EP4690318A2

EP4690318A2 - Energy storage devices

Info

Publication number: EP4690318A2
Application number: EP24781793.5A
Authority: EP
Inventors: Wanjun Ben Cao; Ji Chen; Nicolo Brambilla
Original assignee: Nanoramic Inc
Current assignee: Nanoramic Inc
Priority date: 2023-03-27
Filing date: 2024-03-27
Publication date: 2026-02-11
Also published as: CN120883378A; WO2024206397A3; WO2024206397A2; KR20250169546A

Abstract

The abstract is as provided on page 30 of the description.

Description

ENERGY STORAGE DEVICES

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Application No. 63/454,818, filed on March 27, 2023, which is incorporated herein by reference in its entirety.

BACKGROUND

[0002] This disclosure relates to electrode for use in energy storage devices such as capacitors, ultracapacitors, batteries, and the like. In particular, this disclosure relates to the preparation of slurries for manufacturing electrodes for energy storage devices such as capacitors, ultracapacitors, batteries, and the like. This disclosure also relates to energy storage devices that do not use polyvinylidene fluoride as a binder and that do not use N- methylpyrollidone as a solvent.

[0003] Making slurry is a crucial stage in the manufacturing of batteries that can significantly impact the future steps. Lithium battery anodes and cathodes are made with high viscous slurries that contain a large percentage of solid particles in a variety of chemistries, sizes, and shapes. The production of batteries faces a significant hurdle when it comes to facilitating the mixing of these slurries. The mixer selection and mixing order are one of many factors that should be taken into account when creating the slurry.

[0004] It is therefore desirable to determine the relationship between the slurry's rheological behavior and the structural, mechanical, and electrochemical performance of lithium ferro-phosphate (LFP) and lithium nickel manganese cobalt oxides (NMC) electrodes in order to improve battery properties, quality and manufacturing processes.

SUMMARY

[0005] Disclosed herein is a method comprising mixing a first polymer binder with carbonaceous conductive materials to produce a first blend; adding to the first blend a second polymer binder in a first solvent to produce a second blend; mixing the second blend; adding to the second blend a third polymer binder in a second solvent to produce a third blend; mixing the third blend; adding to the third blend an active material to form an active material composition; and mixing the active material composition.

[0006] Disclosed herein is a Li-ion battery cell comprising a cathode that comprises a cathode current collector and a cathode active layer; where the cathode active layer comprises cathode active materials that include one or more of LFP, LiCoCL, LiNiCE, LiNi MnCoCU LiNiC , LiMi C , LiFePC , and LiNi_xMn_yCoi-x-yO2, NCMA, or a combination thereof, where x has a value 0.7 to 0.85 and where y is greater than 0.1; and wherein the cathode active layer contacts the cathode current collector; an anode that comprises an anode current collector and an anode active layer; where the anode active layer comprises an anode active material that includes graphite mixed with Li_xSi_yO_z, where x is 1 to 15, y is 1 to 4 and z is 1 to 9; the anode active layer contacts the anode current collector; and where both the anode active layer and the cathode active layer each comprise high aspect ratio carbon elements that entrap the anode active material and the cathode active material respectively in voids in the high aspect ratio carbon elements.

BRIEF DESCRIPTION OF THE FIGURES

[0007] FIG. 1 is a diagram of an electrode (an anode or a cathode) according to various embodiments;

[0008] FIG. 2 is a general depiction of the mixing process to form the active material composition;

[0009] FIGs. 3 - 5 depict various methods of mixing the ingredients to form the active material composition;

[0010] FIG. 6 is a graph depiction the viscosity of the composition versus shear rate for compositions produced by the processes described herein;

[0011] FIG. 7 is a graph depiction the viscosity of the composition versus shear rate for compositions produced by the processes described herein; and

[0012] FIGs. 8 - 9 are graphs showing the electrochemical performance of LFP half cells using NX LFP cathode paired with an Li metal counter electrode.

DETAILED DESCRIPTION

[0013] Longer range, faster charging, safer, more durable, and affordable storage devices such as ultracapacitors, batteries, capacitors, and the like, are more frequently being used to promote the shift to an EV (electric vehicle) society powered by renewable energy. Currently, EV battery performance is limited by the conventional PVDF-NMP processing based cathode electrodes, which has lower electrical and ionic conductivity. The high molecular weight PVDF binders are the main cause of non-uniform porosity distribution, material agglomeration in active layer, and poor electrical conductivity. This problem is more prominent in high mass loading thick cathodes (>5 mAh/cm2) required in high energy density Li-ion battery designs. On the anode side, graphite (Gr) or Gr/SiO (5-10%SiO) anode electrodes are widely used in the EV battery industry.

[0014] However, because of the Gr’s low potential versus Li/Li+ (0.05-0.1 V vs. Li/Li+) during battery charging process, fast-charging (FC) performance is very difficult to achieve for long-term battery FC cycling, especially when high loading Gr anode matches the high loading PVDF/NMP based cathode electrodes (>5 mAh/cm²). For example, these conventional NMP/PVDF cathode combined with Gr anode electrodes are not compatible with fast charging as they have high impedance and do not allow moderate to high C-rates in both charge and discharge.

[0015] Disclosed herein are energy storage devices where polymeric binders such as PVDF (polyvinylidene fluoride) are not used in the preparation of the active layer. Solvents such as N-methylpyrollidone (NMP) are also avoided. This dramatically improves Li-Ion ultracapacitor and battery cell performance while decreasing the cost of manufacturing and the capital expenditures related to mixing, coating and drying, NMP solvent recovery, and calendering.

[0016] In the NX electrodes, a 3D nanocarbon matrix works as a mechanical scaffold for the electrode active material and mimics the polymer chain entanglement. The NX electrodes are made via a NX process and includes a novel high shear mixing process that is developed for blending and mixing electrode slurry homogenously in multiple stages or in a single stage (e.g., in one pot). The composition made by this high shear process is devoid of polyvinylidene fluoride (PVDF) and N- methylpyrollidone (NMP) and is referred to a NX high shear mixing process.

[0017] The engineered surface chemistry of the nanocarbon materials, active materials (hybrid lithium nickel cobalt manganese aluminum oxide (NCMA) and lithium manganese iron phosphate (LMFP) facilitate safer performance), and the current collector promotes excellent mechanical stability for the resulting electrode architecture. As opposed to PVDF polymer, the 3D nanocarbon matrix is highly electrically conductive, allowing for significantly thicker cathode active layer while improving the electrical conductivity of the electrode. By using eco-friendly solvents that are easily evaporated, the electrode throughput is higher, and, more importantly, the energy consumption from electrode drying process is reduced by 30% due to reduction of temperature from 150 °C-180 °C required by the NMP to 60-70 °C. When paired with water-based processing NX Si- dominant anode, drastic increase the energy density and FC capability of EV battery cells can be achieved.

[0018] Disclosed herein are active materials for the cathode and anode that are devoid of polyvinylidene fluoride and that do not use NMP as a solvent for processing.

[0019] Disclosed herein too is a method that includes high shear of a slurry for producing improved electrode active layers that may be used in the electrodes of batteries. The high shear process produces high electrochemical performance electrodes by combining a number of different mixing tools and methods with a multistage mixing sequence.

[0020] Portable electronics, electric vehicles, and hybrid electric vehicles all employ rechargeable lithium-ion batteries (LIBs) to supply power and energy. Because of LIB’s high energy and power densities, established dependability, lengthy cycle life, and flexible design, the market for LIBs has experienced rapid growth over the past ten years.

[0021] Scalable LIB manufacturing involves mixing high solid-content slurries. As a result, the electrode structure can be affected by the mixer type and mixing process parameters, particularly the order in which the materials are introduced (the "mixing sequence") and the intensity and duration of each step, which are crucial in determining the quality and electrochemical performance of the battery. To create well-mixed slurries for diverse electrode materials, various mixing sequences have been researched. Kim et al. discovered that dry mixing the LiCoCL (LCO) and conductive agent, then adding the solution of polyvinylidene fluoride (PVDF) in N-methyl-2-pyrrolidone (NMP) to form a slurry, can yield the greatest capacity and stability of charge and discharge cycle. According to Bauer et al., the configuration of the PVDF and carbon black (CB) dispersion can affect the stability and rheological characteristics of slurries utilizing NMP as the solvent. The addition of CB to PVDF can aid in the formation of a stable coagulated gel system, giving it resistance to the LiNiMnCoO2 (NMC) particle’s quick sedimentation. Later, Bauer et al. discovered that a drying mixing process of NMC/CB powder mixes before adding PVDF solution can cause CB shells on NMC surfaces, lowering the viscosity and stability of the slurry. If PVDF was then coated on the CB shells after drying, the conductive contact with NMC would be inhibited. This issue was resolved by adding additional CB or graphite during the homogenization process.

[0022] For use in laboratories, the effectiveness of a variety of mixing equipment including ball mills, magnetic stirrers, and supersonic waves have been investigated. In the industrial setting, large-scale mixers like planetary mixers, high-speed mixers, universal mixers, and static mixers are frequently employed. A well-dispersed slurry mixture can only be attained by choosing the right mixer for the highly viscous anode and cathode slurries as well as by following specific protocols for introducing solid particles and binders into solvents.

[0023] For example, a ball mill mixer seems to be an appropriate tool for mixing electrode slurries, but the lengthy mixing time detracts from its effectiveness. Therefore, it is preferable to look for alternative mixers that can speed up the mixing process and decrease mixing time. The effectiveness of a mixer can be evaluated empirically using a grindometer and rheological measurements.

[0024] The first step in the assembly of a battery (cell) is the deposition of a slurry containing the active material, conducting material and optional polymeric binder in a solvent on to a copper film or an aluminium film (the current collector). This is followed by drying, calendaring and sizing of the electrodes. To deliver desirable electrochemical performance, the multistep manufacturing process of energy storage device electrodes need to be closely controlled.

[0025] Slurries are a very complex suspension system containing a large percentage of solid particles of different chemicals, sizes and shapes in a highly viscous media. A thorough mixing of the slurry is desirable for homogeneity. Rheological properties of slurries affect important attributes: slurry stability, ease of mixing and coating performance, which impact finished electrodes. Composition and applied processing conditions can have an impact on the rheology of the resulting slurry. Density and viscosity quantify flow properties and characterize the degree of structure within the sample and the extent to which solid- or liquid-like behavior dominates. In electrode manufacturing process, viscosity of in-process constituents plays a valuable role in battery fabrication processes such as coating.

[0026] Viscosity of the polymeric binder solution affects coating performance. It influences the ease with which the powders are dispersed within it, the power used for mixing and the speed of application of uniform coating. The Porous Electrode Theory (PET) suggests the relevance of positive electrode density on overall performance of lithium-ion battery cells, validated by experiments. Cells with high positive electrode density show a slightly higher discharge capacity at low current rates but at high current rates, cells with a low positive electrode density show a better performance.

[0027] In this disclosure, a novel high shear mixing process was developed for blending and mixing electrode slurry homogenously in multiple stages or in a single stage (e.g., in one pot). The composition made by this high shear process is devoid of polyvinylidene fluoride (PVDF) and N-methylpyrollidone (NMP) and is referred to a NX high shear mixing process. A particle size approach employing a Hegman gauge was used to initially assess the performance of the mixing process. Following that, rheological analysis using shear viscosity and dynamic tests were conducted to determine how well anode and cathode materials were mixed. Electrical performance tests were performed on the batteries that were created from the slurries produced by various mixers and mixing schemes. [0028] This one pot solution greatly reduces the cost to manufacture by limiting the infrastructure used in the coating process. Typically, processes used for manufacturing active layers that contain carbonaceous materials use significant amounts of NMP to produce a slurry that is coated on a current collector. Using solvents such as NMP to facilitate the coating involves significant venting, handling, safety, and recycling protocols, all of which are eliminated from the NX high shear mixing process. The NX high shear mixing process uses water or alcohols that are miscible with water at all temperatures.

[0029] The water-based lithium ferro-phosphate (LFP) process combined with the NX high shear mixing process for manufacturing battery electrodes can be used on standard, high speed, high volume manufacturing equipment with no additional infrastructure updates. The electrodes (manufactured from this process) are improved over current and future battery designs as well. This NX manufacturing process for battery electrodes is relevant across Li- ion and solid-state battery markets, especially for the electric vehicle market.

[0030] FIG. 1 is a diagram of an electrode (an anode or a cathode) according to various embodiments. In the example shown, electrode 100 is provided. According to various embodiments, electrode 100 comprises current collector 102 and active layer 106. Electrode 100 may optionally include an adhesion layer 104. As an example, adhesion layer 104 comprises a material that promotes adhesion between current collector 102 and active layer 106.

[0031] In an embodiment, with regard to the FIG. 1, the electrode (the anode or the cathode) comprises a current collector 102 that is an electrically conductive layer. For example, current collector 102 may be a metal, metal alloy, etc. In another embodiment, the current collector 102 is a metal foil. In some embodiments, current collector 102 is an aluminum foil or aluminum alloy foil. In some embodiments, current collector 102 is a copper foil or copper alloy foil. The current collector 102 has a thickness of less than 30 pm, preferably less than 10 pm, preferably less than 8 pm, and more preferably less than 5 pm.

[0032] In an embodiment, the current collector 102 has a thickness of 3 to 15 pm. In some preferred embodiments, current collector 102 has a thickness of between about 6 pm and about 8 pm. In some embodiments, current collector 102 is an aluminum foil or an aluminum alloy foil, and current collector 102 has a thickness of about 10 to about 15 pm.

[0033] The electrodes of lithium batteries comprise complex combinations of materials and mixtures. The key component in the cathode is an active material such as lithium ferro-phosphate (LFP), LiCoO2, LiNiO2, or LiNi_xMn_yCo_zO2. Other components in the formulation often include a binder, like polyvinylidene fluoride (PVDF), a solvent, such N-methyl-2-pyrrolidone (NMP), and a carbon additive, like carbon black (CB), to increase the conductivity of the battery.

[0034] The active constituents in the anode combination include silicon and graphite, while other components such as the binder, solvent, and conductive agents are often the same as those used in the cathode. For a typical formulation, the solid compositions of the anode and cathode active materials range from 50% to 99.9%. The binder's content ranges from 0.1% to 15%. Higher binder concentrations may improve adhesion, but they may increase resistivity. The compositions for the cathode and the anode active layers are discussed in detail below.

Active Material for Cathode

[0035] The active layer slurry for the cathode (which is disposed on the current collector) includes an active material, a carbonaceous conductor, a solvent and an optional binder. The active material, the carbonaceous conductor, the solvent and the optional binder are mixed together to form the slurry. The mixing will be described in detail later. The slurry after the appropriate mixing is disposed on the current collector, followed by solvent evaporation to form the active layer.

[0036] In an embodiment, the active material used in the cathode may include lithium cobalt oxide (LCO, sometimes called “lithium cobaltate" or “lithium cobaltite,”. One variant of possible LCO formulations is LiCoO2); lithium nickel manganese cobalt oxide (NMC, with a variant formula of LiNi_xMn_yCo(i-x-y) O2); lithium nickel cobalt manganese aluminum oxide (NCMA), with a variant formula of LiNi Mn_yCozAl(i-x-_y-z) O2); lithium manganese oxide (LMO with variant formulas of LiMn2O4, Li2MnOa or the like, or a combination thereof); lithium titanate oxide (LTO, with one variant formula being Li^isOn); lithium iron phosphate (LFP, with one variant formula being LiFePO4); lithium manganese iron phosphate (LMFP); lithium nickel cobalt aluminum oxide (LiNixCoyAlzCL) as well as other similar other materials. Other variants of the foregoing may be included. In some embodiments where NMC is used as an active material, nickel rich NMC may be used.

[0037] For formulations such as LiNi Co_yAl_zO2 and LiNi_xMn_yCo_zO2, x > 0.8, z < 0.05 and x + y + z = l. In some embodiments, where the variant of NMC may be LiNi_xMn_yCo(i- - _y), x is equal to or greater than about 0.7, 0.75, 0.80, 0,85 or more. In an embodiment, y may be equal to or greater than 0.1, 0.15, 0.2 or 0.25. In some embodiments, NMC811 may be used where x is about 0.8 and y is about 0.1. [0038] In some embodiments, the active material can include lithium cobalt oxide (LiCoCL). The LiCoCL material can be further doped with certain metal species to increase its high-voltage stability. The batteries containing LiCoCL (with or without doping) as the cathode active material can be charged to a high-voltage (> 4.7 V vs. Li/Li⁺) to increase cell energy density.

[0039] In some embodiments, the active material can include lithium manganese iron phosphate (LMFP). The chemical formula of LMFP can be LiMn_xFei-_xPO4, where x is in the range of 0.1 to 0.9, preferably 0.3 to 0.7. Increase of Mn content in the LMFP material is beneficial for increasing energy density. In an embodiment, the polymeric binder for LMFP and LCO can be water based polymers for high voltage applications for aqueous (where the solvent is water or a water-containing solvent) processing.

[0040] For ethanol solvent, the binder can be polyacrylic acid combined with some polyamide and polyvinyl pyrollidone (PVP).

[0041] For a solvent that comprises water, the polymeric binder may be a copolymer of polyacrylonitrile and a polyether.

[0042] In some embodiments, the active material includes other forms of lithium nickel manganese cobalt oxide (LiNi_xMn_yCoi-_x-yO2). Variants of this formula that may be used in the active material layer include NMC111 (detailed below), NMC532 (LiNio.5Mno.3Coo.2O2), NMC622 (LiNio.6Mno.2Coo.2O2), or a combination thereof.

[0043] In an embodiment, the active material used in the cathode may include a combination of nickel, manganese, and cobalt. Lithium-Nickel-Manganese-Cobalt-Oxide (LiNiMnCoO2), abbreviated as NMC delivers strong overall performance, excellent specific energy, and the lowest self-heating rate of all mainstream cathode powders. The NMC powder may comprise nickel in an amount of 20 to 40 atomic percent, manganese in an amount of 20 to 40 atomic percent and cobalt in an amount of 20 to 40 atomic percent, based on a total weight of the NMC blend. While the term “NMC powder” can refer to a variety of blends, it is desirable to use a blend that comprises 33 atomic percent nickel, 33 atomic percent manganese and 33 atomic percent cobalt. This blend, sometimes referred to as 1-1-1 (NMC 111) is useful for applications that use frequent cycling (automotive, energy storage) due to the reduced material cost resulting from lower cobalt content.

[0044] The active material is contained in the active layer in an amount of 67 to 99 wt%, preferably 90 to 99 wt%, based on the total weight of the active layer (when it is devoid of solvent). Active Material for the Anode

[0045] The anode active material can comprise silicon (Si), germanium (Ge), tin (Sn), lead (Pb), antimony (Sb), bismuth (Bi), zinc (Zn), aluminum (Al), titanium (Ti), nickel (Ni) , cobalt (Co), cadmium (Cd); alloys or two or more thereof or alloys thereof with other elements; oxides, carbides, nitrides, sulfides, phosphides, selenides, and tellurides of those metals and their mixtures or lithium-containing composites; salts and hydroxides of Sn; lithium titanate, lithium manganate, lithium aluminate, lithium-containing titanium oxide, lithium transition metal oxide; pre-lithiated versions thereof; particles of Li, Li alloy, or surface stabilized Li having at least 60% by weight of lithium, or combinations thereof. The active material can comprise graphite in lieu of or in addition to the anode active material. As one example, the anode active material can comprise a silicon oxide and/or carbon silicon oxide. Such anode active material comprising a silicon oxide or carbon silicon oxide can further comprise graphite.

[0046] In an embodiment, the active material used in the anode is a lithium-based active material. An example of a lithium-based active material is Li_xSi_yO_z, where x is 1 to 15, preferably 2 to 7, y is 0 to 4, preferably 1 or 2, and z is 0 to 9, preferably 1 to 5. SiO is synthesized by mixing silicon and silica in a 1 : 1 molar ratio and then subliming the mixture to collect the amorphous SiO (a-SiO) material. Since the silicon atoms in a-SiO are randomly distributed, their valence numbers can be 0, 1+, 2+, 3+, and 4+ upon the bonding condition with different numbers of oxygen atoms. Some silicon atoms agglomerate and form tiny silicon crystals surrounded by other amorphous substances, with Si-0 bonds that have different valence numbers of silicon. In LIBs, these tiny silicon crystals in a-SiO react with Li⁺ ions and form LiisSi4, serving as the active material to store energy. Owing to the nano scale of tiny silicon crystal, no pulverization occurs after lithiation; therefore, good reversibility can be obtained.

[0047] Examples of lithium based active materials include LiisSi4, Li2SiO3, Li2Si20s, LieSi2O7, Li4SiO4, Li2O, or a combination thereof.

[0048] In an embodiment, the lithium based active materials may be blended with a carbonaceous material to form a Li-SiOx-C active material. In other words, the active material may comprise lithium, silicate and carbon. The carbon in the form of carbon black, carbon nanotubes or graphite may be blended and pulverized with the Li_xSi_yO_z (where x, y and z values are detailed above) to form aggregates and agglomerates of Li-SiOx-C active material. [0049] In manufacturing the Li-SiOx-C active material, elemental silicon (Si) may first be reacted and blended with a silicate material (SiOx). The combination of silicon with the silica is subjected to reaction and grinding processes in order to create a powder. To this powder is added carbon in a carbon coating process and lithium in a lithium doping process. After the process of adding carbon and lithium, the formed Li-SiOx-C material will be in a classification process to form the final usable anode active material called Li-SiO with carbon coatings. The relative density of the formed material can be ~2.1 g/cm³ at 25 °C.

[0050] In an embodiment, an energy storage device may have an initial charge specific capacity of 1500 to 1600 mAh/g, preferably 1400 to 1500 mAh/g with an initial coulombic efficiency of 90 to 94%; preferably 1350 to 1400 mAh/g with an initial coulombic efficiency of 87 to 89%.

[0051] The lithium may be added in elemental form or in the form of a compound. Some of these lithium compounds are listed herein. The D50 particle size for the Li-SiOx-C particles prepared in this manner is 6 to 9 micrometers. The BET surface area of the formed Li-SiOx-C material can be 3 to 4 m²/g with a carbon content of 3 to 4 wt%, based on a total weight of the Li-SiOx-C active material. The initial charge specific capacity to 5 mV vs. Li/Li⁺ of the cell (also referred to as an energy storage device) with the Li-SiOx-C anode can be 1500 to 1600 mAh/g, and the initial discharge specific capacity to 2.0 V vs. Li/Li+ of the cell with the Li-SiOx-C anode material can be 1400 to 1500 mAh/g with an initial coulombic efficiency of 90 to 94%; and the initial discharge specific capacity to 1.0 V vs. Li/Li+ of the cell with the Li-SiOx-C material can be 1350 to 1400 mAh/g with an initial coulombic efficiency of 87 to 89%.

[0052] The manufacturing of Li-SiOx and Li-SiOx-C active materials and the corresponding electrodes are detailed in U.S. Patent No. 9,825,290B2 and U.S. Patent Application No. 2019/0237761A1, the entire contents of which are incorporated by reference.

[0053] In an embodiment, the anode active material may include graphite flakes. The graphite flakes are preferably high aspect ratio graphite flakes where at least one dimension is larger than any other dimension. The graphite flakes may be naturally occurring or commercially synthesized flakes. The graphite flakes are particulate like and may be ellipsoidal in shape. The aspect ratio of these graphite flakes may range from 2:1 to 20:1, preferably 5:1 to 12:1. In an embodiment, the graphite flakes may be intercalated with metal ions. In another embodiment, the graphite flakes may be exfoliated flakes.

[0054] The graphite flakes may be present in the solid anode active layer (the solid active layer comprises the electrically conductive material, the binder material, the electrode active material without the solvent) in an amount of 5 to 90 wt%, preferably 8 to 65 wt%, based on the entire weight of the solid anode active layer (when it is devoid of solvent).

[0055] The anode active materials may be present in the anode active layer in an amount of 40 to 95 wt%, based on a total weight of the anode active layer (when it is devoid of solvent).

Carbonaceous conductive material

[0056] The carbonaceous conductive material is used separately in both the anode and cathode active layers and comprises electrically conductive elements. The electrically conductive elements (also referred to as electrically conductive material) can comprise carbon. For example, the conductive elements can be high aspect ratio carbon elements. The term “high aspect ratio carbon elements” refers to carbonaceous elements having a size in one or more dimensions (the “major dimension(s)”) significantly larger than the size of the element in a transverse dimension (the “minor dimension”). The high aspect ratio carbon elements can comprise a substantially cylindrical network of carbon atoms. The electrically conductive material can comprise carbon nanotubes or a plurality of bundles of carbon nanotubes.

[0057] In an embodiment, the electrically conducting material used in the anode and/or cathode may include graphite flakes. This is described later.

[0058] The electrically conductive material can form an electrically conducting percolating network that can transmit an electrical current between any two separated points located on a surface of the solid active layer (without the solvent in it). In other words, an electrical current can be transmitted from one surface or end to an opposing surface or end of the active layer by virtue of physical contacts or electron hopping between the electrically conductive elements in the electrode active layer. The percolating network can comprise voids between the high aspect ratio carbon elements that can contain or house the electrode active materials. The high aspect ratio electrically conductive material can be substantially oriented in the electrode active layer 106 in a direction substantially parallel to the current collector to facilitate conducting electrical current from one end of the electrode to the other while still maintaining some lesser orientation through the thickness of the active layer.

[0059] The electrically conductive material can be present in the mixture in amounts of 0.1 to 1.3, or 0.15 to 1.2, or 0.3 to 1 weight percent, based on the total weight of the mixture (the mixture comprises the electrically conductive material, the electrode active material, the binder material and a solvent). The electrically conductive material can be present in the active layer in amounts of 0.2 to 3.5, or 0.3 to 3, or 0.5 to 2 weight percent based on total weight of solids in the active layer (total weight solids comprises electrically conductive material, the binder material, the electrode active material without the solvent). The electrode active material as used herein may refer to the anode active material or the cathode active material.

[0060] The high aspect ratio carbon elements can be single wall carbon nanotubes (SWCNTs), double wall carbon nanotubes (DWNTs), multiwall carbon nanotubes (MWNTs), thin walled nanotubes (TWNTs), carbon black, carbon nano-fiber, carbon nanotube fiber, porous carbons or a mixture of different types.

[0061] The single wall carbon nanotubes can have an outer diameter of 0.5 to 5.0 nanometers, preferably 1.0 to 3.5 nanometers. The single wall carbon nanotubes can have an aspect ratio (length to diameter ratio) greater than about 2.0, preferably greater than 5.0, preferably greater than 10.0, greater than 50 and more preferably greater than 100. In an exemplary embodiment, the single wall carbon nanotubes can have an average aspect ratio of 5 to 200.

[0062] The single wall carbon nanotubes can have a length greater than 6 nanometers, preferably greater than 10 nanometers, preferably greater than 15 nanometers, preferably greater than 30 nanometers, preferably greater than 50 nanometers, more preferably greater than 100 nanometers, preferably greater than 1 micrometer, preferably greater than 5 micrometers, preferably greater than 10 micrometers, and more preferably greater than 15 micrometers up to at least 200 micrometers. In an exemplary embodiment, the single wall carbon nanotubes can have an average length of 10 nanometers to 20 micrometers, preferably 20 nanometers to 15 micrometers.

[0063] The single wall carbon nanotubes can present in the mixture of electrically conductive material, binder material, electrode active material and solvent in an amount of 0.1 to 0.3 weight percent, preferably 0.15 to 0.25 weight percent based on the total weight of the mixture.

[0064] The single wall carbon nanotubes are present in the electrode active layer (electrically conductive material, binder material, and electrode active material without the solvent) in an amount of 0.2 to 0.6 wt%, preferably 0.3 to 0.5 wt%, based on the entire weight of the electrode active layer.

[0065] In another embodiment, the SWNTs may comprise a mixture of metallic nanotubes and semi-conducting nanotubes. Metallic nanotubes are those that display electrical characteristics similar to metals, while the semi-conducting nanotubes are those, which are electrically semi-conducting. In general, the manner in which the graphene sheet is rolled up produces nanotubes of various helical structures. Zigzag and armchair nanotubes constitute two possible confirmations. In order to minimize the quantity of SWNTs utilized in the composition, it is generally desirable to have the composition comprise as large a fraction of metallic SWNTs. It is generally desirable for the SWNTs used in the composition to comprise metallic nanotubes in an amount of greater than or equal to about 1 wt %, preferably greater than or equal to about 20 wt %, more preferably greater than or equal to about 30 wt %, even more preferably greater than or equal to about 50 wt %, and most preferably greater than or equal to about 99.9 wt % of the total weight of the SWNTs. In certain situations, it is generally desirable for the SWNTs used in the composition to comprise semi-conducting nanotubes in an amount of greater than or equal to about 1 wt %, preferably greater than or equal to about 20 wt %, more preferably greater than or equal to about 30 wt %, even more preferably greater than or equal to about 50 wt %, and most preferably greater than or equal to about 99.9 wt % of the total weight of the SWNTs.

[0066] In a embodiment, the single wall carbon nanotubes in their metallic form are present in the electrode active layer (electrically conductive material, binder material, and electrode active material without the solvent) in an amount of 0.2 to 0.6 wt%, preferably 0.3 to 0.5 wt%, based on the entire weight of the electrode active layer. The electrode active layer referred to herein can be either the cathode active layer or the anode active layer.

[0067] The number of carbon walls in the multi-wall carbon nanotubes can be 2 or more, 5 or more, 10 or more, 50 or more. The multi-wall carbon nanotubes can comprise an average of between 3 layers to 15 layers, 4 to 12 layer, 5 to 10 layers, 6 to 8 layers.

[0068] The D50 particle size distribution of the carbon black or porous carbon can be in the range of 0.1 pm to 100 pm. The total Brunauer-Emmett-Teller (BET) surface area of the carbon black or porous carbon can be at least 50 m²/g, preferably at least 500 m²/g. The carbon black or porous carbon can present in the electrode active layer (electrically conductive material, binder material, and electrode active material without the solvent) in an amount of 0.2 to 1.0 wt%, preferably 0.3 to 0.5 wt%, based on the entire weight of the electrode active layer.

[0069] The active layer 106 (see FIG. 1) can comprise multi-wall carbon nanotubes and single-wall carbon nanotubes. The multi-wall carbon nanotubes swell more than singlewall carbon nanotubes when wetted with an electrolyte in an energy storage device in which electrode 100 is located. For example, the multi-wall carbon nanotubes can swell at least 15%, or at least 25% or at least 50% more than single-wall carbon nanotubes when wetted with an electrolyte in an energy storage device in which electrode 100 is located. For example, a length of the multi-wall carbon nanotubes can expand at least 15%, or at least 25% or at least 50% more than a length of the single-wall carbon nanotubes when wetted with the electrolyte. As another example, the multi-wall carbon nanotubes swell up to 50% when wetted (e.g., a length of the multi-wall carbon nanotubes is 50% larger after wetting with an electrolyte, and/or a diameter of the multi-wall carbon nanotubes is 50% larger after wetting, etc.).

[0070] The multi-wall carbon nanotubes can have an outer diameter of 2.0 to 50 nanometers, 5.0 to 40 nanometers, or 6 to 10 nanometers. The multi-wall carbon nanotubes can have a length greater than 10 nanometers, greater than 15 nanometers, greater than 30 nanometers, greater than 50 nanometers, greater than 100 nanometers, greater than 500 nanometers, greater than 1 micrometer, greater than 5 micrometers, greater than 10 micrometers, or greater than 15 micrometers. At the same time the multi- wall carbo nanotubes can have an average length up to 25 micrometers or up to 20 micrometers. In exemplary embodiments, the multi-wall carbon nanotubes have an average length of 10 nanometers to 20 micrometers, or 20 nanometers to 15 micrometers. The multi- wall carbon nanotubes can have an aspect ratio (length to diameter ratio) greater than 5.0, greater than 10.0, greater than 50, greater than 100, or greater than 500.

[0071] The electrode comprises multi-wall carbon nanotubes can be relatively longer in comparison to multi-wall carbon nanotubes comprised in related art electrodes. The use of relatively longer multi-wall carbon nanotubes in electrodes is found to have beneficial mechanical and/or electrical properties. For example, multi- wall carbon nanotubes provide relatively good power at low densities. As another example, shorter multiwall carbon nanotubes generally do not swell (e.g., expand) as much as longer multiwall carbon nanotubes. As such use of shorter multi-wall carbon nanotubes loses (or reduces) some of the beneficial properties associated with swelling of the carbon nanotubes. As an extreme example, carbon black does not exhibit swelling because carbon black is merely particles of carbon without entanglement such as the entanglement exhibited by a set of multi-wall carbon nanotubes. An indication that a length of a certain amount of multi- wall carbon nanotubes have a length exceeding a threshold length and thus have sufficient swelling properties is an observation during a calendering process - a relatively larger amount of pressure or effort to calendar the active layer in connection with applying to the foil is indicative that the collective swelling (e.g., an average swelling) of the multi-wall carbon nanotubes in the active layer will satisfy a certain performance threshold. However, multiwall carbon nanotubes are generally difficult to process.

[0072] The processing of the multi-wall carbon nanotubes in connection with preparing/forming the active layer and/or electrode is gentler than processes for related art electrodes. As such, the processes according to various embodiments maintain longer multiwall carbon nanotubes (e.g., less multi-wall carbon nanotubes are crushed, fragmented, broken, etc.). In some embodiments, the active layer of the electrode comprises a set of multiwall carbon nanotubes having an average length that is more an average length of the multiwall carbon nanotubes in related art electrodes. According to various embodiments, a distribution of lengths of the set of multi-wall carbon nanotubes is skewed towards a nominal length a multi-wall carbon nanotube. As an example, the nominal length of a multi-wall carbon nanotube is about 16 microns. For example, the multi- wall carbon nanotubes are processed and/or applied in a manner that reduces or minimizes fracturing or breaking of multi- wall carbon nanotubes. The lengths of the multi- wall carbon nanotubes in the network of high aspect ratio carbon elements are generally the nominal length of the multi-wall carbon nanotubes, or a length of such the multi-wall carbon nanotubes tend to be more heavily skewed to the nominal length. In some embodiments, at least 75% of the multi-wall carbon nanotubes within the network of high aspect ratio carbon elements are within 10% of the nominal length (e.g., between 13.4 microns to about 15 microns). In some embodiments, at least 75% of the multi- wall carbon nanotubes within the network of high aspect ratio carbon elements have a length of at least 12 microns. In some embodiments, at least 75% of the multiwall carbon nanotubes within the network of high aspect ratio carbon elements have a length of at least 13 microns. In some embodiments, at least 50% of the multi-wall carbon nanotubes within the network of high aspect ratio carbon elements are within 10% of the nominal length (e.g., between 13.4 microns to about 15 microns). In some embodiments, at least 50% of the multi-wall carbon nanotubes within the network of high aspect ratio carbon elements have a length of at least 12 microns. In some embodiments, at least 50% of the multiwall carbon nanotubes within the network of high aspect ratio carbon elements have a length of at least 8 microns. In some embodiments, at least 50% of the multi-wall carbon nanotubes within the network of high aspect ratio carbon elements have a length of at least 13 microns.

[0073] According to various embodiments, a distribution of lengths of the set of multi-wall carbon nanotubes is skewed towards a nominal length a multi-wall carbon nanotube. For example, the multi-wall carbon nanotubes are processed and/or applied in a manner that reduces or minimizes fracturing or breaking of multi- wall carbon nanotubes. The lengths of the multi-wall carbon nanotubes in the network of high aspect ratio carbon elements are generally the nominal length of the multi-wall carbon nanotubes, or a length of such the multi-wall carbon nanotubes tend to be more heavily skewed to the nominal length.

[0074] In some embodiments, at least 75% of the multiwall carbon nanotubes within the network of high aspect ratio carbon elements are within 10% of the nominal length (e.g., between 13.4 micrometers to about 15 micrometers). In some embodiments, at least 75% of the multi-wall carbon nanotubes within the network of high aspect ratio carbon elements have a length of at least 12 micrometers. In some embodiments, at least 75% of the multi-wall carbon nanotubes within the network of high aspect ratio carbon elements have a length of at least 13 micrometers. In some embodiments, at least 50% of the multi-wall carbon nanotubes within the network of high aspect ratio carbon elements are within 10% of the nominal length (e.g., between 13.4 micrometers to about 15 micrometers). In some embodiments, at least 50% of the multi-wall carbon nanotubes within the network of high aspect ratio carbon elements have a length of at least 12 micrometers. In some embodiments, at least 50% of the multiwall carbon nanotubes within the network of high aspect ratio carbon elements have a length of at least 13 micrometers.

[0075] The multi-wall carbon nanotubes can be present in the mixture (the mixture comprises the electrically conductive material, the electrode active material, the binder material and a solvent or a combination of solvents) in an amount of 0.3 to 1.0 weight percent, preferably 0.4 to 0.9 weight percent based on the total weight of the mixture. The multi-wall carbon nanotubes are present in the solid anode active layer (the solid active layer comprises the electrically conductive material, the binder material, the electrode active material without the solvent) in an amount of 0.8 to 2.6 wt%, preferably 1.0 to 1.8 wt%, based on the entire weight of the solid anode active layer (when it is devoid of solvent).

[0076] In an example where both multi- wall and single wall carbon nanotubes are used, the ratio of the weight of the multi-wall carbon nanotubes to the weight of the single wall carbon nanotubes in the mixture or in the solid active material layer can be at least 2:1.

[0077] In one example, three-dimensional network of high aspect ratio carbon elements 108 comprises carbon nanotubes, and the carbon nanotubes are only multi-wall carbon nanotubes and/or fragments of such carbon nanotubes.

[0078] In another example, the multiwall carbon nanotubes are present in the mixture or in the solid anode active material layer in an amount that is at least twice the amount of the single wall carbon nanotubes, based on the weight of the conductive materials. [0079] In an embodiment, the carbon nanotubes may comprise randomly dispersed carbon nanotubes in which are dispersed clumps of brush like oriented nanotubes. The brush-lie oriented nanotubes are randomly dispersed in the randomly dispersed carbon nanotubes, but within each brush-like clump the nanotubes are aligned. The aligned nanotubes in the brush-like clump may have a length that is greater than the thickness of the active layer (i.e., the cathode active layer or the anode active layer).

[0080] The network of three-dimensional network of high aspect ratio carbon elements 108 can comprise at least 99% carbon by weight.

[0081] In addition to the high aspect ratio carbon elements (the carbon nanotubes), the electrically conductive materials may optionally comprise graphite flakes, carbon black, or a combination thereof.

[0082] Carbon black, or porous carbon can also be used in addition to the carbon nanotubes. These carbon materials are typically a high surface area carbon that has a surface area of greater than 50 square meters per gram (m²/gm), preferably greater than 200 m²/gm, and more preferably greater than 500 m²/gm. An example of a high surface area carbon black is KELTJEN Black. The carbon materials are optional and may be present in the solid anode active layer (the solid active layer comprises the electrically conductive material, the binder material, the electrode active material without the solvent) in an amount of 0.5 to 2.0 wt%, preferably 0.8 to 1.6 wt%, based on the entire weight of the solid anode active material. While the presence of high aspect ratio carbon nanotubes benefits the electrical conductivity and cell rate performance, the ID carbon materials (carbon black or porous carbons) are generally cheaper and can enable optimal slurry rheology properties at a high slurry solid content.

[0083] The three-dimensional network of high aspect ratio carbon elements 108 can comprise an electrically interconnected network of carbon elements exhibiting connectivity above a percolation threshold and wherein the network defines one or more highly electrically conductive pathways having a length greater than 100 pm. The percolation threshold is one where the conducting elements contact one another to provide an electrically conducting network measured across any two points on any surface of the network.

The Polymer Additive/Binder

[0084] In an embodiment, the electrode active materials (the anode active material or the cathode active material) and the carbonaceous conductive material are held together by a binder. The binder may include organic polymeric materials such as, for example, cellulose, polyacetals, polycarbonates, polyalkyds, polystyrenes, polyolefins, polyesters, polyamides, polyaramides, polyamideimides, polyarylates, polyurethanes, epoxies, phenolics, silicones, poly arylsulfones, polyethersulfones, polyphenylene sulfides, polysulfones, polyimides, poly acrylates, poly etherimides, polytetrafluoroethylenes, poly etherketones, polyether ether ketones, polyether ketone ketones, polybenzoxazoles, polyoxadiazoles, polybenzothiazinophenothiazines , polybenzothiazoles , polypyrazinoquinoxalines , polymethylacrylates, poly iso-butyl methacrylates, polypyromellitimides, polyguinoxalines, polybenzimidazoles, polyoxindoles, polyoxoisoindolines, polydioxoisoindolines, poly triazines, polypyridazines, polypiperazines, polypyridines, polypiperidines, polytriazoles, polypyrazoles, polycarboranes, polyoxabicyclononanes, poly dibenzofurans, polyphthalides, polyacetals, poly anhydrides, polyvinyl ethers, polyvinyl thioethers, poly vinyl butyral, polyvinyl alcohols, polyvinyl ketones, polyvinyl nitriles, polyvinyl esters, polysulfonates, polysulfides, polythioesters, polyacrylonitrile, styrene-butadiene rubber, polysulfones, polysulfonamides, polyureas, polyphosphazenes, polysilazanes, polypropylenes, polyethylenes, polyethylene terephthalates, polysiloxanes, or the like, or a combination thereof.

[0085] The binder is present in the active layer in an amount of 0.1 to 15 wt%, preferably 1 to 10 wt%, and more preferably 1.5 to 5 wt%, based on the total weight of the active layer (when it is devoid of solvent). In an embodiment, the binder is present in the form of an emulsion prior to being mixed into the active material that is disposed on the current collector. The binder is preferably water soluble or is made compatible with a water soluble polymer so that it can be dissolved in water. Water soluble solvents may also be used for dispersing the binder, the high aspect ratio carbon elements 108.

Solvent

[0086] In the preparation of the slurry, a solvent is used to facilitate blending of the active material (either the anode active material or the cathode active material), the carbonaceous conductive material, the binder, and any other additives if desired. The solvent is preferably one that can dissolve the binder. Suitable solvents are water, alcohol, or a combination thereof. Examples of alcohol are ethanol, methanol, propanol, butyl alcohol, ethylene glycol, propylene glycol, or a combination thereof. In addition to water and alcohol, other solvents may be added to facilitate solubilization and/or dispersion of the polymer. Other solvents include polar solvents, non-polar solvents, and the like. The addition of other solvents should preferably not change the solubility of the polymer in the water or alcohol. Liquid aprotic polar solvents such as propylene carbonate, ethylene carbonate, butyrolactone, acetonitrile, benzonitrile, nitromethane, nitrobenzene, sulfolane, dimethylformamide, N- methylpyrrolidone, or the like, or combinations thereof may be added to water or alcohol for dissolution of the polymer. Polar protic solvents such acetonitrile, nitromethane, acetone, dimethyl sulfoxide, dimethylformamide, or the like, or a combination thereof may be used. Other non-polar solvents such a benzene, toluene, methylene chloride, carbon tetrachloride, hexane, diethyl ether, tetrahydrofuran, or the like, or a combination thereof may also be used. Co- solvents comprising at least one aprotic polar solvent and at least one non-polar solvent may also be utilized to modify the solubilization power of the solvent.

[0087] In an embodiment, the solvent only contains water and is ethanol-free. In another embodiment, the solvent only contains ethanol and is water-free. In another embodiment, the solvent can be a mixture of water and ethanol. When water and alcohol are used as the solvents for the active layer the ratio of water to alcohol is 80:20 to 95:5, preferably 88:12 to 92:8. In an exemplary embodiment, the ratio of water to alcohol is 90:10. The choice of solvent system is dependent on the compatibility of active materials, availability of binders and slurry rheology properties.

[0088] The solvent is present in an amount of 30 to 60 wt%, preferably 40 to 55 wt%, based on the total weight of the first slurry. The solvent is preferably removed from the active layer after it is disposed on the current collector. The solid active layer preferably is free of solvent (water and alcohol).

Processing to form the active material

[0089] FIGs. 3-5 shows a general mixing strategy of the cathode slurry w/ NX HS processing. Using the unique optimization of the NX process, the NX mother slurry can be fully dispersed and homogenously mixed for downstream processing with additional polymer solution, carbon additives, and active materials. In this method detailed in the FIG. 3, the carbonaceous material and the polymeric binder are first mixed in step 1002 in a solvent or solvent mixture to form the mother slurry. In an embodiment, the solvent only contains water and is ethanol-free. In another embodiment, the solvent only contains ethanol and is water- free. In another embodiment, the solvent can be a mixture of water and ethanol. When water and alcohol are used as the solvents for the active layer the ratio of water to alcohol is 80:20 to 95:5, preferably 88:12 to 92:8. In an exemplary embodiment, the ratio of water to alcohol is 90:10. The process to form the active material comprises first blending a portion of the ingredients in a NX high-shear (HS) process to form a uniform blend. The machines used for such purposes can be a ball milling machine, magnetic stirrers, supersonic waves or a planetary dispersion (PD) mixer. In an exemplary embodiment, a commercial PD mixer from MTI Corporation can be used. During mixing of the ingredients in the PD mixer, the stirring blade can be set at a stirring speed of 20 - 70 rpm, preferably at 30 - 60 rpm. The dispersion blade can be set at a dispersion speed of 600 - 2000 rpm, preferably at 1000 - 1800 rpm. This first blend may be a dry blend or may be conducted in a portion of the solvent that is used to facilitate the blending. If a dispersant is used to facilitate the blending of the conductive materials into the active material, then it is also added at this stage. The mixing in step 1002 is conducted for 5 to 120 minutes, preferably 10 to 60 minutes.

[0090] The mixing for steps 1004 to 1012 are all conducted using commercially available mixing machines, including ball milling machine, magnetic stirrers, supersonic waves or a PD mixer, blade and dispersion mixing. In an exemplary embodiment, a commercial PD mixer from MTI Corporation can be used. During mixing of the ingredients in the PD mixer, the stirring blade can be set at a stirring speed of 20 - 70 rpm, preferably at 30 - 60 rpm. The dispersion blade can be set at a dispersion speed of 600 - 2000 rpm, preferably at 1000 - 1800 rpm.

[0091] The mother slurry produced in step 1002 comprises the carbonaceous conductive material, the binder and any desirable optional dispersants, under a dry blending process or with a solvent. The mother slurry is first mixed till the desired distribution of the carbonaceous conductive material in the binder (and the optional dispersant is achieved). Following this additional polymeric binder in a solvent is added to the mother slurry in several steps - notably steps 1004 - 1012. In step 1004 and step 1006 additional binder may be added in one or more increments to the vessel. It is to be noted that the entire sequence of steps from 1002 to 1010 are conducted in a single vessel. More vessels that one may be used if desired. However, it is preferable to conduct the entire mixing in a single vessel.

[0092] With each increment of binder addition in steps 1004 and 1006 further mixing is conducted using blade and dispersion mixing. In these steps, the binder is added in the form of a solution. In other words, a solvent may be added to the binder to solubilize the binder and the solution of the binder in the solvent is then added in increments in these steps. The mixing in steps 1004 and 1006 may be conducted for 5 to 120 minutes, preferably 10 to 60 minutes.

[0093] The active material such as NCM/NCMA/LFP, LFMP, or the like, is then added to the same mixing vessel in step 1008. It may be added continuously or stepwise. The mixing to add the active material is conducted for 5 to 120 minutes, preferably 10 to 60 minutes. Step 1010 is optional and features the addition of additional solvent to the blend in the vessel. The mixing in step 1010 may be conducted for 5 to 120 minutes, preferably 10 to 60 minutes to form the final cathode slurry (see step 1012). The cathode slurry obtained in step 1012 is disposed on a film of metal (the current collector) and dried to form the active material layer. The active material layer thus disposed on the current collector forms the electrode, which may be used in an energy storage device. While this process is detailed for manufacturing a cathode active layer, it can also be used to manufacture the anode active material and the anode active layer.

[0094] FIG. 4 depicts another process involving steps 2002 through 2012. The manufacturing process of the FIG.4 is similar to that of the FIG. 3 except that the penultimate step 1010 of the FIG. 3 becomes the second step 2004 of the FIG. 4. FIG. 4 depicts another manner of mixing the ingredients to form the cathode active layer. In this method, the water and alcohol is added to the mother slurry (see step 2004) (of the FIG. 3) directly after it is formed (see step 2002). The mother slurry together with the water and alcohol is subjected to additional blade and dispersion mixing (see step 2004). Additional binder together with solvent is then added to the mixture of the mother slurry and water and alcohol in several steps with some mixing in between each step (see steps 2006 and 2008). After satisfactory mixing has occurred, the active materials are added to the mixture of solvent, binder, carbonaceous conductive material to form the cathode (or anode) active material (see step 2010). The cathode (or anode) active material is then disposed on a current collector and dried (by removing the solvent, water and alcohol) to form the active layer (see step 2012).

[0095] FIG. 5 depicts another process involving steps 3002 through 3012. The manufacturing process of the FIG. 5 is similar to that of the FIG. 4 except that the step 2008 of FIG. 4 becomes the penultimate step 3010 of the FIG. 5. Additionally, step 2006 of FIG. 4 becomes an optional step in step 3006 of FIG. 5 depending on slurry rheology properties.

[0096] The mixing steps disclosed herein may be exemplified by the following nonlimiting examples.

Example 1

[0097] These examples shown in the Tables 1 - 3 exemplify compositions that were manufactured using the processes described herein. Tables 1 - 3 detail the compositions with the respective ingredients.

[0098] As noted above, there are typically four main components in both the cathode and anode slurries. These are a binder, a solvent, a carbonaceous conductive material and an active material. The solid powders that make up the active and conductive materials range in size from nano to micro sizes. These solid powders are combined with a binder in an organic (ethanol) or aqueous solvent (H2O). For example, N-methyl-2-pyrrolidone (NMP) and poly vinylidene fluoride (PVDF) are typically used as the industrial standard, respectively.

[0099] Complex inorganic compounds with Li ions are the most prevalent active components for the cathode. These include LiCoCL, LiNiCL, LiM CL, LiFePCL, and LiNixMnyCoi-x-yCL. Batteries made with these active materials have demonstrated high energy capacity, extended life, and good heat resistance. They have been extensively utilized as cathode materials in consumer electronics as well as in electrical vehicles.

For example, the active material used in our investigation was LFP. These particles range in size from 0.5 to 12 pm on average. The conductive agents were two carbon powders namely 0.5-2 wt% carbon black with an average size of about 1 to 10 pm and 0.5 to 2 wt% CNTs with an average size of 20 to 100 nm. The slurry had a solid content of 40 to 70 wt%, based on the total weight of the slurry. After coating and drying, the dry weight of LFP electrode had a final composition of more than 80-99 wt%. Table 1 contains a list of the various compositions of cathode materials.

Table 1

Design of Experiments for LFP / LFMP cathode Development

[0100] The viscosity for a blend of the mother slurry that is mixed with one or more binders / dispersant and LFP is shown on a graph in the FIG. 6. In the FIG. 6, the viscosity of each of the blends decreases as the shear rate increases. FIG. 7 depicts the viscosity of several blends that contain the mother slurry that is mixed with binders/dispersant and NCM, where each of the blends is mixed for increasing periods of time. From the FIG. 7, it may be seen that there is a decrease in the blend viscosity with increasing mixing time periods.

[0101] Preliminary results below show an LFP cathode (16-35 mg/cm³) can be coated without any cracking issues, good flexibility, and a pressed density of 2.4-2.7 g/cm³ can be achieved (FIG. 9). High areal capacity loading cathodes containing LFP of greater than or equal to 5.5 mAh/cm² can be produced. The electrochemical performance of LFP half cells using NX LFP cathode paired with an Li metal counter electrode is shown in FIG. 8 and FIG. 9. When the LFP cathodes are paired with NX Si/C anodes, LFP full Cell energy density of greater than 240 Wh/kg, preferably greater than or equal to 560 Wh/L were produced. The LFP-SiGr battery cell energy density can be ranged from 200-250 Wh/kg and 490-570 Wh/L range for EV large-format battery cells depending on the battery cell design and electrode loadings. This represents a greater than 30% improvement in performance compared with LFP industry cell standard. The cell cycle life is greater than or equal to 1000 cycles (70% nominal capacity). Si-dominant anode may be pre-li thiated to achieve longer cycle life for NX LFP-Si cells to control the anode potential vs. Li/Li+ to be in the range between 0.05V to 0.8 V during the full battery cell cycle life. The anode electrodes can be not pre-lithiated too. Or the anode electrodes are pre-lithiated in 10-20% lithiation degree based on the total anode areal capacity to control the anode potential vs. Li/Li+ to be in the range between 0.05V to 0.8 V during the full battery cell cycle life. An anode potential 0.1V to 0.75V vs. Li/Li+ during the cycle life of the cell is preferred. The electrolyte contains salt type and solvent type additives including LiFSI and FEC. The separator is coated with PVDF material with 1- 2um thickness range. The anode active layer areal capacity/cathode active layer areal capacity ratio is from 1.05-1.25. The electrolyte used in the battery cells are disclosed in patent application WO2021226483 Al to Hyde, the entire contents of which are hereby incorporated in their entirety by reference.

[0102] Examples of solvents that may be used as electrolytes in the battery cell are shown below.

[0103] As detailed above, a novel NX HS mixing process was developed for blending and mixing electrode slurry homogenously in multiple stages or in one pot. A particle size approach employing a Hegman gauge was used to initially assess the performance of the mixing process. Following that, rheological analysis using shear viscosity and dynamic tests was done to determine how well anode and cathode materials mixed. Electrical performance tests were performed on the batteries that were created from the slurries produced by various mixers and mixing schemes. [0104] This one pot solution greatly reduces the cost to manufacture by limiting the infrastructure required for the coating process. This water-based LFP process with NX HS mixing process for manufacturing battery electrodes can be used on standard, high speed, high volume manufacturing equipment with no additional infrastructure updates. The electrodes will be improvements in most current and future battery designs as well. This NX manufacturing process for battery electrodes is relevant across Li-ion and solid-state battery markets, especially for the electric vehicle market.

[0105] The resulting energy storage device is a high mass loading PVDF-free NCMA/LMFP containing cathode electrodes with thin Si-dominant anodes. The energy storage device enables a substantial jump in energy density for an EV battery cell (projected as >350-400Wh/kg, >900 Wh/L), while enabling fast charging (10 mins at 80% state of charge (SOC)).

[0106] A comparison between contemporary battery performance and the proposed cell is shown in the Table below.

Table

Claims

CLAIMS What is claimed is:

1. A method comprising: mixing a first polymer binder with carbonaceous conductive materials to produce a first blend; adding to the first blend a second polymer binder in a first solvent to produce a second blend; mixing the second blend; adding to the second blend a third polymer binder in a second solvent to produce a third blend; mixing the third blend; adding to the third blend an active material to form an active material composition; and mixing the active material composition.

2. The method of Claim 1, wherein the first polymer binder is different from the second polymer binder.

3. The method of Claim 1, wherein the second polymer binder is different from the third polymer binder.

4. The method of Claim 1, wherein the first polymer binder is the same as the second polymer binder.

5. The method of Claim 1, wherein the second polymer binder is the same as the third polymer binder.

6. The method of Claim 1, wherein the first polymer binder, the second polymer binder and the third polymer binder are all soluble in water, in alcohol, or in a combination thereof.

7. The method of Claim 6, wherein the alcohol is ethanol.

8. The method of Claim 1, wherein the first solvent is different from the second solvent.

9. The method of Claim 1, wherein the first solvent is the same as the second solvent.

10. The method of Claim 1, wherein the mixing to produce the first blend, the second blend or the third blend is conducted in the same mixing vessel.

11. The method of Claim 1, wherein the mixer that conducts the mixing to produce the first blend, the second blend or the third blend is a planetary blender.

12. The method of Claim 1, further comprising adding additional first solvent or second solvent to the first blend, the second blend or the third blend.

13. The method of Claim 1, where the active material may be an anode active material, a cathode active material, or a combination thereof.

14. The method of Claim 13, where the anode active material comprises silicon, graphite, or a combination thereof.

15. The method of Claim 14, where the anode active material comprises Li_xSi_yO_z, where x is 1 to 15, y is 1 to 4 and z is 1 to 9.

16. The method of Claim 13, where the cathode active material comprises LFP, LiCoCL, LiNiCL, LiNiMnCoCL, LiNiCL, Lil h CU, LiFePCU, and LiNi_xMn_yCoi-_x.yO2, where x has a value 0.7 to 0.85 and where y is greater than 0.1.

17. A Li-ion battery cell comprising: a cathode that comprises a cathode current collector and a cathode active layer; where the cathode active layer comprises cathode active materials that include one or more of LFP, LiCoCL, LiNiCL, LiNiMnCoCL, LiNiCL, LiNL CL, LiFePCU, and LiNi_xMn_yCoi-_x.yO2, NCMA, or a combination thereof, where x has a value 0.7 to 0.85 and where y is greater than 0.1; and wherein the cathode active layer contacts the cathode current collector; an anode that comprises an anode current collector and an anode active layer; where the anode active layer comprises an anode active material that includes graphite mixed with Li_xSiyOz, where x is 1 to 15, y is 1 to 4 and z is 1 to 9; the anode active layer contacts the anode current collector; where both the anode active layer and the cathode active layer each comprise high aspect ratio carbon elements that entrap the anode active material and the cathode active material respectively in voids in the high aspect ratio carbon elements.

18. The battery-cell of Claim 17, where the anode active layer is not pre-lithiated.

19. The battery-cell of Claim 17, where the anode active layer is pre-lithiated in an amount of 10 to 20% based on the total anode areal capacity.

20. The battery-cell of Claim 17, where an anode potential vs. Li/Li+ is controlled between 0.05-0.8 V vs. Li/Li+ during battery cell cycling.

21. The battery cell of Claim 17, wherein a high mass loading PVDF-free NX NCMA/LMFP cathode electrodes with NX thin Si-dominant anodes has a substantial jump in energy density for EV battery cell (projected as >350-400 Wh/kg, >900 Wh/L), while enabling fast charging (10 mins 80%SOC).

22. The battery-cell of Claim 17, where an electrolyte used in the battery-cell comprises a salt and solvent; where the salts and solvents are shown in a Table below

23. The battery-cell of Claim 17, wherein a separator used in the battery-cell is coated with poly vinylidene (PVDF) material having a thickness of 1 to 2 micrometers; and wherein the PVDF is laminated to the separator at 1 to 10 MPa, 80 to 100°C for a time period of 10 to 60 seconds.