by reference. In the event of any conflict between any of the cited documents and this disclosure, this disclosure shall prevail.

[0175] It should be noted that any functional language used in the claims attached herein is not intended to be construed as invoking the interpretation of § 112(f) of the U.S. Patent Act as a “means plus function” language, unless it is specifically expressed in that way by the use of the words “means for” or “process for” within each claim.

[0176] While the present invention has been described with reference to exemplary embodiments, it will be understood that various modifications can be made and equivalents can be substituted for its elements without departing from the scope of the invention. For example, in some embodiments, one of the aforementioned layers may contain multiple layers therein internally. Furthermore, many modifications will be recognized to adapt the teachings of the invention to specific fixtures, situations, or materials without departing from the essential scope of the invention. Thus, the invention is not limited to any particular embodiment disclosed as the best mode intended for carrying out the invention, and the invention is intended to include all embodiments that fall within the scope of the appended claims. [Aspect 1] It is a device, An electrode active layer, A network of high aspect ratio carbon elements, wherein voids are defined within the network, A plurality of electrode active material particles are disposed within the gaps in the network and are intertwined with the network, An apparatus comprising an electrode active layer comprising a surface treatment agent on the surface of the high aspect ratio carbon element that promotes adhesion between the high aspect ratio carbon element and the active material particles. [Aspect 2] The apparatus according to the prior art, wherein the high aspect ratio carbon element comprises an element having two main dimensions and one sub-dimension, and the ratio of the lengths of each of the main dimensions is at least 10 times that of the sub-dimension. [Aspect 3] The apparatus according to any one of the prior arts, wherein the high aspect ratio carbon element comprises an element having two main dimensions and one sub-dimension, and the ratio of the length of each of the main dimensions is at least 100 times that of the sub-dimension. [Aspect 4] The apparatus according to any one of the prior arts, wherein the high aspect ratio carbon element comprises an element having two main dimensions and one sub-dimension, and the ratio of the length of each of the main dimensions to that of the sub-dimension is at least 1,000 times. [Aspect 5] The apparatus according to any one of the prior arts, wherein the high aspect ratio carbon element comprises an element having two main dimensions and one sub-dimension, and the ratio of the length of each of the main dimensions to that of the sub-dimension is at least 100,000 times. [Aspect 6] The apparatus according to any one of the prior arts, wherein the high aspect ratio carbon elements each include an element having one main dimension and two sub-dimensions, and the ratio of the length of each main dimension to the length of each sub-dimension is at least 10 times that of each sub-dimension. [Aspect 7] The apparatus according to any one of the prior arts, wherein the high aspect ratio carbon elements each include an element having one main dimension and two sub-dimensions, and the ratio of the length of each main dimension to the length of each sub-dimension is at least 100 times that of each sub-dimension. [Aspect 8] The apparatus according to any one of the prior arts, wherein the high aspect ratio carbon elements each include an element having one main dimension and two sub-dimensions, and the ratio of the length of each main dimension to the length of each sub-dimension is at least 1,000 times that of each sub-dimension. [Aspect 9] The apparatus according to any one of the prior arts, wherein the high aspect ratio carbon elements each include an element having one main dimension and two sub-dimensions, and the ratio of the length of each main dimension to the length of each sub-dimension is at least 10,000 times that of each sub-dimension. [Aspect 10] The apparatus according to any one of the prior embodiments, wherein the high aspect ratio carbon element includes a carbon nanotube or a bundle of carbon nanotubes. [Aspect 11] The apparatus according to any one of the prior arts, wherein the high aspect ratio carbon element includes graphene flakes. [Aspect 12] The apparatus according to any one of the prior embodiments, wherein the electrode active layer contains less than 10% by weight of a polymer binder disposed in the void. [Aspect 13] The apparatus according to any one of the prior embodiments, wherein the electrode active layer contains less than 1% by weight of a polymer binder disposed in the void. [Aspect 14] The apparatus according to any one of the prior embodiments, wherein the electrode active layer contains less than 1% by weight of a polymer binder disposed in the void. [Aspect 15] The apparatus according to any one of the prior arts, wherein the electrode active layer substantially contains polymer materials other than the surface treatment agent. [Aspect 16] The apparatus according to any one of the prior arts, wherein the electrode active layer substantially does not contain a polymer material. [Aspect 17] The apparatus according to any one of the prior arts, wherein the surface treatment agent comprises a material soluble in a solvent having a boiling point of less than 202°C. [Aspect 18] The apparatus according to any one of the prior arts, wherein the surface treatment agent comprises a material soluble in a solvent having a boiling point of less than 185°C. [Aspect 19] The apparatus according to any one of the prior embodiments, wherein during the formation of the active layer, the material forming the surface treatment agent is dissolved in a solvent having a boiling point of less than 202°C. [Aspect 20] The apparatus according to any one of the prior embodiments, wherein, during the formation of the active layer, the material forming the surface treatment agent is dissolved in a solvent having a boiling point of less than 185°C. [Aspect 21] The apparatus according to any one of the prior embodiments, wherein, during the formation of the active layer, the material for forming the surface treatment agent is dissolved in a solvent containing isopropyl alcohol. [Aspect 22] The apparatus according to any one of the prior embodiments, wherein during the formation of the active layer, the material forming the surface treatment agent is dissolved in a solvent that is substantially free of n-methyl-2-pyrrolidone. [Aspect 23] The apparatus according to any one of the prior embodiments, wherein, during the formation of the active layer, the material forming the surface treatment agent is dissolved in a solvent substantially free of pyrrolidone compounds. [Aspect 24] The apparatus according to any one of the prior embodiments, wherein the network is at least 90% by weight of carbon. [Pattern 25] The apparatus according to any one of the prior embodiments, wherein the network is at least 95% by weight of carbon. [Aspect 26] The apparatus according to any one of the prior embodiments, wherein the network is at least 99% by weight of carbon. [Aspect 27] The apparatus according to any one of the prior embodiments, wherein the network is at least 99.9% by weight of carbon. [Aspect 28] The apparatus according to any one of the prior arts, wherein the network includes an electrically interconnected network of carbon elements exhibiting connectivity exceeding a penetration threshold. [Aspect 29] The apparatus according to any one of the prior embodiments, wherein the network defines one or more highly conductive paths. [Aspect 30] The apparatus according to embodiment 29, wherein the aforementioned path has a length exceeding 100 μm. [Aspect 31] The apparatus according to embodiment 29, wherein the aforementioned path has a length exceeding 1,000 μm. [Aspect 32] The apparatus according to embodiment 29, wherein the aforementioned path has a length exceeding 10,000 μm. [Aspect 33] The apparatus according to any one of the prior embodiments, wherein the network includes one or more structures formed from the carbon elements, and the structures have a total length of at least 10 times the length of the maximum dimension of the carbon elements. [Aspect 34] The apparatus according to any one of the prior embodiments, wherein the network includes one or more structures formed from the carbon elements, and the structures have a total length of at least 100 times the length of the maximum dimension of the carbon elements. [Aspect 35] The apparatus according to any one of the prior embodiments, wherein the network includes one or more structures formed from the carbon elements, and the structures have a total length of at least 1,000 times the length of the maximum dimension of the carbon elements. [Aspect 36] The apparatus according to any one of the prior embodiments, wherein the surface treatment agent includes a surfactant layer disposed on the carbon element. [Aspect 37] The apparatus according to embodiment 36, wherein the surfactant layer is bonded to the carbon element. [Aspect 38] The apparatus according to embodiment 36 or 37, wherein the surfactant layer comprises a plurality of surfactant elements, each having a hydrophobic end and a hydrophilic end, the hydrophobic end being disposed proximally to one surface of the carbon element and the hydrophilic end being disposed distally to one surface of the carbon element. [Aspect 39] The apparatus according to embodiment 38, wherein the hydrophilic end of at least a portion of the surfactant element forms a bond with the active material particles. [Aspect 40] The apparatus according to embodiment 39, wherein the bond includes an ionic bond. [Aspect 41] The apparatus according to embodiment 39, wherein the bond includes a covalent bond. [Aspect 42] The apparatus according to embodiment 39, wherein the bond includes at least one from the list consisting of π-π bonds, hydrogen bonds, and electrostatic bonds. [Aspect 43] The hydrophilic end of the surfactant element has a polar charge of the first polarity, The apparatus according to embodiment 38, wherein the active material particles have a polar charge of a second polarity opposite to that of the first polarity. [Aspect 44] The apparatus according to any one of embodiments 36 to 43, wherein the surfactant layer contains a water-soluble surfactant. [Aspect 45] The apparatus according to any one of embodiments 36 to 44, wherein the surfactant layer contains ions from hexadecyltrimethylammonium hexafluorophosphate. [Aspect 46] The apparatus according to any one of embodiments 36 to 45, wherein the surfactant layer contains an ion from at least one of the following: hexadecyltrimethylammonium tetrafluoroborate, N-(cocoalkyl)-N,N,N-trimethylammonium methyl sulfate, cocamidopropyl betaine hexadecyltrimethylammonium acetate, and hexadecyltrimethylammonium nitrate. [Aspect 47] The apparatus according to any one of embodiments 36 to 46, wherein the surfactant layer includes a layer of surfactant ions formed by dissolving an ionic compound in a solvent. [Aspect 48] The apparatus according to embodiment 47, wherein the active layer includes residual counterions for the surfactant ions formed by dissolving the ionic surfactant compound in a solvent. [Aspect 49] The apparatus according to embodiment 48, wherein the counterions are selected to be suitable for use in an electrochemical cell. [Aspect 50] The apparatus according to embodiment 49, wherein the counterion substantially does not contain a halide group. [Aspect 51] The apparatus according to any one of embodiments 48 to 50, wherein the residual counterions substantially do not contain bromine. [Aspect 52] The apparatus according to any one of Embodiments 51, wherein the ionic surfactant compound comprises at least one selected from the list consisting of hexadecyltrimethylammonium tetrafluoroborate, hexadecyltrimethylammonium tetrafluoroborate, N-(cocoalkyl)-N,N,N-trimethylammonium methyl sulfate, cocamidopropyl betaine hexadecyltrimethylammonium acetate, and hexadecyltrimethylammonium nitrate. [Aspect 53] The apparatus according to any one of the prior embodiments, wherein the carbon element is functionalized. [Aspect 54] The apparatus according to embodiment 53, wherein the carbon element is functionalized with a surfactant material. [Aspect 55] The apparatus according to embodiment 53 or 54, wherein the carbon element is functionalized with a functional group that promotes adhesion of active material particles to a network. [Aspect 56] The apparatus according to embodiment 55, wherein the functional group comprises at least one from the list consisting of a carboxyl group, a hydroxyl group, an amine group, and a silane group. [Aspect 57] The apparatus according to any one of embodiments 48 to 56, wherein the functionalized carbon element is formed from a dry aqueous dispersion containing nanoform carbon and a surfactant. [Aspect 58] The apparatus according to embodiment 57, wherein the functionalized carbon element is formed from a freeze-dried aqueous dispersion containing nanoform carbon and a surfactant. [Aspect 59] The apparatus according to embodiment 57 or 58, wherein the aqueous dispersion is substantially free of acid. [Aspect 60] The apparatus according to any one of the prior embodiments, wherein the surface treatment agent includes a thin polymer layer disposed on the carbon element that promotes adhesion of the active material to the network. [Aspect 61] The apparatus according to embodiment 60, wherein the thin polymer layer comprises a self-assembled polymer. [Aspect 62] The apparatus according to embodiment 60 or 61, wherein the thin polymer layer is bonded to the active material via hydrogen bonds. [Aspect 63] The apparatus according to any one of embodiments 60 to 62, wherein the thin polymer layer has a maximum thickness of 1 nm or less in the direction perpendicular to the outer surface of the network. [Aspect 64] The apparatus according to any one of embodiments 60 to 63, wherein the thin polymer layer has a maximum thickness of 10 nm or less in the direction perpendicular to the outer surface of the network. [Aspect 65] The apparatus according to any one of embodiments 60 to 64, wherein the thin polymer layer has a maximum thickness of 50 nm or less in the direction perpendicular to the outer surface of the network. [Aspect 66] The apparatus according to any one of embodiments 60 to 65, wherein less than 1 volume percent of the voids defined by the network is filled with the thin polymer layer. [Aspect 67] The apparatus according to any one of embodiments 60 to 66, wherein less than 0.1 volume percent of the voids defined by the network is filled with the thin polymer layer. [Pattern 68] The apparatus according to any one of embodiments 60 to 67, wherein less than 0.1 volume percent of the voids defined by the network is filled with the thin polymer layer. [Aspect 69] The apparatus according to any one of embodiments 1 to 35, wherein the surface treatment agent includes a layer of carbonaceous material formed from a pyrolysis polymer material. [Aspect 70] The apparatus according to embodiment 69, wherein the layer of carbonaceous material formed from a pyrolysis polymer material promotes adhesion of active material particles to a network. [Aspect 71] The apparatus according to any one of the prior arts, wherein the active material particles include a metal oxide. [Aspect 72] The apparatus according to any one of the prior arts, wherein the active material particles include a lithium metal oxide. [Aspect 73] The apparatus according to any one of the prior embodiments, wherein the active material is entangled in the network. [Aspect 74] The apparatus according to any one of the prior embodiments, wherein the surface treatment agent promotes adhesion between the active material layer and the current collector layer. [Aspect 75] The apparatus according to embodiment 74, wherein the surface treatment agent includes a functional group bonded to the current collector layer. [Aspect 76] The apparatus according to embodiment 75, wherein the functional group is bonded to the current collector layer having non-covalent bonds. [Aspect 77] The apparatus according to embodiment 75, wherein the functional group is bonded to the current collector layer having at least one selected from the list consisting of π-π bonds, hydrogen bonds, and ionic bonds. [Aspect 78] The apparatus according to any one of embodiments 74 to 77, wherein the current collector includes a metal foil. [Aspect 79] The apparatus according to any one of embodiments 74 to 77, wherein the active material layer has a thickness of at least 200 μm in the direction perpendicular to the current collector. [Aspect 80] The apparatus according to any one of embodiments 74 to 77, wherein the active material layer has a thickness of at least 300 μm in the direction perpendicular to the current collector. [Aspect 81] The apparatus according to any one of embodiments 74 to 77, wherein the active material layer has a thickness of at least 400 μm in the direction perpendicular to the current collector. [Aspect 82] The system further comprises an energy storage cell, and the energy storage cell is A first electrode comprising the active material layer, The second electrode and A permeable separator is disposed between the first electrode and the second electrode, The apparatus according to any one of the prior embodiments, comprising an electrolyte for wetting the first and second electrodes. [Aspect 83] It is a method, The process involves dispersing high-aspect-ratio carbon elements and surface treatment agent materials in a solvent to form an initial slurry, wherein the dispersion step results in the formation of the surface treatment agent on the high-aspect-ratio carbon elements. The active material is mixed into the first slurry to form the final slurry, The final slurry is coated onto the substrate, A method comprising drying the final slurry to form an electrode active layer. [Aspect 84] The method according to embodiment 83, wherein the high aspect ratio carbon element comprises an element having two main dimensions and one minor dimension, and the ratio of the lengths of each of the main dimensions is at least 10 times that of the minor dimension. [Aspect 85] The method according to embodiment 83 or 84, wherein the high aspect ratio carbon element comprises an element having two main dimensions and one minor dimension, and the ratio of the length of each of the main dimensions is at least 100 times that of the minor dimension. [Aspect 86] The method according to any one of embodiments 83 to 85, wherein the high aspect ratio carbon element comprises an element having two main dimensions and one minor dimension, and the ratio of the length of each of the main dimensions is at least 1,000 times that of the minor dimension. [Aspect 87] The method according to any one of embodiments 83 to 86, wherein the high aspect ratio carbon element comprises an element having two main dimensions and one minor dimension, and the ratio of the length of each of the main dimensions is at least 100,000 times that of the minor dimension. [Pattern 88] The method according to any one of embodiments 83 to 87, wherein the high aspect ratio carbon element comprises an element having one main dimension and two sub-dimensions, the ratio of the length of each main dimension to the length of each sub-dimension being at least 10 times that of each sub-dimension. [Aspect 89] The method according to any one of embodiments 83 to 88, wherein the high aspect ratio carbon element comprises an element each having one main dimension and two sub-dimensions, and the ratio of the length of each main dimension to the length of each sub-dimension is at least 100 times that of each sub-dimension. [Aspect 90] The method according to any one of embodiments 83 to 89, wherein the high aspect ratio carbon element comprises elements, each having one main dimension and two sub-dimensions, and the ratio of the length of each main dimension to the length of each sub-dimension is at least 1,000 times that of each sub-dimension. [Aspect 91] The method according to any one of embodiments 83 to 90, wherein the high aspect ratio carbon element comprises an element each having one main dimension and two sub-dimensions, and the ratio of the length of each main dimension to the length of each sub-dimension is at least 10,000 times that of each sub-dimension. [Aspect 92] The method according to any one of embodiments 83 to 91, wherein the high aspect ratio carbon element comprises a carbon nanotube or a bundle of carbon nanotubes. [Aspect 93] The method according to any one of embodiments 83 to 92, wherein the high aspect ratio carbon element includes graphene flakes. [Aspect 94] The method according to any one of embodiments 83 to 93, wherein the initial slurry has a solid content in the range of 0.1% by weight to 20.0% by weight. [Aspect 95] The method according to any one of embodiments 83 to 94, wherein the final slurry has a solid content in the range of 10.0% to 80% by weight. [Aspect 96] The method according to any one of embodiments 83 to 95, wherein the solvent has a boiling point of less than 202°C. [Aspect 97] The method according to any one of embodiments 83 to 96, wherein the solvent has a boiling point of less than 185°C. [Aspect 98] The method according to any one of embodiments 83 to 97, wherein the solvent has a boiling point of less than 125°C. [Aspect 99] The method according to any one of embodiments 83 to 98, wherein the solvent has a boiling point of 100°C or lower. [Aspect 100] The method according to any one of embodiments 83 to 99, wherein the solvent comprises at least one from the list consisting of methanol, ethanol, 2-propanol, and water. [Aspect 101] The apparatus according to any one of embodiments 83 to 100, wherein, during the formation of the active layer, the material forming the surface treatment agent is dissolved in a solvent substantially free of pyrrolidone compounds. [Aspect 102] The method according to any one of embodiments 83 to 101, wherein the solvent is substantially free of n-methyl-2-pyrrolidone. [Aspect 103] The method according to any one of embodiments 83 to 102, wherein the surface treatment agent material includes a surfactant. [Aspect 104] The method according to embodiment 103, wherein the surfactant is substantially free of halogen groups. [Aspect 105] The method according to embodiment 104, wherein the surfactant is substantially free of bromine. [Aspect 106] The method according to any one of embodiments 83 to 105, wherein forming the surface treatment agent includes forming a surfactant layer disposed on the carbon element. [Aspect 107] The method according to any one of embodiments 83 to 106, wherein the surface treatment agent is a self-organized layer. [Aspect 108] The method according to embodiment 106 or 107, wherein forming the surfactant layer involves arranging a plurality of surfactant elements on the surface of the carbon element, each of the surfactant elements having a hydrophobic end and a hydrophilic end, the hydrophobic end being located proximal to one surface of the carbon element, and the hydrophilic end being located distal to one surface of the carbon element. [Aspect 109] The method according to embodiment 108, further comprising forming a bond with the active material particles at the hydrophobic end of at least a portion of the surfactant element. [Aspect 110] The method according to embodiment 109, wherein the bond includes an ionic bond. [Aspect 111] The method according to embodiment 109, wherein the bond includes a covalent bond. [Aspect 112] The method according to embodiment 109, wherein the bond includes at least one from the list consisting of π-π bonds, hydrogen bonds, and electrostatic bonds. [Aspect 113] The hydrophilic end of the surfactant element has a polar charge of the first polarity, The method according to embodiment 108, wherein the active material particles have a polar charge of a second polarity opposite to that of the first polarity. [Aspect 114] The method according to any one of embodiments 103 to 113, wherein the surfactant material comprises at least one selected from the list consisting of hexadecyltrimethylammonium tetrafluoroborate, hexadecyltrimethylammonium tetrafluoroborate, N-(cocoalkyl)-N,N,N-trimethylammonium methyl sulfate, cocamidopropyl betaine hexadecyltrimethylammonium acetate, and hexadecyltrimethylammonium nitrate. [Aspect 115] The method according to any one of embodiments 83 to 114, wherein the initial slurry is formed by dispersing high aspect ratio carbon elements and a surface treatment agent material in a solvent, and the force applied to the aggregated carbon elements is used to slide the elements away from each other along a direction perpendicular to the short axis of the elements. [Aspect 116] The method according to any one of embodiments 83 to 114, comprising drying the final slurry at a temperature below 202°C. [Aspect 117] The method according to any one of embodiments 83 to 114, comprising drying the final slurry at a temperature below 185°C. [Aspect 118] The method according to any one of embodiments 83 to 114, comprising drying the final slurry at a temperature below 125°C. [Aspect 119] The method according to any one of embodiments 83 to 114, comprising drying the final slurry at a temperature of 100°C or lower. [Aspect 120] The method according to any one of embodiments 83 to 119, further comprising calendering the active layer to promote adhesion between the active material and the network. [Aspect 121] It is a method, The process involves dispersing high-aspect-ratio carbon elements and surface treatment agent materials in an aqueous solvent to form an initial slurry, wherein the dispersion step results in the formation of the surface treatment agent on the high-aspect-ratio carbon elements. A method comprising drying the initial slurry to remove substantially all moisture, thereby producing a dry powder of the high aspect ratio carbon having the surface treatment agent on its surface. [Aspect 122] The method according to embodiment 121, wherein drying the initial slurry includes freeze-drying the initial slurry. [Aspect 123] The method according to embodiment 121 or embodiment 122, wherein the aqueous solvent and initial slurry substantially do not contain any substance that damages the high aspect ratio carbon elements. [Aspect 124] The method according to embodiment 123, wherein the aqueous solvent and initial slurry are substantially acid-free. [Aspect 125] The method according to embodiment 124, wherein the initial slurry essentially consists of the high aspect ratio carbon element, the surface treatment agent material, and water. [Aspect 126] Dispersing the dried powder of the high aspect ratio carbon together with the surface treatment agent in a solvent, and adding it, and an active material for forming a secondary slurry, The secondary slurry is coated onto the substrate, The method according to any one of embodiments 121 to 125, further comprising drying the secondary slurry to form an electrode active layer. [Aspect 127] The method according to any one of embodiments 121 to 126, wherein the high aspect ratio carbon element comprises an element having two main dimensions and one minor dimension, and the ratio of the lengths of each of the main dimensions is at least 10 times that of the minor dimension. [Aspect 128] The method according to any one of embodiments 121 to 127, wherein the high aspect ratio carbon element comprises an element having two main dimensions and one minor dimension, and the ratio of the length of each of the main dimensions is at least 100 times that of the minor dimension. [Aspect 129] The method according to any one of embodiments 121 to 128, wherein the high aspect ratio carbon element comprises an element having two main dimensions and one minor dimension, and the ratio of the length of each of the main dimensions is at least 1,000 times that of the minor dimension. [Aspect 130] The method according to any one of embodiments 121 to 129, wherein the high aspect ratio carbon element comprises an element having two main dimensions and one minor dimension, and the ratio of the length of each of the main dimensions to that of the minor dimension is at least 100,000 times. [Aspect 131] The method according to any one of embodiments 121 to 130, wherein the high aspect ratio carbon element comprises elements, each having one main dimension and two sub-dimensions, and the ratio of the length of each main dimension to the length of each sub-dimension is at least 10 times that of each sub-dimension. [Aspect 132] The method according to any one of embodiments 121 to 131, wherein the high aspect ratio carbon element comprises an element each having one main dimension and two sub-dimensions, and the ratio of the length of each main dimension to the length of each sub-dimension is at least 100 times that of each sub-dimension. [Aspect 133] The method according to any one of embodiments 121 to 132, wherein the high aspect ratio carbon element comprises elements, each having one main dimension and two sub-dimensions, and the ratio of the length of each main dimension to the length of each sub-dimension is at least 1,000 times that of each sub-dimension. [Aspect 134] The method according to any one of embodiments 121 to 133, wherein the high aspect ratio carbon element includes a carbon nanotube or a bundle of carbon nanotubes. [Aspect 135] The method according to any one of embodiments 121 to 134, wherein the high aspect ratio carbon element includes graphene flakes. [Aspect 136] The method according to any one of embodiments 121 to 135, wherein the solvent has a boiling point of less than 202°C. [Aspect 137] The method according to any one of embodiments 121 to 135, wherein the solvent has a boiling point of less than 185°C. [Aspect 138] The method according to any one of embodiments 121 to 135, wherein the solvent has a boiling point of less than 125°C. [Aspect 139] The method according to any one of embodiments 121 to 135, wherein the solvent has a boiling point of 100°C or lower. [Aspect 140] The method according to embodiments 121 to 139, wherein the secondary solvent comprises at least one from the list consisting of methanol, ethanol, 2-propanol, and water. [Aspect 141] The method according to any one of embodiments 121 to 140, wherein the secondary solvent is substantially free of pyrrolidone compounds. [Aspect 142] The method according to any one of embodiments 121 to 141, wherein the secondary solvent is substantially free of n-methyl-2-pyrrolidone. [Aspect 143] The method according to any one of embodiments 121 to 142, wherein the surface treatment agent material includes a surfactant. [Aspect 144] The method according to embodiment 143, wherein the surfactant is substantially free of halogen groups. [Aspect 145] The method according to embodiment 144, wherein the surfactant is substantially free of bromine. [Aspect 146] The method according to any one of embodiments 121 to 145, wherein forming the surface treatment agent includes forming a surfactant layer disposed on the carbon element. [Aspect 147] The method according to embodiment 146, wherein the surfactant layer is a self-organizing layer. [Aspect 148] The method according to any one of embodiments 126 to 147, comprising drying the secondary slurry at a temperature below 202°C. [Aspect 149] The method according to any one of embodiments 126 to 147, comprising drying the secondary slurry at a temperature below 185°C. [Aspect 150] The method according to any one of embodiments 126 to 147, comprising drying the secondary slurry at a temperature below 125°C. [Aspect 151] The method according to any one of embodiments 126 to 147, comprising drying the secondary slurry at a temperature of 100°C or lower. [Aspect 152] The method according to any one of embodiments 121 to 151, further comprising calorending the active layer to promote adhesion.

Claims

1. It is a device, An electrode active layer, A network of high aspect ratio carbon elements, wherein voids are defined within the network, A plurality of electrode active material particles are disposed within the gaps in the network and are intertwined with the network, The electrode active layer comprises the high aspect ratio carbon element and a surface treatment agent on the surface of the high aspect ratio carbon element that promotes adhesion between the high aspect ratio carbon element and the plurality of electrode active material particles, A high aspect ratio is defined as a ratio of the principal dimension to the minor dimension of a carbon element being at least 5. The electrode active layer contains less than 10% by weight of a polymer binder disposed within the void, The aforementioned high aspect ratio carbon element includes carbon nanotubes or bundles of carbon nanotubes. The network comprises an electrically interconnected network of carbon elements that are at least 99% by weight of carbon and exhibit connectivity exceeding a penetration threshold, and defines one or more highly conductive paths. The surface treatment agent comprises a surfactant layer disposed on the high aspect ratio carbon element, the surfactant layer comprises a plurality of surfactant elements bonded to the high aspect ratio carbon element, each having a hydrophobic end and a hydrophilic end, the hydrophobic end being disposed proximally to the surface of the high aspect ratio carbon element, and the hydrophilic end being disposed distally to the surface of the high aspect ratio carbon element. The surface treatment agent further comprises a thin polymer layer disposed on the high aspect ratio carbon element, which promotes the adhesion of the electrode active material particles to the network. The plurality of electrode active material particles include lithium metal oxide, The electrode active layer does not contain polymer binders other than the surface treatment agent. An apparatus wherein the surfactant layer is located on the high aspect ratio carbon element, and the thin polymer layer is located on the surfactant layer.

2. The apparatus according to claim 1, wherein the high aspect ratio carbon element comprises an element having two main dimensions and one sub-dimension, and the ratio of the lengths of each of the main dimensions is at least 10 times that of the sub-dimension.

3. The apparatus according to claim 1, wherein the high aspect ratio carbon elements each include an element having one main dimension and two sub-dimensions, and the ratio of the length of the main dimension to the length of each sub-dimension is at least 100 times.

4. The apparatus according to claim 1, wherein the high aspect ratio carbon elements each include an element having one main dimension and two sub-dimensions, and the ratio of the length of the main dimension to the length of each sub-dimension is at least 1,000 times.

5. The apparatus according to claim 1, wherein the surface treatment agent comprises a material soluble in a solvent having a boiling point of less than 185°C.

6. The apparatus according to claim 5, wherein the material forming the surface treatment agent is soluble in a solvent that does not contain pyrrolidone compounds.

7. The apparatus according to claim 1, wherein the hydrophilic end of at least a portion of the surfactant element forms a bond with the plurality of electrode active material particles.

8. The apparatus according to claim 7, wherein the bond includes a non-covalent bond.

9. The hydrophilic end of the surfactant element has a polar charge of the first polarity, The apparatus according to claim 1, wherein the plurality of electrode active material particles have a polar charge of a second polarity opposite to that of the first polarity.

10. The apparatus according to claim 1, wherein the surfactant layer contains a water-soluble surfactant.

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