Preparation Method and Application of Graphite Anode Material for New Energy Batteries

Abstract

The present invention provides a preparation method and application of a graphite anode material for new energy batteries, belonging to the technical field of lithium batteries. The preparation method comprises the following steps: (1) preparing pretreated graphite powder; (2) mixing polyethylene glycol, calcium chloride and water in a weight ratio of (3-6):1:(10-13), stirring evenly to obtain a mixed solution A; adding the pretreated graphite powder into the mixed solution A, continuously adding a surfactant, and stirring for 4-6 h to obtain a mixed solution B; (3) heating the mixed solution B to 80-85 °C for evaporation until it becomes a gel-like substance, and vacuum drying the gel-like substance to obtain a precursor; (4) calcining the precursor in a nitrogen atmosphere, and after the calcination is completed, pulverizing and sieving to obtain a graphite anode material for new energy batteries. The graphite anode material prepared by the present invention can improve the initial discharge specific capacity of lithium batteries, has high rate performance and good high-temperature resistance effect.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium batteries, and particularly relates to a preparation method and application of a graphite negative electrode material for new energy batteries. Background Art

[0002] With the progress of society and the growth of people's energy demand, the greenhouse effect and environmental pollution problems brought about by the use of traditional energy are becoming increasingly prominent. Therefore, the development and application of new energy are particularly urgent. As an energy technology that has been developed for many years, lithium-ion batteries have become a key research area in academia due to their environmental protection characteristics and relatively low recycling costs.

[0003] The negative electrode is one of the core components of a lithium-ion battery, and the performance indicators such as the capacity, charge and discharge rate, and service life of the battery largely depend on the selection of the negative electrode material. To improve the overall electrochemical performance of lithium-ion batteries, it is usually necessary to modify and optimize the negative electrode material.

[0004] Existing modification methods generally include: coating, blending, special morphology design, doping, etc. In the prior art, the hard carbon coating method often directly cures and pyrolyzes hard carbon materials (such as polystyrene, etc.) and graphite materials to achieve the coating of graphite materials, which requires long-term high-temperature stirring and it is difficult to ensure uniform coating. When uniform coating cannot be achieved, the rate performance will be significantly reduced. And currently, the actual initial discharge specific capacity of most lithium battery graphite negative electrode materials on the market does not exceed 350 mAh / g. Therefore, the electrochemical performance of lithium battery graphite negative electrode materials such as the initial discharge specific capacity still needs to be further improved.

[0005] Therefore, there is an urgent need for a preparation method and application of a graphite negative electrode material for new energy batteries. Summary of the Invention

[0006] The purpose of the present invention is to provide a preparation method and application of a graphite negative electrode material for new energy batteries.

[0007] To achieve the above purpose, the present invention provides the following technical solutions:

[0008] A preparation method of a graphite negative electrode material for new energy batteries, the preparation method comprising the following steps:

[0009] (1) Mix natural graphite and water at a weight ratio of 1:(4 - 6), add them to a plasma reactor for spark plasma discharge to obtain pretreated graphite powder;

[0010] (2) Mix polyethylene glycol, calcium chloride and water at a weight ratio of (3 - 6):1:(10 - 13), stir evenly to obtain a mixed solution A; add the pretreated graphite powder to the mixed solution A, continue to add a surfactant, and stir for 4 - 6 h to obtain a mixed solution B;

[0011] (3) Heat the mixture B to 80 - 85 °C for evaporation until it becomes a gel-like substance, and vacuum dry the gel-like substance to obtain a precursor.

[0012] (4) Calcinate the precursor in a nitrogen atmosphere. After calcination is completed, crush it and sieve it to obtain a graphite anode material for new energy batteries.

[0013] Further, in the step (1), the spark plasma discharge has a voltage of 10 - 15 KV, a current of 80 - 100 A, a pulse of 500 - 600 ns, a cumulative reaction time of 1 - 2 hours, and the reaction conditions are a temperature of 80 - 100 °C.

[0014] In the prior art, polymers are directly used to carbon-coat natural graphite. Due to poor dispersion uniformity after mixing and uneven coating, the initial discharge capacity of lithium-ion batteries is not ideal. In the present invention, the natural graphite is pretreated, which can improve the initial discharge capacity of lithium-ion batteries. Through plasma discharge treatment, the specific surface area of natural graphite can be increased, and at the same time, the surface of graphite powder is rich in groups such as carboxyl, hydroxyl, and epoxy groups, which can not only increase the specific surface area of graphite but also improve its dispersibility. Under these conditions, the initial charge-discharge efficiency of the battery is improved simultaneously.

[0015] Further, in the step (2), the polyethylene glycol is polyethylene glycol 400, polyethylene glycol 800, and polyethylene glycol 2000 with a weight ratio of 1:(1.2 - 1.5):(0.6 - 0.8).

[0016] In the present invention, by preparing a precursor from polyethylene glycol with a specific ratio and pretreated graphite, the cycle capacity retention rate of lithium-ion batteries at room temperature can be improved. The analysis is that PEGs with different molecular weights behave differently in the mixture: polyethylene glycol 400 (PEG400): PEG with a lower molecular weight is more easily soluble and has good fluidity, which helps to promote the uniform mixing between other components; polyethylene glycol 800 (PEG800) and polyethylene glycol 2000 (PEG2000): PEG with a higher molecular weight has better film-forming properties and can provide structural support, which helps to form a stable gel network. When these PEGs with different molecular weights are mixed in a certain proportion, they can work together to provide good dispersibility and film-forming properties, thereby improving the cycle capacity retention rate of lithium-ion batteries at room temperature. However, the capacity retention rates of the battery at high and low temperatures are not ideal.

[0017] Further, in the step (2), the weight of the surfactant accounts for 1 - 2% of the weight of the pretreated graphite powder.

[0018] Further, in the step (2), the surfactant comprises alkyl polyglycoside (model: APG1214, purchased from Jinan Mingjiang Chemical Co., Ltd.), polyoxyethylene fatty alcohol ether (AEO-9) and polyoxyethylene ether non-ionic surfactant, which are mixed in a weight ratio of (1.2-1.4):(0.3-0.6):1.

[0019] Further, the preparation method of the polyoxyethylene ether non-ionic surfactant in the step (2) comprises the following steps:

[0020] (1) Under a nitrogen atmosphere, 60-70 parts by weight of mixed unit alcohols and 2-5 parts by weight of KOH are mixed, heated to 110-130 °C, and then 30-40 parts by weight of ethylene oxide are added dropwise at a uniform rate for 1-2 h. After the addition is completed, the reaction is carried out under a pressure of 0.2-0.4 MPa and a temperature of 120-130 °C for 1-2 h to obtain an oligomer polyether polyol.

[0021] (2) Under a nitrogen atmosphere, 70-80 parts by weight of the oligomer polyether polyol, 20-30 parts by weight of mixed polyols and 2-4 parts by weight of catalase (purchased from Shanghai Macklin Biochemical Co., Ltd., product number C6319) catalyst are added to the reaction kettle, heated to 140-145 °C, pressurized to 0.3-0.4 MPa. When the pressure starts to drop, the temperature is controlled at 110-115 °C and the pressure is 0.3-0.4 MPa, and the reaction is carried out for 2-3 h to obtain the polyoxyethylene ether non-ionic surfactant.

[0022] Further, the mixed unit alcohols are a mixture of octanol, lauryl alcohol and isomeric tridecanol in a weight ratio of 1:(1.3-1.5):(0.6-0.8).

[0023] Further, the mixed polyols are a mixture of glycerol, pentaerythritol and sorbitol in a weight ratio of (1.6-1.8):1:(0.3-0.5).

[0024] The present invention attempts to use commercially available surfactants to improve the uniformity of the mixed liquid B, but the effect is not ideal. By mixing alkyl polyglycoside, polyoxyethylene fatty alcohol ether and polyoxyethylene ether non-ionic surfactant, the present invention can improve the capacity retention rate of the battery at low temperature. And when the alkyl polyglycoside, polyoxyethylene fatty alcohol ether and polyoxyethylene ether non-ionic surfactant are in specific ratio conditions, the capacity retention rate at high temperature is also improved. The surfactant under these conditions can better disperse the polymer and the pretreated graphite, ensuring a more uniform distribution and coating of the polymer and graphite particles, thereby enhancing the contact between the graphite and the electrolyte and forming a more stable solid electrolyte interface (SEI) film.

[0025] Further, in the step (3), vacuum drying is carried out at 60-65 °C for 25-30 h.

[0026] Further, the screen mesh number in the step (4) is 325 meshes.

[0027] Further, the calcination conditions in the step (4) are: calcination at a temperature of 1100 - 1200 °C for 2 - 3 h.

[0028] The present invention also provides an application of a preparation method of a graphite negative electrode material for a new energy battery.

[0029] Compared with the prior art, the advantages and beneficial effects of the present invention are:

[0030] 1. The graphite negative electrode material prepared by the present invention can improve the initial discharge specific capacity of the lithium battery, has high rate performance, and good high-temperature resistance effect.

[0031] 2. The present invention pre-treats natural graphite, which can improve the initial discharge capacity of the lithium-ion battery. At the same time, the initial charge-discharge efficiency of the battery is improved.

[0032] 3. The precursor prepared by the present invention from polyethylene glycol with a specific ratio and pre-treated graphite can improve the cycle capacity retention rate of the lithium-ion battery at room temperature.

[0033] 4. The present invention can improve the capacity retention rate of the battery at low temperature by mixing alkyl polyglycoside, polyoxyethylene fatty alcohol ether and polyoxyethylene ether non-ionic surfactants. And when the alkyl polyglycoside, polyoxyethylene fatty alcohol ether and polyoxyethylene ether non-ionic surfactants are under specific ratio conditions, the capacity retention rate at high temperature is also improved. Specific Embodiments

[0034] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts belong to the scope of protection of the present invention.

[0035] The average particle size of the natural graphite used in the following examples is 20 μm and the particle size is between 10 - 30 μm.

[0036] Example 1

[0037] This example provides a preparation method of a graphite negative electrode material for a new energy battery, and the preparation method includes the following steps:

[0038] (1) Mix natural graphite and water at a weight ratio of 1:5, add them to a plasma reactor for spark plasma discharge. The spark plasma discharge has a voltage of 12 KV, a current of 90 A, a pulse of 550 ns, a cumulative reaction time of 1.4 hours, and a reaction temperature of 90 °C; pretreated graphite powder is obtained. The plasma reactor is a container with flat electrodes on both sides, a wire mesh at the bottom, and insulated and sealed on all sides, with a capacity of 20 L, a distance of 20 cm between the flat electrodes, and the holes of the wire mesh are 1 mm.

[0039] (2) Mix polyethylene glycol, calcium chloride and water at a weight ratio of 5:1:12, stir evenly to obtain mixture A; add the pretreated graphite powder to mixture A, then continue to add a surfactant and stir for 5 h to obtain mixture B; the polyethylene glycol is polyethylene glycol 400, polyethylene glycol 800 and polyethylene glycol 2000 at a weight ratio of 1:1.4:0.7; the weight of the surfactant accounts for 1.5% of the weight of the pretreated graphite powder; the surfactant includes a mixture of alkyl polyglycoside (model: APG1214, purchased from Jinan Mingjiang Chemical Co., Ltd.), polyoxyethylene fatty alcohol ether (AEO-9) and polyoxyethylene ether non-ionic surfactant at a weight ratio of 1.3:0.5:1.

[0040] The preparation method of the polyoxyethylene ether non-ionic surfactant includes the following steps:

[0041] S1: Under a nitrogen atmosphere, mix 65 parts by weight of mixed unit alcohols and 4 parts by weight of KOH, heat up to 120 °C, then dropwise add 35 parts by weight of ethylene oxide, dropwise add it evenly for 1.3 h. After the dropping is completed, keep the temperature at 125 °C and the pressure at 0.3 MPa for 1.6 h to obtain the oligomer polyether polyol; the mixed unit alcohols are a mixture of octanol, lauryl alcohol and isomeric tridecanol at a weight ratio of 1:1.4:0.7.

[0042] S2: Under a nitrogen atmosphere, add 75 parts by weight of the oligomer polyether polyol, 25 parts by weight of the mixed polyols and 3 parts by weight of the catalase (purchased from Shanghai Macklin Biochemical Co., Ltd., product number C6319) catalyst to the reaction kettle. The mixed polyols are a mixture of glycerol, pentaerythritol and sorbitol at a weight ratio of 1.7:1:0.4; heat up to 142 °C, pressurize to 0.35 MPa. When the pressure starts to drop, control the temperature at 112 °C and the pressure at 0.35 MPa, and react for 2.6 h to obtain the polyoxyethylene ether non-ionic surfactant.

[0043] (3) Heat mixture B to 82 °C for evaporation until it becomes a gel-like substance, and vacuum dry the gel-like substance at 62 °C for 27 h to obtain the precursor.

[0044] (4) Calcinate the precursor in a nitrogen atmosphere under the following calcination conditions: the temperature is 1150 °C and the calcination time is 2.6 h. After the calcination is completed, pulverize it and pass through a 325-mesh sieve to obtain the graphite negative electrode material for new energy batteries.

[0045] Example 2

[0046] This example provides a preparation method of a graphite negative electrode material for new energy batteries, and the preparation method includes the following steps:

[0047] (1) Mix natural graphite and water with a weight ratio of 1:4, add them to a plasma reactor for spark plasma discharge. The spark plasma discharge is at a voltage of 10 KV, a current of 80 A, a pulse of 500 ns, and the cumulative reaction time is 1 hour. The reaction condition is a temperature of 80 °C to obtain pretreated graphite powder. The plasma reactor is a container with flat electrodes on both sides, a wire mesh at the bottom, and insulated and sealed on all sides. The capacity is 20 L, the distance between the flat electrodes is 20 cm, and the holes of the wire mesh are 1 mm.

[0048] (2) Mix polyethylene glycol, calcium chloride and water with a weight ratio of 3:1:10, stir evenly to obtain mixture A; add the pretreated graphite powder to mixture A, continue to add a surfactant, and stir for 4 h to obtain mixture B. The polyethylene glycol is polyethylene glycol 400, polyethylene glycol 800 and polyethylene glycol 2000 with a weight ratio of 1:1.2:0.6; the weight of the surfactant accounts for 1% of the weight of the pretreated graphite powder. The surfactant includes a mixture of alkyl polyglycoside (model: APG1214, purchased from Jinan Mingjiang Chemical Co., Ltd.), polyoxyethylene fatty alcohol ether (AEO-9) and polyoxyethylene ether non-ionic surfactant with a weight ratio of 1.2:0.3:1;

[0049] The preparation method of the polyoxyethylene ether non-ionic surfactant includes the following steps:

[0050] S1: In a nitrogen atmosphere, mix 60 parts by weight of mixed unit alcohols and 2 parts by weight of KOH, heat up to 110 °C, then dropwise add 40 parts by weight of ethylene oxide at a uniform speed for 1 h. After the dropping is completed, keep the temperature at 120 °C under a pressure of 0.2 MPa and react for 1 h to obtain the oligomer polyether polyol. The mixed unit alcohols are a mixture of octanol, lauryl alcohol and isomeric tridecanol with a weight ratio of 1:1.3:0.6;

[0051] S2: Under a nitrogen atmosphere, 70 parts by weight of oligomeric polyether polyol, 30 parts by weight of mixed polyols, and 2 parts by weight of catalase (purchased from Shanghai Macklin Biochemical Co., Ltd., product number C6319) catalyst are added to a reaction kettle. The mixed polyols are a mixture of glycerol, pentaerythritol, and sorbitol in a weight ratio of 1.6:1:0.3. The temperature is raised to 140 °C and the pressure is increased to 0.3 MPa. When the pressure starts to drop, the temperature is controlled at 110 °C and the pressure at 0.3 MPa, and the reaction is carried out for 2 h to obtain a polyoxyethylene ether non-ionic surfactant.

[0052] (3) Heat the mixed liquid B to 80 °C for evaporation until it becomes a gel-like substance, and vacuum dry the gel-like substance at 60 °C for 25 h to obtain a precursor.

[0053] (4) Calcinate the precursor under a nitrogen atmosphere. The calcination conditions are: calcination at 1100 °C for 2 h. After calcination is completed, it is pulverized and screened through a 325-mesh sieve to obtain a graphite negative electrode material for new energy batteries.

[0054] Example 3

[0055] This example provides a preparation method of a graphite negative electrode material for new energy batteries. The preparation method includes the following steps:

[0056] (1) Mix natural graphite and water in a weight ratio of 1:6, add them to a plasma reactor for spark plasma discharge. The spark plasma discharge is at a voltage of 15 KV, a current of 100 A, a pulse of 600 ns, and the cumulative reaction time is 2 hours. The reaction condition is a temperature of 100 °C to obtain pretreated graphite powder. The plasma reactor is a container with flat electrodes on both sides, a wire mesh at the bottom, and insulated and sealed all around. The capacity is 20 L, the distance between the flat electrodes is 20 cm, and the holes of the wire mesh are 1 mm.

[0057] (2) Mix polyethylene glycol, calcium chloride, and water in a weight ratio of 6:1:13, stir evenly to obtain a mixed liquid A. Add the pretreated graphite powder to the mixed liquid A, then continue to add a surfactant and stir for 6 h to obtain a mixed liquid B. The polyethylene glycol is a mixture of polyethylene glycol 400, polyethylene glycol 800, and polyethylene glycol 2000 in a weight ratio of 1:1.5:0.8. The weight of the surfactant accounts for 2% of the weight of the pretreated graphite powder. The surfactant includes a mixture of alkyl polyglycoside (model: APG1214, purchased from Jinan Mingjiang Chemical Co., Ltd.), polyoxyethylene fatty alcohol ether (AEO-9), and polyoxyethylene ether non-ionic surfactant in a weight ratio of 1.4:0.6:1.

[0058] The preparation method of the polyoxyethylene ether non-ionic surfactant includes the following steps:

[0059] S1: Under a nitrogen atmosphere, 70 parts by weight of mixed unit alcohols and 5 parts by weight of KOH are mixed, heated to 130 °C, and then 30 parts by weight of ethylene oxide are added dropwise at a uniform rate for 2 h. After the addition is completed, the mixture is kept at a pressure of 0.4 MPa and a temperature of 130 °C for 2 h to obtain an oligomeric polyether polyol; the mixed unit alcohols are a mixture of octanol, lauryl alcohol, and isomeric tridecanol with a weight ratio of 1:1.5:0.8.

[0060] S2: Under a nitrogen atmosphere, 80 parts by weight of the oligomeric polyether polyol, 20 parts by weight of mixed polyols, and 4 parts by weight of catalase (purchased from Shanghai Macklin Biochemical Co., Ltd., product number C6319) catalyst are added to the reaction kettle. The mixed polyols are a mixture of glycerol, pentaerythritol, and sorbitol with a weight ratio of 1.8:1:0.5; the temperature is raised to 145 °C, the pressure is increased to 0.4 MPa, and when the pressure starts to drop, the temperature is controlled at 115 °C and the pressure at 0.4 MPa for 3 h to obtain a polyoxyethylene ether non-ionic surfactant.

[0061] (3) Heat the mixed liquid B to 85 °C for evaporation until it becomes a gel-like substance, and vacuum dry the gel-like substance at 65 °C for 30 h to obtain a precursor.

[0062] (4) Calcinate the precursor under a nitrogen atmosphere. The calcination conditions are: calcination at 1200 °C for 3 h. After the calcination is completed, pulverize it and pass through a 325-mesh sieve to obtain a graphite negative electrode material for new energy batteries.

[0063] Comparative Example 1

[0064] The difference between this comparative example and Example 1 is: the preparation method of the pretreated graphite powder is different.

[0065] Specifically: Place natural graphite in a muffle furnace and calcine it at 800 °C for 1.5 h to obtain pretreated graphite powder.

[0066] Comparative Example 2

[0067] The difference between this comparative example and Example 1 is: the spark plasma discharge has a voltage of 8 kV, a current of 120 A, a pulse of 400 ns, a cumulative reaction time of 2.4 h, and the reaction conditions are a temperature of 70 °C.

[0068] Comparative Example 3

[0069] The difference between this comparative example and Example 1 is: the polyethylene glycol is polyethylene glycol 400, polyethylene glycol 800, and polyethylene glycol 2000 with a weight ratio of 1:1:1.

[0070] Comparative Example 4

[0071] The difference between this comparative example and Example 1 is that the surfactant comprises a mixture of alkyl polyglycoside, polyoxyethylene fatty alcohol ether and polyoxyethylene ether nonionic surfactant in a weight ratio of 1:1:1.

[0072] Comparative Example 5

[0073] The difference between this comparative example and Example 1 is that the surfactant comprises a mixture of alkyl polyglycoside (model: APG1214, purchased from Jinan Mingjiang Chemical Co., Ltd.), polyoxyethylene fatty alcohol ether (AEO-9) and Tween 60 in a weight ratio of 1.3:0.5:1.

[0074] Comparative Example 6

[0075] The difference between this comparative example and Example 1 is that the mixed unit alcohol is a mixture of octanol, lauryl alcohol and isomeric tridecanol in a weight ratio of 1:1:1; the mixed polyol is a mixture of glycerol, pentaerythritol and sorbitol in a weight ratio of 1:1:1.

[0076] Performance Test

[0077] Half-cell test method: The negative electrode materials prepared in Examples 1-3 and Comparative Examples 1-6: conductive carbon black (SP): carboxymethyl cellulose (CMC): styrene-butadiene rubber (SBR) = 95:1:1.5:2.5 were mixed evenly, coated on a copper foil, and the coated electrode was placed in a vacuum drying oven at 120 °C for 12 hours. The simulated battery assembly was carried out in a Braun glove box under argon protection. The electrolyte was 1M-LiPF6 + EC:DEC:DMC = 1:1:1 (volume ratio), and the metal lithium sheet was used as the counter electrode. The simulated battery test was carried out on a Neware battery test cabinet at 5V-10mA. The charge-discharge voltage was 0.01-1.5V, and the charge-discharge rate was 0.1C. The first capacity and efficiency obtained from the test are listed in Table 1.

[0078] Full-cell test method: Using the negative electrode materials prepared in Examples 1-3 and Comparative Examples 1-6 as the negative electrode, lithium cobaltate as the positive electrode, and 1M-LiPF6 + EC:DEC:DMC = 1:1:1 (volume ratio) solution as the electrolyte to assemble a full cell, and performing charge and discharge at a rate of 1C at room temperature, 45 °C and -10 °C. The voltage range was 3.0-4.2V. The cycle performance obtained from the test is listed in Table 1.

[0079] The specific test results are shown in Table 1.

[0080] Table 1 Electrochemical Performance Test Results

[0081]

[0082]

[0083] As can be seen from the above performance test results, the lithium batteries prepared with the negative electrode materials of Examples 1-3 have excellent performance, and in particular, the comprehensive performance of Example 1 is the most prominent.

[0084] However, in the comparative examples, since the necessary technical solutions were not adopted, their performance in the corresponding performance tests was significantly worse than that of the examples. In Comparative Example 1, the change in the pretreatment method of natural graphite led to a decrease in the first discharge capacity of the lithium-ion battery; in Comparative Example 2, the change in the spark plasma discharge conditions affected the group distribution on the surface of the pretreated graphite, further affecting the first discharge capacity of the lithium-ion battery; in Comparative Example 3, the ratio of polyethylene glycol was changed, resulting in a decrease in the cycle capacity retention rate of the lithium-ion battery at room temperature; in Comparative Examples 4-6, the surfactant composition was changed, resulting in a decrease in the effect of improving the capacity retention rate of the battery at high and low temperatures. The above experimental results further prove the importance of the technical solutions defined in the present invention for their technical effects.

[0085] The above is the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle described in the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing a graphite negative electrode material for a new energy battery, characterized in that: The preparation method comprises: (1) Natural graphite and water in a weight ratio of 1:(4-6) are mixed and added into a plasma reactor for spark plasma discharge to obtain pretreated graphite powder; the voltage of the spark plasma discharge is 10-15KV, the current is 80-100A, the pulse is 500-600ns, the cumulative reaction time is 1-2 hours, and the reaction temperature is 80-100°C; (2) Mix polyethylene glycol, calcium chloride and water in a weight ratio of (3-6):1:(10-13), stir evenly to obtain a mixed solution A; add the pretreated graphite powder to the mixed solution A, add a surfactant, stir for 4-6 hours, and obtain a mixed solution B; Among them, polyethylene glycol is in a weight ratio of 1: (1.2-1.5): (0.6-0.8) polyethylene glycol 400, polyethylene glycol 800 and polyethylene glycol 2000; the surfactant is in a weight ratio of (1.2-1.4): (0.3-0.6): 1 alkyl glycoside, polyoxyethylene fatty alcohol ether and polyoxyethylene ether nonionic surfactant; The preparation method of the polyoxyethylene ether nonionic surfactant comprises: (A) Under a nitrogen atmosphere, 60-70 parts by weight of a mixed monoalcohol and 2-5 parts by weight of KOH are mixed, the temperature is raised to 110-130° C., 30-40 parts by weight of ethylene oxide are added dropwise at a uniform rate for 1-2 hours, and after the addition is completed, the mixture is kept at 0.2-0.4 MPa and 120-130° C. for 1-2 hours to obtain an oligomer polyether polyol; the mixed monoalcohol is octanol, lauryl alcohol and isomeric tridecanol in a weight ratio of 1: (1.3-1.5): (0.6-0.8); (B) under nitrogen atmosphere, 70-80 parts by weight of oligomer polyether polyol, 20-30 parts by weight of mixed polyol and 2-4 parts by weight of catalase catalyst are added into a reaction kettle, the temperature is raised to 140-145° C., the pressure is increased to 0.3-0.4 MPa, and when the pressure drops, the temperature is controlled to 110-115° C., the pressure is 0.3-0.4 MPa, and the reaction is carried out for 2-3 hours to obtain a polyoxyethylene ether nonionic surfactant; the mixed polyol is glycerol, pentaerythritol and sorbitol in a weight ratio of (1.6-1.8):1:(0.3-0.5); (3) heating the mixed solution B to 80-85°C for evaporation until it becomes a gel-like substance, and then vacuum drying to obtain a precursor; (4) The precursor is calcined in a nitrogen atmosphere, and then crushed and sieved to obtain a graphite negative electrode material for new energy batteries.

2. The method for preparing a graphite negative electrode material for a new energy battery according to claim 1, characterized in that: The weight of the surfactant in step (2) is 1-2% of the weight of the pretreated graphite powder.

3. The method for preparing a graphite negative electrode material for a new energy battery according to claim 1, characterized in that: The calcination conditions in step (4) are: calcination at a temperature of 1100-1200° C. for 2-3 hours.

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