Solvent-free production of electrodes, fluoride-free electrodes and energy storage devices produced thereby

Abstract

The invention provides a solvent-free method for preparing an electrode paste. The electrode paste comprises a carbonaceous conductive material, a plasticizer, an active material and a polymeric binder to form the electrode paste. The electrode paste has a fluorine content of less than about 900 parts per million.

Description

[0001] Cross Reference to Related Applications

[0002] This application claims the benefit of U.S. Application No. 63 / 532,481, filed August 14, 2023, which is incorporated by reference herein in its entirety. TECHNICAL FIELD

[0003] The present disclosure relates to the solvent-free preparation of electrodes and the resulting fluorine-free electrodes. The invention also relates to energy storage devices, particularly supercapacitors and lithium ion batteries, that use the fluorine-free electrodes. In particular, the present disclosure relates to slurries for making fluorine-free electrodes for energy storage devices. BACKGROUND

[0004] Lithium batteries are used in many products, including medical devices, electric cars, airplanes, and consumer products such as laptops, cell phones, and cameras. Lithium ion batteries have taken over the secondary battery market due to their high energy density, high operating voltage, and low self-discharge, and are finding new uses in products and emerging industries.

[0005] Typically, lithium ion batteries (“LIB” or “LiB”) contain an anode, a cathode, and an electrolyte material, such as an organic solvent containing a lithium salt. More specifically, the anode and cathode (collectively, “electrodes”) are formed by mixing an anode active material or a cathode active material with a binder and a solvent to form a paste or slurry, which is then coated on a current collector, such as aluminum or copper, and dried to form a thin film on the current collector. The anode and cathode are then layered or coiled before being encased in a pressurized housing containing the electrolyte material, which all together form a lithium ion battery.

[0006] The production of lithium ion batteries typically relies on toxic and expensive components, such as solvents and fluorinated polymers, to provide the stability and performance required for the finished energy storage device. Recovering toxic and / or expensive solvents during manufacturing adds cost and process complexity. Furthermore, fluorine-containing binders, such as polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE), are perfluoroalkyl and polyfluoroalkyl substances known as PFAs, which introduce toxic and potentially bioaccumulative breakdown products.

[0007] There remains a need for the manufacture of energy storage device electrodes that are more environmentally friendly, less expensive, and free of expensive PFAs. SUMMARY

[0008] Disclosed herein is a solvent-free method for preparing an electrode slurry, the method comprising mixing a carbonaceous conductive material, a plasticizer, an active material, and a polymeric binder to form an electrode slurry, wherein the electrode slurry has a fluorine content of less than 900 parts per million.

[0009] Also disclosed herein is a battery cell comprising a cathode electrode and an anode electrode, the cathode comprising a cathode current collector and a cathode active layer, wherein the cathode active layer comprises a cathode active material comprising LFP, LiCo02, LiNi02, LiNiMnCo02, LiNi02, LiMn204, LiFeP04, and LiNi x Mn y Co 1-x-y O2, one or more of NCMA, or a combination thereof, wherein the value of x is 0.7 to 0.85 and wherein y is greater than 0.1; and wherein the cathode active layer is in contact with the cathode current collector; the anode comprising an anode current collector and an anode active layer; wherein the anode active layer comprises an anode active material comprising a mixture of graphite, silicon, tin, germanium, and x Si y O z graphite, wherein x is 1 to 15, y is 1 to 4, and z is 1 to 9; the anode active layer is in contact with the anode current collector; wherein both the anode active layer and the cathode active layer each comprise a high aspect ratio carbon element; wherein the cathode, the anode, or both are prepared by a solventless method, and the fluorine content of the battery electrode is less than 900 parts per million.

[0010] Also disclosed herein is an energy storage device comprising: a housing; a separator, a cathode, and an anode disposed in the housing; wherein the anode and the cathode are disposed on opposite sides of the separator; and wherein the cathode and the anode each comprise a current collector having an active layer disposed thereon; wherein the active layer comprises a carbonaceous conductive material, a plasticizer, an active material, and a binder; wherein the cathode, the anode, or both are prepared by a solventless method; and wherein the fluorine content of the active layer is less than 900 parts per million.

[0011] The foregoing features and elements can be combined in various combinations without exclusivity, unless expressly indicated otherwise. These features and elements as well as the operation thereof are further described in the following specification and claims with reference to the following attached drawings. It will be appreciated that the following description and drawings are intended to be illustrative and explanatory in nature and non-limiting. BRIEF DESCRIPTION OF DRAWINGS

[0012] The following is a brief description of the drawings, wherein like elements are numbered alike and which presents examples of the exemplary embodiments disclosed herein, but is not intended to be limiting thereof.

[0013] Figure 1 is a flow chart showing an example of a solventless method that can be used to prepare an electrode slurry for electrode fabrication; and

[0014] Figure 2 is a graph of an example of an electrode (anode or cathode) as disclosed herein. DETAILED DESCRIPTION

[0015] A more complete understanding of the components, processes and apparatuses disclosed herein can be obtained by reference to the following detailed description in conjunction with the accompanying drawings. These drawings are not intended to limit the scope of the exemplary embodiments, and are merely intended for illustrative purposes for clarity. Although specific terms are used in the following description for the sake of clarity, these terms are intended to refer only to the particular structure of the embodiments selected for illustration in the drawings and are not intended to limit or restrict the scope of the disclosure in any way. In the drawings and the following description, like numbers refer to like components, unless otherwise indicated.

[0016] Disclosed herein is a solvent-free, PFA-free, and fluorine-free electrode slurry composition comprising an electrically conductive material, an active material, a polymeric additive, and a plasticizer. As disclosed herein, the electrode slurry composition can be used to make an electrode (anode or cathode).

[0017] “and / or” includes any and all combinations of one or more of the associated listed items.

[0018] As used herein, “fluorine-free” means a fluorine content of less than about 900 parts per million (ppm).

[0019] As used herein, “homogeneously dispersed” means a uniform or substantially uniform distribution of components in a mixture.

[0020] As used herein, “non-toxic” means a material that is substantially non-hemolytic, non-toxic, and non-cytotoxic.

[0021] As used herein, “volatile substance” means a substance having a boiling point of less than 100 °C.

[0022] All ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other (e.g., ranges of “up to 25 wt%, or, more specifically, 5 wt% to 20 wt%” is inclusive of the endpoints and all intermediate values of the ranges of “5 wt% to 25 wt%,” etc.). Additionally, specified endpoints can be combined to form ranges (e.g., “at least 1 wt% or at least 2 wt%” and “up to 10 wt% or 5 wt%” can be combined to form a range of “1 wt% to 10 wt%” or “1 wt% to 5 wt%” or “2 wt% to 10 wt%” or “2 wt% to 5 wt%”).

[0023] Figure 1A flowchart of an embodiment of a method 100 for preparing an electrode slurry is provided. In step 101, a conductive material 102 is mixed with a dispersant 103 and a plasticizer 105 to obtain a mixture 106. In step 108, the mixture 106 is combined with an active material 107 to obtain a mixture 109. In a final combination step 111, the mixture 109 is combined with a fluoropolymer additive binder 110 (hereinafter binder 110) to obtain an electrode slurry 112.

[0024] Figure 2 This is an example diagram of an electrode (anode or cathode) prepared using electrode paste 112. Electrode paste 112 can be applied to current collector 202 to form an electrode (anode or cathode). Figure 2 In the illustrated embodiment, electrode 200 includes current collector 202 and active layer 201. Active layer 201 includes active material 107, polymer additive binder 110, and conductive element 102.

[0025] Compared to Figure 1 The steps shown in Method 100 can be performed in an alternative sequence. The conductive material 102, dispersant 103, plasticizer 105, and binder 110 can be added in any order or in any combination of the mixture components. In some embodiments, the conductive material 102, dispersant 103, solvent 104, plasticizer 105, and binder 110 can each be added individually or in batches during Method 100. For example, binder 110 can be combined with active material 107 and then added to mixture 106. In another embodiment, active material 107, binder 110, and plasticizer 105 can be combined into a mixture, and conductive material 102 can be added in the final step of Method 100.

[0026] For method 100, the dispersant 103 and plasticizer 105 components may be omitted or added to the various steps. For example, dispersant 103 and plasticizer 105 may be omitted in step 101. In embodiments where components are added, dispersant 103 and / or plasticizer 105 may be added at step 108 and / or step 111.

[0027] The processing of each step of the method 100 can include introducing mechanical energy into the combination of components to provide a mixture of the components. In some embodiments, the component materials are uniformly dispersed in the mixture. Suitable processes that introduce mechanical energy include sonication, vortexing, centrifugation, kneading, high shear mixing, and combinations thereof. The mechanical energy introduced into the mixture can be at least 0.4 kilowatt hours per kilogram (kWh / kg), 0.5 kWh / kg, 0.6 kWh / kg, 0.7 kWh / kg, 0.8 kWh / kg, 0.9 kWh / kg, 1.0 kWh / kg, or more, for example. For example, the mechanical energy introduced into the mixture per kilogram of the mixture can be from 0.4 kWh / kg to 1.0 kWh / kg. Suitable mixing devices include high shear mixers, twin screw mixers, ultrasonic bath mixers, acoustic mixers, and the like. Alternatively, a planetary mixer can be used, such as a multi-shaft (e.g., three-shaft or more) planetary mixer. The planetary mixer can have multiple blades, such as two or more mixing blades and one or more (e.g., two, three, or more) dispersing blades, such as disc dispersing blades.

[0028] Conductive material

[0029] The conductive material 102 can be a carbonaceous conductive material. For example, the carbonaceous conductive material can be a high aspect ratio carbon element. The term "high aspect ratio carbon element" refers to a carbonaceous element in which the size of one or more dimensions ("large dimension") is significantly greater than the size of the transverse dimensions ("small dimension"). The high aspect ratio carbon element can include a substantially cylindrical network of carbon atoms. The conductive material can include carbon nanotubes or multi-beam carbon nanotubes.

[0030] In an embodiment, the conductive material used in the anode and / or cathode can include graphite platelets, carbon black, or combinations thereof. In an embodiment, the graphite platelets are high aspect ratio graphite platelets in which at least one dimension is greater than any other dimension. The graphite platelets can be naturally occurring or commercially synthesized platelets. The graphite platelets are particulate and can be elliptical in shape. The aspect ratio of these graphite platelets can be from 2: 1 to 20: 1, specifically 5: 1 to 12: 1.

[0031] The conductive material 102 can form a conductive percolating network that can transport electrical current between any two separate points located on the surface of the solid active layer 201. In other words, electrical current can be transported from one surface or end of the active layer 201 to the opposite surface or end through physical contact or electron hopping between the conductive elements in the electrode active layer 201. The percolating network can contain voids between the high aspect ratio carbon elements that can contain or hold electrode active material. The high aspect ratio conductive material can be substantially oriented in the electrode active layer 201 in a direction substantially parallel to the current collector 202 to facilitate the conduction of electrical current from one end of the electrode to the other, while still maintaining some small orientation across the thickness of the active layer 201.

[0032] The conductive material 102 can be present in the mixture in an amount of 0.1 wt% to 1.3 wt%, or 0.15 wt% to 1.2 wt%, or 0.3 wt% to 1 wt%, based on the total weight of the electrode slurry 112. The conductive material 102 can be present in the active layer 201 in an amount of 0.2 wt% to 3.5 wt%, or 0.3 wt% to 3 wt%, or 0.5 wt% to 2 wt%, based on the total weight of solids in the active layer 201.

[0033] The high aspect ratio carbon elements can be single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWNTs), thin-walled nanotubes (TWNTs), carbon black, carbon nanofibers, carbon nanotube fibers, porous carbon, or a mixture of different types.

[0034] The single-walled carbon nanotubes can have an outer diameter of 0.5 nanometers (nm) to 5.0 nm, specifically 1.0 nm to 3.5 nm. The single-walled carbon nanotubes can have an aspect ratio (length to diameter) of greater than about 2.0, specifically greater than 5.0, specifically greater than 10.0, greater than 50, and more specifically greater than 100. In exemplary embodiments, the single-walled carbon nanotubes can have an average aspect ratio of 5 to 200.

[0035] The single-walled carbon nanotubes can have a length of greater than 6 nm, specifically greater than 10 nm, specifically greater than 15 nm, specifically greater than 30 nm, specifically greater than 50 nm, more specifically greater than 100 nm, specifically greater than 1 micrometer (pm), specifically greater than 5 pm, specifically greater than 10 pm, and more specifically greater than 15 pm to at least 200 pm. In exemplary embodiments, the single-walled carbon nanotubes can have an average length of 10 nm to 20 micrometers (pm), specifically 20 nm to 15 pm.

[0036] Single-walled carbon nanotubes can be present in the mixture of conductive material, binder material, and electrode active material and plasticizer in an amount of 0.1 wt% to 0.3 wt%, specifically 0.15 wt% to 0.25 wt%, based on the total weight of the electrode slurry 112. For cathode electrode slurries, single-walled carbon nanotubes can be present in the mixture of conductive material, binder material, electrode active material, and solvent in an amount of 0.01 wt% to 0.3 wt%, specifically 0.02 wt% to 0.15 wt%, based on the total weight of the electrode slurry 112.

[0037] Single-walled carbon nanotubes can be present in the electrode active layer 201 in an amount of 0.2 wt% to 0.6 wt%, specifically 0.3 wt% to 0.5 wt%, based on the total weight of the electrode active layer 201 (substantially free of volatile materials). By "substantially free" it is meant that the content of volatile materials is less than about 0.0001 weight percent (wt%) to about 0.1 wt%, about 0.001 wt% to about 0.01 wt%, or about 0.05 wt%, based on the total weight of the active layer 201.

[0038] In another embodiment, the SWNTs can comprise a mixture of metallic nanotubes and semiconducting nanotubes. Metallic nanotubes are those that exhibit electrical properties similar to metals, while semiconducting nanotubes are those that have semiconducting electrical properties. In general, the way in which the graphene sheets are curled results in nanotubes of various helical structures. Zigzag and armchair-shaped nanotubes constitute two of the possible identifications. To minimize the number of SWNTs used in the composition, it is generally desirable for the composition to comprise as large a proportion of metallic SWNTs as possible. The SWNTs can be used in the composition to comprise metallic nanotubes in an amount greater than or equal to about 1 wt%, specifically greater than or equal to about 20 wt%, more specifically greater than or equal to about 30 wt%, even more specifically greater than or equal to about 50 wt%, and most specifically greater than or equal to about 99.9 wt%, of the total weight of the SWNTs. In certain cases, the SWNTs used in the composition comprise semiconducting nanotubes in an amount greater than or equal to about 0.1 wt%, greater than or equal to about 20 wt%, greater than or equal to about 30 wt%, or greater than or equal to about 50 wt%, of the total weight of the SWNTs.

[0039] In an embodiment, the single-walled carbon nanotubes in metallic form are present in the electrode active layer 201. The electrode active layer 201 referred to herein can be a cathode active layer or an anode active layer. For an anode active layer, the SWNTs in metallic form can be present in an amount of 0.2 wt% to 0.6 wt%, specifically 0.3 wt% to 0.5 wt%, based on the total weight of the electrode active layer 201 (substantially free of volatile matter). For a cathode active layer, the SWNTs in metallic form can be present in an amount of 0.05 wt% to 0.2 wt%, based on the total weight of the electrode active layer 201 (substantially free of volatile matter).

[0040] The number of carbon walls in the multi-walled carbon nanotubes can be 2 or more, 5 or more, 10 or more, 50 or more. The multi-walled carbon nanotubes can on average comprise 3 to 15 layers, 4 to 12 layers, 5 to 10 layers, 6 to 8 layers.

[0041] The D50 particle size distribution of the carbon black or porous carbon can be 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 m 2 / g, specifically at least 500 m 2 / g. The carbon black or porous carbon can be present in the electrode active layer in an amount of 0.2 wt% to 1.0 wt%, specifically 0.3 wt% to 0.5 wt%, based on the total weight of the electrode active layer 201 (substantially free of volatile matter).

[0042] The active layer 201 (see Figure 2 ) can comprise multi-walled carbon nanotubes and single-walled carbon nanotubes. The multi-walled carbon nanotubes swell more than the single-walled carbon nanotubes when wetted with an electrolyte in an energy storage device in which the electrode 200 is located. For example, the multi-walled carbon nanotubes can swell at least 15% or at least 25% or at least 50% more than the single-walled carbon nanotubes when wetted with an electrolyte in an energy storage device in which the electrode 200 is located. For example, the length of the multi-walled carbon nanotubes can swell at least 15%, or at least 25% or at least 50% more than the length of the single-walled carbon nanotubes when wetted with an electrolyte. As another example, the multi-walled carbon nanotubes can swell up to 50% when wetted (e.g., the length of the multi-walled carbon nanotubes increases by 50% after wetting with an electrolyte, and / or the diameter of the multi-walled carbon nanotubes increases by 50% after wetting, etc.).

[0043] The outer diameter of the multi-walled carbon nanotubes can be from 2.0 nm to 50 nm, from 5.0 nm to 40 nm, or from 6 nm to 10 nm. The length of the multi-walled carbon nanotubes can be greater than 10 nm, greater than 15 nm, greater than 30 nm, greater than 50 nm, greater than 100 nm, greater than 500 nm, greater than 1 pm, greater than 5 pm, greater than 10 pm, or greater than 15 pm. At the same time, the average length of the multi-walled carbon nanotubes can be up to 25 pm or up to 20 pm. In exemplary embodiments, the average length of the multi-walled carbon nanotubes is from 10 nm to 20 pm or from 20 nm to 15 pm. The aspect ratio (length to diameter) of the multi-walled carbon nanotubes can be greater than 5.0, greater than 10.0, greater than 50, greater than 100, or greater than 500. In some embodiments, the aspect ratio of the multi-walled carbon nanotubes can be up to 10,000.

[0044] The electrodes comprising multi-walled carbon nanotubes can be relatively long compared to the multi-walled carbon nanotubes included in related art electrodes. It has been discovered that the use of relatively long multi-walled carbon nanotubes in electrodes has beneficial mechanical and / or electrical properties. For example, multi-walled carbon nanotubes provide relatively good power at low density. As another example, shorter multi-walled carbon nanotubes do not generally swell (e.g., expand) as much as longer multi-walled carbon nanotubes. Thus, the use of shorter multi-walled carbon nanotubes loses (or reduces) some of the beneficial properties associated with the swelling of carbon nanotubes. As an extreme example, carbon black does not exhibit swelling because carbon black is simply a carbon particle without entanglement, such as the entanglement exhibited by a group of multi-walled carbon nanotubes. An indication that a certain amount of multi-walled carbon nanotubes have a length beyond a threshold length and thus have sufficient swelling properties is an observation during the calendering process - a relatively large amount of pressure or effort associated with the calendering of the active layer applied to the foil indicates that the collective swelling (e.g., average swelling) of the multi-walled carbon nanotubes in the active layer will meet certain performance thresholds. However, multi-walled carbon nanotubes are generally difficult to process.

[0045] The processing of the multi-walled carbon nanotubes associated with the preparation / forming of the active layer and / or electrode is more gentle than the processes of related art electrodes. Thus, according to various embodiments, the process preserves longer multi-walled carbon nanotubes (e.g., fewer multi-walled carbon nanotubes are crushed, broken, fractured, etc.). In some embodiments, the active layer 201 of the electrode comprises a group of multi-walled carbon nanotubes having an average length that is greater than the average length of the multi-walled carbon nanotubes in related art electrodes.

[0046] According to various embodiments, the length distribution of the set of multiwall carbon nanotubes is skewed toward the nominal length of the multiwall carbon nanotubes. For example, the multiwall carbon nanotubes are processed and / or applied in a manner that reduces or minimizes breakage or fragmentation of the multiwall carbon nanotubes. The lengths of the multiwall carbon nanotubes in the high aspect ratio carbon element network are typically the nominal length of the multiwall carbon nanotubes, or the lengths of such multiwall carbon nanotubes tend to be more heavily skewed toward the nominal length.

[0047] In some embodiments, at least 75% of the multiwall carbon nanotubes within the high aspect ratio carbon element network are within 10% of the nominal length (e.g., 13.4 pm to about 15 pm). In some embodiments, at least 75% of the multiwall carbon nanotubes within the high aspect ratio carbon element network are at least 12 pm in length. In some embodiments, at least 75% of the multiwall carbon nanotubes within the high aspect ratio carbon element network are at least 13 pm in length. In some embodiments, at least 50% of the multiwall carbon nanotubes within the high aspect ratio carbon element network are within 10% of the nominal length (e.g., 13.4 pm to about 15 pm). In some embodiments, at least 50% of the multiwall carbon nanotubes within the high aspect ratio carbon element network are at least 12 pm in length. In some embodiments, at least 50% of the multiwall carbon nanotubes within the high aspect ratio carbon element network are at least 13 pm in length.

[0048] The multiwall carbon nanotubes can be present in the electrode slurry 112 in an amount of 0.3 wt% to 1.0 wt%, specifically 0.4 wt% to 0.9 wt%, based on the total weight of the electrode slurry 112. The multiwall carbon nanotubes are present in the solid active layer 201 in an amount of 0.8 wt% to 2.6 wt%, specifically 1.0 wt% to 1.8 wt%, based on the total weight of the solid active layer (which is substantially free of volatile matter).

[0049] In examples that use both multiwall carbon nanotubes and single wall carbon nanotubes, the ratio of the weight of the multiwall 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.

[0050] In one example, the three-dimensional network of high aspect ratio conductive material 102 comprises carbon nanotubes, and the carbon nanotubes are only multiwall carbon nanotubes and / or fragments of such carbon nanotubes.

[0051] In another example, the amount of multiwall carbon nanotubes present in the electrode slurry 112 or the solid active material layer 201 is at least twice the amount of single wall carbon nanotubes, based on the total weight of the conductive material 102.

[0052] In an embodiment, the carbon nanotubes can comprise randomly dispersed carbon nanotubes with brush-like oriented nanotube agglomerates dispersed therein. The brush-like oriented nanotubes are randomly dispersed in the randomly dispersed carbon nanotubes, but within each brush-like agglomerate, the nanotubes are aligned. The length of the aligned nanotubes in the brush-like agglomerates can be greater than the thickness of the active layer (i.e., cathode active layer or anode active layer).

[0053] The network of the three-dimensional network of high aspect ratio conductive material 102 can comprise at least 99% by weight of carbon.

[0054] In addition to the high aspect ratio carbon elements (carbon nanotubes), the conductive material can optionally comprise graphite flakes, carbon black, or a combination thereof.

[0055] In addition to carbon nanotubes, carbon black or porous carbon can also be used. These carbon materials can be high surface area carbon with a surface area greater than 50 square meters per gram (m 2 / g, specifically greater than 200 m 2 / g, and more specifically greater than 500 m 2 / g. An example of high surface area carbon black is KETJEN Black. The carbon material is optional and can be present in the solid active layer 201 in an amount of 0.5 wt% to 2.0 wt%, specifically 0.8 wt% to 1.6 wt%, based on the total weight of the active layer 201 (substantially free of volatile matter). While the presence of high aspect ratio carbon nanotubes is beneficial for electrical conductivity and battery cell rate performance, 1D carbon materials (carbon black or porous carbon) are generally less expensive and can achieve the best slurry rheology at high slurry solid content.

[0056] The three-dimensional network of high aspect ratio conductive material 102 can comprise an electrically interconnected network of carbon elements exhibiting connectivity above a percolation threshold, and wherein the network defines one or more high conductive paths with a length greater than 100 pm. The percolation threshold is a threshold at which conductive elements are in contact with each other to provide an electrically conductive network measured across any two points on any surface of the network.

[0057] Dispersant

[0058] The dispersant 103 can be a polymeric binder selected from a variety of polymers. For example, the dispersant 103 can be carboxymethyl cellulose (CMC), styrene butadiene rubber (SBR), block copolymers (such as lignosulfonate, naphthalenesulfonate), polyvinylpyrrolidone and copolymers thereof, or combinations thereof. Suitable polymeric binders can include one or more of the polymeric binders listed below for the binder 110, and will not be detailed here for the sake of brevity. The dispersant 103 can be present in the electrode slurry 112 in an amount of about 0.05 wt% to about 0.3 wt%, or about 0.1 wt% to about 0.2 wt%, based on the total weight of the electrode slurry 112. The dispersant 103 can function to facilitate material dispersion to reduce agglomeration during electrode slurry 112 preparation. In some embodiments, the dispersant 103 is omitted in the processing step 101 and method 100.

[0059] Plasticizer

[0060] The plasticizer 105 in the electrode slurry 112 can improve the flowability of the materials within the mixture. Suitable plasticizers include propylene carbonate, ethylene carbonate, dimethylsulfoxide (DMSO), sulfolane, polyethylene glycol tert-octylphenyl ether, and gamma-butyrolactone. In some embodiments, the plasticizer 105 is omitted in the processing step 101. In alternative embodiments, the plasticizer 105 is added at step 108 and / or step 111. When the plasticizer 105 is added at more than one step of the method 100, the plasticizer 105 at each step can be the same or different. In some embodiments, more than one plasticizer can be added at a single step of the method 100. The plasticizer 105 can be present in the electrode slurry 112 in an amount of about 1 wt% to about 25 wt%, or about 10 wt% to about 20 wt%, based on the total weight of the electrode slurry 112. The plasticizer 105 can function to facilitate the flowability of the polymer chains in the active layer 201.

[0061] In some embodiments, the plasticizer 105 is a liquid, semi-solid, gel, or solid, and is not removed from the active layer 201 during electrode preparation. In some embodiments, the plasticizer 105 is present in the active layer 201 in an amount of 0.1 wt% to 20 wt% of the total weight of the active layer 201 (substantially free of volatile materials).

[0062] Active material

[0063] The active material 107 can be an active material of an anode or a cathode.

[0064] Anode active material

[0065] For example, the anode active material can include silicon (Si), germanium (Ge), tin (Sn), lead (Pb), antimony (Sb), bismuth (Bi), zinc (Zn), aluminum (Al), titanium (Ti), nickel (Ni), cobalt (Co), cadmium (Cd); alloys or two or more of these or alloys thereof with other elements; oxides, carbides, nitrides, sulfides, phosphides, selenides, and tellurides of these metals and mixtures thereof or lithium-containing composites; salts and hydroxides of Sn; lithium titanate, lithium manganate, lithium aluminate, lithium-containing titanium oxides, lithium transition metal oxides; pre-lithiated versions thereof; particles of Li, Li alloys or surface stabilized Li with at least 60 wt% lithium or combinations thereof. Instead of or in addition to the anode active material, the active material can include graphite. As one example, the anode active material can include silicon oxide and / or carbon silicon oxide. Such anode active materials including silicon oxide or carbon silicon oxide can further include graphite. In other embodiments, the anode active material can include elemental microparticles or nanoparticles of elemental Si, either pristine or engineered, or alone or in combination with other anode active materials.

[0066] In an embodiment, the active material used in the anode is a lithium-based active material. Examples of lithium-based active materials are Li x Si y O z wherein x is 1 to 15, specifically 2 to 7, y is 0 to 4, specifically 1 or 2, and z is 0 to 9, specifically 1 to 5. SiO is synthesized by mixing silicon and silicon dioxide at a 1:1 molar ratio, then subliming the mixture to collect amorphous SiO (a-SiO) material. Since silicon atoms in a-SiO are randomly distributed, their valence can be 0, 1+, 2+, 3+, and 4+ depending on the bonding condition with different numbers of oxygen atoms. Some silicon atoms cluster and form tiny silicon crystals surrounded by other amorphous substances whose Si-O bonds have different silicon valences. In a LIB, these tiny silicon crystals in a-SiO react with Li+ions and form Li 15 Si4, as an active material that stores energy. Due to the nanoscale of the tiny silicon crystals, no pulverization occurs after lithiation; thus, good reversibility can be obtained.

[0067] Examples of lithium-based active materials include Li 15 Si4, Li2SiO3, Li2Si2O5, Li6Si2O7, Li4SiO4, Li2O, or combinations thereof.

[0068] In an embodiment, the lithium-based active material can be blended with a carbonaceous material to form a Li-SiOx-C active material. In other words, the active material can comprise lithium, silicate, and carbon. Carbon in the form of carbon black, carbon nanotubes, or graphite can be blended with Li x Si y O z where x, y, and z values are detailed above) can be blended and pulverized to form aggregates and agglomerates of Li-SiOx-C active material.

[0069] In manufacturing the Li-SiOx-C active material, elemental silicon (Si) can be first reacted with a silicate material (SiOx) and blended. The combination of silicon and silicon dioxide is subjected to a reaction and milling process to form a powder. Carbon is added to this powder in a carbon coating process, and lithium is added to this powder in a lithium doping process. After the process of adding carbon and lithium, the resulting Li-SiOx-C material will be subjected to a classification process to form the final usable anode active material, referred to as Li-SiO with a carbon coating. The relative density of the material formed is about 2.1 grams per cubic centimeter (g / cm 3 ).

[0070] Lithium can be added in elemental form or in compound form. Some of these lithium compounds are listed herein. The D50 particle size of the Li-SiOx-C particles prepared in this manner is about 6 pm to about 9 pm. The BET surface area of the Li-SiOx-C material formed can be about 3 m 2 / g to about 4 m 2 / g, and the carbon content is about 3 wt% to about 4 wt%. The initial charge specific capacity of a battery cell (also referred to as an energy storage device) having a Li-SiOx-C anode relative to Li / Li+at 5 millivolts (mV) can be about 1500 mAh / g to about 1600 mAh / g, and the initial discharge specific capacity of a battery cell having a Li-SiOx-C anode material relative to Li / Li+at 2.0 volts (V) can be about 1400 mAh / g to about 1500 mAh / g, and the initial coulombic efficiency is about 90% to about 94%; and the initial discharge specific capacity of a battery cell having a Li-SiOx-C material relative to Li / Li+at 1.0 V can be about 1350 mAh / g to about 1400 mAh / g, and the initial coulombic efficiency is about 87% to about 89%.

[0071] The manufacture of Li-SiOxand Li-SiOx-C active materials and corresponding electrodes are detailed in U.S. Patent No. 9,825,290 B2 and U.S. Patent Application No. 2019 / 0237761 Al, the entireties of which are incorporated by reference.

[0072] Based on the total weight of the active layer 201 (which is substantially free of volatile substances), the anodic active material may be present in the active layer 201 in an amount of approximately 40 wt% to approximately 90 wt%.

[0073] Cathode active materials

[0074] Cathode active materials can comprise lithium cobalt oxide (LCO, sometimes called "lithium cobalt oxide" or "spodumene"). Examples of LCO formulations include LiCoO2; lithium cobalt manganese aluminum oxide (NCMA); lithium nickel manganese cobalt oxide (NMC, with the variant LiNiMnCo); lithium manganese oxide (LMO, with the variants LiMn2O4, Li2MnO3, etc., or combinations thereof); and lithium titanate oxide (LTO, with a variant Li4Ti5O). 12 Lithium iron phosphate oxide (LFP, with a variant LiFePO4); lithium nickel cobalt aluminum oxide (and its variant NCA); lithium manganese iron phosphate (LMFP); sulfurized poly(n-butyl methacrylate); lithium manganese iron phosphate (LMFP); metal-doped lithium cobalt oxides (e.g., aluminum-doped LCO); sulfurized poly(acrylonitrile); and other similar materials and combinations thereof. Other variants of the foregoing may also be included.

[0075] In one embodiment, the cathode active material may comprise NMC, NCA, NCMA, or a combination thereof.

[0076] When using NMC as the cathode active material, nickel-rich NMC can be used. For example, a variant of NMC can be LiNi. x Mn y Co (1-x-y) Where x is equal to or greater than about 0.7, 0.75, 0.80, 0.85 or greater, y is equal to or greater than 0.1, 0.15, 0.2 or 0.25, and x + y is less than 1. For example, NMC811 can be used when x is about 0.8 and y is about 0.1. Alternatively, the cathode active material may include lithium nickel manganese cobalt oxide (LiNi). x Mn y Co z O2). Variants of this formulation that can be used in the active material layer include NMC111 (described in detail below) and NMC532 (LiNi). 0.5 Mn 0.3 Co 0.2 O2), NMC622 (LiNi) 0.6 Mn 0.2 Co 0.2 O2) or combinations thereof.

[0077] In an embodiment, NMC91 can be used as a cathode active material. NMC91 comprises 91 mole percent or more of nickel. An example of NMC91 is LiNi 0.91 Co 0.06 Mn 0.03 O2. Li[Ni 1-x Co x Al y ]O2(NCA) can also be used as a cathode active material. An example of NCA is NCA89.

[0078] In yet another embodiment, the cathode active material can be a NCMA material. An example of NCMA is Li[Ni 0.89 Co 0.05 Mn 0.05 Al 0.01 ]O2, also known as NCMA89.

[0079] In an embodiment, the cathode active material can also include a combination of nickel, manganese, and cobalt. Lithium nickel manganese cobalt oxide (LiNiMnCoO2), abbreviated as NMC, has strong overall performance, excellent specific energy, and the lowest self-heating rate among all mainstream cathode powders. The NMC powder can comprise nickel in an amount of 20 wt% to 40 wt%, manganese in an amount of 20 wt% to 40 wt%, and cobalt in an amount of 20 wt% to 40 wt%, based on the total weight of the NMC blend. While the term “NMC powder” can refer to a variety of blends, it is desirable to use a blend comprising 33 wt% nickel, 33 wt% manganese, and 33 wt% cobalt. This blend is sometimes referred to as 1-1-1 (NMC111) and can be used for applications that use frequent cycling (automotive, energy storage) because the cobalt content of the nickel, manganese, and cobalt rich combination (NMC) of nickel, manganese, and cobalt is low, thereby reducing the cost of the material. The NMC powder can comprise nickel in an amount of 20 wt% to 40 wt%, manganese in an amount of 20 wt% to 40 wt%, and cobalt in an amount of 20 wt% to 40 wt%, based on the total weight of the NMC blend. Lithium nickel manganese cobalt oxide (LiNiMnCoO2) has strong overall performance, excellent specific energy, and the lowest self-heating rate among all mainstream cathode powders. Lithium-rich NCM materials, such as BASF’s 307, 424, and 523, can also be used as a cathode active material.

[0080] Generally, adding a load-increased active material to the cathode (measured as a function of the total weight of the cathode) increases the area capacity and specific energy level of the cathode.

[0081] The cathode active material can be present in the mixture used to form the cathode in an amount of 45 wt% to 85 wt%, specifically 60 wt% to 70 wt%, based on the total weight of the cathode slurry (a mixture used to make a cathode active layer containing a cathode binder material, a cathode active material, and a cathode conductive material). The cathode active material is present in the cathode active layer in an amount of 95 wt% to 99 wt%, based on the total weight of the cathode active layer (substantially free of volatile materials).

[0082] Binder

[0083] At step 111, in some embodiments, a binder 110 can be applied as a surface treatment to the mixture 109. The binder 110 can be added at step 101, step 108, step 111, and / or a combination thereof.

[0084] Anode polymer binder

[0085] In one embodiment, the anode binder is water-soluble or can be dispersed in an aqueous solution (e.g., an emulsion). The water-soluble or water-dispersible anode binder comprises a first polymer comprising a first repeat unit comprising an ether linkage and / or comprising a polyol along a chain backbone. Polymers with ether linkages along a chain backbone are generally referred to as polyethers and can be used as binders in the active layer in the form of a homopolymer, a copolymer, or a blend with other compatible homopolymers or copolymers.

[0086] In another embodiment, the anode binder can include a first polymer comprising a first repeat unit comprising a polyol. A polyol is an organic compound that contains multiple hydroxyl groups. Polyols containing two, three, and four hydroxyl groups are diols, triols, and tetraols, respectively.

[0087] When the anode binder comprises a copolymer, the first polymer can be covalently or ionically bonded to a second polymer derived from a second repeat unit comprising a (meth)acrylic acid / (meth)acrylate monomer. Other second polymers are also listed below (which can be used in place of polymers derived from (meth)acrylic acid / (meth)acrylate monomers). It is desirable for the anode binder to be water-soluble or soluble in an aqueous solution. In another embodiment, it is desirable for the anode binder to be dispersible in water or an aqueous solution.

[0088] The copolymer can be a random copolymer, a block copolymer, an alternating copolymer, a graft copolymer, a star block copolymer, a gradient copolymer, a dendrimer, or a combination thereof. The copolymer can be a linear polymer, a branched polymer, or can be crosslinked.

[0089] Polyethers useful as binders have the structure of formula (1):

[0090] (1)

[0091] where R1and R2may independently be hydrogen or an alkyl group having 1 to 5 carbon atoms, n is 1 to 4, and m is 50 to 100,000, specifically 200 to 50,000. Examples include polyformal having the structure of formula (2):

[0092] (2),

[0093] polyethylene oxide having the structure of formula (3)

[0094] (3)

[0095] polytetramethylene oxide having the structure of formula (4)

[0096] (4)

[0097] polypropylene glycol having the structure of formula (5)

[0098] (5)

[0099] polybutylene glycol having the structure of formula (6)

[0100] (6) or combinations thereof, where m has the meaning indicated above for formula (1). The combinations can include blends or copolymers of the foregoing structures.

[0101] As noted above, instead of or in addition to polyethers, the binder can include polyols. Examples of polyols include polyether polyols shown below.

[0102]

[0103] where n is 50 to 100,000, specifically 100 to 50,000. Blends of the above polyethers and polyols can also be used.

[0104] The first polymer can have a molecular weight of 1,000 grams per mole (g / mol) to 1,000,000 g / mol, specifically 5,000 g / mol to 500,000 g / mol, as measured using gel permeation chromatography with polystyrene standards.

[0105] Other polyols that can be used as binders include polycaprolactone polyols, polyurethanes (obtained by combining polyols with polyisocyanates), polycarbonate polyols, and acrylic polyols.

[0106] In an embodiment, the polyether or polyol detailed above can be combined with a second repeat unit derived from (meth)acrylic acid / (meth)acrylate polymerization to form a copolymer.

[0107] The second repeat unit is derived from the polymerization of an ethylenically unsaturated monomer comprising a hydrophilic pendant group. In an embodiment, the hydrophilic pendant group is a carboxylic acid group or a carboxylate salt group. The structure of the second repeat unit is derived from the polymerization of a monomer represented by formula (7):

[0108] (7)

[0109] wherein R1is hydrogen or an alkyl group having 1 to 10 carbon atoms. The carboxylic acid can be neutralized with a metal ion (e.g., sodium, zinc, etc.) to produce a polymer salt (commonly referred to as an ionomer). Examples of polymeric acrylic acids include polyacrylic acid, polymethyl acrylate, polyethyl acrylate, polypropyl acrylate, etc., or combinations comprising at least one of the foregoing acrylates.

[0110] In an embodiment, the second repeat unit is derived from a monomer having a structure represented by formula (8):

[0111] (8)

[0112] wherein R1is hydrogen or an alkyl group having 1 to 10 carbon atoms, and R2is C 1-10 alkyl, C 3-10 cycloalkyl, or C 7-10 aralkyl group. Examples of (meth)acrylates are polymethyl methacrylate, polyethyl methacrylate, polypropyl methacrylate, polyethyl acrylate, polyaryl methacrylate, etc., or combinations comprising at least one of the foregoing acrylates. The term “(meth)acrylate” means to consider either an acrylate or a methacrylate, unless otherwise specified.

[0113] As noted above, the acrylate is derived from a monomer having at least one fluorine atom substituent and having a structure represented by formula (9):

[0114] (9)

[0115] wherein R1is hydrogen or an alkyl group having 1 to 10 carbon atoms, and R3is C 2-10 fluoroalkyl group. Examples of compounds having the structure of formula (3) are trifluoroethyl methacrylate and dodecafluoroheptyl methacrylate.

[0116] In an embodiment, the polyether and / or polyol can be reacted with a non-(meth)acrylic acid / (meth)acrylate second polymer, such as a polyacetal, polycarbonate, polyalkyd, polystyrene, polyolefin, polyester, polyamide, polyaramid, polyamide-imide, polyarylate, polyurethane, epoxy, phenolic, silicone, polyarylsulfone, polyethersulfone, polyphenylene sulfide, polysulfone, polyimide, polyetherimide, polytetrafluoroethylene, polyether ketone, polyether ether ketone, polyether ketone ketone, polybenzoxazole, polyoxadiazole, polybenzothiazin phenothiazine, polybenzothiazole, polypyrazinoquinoxaline, para-phenylene polyimide, polyquinoxaline, polybenzimidazole, polyoxindole, polyoxoisoindoline, polydioxoisoindoline, polytriazine, polyprydazine, polypyrazine, polypyridine, polypyridizine, polytriazole, polyprazole, polycarborane, polyoxabicyclononane, polydibenzofuran, polyphthalide, polyacid anhydride, polyvinyl ether, polyvinyl sulfide, polyvinyl alcohol, polyvinyl ketone, polyvinyl halide, polyvinyl nitrile, polyvinyl ester, polysulfonic acid ester, polysulfide, polythioester, polysulfone, polysulfonamide, polyurea, polyphosphazene, polysilazane, polypropylene, polyethylene, polyethylene terephthalate, polyvinylidene fluoride, polysiloxane, or combinations thereof.

[0117] The second polymer can have a molecular weight of 1,000 g / mol to 1,000,000 g / mol, specifically 5,000 g / mol to 500,000 g / mol, as measured using gel permeation chromatography with polystyrene standards.

[0118] The polyether and / or polyol can be reacted with the acrylic acid / acrylate (or other second polymer listed above) to form a water-soluble copolymer binder. In another embodiment, the polyether and / or polyol can be blended with the acrylic acid / acrylate (or other second polymer listed above) to form a water-soluble blend.

[0119] When the polyether and / or polyol is reacted with the (meth)acrylic acid / (meth)acrylate (or other second polymer listed above) to form a copolymer binder, the polyether and / or polyol is present in an amount of 5 mole percent (mol%) to 95 mol%, specifically 10 mol% to 90 mol%, and more specifically 20 mol% to 80 mol%, based on the total moles of the copolymer. The poly(meth)acrylic acid / poly(meth)acrylate (or other second polymer listed above) is present in the copolymer in an amount of 95 mol% to 5 mol%, specifically 90 mol% to 10 mol%, and more specifically 80 mol% to 20 mol%, based on the total moles of the copolymer.

[0120] The copolymer can be made by polymerization techniques of ethylenically unsaturated monomers, such as addition polymerization, condensation polymerization, or ionic polymerization. The polymerization can be, for example, solution polymerization or emulsion polymerization.

[0121] If desired, the polymer can include cross-linking functionality, or a cross-linking agent can be added, such that the binder polymer can be cross-linked prior to completion of the preparation of the electrode active layer.

[0122] When used in the blend, the polyether and / or polyol is present in an amount of 20 wt% to 80 wt%, specifically 30 wt% to 70 wt%, based on the total weight of the blend. The poly(meth)acrylic acid / poly(meth)acrylate is present in an amount of 80 wt% to 20 wt%, specifically 70 wt% to 30 wt%, based on the total weight of the blend.

[0123] An example of a suitable binder for the anode is a copolymer of polyether and polyacrylic acid.

[0124] The binder 110 can be present in the anode electrode slurry in an amount of 3 wt% to 12 wt%, based on the total weight of the anode electrode slurry (absence of volatile matter). The binder 110 can be present in the anode active layer in an amount of 5 wt% to 10 wt%, based on the total weight of the dry anode active layer (absence of volatile matter).

[0125] Cathode binder

[0126] The cathode polymer binder (for the cathode) can include a polyamide, a copolymer of polyacrylic acid, or an acrylate copolymer. The cathode polymer binder can also include a second cathode polymer binder, such as polyvinylpyrrolidone (PVP).

[0127] The polyamide can include an aliphatic polyamide, an aromatic polyamide, or a combination thereof. In one embodiment, the polyamide includes a class of resins known as nylons, which are characterized by the presence of amide groups (-C(O)NH-). Any amide-containing polymer can be used, alone or in combination: Nylon-6 and Nylon-6,6 are suitable polyamide resins, available from various commercial sources. However, other polyamides, such as copolymers of nylon-4, nylon-4,6 (PA 46), nylon-12, nylon-6,10, nylon-6,9, nylon-6,12, nylon-9T, nylon-6,6 and nylon-6, nylon 610 (PA610), nylon 11 (PA11), nylon 12 (PA12), nylon 6-3-T (PA 6-3-T), polyarylamide (PA MXD 6), polyphthalamide (PPA), and / or polyether block amide, as well as others such as amorphous nylon, can also be useful. Mixtures of various polyamides, as well as various polyamide copolymers, are also useful.

[0128] Polyamides can be obtained by a variety of well-known processes, such as those described in U.S. Pat. Nos. 2,071,250; 2,071,251; 2,130,523; 2,130,948; 2,241,322; 2,312,966; and 2,512,606. For example, nylon-6 is the polymerization product of caprolactam. Nylon-6,6 is the condensation product of adipic acid and 1,6-diaminohexane. Likewise, nylon 4,6 is the condensation product of adipic acid and 1,4-diaminobutane. In addition to adipic acid, other useful diacids for making nylons include azelaic acid, sebacic acid, dodecanedioic acid, and terephthalic acid and isophthalic acid, among others. Other useful diamines include m-xylylene diamine, di-(4-aminophenyl)methane, di-(4-aminocyclohexyl)methane, 2,2-di-(4-aminophenyl)propane, 2,2-di-(4-aminocyclohexyl)propane, and the like. Copolymers of caprolactam with diacids and diamines are also useful.

[0129] Polyamides are generally derived from the polymerization of organic lactams having 4 to 12 carbon atoms. In one embodiment, the lactam is represented by formula (I)

[0130]

[0131] where n is 3 to 11. In one embodiment, the lactam is ε-caprolactam, where n equals 5.

[0132] Polyamides can also be synthesized from amino acids having 4 to 12 carbon atoms. In one embodiment, the amino acid is represented by formula (II)

[0133]

[0134] where n is 3 to 11. In one embodiment, the amino acid is ε-aminocaproic acid, where n equals 5. Polyamides can also be polymerized from aliphatic dicarboxylic acids having 4 to 12 carbon atoms and aliphatic diamines having 2 to 12 carbon atoms. In one embodiment, the aliphatic diamine is represented by formula (III)

[0135] H2N-(CH2) n — NH2(III)

[0136] wherein n is about 2 to about 12. In one embodiment, the aliphatic diamine is hexamethylene diamine (H2N(CH2)6NH2). In one embodiment, the molar ratio of dicarboxylic acid to diamine is 0.66 to 1.5. Within this range, a molar ratio greater than or equal to 0.81 is generally beneficial. In another embodiment, the molar ratio is greater than or equal to 0.96. In yet another embodiment, the molar ratio is less than or equal to 1.22. In still another embodiment, the molar ratio is less than or equal to 1.04. Examples of useful polyamides include nylon 6, nylon 6,6, nylon 4,6, nylon 6,12, nylon 10, or a combination including at least one of the foregoing polyamides.

[0137] Poly(meth)acrylic acid / poly(meth)acrylic esters and copolymers thereof are listed and described above, and for the sake of brevity will not be repeated here.

[0138] The cathode polymer binder is present in an amount of 0.2 wt% to 0.8 wt%, specifically 0.3 wt% to 0.75 wt%, based on the weight of the cathode electrode slurry. The cathode polymer binder is present in the cathode active layer in an amount of 0.4 wt% to 1.0 wt%, specifically 0.5 wt% to 0.9 wt%, based on the total weight of the cathode active layer (substantially free of volatile materials).

[0139] In some embodiments, the cathode active layer includes a second cathode polymer binder, which includes polyvinylpyrrolidone (PVP) or copolymers thereof. In addition to serving as a second cathode polymer binder, PVP or copolymers thereof can serve as a dispersant for the cathode active material and the cathode conductive filler. The PVP copolymer can include repeating molecular units including unsaturated hydrocarbons (olefins) and saturated hydrocarbons (which contain 1-12 carbon atoms). In the copolymer, the percentage of PVP can be in the range of 95 wt% to 10 wt%, specifically 90 wt% to 20 wt%.

[0140] In some embodiments, the cathode active layer includes a (second) cathode polymer binder, which includes hydrogenated nitrile rubber (HNBR). HNBR is obtained by saturating the double bonds in nitrile rubber with hydrogen. HNBR has excellent heat resistance, chemical resistance, and high voltage stability. In some embodiments, HNBR can contain a nitrile content of 10 wt% to 70 wt%, specifically 10 wt% to 50 wt%. The percentage of remaining double bonds in HNBR can be less than 20%.

[0141] When a second cathode polymer binder is present, it can be present in an amount of 20 wt% to 80 wt%, based on the total weight of the cathode polymer binder.

[0142] Electrode slurry

[0143] Electrode slurry 112 is a final slurry mixture having a fluorine content of less than 900 parts per million and a total solids content of 80% to 99% by weight of the total electrode slurry.

[0144] In some embodiments, the viscosity of electrode slurry 112 can be 1,000 centipoise (cps) to 300,000 cps or any sub-range thereof, such as 6,000 cps to 19,000 cps. The viscosity of electrode slurry 112 can vary depending on the intended application technique of electrode slurry 112 during electrode fabrication. For example, for comma coating, the viscosity can be about 1,000 cps to about 200,000 cps. Lip die coating provides coating with slurries exhibiting a viscosity of about 500 cps to about 300,000 cps. Reverse contact coating provides coating with slurries exhibiting a viscosity of about 5 cps to 1,000 cps. In some applications, the respective layer can be formed by multiple passes.

[0145] Active layer 201 includes conductive material 102, active material 107, and binder 100. In some embodiments, active layer 201 also includes a dispersant, a plasticizer, or a combination thereof.

[0146] Active layer 201 can be prepared by coating electrode slurry 112 onto current collector 202 and calendering and drying the coating to yield the final active layer 201. Coating electrode slurry 112 onto current collector 202 can be performed by slot die coating, spin coating. In some embodiments, active layer 201 can be prepared by casting a self-supporting film from electrode slurry 112, disposing the film onto current collector 202, and laminating the film to current collector 202. After disposing electrode slurry 112 onto current collector 202, the slurry can be treated under vacuum, heat, or a combination thereof to provide the final active layer 201. In some embodiments, vacuum and / or heat help to remove volatile species to improve the uniformity and consistency of the final active layer 201. In some embodiments, active layer 201 is also disposed on the opposite side 203 of current collector 202.

[0147] In optional embodiments, electrode slurry 112 can be applied directly to current collector 202 or to an adhesive layer that can be adhered to current collector 202. If an adhesive layer is used, the adhesive layer can be electrically conductive.

[0148] Current collector

[0149] The current collector 202 is an electrically conductive element. The current collector 202 can include a metal (e.g., a substantially pure metal or a metal alloy, etc.). As another example, the current collector 202 can be in the form of a metal strip or a metal foil. For example, the current collector 202 can be an aluminum foil or tape, an aluminum alloy foil or tape, a copper foil or tape, or a copper alloy foil or tape. The thickness of the current collector 202 can be no more than 15 pm, no more than 10 pm, no more than 8 pm, or no more than 5 pm. In some embodiments, the thickness of the current collector 202 can be at least 3 pm. For example, the thickness of the current collector 202 can be from 3 pm to 15 pm or from 6 pm to about 8 pm. As another example, the current collector 202 is an aluminum foil or an aluminum alloy foil having a thickness of from 5 pm to 7 pm.

[0150] Electrode

[0151] Active layer

[0152] As detailed below, the cathode includes a cathode current collector on which a cathode active layer is disposed. The anode includes an anode current collector on which an anode active layer is disposed. Both the cathode current collector and the anode current collector include a metal. However, the metal is flexible and allows for deformation to accommodate swelling of the respective active layer without any change in the current being collected. Similarly, the cathode active layer and the anode active layer can undergo dimensional and / or geometric (e.g., shape) changes when subjected to interactions with electrolytes, temperature, and / or pressure changes. While the cathode and the anode can undergo dimensional and geometric changes, they help to evenly distribute the current in the energy storage device during charging / discharging. The even distribution of the current during charging and discharging reduces the formation of hot spots, which in turn reduces the formation of dendrites in the active material layers.

[0153] In an embodiment, the storage device includes high-energy electrodes (cathode and anode) in which there is no dendrite formation. In other words, the distribution of the carbonaceous material (carbonaceous particles) and the active material (active material particles) in the active layers (disposed on the cathode and anode current collectors) is uniform. There is no segregation of the respective active material (in the cathode active layer and the anode active layer) from the carbonaceous material (high aspect ratio carbon elements, activated carbon, carbon black, graphite, carbon fibers, etc. used in the respective active layers).

[0154] In an embodiment, the loading of each component in the respective active layer is uniform. The carbonaceous material and active material used in the active layer are spatially uniformly distributed over a length scale of greater than 1 pm, specifically greater than 5 pm, and more specifically greater than 50 pm. In an embodiment, the carbonaceous material and active material used in the active layer are uniformly distributed over a length scale of 1 pm to 1000 pm, and specifically 10 pm to 500 pm. In other words, over a length scale of greater than 1 pm, and specifically greater than 5 pm, a line drawn through the active layer of the anode and / or cathode has no density difference, no surface property difference, and no electrical conductivity difference. In an embodiment, the variation in density difference of a line drawn through the active layer of the anode and / or cathode is less than 10%, specifically less than 5% of the average density measured along the same line. The line can be taken in any direction.

[0155] The uniform density in the particle distribution is achieved by using particles of uniform particle size and compatible with each other, such that the phase segregation of the active material from the carbonaceous material is minimized. In an embodiment, the particle size of the carbonaceous particles and active material particles (used in the respective active layer) is less than 100 nm, specifically less than 50 nm, and more specifically less than 20 nm.

[0156] For high aspect ratio carbonaceous materials (e.g., carbon nanotubes, nanowires, nanorods, etc.), the particle size refers to the diameter of the particle, not the end-to-end distance.

[0157] Using particles (active material particles and carbonaceous particles) of particle size less than 100 nm, a uniform current distribution can be achieved in the storage device during charging and / or discharging. This reduces the formation of hot spots, and thus the formation of dendrites in the active layer.

[0158] One way to facilitate the uniform distribution of particles in the active layer is through the compatibilization of the carbonaceous particles, active material particles, and optional binder. Suitable compatibilizers are surfactants or polymeric binders.

[0159] Another method to achieve compatibilization is through the surface functionalization of the active material particles, carbonaceous particles, or both the active material particles and carbonaceous particles. A portion of the carbonaceous particles and / or active material particles can be functionalized with functional groups, such as carboxyl groups, carbonyl groups, amine groups, amide groups, thiol groups, sulfonate groups, hydroxyl groups, cyano groups, allyl groups, allene groups, norbornyl groups, acrylate groups, methacrylate groups, maleimide groups, maleic anhydride groups, and the like, or combinations thereof.

[0160] In an embodiment, the cathode and / or anode active layer comprises two layers having different compositions and different densities. The first layer, which is closest to the current collector (and either directly contacts the current collector or contacts the current collector through an adhesive layer), has a first concentration of carbonaceous material and active material, while the second layer, which is disposed on the first layer, has a second concentration of carbonaceous material relative to the active material. In an embodiment, the second concentration (of carbonaceous material relative to active material) is greater than the first concentration (of carbonaceous material relative to active material). Both layers, i.e., the first layer and the second layer, have a uniform material density throughout their volume.

[0161] Separator

[0162] The separator is disposed between the anode and the cathode, and can be electrically insulating. It is desirable for the separator to have physical compliance and be able to assume different shapes depending on the shape of the anode and cathode active layers. In other words, the relative surfaces of the separator are able to contact the surfaces of the anode and cathode active layers regardless of how the shape of the anode or cathode changes.

[0163] The shape of the anode and cathode active layers changes due to the interaction of the electrolyte with the anode and cathode active materials as the electrolyte is added to the storage device. The shape can also change due to changes in temperature during operation of the storage device. It is therefore desirable for the separator to undergo a corresponding change in shape, or alternatively, to accommodate such a change in shape while continuing to contact the anode and cathode active layers. In other words, there is simultaneous continuous contact between the anode surface and the separator and between the cathode and the separator regardless of the operating conditions of the storage device.

[0164] In exemplary embodiments, the simultaneous continuous contact between the separator and the anode surface and between the separator and the cathode surface is achieved by manufacturing the separator from a material that is compliant and can easily change shape. The compliant material used in the separator can expand or contract to maintain continuous contact with the entire surface of the anode and cathode active layers while not allowing the electrolyte to leak from the anode region of the storage device to the cathode region of the storage device. Despite the flexibility of the separator, electrical particles (ions or electrons) should not be transmitted through the separator.

[0165] A suitable example of a compliant material for the separator is an electrically insulating elastomer. Suitable elastomers are polybutadiene, polyisoprene, styrene-butadiene rubber, poly(styrene)-block-poly(butadiene), poly(acrylonitrile)-block-poly(styrene)-block-poly(butadiene) (ABS), polychloroprene, epichlorohydrin rubber, polyacrylic rubber, silicone elastomers (polysiloxanes), fluorosilicone elastomers, fluoroelastomers, perfluoroelastomers, polyether block amides (PEBA), chlorosulfonated polyethylene, ethylene propylene rubber (EPR), ethylene-vinyl acetate elastomers, and the like, or combinations thereof.

[0166] In one embodiment, the separator can contain a rigid central region (substrate) provided with a compliant layer on its opposite surfaces that can accommodate the geometric variations of the anode and cathode active layers, respectively. The rigid central portion can comprise a ceramic or metal completely coated with a compliant layer. The compliant layer is one of the elastomers listed above.

[0167] Ceramic substrates include metal oxides, metal carbides, metal nitrides, metal borides, metal silicides, metal oxycarbides, metal oxynitrides, metal boronitrides, metal carbonitrides, metal borocarbides, and the like or combinations thereof. Examples of ceramics that can be used as substrates include silicon dioxide, aluminum oxide, titanium dioxide, zirconium dioxide, indium tin oxide, antimony tin oxide, cerium oxide, cadmium oxide, titanium nitride, silicon nitride, aluminum nitride, titanium carbide, silicon carbide, titanium niobium carbide, stoichiometric borosilicide compounds (SiBn, where n = 14, 15, 40, and the like) (e.g., silicon triboride SiB3, silicon tetraboride SiB4, silicon hexaboride SiB6, and the like), and the like or combinations thereof.

[0168] Examples of metal oxides include quartz, silicon dioxide, aluminum oxide, titanium dioxide, zirconium dioxide, cerium dioxide, and the like or combinations thereof.

[0169] Electrolyte

[0170] The electrolyte used in the storage device can be a gaseous electrolyte, a liquid electrolyte, or a solid electrolyte. In one embodiment, the electrolyte is a solid electrolyte that includes a polymeric material in which an ionic electrolyte is embedded.

[0171] The polymeric material used in the electrolyte is an organic polymer selected from a variety of thermoplastic polymers, a blend of thermoplastic polymers, a thermoset polymer, or a blend of a thermoplastic polymer and a thermoset polymer. The organic polymer can also be a blend of polymers, a copolymer, a terpolymer, or a combination including at least one of the foregoing organic polymers. The organic polymer can also be an oligomer, a homopolymer, a copolymer, a block copolymer, an alternating block copolymer, a random polymer, a random copolymer, a random block copolymer, a graft copolymer, a star block copolymer, a dendrimer, a polyelectrolyte (a polymer having some repeating groups containing an electrolyte), a polyampholyte (a polyelectrolyte having both cationic and anionic repeating groups), an ionomer, and the like or a combination including at least one of the foregoing organic polymers. The organic polymer has a number average molecular weight greater than 10,000 g / mol, specifically greater than 20,000 g / mol, and more specifically greater than 50,000 g / mol. In some embodiments, the average molecular weight of the organic polymer is up to 200,000 g / mol.

[0172] Examples of the organic polymer include polyacetals, polyacrylic acids, polycarbonates, polyalkyd resins, polystyrenes, polyolefins, polyesters, polyamides, polyaramides, polyamide-imides, polyarylates, polyurethanes, epoxy resins, phenolic compounds, silicone resins, polyarylsulfones, polyethersulfones, polyphenylene sulfides, polysulfones, polyimides, polyetherimides, polytetrafluoroethylene, polyether ketones, polyether ether ketones, polyether ketone ketones, polybenzoxazoles, polyoxadiazoles, polybenzothiazines phenothiazines, polybenzothiazoles, polypryrozoloquinoxalines, polyquinoxalines, polybenzimidazoles, polyoxindoles, polyoxoisoindolines, polydioxoisoindolines, polytriazines, polypridazines, polypriazines, polypyridines, polypiperidines, polytriazoles, polyprazoles, polycarboranes, polyoxabicylononanes, polydibenzofurans, polytetrachlorophthalides, polyacetals, polyanhydrides, polyvinyl ethers, polyvinyl sulfides, polyvinyl alcohols, polyvinyl ketones, polyvinyl halides, polyvinyl nitriles, polyvinyl esters, polysulfonates, polysulfides, polythioesters, polysulfones, polysulfonamides, polyureas, polyphosphazenes, polysilazanes, polypropylenes, polyethylenes, polyethylene terephthalates, polyvinylidene fluorides, polysiloxanes, or combinations comprising at least one of the foregoing organic polymers.

[0173] In an embodiment, the electrolyte is a swollen solid-state electrolyte comprising one of the foregoing polymers and comprising a solvent and an ionic liquid. The solvent and the ionic liquid penetrate into the solid polymer, causing it to swell and form a gelled solid-state electrolyte, which can penetrate into the active layers (of the anode and the cathode) and which can also contact the separator.

[0174] In an embodiment, the electrolyte is very pure and free of impurities, wherein the impurities are present in a concentration of less than 900 parts per million.

[0175] In an embodiment, the solid-state electrolyte is a swollen solid-state electrolyte comprising a polymer solid, an ionic liquid, and a solvent. The solvent can be present in an amount of 2 wt% to 15 wt%, in particular 3 wt% to 10 wt%, based on the total weight of the solid-state electrolyte.

[0176] In an embodiment, there is no impurity in the storage device and in particular in the electrolyte that can reside between the active layer surface and the separator or between the solid-state electrolyte surface and the separator.

[0177] Preparation of the electrode

[0178] The electrode 200 can be produced by first preparing an electrode slurry 112 of the conductive element 102, the active material 107, and the binder 110. In some embodiments, the electrode slurry 112 can include the plasticizer 105. The method for manufacturing the electrode 200 is a solvent-free and fluorine-free method. The method for manufacturing the anode can also be used to manufacture the cathode. The electrode slurry 112 can be coated directly on the current collector or applied to the current collector through an intermediate adhesive layer.

[0179] The electrode prepared by this solvent-free method can eliminate or reduce material agglomeration and electrode cracking due to solvent removal during manufacturing. The electrode prepared by this solvent-free method can provide uniform distribution of the conductive element 102, the active material 107, and / or the binder 110 within the electrode.

[0180] The electrode slurry 112 can be prepared in one step. Alternatively, the electrode slurry 112 can be prepared according to a multi-step process as shown in the flowchart of the method 100 example described below. Figure 1

[0181] In an optional step, the binder 110 or an additional binder can be applied as a surface treatment, which can be formed completely or partially on the conductive material 102 (e.g., high aspect ratio carbon elements) in the initial slurry. In some embodiments, the surface treatment at this stage can be self-assembled.

[0182] The resulting surface treatment can include functional groups or other features that can facilitate adhesion between the high aspect ratio carbon elements and the active material particles as described in the additional steps below. For example, functional groups on the binder can provide the surface treatment.

[0183] The active material 107 can be added directly to the initial slurry. Alternatively, the active material 107 can first be dispersed in the plasticizer 105 to form an active material slurry. This active material slurry can then be combined with the initial slurry to form the final electrode slurry 112.

[0184] The plasticizer 105 can be added to the mixture of the binder 110, the conductive material 102, and the active material 107 in a total amount of 1 wt% to 20 wt%, 5 wt% to 15 wt% of the total weight of the materials used to form the active layer 201.

[0185] ​The active layer 201 is formed from the final electrode paste 112. In some embodiments, the electrode paste 112 can be cast directly onto the current collector 202 (or optional adhesive layer disposed on the current collector 202) and dried to remove volatile materials. As an example, the casting can be by application of at least one of heat and vacuum until substantially all of the volatile materials have been removed, thereby forming the active layer 201. It can be desirable to protect various portions of the underlayer. For example, where the electrode 200 is intended for single-sided operation, it can be desirable to protect the bottom surface 203 of the current collector. Protection can include, for example, protection from the electrode paste 112 by masking certain areas.

[0186] In another example, the electrode paste 112 can be at least partially dried elsewhere before being transferred to the current collector 202 (or optional adhesive layer disposed on the current collector 202) using any suitable technique (e.g., roll-to-roll layer application) to form the active layer 201. As another example, the electrode paste 112 can be placed onto an intermediate material having a suitable surface and dried to form a layer (e.g., the active layer 201). While any material having a suitable surface can be used as the intermediate material, exemplary intermediate materials include polytetrafluoroethylene (PTFE) because of its properties that facilitate subsequent removal from the surface. The layer can be formed in a press to provide a layer exhibiting a desired thickness, area, and density.

[0187] In yet another example, the electrode paste 112 can be formed into a sheet and coated onto the current collector 202 (or optional adhesive layer disposed on the current collector 202). For example, the electrode paste 112 can be applied through a slot die to control the thickness of the layer applied. As another example, the electrode paste 112 can be applied and then leveled to a desired thickness, e.g., using a doctor blade. Various other techniques can be used to apply the electrode paste 112. For example, coating techniques can include, but are not limited to: comma coating; comma reverse coating; doctor blade coating; slot die coating; direct gravure coating; air doctor coating (air knife); chamber doctor coating; offset gravure coating; single roll contact coating; reverse contact coating with small diameter gravure roll; rod coating; three roll reverse coating (top feed); three roll reverse coating (fountain die); reverse roll coating; and the like.

[0188] If desired, the active layer 201 formed from the electrode slurry 112 can be compressed (e.g., using a calendering apparatus) before or after being applied to make the electrode 200. The electrode slurry 112 can be partially or fully dried (e.g., by applying heat, vacuum, or a combination thereof) before or during the compression process. For example, in some embodiments, the active layer 201 can be compressed to a final thickness (e.g., in a direction perpendicular to the current collector layer 202) that is less than 90%, 80%, 70%, 50%, 40%, 30%, 20%, 10%, or less of its pre-compression thickness.

[0189] When partially dried layers are formed during coating or compression, the layers can be subsequently fully dried (e.g., by applying heat, vacuum, or a combination thereof). In some embodiments, substantially all volatile matter is removed from the active layer 201.

[0190] The active layer 201 can be compressed, for example, to break some of the constituent high aspect ratio carbon elements or other carbonaceous materials to increase the surface area of the respective layer. Such compression treatment can increase one or more of the interlayer adhesion, the in-layer ion transport rate, and the surface area of the layer. In various embodiments, the compression can be applied before or after the respective layer is applied to or formed on the electrode 200.

[0191] In cases where calendering is used to compress the active layer 201, the nip spacing of the calendering apparatus can be set to equal less than 90%, 80%, 70%, 50%, 40%, 30%, 20%, 10%, or less of the pre-compression thickness of the layer (e.g., set to about 33% of the pre-compression thickness of the layer). The compression rollers can be configured to provide a suitable pressure, for example, greater than 1 ton / cm of roller length, greater than 1.5 tons / cm of roller length, greater than 2.0 tons / cm of roller length, greater than 2.5 tons / cm of roller length, or greater. The density of the active layer after compression can be 1 g / cm 3 to 10 g / cm 3 or any sub-range thereof such as 2.0 g / cm 3 to 4.0 g / cm 3 . Notably, the density of the cathode active layer can be 2 g / cm 3 to 4 g / cm 3 . The density of the anode active layer can be 1.0 g / cm 3 to 1.8 g / cm 3 . The calendering process can be performed at a temperature of 20 °C to 140 °C or any sub-range thereof. In some embodiments, the active layer 201 can be pre-heated prior to calendering, for example, at a temperature of 20 °C to 100 °C or any sub-range thereof.

[0192] The electrode preparation process can include any of the following features (alone or in any suitable combination):

[0193] The scaffold or matrix of conductive material 102 and binder 110 can hold active material 107 particles together to form a cohesive layer that strongly attaches to the current collector 202. Such active material structures can be produced during slurry preparation and subsequently during roll-to-roll (“R2R”) coating and drying processes. One of the main advantages of this technology is its scalability and “embedded” nature, as various embodiments are compatible with conventional electrode manufacturing processes.

[0194] The matrix can be formed during slurry preparation using the technology described herein: high aspect ratio carbon material is properly dispersed and chemically functionalized as needed. The chemical functionalization is intended to form organized self-assembly structures with the surface of active material particles, such as NMC particles (detailed below) for cathodes or silicon (“Si”) or silicon oxide (“SiOx”) particles in the case of anodes. Electrostatic interactions promote self-organization structures in the slurry, and after the drying process, the binding between the carbon matrix with active material particles thus formed and the current collector surface is promoted by surface treatment (e.g., functional groups on the matrix) and strong entanglement of the active material in the carbon matrix.

[0195] The mechanical properties of the electrode can be varied according to the application and mass loading requirements by adjusting the surface functionalization with the entanglement effect.

[0196] After coating and drying, the electrode can undergo a calendering step to control the density and porosity of the active material. In NMC cathode electrodes, densities of > 3.5 g / cm 3 or higher and porosities of 20% or higher can be achieved. The porosity can be optimized according to the mass loading and requirements of the lithium-ion battery cell. For silicon oxide or silicon-based anodes, the porosity can be controlled to accommodate the expansion of the active material during the lithiation process.

[0197] The teachings herein can provide a reduction of up to 30% of $ / kWh. By using a solventless process, the electrode production volume can be higher, and more importantly, the energy consumption for long drying periods can be significantly reduced.

[0198] The teachings herein provide active layers with 3D matrix that can increase electrode conductivity by a factor of 10 to 100 times compared to electrodes using conventional binders such as PVDF, which enables fast charging at certain battery capacity. With this technology, up to 150 pm thick electrode coating per side of the current collector 202 can be achieved. The plasticizer used in the slurry preparation method 100, in combination with the strong 3D carbon matrix, is designed to enable thick wet coating without cracking during the drying step. The thick cathode and high capacity anode enable a significant jump in energy density, reaching 400 Wh / kg or higher.

[0199] In some embodiments, the active layer 201 can be prepared by applying multiple layers of the electrode slurry 112 on the current collector 202. In an example, a first electrode slurry 112 is applied to the current collector 202 to form a first layer. A second electrode slurry 112 is applied to the first layer to form a second layer. In some embodiments, the electrode slurry 112 used to form the first layer is different from the electrode slurry 112 used to form the second layer.

[0200] Energy storage device

[0201] Once the electrode 100 is prepared, the electrode 100 can be used to assemble an energy storage device. Assembly of the energy storage device can follow conventional steps for assembling electrodes with separators and placing within a housing such as a can or pouch, and can also include additional steps for electrolyte addition and sealing of the housing.

[0202] One example embodiment includes a battery cell of a cathode and an anode, where the cathode and the anode each include a current collector and an active layer. The battery cell has a fluorine content of less than 900 parts per million. The anode active layer, the cathode active layer, or both the anode active layer and the cathode active layer can include a high aspect ratio carbon element.

[0203] The energy storage device can include a housing. The housing can have two terminals disposed on an exterior thereof. The terminals provide internal electrical connections to the storage battery cell contained within the housing, and external electrical connections to external devices such as a load device or a charging device. The energy storage devices disclosed herein can be a battery, a capacitor, a supercapacitor, etc.

[0204] In an embodiment, the energy storage device can have an initial specific capacity of about 1500 milliampere hours per gram (mAh / g) to about 1600 mAh / g, specifically about 1400 mAh / g to about 1500 mAh / g, and an initial coulombic efficiency of about 90% to about 94%; specifically about 1350 mAh / g to about 1400 mAh / g, and an initial coulombic efficiency of about 87% to about 89%.

[0205] The present disclosure can alternatively comprise, consist of, or consist essentially of, any appropriate components disclosed herein. Additionally or alternatively, the present disclosure can be formulated so as to be devoid of, or substantially free of, any components, materials, ingredients, adjuvants or species used in the prior art compositions which might be inconsistent with the functions and / or objectives of the present disclosure.

[0206] All cited patents, patent applications, and other references are incorporated by reference in their entirety. However, if a term in the present application contradicts or conflicts with a term in the incorporated reference, the term from the present application prevails.

Claims

1. A solvent-free method for preparing electrode paste, the method comprising: Carbonaceous conductive materials, plasticizers, active materials, and polymer binders are mixed to form an electrode paste; The fluorine content of the electrode paste is less than 900 parts per million.

2. The method according to claim 1, wherein the solid content of the electrode slurry is 80% to 100% by weight of the total weight of the electrode slurry.

3. The method of claim 1, wherein the dispersant is mixed with the conductive material, the plasticizer, and the active material.

4. The method of claim 1, wherein the mixing is carried out using a twin-screw extruder.

5. The method according to claim 1, wherein the active material is an anodic active material, a cathodic active material, or a combination thereof.

6. A battery cell, the battery cell comprising: Cathode electrode and anode electrode; The cathode comprises a cathode current collector and a cathode active layer, wherein the cathode active layer comprises a cathode active material, including LFP, LiCoO2, LiNiO2, LiNiMnCoO2, LiNiO2, LiMn2O4, LiFePO4, and LiNi x Mn y Co 1-x-y O2, NCMA or one or more of these or a combination thereof, wherein the value of x is 0.7 to 0.85 and wherein y is greater than 0.1; and wherein the cathode active layer is in contact with the cathode current collector; The anode comprises an anode current collector and an anode active layer; wherein the anode active layer comprises an anode active material, the anode active material comprising materials reacting with Li x Si y O z The graphite is a mixture, wherein x is 1 to 15, y is 1 to 4 and z is 1 to 9; the anode active layer is in contact with the anode current collector; Both the anode active layer and the cathode active layer contain carbon elements with a high aspect ratio; The cathode, the anode, or both are prepared by a solvent-free method, and the fluorine content of the battery electrodes is less than 900 parts per million.

7. An energy storage device, the energy storage device comprising: case; A diaphragm, a cathode, and an anode are disposed within the housing; wherein the anode and the cathode are disposed on opposite sides of the diaphragm; and The cathode and the anode each include a current collector, and an active layer is disposed on the current collector; wherein the active layer includes a carbonaceous conductive material, a plasticizer, an active material, and a binder; The cathode, the anode, or both are prepared by a solvent-free method; and the fluorine content of the active layer is less than 900 parts per million.

8. The energy storage device according to claim 7, wherein the active layer comprises an anode active layer and a cathode active layer; and wherein the cathode active layer, the anode active layer, or the cathode active layer and the anode active layer are capable of dimensional and / or geometrical changes during operation of the energy storage device.

9. The energy storage device according to claim 7, wherein the current collector is capable of deforming in response to changes in the size or geometry of the active layer.

10. The energy storage device of claim 7, wherein the diaphragm is deformable to adapt to changes in the size or geometry of the active layer.

11. The energy storage device of claim 7, wherein the active layer comprises an anode active layer and a cathode active layer; wherein the anode active layer or the cathode active layer comprises a first layer and a second layer, wherein the first layer is in contact with the current collector and wherein the second layer is in contact with the first layer; wherein the second layer has a lower concentration of active material than the first layer.

12. The energy storage device of claim 11, wherein the second layer has a higher concentration of carbonaceous material than the first layer.

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