Dispersing agent, electrode material, electrode plate and battery

Abstract

The invention discloses a dispersing agent, an electrode material, an electrode plate and a battery. The dispersing agent comprises a three-dimensional covalent organic framework and a polar organic matter, and the polar organic matter can be connected with the three-dimensional covalent organic framework through polar groups contained in the polar organic matter. After the dispersing agent is compounded through the three-dimensional covalent organic framework and the polar organic matter, the dispersing agent can achieve a steric hindrance synergistic effect and a charge repulsive effect on particles including an electrode active material, a conductive agent and the like in the electrode slurry, so that the dispersity and the stability of the electrode slurry are improved; and meanwhile, a three-dimensional ion conductive network structure can be formed in an active material layer formed by the electrode slurry. Any one of the electrode material, the electrode plate and the battery contains the dispersant.

Description

Technical Field

[0001] The present application belongs to the field of batteries, and specifically relates to a dispersant, an electrode material, an electrode sheet and a battery. Background Art

[0002] With the rapid development of mobile electronic devices, electric vehicles and renewable energy, batteries such as lithium-ion batteries, as key energy storage devices, have increasingly higher performance requirements. Among them, high energy density and cycle performance are important performance indicators of batteries, and the energy density and cycle performance of batteries are closely related to the uniform distribution of electrode active materials in the active material layer in the pole piece, the quality of the film layer and the structural stability.

[0003] However, in actual operation, due to the high surface energy of electrode active materials such as positive electrode materials, agglomeration is easy to occur during the slurry preparation process, resulting in problems such as uneven slurry and high viscosity, which in turn leads to uneven distribution of electrode active materials in the active material, poor quality of the formed film layer, easy pulverization and other adverse consequences, which in turn leads to unsatisfactory battery performance such as energy density and cycle performance.

[0004] In view of the above problems, the commonly used solution is to add dispersants to the slurry to reduce the agglomeration of the electrode active materials, thereby improving the dispersibility of the electrode active materials and the uniformity of the slurry, thereby improving the quality of the electrode sheets. However, although the existing dispersants can improve the dispersibility of the electrode slurry to a certain extent, as the market has higher and higher requirements for battery energy density and cycle performance, the existing dispersants cannot meet the current needs. Summary of the invention

[0005] The purpose of the present application is to overcome the above-mentioned deficiencies of the prior art and to provide a dispersant, an electrode sheet and a battery to solve the technical problem that the existing dispersant has unsatisfactory dispersibility in improving the dispersibility of the electrode slurry.

[0006] In order to achieve the above application purpose, in the first aspect, the present application provides a dispersant. The dispersant of the present application comprises a three-dimensional covalent organic skeleton, a polar organic substance and a flexibilizer, wherein the polar organic substance contains a polar group, and the polar organic substance can be connected to the three-dimensional covalent organic skeleton through the polar group.

[0007] The dispersant of the present application is compounded by a three-dimensional covalent organic skeleton and a polar organic matter, so that the two can play a steric hindrance synergistic role and charge repulsion effect on particles including electrode materials, conductive agents, etc. in the electrode slurry, reduce the agglomeration of electrode materials and conductive agents, and improve the dispersibility, stability and solid content of the electrode slurry; at the same time, a three-dimensional ion conductive network structure can be formed in the active material layer formed by the electrode slurry, thereby improving the ionic conductivity of the active material layer.

[0008] In a second aspect of the present application, an electrode material is provided. The electrode material of the present application includes a positive electrode active material or a negative electrode active material, or a mixture of a positive electrode active material or a negative electrode active material and a lithium supplement, and also includes a dispersant, and the dispersant includes the dispersant of the present application.

[0009] When the electrode material of the present application is prepared into an electrode slurry, the building blocks contained in the three-dimensional covalent organic skeleton contained in the dispersant have a large volume and a three-dimensional spatial structure, so that the three-dimensional covalent organic skeleton can play a steric hindrance role, hindering the electrode slurry, including the electrode material, the conductive agent and other component particles from approaching each other, thereby reducing the occurrence of agglomeration. The polar organic matter contained in the dispersant can effectively bind to the surface of the component particles including the electrode material, the conductive agent and the like, so that the component particles including the electrode material, the conductive agent and the like are polar and produce a charge discharge effect between two adjacent particles, thereby reducing the occurrence of agglomeration of each particle; and the polar organic matter can also interact with the three-dimensional covalent organic skeleton, thereby playing a steric hindrance synergistic role, further hindering the particles in the electrode slurry from approaching each other to reduce the occurrence of agglomeration, improving the dispersibility and stability of the electrode slurry, and at the same time can also reduce the viscosity of the electrode slurry and increase the solid content of the electrode slurry.

[0010] In a third aspect of the present application, an electrode sheet is provided. The electrode sheet of the present application comprises a current collector and an active material layer disposed on at least one surface of the current collector, wherein the active material layer comprises the electrode material of the present application.

[0011] The electrode sheet of the present application contains the electrode material of the above-mentioned application. Therefore, the electrode material, conductive agent and other components in the active material layer of the electrode sheet of the present application are evenly dispersed, which improves the membrane surface density and capacity density as well as the cycle performance. At the same time, a three-dimensional ion conductive network structure can also be formed in the active material layer, and its ion conductivity is high.

[0012] In a fourth aspect of the present application, a battery is provided. The battery of the present application comprises a positive electrode sheet and a negative electrode sheet, wherein the positive electrode sheet is the electrode sheet of the present application, and the electrode material contained in the electrode sheet comprises a positive electrode active material; and / or

[0013] The negative electrode sheet is the electrode sheet of the present application, and the electrode material contained in the electrode sheet includes a negative electrode active material.

[0014] Since at least one of the positive electrode sheet and the negative electrode sheet in the battery of the present application is the electrode sheet of the above-mentioned application, the electrode material contained in the electrode sheet of the battery of the present application is evenly distributed in the active material layer, and the electrode sheet has a high capacity density and structural stability, thereby giving the battery a high energy density and cycle performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 Schematic diagram of the connection between the three-dimensional covalent organic skeleton and the polar organic matter contained in the dispersant of the embodiment of the present application in the electrode slurry;

[0017] Figure 2 It is a schematic diagram of the connection between the three-dimensional covalent organic skeleton and the polar organic matter contained in the dispersant of the embodiment of the present application in the electrode slurry, and between the three-dimensional covalent organic skeleton, the polar organic matter and the particles of the electrode active material, the conductive agent, etc. DETAILED DESCRIPTION

[0018] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0019] In this application, the term "and / or" describes the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural. The character " / " generally indicates that the associated objects are in an "or" relationship.

[0020] In this application, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, c can be single or multiple, respectively.

[0021] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution, some or all of the steps can be executed in parallel or sequentially, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0022] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0023] The weight of the relevant components mentioned in the embodiment description of the present application can not only refer to the specific content of each component, but also represent the proportional relationship between the weights of the components. Therefore, as long as the content of the relevant components is proportionally enlarged or reduced according to the embodiment description of the present application, it is within the scope disclosed in the embodiment description of the present application. Specifically, the mass described in the embodiment description of the present application can be a mass unit known in the chemical industry such as μg, mg, g, kg, etc.

[0024] The terms "first" and "second" are used only for descriptive purposes to distinguish objects such as substances from each other, and should not be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. For example, without departing from the scope of the embodiments of the present application, the first XX may also be referred to as the second XX, and similarly, the second XX may also be referred to as the first XX. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0025] As the market places higher and higher demands on battery safety, energy density, and service life, higher and higher requirements are currently being placed on the performance of pole pieces, including capacity density, structural stability, and cyclability. However, electrode active materials, such as positive electrode active materials, have characteristics such as easy agglomeration, which causes the electrode slurry to be uneven and have high viscosity due to the agglomeration of the electrode active materials when preparing the electrode slurry, resulting in poor uniformity of the formed active material layer, and easily causing defects such as cracking and powder loss in the active material layer. Furthermore, it has been found in actual applications that the mechanical properties of existing pole pieces, such as peel strength, are difficult to meet the application requirements of current batteries. These deficiencies of pole pieces will directly affect the battery's energy density, cycle performance, safety, and other performance.

[0026] In order to effectively improve the dispersion uniformity and peel strength of the electrode slurry, so as to improve the energy density, cycle performance, safety and other performance of the battery, the following technical solutions are proposed in the embodiments of the present application.

[0027] [Dispersant]

[0028] In the first aspect, the present application provides a dispersant. The dispersant of the present application comprises a three-dimensional covalent organic skeleton, a polar organic substance and a flexibilizer. The polar organic substance contains polar groups, and the polar organic substance can be connected to the three-dimensional covalent organic skeleton through the polar groups contained therein.

[0029] In the dispersant of the present application, the three-dimensional covalent organic skeleton refers to a class of organic substances that contain covalent bonds and have a three-dimensional network structure connected by covalent bonds. Polar organic substances refer to organic substances with polar bonds in the molecules, and the polar functional groups contained refer to groups with non-coincident positive and negative charge centers or groups with a dipole moment generally greater than 0.5.

[0030] The three-dimensional covalent organic skeleton contained in the dispersant of the embodiment of the present application has a large volume and a three-dimensional spatial structure, and these building blocks will produce a repulsive effect when they are interconnected in space, which plays a steric hindrance. At the same time, the three-dimensional covalent organic skeleton generally also contains a functional group, which, together with the building block, can play a synergistic role in the steric hindrance. In addition, the three-dimensional covalent organic skeleton has good ionic conductivity and can form a three-dimensional ionic conductive network in the dispersed object. Therefore, the three-dimensional covalent organic skeleton can play a steric hindrance effect on the dispersed object such as electrode active materials, conductive agents, etc., and can hinder the dispersed objects from contacting each other and agglomerating, thereby improving the dispersibility of the dispersed object, and at the same time forming a three-dimensional ionic conductive network structure in the dispersed object to improve ionic conductivity.

[0031] The polar groups contained in the polar organic matter can provide lone pairs of electrons and can be adsorbed on the surface of the dispersed matter, making the dispersed matter polar, thereby enhancing the charge repulsion between the dispersed matter, thereby improving the dispersibility of the dispersed matter. In addition, the polar organic matter can also be connected to the three-dimensional covalent organic skeleton through the polar groups it contains, so that the polar organic matter and the three-dimensional covalent organic skeleton can play a steric hindrance synergistic role, further hindering the agglomeration of the dispersed matter, and further improving the dispersibility of the dispersed matter. Specifically, Figure 1 As shown, the polar organic matter 2 can also be connected to the three-dimensional covalent organic skeleton 1 through the polar groups it contains. After the two are connected, the internal groups in the molecules repel each other in space, thereby further enhancing the steric hindrance effect.

[0032] Therefore, after the dispersant of the embodiment of the present application is compounded with a three-dimensional covalent organic skeleton and a polar organic matter, the two can play a steric hindrance synergistic role and a charge repulsion role on the dispersed material, reduce the agglomeration phenomenon of the dispersed material, and improve the dispersibility of the dispersed material; at the same time, a three-dimensional ion conductive network structure can be formed between the dispersed materials, thereby improving the ionic conductivity of components formed by the dispersed materials, such as membrane layers.

[0033] In this way, when the dispersant of the embodiment of the present application is used as a dispersant to prepare the electrode slurry, the three-dimensional covalent organic skeleton contained therein can itself play a steric hindrance role in the electrode slurry, hindering the aggregation of particle components such as electrode active materials and conductive agents and uniformly dispersing them in the electrode slurry. Polar organic matter can combine with the surface of particles of electrode active materials, conductive agents, etc. through the polar groups contained therein, enhance the polarity of particles of electrode active materials, conductive agents, etc., improve the charge repulsion between particles of electrode active materials, conductive agents, etc., and improve the dispersibility of particles of electrode active materials, conductive agents, etc. Moreover, polar organic matter can combine with the three-dimensional covalent organic skeleton through the polar groups contained therein, so that the two can play a synergistic role in the steric hindrance of particles of electrode active materials, conductive agents, etc., so that the combined effect of steric hindrance and charge repulsion can improve the dispersibility of particles of electrode active materials, conductive agents, etc., thereby improving the dispersibility and stability of the electrode slurry, and at the same time can increase the viscosity of the electrode slurry, thereby increasing the solid content of the electrode slurry. Specifically, Figure 2 As shown, in the electrode slurry, part of the polar organic matter 2 can be combined with the surface of the electrode active material, conductive agent and other particles 3 through the polar groups contained therein; part of the polar organic matter 2 can be combined with the three-dimensional covalent organic skeleton 1 through the polar groups contained therein. At this time, the polar organic matter 2 acts as a connecting bridge between the three-dimensional covalent organic skeleton 1 and the electrode active material, conductive agent and other particles 3. As a result, the uniformity of the distribution of the electrode active material in the active material layer formed by the electrode slurry and the quality of the film layer can be improved, and the capacity and cycle performance and capacity density of the electrode sheet can be improved. In addition, since the three-dimensional covalent organic skeleton has good ionic conductivity, it can form a three-dimensional ionic conductive network structure in the active material layer formed together with the conductive agent in the electrode slurry, thereby improving the ionic conductivity of the electrode sheet and the conductivity of the active ions.

[0034] In some embodiments, the mass ratio of the three-dimensional covalent organic framework and the polar organic matter can be (5-30): (10-50), further (10-20): (20-30). In the exemplary embodiments, the mass ratios of 5:10, 5:20, 5:30, 5:40, 5:50, 10:10, 10:20, 10:30, 10:40, 10:50, 20:10, 30:10, 30:20, 30:40, 30:50 are typical but non-limiting mass ratios or the range between any two mass ratios. The mass ratio of the two in this range can further enhance the steric hindrance synergistic effect between the two on the dispersed substances such as electrode active materials and conductive agents, and further improve the charge repulsion effect on the dispersed substances, thereby further improving the dispersibility of the dispersed substances such as electrode slurry, thereby further improving the uniformity of the distribution of electrode active materials and conductive agents in the active material layer formed by the electrode slurry, improving the film quality, and improving the energy density and cycle performance of the electrode sheet. At the same time, it can improve the three-dimensional ion conductive network structure in the active material layer formed by the electrode slurry and improve the conductivity of the electrode sheet.

[0035] Three-dimensional covalent organic frameworks:

[0036] In some embodiments, the three-dimensional covalent organic skeleton may include at least one of a small molecule three-dimensional organic skeleton and a polymer three-dimensional organic skeleton. These small molecule three-dimensional organic skeletons and polymer three-dimensional organic skeletons have rich three-dimensional covalent structures, which can play a steric hindrance role on the dispersed material, such as in the electrode slurry, and improve the dispersion effect on the dispersed material, such as improving the dispersibility and dispersion stability of the electrode slurry.

[0037] In an embodiment, when the three-dimensional covalent organic framework includes a small molecule three-dimensional organic framework, the small molecule three-dimensional organic framework may be at least one of adamantane small molecules, cyclic hydrocarbon small molecules, tetrahedral structure small molecules, cubane small molecules, and prismane small molecules.

[0038] In an embodiment, when the three-dimensional covalent organic skeleton includes a polymer three-dimensional organic skeleton, the polymer three-dimensional organic skeleton may include at least one of adamantane polymers, cyclic hydrocarbon polymers, tetrahedral polymers, cubanes, and prismane polymers.

[0039] The molecules of the above-mentioned small molecule three-dimensional organic skeletons and polymer three-dimensional covalent organic skeletons have three-dimensional structure, low crosslinking, high specific surface area and large pore size characteristics, which can improve the steric hindrance effect in the electrode slurry, thereby further reducing the agglomeration of particles such as electrode active materials and conductive agents, thereby improving the dispersibility and dispersion stability of the electrode slurry. Among them, relative to the small molecule three-dimensional organic skeleton, the polymer three-dimensional covalent organic skeleton has a relatively larger three-dimensional structure, high specific surface area and large pore size characteristics, and the steric hindrance effect is stronger. Therefore, based on the steric hindrance effect played in the electrode slurry, the polymer three-dimensional organic skeleton is preferred relative to the small molecule three-dimensional organic skeleton.

[0040] In an exemplary embodiment, when the above-mentioned small molecule three-dimensional organic skeleton may include adamantane compounds, the adamantane compounds may include at least one of bis-adamantane, substituted bis-adamantane, triamantane, substituted triamantane, tetraamantane, substituted tetraamantane, pentamantane, substituted pentamantane, and small molecule adamantane derivatives. Wherein, the structural formula of bis-adamantane is shown in Formula 1, the structural formula of triamantane is shown in Formula 2, the structural formula of tetraamantane is shown in Formula 3, and the structural formula of pentamantane is shown in Formula 4. The substituted bis-adamantane may be a substituent of the bis-adamantane substitutable position shown in Formula 1, the substituted triamantane may be a substituent of the triamantane substitutable position shown in Formula 2, the substituted tetraamantane may be a substituent of the tetraamantane substitutable position shown in Formula 3, and the substituted pentamantane may be a substituent of the pentamantane substitutable position shown in Formula 2. In the exemplary embodiments, the substituent groups of the substituents may be at least one of hydrocarbon groups (alkyl, alkenyl, alkynyl, aryl, etc.), oxygen-containing functional groups (hydroxyl (-OH), aldehyde (-CHO), carbonyl (-C=O), carboxyl (-COOH), ester (-COOR), ether bond (-O-)), nitrogen-containing functional groups (amino (-NH2), amide (-CONH2), amine (-NR2, where R may be hydrogen or a hydrocarbon group)), etc.

[0041]

[0042] In an exemplary embodiment, the small molecule adamantane derivative may include at least one of 1,3,5,7-tetrakis(4-benzaldehyde)-adamantane (TFPA), 1,3,5,7-tetrakis(4-methoxycarbonylphenyl)-adamantane, 1,3,5,7-tetrakis(3-benzaldehyde)-adamantane, 1,3,5,7-tetrakis(4-(N,N-dimethylamino)phenyl)-adamantane, and 1,3,5,7-tetrakis(4-(2-benzaldehydeethyl))-adamantane.

[0043] In an exemplary embodiment, the cyclic hydrocarbon small molecules may include at least one of benzene ring-containing aromatic compounds, cyclooctane, cyclopentane, and cyclohexane.

[0044] In an exemplary embodiment, the tetrahedral structured small molecule may include at least one of the following formula 5 (2,2′,7,7′-tetramethoxy-9,9′-spirobifluorene-3,3′,6,6′-tetracarboxaldehyde) and its derivatives.

[0045]

[0046] In an exemplary embodiment, the adamantane polymer described above may include at least one of the following structural formula 6 and its derivatives.

[0047]

[0048] In an exemplary embodiment, when the adamantane polymer is a structural formula 6, the structural formula 6 may be a compound generated by a condensation reaction of 1,3,5,7-tetrakis(4-benzaldehyde)-adamantane (TFPA) and 2,6-diaminonaphthalene (DAN). In an embodiment, the condensation reaction of TFPA and DAN may include the following steps:

[0049] The condensation reaction is carried out with TFPA and DAN in a solution containing a catalyst.

[0050] The chemical reaction formula of the condensation reaction of TFPA and DAN is shown in the following reaction formula (1):

[0051]

[0052] In the condensation reaction shown in the chemical reaction formula (1), the formaldehyde group in TFPA reacts with the amino group (-NH2) in DAN to form the corresponding enamine (or imine). In the embodiment, the molar ratio of TFPA and DAN can be 1: (0.5-5), and in the exemplary embodiment, it can be but not limited to a molar ratio of 1: 2; the catalyst can include but not limited to acetic acid (acetic acid); the reaction solvent can include a polar solvent, such as including but not limited to dioxane; the temperature of the condensation reaction can be 100-150°C, such as but not limited to 120°C, and the reaction time is sufficient, such as but not limited to 3 days.

[0053] In an exemplary embodiment, the cyclic hydrocarbon polymer may include at least one of a benzene ring-containing polymer, a cyclooctane polymer, a cyclopentane polymer, and a cyclohexane polymer.

[0054] In an exemplary embodiment, the tetrahedral structure (2,2′,7,7′-tetramethoxy-9,9′-spirobifluorene-3,3′,6,6′-tetracarboxaldehyde) type polymer described above may include at least one of the substances generated by the reaction of 2,2′,7,7′-tetramethoxy-9,9′-spirobifluorene-3,3′,6,6′-tetracarboxaldehyde with 1,8-diaminonaphthalene and its derivatives.

[0055] The three-dimensional covalent organic framework compounds of the above-mentioned small molecule three-dimensional organic framework and polymer three-dimensional organic framework have a large volume and three-dimensional spatial structure, and have a relatively strong steric hindrance. Moreover, some of these compounds also contain functional groups, which together with the building blocks in the molecular structure formula can play a synergistic role in the steric hindrance. In addition, these compounds have good ionic conductivity and can form a three-dimensional ionic conductive network in the dispersed object.

[0056] Regardless of whether the three-dimensional covalent organic skeleton contained in the dispersant of the embodiment of the present application is the above-mentioned small molecule three-dimensional organic skeleton or the polymer three-dimensional organic skeleton, in some embodiments, the particles of the three-dimensional covalent organic skeleton of each embodiment above also have characteristics such as large specific surface area, large pore size and porous structure. It is known through experiments that the three-dimensional covalent organic skeleton with characteristics such as large specific surface area, large pore size and porous structure has relatively excellent steric hindrance. Among them, the particles of the three-dimensional covalent organic skeleton can refer to particles when the three-dimensional covalent organic skeleton is in a solid state, such as particles in the active material layer of the pole piece when it is in a solid state.

[0057] As shown in the embodiment, the specific surface area of ​​the three-dimensional covalent organic framework particles is 100 to 2000 m 2 / g, optional range is 200~800m 2 / g.

[0058] In the embodiment, the pore size of the particles of the three-dimensional covalent organic framework is 1 nm to 500 nm, and can be optionally 5 nm to 20 nm.

[0059] In an embodiment, the porosity of the three-dimensional covalent organic framework particles is 20% to 80%, and can be optionally 30% to 50%.

[0060] The three-dimensional covalent organic skeleton with particles having the above-mentioned specific surface area, pore size and porosity range can further exert a steric hindrance effect in the electrode slurry, and can further combine with polar organic matter to enhance the synergistic effect of steric hindrance, thereby further improving the dispersibility and stability of the electrode slurry.

[0061] Polar organic matter:

[0062] In some embodiments, the polar groups contained in the polar organic matter include at least one of amino, hydroxyl, alkoxy, carboxyl, amide, sulfonic acid, phosphoric acid, and nitro. These polar groups have relatively strong polarity and can effectively bind to the surface of dispersed objects such as electrode active materials and conductive agents, so that the dispersed objects such as electrode active materials and conductive agents in the electrode slurry have polarity, thereby generating charge repulsion between adjacent particles, reducing agglomeration, and improving the dispersibility and dispersion stability of dispersed objects such as electrode active materials and conductive agents in the electrode slurry.

[0063] In the embodiment, when the polar group contained in the polar organic matter includes an amino group, the polar organic matter containing the amino group may include at least one of aliphatic amine, isopropanolamine, o-aminophenol, m-aminophenol, and p-aminophenol, wherein the aliphatic amine may include but is not limited to at least one of ethylenediamine, diethylamine, and triethylamine; when the polar group contained in the polar organic matter includes a hydroxyl group, the polar organic matter containing the hydroxyl group may include at least one of phenol, lactic acid, glucose, glycerol, and ethylene glycol; when the polar group contained in the polar organic matter includes a carboxyl group, the polar organic matter containing the carboxyl group may include at least one of cinnamic acid derivatives and benzoic acid derivatives, wherein the cinnamic acid derivatives may include but are not limited to at least one of ferulic acid, caffeic acid, etc., and the benzoic acid derivatives include but are not limited to 3,4-dihydroxybenzoic acid. These polar organic matters are rich in polar groups, can effectively bind to the surface of particles such as electrode active materials and conductive agents in the dispersed matter such as electrode slurry and make the dispersed matter present polarity, and improve the dispersibility and dispersion stability of the dispersed matter such as electrode active materials and conductive agents in the electrode slurry. At the same time, these organic substances can also be connected to the three-dimensional covalent organic skeleton mentioned above, such as through polar groups, so that these polar organic substances and the three-dimensional covalent organic skeleton play a steric hindrance role, further hindering the agglomeration of the dispersed substances and further improving the dispersibility of the dispersed substances.

[0064] In some embodiments, on the basis of the above embodiments, the dispersant of the embodiments of the present application may further include at least one component selected from the group consisting of a solvent and a softener. Among them, a softener refers to an auxiliary agent that can improve the flexibility of components such as film layers formed by the dispersed material. When the dispersant of the embodiments of the present application contains a softener, the softener can play a softening role, can reduce the rigidity of components such as film layers formed by the dispersed material, improve the elasticity and toughness of the components, and reduce the cracking of the components. Specifically, it can reduce the elasticity and toughness of the active material layer contained in the pole piece, improve the structural stability of the active material layer, and reduce the occurrence of undesirable phenomena such as cracking and pulverization. At the same time, the softener can play a steric hindrance role under the action of the polar groups of the polar organic matter, thereby improving the dispersibility of the dispersed material such as the electrode slurry.

[0065] In the embodiment, when the dispersant of the above text application embodiment contains a solvent, the solvent acts as a solvent carrier, and the dispersant of the embodiment of the present application, such as the above three-dimensional covalent organic skeleton, polar organic matter, or further includes a softener, is dissolved in the solvent, and each component is dissolved in the solvent, so that each component is uniformly dispersed in the solvent, and the polar groups of the polar organic matter can also act on the three-dimensional covalent organic skeleton or further softener molecules, such as connecting at least one molecule of the three-dimensional covalent organic skeleton and the softener molecule, thereby increasing the steric hindrance characteristics of the dispersant of the embodiment of the present application, thereby effectively enhancing the steric hindrance effect on components including electrode active materials, conductive agents, etc. in the electrode slurry, improving the dispersibility of components such as electrode active materials and conductive agents, thereby improving the dispersibility and stability of the electrode slurry.

[0066] In the embodiment, when the dispersant of the embodiment of the present application contains a solvent, the content of the solvent can make the mass concentration of the above three-dimensional covalent organic framework in the dispersant be 1% to 40%, optionally 2% to 40%, and further 5% to 10%. In the exemplary embodiment, it can be 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40% and other typical but non-limiting concentrations or a range between any two concentration values. The concentration range of the three-dimensional covalent organic framework can make the three-dimensional covalent organic framework, polar organic matter, or further include components such as a softener fully dissolved in the solvent, giving full play to the synergistic effect between each component and each component.

[0067] In an embodiment, the solvent can be a solvent that can effectively dissolve the three-dimensional covalent organic framework containing polar organic matter and the flexibilizer. For example, in an exemplary embodiment, the solvent can include at least one of N-methylpyrrolidone (NMP), dimethyl sulfoxide, dimethylformamide, etc. These types of solvents can effectively dissolve the three-dimensional covalent organic framework, polar organic matter and flexibilizer, and can improve the stability of each component.

[0068] In the embodiment, when the dispersant of the above application embodiment contains a softener, the mass ratio of the three-dimensional covalent organic framework to the softener can be (10-50): (5-30), optionally (10-30): (10-20), in the exemplary embodiment, the mass ratio of 10:5, 20:5, 30:5, 40:5, 50:5, 10:10, 20:10, 30:10, 40:5, 50:10, 30:20, 40:20, 50:20 and other typical but non-limiting mass ratios or the range between any two mass ratios. The mass ratio of the two in this range can further improve the elasticity and toughness of the active material layer in the pole piece, and improve the structural stability and cycle performance of the pole piece.

[0069] In the embodiment, when the dispersant in the above text application embodiment contains a softener, the softener mainly includes a flexible resin softener. In the exemplary embodiment, the flexible resin includes at least one of flexible resin CAP resin (cellulose ethane propionate), ABS resin (acrylonitrile-butadiene-styrene terpolymer), polyacrylic resin, 203 resin (octylphenol formaldehyde tackifying resin), epoxy resin, and MBS resin (methyl methacrylate, butadiene, styrene terpolymer). These softeners can play a softening role, can improve the elasticity and toughness of the pole piece and the peel strength, and reduce the cracking of the pole piece. At the same time, the softener can play a steric hindrance role together with components such as the three-dimensional covalent organic skeleton under the action of the polar groups of the polar organic matter, thereby improving the dispersibility and dispersion stability of the electrode slurry.

[0070] In addition, the dispersant of the present application embodiment can be compounded according to the types and contents of the components contained in the above dispersant, such as physically mixing the raw materials of each component. When a solvent is contained, the other components contained in the above dispersant can be added to the solvent for dissolution, so that the components are evenly mixed to form a uniformly dispersed and stable mixed solution.

[0071] [Electrode materials]

[0072] In a second aspect, the present application also provides an electrode material. The electrode material of the present application includes a positive electrode active material or a negative electrode active material, or a mixture of a positive electrode active material or a negative electrode active material and a lithium supplement, and also includes a dispersant, and the dispersant includes the dispersant of the above-mentioned application embodiment.

[0073] In the electrode material of the embodiment of the present application, the dispersant contained therein may form a physical mixture with the positive electrode active material or the negative electrode active material or further with components such as a lithium supplement. Of course, it may also be provided separately from these components, and mixed during the preparation of the electrode slurry. When the dispersant contained in the electrode material of the embodiment of the present application forms a physical mixture with the positive electrode active material or the negative electrode active material or further with components such as a lithium supplement, the polar organic matter contained in the dispersant of the above embodiment of the present application is at least partially bound to the surface of the particles of the positive electrode active material or the negative electrode active material or further with components such as a lithium supplement. At the same time, at least part of the polar organic matter is connected to the surfaces of these component particles while connecting to the three-dimensional covalent organic skeleton contained in the dispersant of the above embodiment of the present application. At this time, the polar organic matter plays a bridging role between these component particles and the three-dimensional covalent organic skeleton, such as Figure 1 In the embodiment, when the dispersant in the above embodiment of the application contains a solvent, the electrode material in the embodiment of the present application can be a slurry.

[0074] Since the electrode material of the embodiment of the present application contains the dispersant of the embodiment of the present application, when the electrode material of the present application is prepared into the electrode slurry, the three-dimensional covalent organic skeleton contained in the dispersant can play a steric hindrance role, hindering the electrode slurry including the electrode material, the conductive agent and other component particles from approaching each other, thereby reducing the occurrence of agglomeration. At the same time, the polar organic matter can effectively bind to the surface of the component particles including the electrode material, the conductive agent and the like, so that the component particles including the electrode material, the conductive agent and the like are polar and produce a charge discharge effect between two adjacent particles, thereby reducing the agglomeration of each particle; and the polar organic matter can also react with the three-dimensional covalent organic skeleton or further include a softener, such as bonding between molecules, thereby playing a steric hindrance synergistic role, further hindering the particles in the electrode slurry from approaching each other to reduce the occurrence of agglomeration, thereby improving the dispersibility and stability of the electrode slurry, and at the same time, it can also reduce the viscosity of the electrode slurry and increase the solid content of the electrode slurry. In this way, the positive electrode active material or negative electrode active material or further components such as lithium supplement in the active material layer contained in the pole piece can be evenly distributed, the film quality of the active material layer can be improved, and a three-dimensional ion conductive network structure can be formed in the active material layer to improve the ion conductivity of the active material layer; when the dispersant in the above application embodiment contains a softener, it can also improve the mechanical properties such as elasticity and flexibility of the active material layer, thereby improving the structural stability of the active material layer. Therefore, the electrode material in the embodiment of the present application can improve the cycle performance and capacity density of the pole piece.

[0075] In the embodiment, in the electrode material of the embodiment of the present application, the amount of dispersant added is 0.01% to 1% of the mass of the electrode material, and can be 0.05% to 0.2%. In the exemplary embodiment, it can be 0.01%, 0.05%, 0.1%, 0.2%, 0.5%, 0.8%, 1% and other typical but non-limiting mass contents or the range between any two content values. The dispersant in this mass content range can improve the uniform dispersion of the electrode material in the prepared electrode slurry, thereby further improving the dispersibility and stability of the electrode slurry, and can also increase the solid content of the electrode slurry.

[0076] In the embodiment, when the electrode material of the embodiment of the present application contains a positive electrode active material, the electrode material is a positive electrode material. In this case, the positive electrode active material can be a lithium battery positive electrode active material or a sodium battery positive electrode active material. Then the corresponding electrode sheet is a positive electrode sheet, and the active material layer disposed on at least one surface of the positive electrode current collector is a positive electrode active material layer. In the exemplary embodiment, the positive electrode active material can be a conventional lithium battery positive electrode active material or a lithium battery positive electrode active material.

[0077] Similarly, when the electrode material of the embodiment of the present application contains a negative electrode active material, the electrode material is a negative electrode material. In this case, the negative electrode active material can be a lithium battery negative electrode active material or a sodium battery negative electrode active material. Then the corresponding electrode sheet is a negative electrode sheet, and the active material layer disposed on at least one surface of the negative electrode current collector is a negative electrode active material layer. In the exemplary embodiment, the negative electrode active material can be a conventional lithium battery negative electrode active material or a lithium battery negative electrode active material.

[0078] In addition, when the electrode material of the present embodiment contains a lithium supplement, the type of the lithium supplement can be a lithium supplement commonly used in the field of lithium batteries or sodium batteries. The content of the lithium supplement in the electrode material can also be the conventional amount of lithium supplement contained in lithium batteries or sodium batteries.

[0079] [Electrode sheet]

[0080] In a third aspect, the present application also provides an electrode sheet. The electrode sheet of the present application comprises a current collector and an active material layer disposed on at least one surface of the current collector, wherein the active material layer comprises the electrode material of the above-mentioned present application.

[0081] Since the electrode sheet of the embodiment of the present application contains the electrode material of the embodiment of the above text application, the electrode active material, conductive agent and other components in the active material layer of the electrode sheet of the embodiment of the present application are evenly dispersed, which improves the membrane surface density and capacity density. When the dispersant of the embodiment of the above text application contains a softener, due to the presence of the softener, it can also effectively improve the mechanical properties such as elasticity and toughness of the active material layer, effectively alleviate the undesirable phenomena such as pulverization of the active material layer during the charging and discharging process, and effectively improve the peel strength of the electrode sheet, and improve the cycle performance of the electrode sheet. In addition, the presence of components such as the three-dimensional covalent organic skeleton also forms a three-dimensional ion conductive network structure in the active material layer, which improves the ionic conductivity and other properties of the active material layer.

[0082] In addition, when the electrode material of the above text application embodiment contains positive electrode active material, the electrode sheet of the present application embodiment is a positive electrode sheet; when the electrode material of the above text application embodiment contains negative electrode active material, the electrode sheet of the present application embodiment is a negative electrode sheet.

[0083] In the embodiments, the active material layer of the electrode sheet of the embodiments of the present application generally includes components such as a binder and a conductive agent in addition to the electrode material of the embodiments of the present application.

[0084] When the active material layer of the electrode sheet of the embodiment of the present application includes components such as a binder and a conductive agent, the components such as the binder and the conductive agent may have conventional contents, and their materials may be corresponding material types commonly used in the electrode sheet field.

[0085] [Battery]

[0086] In a fourth aspect, the embodiments of the present application also provide a battery. The battery of the embodiments of the present application includes necessary components such as a positive electrode sheet, a negative electrode sheet, a diaphragm or a solid electrolyte, and of course other necessary or auxiliary components. Among them, the diaphragm or solid electrolyte is arranged between the positive electrode sheet and the negative electrode sheet. Among them, the positive electrode sheet is the electrode sheet of the above-mentioned embodiment of the present application, that is, the positive electrode active material layer contained in the positive electrode sheet includes the electrode material of the above-mentioned embodiment of the present application, and the electrode material of the above-mentioned embodiment of the present application includes the positive electrode active material.

[0087] Alternatively, the negative electrode sheet is the electrode sheet of the above-mentioned embodiment of the application, that is, the negative electrode active material layer contained in the negative electrode sheet includes the electrode material of the above-mentioned embodiment of the application, and the electrode material of the above-mentioned embodiment of the application includes the negative electrode active material.

[0088] Alternatively, the positive electrode sheet is the electrode sheet of the above-mentioned embodiment, and the electrode material contained in the electrode sheet of the above-mentioned embodiment includes positive electrode active material. Meanwhile, the negative electrode sheet is the electrode sheet of the above-mentioned embodiment, and the electrode material contained in the electrode sheet of the above-mentioned embodiment includes negative electrode active material.

[0089] Since at least one of the positive electrode sheet and the negative electrode sheet in the battery of the embodiment of the present application is the electrode sheet of the embodiment of the present application, the electrode sheet in the battery of the embodiment of the present application has high capacity density and structural stability, thereby giving the battery high energy density and cycle performance.

[0090] The following is a description of the composite lithium-rich material and its preparation method and application according to the embodiment of the present application through a number of specific embodiments.

[0091] 1. Dispersant Example:

[0092] Embodiment A1:

[0093] The present embodiments A1 to A8, comparative examples A1 to A3 and blank examples each provide a dispersant, and each dispersant contains a combination formula as shown in each embodiment in Table 1.

[0094] Each dispersant is prepared by mixing the components according to the combination formula shown in each embodiment in Table 1.

[0095] Table 1

[0096]

[0097]

[0098] 2. Lithium-ion battery example:

[0099] The present embodiments B1 to B8, comparative examples B1 to B3 and blank examples each provide a lithium ion battery. Each lithium ion battery is assembled into a lithium ion battery according to the following method:

[0100] 1) Positive electrode:

[0101] Under the same conditions, the positive electrode active material: Super P: PVDF: dispersant are mixed in a mass ratio of 9.65: 0.13: 0.22: 0.00965, and the positive electrode slurry is prepared in N-methylpyrrolidone solvent; the positive electrode slurry is subjected to coating-drying-cutting operations to prepare a positive electrode sheet, and the positive electrode sheet is baked in a vacuum oven at 100°C to remove trace water. Specifically, the positive electrode slurry in Example B1 contains the dispersant in Example A1, the positive electrode slurry in Example B2 contains the dispersant in Example A2, and so on, the positive electrode slurry in Comparative Example B3 contains the dispersant in Comparative Example A3.

[0102] 2) Negative electrode sheet: The negative electrode active material graphite, conductive agent Super P, thickener carboxymethyl cellulose (CMC), and binder styrene butadiene rubber (SBR) are mixed evenly in deionized water to form a negative electrode slurry, wherein the mass ratio of graphite: Super P: CMC: SBR is 95:2:0.5:2.5. The negative electrode slurry is coated on the current collector copper foil, and after drying-rolling-secondary drying process, the negative electrode sheet is made.

[0103] 3) Diaphragm: Use polyethylene (PE) diaphragm.

[0104] 4) Electrolyte: The electrolyte is a 1 mol / L LiPF6 solution, and the solvent is composed of EC (ethylene carbonate) and DEC (diethyl carbonate) in a volume ratio of 1:1.

[0105] 5) Assembly of secondary batteries:

[0106] The positive electrode sheet, negative electrode sheet, electrolyte and separator are assembled into a lithium-ion button battery according to the lithium-ion battery assembly requirements.

[0107] Related performance testing of lithium-ion batteries:

[0108] The lithium-ion batteries of the embodiments and comparative examples assembled in Section 5) were subjected to relevant performance tests as shown in Table 2 below, and the measured results are shown in Table 2 below.

[0109] Among them, the relevant performance test methods in Table 2 are as follows:

[0110] Viscosity test: The mixed positive electrode slurry is tested using a rotational viscometer, and the viscosity of the slurry at different times is recorded.

[0111] Electrode sheet resistivity test: The resistivity of the electrode in each embodiment and comparative example was calculated and tested by a four-probe method.

[0112] Flexibility test: bend the electrode 180° toward the current collector, observe the crease state of the electrode through an optical microscope, and repeat three times: intact is marked as +, with breakage but no detachment is marked as ○, and detachment or cracking is marked as ×.

[0113] Peel strength test: The obtained electrode was cut into 10cm×2cm strips, fixed on a 1mm thick steel plate with double-sided tape on the current collector side, and transparent tape was pasted on the coating layer. A 180° pulling peeling test was performed using a universal material testing machine at a peeling speed of 10cm / min.

[0114] Capacity retention rate test: Assemble the above positive electrode sheet, negative electrode sheet, electrolyte and separator into a lithium-ion button battery according to the lithium-ion battery assembly requirements, with a voltage range of 2.5-3.75V, 0.1C cycle for the first three cycles, and then 100 cycles at 1C.

[0115] Table 2

[0116]

[0117]

[0118] Combined with Table 1 above, it can be seen from the test results of Table 2: Comparative Examples B1 to B4 show that in Examples A1 to A4, one or more of each type of material in the three-dimensional covalent organic skeleton, polar organic matter, and softener are selected and compounded with the main material, SP, and PVDF to form a mixed slurry. When the content of each main component is within a reasonable range, the viscosity of the positive electrode slurry can be reduced, the fluidity of the positive electrode slurry can be improved, and the current viscosity level can be maintained to a large extent. It is not easy to gel, which greatly improves the processing performance of the material. The addition of the three-dimensional covalent organic skeleton can improve the ion conductivity of the material, so that the capacity retention rate of the battery is greatly improved. At the same time, the addition of the softener can improve the peeling force of the pole piece and increase the flexibility of the pole piece. At the same time, the corresponding lithium-ion battery performance is also improved relative to the lithium-ion battery in the comparative example.

[0119] By comparing Example B5 to Example B6, it can be seen that the addition ratio of polar molecules or three-dimensional covalent organic polymers in the dispersant in Examples A5 and A6 is reduced, the binding between the three-dimensional covalent organic polymer and the positive electrode material is reduced, the steric hindrance is also reduced, and the dispersibility of the particles is reduced, so that the initial viscosity and stable viscosity performance of the slurry are reduced. At the same time, the corresponding lithium-ion battery performance is also affected to a certain extent, such as the cycle performance in Example B5 is significantly improved.

[0120] By comparing Example B7 to Example B8, it can be seen that the role of the softener contained in the dispersant in Examples A7 and A8 is mainly to enhance the peeling force of the electrode and increase the flexibility of the electrode. Not adding the softener has little effect on the viscosity of the electrode, but adding too much will increase the initial viscosity of the slurry.

[0121] Comparing Examples B1 to B8 with Comparative Examples B1 to B3, it can be seen that the viscosity and stability of the positive electrode slurry in Examples B1 to B8 are significantly better than those in Comparative Examples B1 to B3, and the corresponding lithium-ion battery cycle performance is also significantly better than that in Comparative Examples B1 to B3.

[0122] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A dispersant comprising a three-dimensional covalent organic skeleton and a polar organic substance, wherein the polar organic substance contains a polar group, and the polar organic substance can be connected to the three-dimensional covalent organic skeleton through the polar group.

2. The dispersant according to claim 1, characterized in that: The three-dimensional covalent organic framework comprises at least one of the following (1) to (3): (1) The three-dimensional covalent organic framework comprises at least one of a small molecule three-dimensional organic framework and a polymer three-dimensional organic framework; (2) The specific surface area of ​​the three-dimensional covalent organic framework particles is 100 to 2000 m 2 / g; (3) The pore size of the particles of the three-dimensional covalent organic framework is 1 nm to 500 nm; (4) The porosity of the three-dimensional covalent organic framework particles is 20% to 80%.

3. The dispersant according to claim 2, characterized in that: The small molecule three-dimensional organic framework includes at least one of adamantane small molecules, cyclic hydrocarbon small molecules, tetrahedral structure small molecules, cubane small molecules, and prismane small molecules; The polymer three-dimensional organic skeleton includes at least one of adamantane polymers, cyclic hydrocarbon polymers, tetrahedral polymers, cubanes polymers, and prismane polymers.

4. The dispersant according to any one of claims 1 to 3, characterized in that: The polar groups contained in the polar organic matter include at least one of amino, hydroxyl, alkoxy, carboxyl, amide, sulfonic acid, phosphoric acid and nitro; and / or The polar organic matter includes small molecule polar compounds.

5. The dispersant according to claim 4, characterized in that: The polar organic matter containing the amino group includes at least one of aliphatic amine, isopropanolamine, o-aminophenol, m-aminophenol, and p-aminophenol; and / or The polar organic matter containing the hydroxyl group includes at least one of phenol, lactic acid, glucose, glycerol, and ethylene glycol; and / or The polar organic matter containing the carboxyl group includes at least one of a cinnamic acid derivative and a benzoic acid derivative.

6. The dispersant according to any one of claims 1 to 3 and 5, characterized in that: The mass ratio of the three-dimensional covalent organic framework to the polar organic matter is (5-30): (10-50); and / or It also includes at least one of a solvent and a softener; when the solvent is contained, the other components contained in the dispersant are dissolved in the solvent; when the softener is contained, the mass ratio of the softener to the three-dimensional covalent organic framework is (5-30): (10-50).

7. The dispersant according to claim 6, characterized in that: The dispersant contains the solvent, and the mass concentration of the three-dimensional covalent organic framework in the dispersant is 1% to 40%; and / or The solvent comprises at least one of N-methylpyrrolidone, dimethyl sulfoxide and dimethylformamide; and / or The softener includes a flexible resin softener.

8. An electrode material, characterized in that: The invention comprises a positive electrode active material or a negative electrode active material, or a mixture of the positive electrode active material or the negative electrode active material and a lithium supplement, and further comprises a dispersant, and the dispersant comprises the dispersant according to any one of claims 1 to 7.

9. An electrode sheet, characterized in that: It comprises a current collector and an active material layer arranged on at least one surface of the current collector, wherein the active material layer comprises the electrode material according to claim 8.

10. A battery comprising a positive electrode sheet and a negative electrode sheet, characterized in that: The positive electrode sheet is the electrode sheet according to claim 9, and the electrode material contained in the electrode sheet includes a positive electrode active material; and / or The negative electrode sheet is the electrode sheet according to claim 9, and the electrode material contained in the electrode sheet includes a negative electrode active material.

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