Lithium battery silicon-based negative electrode additive as well as preparation method and application thereof

Abstract

The invention relates to a silicon-based negative electrode additive for a lithium battery. The silicon-based negative electrode additive for the lithium battery comprises lithium-embedded polyamino-anthraquinone. The lithium battery silicon-based negative electrode additive provided by the embodiment of the invention comprises the lithium-intercalated polyamino-anthraquinone, and the lithium-intercalated polyamino-anthraquinone can provide additional active lithium ions for a battery system in charge and discharge cycles, so that lithium loss caused by generation of an SEI film on the surface of a negative electrode is made up, the first coulombic efficiency of the battery is improved, and the service life of the battery is prolonged. The release of the battery capacity is improved; meanwhile, the polyamino anthraquinone lithium has better mechanical property, solvent resistance, better elasticity and higher tensile strength, and can bear and buffer the volume change of silicon-based particles in the charge-discharge cycle process and improve the pulverization phenomenon of a silicon-based negative electrode, thereby enhancing the long cycle performance of the battery.

Description

Technical Field

[0001] The present application relates to lithium batteries, and in particular to silicon-based negative electrodes. Background Art

[0002] In recent years, with the booming development of the electric vehicle market, higher requirements have been placed on the endurance of electric vehicles. Among various new battery systems, solid-state lithium batteries use solid electrolytes instead of organic electrolytes, which is expected to break through the technical bottleneck of liquid lithium batteries and achieve higher energy density. The realization of high energy density of solid-state batteries depends on electrode materials with high specific capacity. Therefore, high-nickel ternary is generally used as the positive electrode in solid-state batteries, and a composite material of silicon compounds and graphite is used as the negative electrode. Although the specific capacity of silicon-based negative electrodes is much higher than that of graphite, it has two major problems: first, the volume expands greatly after lithium insertion, up to more than 300%, resulting in poor cyclability; second, the first coulomb efficiency after forming a full battery is low, which seriously affects the release of battery capacity. Summary of the invention

[0003] The embodiments of the present application provide a lithium battery silicon-based negative electrode additive and a preparation method and application thereof, so as to solve the technical problems of huge volume expansion and low initial coulombic efficiency of silicon-based negative electrodes after lithium insertion.

[0004] In a first aspect, an embodiment of the present application provides a lithium battery silicon-based negative electrode additive, wherein the lithium battery silicon-based negative electrode additive comprises: lithium-embedded polyaminoanthraquinone.

[0005] In a second aspect, an embodiment of the present application provides a method for preparing a silicon-based negative electrode additive for a lithium battery, the method for preparing a silicon-based negative electrode additive for a lithium battery comprising the following steps:

[0006] Providing polyaminoanthraquinone;

[0007] The lithium battery silicon-based negative electrode additive is obtained by using polyaminoanthraquinone as the positive electrode and lithium metal as the negative electrode to carry out lithium insertion reaction.

[0008] In some embodiments of the present application, the lithium insertion reaction is carried out in a three-electrode system or a button battery system.

[0009] In some embodiments of the present application, the current of the lithium insertion reaction is less than 0.1C.

[0010] In some embodiments of the present application, the endpoint of the lithium insertion reaction is that the voltage between the positive electrode and the negative electrode is 1.5V.

[0011] In some embodiments of the present application, providing polyaminoanthraquinone comprises the following steps:

[0012] dissolving diaminoanthraquinone in an organic solvent containing a protonic acid to obtain a premixed solution;

[0013] adding a strong oxidant to the premixed solution to cause diaminoanthraquinone to polymerize to generate polyaminoanthraquinone;

[0014] soaking the obtained polyaminoanthraquinone in an alkaline solution;

[0015] The alkaline solution is subjected to solid-liquid separation, and the separated polyaminoanthraquinone is washed and dried.

[0016] Wherein, the organic solvent is an aprotic polar organic solvent.

[0017] In some embodiments of the present application, the strong oxidant is at least one of permanganate, dichromate, and persulfate; and / or,

[0018] The organic solvent is at least one of N,N-dimethylformamide and dimethyl sulfoxide;

[0019] The base is aqueous ammonia.

[0020] In a third aspect, an embodiment of the present application provides a negative electrode material, wherein the negative electrode material comprises:

[0021] Silicon-based negative electrode materials for lithium batteries;

[0022] A lithium battery silicon-based negative electrode additive dispersed in the silicon-based negative electrode material,

[0023] Among them, the lithium battery silicon-based negative electrode additive is the lithium battery silicon-based negative electrode additive described in any embodiment of the first aspect, or the lithium battery silicon-based negative electrode additive prepared by the method described in any embodiment of the second aspect.

[0024] In some embodiments of the present application, the mass ratio of the silicon-based negative electrode material to the lithium battery silicon-based negative electrode additive is 5 to 20:1; and / or,

[0025] The negative electrode material also includes a binder and a conductive agent.

[0026] In a fourth aspect, an embodiment of the present application provides a lithium battery, wherein the lithium battery comprises the negative electrode material described in any embodiment of the third aspect.

[0027] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0028] The lithium battery silicon-based negative electrode additive provided in the embodiment of the present application includes lithium-embedded polyaminoanthraquinone. The lithium-embedded polyaminoanthraquinone can provide additional active lithium ions to the battery system during the charge and discharge cycle, compensate for the lithium loss caused by the formation of SEI film on the negative electrode surface, thereby improving the first coulombic efficiency of the battery and improving the release of the battery capacity; at the same time, the polyaminoanthraquinone lithium itself has good mechanical properties, solvent resistance, good elasticity and high tensile strength, can withstand and buffer the volume changes of silicon-based particles during the charge and discharge cycle, improve the pulverization phenomenon of the silicon-based negative electrode, and thus improve the long-cycle performance of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0030] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0031] Figure 1 A schematic flow chart of a method for preparing a silicon-based negative electrode additive for a lithium battery provided in an embodiment of the present application. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0033] Unless otherwise specified, the terms used herein should be understood as commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which this application belongs. In the event of a conflict, this specification takes precedence.

[0034] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0035] The existing silicon-based negative electrode has the technical problems of huge volume expansion after lithium insertion and low initial coulombic efficiency when forming a full battery.

[0036] The technical solution provided by the embodiments of the present application is to solve the above technical problems, and the overall idea is as follows:

[0037] In a first aspect, an embodiment of the present application provides a lithium battery silicon-based negative electrode additive, wherein the lithium battery silicon-based negative electrode additive comprises: lithium-embedded polyaminoanthraquinone.

[0038] It should be noted that the lithium battery silicon-based negative electrode additive described in the present application is mainly composed of lithium-intercalated polyaminoanthraquinone, but may also include some other substances. For example, the lithium-intercalated polyaminoanthraquinone may be prepared by electrochemically intercalating lithium into polyaminoanthraquinone, and electrolyte will be mixed into the polyaminoanthraquinone during the lithium intercalation process. In addition, the lithium battery silicon-based negative electrode additive described in the present application may also include silicon-based negative electrode additives known in the art.

[0039] The lithium battery silicon-based negative electrode additive provided in the embodiment of the present application includes lithium-embedded polyaminoanthraquinone. The lithium-embedded polyaminoanthraquinone can provide additional active lithium ions to the battery system during the charge and discharge cycle, compensate for the lithium loss caused by the formation of SEI film on the negative electrode surface, thereby improving the first coulombic efficiency of the battery and improving the release of the battery capacity; at the same time, the polyaminoanthraquinone lithium itself has good mechanical properties, solvent resistance, good elasticity and high tensile strength, can withstand and buffer the volume changes of silicon-based particles during the charge and discharge cycle, improve the pulverization phenomenon of the silicon-based negative electrode, and thus improve the long-cycle performance of the battery.

[0040] In a second aspect, an embodiment of the present application provides a method for preparing a silicon-based negative electrode additive for a lithium battery, the method for preparing a silicon-based negative electrode additive for a lithium battery comprising the following steps:

[0041] S1: providing polyaminoanthraquinone;

[0042] S2: Using polyaminoanthraquinone as the positive electrode and lithium metal as the negative electrode to carry out lithium insertion reaction to obtain the lithium battery silicon-based negative electrode additive.

[0043] It is easy to understand that lithium insertion reaction refers to the reaction of inserting lithium ions into the crystal structure of a material.

[0044] It is easy to understand that the polyaminoanthraquinone described in any embodiment of the first aspect of the present application can be prepared by the method described in the second aspect; the method described in any embodiment of the second aspect of the present application can prepare the polyaminoanthraquinone described in the first aspect. Since the method described in any embodiment of the second aspect of the present application can prepare the polyaminoanthraquinone described in the first aspect, any embodiment of the second aspect of the present application has the beneficial effects possessed by the first aspect of the present application, which will not be repeated here.

[0045] In some embodiments of the present application, the lithium insertion reaction is carried out in a three-electrode system or a button battery system.

[0046] It is easy to understand that implementing lithium insertion reaction through a three-electrode system or a button battery system has the advantages of easy assembly, stability and ease of use.

[0047] In some embodiments of the present application, the current of the lithium insertion reaction is less than 0.1C.

[0048] It is easy to understand that the C mentioned here is a well-known current unit in the field of lithium batteries. 1C refers to the current of the nominal capacity of the battery. When the battery is discharged to a voltage of 3.0V at a certain current, the time is exactly one hour. This certain current is 1C current.

[0049] In some embodiments of the present application, the endpoint of the lithium insertion reaction is that the voltage between the positive electrode and the negative electrode is 1.5V.

[0050] It is easy to understand that at a voltage of 1.5V, polyaminoanthraquinone is theoretically completely lithium-intercalated.

[0051] In some embodiments of the present application, providing polyaminoanthraquinone comprises the following steps:

[0052] S11: dissolving diaminoanthraquinone in an organic solvent containing a protonic acid to obtain a premixed solution;

[0053] S12: adding a strong oxidant to the premixed solution to polymerize the diaminoanthraquinone to generate polyaminoanthraquinone;

[0054] S13: soaking the obtained polyaminoanthraquinone in an alkaline solution;

[0055] S14: performing solid-liquid separation on the alkaline solution, washing and drying the separated polyaminoanthraquinone,

[0056] Wherein, the organic solvent is an aprotic polar organic solvent.

[0057] It is easy to understand that the protonic acid can be selected from common inorganic acids, such as sulfuric acid and hydrochloric acid. It is easy to understand that the protonic acid described in this application should not include acids that affect the reaction process, such as nitric acid.

[0058] The amount of the strong oxidant can be calculated based on the number of electrons lost to completely polymerize the diaminoanthraquinone. The strong oxidant can be used in excess.

[0059] In some embodiments of the present application, the strong oxidant is at least one of permanganate, dichromate, and persulfate; and / or,

[0060] The organic solvent is at least one of N,N-dimethylformamide and dimethyl sulfoxide;

[0061] The base is aqueous ammonia.

[0062] The beneficial effect of using ammonia water as the alkali is that ammonia water has a mild alkalinity and does not need to be strictly controlled in dosage, and ammonia has good water solubility and is easy to wash away.

[0063] In a third aspect, an embodiment of the present application provides a negative electrode material, wherein the negative electrode material comprises:

[0064] Silicon-based negative electrode materials for lithium batteries;

[0065] A lithium battery silicon-based negative electrode additive dispersed in the silicon-based negative electrode material,

[0066] Among them, the lithium battery silicon-based negative electrode additive is the lithium battery silicon-based negative electrode additive described in any embodiment of the first aspect, or the lithium battery silicon-based negative electrode additive prepared by the method described in any embodiment of the second aspect.

[0067] The negative electrode material is based on the lithium battery silicon-based negative electrode additive described in any embodiment of the first aspect, or the method described in any embodiment of the second aspect. The specific implementation of the negative electrode material can refer to the above embodiments and common knowledge in the field. Since the negative electrode material adopts part or all of the technical solutions of the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be repeated here.

[0068] In some embodiments of the present application, the mass ratio of the silicon-based negative electrode material to the lithium battery silicon-based negative electrode additive is 5 to 20:1; and / or,

[0069] The negative electrode material also includes a binder and a conductive agent.

[0070] The beneficial effect of the mass ratio of the silicon-based negative electrode material to the lithium battery silicon-based negative electrode additive being 5 to 20:1 is that it will not have a negative impact on the initial charging specific capacity of the negative electrode material, and can significantly improve the cycle life of the negative electrode material.

[0071] As an example, the mass ratio of the silicon-based negative electrode material to the lithium battery silicon-based negative electrode additive can be 5:1, 10:1, 15:1, or 20:1.

[0072] As an example, the binder may be sodium carboxymethyl cellulose or polyacrylic acid.

[0073] As an example, the conductive agent may be carbon black.

[0074] In a fourth aspect, an embodiment of the present application provides a lithium battery, wherein the lithium battery comprises the negative electrode material described in any embodiment of the third aspect.

[0075] The lithium battery is realized based on the negative electrode material described in any embodiment of the third aspect. The specific implementation of the lithium battery can refer to the above embodiments and common knowledge in the field. Since the lithium battery adopts part or all of the technical solutions of the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here.

[0076] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which specific conditions are not specified in the following examples are usually measured according to industry standards. If there is no corresponding industry standard, then the conditions recommended by the manufacturer are followed.

[0077] Example 1

[0078] This embodiment provides a lithium battery silicon-based negative electrode additive, which is prepared by the following steps:

[0079] Dissolve 1,4-diaminoanthraquinone in a DMF solution containing sulfuric acid, the concentration of which is 1 mol / L;

[0080] Then, potassium dichromate strong oxidant was added to the DMF solution, the molar ratio of diaminoanthraquinone to the strong oxidant was 1:2.5, and the DMF solution was stirred for 30 hours;

[0081] The generated polyaminoanthraquinone was soaked in 1 mol / L ammonia solution for 3 h;

[0082] collecting the polyaminoanthraquinone soaked in the ammonia solution by centrifugal separation, then washing the separated polyaminoanthraquinone with deionized water, and finally drying the washed polyaminoanthraquinone;

[0083] In a button battery, the obtained polyaminoanthraquinone is used as a positive electrode and lithium metal is used as a negative electrode for a discharge reaction. The discharge current is 0.1C, and polyaminoanthraquinone lithium is obtained after discharging to 1.5V.

[0084] This embodiment also provides a lithium ion battery, which is prepared by the following steps:

[0085] A graphite / silicon composite negative electrode material with a silicon-oxygen content of 35%, polyaminoanthraquinone lithium, a binder, and a conductive agent are mixed in a mass ratio of 85.5:9.5:3.5:1.5 to form a prefabricated negative electrode mixture, and deionized water is added to the prefabricated negative electrode mixture to prepare a negative electrode slurry, wherein the binder is polyacrylic acid and the conductive agent is Volcan-72 acetylene black;

[0086] Preparation of positive electrode slurry: lithium iron phosphate, a binder, and a conductive agent are mixed in a mass ratio of 95:3.5:1.5 to form a prefabricated positive electrode mixture, and ethylene carbonate is added to the prefabricated positive electrode mixture to prepare a positive electrode slurry, wherein the binder is polyvinylidene fluoride and the conductive agent is Volcan-72 acetylene black;

[0087] The positive electrode slurry and the negative electrode slurry are respectively coated on the current collector to obtain a positive electrode sheet and a negative electrode sheet;

[0088] The positive electrode sheet, negative electrode sheet, separator, electrolyte and battery shell are assembled into button batteries in a glove box. The separator is made of the base film product produced by China National Materials Lithium Membrane Co., Ltd., and the electrolyte is lithium bis(fluorosulfonyl)imide.

[0089] Example 2

[0090] This embodiment provides a lithium battery silicon-based negative electrode additive, which is prepared by the following method:

[0091] Dissolve 1,5-diaminoanthraquinone in a DMF solution containing sulfuric acid, the concentration of which is 1 mol / L;

[0092] Then, potassium permanganate strong oxidant was added to the DMF solution, the molar ratio of diaminoanthraquinone to the strong oxidant was 1:4, and the DMF solution was stirred for 36 hours;

[0093] The generated polyaminoanthraquinone was soaked in 1 mol / L ammonia solution for 5 h;

[0094] collecting the polyaminoanthraquinone soaked in the ammonia solution by centrifugal separation, then washing the separated polyaminoanthraquinone with deionized water, and finally drying the washed polyaminoanthraquinone;

[0095] In a button battery, the obtained polyaminoanthraquinone is used as a positive electrode and lithium metal is used as a negative electrode for a discharge reaction. The discharge current is 0.1C, and polyaminoanthraquinone lithium is obtained after discharging to 1.5V.

[0096] This embodiment also provides a lithium ion battery, which is prepared by the following steps:

[0097] A graphite / silicon composite negative electrode material with a silicon-oxygen content of 35%, polyaminoanthraquinone lithium, a binder, and a conductive agent are mixed in a mass ratio of 85.5:9.5:3.5:1.5 to form a prefabricated negative electrode mixture, and deionized water is added to the prefabricated negative electrode mixture to prepare a negative electrode slurry, wherein the binder is polyacrylic acid and the conductive agent is Volcan-72 acetylene black;

[0098] Preparation of positive electrode slurry: lithium iron phosphate, a binder, and a conductive agent are mixed in a mass ratio of 95:3.5:1.5 to form a prefabricated positive electrode mixture, and ethylene carbonate is added to the prefabricated positive electrode mixture to prepare a positive electrode slurry, wherein the binder is polyvinylidene fluoride and the conductive agent is Volcan-72 acetylene black;

[0099] The positive electrode slurry and the negative electrode slurry are respectively coated on the current collector to obtain a positive electrode sheet and a negative electrode sheet;

[0100] The positive electrode sheet, negative electrode sheet, separator, electrolyte and battery shell are assembled into button batteries in a glove box. The separator is made of the base film product produced by China National Materials Lithium Membrane Co., Ltd., and the electrolyte is lithium bis(fluorosulfonyl)imide.

[0101] Example 3

[0102] This embodiment provides a lithium battery silicon-based negative electrode additive, which is prepared by the following method:

[0103] Dissolve 2,6-diaminoanthraquinone in a DMF solution containing sulfuric acid, the concentration of which is 1 mol / L;

[0104] Then, potassium dichromate strong oxidant was added to the DMF solution, the molar ratio of diaminoanthraquinone to the strong oxidant was 1:2.5, and the DMF solution was stirred for 30 hours;

[0105] The generated polyaminoanthraquinone was soaked in 1 mol / L ammonia solution for 3 h;

[0106] collecting the polyaminoanthraquinone soaked in the ammonia solution by centrifugal separation, then washing the separated polyaminoanthraquinone with deionized water, and finally drying the washed polyaminoanthraquinone;

[0107] In a button battery, the obtained polyaminoanthraquinone is used as a positive electrode and lithium metal is used as a negative electrode for a discharge reaction. The discharge current is 0.1C, and polyaminoanthraquinone lithium is obtained after discharging to 1.5V.

[0108] This embodiment also provides a lithium ion battery, which is prepared by the following steps:

[0109] A graphite / silicon composite negative electrode material with a silicon-oxygen content of 35%, polyaminoanthraquinone lithium, a binder, and a conductive agent are mixed in a mass ratio of 81:14:3.5:1.5 to form a prefabricated negative electrode mixture, and deionized water is added to the prefabricated negative electrode mixture to prepare a negative electrode slurry, wherein the binder is polyacrylic acid and the conductive agent is Volcan-72 acetylene black;

[0110] Preparation of positive electrode slurry: lithium iron phosphate, a binder, and a conductive agent are mixed in a mass ratio of 95:3.5:1.5 to form a prefabricated positive electrode mixture, and ethylene carbonate is added to the prefabricated positive electrode mixture to prepare a positive electrode slurry, wherein the binder is polyvinylidene fluoride and the conductive agent is Volcan-72 acetylene black;

[0111] The positive electrode slurry and the negative electrode slurry are respectively coated on the current collector to obtain a positive electrode sheet and a negative electrode sheet;

[0112] The positive electrode sheet, negative electrode sheet, separator, electrolyte and battery shell are assembled into button batteries in a glove box. The separator is made of the base film product produced by China National Materials Lithium Membrane Co., Ltd., and the electrolyte is lithium bis(fluorosulfonyl)imide.

[0113] Comparative Example

[0114] This comparative example provides a lithium-ion battery, and the preparation steps thereof are different from those of Example 1, except that the negative electrode slurry does not contain polyaminoanthraquinone lithium.

[0115] The details are as follows:

[0116] This comparative example also provides a lithium ion battery, which is prepared by the following steps:

[0117] A graphite / silicon composite negative electrode material with a silicon-oxygen content of 35%, a binder, and a conductive agent are mixed in a mass ratio of 95:3.5:1.5 to form a prefabricated negative electrode mixture, and deionized water is added to the prefabricated negative electrode mixture to prepare a negative electrode slurry, wherein the binder is polyacrylic acid and the conductive agent is Volcan-72 acetylene black;

[0118] Preparation of positive electrode slurry: lithium iron phosphate, a binder, and a conductive agent are mixed in a mass ratio of 95:3.5:1.5 to form a prefabricated positive electrode mixture, and ethylene carbonate is added to the prefabricated positive electrode mixture to prepare a positive electrode slurry, wherein the binder is polyvinylidene fluoride and the conductive agent is Volcan-72 acetylene black;

[0119] The positive electrode slurry and the negative electrode slurry are respectively coated on the current collector to obtain a positive electrode sheet and a negative electrode sheet;

[0120] The positive electrode sheet, negative electrode sheet, separator, electrolyte and battery shell are assembled into button batteries in a glove box. The separator is made of the base film product produced by China National Materials Lithium Membrane Co., Ltd., and the electrolyte is lithium bis(fluorosulfonyl)imide.

[0121] Related experiments and effect data:

[0122] The lithium ion batteries of Examples 1 to 3 and the comparative example were subjected to constant current charge and discharge tests under the conditions of a charge current density of 0.5C and a discharge current density of 1C. The test results are shown in Table 1.

[0123] Table 1 Constant current charge and discharge test data of lithium ions in Examples 1 to 3 and Comparative Example

[0124]

[0125] Compared with the comparative example, Examples 1 to 3 are equivalent to that a part of the graphite / silicon negative electrode material in the negative electrode of the lithium battery is replaced by an equal mass of polyaminoanthraquinone lithium. As can be seen from Table 1, the first charge specific capacity of Examples 1 to 3 and the comparative example is basically at the same level. This shows that in Examples 1 to 3, within the range of 5 to 20:1 of the mass ratio of the silicon-based negative electrode material to the silicon-based negative electrode additive of the lithium battery, the use of an equal mass of polyaminoanthraquinone lithium to replace the graphite / silicon negative electrode material has no negative impact on the first charge specific capacity of the lithium battery. Compared with the comparative example, the lithium batteries of Examples 1 to 3 have significantly improved first coulombic efficiency and cycle life, which shows that adding polyaminoanthraquinone lithium to the negative electrode of the lithium battery in Examples 1 to 3 can effectively increase its cycle life and slow down the performance loss of the negative electrode material.

[0126] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0127] In the present application, in the absence of any contrary description, the directional words used, such as "upper" and "lower", are specifically the directions of the drawings in the accompanying drawings. In addition, in the description of the present application specification, the terms "including", "comprising", etc. refer to "including but not limited to". Moreover, the terms "including", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of further restrictions, the elements defined by the sentence "including..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements. In this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B, which can represent: A exists alone, A and B exist at the same time, and B exists alone. For the association relationship of more than three associated objects described by "and / or", it means that any one of these three associated objects can exist alone, or any at least two of them exist at the same time. For example, for A, and / or B, and / or C, it can be represented that any one of A, B, and C exists alone, or any two of them exist at the same time, or three of them exist at the same time. In this article, "at least one" refers to one or more, and "multiple" refers to two or more. "At least one", "the following at least one (individual)" or similar expressions refer to any combination of these items, including any combination of single (individual) or plural (individual). For example, "at least one (individual) of a, b, or c", or "at least one (individual) of a, b, and c", can all represent: a, b, c, ab (i.e. a and b), ac, bc, or abc, wherein a, b, and c can be single or multiple, respectively.

[0128] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A lithium battery silicon-based negative electrode additive, characterized in that: The lithium battery silicon-based negative electrode additive includes: lithium-embedded polyaminoanthraquinone.

2. A method for preparing a lithium battery silicon-based negative electrode additive, characterized in that: The preparation method of the lithium battery silicon-based negative electrode additive comprises the following steps: Providing polyaminoanthraquinone; The lithium battery silicon-based negative electrode additive is obtained by using polyaminoanthraquinone as the positive electrode and lithium metal as the negative electrode to carry out lithium insertion reaction.

3. The method for preparing a silicon-based negative electrode additive for a lithium battery according to claim 2, characterized in that: The lithium insertion reaction is carried out in a three-electrode system or a button cell system.

4. The method for preparing a silicon-based negative electrode additive for a lithium battery according to claim 3, characterized in that: The current of the lithium insertion reaction is less than 0.1C.

5. The method for preparing a silicon-based negative electrode additive for lithium batteries according to claim 3, characterized in that: The end point of the lithium insertion reaction is that the voltage between the positive electrode and the negative electrode is 1.5V.

6. The method for preparing a silicon-based negative electrode additive for lithium batteries according to claim 2, characterized in that: The method of providing polyaminoanthraquinone comprises the following steps: dissolving diaminoanthraquinone in an organic solvent containing a protonic acid to obtain a premixed solution; adding a strong oxidant to the premixed solution to cause diaminoanthraquinone to polymerize to generate polyaminoanthraquinone; soaking the obtained polyaminoanthraquinone in an alkaline solution; The alkaline solution is subjected to solid-liquid separation, and the separated polyaminoanthraquinone is washed and dried. Wherein, the organic solvent is an aprotic polar organic solvent.

7. The method for preparing a silicon-based negative electrode additive for a lithium battery according to claim 6, characterized in that: The strong oxidant is at least one of permanganate, dichromate and persulfate; and / or, The organic solvent is at least one of N,N-dimethylformamide and dimethyl sulfoxide; The base is aqueous ammonia.

8. A negative electrode material, characterized in that The negative electrode material comprises: Silicon-based negative electrode materials for lithium batteries; A lithium battery silicon-based negative electrode additive dispersed in the silicon-based negative electrode material, Wherein, the silicon-based negative electrode additive for lithium batteries is the silicon-based negative electrode additive for lithium batteries according to claim 1, or the silicon-based negative electrode additive for lithium batteries prepared by the method described in any one of claims 2 to 7.

9. The negative electrode material according to claim 8, characterized in that The mass ratio of the silicon-based negative electrode material to the lithium battery silicon-based negative electrode additive is 5 to 20:1; and / or, The negative electrode material also includes a binder and a conductive agent.

10. A lithium battery, characterized in that: The lithium battery comprises the negative electrode material according to claim 8 or 9.

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