A battery negative electrode slurry based on niobium-based oxide and its preparation method

Abstract

The present invention relates to the technical field of sodium-ion battery materials and specifically discloses a battery negative electrode slurry based on niobium-based oxides and a preparation method thereof. The present invention dissolves a niobium source and a metal salt in an aqueous ethanol solution or an isopropanol solution, employs a solvothermal method to prepare a niobium-based oxide precursor, and then produces the niobium-based oxide material by high-temperature calcination. The prepared niobium-based oxide exhibits excellent electrochemical properties as a sodium-ion negative electrode active material; the preparation method of the present invention is simple, low-cost, and universally applicable. Furthermore, the proposal further investigates the use of corresponding binders in the negative electrode slurry to effectively improve the electrical cycling performance of the battery negative electrode slurry.

Description

Technical Field

[0001] The present invention relates to the technical field of sodium ion battery materials, and in particular to a battery negative electrode slurry based on niobium-based oxide and a preparation method thereof. Background Art

[0002] In recent years, environmental pollution and the fossil energy crisis have triggered the rapid development of cost-effective energy storage solutions. Among them, sodium-ion batteries are considered to be a potential alternative to lithium-ion batteries due to their low cost and abundant resources. However, since the radius of Na ions (0.102nm) is larger than that of Li ions (0.076nm), the larger ion radius leads to the rapid development of electrode materials in Na + The volume expansion is obvious during the insertion and extraction process, and the electrochemical kinetics are slow. Therefore, the development of negative electrode materials with high specific energy and excellent cycle performance is an important direction in the research and development of sodium-ion batteries.

[0003] Sodium ion negative electrodes are generally obtained by coating a slurry containing negative electrode active materials on a current collector. Currently, the main negative electrode active materials are carbon-based, titanium-based, alloys and other materials. It is worth noting that niobates with a shear-type ReO3 crystal structure are considered to be extremely promising sodium ion battery negative electrode materials due to their high theoretical capacity and excellent safety. Among them, binary niobium-based oxides (M-Nb-O, M is a metal) present a stable Wadsley-Roth phase, which can quickly realize ion insertion and extraction, and have become very promising candidate materials in electrochemical energy storage systems. However, the poor intrinsic electronic conductivity of M-Nb-O negative electrode materials limits its development in energy storage devices. Although there have been some reports on improving niobium-based oxides, there is still a need to develop new niobium-based oxide systems and achieve precise control of the morphology and structure of niobium-based oxides.

[0004] In addition, in the negative electrode slurry of sodium ion batteries, the binder has side reactions during the battery charge and discharge cycle, which leads to a decrease in the capacity and rate performance of the battery material.

[0005] Based on the above situation, it is of great significance to adjust the negative electrode active material, binder, etc. to prepare a battery negative electrode slurry based on niobium-based oxide to effectively improve the cycle stability and rate performance of sodium ion batteries. Summary of the Invention

[0006] The object of the present invention is to provide a battery negative electrode slurry based on niobium-based oxide and a preparation method thereof, so as to solve the problems raised in the above background technology.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0008] A method for preparing niobium-based oxide comprises the following steps:

[0009] Step 1: dissolving a niobium source and a metal source in a solvent to obtain a mixed solution; transferring the mixed solution to a hydrothermal reactor for hydrothermal reaction; centrifuging, washing, and drying to obtain a niobium-based oxide precursor;

[0010] Step 2: calcining the niobium-based oxide precursor at 600-1200° C. for 60-240 min in an inert gas atmosphere, and naturally cooling to room temperature to obtain niobium-based oxide.

[0011] More optimally, the niobium source includes niobium oxalate or niobium pentoxide; the metal source includes metal chloride or metal acetate, and the metal species in the metal source include one or more of molybdenum, zinc, tin, and titanium.

[0012] More optimally, the molar ratio of the niobium source to the metal source is (1-1.5):1.

[0013] More optimally, in step 1, the stirring rate is 800±100 r / min, and the stirring time is 30-60 min; the hydrothermal reaction conditions are: reaction at 180±10°C for 12-30 h.

[0014] More optimally, a method for preparing niobium-based oxide prepares niobium-based oxide.

[0015] More optimally, a battery negative electrode slurry based on niobium-based oxide includes niobium-based oxide; the battery negative electrode slurry is applied to the negative electrode of a sodium ion battery.

[0016] More optimally, a method for preparing a battery negative electrode slurry based on niobium-based oxide includes the following steps: dispersing niobium-based oxide, a conductive agent, and a binder in N-methyl-2-pyrrolidone in sequence, dispersing them evenly, and obtaining a battery negative electrode slurry.

[0017] More optimally, the binder is PVDF.

[0018] In a further embodiment, the binder is a polyvinyl alcohol copolymer, and the preparation method thereof comprises the following steps:

[0019] (1) Add 5 parts of acrylamide, 6 to 9 parts of sodium p-styrenesulfonate, 0.06 to 0.08 parts of 4-hydroxy TEMPO, and 0.1 to 0.2 parts of sodium bisulfite to deionized water and mix them uniformly to obtain solution A; dissolve 0.1 to 0.2 parts of ammonium persulfate in deionized water to obtain solution B; under a nitrogen atmosphere, solution A and solution B are added dropwise at the same time, after the addition and mixing, stirred at 60 to 65° C. for 4 to 4.5 hours, and post-treated to obtain a TEMPO-terminated low-molecular copolymer;

[0020] (2) adding 10 parts by weight of a TEMPO-terminated low-molecular-weight copolymer and 6 to 6.5 parts of basic alumina to an acetonitrile-deionized water mixed solution, stirring uniformly, adding 1.5 to 2.5 parts of chloroethyl acrylate, stirring at room temperature for 48 hours, and post-treating to obtain a vinyl-terminated low-molecular-weight copolymer;

[0021] (3) Add 15 parts of polyvinyl alcohol to dimethyl sulfoxide to dissolve, add 35-45 parts of acrylonitrile and 0.12-0.15 parts of ammonium persulfate, stir and react at 60-65° C. for 1-1.5 hours, add 3-4 parts of vinyl-terminated low-molecular copolymer, continue to react for 1-2 hours, and post-treat to obtain a polyvinyl alcohol copolymer.

[0022] More optimally, the mass ratio of the niobium-based oxide, the conductive agent, and the binder is 7:2:1.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) A niobium-based oxide was prepared as a sodium ion negative electrode active material, which has excellent electrochemical properties and can be used in battery negative electrode slurry to effectively enhance the electrical cycling stability and rate performance of the sodium ion battery negative electrode.

[0025] Niobium-based oxides are prepared using a universal solvothermal method. By adjusting the ratio of the metal source to the niobium source, the hydrothermal reaction temperature and time, and the high-temperature calcination temperature and time, the morphology and structure of the niobium-based oxides can be precisely controlled, resulting in high-performance niobium-based oxides. This method is simple, low-cost, and universal, effectively enhancing its applicability in energy storage.

[0026] (2) PVDF is usually used as a binder in common batteries (such as lithium-ion batteries). However, in sodium-ion batteries, PVDF undergoes a defluorination process during the electrical cycle, resulting in poor chemical stability and a thicker NaF layer, which inhibits the capacitance and rate performance of the electrode active material, resulting in a large attenuation of the battery capacity and poor cycle performance.

[0027] Therefore, in this application, firstly, the electrical properties and stability of the negative electrode active material are improved by introducing a second metal source into the niobium-based oxide; secondly, in a further scheme, a polyvinyl alcohol copolymer is used to replace the common PVDF as a binder for the battery negative electrode slurry; it is obtained by copolymerizing polyvinyl alcohol and acrylonitrile and grafting a vinyl-terminated low-molecular copolymer. Since it is a non-fluorinated polymer, it can inhibit the formation of the NaF layer (side reaction layer).

[0028] Among them, since the heat resistance of single polyvinyl alcohol is poor, during the charge and discharge process, as the expansion stress acts, the adhesion of the negative electrode slurry layer on the current collector will decrease, resulting in an increase in resistance; therefore, it is introduced into acrylonitrile copolymer to effectively improve the stability of the polyethylene copolymer during the cycle process; and further grafted end vinyl low molecular copolymers to increase the branched structure, thereby effectively buffering the volume expansion, and effectively increasing the diffusion rate of sodium ions in the electrode, reducing the interface resistance, and effectively improving the electrical performance of the battery negative electrode; at the same time, after the grafted end vinyl low molecular copolymer chain segments, it has better adhesion, which can effectively enhance the stable mechanical properties of the negative electrode material under high-speed charge and discharge conditions, thereby improving the cycle electrical performance and rate performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0030] Figure 1 This is the XRD picture of Zn3Nb2O8;

[0031] Figure 2 This is the SEM image of Zn3Nb2O8;

[0032] Figure 3 TEM image of Zn3Nb2O8;

[0033] Figure 4 This is a cycling stability diagram of a sodium ion button cell assembled with the battery negative electrode slurry of Example 1 at a current density of 0.5 A / g;

[0034] Figure 5 This is a rate performance diagram of a sodium ion button cell assembled with the battery negative electrode slurry of Example 1;

[0035] Figure 6 for Mo 8.7 Nb 6.1 O x SEM photos of

[0036] Figure 7 This is a cycling stability diagram of a sodium ion button cell assembled with the battery negative electrode slurry of Example 2 at a current density of 0.5 A / g;

[0037] Figure 8 This is a rate performance diagram of the sodium ion button battery assembled with the battery negative electrode slurry of Example 2. DETAILED DESCRIPTION

[0038] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0039] In this embodiment, it should be noted that the raw materials involved in the present invention are purchased from manufacturers without any special restrictions, and illustratively include: acrylamide with a CAS number of 79-06-1; sodium p-styrene sulfonate with a CAS number of 2695-37-6; 4-hydroxy TEMPO with a CAS number of 2226-96-2; chloroethyl acrylate with a CAS number of 2206-89-5; polyvinyl alcohol with a degree of hydrolysis of 88.8%, model DenkaPOVAL B-05; niobium oxalate with a CAS number of 21348-59-4, molybdenum pentachloride with a CAS number of 10241-05-1, binder PVDF with a CAS number of 24937-79-9, and conductive agent Super P with a CAS number of 7440-44-0; all of which are commercially available.

[0040] Example 1: A method for preparing a battery negative electrode slurry based on niobium-based oxide, comprising the following steps:

[0041] Step 1: 2mmol niobium oxalate (C 10 H5NbO 20 ) and 2.26 mmol of zinc acetate (C4H6O4Zn) were dissolved in 60 mL of deionized water and stirred vigorously for 2 hours to obtain a mixed solution; the mixed solution was poured into a sealed autoclave and heated continuously at 180°C for 24 hours; the solution after the solvothermal reaction was centrifuged, washed, and then dried in an 80°C forced air drying oven for 12 hours to obtain a zinc niobium oxide precursor;

[0042] Step 2: The niobium-based oxide precursor is placed in a tube furnace and calcined at 950°C for 2 hours under an argon atmosphere, and then naturally cooled to room temperature to obtain niobium-based oxide (Zn3Nb2O8).

[0043] Step 3: Dissolve niobium-based oxide, conductive agent SuperP, and binder PVDF in dispersant NMP in a mass ratio of 7:2:1, and disperse them evenly to obtain a battery negative electrode slurry.

[0044] Example 2: A method for preparing a battery negative electrode slurry based on niobium-based oxide, comprising the following steps:

[0045] Step 1: 1.6 mmol niobium oxalate (C 10 H5NbO 20) and 1.8 mmol of molybdenum pentachloride (MoCl5) were dissolved in 60 mL of isopropanol and stirred vigorously for 2 hours to obtain a mixed solution; the mixed solution was poured into a sealed autoclave and heated continuously at 180°C for 30 hours; the solution after the solvothermal reaction was centrifuged and washed, and then dried in an 80°C forced air drying oven for 12 hours to obtain a molybdenum niobium oxide precursor;

[0046] Step 2: Place the niobium-based oxide precursor in a tube furnace, calcine it at 700°C for 4 hours under an argon atmosphere, and cool it naturally to room temperature to obtain niobium-based oxide (Mo 8.7 Nb 6.1 O x );

[0047] Step 3: Dissolve niobium-based oxide, conductive agent Super P, and binder PVDF in dispersant NMP in a mass ratio of 7:2:1, and disperse them evenly to obtain a battery negative electrode slurry.

[0048] Example 3: Based on Example 1, the binder is adjusted, specifically comprising the following steps:

[0049] Step 1: 2mmol niobium oxalate (C 10 H5NbO 20 ) and 2.26 mmol of zinc acetate (C4H6O4Zn) were dissolved in 60 mL of deionized water and stirred vigorously for 2 hours to obtain a mixed solution; the mixed solution was poured into a sealed autoclave and heated continuously at 180°C for 24 hours; the solution after the solvothermal reaction was centrifuged, washed, and then dried in an 80°C forced air drying oven for 12 hours to obtain a zinc niobium oxide precursor;

[0050] Step 2: The niobium-based oxide precursor is placed in a tube furnace and calcined at 950°C for 2 hours under an argon atmosphere, and then naturally cooled to room temperature to obtain niobium-based oxide (Zn3Nb2O8).

[0051] Step 3: S3.1: (1) by weight, 5 parts of acrylamide, 8 parts of sodium p-styrenesulfonate, 0.076 parts of 4-hydroxy TEMPO, and 0.15 parts of sodium bisulfite were added to deionized water and mixed evenly to obtain solution A; 0.2 parts of ammonium persulfate were dissolved in deionized water to obtain solution B; under a nitrogen atmosphere, solution A and solution B were added dropwise at the same time, after the addition and mixing, stirred at 60°C for 4 hours, and post-treated to obtain a TEMPO-terminated low-molecular copolymer; (2) by weight, 10 parts of TEMPO-terminated low-molecular copolymer were added dropwise to obtain a TEMPO-terminated low-molecular copolymer; The low molecular weight copolymer and 6.4 parts of alkaline alumina were added to a mixed solution of acetonitrile and deionized water (volume ratio of 3:1), stirred evenly, and 2 parts of chloroethyl acrylate were added, stirred at room temperature for 48 hours, and post-treated to obtain a low molecular weight copolymer with vinyl end; (3) 15 parts of polyvinyl alcohol were added to dimethyl sulfoxide and dissolved, 40 parts of acrylonitrile and 0.12 parts of ammonium persulfate were added, stirred and reacted at 60°C for 1.5 hours, 4 parts of the low molecular weight copolymer with vinyl end were added, and the reaction was continued for 2 hours, and post-treated to obtain a polyvinyl alcohol copolymer;

[0052] S3.2: Dissolve niobium-based oxide, conductive agent Super P, and polyvinyl alcohol copolymer in dispersant NMP in a mass ratio of 7:2:1, and disperse them evenly to obtain a battery negative electrode slurry.

[0053] Example 4: Based on Example 1, the binder is adjusted, specifically comprising the following steps:

[0054] Step 1: 2mmol niobium oxalate (C 10 H5NbO 20 ) and 2.26 mmol of zinc acetate (C4H6O4Zn) were dissolved in 60 mL of deionized water and stirred vigorously for 2 hours to obtain a mixed solution; the mixed solution was poured into a sealed autoclave and heated continuously at 180°C for 24 hours; the solution after the solvothermal reaction was centrifuged, washed, and then dried in an 80°C forced air drying oven for 12 hours to obtain a zinc niobium oxide precursor;

[0055] Step 2: The niobium-based oxide precursor is placed in a tube furnace and calcined at 950°C for 2 hours under an argon atmosphere, and then naturally cooled to room temperature to obtain niobium-based oxide (Zn3Nb2O8).

[0056] Step 3: S3.1: Dissolve 15 parts of polyvinyl alcohol in dimethyl sulfoxide, add 45 parts of acrylonitrile and 0.12 parts of ammonium persulfate, stir and react at 60°C for 2.5 hours, and post-treat to obtain a polyvinyl alcohol copolymer;

[0057] S3.2: Dissolve niobium-based oxide, conductive agent Super P, and polyvinyl alcohol copolymer in dispersant NMP in a mass ratio of 7:2:1, and disperse them evenly to obtain a battery negative electrode slurry.

[0058] Example 5: Based on Example 1, the binder is adjusted, specifically comprising the following steps:

[0059] Step 1: 2mmol niobium oxalate (C 10 H5NbO 20 ) and 2.26 mmol of zinc acetate (C4H6O4Zn) were dissolved in 60 mL of deionized water and stirred vigorously for 2 hours to obtain a mixed solution; the mixed solution was poured into a sealed autoclave and heated continuously at 180°C for 24 hours; the solution after the solvothermal reaction was centrifuged, washed, and then dried in an 80°C forced air drying oven for 12 hours to obtain a zinc niobium oxide precursor;

[0060] Step 2: The niobium-based oxide precursor is placed in a tube furnace and calcined at 950°C for 2 hours under an argon atmosphere, and then naturally cooled to room temperature to obtain niobium-based oxide (Zn3Nb2O8).

[0061] Step 3: S3.1: (1) by weight, 5 parts of acrylamide, 8 parts of sodium p-styrenesulfonate, 0.076 parts of 4-hydroxy TEMPO, and 0.15 parts of sodium bisulfite were added to deionized water and mixed evenly to obtain solution A; 0.2 parts of ammonium persulfate were dissolved in deionized water to obtain solution B; under a nitrogen atmosphere, solution A and solution B were added dropwise at the same time, after the addition and mixing, stirred at 60°C for 4 hours, and post-treated to obtain a TEMPO-terminated low-molecular copolymer; (2) by weight, 10 parts of TEM PO-based low molecular weight copolymer and 6.4 parts of basic alumina are added to an acetonitrile-deionized water mixed solution (volume ratio of 3:1), stirred evenly, and 2 parts of chloroethyl acrylate are added, stirred at room temperature for 48 hours, and post-treated to obtain a vinyl-terminated low molecular weight copolymer; (3) 30 parts of polyvinyl alcohol are added to dimethyl sulfoxide and dissolved, and 0.12 parts of ammonium persulfate are added, stirred and reacted at 60°C for 1.5 hours, 10 parts of vinyl-terminated low molecular weight copolymer are added, and the reaction is continued for 2 hours, and post-treated to obtain a polyvinyl alcohol copolymer;

[0062] S3.2: Dissolve niobium-based oxide, conductive agent Super P, and polyvinyl alcohol copolymer in dispersant NMP in a mass ratio of 7:2:1, and disperse them evenly to obtain a battery negative electrode slurry.

[0063] Testing: The battery negative electrode slurry prepared in the following examples was coated onto aluminum foil and dried in a vacuum oven at 80°C for 12 hours to produce an electrode sheet. CR2032 button cells were assembled in a glove box under argon using a GF / D glass microfiber filter membrane as the separator and 1.0 mol / L NaPF6 dissolved in diglyme (DME) as the electrolyte. The cells were tested using a Land (CT2001A) battery testing system over a voltage range of 0.01-3.00 V, and related electrical performance measurements were performed.

[0064] Test result 1: (1) The XRD patterns of the niobium-based oxides (Zn3Nb2O8) prepared in Example 1, Example 3, Example 4 and Example 5 are as follows: Figure 1 As shown in the SEM images Figure 2 As shown in the TEM image Figure 3 (2) The cyclic stability diagram in Example 1 is as shown in FIG. Figure 4 As shown, at a current density of 0.5 A / g, the capacity retention rate after 400 cycles is 94.5%, and the rate performance is as follows Figure 5 (3) The niobium-based oxide (Mo) prepared in Example 2 8.7 Nb 6.1 O x )'s SEM such as Figure 6 ; Cyclic stability diagram as shown Figure 7 As shown, the rate performance is as follows Figure 8 shown.

[0065] Test result 2: At a current density of 0.5 A / g, the battery negative electrode slurries in Examples 1, 3, 4, and 5 were used in button batteries. The cycle retention rates after 1000 cycles are shown in the following table:

[0066] Example 1 Example 3 Example 4 Example 5 Capacity retention rate (%) 82.3 91.6 86.1 84.2

[0067] Results: The data in the above table show that: since the fluorine-containing binder PVDF was further replaced by a polyvinyl alcohol copolymer in Example 3, the influence of the by-product NaF on the active material was solved, thereby effectively improving its cycle life; in Example 4, since the low-molecular-weight copolymer with no grafted end vinyl was used, the stress buffering decreased, thereby reducing the cycle retention rate; in Example 5, since the single grafted end vinyl low-molecular-weight copolymer had excessive molecular entanglement, the adhesion decreased and the performance declined.

[0068] In summary, the niobium-based oxide prepared in this application has excellent electrochemical properties as a sodium ion negative electrode material, and the polyvinyl alcohol copolymer further prepared as a binder can effectively enhance the electrical cycling performance of the battery negative electrode slurry.

[0069] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0070] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for preparing a battery negative electrode slurry based on niobium-based oxide, characterized in that: The battery negative electrode slurry is a sodium ion battery negative electrode slurry; the preparation method comprises the following steps: dispersing niobium-based oxide, a conductive agent, and a binder in N-methyl-2-pyrrolidone in sequence, and dispersing them uniformly to obtain a battery negative electrode slurry; The preparation of the niobium-based oxide comprises the following steps: (1) dissolving a niobium source and a metal source in a solvent to obtain a mixed solution; transferring the mixed solution to a hydrothermal reactor for hydrothermal reaction; centrifuging, washing, and drying to obtain a niobium-based oxide precursor; (2) calcining the niobium-based oxide precursor at a high temperature of 600 to 1200° C. for 60 to 240 minutes under an inert gas atmosphere, and naturally cooling the niobium-based oxide to room temperature to obtain a niobium-based oxide; The niobium source includes niobium oxalate or niobium pentoxide; the metal source includes a metal chloride salt or a metal acetate salt, and the metal species in the metal source include one or two of molybdenum and zinc; the molar ratio of the niobium source to the metal source is (1-1.5):1; The binder is a polyvinyl alcohol copolymer, and the preparation method comprises the following steps: (1) adding 5 parts of acrylamide, 6 to 9 parts of sodium p-styrene sulfonate, 0.06 to 0.08 parts of 4-hydroxy TEMPO, and 0.1 to 0.2 parts of sodium bisulfite to deionized water and mixing them uniformly to obtain solution A; dissolving 0.1 to 0.2 parts of ammonium persulfate in deionized water to obtain solution B; adding solution A and solution B dropwise at the same time under a nitrogen atmosphere, stirring and reacting at 60 to 65° C. for 4 to 4.5 hours after the addition and mixing, and post-treating to obtain a TEMPO-terminated low-molecular copolymer; (2) adding 1 part of acrylamide, 6 to 9 parts of sodium p-styrene sulfonate, 0.06 to 0.08 parts of 4-hydroxy TEMPO, and 0.1 to 0.2 parts of sodium bisulfite to deionized water and mixing them uniformly to obtain solution A; dissolving 0.1 to 0.2 parts of ammonium persulfate in deionized water and obtaining solution B; adding solution A and solution B dropwise at the same time under a nitrogen atmosphere, stirring and reacting at 60 to 65° C. for 4 to 4.5 hours after the addition and mixing, and post-treating to obtain a TEMPO-terminated low-molecular copolymer; 0 parts of TEMPO-terminated low molecular weight copolymer and 6-6.5 parts of alkaline alumina are added to an acetonitrile-deionized water mixed solution, stirred evenly, 1.5-2.5 parts of chloroethyl acrylate are added, stirred at room temperature for 48 hours, and post-treated to obtain a vinyl-terminated low molecular weight copolymer; (3) 15 parts of polyvinyl alcohol are added to dimethyl sulfoxide to dissolve, 35-45 parts of acrylonitrile and 0.12-0.15 parts of ammonium persulfate are added, stirred and reacted at 60-65°C for 1-1.5 hours, 3-4 parts of vinyl-terminated low molecular weight copolymer are added, the reaction is continued for 1-2 hours, and post-treated to obtain a polyvinyl alcohol copolymer.

2. The method for preparing a battery negative electrode slurry based on niobium-based oxide according to claim 1, characterized in that: In step 1, the stirring rate is 800±100 r / min, and the stirring time is 30 to 60 min; the hydrothermal reaction conditions are: reaction at 180±10° C. for 12 to 30 h.

3. The method for preparing a battery negative electrode slurry based on niobium-based oxide according to claim 1, characterized in that: The mass ratio of the niobium-based oxide, the conductive agent, and the binder is 7:2:

1.

4. A battery negative electrode slurry prepared according to the method for preparing a battery negative electrode slurry based on niobium-based oxide according to any one of claims 1 to 3.

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