Electrode composition

Abstract

The present invention relates to a composition for the preparation of a cathode or anode of a lithium-ion battery or a sodium-ion battery, said composition comprising a lignin derivative. Furthermore, the present invention relates to (i) the use of a lignin derivative as dispersant in a composition for the preparation of a cathode or anode of a lithium-ion battery or a sodium-ion battery, (ii) the use of a lignin derivative for reducing the shear rate of a composition for the preparation of a cathode or anode of a lithium-ion battery or a sodium-ion battery, (iii) a cathode or anode of a lithium-ion battery or a sodium-ion battery prepared from the composition of the present invention, (iv) a lithium-ion battery or a sodium-ion battery comprising the electrode of the present invention, and (v) a method for the preparation of a cathode or anode of a lithium-ion battery or a sodium-ion battery.

Description

Technical Field

[0001] This invention relates to a composition for preparing a positive or negative electrode of a lithium-ion battery or a sodium-ion battery, said composition comprising a lignin derivative. Furthermore, this invention relates to (i) the use of a lignin derivative as a dispersant in a composition for preparing a positive or negative electrode of a lithium-ion battery or a sodium-ion battery, (ii) the use of a lignin derivative to reduce the shear rate of a composition for preparing a positive or negative electrode of a lithium-ion battery or a sodium-ion battery, (iii) a positive or negative electrode of a lithium-ion battery or a sodium-ion battery prepared from the composition of this invention, (iv) a lithium-ion battery or a sodium-ion battery comprising the electrode of this invention, and (v) a method for preparing a positive or negative electrode of a lithium-ion battery or a sodium-ion battery. Background Technology

[0002] Electrodes for lithium-ion and sodium-ion batteries (also known as "Li-ion" and "Na-ion" batteries) are typically prepared by coating a current collector (e.g., copper or aluminum foil) with an electrode slurry and drying the resulting coated current collector to remove solvent and form a solid electrode layer. This solid electrode layer can be further compressed using a calendering process to improve the electrode's mechanical stability and density. Finally, the electrode is cut to the desired shape and size. The electrode slurry typically contains active materials, conductive additives, and a binder suspended in a solvent. Other components may also be present.

[0003] Environmental and safety considerations make aqueous electrode slurries desirable; that is, it is generally expected that the solvent for electrode slurries is water or contains water. However, due to their physicochemical properties (e.g., particle size, surface charge, or surface functionalization), many active materials—such as lithium metal oxides used as positive electrode active materials in lithium-ion batteries—aggregate / flocculate in aqueous slurries, negatively impacting rheology and hindering the formation of a uniform coating when cast onto a current collector. Specifically, such aggregation / agglomeration between particles can occur in water due to hydrogen bonding and strong electrostatic forces. This should be avoided to ensure electrode consistency and high quality. Furthermore, particle aggregation / agglomeration leads to poor contact between the active material and conductive additives, resulting in poor conductivity and increased viscosity of the electrode slurry.

[0004] Compared to water, organic solvents such as N-methylpyrrolidone (NMP) have a significantly lower capacity to accommodate hydrogen bonds and are less polar. Therefore, organic systems, especially N-methylpyrrolidone (NMP), remain the industry standard.

[0005] In particular, industrial solutions have traditionally used polyvinylidene fluoride (PVDF), a polymer with mutagenic and teratogenic properties, as a binder to disperse active materials in expensive, unsustainable, and hazardous NMP. A related challenge for slurry processing in NMP is the need for uniform dispersion of the carbon component, which typically requires the use of hazardous and expensive synthetic materials.

[0006] Therefore, renewable and harmless materials are needed that can disperse active materials in aqueous solutions. Furthermore, in order to be (directly) applicable to currently used technologies, it is desirable that the dispersant also functions well in NMP solutions.

[0007] However, there is a particular and widespread expectation to prepare electrodes from aqueous slurries to reduce manufacturing costs, hazards, and environmental impact. If electrodes can be prepared from water-based slurries, costs will be significantly reduced, and the process of recycling NMP will be eliminated. Furthermore, aqueous processing allows for the replacement of expensive and toxic synthetic PVDF binders with lower-cost bio-based binders such as carboxymethyl cellulose (CMC) or xanthan gum, further contributing to lower overall electrode costs and making the manufacturing process more environmentally friendly. Summary of the Invention

[0008] The purpose of this invention is to achieve all or part of the above-mentioned objectives.

[0009] In particular, an object of the present invention is to provide a renewable and harmless dispersant that can disperse active materials in aqueous solutions. Another object of the present invention is to provide a renewable and harmless dispersant that functions in both aqueous and NMP solutions. Yet another object of the present invention is to provide a positive or negative electrode composition (also referred to as a "slurry") with good rheological and coating properties.

[0010] The above and other objectives have been achieved by the claimed composition for preparing a positive or negative electrode of a lithium-ion battery or a sodium-ion battery, which uses a lignin derivative as a dispersant.

[0011] The inventors of this invention have discovered that lignin derivatives, particularly sulfonated lignin (such as lignin sulfonates), perform exceptionally well as dispersants in aqueous and NMP-based electrode slurries. Unlike fossil-based dispersants currently used in the prior art, lignin derivative dispersants are produced from renewable resources (i.e., wood) and have a significantly lower CO2 footprint than their fossil-based counterparts. Therefore, their use will contribute to reducing CO2 emissions during battery manufacturing processes.

[0012] Furthermore, lignin derivatives have been found to effectively disperse various active materials, such as carbon-based materials (for the negative electrode) and lithium metal oxides (for the positive electrode), in water or NMP, as evidenced by the reduction in slurry viscosity. A homogeneous electrode with uniformly dispersed components can then be cast from this slurry. An unexpected benefit of this is the ability to cast the slurry at very high concentrations—approximately twice the concentrations reported in other literature.

[0013] In addition, lignin-based dispersants have been found to be particularly effective in cathode slurries used in lithium-ion or sodium-ion batteries.

[0014] In a first aspect, the present invention relates to a composition for preparing a positive or negative electrode for a lithium-ion battery or a sodium-ion battery.

[0015] In a second aspect, the present invention relates to the use of lignin derivatives as dispersants in compositions for preparing positive or negative electrodes (preferably positive electrodes) of lithium-ion or sodium-ion batteries.

[0016] In a third aspect, the present invention relates to the use of lignin derivatives for reducing the viscosity of compositions used in the preparation of positive or negative electrodes for lithium-ion or sodium-ion batteries.

[0017] In a fourth aspect, the present invention relates to a positive or negative electrode of a lithium-ion battery or a sodium-ion battery prepared from the composition of the present invention.

[0018] In a fifth aspect, the present invention relates to a lithium-ion battery or a sodium-ion battery comprising the electrodes of the fourth aspect.

[0019] In a sixth aspect, the present invention relates to a method for preparing a positive or negative electrode. Attached Figure Description

[0020] Figure 1 A schematic diagram of lignin sulfonate molecules obtained from sulfite pulping is shown.

[0021] Figure 2 The rheological properties of slurries containing aqueous dispersions of three different lithium-ion cathode active materials are shown. Slurry profiles containing 0.2 wt% lignin sulfonate dispersant (“Vanisperse LI” from Borregaard) are presented. , and Indicated. Pulps that do not contain lignin sulfonate are... , and express.

[0022] Figure 3The slurry rheology of NMP-dispersions of KS-6 graphite (75% by volume) dispersed with different doses of lignin sulfonic acid is shown.

[0023] Figure 4 The slurry rheology of NMP dispersions of KS-6 graphite (added at 75 vol%) dispersed with different doses of hardwood-derived sodium lignin sulfonate was shown.

[0024] Figure 5 The slurry rheology of NMP dispersions of KS-6 graphite (added at 75% by volume) dispersed with different doses of kraft paper lignin is shown.

[0025] Figure 6 The rheological properties of slurries of KS-6 graphite (75% by volume) dispersed with either 5% by weight NMP-soluble lignin sulfonic acid or 5% by weight lignin sulfonate (which has very low solubility in NMP) are shown. Figure 6 The NMP-labeled soluble lignin is the acidified form of insoluble lignin sulfonate.

[0026] Figure 7 The rheological properties of slurries containing 50% by weight of hard carbon with different doses of lignin sulfonate were shown. Detailed Implementation

[0027] As stated above, this invention is based on the surprising discovery that lignin derivatives—such as sulfonated lignin (e.g., lignin sulfonate or lignin sulfonic acid)—perform very well as dispersants in aqueous and NMP-based electrode slurries. In particular, these lignin derivatives have been found to be especially effective in positive electrode slurries for lithium-ion or sodium-ion batteries.

[0028] It is hypothesized that lignin derivatives, particularly charged lignin derivatives, act as dispersants by forming a hydrated shell around particulate components in aqueous solutions. The ability of charged lignin to form a hydrated shell is attributed to its dual function of polymorphism with significantly polar and nonpolar functional groups.

[0029] Because NMP has a significantly lower capacity to accommodate hydrogen bonds and is less polar than water, its ability to dissolve cationic substances (providing charge balance for lignin sulfonates) is very limited. Therefore, lignin derivatives are not expected to be effective dispersants in NMP-based slurries. The unexpectedly good dispersing ability of lignin derivatives in NMP is presumably mainly due to steric interactions.

[0030] In particular, lignin-derived dispersants have been found to reduce the viscosity of slurries at various cathode materials and at all shear rates, thereby allowing for uniform casting of slurries at very high concentrations (approximately twice the concentrations reported in other literature).

[0031] In a first aspect, the present invention relates to a composition for preparing a positive or negative electrode for a lithium-ion battery or a sodium-ion battery. The composition comprises (a) a lignin derivative, (b) at least one active material, and (c) a solvent.

[0032] The composition used to prepare the electrode exists in the form of a slurry, and is therefore also referred to in the art as "electrode slurry", "electrode slurry composition", etc.

[0033] Preferably, the composition is used to prepare the positive electrode of a lithium-ion battery or a sodium-ion battery. Alternatively, in other words, the present invention preferably relates to a positive electrode slurry for preparing a lithium-ion battery or a sodium-ion battery. More preferably, the composition is used to prepare the positive electrode of a lithium-ion battery (i.e., a positive electrode slurry for lithium-ion batteries). Alternatively, the composition can be used to prepare the positive electrode of a sodium-ion battery.

[0034] In one embodiment, the composition may be a composition for preparing a positive or negative electrode (preferably a positive electrode) of a lithium-ion battery. In another embodiment, the composition may be a composition for preparing a positive or negative electrode (preferably a positive electrode) of a sodium-ion battery.

[0035] As described above, the unexpected benefit of using lignin derivatives as dispersants is the ability to uniformly cast slurries at very high concentrations—approximately twice the concentrations reported in other literature. Therefore, the solvent is preferably present in an amount of 10 to 90% by weight, preferably 20 to 80% by weight, more preferably 40 to 60% by weight, and even more preferably 45 to 55% by weight, based on the total weight of the composition. Thus, the present invention allows for the use of relatively small amounts of solvent, making the entire process more environmentally friendly and economical.

[0036] For environmental and safety reasons, aqueous electrode slurries are particularly desirable. Therefore, it is preferable that the solvent is water or contains water. Preferably, the solvent is water. As can be seen from the examples, the inventors have found that lignin derivatives are indeed suitable dispersants in aqueous systems, even at very high solids contents.

[0037] In addition, the dispersant is preferably applicable to existing processes and technologies without requiring fundamental modifications to the process. Therefore, in another embodiment, the solvent is N-methylpyrrolidone (NMP) or contains N-methylpyrrolidone (NMP). In this embodiment, the solubility of the lignin derivative is preferably greater than 1 g / 100 mL NMP (20°C), more preferably greater than 5 g / 100 mL NMP, and even more preferably greater than 10 g / 100 mL NMP.

[0038] However, from a long-term perspective and for environmental and safety considerations, it is preferable that the composition does not contain N-methylpyrrolidone (NMP).

[0039] Also for environmental and safety reasons, it is preferable that the composition does not contain polyvinylidene fluoride (PVDF).

[0040] The lignin derivative is preferably sulfonated lignin, carboxylated lignin, hydrolyzed carboxylated lignin, or amine-functionalized lignin.

[0041] Kraft paper lignin can also be used in this invention.

[0042] Preferably, the lignin derivative is sulfonated lignin. The sulfonated lignin is preferably lignin sulfonate or sulfonated kraft paper lignin, more preferably lignin sulfonate. Particularly preferably, the sulfonated lignin is sodium lignin sulfonate, calcium lignin sulfonate, ammonium lignin sulfonate, magnesium lignin sulfonate, lignin sulfonic acid, or any combination thereof, preferably sodium lignin sulfonate or lignin sulfonic acid.

[0043] Preferably, the lignin derivative is sodium lignin sulfonate obtained by sulfite pulping, preferably obtained by sulfite pulping of softwood or hardwood, and more preferably obtained by sulfite pulping of softwood.

[0044] Lignin (also known as "natural lignin") is one of the most abundant organic materials in nature, providing strength and support for trees and other plants. Lignin is sometimes referred to as the "glue" in the cellulose skeleton. Chemically, lignin is a complex organic polymer.

[0045] Therefore, according to the present invention, the term "lignin" refers to a biopolymer or mixture of biopolymers present in the supporting tissues of plants, particularly in the cell walls that provide rigidity to the plant. Lignin is a phenolic polymer, or a mixture of phenolic polymers. The composition of lignin depends on the plant and therefore varies depending on the plant from which it originates. Naturally occurring forms of lignin, i.e., those present in plants, are hydrophobic and aromatic. There are no limitations regarding the source of lignin.

[0046] According to the present invention, the term "lignin derivative" should be understood to refer to any lignin that no longer exists in its natural form but has undergone a chemical derivatization process. Methods for preparing chemically modified lignin are generally known in the art, such as sulfite pulping.

[0047] As described above, a preferred example of a lignin derivative is sulfonated lignin, preferably lignin sulfonate. Lignosulfonates are obtained when lignin or lignin-containing cellulose biomass is subjected to sulfite cooking. Therefore, lignin sulfonates can be described as organic salt products recovered from wood digestion (e.g., acid or alkaline sulfite pulping with sulfite). Therefore, preferred lignin sulfonates can be described as anionic polyelectrolyte polymers. Therefore, as used in the context of this application, the term "lignin sulfonate" refers to any lignin derivative formed during sulfite pulping of lignin-containing materials (e.g., wood) in the presence of, for example, sulfur dioxide and sulfite or bisulfite ions. For example, during acidic sulfite pulping of lignin-based materials, electrophilic carbocations are generated in lignin as a result of acid-catalyzed ether cleavage. Therefore, lignin can react with these carbocations to form lignin sulfonates. Another common approach to obtaining sulfonated lignin is to sulfonate lignin that has already been extracted from biomass by other methods (e.g., Kraft lignin or organic solvent lignin). Direct sulfonation of the extracted lignin can be achieved through sulfite pulping or other reactions known in the art that introduce sulfonate groups (e.g., sulfonylation).

[0048] Sulfite pulping is widely known in the field of wood / plant material processing. It is advantageously used to convert nearly pure cellulose fibers from lignocellulosic biomass (i.e., plant material) into wood pulp. This pulping is typically achieved by extracting lignin from lignocellulosic biomass using various sulfites in a large pressure vessel called a digester. During sulfite pulping, lignin molecules are sulfonated, thus becoming negatively charged and generally water-soluble. In sulfite pulping, sulfonate groups are typically introduced into the aliphatic portion of lignin, rather than the aromatic portion. Therefore, the lignin sulfonates obtained from sulfite pulping contain little or no aromatic sulfonate groups, but only or substantially only aromatic sulfonate groups. Fat Sulfonate groups. Furthermore, during sulfite pulping, carboxylate groups are introduced into natural lignin.

[0049] According to the present invention, "sulfite pulping" refers to the process of extracting or reacting lignin in natural lignin or kraft pulp with at least one sulfite. The salt used in the pulping process is preferably a sulfite (SO32-). 2-) or bisulfite (HSO3) - As mentioned above, sulfite pulping typically introduces sulfonate groups into the aliphatic portion of lignin, rather than the aromatic portion.

[0050] As mentioned in this article, " Aliphatic sulfonate groups " is a sulfonate group attached to an aliphatic carbon atom (i.e., a carbon atom that is not part of an aromatic ring). In contrast, as mentioned in this article, " Aromatic sulfonate groups " is a sulfonate group attached to a carbon atom that is part of an aromatic ring.

[0051] As mentioned above, kraft lignin or sulfonated kraft lignin are also suitable lignin derivatives. Kraft lignin is precipitated from the alkaline pulping liquor of kraft paper, particularly from the kraft paper pulping process, in which the lignin has decomposed from its natural form present in the wood pulp, representing molecular fragments of the original biopolymer. Therefore, kraft lignin can be described as precipitated, unsulfonated alkaline lignin. Kraft lignin differs structurally and chemically from lignin sulfonates; for example, kraft lignin is insoluble in water. Therefore, if kraft lignin is to be used in an aqueous medium, it is preferable to further sulfonate the kraft lignin (i.e., sulfonated kraft lignin). In embodiments, such sulfonated kraft lignin can be obtained by treating kraft lignin with alkali metal sulfites and alkyl aldehydes at elevated temperatures and / or pressures. Furthermore, kraft lignin has been found to be a suitable dispersant in NMP-based media.

[0052] As mentioned in this article, the sulfonate group is a group with the chemical formula -SO3R', where R' is selected from alkali metal ions or alkaline earth metal ions. In sodium lignosulfonate, R' is a sodium ion. In calcium lignosulfonate, R' is a calcium ion. In ammonium lignosulfonate, R' is an ammonium ion. In magnesium lignosulfonate, R' is a magnesium ion. In lignosulfonic acid, R' is hydrogen. However, in actual electrode pastes, the sulfonate group may exist in its free form (i.e., -SO3). - (This is true.) The use of sulfonate groups also encompasses this and similar cases.

[0053] The lignin derivatives according to the present invention can be obtained in different ways.

[0054] As described above, according to a preferred embodiment, the lignin derivative is obtained by treating natural lignin during a sulfite pulping process, thereby obtaining a lignin derivative having -COOR and sulfonate groups, wherein R is a cation or hydrogen, wherein the cation is preferably an ammonium ion, an alkali metal ion, or an alkaline earth metal ion. R can also be any mixture of the above options. The fact that "R" can be any mixture of ammonium ions, hydrogen, alkali metal ions, and alkaline earth metal ions is due to the fact that the lignin derivative contains multiple -COOR groups, which can exist in different forms. For example, some -COOR groups can exist in the form of -COOH groups, while others exist in the form of salts, such as in the form of -COONa groups. Generally, the -COOR group can be described as a carboxylic acid group or a salt thereof. However, as those skilled in the art will know, in solution, -COOR is likely to exist in its deprotonated form (i.e., -COO). - It exists. When this invention refers to the -COOR group, this form is also covered. Figure 1 A schematic diagram of lignin sulfonate molecules obtained from sulfite pulping is shown.

[0055] According to one embodiment, the lignin derivative does not contain -COOR groups and / or sulfonate groups derived from lignin raw materials or the sulfite pulping process. Preferably, the lignin derivative does not contain sulfonate groups and -COOR groups derived from the sulfite pulping process.

[0056] The lignin derivatives particularly advantageous for this invention are: (i) lignin sulfonates treated with at least one additional chemical or thermal treatment step, or (ii) sulfonated kraft paper lignin treated with at least one additional chemical or thermal treatment step. The chemical treatment step is preferably selected from oxidation and sulfonation. This further enhances the polarity and hydrophilicity of the lignin derivative. In a preferred embodiment, the oxidation step is selected from at least one of the following: oxidation with air (oxygen) and / or periodate, peroxide, ozone, etc. (optionally at elevated temperatures), TEMPO oxidation (optionally in the presence of an oxidation catalyst), and other methods and reagents known to those skilled in the art for oxidizing cellulosic biomass.

[0057] As also mentioned above, the lignin sulfonate can be a lignin sulfonate obtained by sulfite pulping. As referred to herein, "lignin sulfonate obtained by sulfite pulping" means a lignin sulfonate with a chemical structure resulting from the sulfite pulping process of natural lignin derived from cellulose. Or, in other words, By Asia Lignosulfonates obtained from sulfate pulping"Lignosulfonates obtained directly from the sulfite pulping process do not require any post-pulping functionalization steps. Therefore, lignin sulfonates obtained by sulfite pulping as a byproduct of cellulose production are "lignin sulfonates obtained from sulfite pulping" in the sense of this invention.

[0058] As mentioned in this article, " Functionalization steps after pulping "It is a sulfite pulping process" after The applied chemical or physical treatment steps alter the molecular structure of lignin sulfonates obtained from sulfite pulping. However, any step applied after sulfite pulping that only increases the purity of lignin sulfonates obtained from sulfite pulping without altering their chemical structure, such as a washing step, is not a "post-pulping functionalization step" in the sense of this application.

[0059] Preferably, the lignin derivative is obtained by treating the lignin sulfonate obtained from sulfite pulping in a post-pulping oxidation step. This means that the lignin sulfonate is first prepared by treating natural lignin in sulfite pulping, and then the lignin sulfonate obtained from sulfite pulping is oxidized in a post-pulping oxidation step. It should be understood that, in this case, no other post-pulping functionalization steps are applied except for washing and other purification steps that do not significantly alter the molecular structure.

[0060] In this embodiment, if the lignin derivative of the present invention is obtained via a sulfite pulping step, no further post-pulping functionalization step is applied. This also means that the lignin derivative does not contain sulfonate groups derived outside of the sulfite pulping process. In particular, this means that the lignin derivative does not contain aromatic sulfonate groups. This embodiment is particularly advantageous because, in this case, lignin sulfonates obtained as a byproduct in the production of cellulose via sulfite pulping can be used, making the lignin derivative highly cost-effective and environmentally friendly. Sulfite pulping is advantageous for the industrial-scale processing of cellulose-based biomass because it is part of an integrated process that not only produces lignin sulfonates but also cellulose pulp that can be further processed to produce valuable products / chemical platforms.

[0061] According to another preferred embodiment, the lignin derivative is prepared by sulfonating kraft paper lignin (i.e., lignin that has already been chemically modified during the kraft paper pulping process). In a preferred embodiment, sulfite pulping is used to sulfonate the kraft paper lignin.

[0062] According to another preferred embodiment, an additional chemical treatment step is performed on the lignin derivative or sulfonated kraft paper lignin obtained from sulfite pulping, wherein the additional step is selected from at least one oxidation step and / or heat treatment step, preferably at least one oxidation step.

[0063] In a preferred embodiment, the oxidation step is selected from at least one of the following: oxidation with air (oxygen) and / or periodate, peroxide, ozone, etc. (optionally at elevated temperatures), TEMPO oxidation (optionally in the presence of an oxidation catalyst), and other methods and reagents known to those skilled in the art for oxidizing cellulosic biomass.

[0064] Preferably, based on dry matter, the lignin derivative contains more than 4% by weight, more preferably more than 8% by weight, even more preferably more than 12% by weight, even more preferably more than 14% by weight -COOR groups. The amount of -COOR groups is determined by potentiometric titration as described in Methods in Lignin Chemistry, Stephen Y. Lin and Carlton W. Dence, Springer-Verlag Berlin Heidelberg, 1992, pp. 458-464 (see Experimental Section).

[0065] Furthermore, based on dry matter content, the lignin derivative preferably contains less than 6% by weight, more preferably less than 4% by weight, and even more preferably less than 2% by weight of organosulfur groups. The amount of organosulfur groups is determined according to the method described in the experimental section.

[0066] Furthermore, based on the total weight of the lignin derivative, the lignin derivative preferably contains less than 6% by weight, preferably equal to or less than 5.0% by weight, and more preferably less than 5.0% by weight of methoxy groups. More preferably, based on the total weight of the oxidized sulfonated lignin, the amount of methoxy groups is equal to or less than 4.0% by weight, preferably less than 4.0% by weight. The amount of organomethoxy groups is determined according to the method described in the experimental section.

[0067] The combination of lignin sulfonic acid and N-methylpyrrolidone (NMP) as a solvent has been shown to yield good results. Therefore, preferably, if the solvent is N-methylpyrrolidone (NMP), the lignin derivative is lignin sulfonic acid. Thus, according to a preferred embodiment, the sulfonated lignin derivative is lignin sulfonic acid, and the solvent is N-methylpyrrolidone (NMP).

[0068] The solubility of molecules can be a useful method for understanding and describing their physicochemical properties. The ability to quantify molecular solubility comes from the Hildebrand solubility parameter, which is defined as the square root of the cohesive energy density, see J.H. Hildebrand and RL. Scott, The Solubility of Noneelectrolytes, 3rd edition, 1950.

[0069] The assumptions made to define the Hildebrand parameter limit its applicability due to its origin in hydrocarbons. Specifically, contributions from hydrogen bonding and solvent polarity are not included. The Hansen solubility parameter (HSP) decomposes the cohesive energy density into dispersive, polar, and hydrogen bonding components, as described in *Hansen Solubility Parameters, A User's Handbook*, 2nd edition, 2007, https: / / www.hansen-solubility.com / HSP-science / for-beginners.php (excerpts of which are shown in Appendix 1) and https: / / www.hansen-solubility.com / HSP-science / sphere.php (excerpts of which are shown in Appendix 2).

[0070] The HSP distance between two molecules is called R. a And quantify their similarity. Having similar HSP values, thus R a Molecules with smaller values ​​are soluble in each other. The formula for Ra is:

[0071] Where δ D Dispersion parameter, δ P Polarization parameter, δ H This refers to the hydrogen bond parameters of two different molecules, 1 and 2. Note that δ... D The previous coefficient 4 is correct and has reasonable theoretical and experimental basis as described in the above references.

[0072] The HSP value of any molecule can be determined experimentally: attempt to dissolve a certain amount of the molecule in different solvents and observe which solvents successfully dissolve the molecule. The average of the corresponding δ values ​​of the solvents that dissolved the molecule provides the corresponding δ value of the molecule. This method is described in BO Myrvold's "The Hansen solubility of some lignosulfonates," ResearchGate, 2014, 303264402.

[0073] For NMP-soluble lignin sulfonic acid, the measured HSP values ​​were 17.7, 13.4, and 13.7 MPa. 1 / 2 . Lignosulfonic acid and NMP R a 6.6 MPa 1 / 2 Since lignin sulfonic acid is soluble in NMP, it is obvious that 6.6 MPa... 1 / 2 or lower R a This indicates that lignin is soluble in NMP. In solvents that successfully dissolve lignin sulfonic acid, ethylene glycol's R... a The maximum value is 12.6 MPa. 1 / 2 This indicates that R is as high as 12.6 a It is still suitable to dissolve lignin in NMP.

[0074] Preferred lignin or lignin sulfonic acid with NMP R a Less than 13 MPa 1 / 2 More preferably less than 7 MPa 1 / 2 The optimal value is less than 1 MPa. 1 / 2 .

[0075] Water is a solvent that is particularly difficult to express accurately using HSP, and several different values ​​have been reported. According to *Hansen Solubility Parameters, A User's Handbook*, 2nd edition, 2007, by CM Hansen, the HSP parameters for water used here are 15.5, 16.0, and 42.3 MPa. 1 / 2 .

[0076] Representative water-soluble lignin derivatives were identified with strengths of 19.8, 13.6, and 21.7 MPa. 1 / 2 The HSP value, relative to the R of water a 22.5 MPa 1 / 2 Other water-soluble lignin derivatives R a Value as high as 28.8 MPa 1 / 2 For example, BO Myrvold, ResearchGate The HSP value of the water mentioned above was used, as reported in 2014, 303264402.

[0077] Therefore, water-soluble lignin derivatives with water are preferred. a Less than 29 MPa 1 / 2 More preferably less than 23 MPa 1 / 2 The optimal value is less than 1 MPa. 1 / 2 .

[0078] R calculated between representative water-soluble lignin derivatives and lignin sulfonic acid a The value is 9.0 MPa 1 / 2 These two lignin materials exhibit significantly different solubilities in NMP.

[0079] Therefore, NMP-soluble lignin or lignin sulfonic acid is preferably present relative to HSP values ​​of 17.7, 13.4, and 13.7 MPa. 1 / 2 R a 9.0 MPa 1 / 2 , more preferably R a Value less than 6 MPa 1 / 2 The optimal value is less than 1 MPa. 1 / 2 .

[0080] Therefore, water-soluble lignin derivatives are preferred relative to 19.8, 13.6, and 21.7 MPa. 1 / 2 R a Less than 9.0 MPa 1 / 2 More preferably less than 6 MPa 1 / 2 The optimal value is less than 1 MPa. 1 / 2 .

[0081] It has been found that small amounts of lignin derivatives are sufficient to achieve the desired results. Therefore, preferably, the lignin derivatives are present in a dry weight of 0.01% to 10% by weight, based on the total weight of the composition.

[0082] Preferably, the lignin derivative is present in dry matter at 0.01% to 4.5% by weight, preferably 0.01% to 1.0% by weight, and more preferably 0.01% to 0.5% by weight, based on the total weight of the composition.

[0083] Particularly preferably, the lignin derivative is present in dry matter at 0.01 wt% to 4.5 wt%, preferably 0.01 wt% to 4.0 wt%, more preferably 0.01 wt% to 3.5 wt%, more preferably 0.01 wt% to 3.0 wt%, more preferably 0.01 wt% to 2.5 wt%, more preferably 0.01 wt% to 2.0 wt%, more preferably 0.05 wt% to 1.5 wt%, more preferably 0.05 wt% to 1.0 wt%, more preferably 0.05 wt% to 0.8 wt%, more preferably 0.05 wt% to 0.7 wt%, more preferably 0.07 wt% to 0.7 wt%, 0.07 wt% to 0.6 wt%, more preferably 0.07 wt% to 0.6 wt%, more preferably 0.08 wt% to 0.4 wt%, more preferably 0.1 wt% to 0.3 wt%.

[0084] Preferably, the composition further comprises an adhesive and / or a thickener, preferably both, wherein the adhesive is preferably selected from carboxymethyl cellulose (CMC), styrene-butadiene rubber (SBR), and xanthan gum.

[0085] It has been found that a small amount of CMC is sufficient to achieve the desired results. Therefore, if the composition contains CMC, it is preferable that the CMC is present in an amount of less than 5% by weight, preferably less than 4% by weight, based on the total dry weight of the composition.

[0086] Preferably, the composition comprises a metal, preferably one or more of cobalt, nickel, iron, or manganese. In one embodiment, the composition comprises a metal oxide and / or a metal phosphate.

[0087] Furthermore, the composition preferably contains hard carbon.

[0088] According to a preferred embodiment, the composition further comprises a conductive carbon additive. Preferably, the conductive carbon additive is selected from carbon black, graphite, graphene, carbon nanotubes, silicon / carbon composites, or combinations thereof.

[0089] The active material is preferably selected from carbon or carbonaceous materials, especially graphite; silicon or silicon-based materials; lithium; sodium; lithium or sodium alloys; lithium or sodium metal oxides, including composite oxides and mixed metal oxides; or any combination of all or some of the foregoing materials.

[0090] According to a preferred embodiment, the active material is selected from lithium metal oxides and / or lithium metal phosphates. Preferably, the active material is selected from lithium cobalt oxide (LiCoO2), lithium manganese oxide (LiMn2O4), lithium nickel oxide (LiNiO2), lithium nickel manganese cobalt oxide (Li-NMC), lithium iron phosphate (LiFePO4), lithium nickel cobalt aluminum oxide (LiNiCoAlO2), or combinations thereof.

[0091] According to another embodiment, the active material is selected from sodium titanate (Na2Ti3O7), sodium vanadate (Na3V2(PO4)3), sodium iron phosphate (NaFePO4), sodium nickel manganese cobaltate (Na(Ni 0.5 Mn 0.5 Sodium copper ferrocyanide (Na2CuFe(CN)6), sodium manganate (Na2MnO4), sodium cobaltate (NaCoO2), sodium ferrite (NaFeO2), sodium cuprate (NaCuO2), sodium titanate (Na4Ti5O) 12 Sodium phosphorus nitrogen oxide (NaPON), sodium sulfide (Na2S), and sodium niobate (Na4Nb2O7).

[0092] Polyacrylic acid is sometimes used in electrode compositions. However, it has been found that a relatively small amount of polyacrylic acid is sufficient to achieve the desired effect if desired. Therefore, if the composition contains polyacrylic acid or a salt thereof, it is preferably present in an amount of less than 20% by weight, preferably less than 10% by weight, based on the weight of the sulfonated lignin derivative. Preferably, the composition does not contain polyacrylic acid or a salt thereof.

[0093] According to a preferred embodiment, the at least one active material is coated with a conductive material, preferably carbon.

[0094] Preferably, the at least one active material exists in particulate form. Preferably, the average diameter of the particles is from 1.5 μm to 12.0 μm and / or 90% of the particles are 25 μm or smaller. The particle size can be determined by dynamic light scattering.

[0095] In a second aspect, the present invention relates to the use of lignin derivatives as dispersants in compositions for preparing positive or negative electrodes of lithium-ion or sodium-ion batteries.

[0096] According to the first aspect, the second aspect preferably relates to the use of lignin derivatives as dispersants in compositions for preparing the positive electrode of lithium-ion batteries or sodium-ion batteries (preferably lithium-ion batteries).

[0097] As mentioned above, "compositions for preparing positive or negative electrodes of lithium-ion or sodium-ion batteries" are also referred to in the art as "electrode slurry", "electrode slurry composition", etc.

[0098] In a third aspect, the present invention relates to the use of lignin derivatives for reducing the shear rate of compositions used in the preparation of positive or negative electrodes for lithium-ion or sodium-ion batteries.

[0099] Similarly, the composition is preferably a composition for preparing a positive electrode for a lithium-ion battery or a sodium-ion battery (preferably a lithium-ion battery).

[0100] In a fourth aspect, the present invention relates to a positive or negative electrode for a lithium-ion battery or a sodium-ion battery. The electrode is prepared from the composition of the present invention.

[0101] Consistent with the first aspect, the electrode is preferably a positive electrode.

[0102] In a fifth aspect, the present invention relates to a lithium-ion battery or a sodium-ion battery comprising the electrodes of the fourth aspect. Preferably, the battery is a lithium-ion battery.

[0103] In a sixth aspect, the present invention relates to a method for preparing a positive or negative electrode (preferably a positive electrode) for a lithium-ion battery or a sodium-ion battery. The method comprises the steps of: (1) applying the composition of the present invention onto a substrate, and (2) drying the composition.

[0104] Preferably, the method includes step (3) compressing the product obtained in step (2) using a calendering process.

[0105] The present invention will now be further described by the following: 1. A composition for preparing a positive or negative electrode of a lithium-ion battery or a sodium-ion battery, said composition comprising: (a) Lignin derivatives, (b) at least one active material, and (c) Solvent.

[0106] 2. The composition as described in claim 1, wherein the solvent is present in an amount of 10 to 90% by weight, preferably 20 to 80% by weight, more preferably 40 to 60% by weight, or even more preferably 45 to 55% by weight, based on the total weight of the composition.

[0107] 3. The composition as described in claim 1 or 2, wherein the solvent is water or contains water, preferably water.

[0108] 4. The composition as described in claim 1 or 2, wherein the solvent is N-methylpyrrolidone (NMP) or contains N-methylpyrrolidone (NMP).

[0109] 5. The composition according to any one of items 1-3, characterized in that the composition does not contain N-methylpyrrolidone (NMP).

[0110] 6. The composition as described in any of the preceding claims, characterized in that the composition does not contain polyvinylidene fluoride (PVDF).

[0111] 7. The composition as described in any of the preceding claims, wherein the composition is a slurry, particularly a positive electrode slurry.

[0112] 8. The composition as described in item 7, wherein the slurry is an aqueous slurry.

[0113] 9. The composition as described in any of the preceding claims, wherein the lignin derivative is sulfonated lignin, carboxylated lignin, hydrolyzed carboxylated lignin, or amine-functionalized lignin.

[0114] 10. The composition as described in any of the preceding claims, wherein the lignin derivative is sulfonated lignin.

[0115] 11. The composition as described in item 10, wherein the sulfonated lignin is lignin sulfonate, lignin sulfonic acid, or sulfonated kraft paper lignin, preferably lignin sulfonate.

[0116] 12. The composition of claim 10, wherein the sulfonated lignin is sodium lignin sulfonate, calcium lignin sulfonate, ammonium lignin sulfonate, magnesium lignin sulfonate, lignin sulfonic acid, or any combination thereof, preferably sodium lignin sulfonate or lignin sulfonic acid.

[0117] 13. The composition of claim 10, wherein the sulfonated lignin is: (i) a lignin sulfonate treated with at least one additional chemical or thermal treatment step, or (ii) a sulfonated kraft paper lignin treated with at least one additional chemical or thermal treatment step.

[0118] 14. The composition as described in item 13, wherein the chemical treatment step is selected from oxidation and sulfonation.

[0119] 15. The composition as described in any of the preceding claims, wherein the lignin derivative is lignin sulfonic acid and the solvent is N-methylpyrrolidone (NMP).

[0120] 16. The composition as described in any of the preceding claims, wherein the lignin derivative is present in a dry weight of 0.01% to 10% by weight based on the total weight of the composition.

[0121] 17. The composition as described in claim 16, wherein the lignin derivative is present in a dry weight of 0.01% to 4.5% by weight, preferably 0.01% to 1.0% by weight, and more preferably 0.01% to 0.5% by weight, based on the total weight of the composition.

[0122] 18. The composition as described in claim 16, wherein the lignin derivative is present, based on the total weight of the composition, in a dry matter weight of 0.01 wt% to 4.5 wt%, preferably 0.01 wt% to 4.0 wt%, more preferably 0.01 wt% to 3.5 wt%, more preferably 0.01 wt% to 3.0 wt%, more preferably 0.01 wt% to 2.5 wt%, more preferably 0.01 wt% to 2.0 wt%, more preferably 0.05 wt% to 1.5 wt%, more preferably 0.05 wt% to 1.0 wt%, more preferably 0.05 wt% to 0.8 wt%, more preferably 0.05 wt% to 0.7 wt%, more preferably 0.07 wt% to 0.7 wt%, 0.07 wt% to 0.6 wt%, more preferably 0.07 wt% to 0.6 wt%, more preferably 0.08 wt% to 0.4 wt%, more preferably 0.1 wt% to 0.3 wt%.

[0123] 19. The composition as described in any of the preceding claims, wherein the composition further comprises a binder and / or a thickener.

[0124] 20. The composition of claim 19, wherein the adhesive is selected from CMC, styrene-butadiene rubber (SBR), and xanthan gum.

[0125] 21. The composition as described in any of the preceding claims, provided that if the composition contains CMC, the CMC is present in an amount of less than 5% by weight, preferably less than 4% by weight, based on the total dry weight of the composition.

[0126] 22. The composition as described in any of the preceding claims, wherein the composition further comprises a conductive carbon additive.

[0127] 23. The composition of claim 22, wherein the conductive carbon additive is selected from carbon black, graphite, graphene, carbon nanotubes, silicon / carbon composites, or combinations thereof.

[0128] 24. The composition as described in any of the preceding claims, wherein the active material is selected from lithium metal oxides and / or lithium metal phosphates.

[0129] 25. The composition of claim 24, wherein the active material is selected from lithium cobalt oxide (LiCoO2), lithium manganese oxide (LiMn2O4), lithium nickel oxide (LiNiO2), lithium nickel manganese cobalt oxide (Li-NMC), lithium iron phosphate (LiFePO4), lithium nickel cobalt aluminum oxide (LiNiCoAlO2), or combinations thereof.

[0130] 26. The composition as described in any of the preceding claims, provided that if the composition contains polyacrylic acid or a salt thereof, the polyacrylic acid or a salt thereof is present in an amount of less than 20% by weight, preferably less than 10% by weight, based on the weight of the lignin derivative.

[0131] 27. The composition as described in any of the preceding claims, wherein the composition does not contain polyacrylic acid or a salt thereof.

[0132] 28. The composition as described in any of the preceding claims, wherein the at least one active material is coated with a conductive material, preferably carbon.

[0133] 29. The composition as described in any of the preceding claims, wherein the at least one active material is present in particulate form.

[0134] 30. The composition of claim 29, wherein the average diameter of the particles is from 1.5 μm to 12.0 μm and / or 90% of the particles are 25 μm or smaller.

[0135] 31. The composition as described in any of the preceding claims, wherein the composition is used to prepare a positive electrode for a lithium-ion battery.

[0136] 32. Use of lignin derivatives as dispersants in compositions for the preparation of positive or negative electrodes, preferably positive electrodes, of lithium-ion or sodium-ion batteries.

[0137] 33. Use of lignin derivatives to reduce the shear rate of compositions used in the preparation of positive or negative electrodes for lithium-ion or sodium-ion batteries, preferably positive electrodes.

[0138] 34. The use as described in item 32 or 33, wherein the composition is an electrode paste, preferably a positive electrode paste.

[0139] 35. The use as described in any one of items 32-34, wherein the lignin derivative is a lignin derivative as defined in the specification.

[0140] 36. The use as described in any one of items 32-34, wherein the lignin derivative is a lignin derivative as defined in any one of items 9-15.

[0141] 37. A positive or negative electrode for a lithium-ion battery or a sodium-ion battery, preferably a positive electrode, characterized in that it is prepared from the composition of any one of items 1-31.

[0142] 38. A lithium-ion battery or a sodium-ion battery, preferably a lithium-ion battery, characterized in that it comprises the electrode described in item 37, preferably a positive electrode.

[0143] 39. A method for preparing a positive or negative electrode, preferably a positive electrode, for a lithium-ion battery or a sodium-ion battery, the method comprising the following steps: (1) Apply the composition of any one of items 1-31 to a substrate. (2) Dry the composition.

[0144] 40. The method of claim 39, further comprising step (3) compressing the product obtained in step (2) using a calendering process.

[0145] Example

[0146] Example 1 – Aqueous Electrode Slurry

[0147] Prepared with a solid content of 83% by weight (LiCoO2 or LiNiO) 0.4 Mn 0.2 Co 0.2 O2 (commonly known as "NMC") or 63% by weight solids content (LiFePO4) aqueous electrode slurry.

[0148] The rheological properties of the slurries were analyzed by logarithmic scanning of shear rates while maintaining the slurries at 25 °C. The studies were repeated for all slurries, but with the addition of 0.2 wt% lignin sulfonate dispersant (Vanisperse LI from Paulig). The results are shown in... Figure 2 .

[0149] from Figure 2 It can be concluded that all samples exhibit a viscosity reduction of several orders of magnitude at low shear rates, while the viscosity difference of LiFePO4 continues to extend to the highest shear rate measured.

[0150] Example 2 – NMP-based electrode paste

[0151] NMP slurries containing 75% vol% solids (KS-6 graphite) were prepared. The rheological properties of these slurries were analyzed by logarithmic scanning of shear rates while maintaining the slurries at 25 °C. All slurries were studied repeatedly, but with different dosages of lignin-derived NMP-soluble dispersants added as a percentage of the solids weight in the slurry. The following lignin-derived NMP-soluble dispersants were used: (1) lignin sulfonic acid (results are shown in...). Figure 3 (2) Sodium lignosulfonate derived from hardwood (results are shown in...) Figure 4 (3) Kraft paper lignin (results are shown in...) Figure 5 ).

[0152] NMP slurries prepared and analyzed under the same conditions showed that using NMP-soluble lignin (lignin sulfonate) reduced slurry viscosity more effectively than using lignin derivatives insoluble in NMP (lignin sulfonate) (see results). Figure 6 ).

[0153] It can be seen that, for all slurries and all shear rates, the inclusion of lignin derivatives leads to a decrease in slurry viscosity.

[0154] Example 3 – Hard Carbon Slurry

[0155] An aqueous slurry containing 50% by weight of hard carbon was prepared.

[0156] The rheological properties of the slurry were analyzed by logarithmic scanning of the shear rate while maintaining the slurry at 25 °C. All slurries were studied repeatedly, but with the addition of 0.01–0.5 wt% lignin sulfonate dispersant (Vanisperse LI from Paulig) as an example. The results are shown in... Figure 7 .

[0157] from Figure 7 It can be concluded that all samples exhibited a decrease in viscosity, with a 0.5% dose showing a viscosity decrease of several orders of magnitude.

[0158] Methoxyl analysis

[0159] Approximately 30 mg of lignin derivative was dissolved in 1000 mg of deuterated methanol (MeOD-d4), and then added to Amberlite IR-120 resin. The solution was stirred for at least 30 minutes, and then 620 μL was transferred to an NMR tube using an automated pipette. Samples were prepared twice (two parallel samples, each run independently, and the average result was used as the final answer for methoxy content). HSQC experiments were then performed, where methoxy content was calculated based on a linear curve constructed using 20 internal standard methoxy standards. NMR experiments were performed on a Bruker Avance III 500 MHz spectrometer using a selectively reversed-phase (SEI) probe for maximum 1H sensitivity. All spectra were recorded in MeOH-d4 at 300 K. Optimization for methoxy groups was performed. 1 H- 13 C HSQC spectrum ( 1 J C,H The coupling constant was 145 Hz, and echo-antiecho recording was performed in phase-sensitive mode using a standard Bruker pulse sequence. 200 t1 intervals were recorded across 25 experiments, yielding 1 k real data points (24 scans and 16 virtual scans). The relaxation delay was 3 seconds, with a proton spectrum width of 9 ppm and a carbon spectrum width of 130 ppm. The total experimental time was 4.5 hours. Zero-filling was then applied to the 1 k... After 1k data point matrix, squared sinusoidal window functions were applied in both directions. Phase correction was performed on the spectrum in the F2 direction, baseline correction was performed using a 30-degree automatic 5th-order polynomial function in both the F1 and F2 directions, and the summation projection in the F1 direction was calculated. The amount of methoxy groups was determined by the signal intensity in the 53-58 ppm region.

[0160] Organic sulfur analysis

[0161] The amount of "organic" sulfur (org. S), that is, the content of sulfur associated with the sulfonate groups attached to lignin, i.e., the degree of sulfonation, is determined by the following formula based on the difference between total sulfur %S (tot) and inorganic sulfur %S (inorg): %S(org) = %S(tot) -%S(inorg) Total sulfur was determined using an elemental analyzer (e.g., ThermoQuest NCS 2500). An appropriate amount of sample (e.g., 1-2 mg) was placed in a tin capsule along with a suitable catalyst (e.g., vanadium pentoxide). The total sulfur in the sample was then quantified using 2,5-bis(5-tert-butyl-2-benzo-oxazol-2-yl)thiophene (BBOT) standard or other suitable sulfur standards. The sample was then burned at 1400 °C, where all sulfur was oxidized to SO2 and quantified.

[0162] Inorganic sulfur was determined by measuring sulfate in the oxidized sample using ion chromatography with conductivity detection (Dionex instrument, using an IonPac AS11-HC column, 13 mM OH- eluent). 30 mg of sample was weighed into a 50 mL volumetric flask. 10 mL of 0.5% NaOH and 5 mL of 3% H₂O₂ were added to oxidize the inorganic sulfurous anion to sulfate. The sample was then allowed to stand for 12–16 hours to allow the reaction to proceed. Milli-Q water was added, and the pH was neutralized by adding 2 mL of 5% CH₃COOH, followed by dilution to the mark with Milli-Q water. Sulfate standards ranging from 5 mg / L to 80 mg / L were prepared. The sulfate content in the oxidized sample was then determined by ion chromatography according to the instrument manual.

[0163] -COOH was determined using P-NMR.

[0164] Characterizing the molecular structure of lignin sulfonates is often challenging due to the presence of unknown impurities. Specifically, low molecular weight carboxylic acids, such as formic acid and acetic acid (formed from xylose and commonly found in lignin sulfonates), interfere with -COOH measurements.

[0165] Therefore, a slightly modified phosphorus NMR (P-NMR) method was employed, which was originally developed by Argyropoulos, DS, Abacherli, A., Rincón, AG, Arx, UV [quantitative]. 31 p-NMR lignin spectrum (Quantitative) 31P nuclear magnetic resonance (NMR) spectra of lignin, published in Analytical Methods for Lignin Characterisation; International Lignin Institute: Lausanne, Switzerland, 2009, is used to quantitatively determine the density of -COOH groups on the lignin skeleton.

[0166] Specifically, the method includes a purification step to remove low molecular weight carboxylic acid impurities (e.g., formic acid, acetic acid), followed by measurement of the -COOH group density on the lignin polymer using phosphorylation reagents according to Argyropoulos et al. and 31P-NMR.

[0167] Chemicals: Internal standard: Cholesterol, 99% Phosphorylating agent: 2-chloro-4,4,5,5-tetramethyl-1,3,2-dioxaphosphacyclopentane, 95% Deuterated solvent: CDCl3 Solvents: Anhydrous pyridine, 99.8% and anhydrous N,N-dimethylformamide, 99.8%. Desiccant: Molecular sieve 13X, beads, 8-12 mesh Resin: Amberlite IR120 H + type.

[0168] The analysis will be conducted over two days: Day 1: Fill glass pipettes with Amberlite. Rinse the resin twice with 2 x 1 mL deionized water via the pipette. Weigh the sample (200 mg) into a glass vial, add 3 mL of deionized water, and stir for about 10 minutes. Filter the resulting solution through a glass pipette filled with Amberlite, collecting the filtrate in a round-bottom glass flask. Rinse the resin twice with 2 x 1 mL water, also collecting the filtrate in the flask. Freeze and lyophilize the filtered sample overnight. Phosphorylation is highly sensitive to water; all reagents and components must be dried. Hamilton syringes are used to add solvent to the reaction mixture and must be completely dry. Wash the molecular sieve with pure acetone in a glass beaker and then dry it overnight in an oven (105 °C). This will be used the next day to dry the solvent.

[0169] Day 2: Prepare a solvent mixture of N,N-dimethylformamide (DMF) and pyridine (1:1) in a glass vial containing a dried molecular sieve. Seal the vial to prevent moisture. Add the pyridine to another glass vial containing the dried molecular sieve and seal the vial. This will be used to prepare a cholesterol (internal standard) solution (40 mg / mL) in dried pyridine.

[0170] A dry deuterated solvent solution of CDCl3 was prepared by adding deuterated chloroform to a glass vial containing molecular sieves and sealing the vial. Then, 400 μL of dry CDCl3 was transferred to a 2 mL glass vial, followed by the addition of 100 μL of the phosphorylation reagent 2-chloro-4,4,5,5-tetramethyl-1,3,2-dioxaphosphacyclopentane. The freeze-dried sample (30 mg ± 3 mg) was added to the 2 mL vial, followed by a magnetic stir bar and a solvent mixture of DMF:pyridine (1:1) (100 μL), and the mixture was stirred for 30 minutes. Next, a cholesterol solution (100 μL) was added to the reaction mixture, and the mixture was stirred for another 15–30 minutes. Finally, a freshly prepared derivatization reagent solution of CDCl3 (500 μL) was added dropwise, and the reaction mixture was stirred for 1 hour before NMR analysis.

[0171] NMR experiment: 31 The pNMR experiments were conducted using a BBO probe at 300 K. For a 500 MHz Avance III Bruker instrument, the NMR experimental setup was as follows: surface

[0172] Once the fid is acquired and the Fourier transform is completed, the phase of the frequency domain spectrum is manually corrected (.ph), followed by apodization-Fourier transform-automatic phase correction (EFP), and finally baseline correction (ABS). The spectrum is calibrated using the sharp peak at 132.20 ppm of the reaction byproduct of the phosphorylation reagent with water. First, the cholesterol peak (144.8 ppm) is integrated between 145.0 and 144.4 ppm and calibrated to 1. Then, other signals are integrated as follows: Table 5

[0173] The concentration of each OH group (mmol OH / g sample) was determined using the following formula: Functional group OH group (mmol) / g sample =

[0174] C: Internal standard concentration (mg / mL)

[0175] A: Area of ​​the OH functional group (when the integral calibration of the cholesterol peak is 1).

[0176] IS: Volume of pyridine internal standard solution added (0.1 mL)

[0177] M: Internal standard molecular weight (386.65 g / mol)

[0178] L: Weight (g) of the freeze-dried sample added to the vial

[0179] P: Internal standard purity (0.99)

[0180] The mass of the -COOH functional group on the lignin polymer can then be calculated using the molecular weight of the -COOH functional group (45.0174 g / mol), and the weight can be calculated based on the total weight of the oxidized sulfonated lignin.

[0181] Appendix 1

[0182] HSP Introduction

[0183] Hansen's solubility parameter (HSP) explains why a solvent can dissolve nail polish, viscous spruce resin, or rubber glue. The solvent's HSP is similar to the HSP of the substance being dissolved; in other words, "..." Like dissolves like Here is a lighthearted and humorous YouTube video about this principle: (Limonene in lemons is very similar to isoprene rubber in party balloons.)

[0184] If the HSPs are not close, such as water with respect to these same materials, then the "solvent" is not a good solvent. There are three numbers together called the HSP. If its HSP is known or can be estimated, these numbers can comprehensively describe the behavior of that solvent relative to many other substances. Common substances like sugar, butter, and even aspirin, phthalates, drugs, and DNA have HSPs. The HSP describes how well substances tend to approach each other. For example, water won't wet many surfaces because its HSPs are too different, but it can dissolve sugars (to a large extent) because its HSPs are close enough (but not a perfect match).

[0185] In practice, solvents are represented as points in three-dimensional space (called HSP space). This is because three parameters (δD, δP, and δH) are needed to describe their tendency or inclination to occupy a particular position. Substances they dissolve or tend to coexist with have similar HSPs. However, it has been found that complete dissolution does not require perfectly matching HSPs. If many solvents are tested to determine whether they are good or bad solvents for viscous spruce resin, it can be found that good solvents aggregate in the three-dimensional HSP space, forming a sphere centered on the HSP of that viscous spruce resin. The characteristic differences in HSPs present in all three parameters allow for good compatibility. These determine the radius of the sphere. Good solvents reside inside the sphere, while bad solvents reside outside.

[0186] Such spheres have been tested on hundreds of different substances. In many cases, their effectiveness has been validated by accurate predictions that when two non-solvent HSPs are located on opposite sides of an HSP sphere, mixing these two solvents will dissolve a certain material. The HSP of the mixture depends directly on the relative amounts present, and even if a single solvent is not a good solvent, the mixture will predictably exhibit "good solvent" properties. This synergistic mixture is of great practical significance and has been used to replace undesirable solvents, reduce costs, and simultaneously improve performance.

[0187] The HSP correlation for rapid skin penetration of solvents is represented by green spheres (large spheres). Dioctyl phthalate (DOP) is represented by small spheres on the left, and ethanol by small spheres on the right. A 50 / 50 mixture will make DOP more easily penetrate the skin. This is because the HSP of the mixture is additive based on the individual volume fractions of its components, and in this case, the mixture will be closer to the HSP of the green (large) spheres.

[0188]

[0189] What may be surprising is that HSPs can be assigned to so many different substances. Gases such as carbon dioxide, solids such as C-60 and sugars, and biomaterials such as human skin, body fat, DNA, and even certain proteins all possess HSPs. The list can continue to expand to pharmaceuticals, polymers, plasticizers, and virtually any organic material, even many inorganic materials such as salts. The only requirement for experimental confirmation is that the material must behave differently when exposed to a sufficient quantity of the test solvent. “Good” and “poor” solvents must be identified. The definition of “good” can range from swelling to complete dissolution, from the difference between prolonged suspension and rapid sedimentation of particles (pigments, fibers), to the difference between rapidly penetrating protective gloves and good protection (i.e., no penetration). All these tests have been used for HSP assignment. Once an HSP is known, products can be systematically designed to meet given requirements, or experiments can be interpreted to find the causes of various phenomena, even under complex conditions. The predictive power is extremely strong, and the understanding provided is satisfying for those seeking to know the reasons behind them.

[0190] In the past, applying these simple concepts was surprisingly difficult. However, with the extensive interpretation of HSPs and the wealth of data on solvents and other materials provided in a useful format, things have become much easier. Sufficient information allows for reasonable predictions solely through computers, and the HSPs of new or untested materials and combinations can be estimated, enabling the investigation of what they can and cannot do. While these predictions are not as reliable as experimental verification, they allow for the screening of promising candidates from the unpromising. This selection of candidates can save significant time and money.

[0191] For those who wish to gain a more comprehensive understanding, further details regarding the scientific background of HSPs can be found on the website. But in short, an HSP tells the user where something tends to lie. This is where HSPs are reasonably similar to themselves. This can lead to swelling and / or complete dissolution, wetting and / or adsorption, osmosis, or other related phenomena.

[0192] Appendix 2

[0193] HSP sphere

[0194] HSP is measured using a sphere technique. A set of solvents with known HSPs is used to test the "happiness" of the test material in those solvents. A sphere is then constructed such that all "good" solvents are inside the sphere, and all "poor" solvents are outside. The center of the sphere represents the HSP of the test material, while the radius defines the limits of its "happiness" when searching for other solvent systems with which it can be used.

[0195] If the test material is a simple polymer or crystalline solute, then we will use the term "solubility" instead of "compatibility." However, the technique is entirely generic, and the definition of "compatibility" is variable. For nanoparticles and dispersions, the definition could be "maintaining good suspension." For cross-linked polymers, the definition could be "significant swelling." The key is that the formulation engineer clearly defines their specific requirements for a "compatible" formulation, and therefore can choose their own definition so that the measured HSP and radius are meaningful for a given application.

[0196] Here we show a class of solubility spheres for polylactic acid (PLA). The center of the sphere is a reasonable estimate of the central HSP of PLA. The radius is quite large because the particular PLA has a medium molecular weight and crystallinity. In other (unpublished) works, we used highly crystalline PLA, which gives the same central HSP but a much smaller radius. All good solvents (blue) are inside the spheres (transparent green), all poor solvents (red) are outside the spheres, and PLA itself is the green dot in the center.

[0197]

Claims

1. A composition for preparing a positive or negative electrode of a lithium-ion battery or a sodium-ion battery, said composition comprising: (a) A lignin derivative present in a dry matter weight of 0.01% to 4.0% by weight, based on the total weight of the composition. (b) at least one active material, and (c) Solvent.

2. The composition of claim 1, wherein the composition is a composition for preparing a positive electrode for a lithium-ion battery or a sodium-ion battery.

3. The composition of claim 1 or 2, wherein the solvent is water or contains water, preferably water.

4. The composition as described in any one of the preceding claims, characterized in that... The composition does not contain N-methylpyrrolidone (NMP).

5. The composition of any one of the preceding claims, wherein the lignin derivative is sulfonated lignin, carboxylated lignin, hydrolyzed carboxylated lignin, or amine-functionalized lignin.

6. The composition of any one of the preceding claims, wherein the lignin derivative is sulfonated lignin.

7. The composition of claim 6, wherein the sulfonated lignin is lignin sulfonate or sulfonated kraft paper lignin, preferably lignin sulfonate.

8. The composition as claimed in any of the preceding claims, wherein the lignin derivative is present, based on the total weight of the composition, in a dry matter weight of 0.01 wt% to 3.5 wt%, preferably 0.01 wt% to 3.0 wt%, more preferably 0.01 wt% to 2.5 wt%, more preferably 0.01 wt% to 2.0 wt%, more preferably 0.05 wt% to 1.5 wt%, more preferably 0.05 wt% to 1.0 wt%, more preferably 0.05 wt% to 0.8 wt%, more preferably 0.05 wt% to 0.7 wt%, more preferably 0.07 wt% to 0.7 wt%, 0.07 wt% to 0.6 wt%, more preferably 0.07 wt% to 0.6 wt%, more preferably 0.08 wt% to 0.4 wt%, more preferably 0.1 wt% to 0.3 wt%.

9. Use of lignin derivatives as dispersants in compositions used to prepare positive or negative electrodes, preferably positive electrodes, for lithium-ion or sodium-ion batteries.

10. Use of lignin derivatives to reduce the shear rate of compositions used in the preparation of positive or negative electrodes for lithium-ion or sodium-ion batteries, preferably positive electrodes.

11. The use as described in claim 9 or 10, wherein the composition is an electrode paste, preferably a positive electrode paste.

12. A positive or negative electrode for lithium-ion or sodium-ion batteries, preferably a positive electrode, characterized in that... It is prepared from the composition described in claims 1 to 8.

13. A lithium-ion battery or a sodium-ion battery, preferably a lithium-ion battery, characterized in that... It comprises the electrode as described in claim 12, preferably a positive electrode.

14. A method for preparing a positive or negative electrode, preferably a positive electrode, for a lithium-ion battery or a sodium-ion battery, the method comprising the following steps: (1) Apply the composition of any one of claims 1 to 8 to a substrate. (2) Dry the composition.

15. The method of claim 14, further comprising step (3) compressing the product obtained in step (2) using a calendering process.

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