CN116598505A - Negative electrode slurry and preparation method thereof, sodium ion battery - Google Patents

Abstract

The invention discloses a negative electrode slurry, a preparation method thereof, and a sodium ion battery. The negative electrode slurry includes a thickener and a negative electrode material, and the thickener includes a high molecular weight polymer of structural units shown in formula (I): Wherein, R ₁ is a branched chain structure with 1-10 C atoms at the end of -COOH, R ₂ is a branched chain structure with 1-10 C atoms at the end of an acidic group, and R ₃ is 1-10 C atoms The terminal is a branched chain structure of ‑COOR ₄ ester group, R ₄ is a saturated alkane with 1‑5 carbon atoms, and, 70%≤x≤95%, 0%≤y≤10%, 5%≤z ≤30%, the viscosity stability of the negative electrode slurry is high, and the preparation cost is low.

Description

Negative electrode slurry and preparation method thereof, sodium ion battery

technical field

The invention relates to the technical field of sodium ion batteries, in particular to a negative electrode slurry, a preparation method thereof, and a sodium ion battery.

Background technique

The rapid development of new energy vehicles has increased the huge demand for secondary batteries. However, the global lithium resources are poor and unevenly distributed, resulting in a shortage of upstream lithium mines, and the price of lithium salt raw materials is rising year by year. However, sodium-ion batteries not only have low cost of raw materials and abundant sources, they are superior to lithium-ion batteries in terms of fast charging performance, high and low temperature performance, and safety, and the production of sodium-ion batteries can continue to use the production line equipment of lithium-ion batteries. Low. Therefore, research on Na-ion batteries has gradually increased.

Due to the small spacing between graphite layers, sodium ions with larger radii need more energy to intercalate between graphite layers, and cannot perform reversible deintercalation within the effective potential window. Relevant personnel believe that traditional graphite cannot be used as the negative electrode of sodium-ion batteries, so , the current negative electrode materials in sodium-ion batteries are mainly hard carbon. However, hard carbon materials with higher energy density have high alkalinity (PH=10.0-11.0) due to their special microstructure. In the homogenization process of the negative electrode of the sodium ion battery, the high alkalinity of the hard carbon can easily cause the macromolecular chain scission of the commonly used thickener sodium carboxymethylcellulose (CMC), resulting in unstable viscosity of the negative electrode slurry system. At the same time, it is easy to use The demulsification of the binder (SBR) causes the negative electrode slurry to settle, which can easily cause the slurry to be over-flowed and scrapped, reducing the overall yield of the production line.

Contents of the invention

One of the objectives of the present invention is to provide a negative electrode slurry, a preparation method thereof, and a sodium ion battery, which can improve the viscosity stability of the negative electrode slurry and avoid sedimentation.

In order to achieve the above object, the present invention provides a negative electrode slurry, including a thickener, and the thickener includes a high molecular weight polymer of structural units shown in formula (I):

Among them, R ₁ is a branched chain structure with 1-10 C atoms ending in -COOH, R ₂ is a branched chain structure with 1-10 C atoms ending in an acidic group, and R ₃ is 1-10 C atoms The terminal is a branched chain structure of -COOR ₄ ester group, R ₄ is a saturated alkane with 1-5 carbon atoms, and, 70%≤x≤95%, 0%≤y≤10%, 5%≤z ≤30%.

Wherein, the acidic group includes -SO ₃ H.

Wherein, the negative electrode slurry also includes a negative electrode material and a binder;

In parts by weight, the thickener is 0.3-2.0 parts by weight, the negative electrode material is 20-50 parts by weight, and the binder is 0.5-3.5 parts by weight.

Wherein, the negative electrode slurry further includes deionized water and a conductive agent, the deionized water is 40-60 parts by weight, and the conductive agent is 0.5-3.0 parts by weight.

Wherein, the negative electrode material includes hard carbon;

And/or, the binder includes any one or more of polyvinylidene fluoride, acrylonitrile multi-polymer, perfluorosulfonic acid resin, sodium carboxymethyl cellulose, styrene-butadiene rubber, polymethyl acrylate;

And/or, the conductive agent includes any one or more of conductive carbon black, single-walled carbon nanotubes, multi-walled carbon nanotubes, graphene, conductive graphite and carbon fibers.

In order to achieve the above object, the present invention also provides a method for preparing negative electrode slurry, comprising:

Thickener, conductive agent and negative electrode material are mixed, obtain pre-mixture; Wherein, described thickener comprises the macromolecule polymer of structural unit shown in formula (I):

Among them, R ₁ is a branched chain structure with 1-10 C atoms ending in -COOH, R ₂ is a branched chain structure with 1-10 C atoms ending in an acidic group, and R ₃ is 1-10 C atoms The terminal is a branched chain structure of -COOR ₄ ester group, R ₄ is a saturated alkane with 1-5 carbon atoms, and, 70%≤x≤95%, 0%≤y≤10%, 5%≤z ≤30%

mixing the premix and deionized water, and kneading the thickener and the negative electrode material to obtain an intermediate mixture;

Mixing the intermediate mixture, the thickener and the deionized water to obtain a quasi-slurry;

The quasi-slurry and the binder are mixed to obtain the negative electrode slurry.

Wherein, 0.3-2.0 parts by weight of the thickener, 20-50 parts by weight of the negative electrode material, and 0.5-3.5 parts by weight of the binder are mixed to obtain a premix;

And/or, adding 23-35 parts by weight of the deionized water to the premix and mixing to obtain the intermediate mixture;

And/or, adding 0.1-1.0 parts by weight of the thickener and 17-25 parts by weight of the deionized water to the intermediate mixture for mixing to obtain the quasi-slurry;

And/or, add 0.5-3.5 parts of binder to the quasi-slurry and mix to obtain the negative electrode slurry.

Wherein, the thickener, the conductive agent and the negative electrode material are mixed for 5-10 minutes at a speed of 10-25 rpm in revolution and 500-1000 rpm in rotation to obtain the pre-mixture;

And/or, the pre-mixture and the deionized water undergo a kneading reaction for 30-90 minutes at a speed of 5-20 rpm in revolution and 0 rpm in rotation to obtain the intermediate mixture;

And/or, the intermediate mixture, the thickener and the deionized water are mixed for 30-90min at a speed of 15-30rpm in revolution and 1200-2000rpm in rotation to obtain the quasi-slurry;

And/or, the quasi-slurry and the binder are mixed for 15-60 minutes at a speed of 15-30 rpm in revolution and 500-1500 rpm in rotation to obtain the negative electrode slurry.

Wherein, the thickener is obtained through the following steps:

Mix deionized water, surfactants and monomer materials to obtain a pre-emulsion;

removing oxygen from the pre-emulsion;

dripping the initiator into the pre-emulsion after oxygen removal to carry out polymerization reaction, and precipitate the thickener micelle;

The thickener micelle is processed to obtain the thickener.

Wherein, the surfactant includes one or more of sodium dodecylbenzenesulfonate, allyl ether sulfonate, polyether ammonium phosphate containing double bonds;

The monomer material includes one or more of acrylate, acrylic acid, and propylene sulfonic acid;

The initiator includes one or more of ammonium sulfate, sodium persulfate, dialkyl peroxide and ester peroxide.

Wherein, the mass ratio of the surfactant to the monomer material is 1:0.001-0.15;

The mass ratio of the surfactant to the initiator is 1:0.005-0.015;

The deionized water, the surfactant and the monomer material are mixed at room temperature;

removing oxygen from the pre-emulsion in an inert gas atmosphere at a temperature of 60-90°C;

The pre-emulsion polymerization is carried out for 1-4 hours, and the thickener micelle is precipitated.

In order to achieve the above object, the present invention also provides a sodium ion battery, comprising a positive electrode sheet, a separator and a negative electrode sheet, wherein the positive electrode sheet, the separator and the negative electrode sheet are sequentially stacked or sequentially nested;

The negative electrode sheet is made of the negative electrode slurry provided in the first aspect of the present application.

The negative electrode slurry provided by the present invention includes a thickener and a negative electrode material. In the high molecular polymer of the thickener, _R1 is a branched chain structure with 1-10 C atoms at the end of -COOH, and _R2 is 1- The end of 10 C atoms is a branched chain structure of an acidic group, _R3 is a branched structure of 1-10 C atoms end of which is a -COOR ₄ ester group, _R4 is a saturated carbon atom of 1-5 Alkanes, and, 70%≤x≤95%, 0%≤y≤10%, 5%≤z≤30%, that is, the main chain structure of the thickener is a stable organic hydrocarbon chain, which will not encounter high alkali A chain scission reaction occurs, thereby ensuring the stability of the entire macromolecular chain, thereby ensuring the stability of the dispersion system of the negative electrode slurry. The thickener currently used in the negative electrode slurry of sodium ion batteries is carboxymethyl cellulose (CMC), which belongs to anionic water-soluble cellulose ethers, and its main chain structure contains ether bonds -CHR ₄ -O-CHR ₅ -, the ether bond is prone to chain scission reaction under the action of high alkali, resulting in the breakage of polymer macromolecular chains, resulting in a decrease in the viscosity of the negative electrode slurry, and the stable state of the solid-liquid mixed system is easily destroyed.

In addition, the pH value of the 1 wt% aqueous solution of the thickener in the negative electrode slurry provided by the invention is 1.0 to 3.0, while the pH value of the 1 wt% aqueous solution containing -COOH acidic groups in carboxymethylcellulose (CMC) is 6.5 to 6.5. 8.0, therefore, the ester group in the thickener provided by the present invention can enhance the compatibility with the hard carbon negative electrode, without additional use of acidic neutralizer, neutralization reaction can occur with the basic negative electrode material, so that the negative electrode can be prepared The alkalinity of the quasi-slurry in the slurry process is at a normal level (PH=7.5-9.0), which avoids the demulsification and agglomeration of the binder due to high alkalinity, thereby avoiding the abnormality of the processing process caused by the negative electrode slurry settling.

Since no additional acid neutralizer is used, the production process of the negative electrode slurry can be simplified, and the acid neutralizer is omitted, which reduces the production cost of the negative electrode slurry, and at the same time increases the proportion of the negative electrode material, thereby improving the efficiency of the sodium-ion battery. Energy Density. Moreover, the thickener with a certain acidity can neutralize the alkalinity of the quasi-slurry to a normal level, therefore, the selection range of the binder can be increased, the manufacturing cost of the sodium-ion battery can be further reduced, and it is beneficial to promote the development of the sodium-ion battery. industrial application.

Description of drawings

The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the description, together with the following specific embodiments, are used to explain the present invention, but do not constitute a limitation to the present invention.

Fig. 1 is the flow chart of the preparation method of a kind of negative electrode slurry provided by the embodiment of the present invention;

FIG. 2 shows the test results of the viscosity stability of negative electrode slurries prepared according to Examples 1 to 4, Comparative Example 1 and Comparative Example 2. FIG.

Detailed ways

Specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described here are only used to illustrate and explain the present invention, and are not intended to limit the present invention. It will be apparent to one skilled in the art that the present invention may be practiced without some of these specific details. The following description of the embodiments is only to provide a better understanding of the present invention by showing examples of the present invention.

It should be noted that, in this document, the terms "comprising", "comprising" or any other variation thereof are intended to cover a non-exclusive inclusion such that a process, method, article or apparatus comprising a set of elements includes not only those elements, It also includes other elements not expressly listed, or elements inherent in the process, method, article, or apparatus. Without further limitations, an element defined by the statement "comprising..." does not exclude the presence of additional identical elements in the process, method, article or device that includes the element.

In the first aspect, the embodiment of the present invention provides a negative electrode slurry, which can be applied to prepare a negative electrode sheet of a sodium ion battery.

Negative electrode slurry comprises binding agent, thickener and negative electrode material, and thickener comprises the macromolecule polymer of structural unit shown in formula (I):

Among them, R ₁ is a branched chain structure with 1-10 C atoms ending in -COOH, R ₂ is a branched chain structure with 1-10 C atoms ending in an acidic group, and R ₃ is 1-10 C atoms The terminal is a branched chain structure of -COOR ₄ ester group, R ₄ is a saturated alkane with 1-5 carbon atoms, and, 70%≤x≤95%, 0%≤y≤10%, 5%≤z ≤30%.

The thickener currently used in the negative electrode slurry of sodium ion batteries is carboxymethyl cellulose (CMC), which is an anionic water-soluble cellulose ether, and its main chain structure contains ether bonds -CHR ₄ -O-CHR ₅ - , the ether bond is prone to chain scission reaction under the action of high alkali, resulting in the breakage of the polymer macromolecular chain, resulting in a decrease in the viscosity of the negative electrode slurry, and the stable state of the solid-liquid mixed system is easily destroyed. However, the main chain structure of the thickener provided in the examples of the present application is a stable organic hydrocarbon chain, which will not cause chain scission reaction when encountering high alkali, and can ensure the stability of the entire macromolecular chain, thereby ensuring the dispersion system of the negative electrode slurry of stability.

In addition, the pH value of the 1 wt% aqueous solution of the thickener in the negative electrode slurry provided by the invention is 1.0 to 3.0, while the commonly used thickener, due to the -COOH acidic group in carboxymethyl cellulose (CMC) The PH value of 1wt% aqueous solution is 6.5～8.0, therefore, the ester group in the thickener provided by the present invention can enhance the compatibility with negative electrode materials (such as hard carbon), without additional use of acidic neutralizer, can be used with alkali The neutralization reaction of the negative electrode material will make the alkalinity of the quasi-slurry in the process of preparing the negative electrode slurry at a normal level (PH=7.5～9.0), and avoid the demulsification and agglomeration of the binder due to high alkalinity, thereby avoiding The sedimentation of the negative electrode slurry leads to abnormalities in the processing process.

Since no additional acid neutralizer is used, the production process of the negative electrode slurry can be simplified, and the acid neutralizer is omitted, which reduces the production cost of the negative electrode slurry, and at the same time increases the proportion of the negative electrode material, thereby improving the efficiency of the sodium-ion battery. Energy Density. Moreover, the thickener with a certain acidity can neutralize the alkalinity of the quasi-slurry to a normal level, therefore, the selection range of the binder can be increased, the manufacturing cost of the sodium-ion battery can be further reduced, and it is beneficial to promote the development of the sodium-ion battery. industrial application.

In some embodiments, the acidic group in R ₂ includes -SO ₃ H, and other acidic groups can also be used.

In some embodiments, the negative electrode material includes hard carbon.

In some embodiments, the negative electrode slurry also includes a binder, that is, the negative electrode slurry includes a thickener, a negative electrode material and a binder, wherein the thickener is 0.3-2.0 parts by weight, the negative electrode material is 20-50 parts by weight, 0.5-3.5 parts by weight of binder.

In some embodiments, the binder includes any one or more of polyvinylidene fluoride, acrylonitrile multi-polymer, perfluorosulfonic acid resin, sodium carboxymethyl cellulose, styrene-butadiene rubber, and polymethyl acrylate.

In this embodiment, the thickener can be used to change the dispersion stability of the negative electrode slurry components, and the binder can be used to change the interaction between the negative electrode slurry components and the substrate, thereby improving the negative electrode in the subsequent process. Stability and uniformity of slurry coating and pole pieces. Because the thickener provided by the present invention has a certain acidity, it can neutralize with alkaline negative electrode materials, so that the alkalinity of the quasi-slurry in the process of preparing the negative electrode slurry is at a normal level (PH=7.5～9.0), Avoid demulsification and agglomeration of the binder due to high alkalinity, thereby avoiding abnormalities in the processing process caused by the negative electrode slurry settling.

In some embodiments, the negative electrode slurry further includes deionized water and a conductive agent, wherein the deionized water is 40-60 parts by weight, and the conductive agent is 0.5-3.0 parts by weight.

In some embodiments, the conductive agent includes any one or more of conductive carbon black, single-walled carbon nanotubes, multi-walled carbon nanotubes, graphene, conductive graphite, and carbon fibers.

The negative electrode slurry provided by the present invention includes a thickener and a negative electrode material. In the high molecular polymer of the thickener, _R1 is a branched chain structure with 1-10 C atoms at the end of -COOH, and _R2 is 1- The end of 10 C atoms is a branched chain structure of an acidic group, _R3 is a branched structure of 1-10 C atoms end of which is a -COOR ₄ ester group, _R4 is a saturated carbon atom of 1-5 Alkanes, and, 70%≤x≤95%, 0%≤y≤10%, 5%≤z≤30%, that is, the main chain structure of the thickener is a stable organic hydrocarbon chain, which will not encounter high alkali A chain scission reaction occurs, thereby ensuring the stability of the entire macromolecular chain, thereby ensuring the stability of the dispersion system of the negative electrode slurry.

In addition, the thickener 1wt% aqueous solution pH value in the negative electrode slurry provided by the present invention is 1.0～3.0, and the 1wt% aqueous solution pH value containing-COOH acidic group in carboxymethylcellulose is 6.5～8.0, therefore , the ester group in the thickener provided by the present invention can enhance the compatibility with the hard carbon negative electrode, without additional use of an acidic neutralizer, it can neutralize the alkaline negative electrode material, making the process of preparing negative electrode slurry The alkalinity of the quasi-slurry in the medium is at a normal level (PH=7.5-9.0), which avoids the demulsification and agglomeration of the binder due to high alkalinity, thereby avoiding the abnormality of the processing process caused by the negative electrode slurry settling.

In addition, since no additional acid neutralizer is used, the production process of the negative electrode slurry can be simplified, and the acid neutralizer is omitted, which reduces the production cost of the negative electrode slurry, and at the same time increases the proportion of negative electrode materials, thereby increasing the concentration of sodium ions. The energy density of the battery. Moreover, the thickener with a certain acidity can neutralize the alkalinity of the quasi-slurry to a normal level, therefore, the selection range of the binder can be increased, the manufacturing cost of the sodium-ion battery can be further reduced, and it is beneficial to promote the development of the sodium-ion battery. industrial application.

In a second aspect, embodiments of the present invention provide a method for preparing negative electrode slurry. FIG. 1 is a flowchart of a method for preparing negative electrode slurry provided by an embodiment of the present invention.

Referring to Fig. 1, the preparation method of negative electrode slurry comprises:

S10, mixing the thickener, the conductive agent and the negative electrode material to obtain a premixture; wherein the thickener includes a high molecular weight polymer of structural units shown in formula (I):

Among them, R ₁ is a branched chain structure with 1-10 C atoms ending in -COOH, R ₂ is a branched chain structure with 1-10 C atoms ending in an acidic group, and R ₃ is 1-10 C atoms The terminal is a branched chain structure of -COOR ₄ ester group, R ₄ is a saturated alkane with 1-5 carbon atoms, and, 70%≤x≤95%, 0%≤y≤10%, 5%≤z ≤30%.

In some embodiments, 0.3-2.0 parts by weight of the thickener, 20-50 parts by weight of the negative electrode material, and 0.5-3.5 parts by weight of the binder are mixed to obtain a premixture.

In some embodiments, the thickener, the conductive agent and the negative electrode material are mixed for 5-10 minutes at a speed of 10-25 rpm in revolution and 500-1000 rpm in rotation to obtain a premixture.

In some embodiments, the thickener in the embodiments of the present invention is obtained through the following steps:

S11, mixing deionized water, a surfactant and a monomer material to obtain a pre-emulsion.

Wherein, the surfactant includes one or more of sodium dodecylbenzenesulfonate, allyl ether sulfonate, polyether ammonium phosphate containing double bonds;

The monomer material includes one or more of acrylate, acrylic acid, and acrylic sulfonic acid.

In some embodiments, the deionized water, the surfactant and the monomer material are mixed at room temperature, and the mass ratio of the surfactant to the monomer material is 1:0.001-0.15.

S12, removing oxygen in the pre-emulsion.

In some embodiments, oxygen is removed from the pre-emulsion in an atmosphere of an inert gas (such as nitrogen) at a temperature of 60-90°C.

S13, dropping the initiator into the deoxidized pre-emulsion, so that the surfactant and the monomer material undergo a polymerization reaction, and the thickener micelle is precipitated.

Wherein, the initiator includes one or more of ammonium sulfate, sodium persulfate, dialkyl peroxide and ester peroxide.

In some embodiments, the mass ratio of the surfactant to the initiator is 1:0.005-0.015, the pre-emulsion polymerization is carried out for 1-4 hours, and thickener micelle is precipitated.

S14, processing the thickener micelle to obtain a thickener.

In some embodiments, the thickener colloids are filtered, dried and pulverized to obtain the finished thickener. The embodiments of the present invention do not limit the specific methods of pressure filtration, drying and pulverization.

S20, mixing the premix and deionized water, and kneading the thickener and the negative electrode material to obtain an intermediate mixture.

In some embodiments, 23-35 parts by weight of deionized water is added to the premix and mixed to obtain an intermediate mixture.

In some embodiments, the pre-mixture and deionized water are kneaded for 30-90 minutes at a speed of 5-20 rpm in revolution and 0 rpm in rotation to obtain an intermediate mixture.

It should be noted that, in S20, while the thickener, the conductive agent, and the negative electrode material are dispersed and coated, the thickener and the negative electrode material undergo a kneading reaction.

S30, mixing the intermediate mixture, thickener and deionized water to obtain quasi-slurry.

In some embodiments, 0.1-1.0 parts by weight of thickener and 17-25 parts by weight of deionized water are added to the intermediate mixture for mixing to obtain quasi-slurry.

In some embodiments, the intermediate mixture, thickener and deionized water are mixed for 30-90 minutes at a speed of 15-30 rpm in revolution and 1200-2000 rpm in rotation to obtain quasi-slurry.

Since the thickener can neutralize the alkaline negative electrode material, the alkalinity of the quasi-slurry in the process of preparing the negative electrode slurry is at a normal level (PH = 7.5 ~ 9.0), avoiding the high alkalinity of the binder Demulsification and agglomeration occur, thereby avoiding abnormalities in the processing process caused by the negative electrode slurry settling.

S40, mixing the quasi-slurry and the binder to obtain negative electrode slurry.

In some embodiments, 0.5-3.5 parts of binder are added to the quasi-slurry and mixed to obtain negative electrode slurry.

In some embodiments, the quasi-slurry and the binder are mixed for 15-60 minutes at a speed of 15-30 rpm in revolution and 500-1500 rpm in rotation to obtain negative electrode slurry.

In the negative electrode slurry, the binder exists stably and is uniformly dispersed, and the obtained negative electrode slurry has stable viscosity and is not easy to settle.

In some embodiments, after S40, it may also include:

The negative electrode slurry is coated, dried and made into sheets to obtain the negative electrode of the sodium ion secondary battery.

In the preparation method of the negative electrode slurry provided by the embodiments of the present invention, in the high molecular polymer of the thickener, _R1 is a branched chain structure with 1-10 C atoms at the end of -COOH, and _R2 is 1-10 C atoms. The end of the atom is a branched chain structure of an acidic group, _R3 is a branched structure with 1-10 C atoms at the end of a _-COOR4 ester group, _R4 is a saturated alkane with 1-5 carbon atoms, and , 70%≤x≤95%, 0%≤y≤10%, 5%≤z≤30%, that is, the main chain structure of the thickener is a stable organic hydrocarbon chain, which will not break the chain when encountering high alkali reaction, thereby ensuring the stability of the entire macromolecular chain, thereby ensuring the stability of the dispersion system of the negative electrode slurry.

In addition, the pH value of the 1 wt% aqueous solution of the thickener in the negative electrode slurry provided by the invention is 1.0 to 3.0, while the pH value of the 1 wt% aqueous solution containing -COOH acidic groups in carboxymethylcellulose (CMC) is 6.5 to 6.5. 8.0, therefore, the ester group in the thickener provided by the present invention can enhance the compatibility with the hard carbon negative electrode, without additional use of acidic neutralizer, neutralization reaction can occur with the basic negative electrode material, so that the negative electrode can be prepared The alkalinity of the quasi-slurry in the slurry process is at a normal level (PH=7.5-9.0), which avoids the demulsification and agglomeration of the binder due to high alkalinity, thereby avoiding the abnormality of the processing process caused by the negative electrode slurry settling.

In addition, since no additional acid neutralizer is used, the production process of the negative electrode slurry can be simplified, and the acid neutralizer is omitted, which reduces the production cost of the negative electrode slurry, and at the same time increases the proportion of negative electrode materials, thereby increasing the concentration of sodium ions. The energy density of the battery. Moreover, the thickener with a certain acidity can neutralize the alkalinity of the quasi-slurry to a normal level, therefore, the selection range of the binder can be increased, the manufacturing cost of the sodium-ion battery can be further reduced, and it is beneficial to promote the development of the sodium-ion battery. industrial application.

In a third aspect, an embodiment of the present invention provides a sodium ion battery, including a positive electrode sheet, a separator, and a negative electrode sheet. The positive electrode sheet, separator, and negative electrode sheet are stacked or nested in sequence; the material of the negative electrode sheet is the embodiment of the present application. Any negative electrode slurry provided.

In some embodiments, the positive electrode active material used in the positive electrode sheet includes layered oxides; the negative electrode material used in the negative electrode sheet includes hard carbon.

In some embodiments, the positive electrode sheet can be prepared by the following steps, fully stirring the positive electrode active material layered oxide, the binder PVDF, and the conductive agent SP in a N-methylpyrrolidone solvent system at a mass ratio of 92:4:4 After mixing evenly, it is coated on an aluminum foil, dried, and cold-pressed to obtain a positive electrode sheet.

In some embodiments, the negative electrode sheet can be prepared through the following steps: the negative electrode slurry provided in the embodiment of the present application is coated, dried, and sheeted to obtain the negative electrode sheet.

The negative electrode sheet and the positive electrode sheet are then laminated (or wound), packaged, liquid injected, activated, formed, constant volume, Degas pumped package, folded, glued or dripped, and appearance inspection to obtain a sodium-ion battery. The embodiment of the present application does not limit each specific process for preparing a sodium ion battery from the negative electrode sheet and the positive electrode sheet.

In order to better understand the present invention, the preparation method of the negative electrode slurry provided by the present invention will be described in detail below with multiple examples.

Example 1

Step 100, adding sodium dodecylsulfonate to acrylate at a weight ratio of 0.001:1 into deionized water, mixing at room temperature to obtain a uniform pre-emulsion; at a temperature of 60°C, remove the pre-emulsion in a nitrogen atmosphere Oxygen in; Then, drop ammonium persulfate aqueous solution, the mass ratio of sodium dodecylsulfonate and ammonium persulfate is 1:0.005, make sodium dodecylsulfonate and acrylate polymerize for 1h, and the precipitation increases Thickener colloids are filtered, dried and crushed to obtain the finished thickener.

In step 200, add 0.2 parts by weight of thickener, 0.5 parts by weight of conductive carbon black and 20 parts by weight of hard carbon into a mixing tank and mix for 5 minutes. During mixing, the mixing tank revolves at 10 rpm and rotates at 500 rpm to obtain a premix.

Wherein, the thickener includes an organic high molecular polymer whose structural unit in the molecular formula is -(CH ₂ -CHCOOH) _0.95 -(CH ₂ -CHCOOCH ₃ ) _0.05 -.

Step 300, mix 23 parts by weight of deionized water into the premix for 30 minutes at a speed of 5 rpm and 0 rpm, so that the thickener, conductive carbon black and hard carbon are dispersed and coated, and have a certain acidity. The thickener and the basic hard carbon can undergo a neutralization reaction to obtain an intermediate mixture.

Step 400, add 0.1 parts by weight of thickener and 17 parts by weight of deionized water to the intermediate mixture, and mix for 30 minutes at a speed of 15 rpm in revolution and 1200 rpm in rotation, and further disperse the components evenly to form a fluid solid-liquid suspension At the same time, the acidic thickener and the basic hard carbon continue to neutralize and react to obtain quasi-slurry.

Through steps 300 and 400, the thickener can always maintain the thickening properties, and also complete the neutralization reaction with hard carbon, to prepare a product with uniform dispersion of components, stable solid-liquid phase, and normal alkalinity (PH=7.5-9.0 ) quasi-slurry.

In step 500, 0.5 parts by weight of styrene-butadiene rubber is added to the quasi-slurry obtained in step 400, and mixed for 15 minutes at a speed of 15 rpm in revolution and 500 rpm in rotation, so that the binder is stably present and uniformly dispersed, and a slurry with stable viscosity and not easy to settle is prepared. negative electrode slurry.

In step 600, the negative electrode slurry obtained in step 500 is coated, dried, and sheeted to obtain negative electrode sheets.

In step 700, the negative electrode sheet is laminated (or wound), encapsulated, injected with liquid, activated, formed, fixed to volume, packaged with Degas pumping, folded, glued or dripped to obtain a sodium ion battery.

Example 2

In step 100, the weight ratio of sodium dodecylsulfonate to acrylate is 0.005:1, add deionized water, mix at room temperature to obtain a uniform pre-emulsion; at a temperature of 65°C, remove the pre-emulsion in a nitrogen atmosphere Oxygen; Then, drop ammonium persulfate aqueous solution, the mass ratio of ammonium persulfate and acrylate is 0.008:1, make sodium dodecylsulfonate and acrylate polymerize for 1.5h, and precipitate thickener colloids, After pressure filtration, drying and crushing, the finished thickener is obtained.

Step 200, add 0.3 parts by weight of thickener, 1.0 parts by weight of conductive carbon black and 25 parts by weight of hard carbon into the mixing tank and mix for 6 minutes. During mixing, the mixing tank revolves at 12 rpm and rotates at 550 rpm to obtain a premix.

Wherein, the thickener includes an organic high molecular polymer whose structural unit in the molecular formula is -(CH ₂ -CHCOOH) _0.95 -(CH ₂ -CHCOOCH ₃ ) _0.05 -.

Step 300, mix 25 parts by weight of deionized water into the premix for 40 minutes at a speed of 8 rpm in revolution and 0 rpm in rotation, so that the thickener, conductive carbon black and hard carbon are dispersed and coated, and have a certain acidic thickener. The thickener and the basic hard carbon can undergo a neutralization reaction to obtain an intermediate mixture.

Step 400, add 0.3 parts by weight of thickener and 18 parts by weight of deionized water to the intermediate mixture, and mix for 40 minutes at a speed of 18 rpm in revolution and 1300 rpm in rotation, and the components are further dispersed evenly to form a fluid solid-liquid suspension At the same time, the acidic thickener and the basic hard carbon continue to neutralize and react to obtain quasi-slurry.

Through steps 300 and 400, the thickener can always maintain the thickening properties, and also complete the neutralization reaction with hard carbon, to prepare a product with uniform dispersion of components, stable solid-liquid phase, and normal alkalinity (PH=7.5-9.0 ) quasi-slurry.

In step 500, 1.0 parts by weight of styrene-butadiene rubber is added to the quasi-slurry obtained in step 400, and mixed for 20 minutes at a speed of 18 rpm in revolution and 600 rpm in rotation, so that the binder is stably present and uniformly dispersed, and a slurry with stable viscosity and not easy to settle is prepared. negative electrode slurry.

In step 600, the negative electrode slurry obtained in step 500 is coated, dried, and sheeted to obtain negative electrode sheets.

In step 700, the negative electrode sheet is laminated (or wound), encapsulated, injected with liquid, activated, formed, fixed to volume, packaged with Degas pumping, folded, glued or dripped to obtain a sodium ion battery.

Example 3

In step 100, the weight ratio of sodium dodecylsulfonate to acrylate is 0.01:1, adding to deionized water, mixing at room temperature to obtain a uniform pre-emulsion; at a temperature of 70°C, remove the pre-emulsion in a nitrogen atmosphere Oxygen; Then, drop ammonium persulfate aqueous solution, the mass ratio of ammonium persulfate and acrylate is 0.01:1, make sodium dodecylsulfonate and acrylate undergo polymerization reaction for 2 hours, and precipitate thickener colloids, after Press filtration, drying and crushing to obtain the finished thickener.

Step 200, add 0.5 parts by weight of thickener, 1.5 parts by weight of conductive material and 30 parts by weight of hard carbon into the mixing tank and mix for 7 minutes. During mixing, the mixing tank revolves at 15 rpm and rotates at 600 rpm to obtain a premix.

Wherein, the thickener includes an organic high molecular polymer whose structural unit in the molecular formula is -(CH ₂ -CHCOOH) _0.80 -(CH ₂ -CHCOOCH ₃ ) _0.20 -.

Step 300, mix 28 parts by weight of deionized water into the premix for 50 minutes at a speed of 10 rpm in revolution and 0 rpm in rotation, so that the thickener, conductive carbon black and hard carbon are dispersed and coated, and have a certain acidic thickener. The thickener and the basic hard carbon can undergo a neutralization reaction to obtain an intermediate mixture.

Step 400, add 0.5 parts by weight of thickener and 20 parts by weight of deionized water to the intermediate mixture, and mix for 60 minutes at a speed of 20 rpm in revolution and 1500 rpm in rotation, and the components are further dispersed evenly to form a fluid solid-liquid suspension At the same time, the acidic thickener and the basic hard carbon continue to neutralize and react to obtain quasi-slurry.

Through steps 300 and 400, the thickener can always maintain the thickening properties, and also complete the neutralization reaction with hard carbon, to prepare a product with uniform dispersion of components, stable solid-liquid phase, and normal alkalinity (PH=7.5-9.0 ) quasi-slurry.

In step 500, 1.5 parts by weight of styrene-butadiene rubber is added to the quasi-slurry obtained in step 400, and mixed for 30 minutes at a speed of 20 rpm in revolution and 800 rpm in rotation, so that the binder is stably present and uniformly dispersed, and a slurry with stable viscosity and not easy to settle is prepared. negative electrode slurry.

In step 600, the negative electrode slurry obtained in step 500 is coated, dried, and sheeted to obtain negative electrode sheets.

In step 700, the negative electrode sheet is laminated (or wound), encapsulated, injected with liquid, activated, formed, fixed to volume, packaged with Degas pumping, folded, glued or dripped to obtain a sodium ion battery.

Example 4

In step 100, the weight ratio of sodium dodecylsulfonate to acrylate is 0.1:1, add deionized water, mix at room temperature to obtain a uniform pre-emulsion; remove the pre-emulsion in a nitrogen atmosphere at a temperature of 80°C Oxygen; Then, drop ammonium persulfate aqueous solution, the mass ratio of ammonium persulfate and acrylate is 0.012:1, make sodium dodecylsulfonate and acrylate polymerize for 3 hours, precipitate thickener colloids, after Press filtration, drying and crushing to obtain the finished thickener.

Step 200, add 0.8 parts by weight of thickener, 2.0 parts by weight of conductive carbon black and 40 parts by weight of hard carbon into the mixing tank and mix for 8 minutes. During mixing, the mixing tank revolves at 18 rpm and rotates at 700 rpm to obtain a premix.

Wherein, the thickener includes an organic polymer whose structural unit in the molecular formula is -(CH ₂ -CHCOOH) _0.80 -(CH ₂ -CHCOOCH ₃ ) _0.20 -.

Step 300, mix 30 parts by weight of deionized water into the premix for 70 minutes at a speed of 12 rpm in revolution and 0 rpm in rotation, so that the thickener, conductive carbon black and hard carbon are dispersed and coated, and have a certain acidic thickener. The thickener and the basic hard carbon can undergo a neutralization reaction to obtain an intermediate mixture.

Step 400, add 0.7 parts by weight of thickener and 21 parts by weight of deionized water to the intermediate mixture, and mix for 70 minutes at a speed of 23 rpm in revolution and 1600 rpm in rotation, and the components are further dispersed evenly to form a fluid solid-liquid suspension At the same time, the acidic thickener and the basic hard carbon continue to neutralize and react to obtain quasi-slurry.

Through steps 300 and 400, the thickener can always maintain the thickening properties, and also complete the neutralization reaction with hard carbon, to prepare a product with uniform dispersion of components, stable solid-liquid phase, and normal alkalinity (PH=7.5-9.0 ) quasi-slurry.

In step 500, 2.5 parts by weight of styrene-butadiene rubber is added to the quasi-slurry obtained in step 400, and mixed for 40 minutes at a speed of 25 rpm in revolution and 1000 rpm in rotation, so that the binder is stably present and uniformly dispersed, and a slurry with stable viscosity and not easy to settle is prepared. negative electrode slurry.

In step 600, the negative electrode slurry obtained in step 500 is coated, dried, and sheeted to obtain negative electrode sheets.

In step 700, the negative electrode sheet is laminated (or wound), encapsulated, injected with liquid, activated, formed, fixed to volume, packaged with Degas pumping, folded, glued or dripped to obtain a sodium ion battery.

Example 5

Step 100, the weight ratio of sodium dodecylsulfonate to acrylate is 0.1:1, add deionized water, mix at room temperature to obtain a uniform pre-emulsion; at a temperature of 85 ° C, remove the pre-emulsion in a nitrogen atmosphere Oxygen; Then, drop ammonium persulfate aqueous solution, the mass ratio of ammonium persulfate and acrylate is 0.013:1, make sodium dodecylsulfonate and acrylate polymerize for 3.5h, and precipitate thickener colloids, After pressure filtration, drying and crushing, the finished thickener is obtained.

Step 200, add 0.9 parts by weight of thickener, 2.5 parts by weight of conductive carbon black and 45 parts by weight of hard carbon into the mixing tank and mix for 9 minutes. During mixing, the mixing tank revolves at 20 rpm and rotates at 800 rpm to obtain a premix.

Wherein, the thickener includes an organic high molecular polymer whose structural unit in the molecular formula is -(CH ₂ -CHCOOH) _0.70 -(CH ₂ -CHSO ₃ H) _0.10 -(CH ₂ -CHCOOCH ₃ ) _0.20 -.

Step 300, mix 32 parts by weight of deionized water into the premix for 80 minutes at a speed of 15 rpm in revolution and 0 rpm in rotation, so that the thickener, conductive carbon black and hard carbon are dispersed and coated, and have a certain acidity. The thickener and the basic hard carbon can undergo a neutralization reaction to obtain an intermediate mixture.

Step 400, add 0.9 parts by weight of thickener and 23 parts by weight of deionized water to the intermediate mixture, and mix for 80 minutes at a speed of 25 rpm in revolution and 1800 rpm in rotation, and the components are further dispersed evenly to form a fluid solid-liquid suspension At the same time, the acidic thickener and the basic hard carbon continue to neutralize and react to obtain quasi-slurry.

Through steps 300 and 400, the thickener can always maintain the thickening properties, and also complete the neutralization reaction with hard carbon, to prepare a product with uniform dispersion of components, stable solid-liquid phase, and normal alkalinity (PH=7.5-9.0 ) quasi-slurry.

In step 500, 3.0 parts by weight of styrene-butadiene rubber is added to the quasi-slurry obtained in step 400, and mixed for 50 minutes at a speed of 28 rpm in revolution and 1200 rpm in rotation, so that the binder is stably present and uniformly dispersed, and a slurry with stable viscosity and not easy to settle is prepared. negative electrode slurry.

In step 600, the negative electrode slurry obtained in step 500 is coated, dried, and sheeted to obtain negative electrode sheets.

In step 700, the negative electrode sheet is laminated (or wound), encapsulated, injected with liquid, activated, formed, fixed to volume, packaged with Degas pumping, folded, glued or dripped to obtain a sodium ion battery.

Example 6

Step 100, the weight ratio of sodium dodecyl sulfonate to acrylate is 0.15:1, add deionized water, mix at room temperature to obtain a uniform pre-emulsion; at a temperature of 90°C, remove the pre-emulsion in a nitrogen atmosphere Oxygen; Then, drip ammonium persulfate aqueous solution, the mass ratio of ammonium persulfate and acrylate is 0.015:1, make sodium dodecylsulfonate and acrylate undergo polymerization reaction for 4h, precipitate thickener micelle, pass Press filtration, drying and crushing to obtain the finished thickener.

Step 200, add 1.0 parts by weight of thickener, 3.0 parts by weight of conductive carbon black and 50 parts by weight of hard carbon into the mixing tank and mix for 10 minutes. During mixing, the mixing tank revolves at 25 rpm and rotates at 1000 rpm to obtain a premix.

Wherein, the thickener includes an organic high molecular polymer whose structural unit in the molecular formula is -(CH ₂ -CHCOOH) _0.70 -(CH ₂ -CHSO ₃ H) _0.10 -(CH ₂ -CHCOOCH ₃ ) _0.20 -.

Step 300, mix 35 parts by weight of deionized water into the premix for 90 minutes at a speed of 20 rpm in revolution and 0 rpm in rotation, so that the thickener, conductive carbon black and hard carbon are dispersed and coated, and have a certain acidic thickener. The thickener and the basic hard carbon can undergo a neutralization reaction to obtain an intermediate mixture.

Step 400, add 1.0 parts by weight of thickener and 25 parts by weight of deionized water to the intermediate mixture, and mix for 90 minutes at a speed of 30 rpm in revolution and 2000 rpm in rotation, and further disperse the components evenly to form a fluid solid-liquid suspension At the same time, the acidic thickener and the basic hard carbon continue to neutralize and react to obtain quasi-slurry.

Through steps 300 and 400, the thickener can always maintain the thickening properties, and also complete the neutralization reaction with hard carbon, to prepare a product with uniform dispersion of components, stable solid-liquid phase, and normal alkalinity (PH=7.5-9.0 ) quasi-slurry.

In step 500, 3.5 parts by weight of styrene-butadiene rubber is added to the quasi-slurry obtained in step 400, and mixed for 60 minutes at a speed of 30 rpm in revolution and 1500 rpm in rotation, so that the binder is stably present and uniformly dispersed, and a slurry with stable viscosity and not easy to settle is prepared. negative electrode slurry.

In step 600, the negative electrode slurry obtained in step 500 is coated, dried, and sheeted to obtain negative electrode sheets.

In step 700, the negative electrode sheet is laminated (or wound), encapsulated, injected with liquid, activated, formed, fixed to volume, packaged with Degas pumping, folded, glued or dripped to obtain a sodium ion battery.

Comparative example 1

Step 100, add 1.0 parts by weight of thickener, 3.0 parts by weight of conductive carbon black and 50 parts by weight of hard carbon into the mixing tank and mix for 10 minutes. During mixing, the mixing tank revolves at 25 rpm and rotates at 1000 rpm to obtain a premix. Wherein, the thickener adopts water-soluble cellulose ether—sodium carboxymethyl cellulose (CMC).

Step 200, mix 35 parts by weight of deionized water into the premix for 90 minutes at a speed of 20 rpm in revolution and 0 rpm in rotation, and disperse and coat the thickener, conductive carbon black and hard carbon to obtain an intermediate mixture.

Step 300, add 1.0 parts by weight of thickener and 25 parts by weight of deionized water to the intermediate mixture, and mix for 90 minutes at a speed of 30 rpm in revolution and 2000 rpm in rotation, and further disperse the components evenly to form a fluid solid-liquid suspension system to obtain quasi-slurry.

In step 400, 3.5 parts by weight of styrene-butadiene rubber was added to the quasi-slurry obtained in step 400, and mixed for 60 minutes at a speed of 30 rpm in revolution and 1500 rpm in rotation to obtain negative electrode slurry.

Comparative example 2

Step 100, add 1.0 parts by weight of thickener, 3.0 parts by weight of conductive carbon black and 50 parts by weight of hard carbon into the mixing tank and mix for 10 minutes. During mixing, the mixing tank revolves at 25 rpm and rotates at 1000 rpm to obtain a premix. Among them, the main chain of the thickener is a thickener of organic hydrocarbon chain - polyacrylic acid.

Step 200, mix 35 parts by weight of deionized water into the premix for 90 minutes at a speed of 20 rpm in revolution and 0 rpm in rotation to obtain an intermediate mixture.

In step 300, 1.0 parts by weight of thickener and 25 parts by weight of deionized water are added to the intermediate mixture, and mixed for 90 minutes at a speed of 30 rpm in revolution and 2000 rpm in rotation, and the components are further uniformly dispersed to obtain quasi-slurry.

In step 400, 3.5 parts by weight of styrene-butadiene rubber was added to the quasi-slurry obtained in step 400, and mixed for 60 minutes at a speed of 30 rpm in revolution and 1500 rpm in rotation to obtain negative electrode slurry.

The negative electrode slurries obtained in Examples 1 to 4, and the negative electrode slurries obtained in Comparative Example 1 and Comparative Example 2 were selected for stability testing, and the stability test results are shown in FIG. 2 . In Fig. 2, the abscissa represents the length of time in hours (h); the ordinate represents the viscosity in mPa·s.

It should be noted that the stability test results of Example 5 and Example 6 are basically similar to the test results of Example 4. In order to show the stability more clearly, only Examples 1 to 4, Comparative Example 1 and The stability results of Comparative Example 2.

The stability test was carried out at room temperature. It can be seen from FIG. 2 that the viscosity fluctuations of the negative electrode slurries obtained in Examples 1 to 4 are smaller with the prolongation of time, indicating that these negative electrode slurries have good stability. The viscosity of Comparative Example 1 and Comparative Example 2 decreased rapidly with the prolongation of time. It can be known from the stability test results in FIG. 2 that the negative electrode slurry provided by the embodiment of the present invention has higher stability.

It should be clear that the present invention is not limited to the specific configurations and processes described in the above embodiments and shown in the drawings. For the convenience and brevity of description, detailed descriptions of known methods are omitted here, and the specific working processes of the above-described systems, modules, and units can refer to the corresponding processes in the foregoing method embodiments, and are not repeated here.

The apparatus embodiments described above are merely illustrative, where units illustrated as separate components may or may not be physically separate. Part or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. It can be understood and implemented by those skilled in the art without any creative effort.

It can be understood that, the above embodiments are only exemplary embodiments adopted for illustrating the principle of the present invention, but the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also regarded as the protection scope of the present invention.

Claims (12)

1. The negative electrode slurry is characterized by comprising a binder, a thickener and a negative electrode material, wherein the thickener comprises a high molecular polymer of a structural unit shown in a formula (I):

wherein R is ₁ A branched structure of 1-10C atoms ending in-COOH, R ₂ A branched structure having 1 to 10C atoms and terminating in an acidic group, R ₃ From 1 to 10C atoms terminated by-COOR ₄ Branched structure of ester group, R ₄ Saturated alkane with 1-5 carbon atoms, and x is more than or equal to 70% and less than or equal to 95%, y is more than or equal to 0% and less than or equal to 10%, and z is more than or equal to 5% and less than or equal to 30%.

2. The anode slurry according to claim 1, wherein the acidic group comprises-SO ₃ H, and/or the negative electrode material comprises hard carbon.

3. The negative electrode slurry according to claim 1 or 2, wherein,

0.3-2.0 parts by weight of thickener, 20-50 parts by weight of negative electrode material and 0.5-3.5 parts by weight of binder.

4. The negative electrode slurry according to claim 3, further comprising deionized water 40 to 60 parts by weight and a conductive agent 0.5 to 3.0 parts by weight.

5. The negative electrode slurry according to claim 4, wherein,

the binder comprises any one or more of polyvinylidene fluoride, acrylonitrile multipolymer, perfluorinated sulfonic acid resin, sodium carboxymethyl cellulose, styrene-butadiene rubber and polymethyl acrylate;

and/or the conductive agent comprises any one or more of conductive carbon black, single-walled carbon nanotubes, multi-walled carbon nanotubes, graphene, conductive graphite, and carbon fibers.

6. A method for producing a negative electrode slurry, comprising:

mixing a thickener, a conductive agent and a negative electrode material to obtain a premix; wherein the thickener comprises a high molecular polymer of a structural unit shown in a formula (I):

wherein R is ₁ A branched structure of 1-10C atoms ending in-COOH, R ₂ A branched structure having 1 to 10C atoms and terminating in an acidic group, R ₃ From 1 to 10C atoms terminated by-COOR ₄ Branched structure of ester group, R ₄ Saturated alkane with 1-5 carbon atoms, and x is more than or equal to 70% and less than or equal to 95%, y is more than or equal to 0% and less than or equal to 10%, and z is more than or equal to 5% and less than or equal to 30%;

Mixing the premix with deionized water, and kneading the thickener and the negative electrode material to obtain an intermediate mixture;

mixing the intermediate mixture, the thickener and the deionized water to obtain a quasi-slurry;

and mixing the quasi-slurry with a binder to obtain the negative electrode slurry.

7. The method for producing a negative electrode slurry according to claim 6, wherein 0.3 to 2.0 parts by weight of the thickener, 20 to 50 parts by weight of the negative electrode material, and 0.5 to 3.5 parts by weight of the binder are mixed to obtain the premix;

and/or adding 23-35 parts by weight of the deionized water to the pre-mixture for mixing to obtain the intermediate mixture;

and/or adding 0.1-1.0 parts by weight of the thickener and 17-25 parts by weight of the deionized water to the intermediate mixture to mix, thereby obtaining the quasi-slurry;

and/or adding 0.5-3.5 parts of binder into the quasi-slurry and mixing to obtain the negative electrode slurry.

8. The method for producing a negative electrode slurry according to claim 6, wherein the thickener, the conductive agent and the negative electrode material are mixed at a revolution speed of 10 to 25rpm and a rotation speed of 500 to 1000rpm for 5 to 10 minutes to obtain the premix;

And/or, the pre-mixture and the deionized water are subjected to kneading reaction for 30-90min at a revolution speed of 5-20rpm and a rotation speed of 0rpm, so as to obtain the intermediate mixture;

and/or mixing the intermediate mixture, the thickener and the deionized water for 30-90min at a revolution speed of 15-30rpm and a rotation speed of 1200-2000rpm to obtain the quasi-slurry;

and/or mixing the quasi-slurry and the binder for 15-60min at a revolution speed of 15-30rpm and a rotation speed of 500-1500rpm to obtain the negative electrode slurry.

9. The method for producing a negative electrode slurry according to claim 6, wherein the thickener is obtained by:

mixing deionized water, a surfactant and a monomer material to obtain a pre-emulsion;

removing oxygen from the pre-emulsion;

dripping an initiator into the pre-emulsion after deoxidization to perform polymerization reaction, and separating out the thickener colloidal particles;

and (3) treating the thickener colloidal particles to obtain the thickener.

10. The method for producing a negative electrode slurry according to claim 9, wherein the surfactant comprises one or more of sodium dodecylbenzenesulfonate, allyl ether sulfonate, polyether ammonium phosphate containing double bonds;

The monomer material comprises one or more of acrylic ester, acrylic acid and acrylic sulfonic acid;

the initiator comprises one or more of ammonium sulfate, sodium persulfate, dialkyl peroxide and ester peroxide.

11. The method for producing a negative electrode slurry according to claim 10, wherein the deionized water, the surfactant, and the monomer material are mixed at room temperature, and a mass ratio of the surfactant to the monomer material is 1:0.001-0.15;

and/or removing oxygen from the pre-emulsion in an inert gas atmosphere at a temperature of 60-90 ℃;

and/or the mass ratio of the surfactant to the initiator is 1:0.005-0.015;

and/or, the pre-emulsion is polymerized for 1-4 hours, and the thickener colloidal particles are separated out.

12. The sodium ion battery is characterized by comprising a positive plate, a separation film and a negative plate, wherein the positive plate, the separation film and the negative plate are sequentially overlapped or sequentially nested;

the negative electrode sheet is produced by the negative electrode slurry according to any one of claims 1 to 4.