Modified binder for lithium ion electrode plate, lithium ion electrode plate as well as preparation method and application of lithium ion electrode plate

Abstract

The invention discloses a modified binder for a lithium ion battery pole piece, the lithium ion battery pole piece as well as a preparation method and application of the lithium ion battery pole piece, and relates to the field of battery materials. The modified binder comprises an acrylated or methacrylated polymer binder, the polymer binder contains hydroxyl and / or carboxyl, and meanwhile, the lithium ion electrode plate is subjected to pre-lithiation treatment by adopting a lithium naphthalene reagent. The modified binder in the electrode slurry is subjected to acryloylation treatment in advance, the electrode plate is subjected to pre-lithiation treatment by adopting the lithium naphthalene reagent, in-situ crosslinking of the modified binder caused by anionic polymerization is realized by utilizing the lithium naphthalene reagent, and meanwhile, the requirements of high mechanical strength and uniform dispersity of the binder and efficient pre-lithiation of the electrode are met; the first irreversible capacity loss of the battery is remarkably reduced, the coulombic efficiency and the cycling stability of the battery are improved, additional crosslinking steps or complex reaction conditions are not needed, and the preparation cost and the process difficulty are reduced.

Description

Technical Field

[0001] This invention relates to the field of battery materials, and in particular to a modified binder for lithium-ion electrode sheets, lithium-ion electrode sheets, their preparation methods, and applications. Background Technology

[0002] Lithium-ion batteries are widely used in consumer electronics, energy storage systems, and electric vehicles due to their high energy density and long cycle life. However, as the demand for batteries with higher capacity and longer lifespan continues to increase, the performance limitations of traditional electrode materials and binders are becoming increasingly apparent.

[0003] Binders, as a crucial component of electrodes, are responsible for fixing active material particles onto the current collector while providing conductivity and structural integrity. Commonly used binders include polyvinylidene fluoride (PVDF), polyacrylic acid (PAA), and bio-based materials such as sodium alginate. However, existing binders exhibit the following drawbacks: 1) Insufficient mechanical strength: Existing binders are prone to cracking or peeling during electrode expansion and contraction, leading to decreased cycle performance; 2) Limited processing technology: During slurry preparation, some binders are difficult to dissolve or disperse uniformly, affecting the consistency of electrode performance; 3) Limited functionality: Traditional binders only provide physical bonding and conductive channels, failing to further improve the overall mechanical properties and electrochemical stability of the electrode.

[0004] In recent years, researchers have attempted to enhance binders by introducing in-situ crosslinking technology. However, these methods typically require additional crosslinking steps or special reaction conditions during preparation, increasing the complexity of the preparation process and production costs. Furthermore, the crosslinked binder is difficult to dissolve or disperse, which is detrimental to the uniform preparation of electrode slurries and limits the control over the electrode structure. Summary of the Invention

[0005] This invention provides a modified binder for lithium-ion electrode sheets, lithium-ion electrode sheets, their preparation methods, and applications. By utilizing the dual functions of lithium naphthalene reagent, in-situ crosslinking of the binder is achieved during the electrode pre-lithiation process, thereby simultaneously satisfying the requirements of high mechanical strength, uniform dispersion, and efficient electrode pre-lithiation of the binder, significantly improving the coulombic efficiency, specific capacity, and cycle stability of the battery.

[0006] To address the aforementioned technical problems, one objective of this invention is to provide a modified binder for lithium-ion electrode sheets, comprising an acryloylated or methacrylated polymer binder, wherein the polymer binder contains hydroxyl and / or carboxyl groups.

[0007] Acrylation, or methacrylation, is a commonly used method in the biomedical field for modifying polymers. Acrylation allows polymers with carboxyl or hydroxyl groups to acquire a certain number of carbon-carbon double bond functional groups on their side groups. This application introduces a certain number of carbon-carbon double bond functional groups into the molecular structure of a polymer binder, which helps to initiate anionic polymerization and in-situ crosslinking during the subsequent pre-lithiation process of electrode preparation. This improves the mechanical strength of the binder and prevents cracking or peeling during electrode expansion and contraction, thereby improving the specific capacity, coulombic efficiency, and cycle performance of the prepared battery.

[0008] As a preferred embodiment, the polymer binder is at least one of polyacrylic acid, polyvinyl alcohol, sodium alginate, and carboxymethyl cellulose.

[0009] To address the aforementioned technical problems, a second objective of this invention is to provide a method for preparing a modified binder for lithium-ion electrode sheets, comprising the following steps:

[0010] (1) Dissolve the polymer binder in water, stir evenly, and then add acid to adjust the pH to 3-4;

[0011] (2) Glycidyl acrylate was slowly added to the solution, and the mixture was heated and stirred. Then, organic solvent was slowly added and stirred to promote precipitation of the product. The modified binder was collected by centrifugation.

[0012] As a preferred embodiment, in step (1), the mass ratio of the polymer binder to water is 1:(10-30).

[0013] As a preferred embodiment, in step (1), the mass ratio of the polymer binder to glycidyl acrylate is (2-5):1.

[0014] As a preferred embodiment, in step (1), the acid is hydrochloric acid, and the concentration of the hydrochloric acid is 0.05-1 mol / L.

[0015] As a preferred embodiment, in step (2), the heating temperature is 40-60℃ and the reaction time is 12-48h.

[0016] As a preferred embodiment, in step (2), the volume ratio of the organic solvent to water is (1-3):1.

[0017] As a preferred embodiment, in step (2), the organic solvent is at least one of acetone, acetonitrile, methanol, and ethanol.

[0018] To address the aforementioned technical problems, a third objective of this invention is to provide a lithium-ion electrode sheet, comprising a lithium-ion electrode material modified binder.

[0019] As a preferred embodiment, the active material, modified binder, and conductive agent are present in a mass ratio of (2-5):(0.5-2):(0.5-2).

[0020] As a preferred embodiment, the active material is at least one of carbon-based compounds, silicon-based compounds, and transition metal nitrides.

[0021] As a preferred embodiment, the conductive agent is at least one of carbon nanotubes, conductive carbon black, conductive graphite, acetylene black, and graphene.

[0022] To address the aforementioned technical problems, the fourth objective of this invention is to provide a method for preparing a lithium-ion electrode sheet, comprising the following steps:

[0023] (1) Grind and mix the active material, conductive agent and modified binder evenly, add water to the mixture and stir evenly to obtain a slurry with a solid content of 10wt%-15wt%.

[0024] (2) The slurry is uniformly coated on the current collector substrate and dried to obtain an electrode sheet;

[0025] (3) After cutting the electrode sheet, it is pre-lithiated in lithium naphthalene reagent to obtain lithium-ion electrode sheet.

[0026] In this application, the modified binder in the electrode slurry undergoes pre-acrylylation treatment, introducing a certain number of carbon-carbon double bond functional groups into the polymer binder's molecular structure. The modified binder in the electrode slurry exhibits a linear structure, which contributes to the slurry's uniformity and dispersibility, avoiding the processing difficulties encountered with traditional crosslinking binders. The electrode sheet undergoes pre-lithiation treatment using lithium naphthalene reagent. Lithium naphthalene can partially or completely pre-lithiate electrode materials such as silicon and sulfur, significantly reducing the battery's initial irreversible capacity loss and significantly improving the battery's first-cycle coulombic efficiency. Simultaneously, during the electrode sheet pre-lithiation process, the lithium naphthalene reagent enables in-situ crosslinking of the modified binder due to anionic polymerization, significantly improving the binder's structural stability during electrode expansion and contraction, and enhancing the battery's cycle performance. Utilizing the dual function of the lithium naphthalene reagent, in-situ crosslinking of the binder is achieved during electrode pre-lithiation, simultaneously satisfying the requirements of high mechanical strength, uniform dispersion, and efficient electrode pre-lithiation. The in-situ crosslinking method occurs during the electrode pre-lithiation step, eliminating the need for additional crosslinking steps or complex reaction conditions, thus reducing preparation costs and process difficulty.

[0027] As a preferred embodiment, the preparation method of the lithium naphthalene reagent includes the following steps: dissolving metallic lithium and naphthalene in a molar ratio of (1-2):(1-2) in ethylene glycol dimethyl ether to obtain the lithium naphthalene reagent.

[0028] As a preferred embodiment, the concentration of the lithium naphthalene reagent is 0.3-0.8 mol / L.

[0029] As a preferred embodiment, the current collector is copper foil.

[0030] As a preferred embodiment, in step (3), the drying temperature is 40-60℃ and the drying time is 6-24h.

[0031] To address the aforementioned technical problems, the fifth objective of this invention is to provide an application of lithium-ion electrode sheets in the preparation of lithium-ion batteries.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1. In this application, the modified binder in the electrode slurry is pre-acrylated, and the electrode sheet is pre-lithiated using lithium naphthalene reagent. Lithium naphthalene can partially or completely pre-lithiate electrode materials such as silicon and sulfur, significantly reducing the first irreversible capacity loss of the battery and significantly improving the first-cycle coulombic efficiency of the battery. At the same time, the lithium naphthalene reagent is used to achieve in-situ crosslinking of the modified binder caused by anionic polymerization, which significantly improves the structural stability of the binder during the electrode expansion and contraction process, and improves the specific capacity, coulombic efficiency and cycle stability of the battery.

[0034] 2. The modified binder in the electrode slurry of this application has a linear structure, which helps the slurry uniformity and dispersion, avoiding the problem of traditional crosslinking binders being difficult to process. During the pre-lithiation of the electrode sheet, the dual function of lithium naphthalene reagent is utilized to achieve in-situ crosslinking of the binder during the electrode pre-lithiation process. This can simultaneously meet the requirements of high mechanical strength, uniform dispersion and efficient pre-lithiation of the electrode. The in-situ crosslinking method occurs in the electrode pre-lithiation step, without the need for additional crosslinking steps or complex reaction conditions, thus reducing the preparation cost and process difficulty. Attached Figure Description

[0035] Figure 1 This is a schematic diagram illustrating the reaction mechanism of the lithium-ion electrode sheet during the pre-lithiation process in an embodiment of the present invention.

[0036] Figure 2 : This is a statistical chart showing the specific capacity, coulombic efficiency, and capacity retention of the half-cell assembled with lithium-ion electrode sheets in Embodiment 1 of the present invention as a function of the number of charge-discharge cycles.

[0037] Figure 3 : This is a statistical curve of the first-cycle voltage-specific capacity of the half-cell assembled with lithium-ion electrode sheets in Embodiment 1 of the present invention;

[0038] Figure 4 : This is a statistical chart showing the specific capacity, coulombic efficiency, and capacity retention of the half-cell assembled with lithium-ion electrode sheets in Comparative Example 1 of this invention as a function of the number of charge-discharge cycles.

[0039] Figure 5 : This is a statistical curve of the first-cycle voltage-specific capacity of the half-cell assembled with lithium-ion electrode sheets in Comparative Example 1 of the present invention.

[0040] Figure 6 : This is a statistical chart showing the specific capacity, coulombic efficiency, and capacity retention of the half-cell assembled with lithium-ion electrode sheets in Comparative Example 2 of this invention as a function of the number of charge-discharge cycles.

[0041] Figure 7 : This is a statistical curve of the first-cycle voltage-specific capacity of the half-cell assembled with lithium-ion electrode sheets in Comparative Example 2 of this invention. Detailed Implementation

[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0044] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0045] To further illustrate the present invention, the following detailed description is provided in conjunction with embodiments, but these should not be construed as limiting the scope of protection of the present invention. Unless otherwise specified, all raw materials used in the following embodiments and comparative examples are commercially available, and the same raw materials were used in parallel experiments.

[0046] Preparation Example 1

[0047] A method for preparing a modified binder for lithium-ion electrode materials includes the following steps:

[0048] (1) Dissolve 5g of polyacrylic acid (PAA) in 100mL of deionized water. Stir with a magnetic stirrer at room temperature until completely dissolved. Add 0.1mol / L hydrochloric acid dropwise to the solution and adjust the pH to about 3.5.

[0049] (2) Slowly add 1.35 mL of glycidyl acrylate (GMA) to the solution and stir for 24 h under temperature control at 50 °C. Keep the solution stirred evenly during the reaction. After the reaction is complete, slowly add 200 mL of ethanol and stir to promote the precipitation of white crude product. Centrifuge to collect the precipitate and obtain the modified binder.

[0050] Preparation Example 2

[0051] A method for preparing a modified binder for lithium-ion electrode materials includes the following steps:

[0052] (1) Dissolve 5g of polyvinyl alcohol in 100mL of deionized water and stir with a magnetic stirrer at room temperature until completely dissolved. Add 0.1mol / L hydrochloric acid dropwise to the solution and adjust the pH to about 3.5.

[0053] (2) Slowly add 1.35 mL of glycidyl acrylate (GMA) to the solution and stir for 24 h under temperature control at 50 °C. Keep the solution stirred evenly during the reaction. After the reaction is complete, slowly add 200 mL of ethanol and stir to promote the precipitation of white crude product. Centrifuge to collect the precipitate and obtain the modified binder.

[0054] Preparation Example 3

[0055] A method for preparing a modified binder for lithium-ion electrode materials includes the following steps:

[0056] (1) Dissolve 5g of sodium alginate in 100mL of deionized water and stir with a magnetic stirrer at room temperature until completely dissolved. Add 0.1mol / L hydrochloric acid dropwise to the solution and adjust the pH to about 3.5.

[0057] (2) Slowly add 1.35 mL of glycidyl acrylate (GMA) to the solution and stir for 24 h under temperature control at 50 °C. Keep the solution stirred evenly during the reaction. After the reaction is complete, slowly add 200 mL of ethanol and stir to promote the precipitation of white crude product. Centrifuge to collect the precipitate and obtain the modified binder.

[0058] Preparation Example 4

[0059] A method for preparing a lithium naphthalene reagent (Li-Naph) includes the following steps:

[0060] (1) Dissolve 10 mmol of metallic lithium and 10 mmol of naphthalene in 10 mL of anhydrous ethylene glycol dimethyl ether in a glove box to obtain a 1 mol / L mother liquor;

[0061] (2) When using, dilute 1 mol L-1 of the mother liquor with anhydrous ethylene glycol dimethyl ether to obtain 0.5 mol / L lithium naphthalene reagent.

[0062] Example 1

[0063] A method for preparing a lithium-ion electrode sheet includes the following steps:

[0064] (1) Place 3.5g of nano-silicon and 1g of carbon nanotubes (CNTs) into a mortar and grind and mix them evenly. Add 1g of the binder from Preparation Example 1 and continue grinding and mixing to make it evenly dispersed in silicon and carbon nanotubes. Add deionized water to the mixture to make the solid content of the electrode slurry 15wt%. Use a magnetic stirrer to stir to ensure that the slurry is uniform and free of bubbles. Continue stirring until it is completely dispersed to obtain a slurry with a uniform viscous state.

[0065] (2) The above slurry is evenly coated on the copper foil substrate. The coating thickness is controlled by a coating machine to ensure the uniformity of the electrode film. The coated electrode film is placed in a vacuum drying oven and dried at 50°C for 12 hours to remove moisture and solvent, so as to obtain a dried electrode sheet.

[0066] (3) The dried electrode sheet was cut into a circular piece with a diameter of 14 mm and immersed in the lithium naphthalene reagent of Preparation Example 4 to pre-lithiate the electrode, thus obtaining a lithium-ion negative electrode sheet.

[0067] Example 2

[0068] A method for preparing a lithium-ion electrode sheet, wherein the reagents, equipment and process parameters used in each step are the same as those in Example 1, except that in step (1), the binder of Preparation Example 1 is replaced by an equal amount of the binder of Preparation Example 2.

[0069] Example 3

[0070] A method for preparing a lithium-ion electrode sheet, wherein the reagents, equipment and process parameters used in each step are the same as those in Example 1, except that in step (1), the binder of Preparation Example 1 is replaced by an equal amount of the binder of Preparation Example 3.

[0071] Comparative Example 1

[0072] A method for preparing a lithium-ion electrode sheet includes the following steps:

[0073] (1) Place 3.5g of nano-silicon and 1g of carbon nanotubes (CNTs) into a mortar and grind and mix them evenly. Add 1g of the binder prepared in Preparation Example 1 and continue grinding and mixing to make it evenly dispersed in silicon and carbon nanotubes. Add deionized water to the mixture and stir it with a magnetic stirrer to ensure that the slurry is uniform and free of bubbles. Continue stirring until it is completely dispersed to obtain a slurry with a uniform viscous state.

[0074] (2) The above slurry is uniformly coated on the copper foil substrate. The coating thickness is controlled by a coating machine to ensure the uniformity of the electrode film. The coated electrode film is placed in a vacuum drying oven and dried at 50°C for 12 hours to remove moisture and solvent. The dried electrode sheet is cut into a circular piece with a diameter of 14 mm to obtain a lithium-ion negative electrode sheet.

[0075] Comparative Example 2

[0076] A method for preparing a lithium-ion electrode sheet, wherein the reagents, equipment and process parameters used in each step are the same as those in Example 1, except that in step (1), the binder in Example 1 is replaced by an equal amount of polyacrylic acid.

[0077] Comparative Example 3

[0078] A method for preparing a lithium-ion electrode sheet, wherein the reagents, equipment and process parameters used in each step are the same as those in Comparative Example 1, except that in step (1), the binder in Preparation Example 1 is replaced by an equal amount of polyacrylic acid.

[0079] Performance testing

[0080] The electrode sheets prepared in the examples and comparative examples were assembled into half-cells with lithium sheets and polypropylene separators. An electrolyte was injected, comprising 1 mol / L LiPF6, 10 wt% fluoroethylene carbonate (FEC), and the balance solvent, which consisted of ethylene carbonate (EC) and dimethyl carbonate (DMC) in a 1:1 mass ratio. After assembly, the half-cells were subjected to electrochemical performance testing using a current density of 10 A / g and a voltage window of 0.01 V–2 V. The specific capacity after 100 cycles, capacity retention after 100 cycles, and first-cycle coulombic efficiency were evaluated through charge-discharge tests. The test results are shown below. Figure 2-7 As shown in Table 1.

[0081] Table 1 - Electrochemical performance test results of the half-cells assembled in the embodiments and comparative examples of this application.

[0082]

[0083]

[0084] In the electrode pre-lithiation process of Examples 1-3 of this application, lithium naphthalene can partially or completely pre-lithiate electrode materials such as silicon and sulfur, significantly reducing the initial irreversible capacity loss of the battery and significantly improving the first-cycle coulombic efficiency. Furthermore, the binder is acrylated using glycidyl acrylate, giving the binder polymer with carboxyl or hydroxyl groups a certain number of carbon-carbon double bond functional groups on its side groups. This allows for better pre-lithiation of the electrode sheet in subsequent processes. Figure 1 As shown, lithium naphthalene reagent can efficiently initiate anionic polymerization of vinyl monomers and perform in-situ crosslinking. This in-situ crosslinking method occurs during the pre-lithiation step of the electrode sheet without additional steps, allowing the binder to maintain a linear structure in the electrode slurry and acquire a crosslinked structure after the electrode sheet is pre-lithiated. Through the functional integration of acrylamide binder and pre-lithiation process, the first irreversible capacity loss of the battery is significantly reduced, the initial coulombic efficiency is improved, and the cycle stability is enhanced, thus significantly improving battery performance.

[0085] As shown in Table 1, compared to Example 1, the binder in Comparative Example 1 was not acrylated, and the electrode sheet was not pre-lithiated. The first-cycle coulombic efficiency of Comparative Example 1 decreased by 10%, the cycle capacity retention decreased by 15%, and the specific capacity decreased by approximately 20 mAh / g. In Comparative Example 2, the polyacrylic acid binder in the electrode sheet was not acrylated, and no anionic polymerization reaction was initiated during the lithium naphthalene reagent pre-lithiation process. The binder was not in-situ crosslinked. Compared to Comparative Example 1, although the cycle capacity retention of Comparative Example 2 was significantly improved, the insufficient structural stability of the binder during electrode expansion and contraction resulted in lower specific capacity, first-cycle coulombic efficiency, and cycle capacity retention of the half-cell in Comparative Example 2 compared to Example 1.

[0086] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.

Claims

1. A modified binder for lithium-ion electrode sheets, characterized in that, Including acryloylated or methacrylated polymeric binders, said polymeric binders containing hydroxyl and / or carboxyl groups.

2. The modified binder for lithium-ion electrode sheets as described in claim 1, characterized in that, The polymer binder is at least one of polyacrylic acid, polyvinyl alcohol, sodium alginate, and carboxymethyl cellulose.

3. A method for preparing a modified binder for lithium-ion electrode sheets as described in claim 1 or 2, characterized in that, Includes the following steps: (1) Dissolve the polymer binder in water, stir evenly, and then add acid to adjust the pH to 3-4; (2) Glycidyl acrylate was slowly added to the solution, and the mixture was heated and stirred. Then, organic solvent was slowly added and stirred to promote precipitation of the product. The modified binder was collected by centrifugation.

4. The method for preparing the modified binder for lithium-ion electrode sheets as described in claim 1, characterized in that, In step (1), the mass ratio of the polymer binder to water is 1:(10-30); And / or, in step (1), the mass ratio of the polymer binder to glycidyl acrylate is (2-5):1; And / or, in step (1), the acid is hydrochloric acid, and the concentration of the hydrochloric acid is 0.05-1 mol / L; And / or, in step (2), the heating temperature is 40-60℃ and the reaction time is 12-48h; And / or, in step (2), the volume ratio of organic solvent to water is (1-3):1; And / or, in step (2), the organic solvent is at least one of acetone, acetonitrile, methanol, and ethanol.

5. A lithium-ion electrode sheet, characterized in that, The modified binder for lithium-ion electrode sheets includes the modified binder for lithium-ion electrode sheets as described in any one of claims 1-2, or the modified binder for lithium-ion electrode sheets prepared by the preparation method of the modified binder for lithium-ion electrode sheets as described in any one of claims 3-4.

6. The lithium-ion electrode sheet as described in claim 5, characterized in that, It includes active materials, modified binders and conductive agents in a mass ratio of (2-5):(0.5-2):(0.5-2).

7. The lithium-ion electrode sheet as described in claim 5, characterized in that, The active material is at least one of carbon-based compounds, silicon-based compounds, and transition metal nitrides; And / or, the conductive agent is at least one of carbon nanotubes, conductive carbon black, conductive graphite, acetylene black, and graphene.

8. A method for preparing a lithium-ion electrode sheet as described in any one of claims 5-7, characterized in that, Includes the following steps: (1) Grind and mix the active material, conductive agent and modified binder evenly, add water to the mixture and stir evenly to obtain a slurry with a solid content of 10wt%-15wt%. (2) The slurry is uniformly coated on the current collector substrate and dried to obtain an electrode sheet; (3) After cutting the electrode sheet, it is pre-lithiated in lithium naphthalene reagent to obtain lithium-ion electrode sheet.

9. The method for preparing the lithium-ion electrode sheet as described in claim 8, characterized in that, The preparation method of the lithium naphthalene reagent includes the following steps: dissolving metallic lithium and naphthalene in a molar ratio of (1-2):(1-2) in ethylene glycol dimethyl ether to obtain the lithium naphthalene reagent; And / or, the concentration of the lithium naphthalene reagent is 0.3-0.8 mol / L.

10. The application of a lithium-ion electrode sheet prepared by any one of the lithium-ion electrode sheets as described in claims 6-8 or as described in claim 9 in the field of lithium-ion battery preparation.

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