Aqueous homogenization process, slurry and lithium battery for lithium-ion battery positive electrode system

Abstract

The present invention provides an aqueous homogenization process for a lithium-ion battery positive electrode system, a slurry, and a lithium battery. The aqueous homogenization process comprises the following steps: (1) mixing a positive electrode main material and a conductive agent to obtain a mixed powder, and soaking the mixed powder with water to obtain a wet first slurry; (2) mixing an aqueous adhesive glue, an aqueous conductive agent glue, and the first slurry obtained in step (1), and simultaneously performing vacuum stirring and vacuum dispersion to obtain a muddy second slurry; (3) mixing the aqueous adhesive glue, water, and the second slurry obtained in step (2), and simultaneously performing vacuum stirring and vacuum dispersion to obtain a lithium-ion battery positive electrode slurry. The lithium-ion battery positive electrode slurry prepared by the aqueous homogenization process for the lithium-ion battery positive electrode system of the present invention has a low particle size and high stability. The aqueous homogenization process is short in time, has high preparation efficiency, low preparation cost, and low requirements for the production environment and production equipment.

Description

Technical Field

[0001] The present invention belongs to the field of battery technology and relates to an aqueous homogenization process for a lithium-ion battery positive electrode system, in particular to an aqueous homogenization process for a lithium-ion battery positive electrode system, a slurry and a lithium battery. Background Art

[0002] Lithium-ion batteries, with their long cycle life, high energy density, and environmentally friendly advantages, are widely used in electric vehicles and energy storage. The production process for lithium-ion batteries includes homogenization, coating, roller pressing, assembly, and formation. Homogenization is the first and most important step. The quality of the slurry plays a decisive role in the subsequent coating and the performance of the final lithium-ion battery.

[0003] Currently, the industry's prevalent oil-based process for stirring lithium-ion battery cathodes uses N-methylpyrrolidone as the solvent. This solvent has a pungent odor, is harmful to the human body through long-term exposure, is costly, and is highly hygroscopic. Consequently, oil-based processes place high demands on the battery manufacturing environment and are costly. Consequently, aqueous processes using deionized water as the solvent have become a research focus within the industry. Deionized water offers low cost, is non-toxic, and has lower environmental requirements for production. However, the solubility of water for active substances and conductive agents is much lower than that of N-methylpyrrolidone, making them difficult to disperse directly in deionized water.

[0004] Currently, there are three main types of homogenization processes for positive electrode slurries: (1) dry homogenization process, in which the dry powders of active material, conductive agent and binder are first mixed evenly, then an appropriate amount of solvent is added for kneading, and finally the solvent is added for high-speed dispersion to obtain slurry; (2) semi-dry homogenization process, in which the dry powders of active material and conductive agent are generally mixed evenly first, and then the glue prepared in advance is added to the above dry powder for kneading, and finally the solvent is added for high-speed dispersion to obtain slurry; (3) wet homogenization process, in which the glue is generally prepared first, and then the conductive agent is added to the glue for dispersion, and then the active material is added for dispersion, and finally the slurry is obtained after high-speed dispersion.

[0005] When these three homogenization processes are applied to the aqueous system, it is found that: (1) In the dry homogenization process, the dry powder is easy to agglomerate during the first step of adding glue, which is not conducive to the dispersion of the subsequent process. The dispersion process requires a large shear force, which has high requirements on equipment and leads to increased production costs. (2) In the semi-dry homogenization process, kneading will cause the stirring paddle to scratch the cylinder wall, and the slurry will stick to the cylinder wall. The slurry cannot be squeezed and rubbed in time, and thus the particle size cannot be reduced. (3) In the wet homogenization process, the conductive agent has a large specific surface area and is easy to agglomerate in water. Most of the conductive agents are hydrophobic particles, which are more difficult to disperse than in oil-based binders. In addition, the solid content of the conductive agent in the conductive glue is relatively low, and the conductive agent cannot be dispersed by friction and extrusion. Therefore, the particle size of the conductive glue cannot be reduced, resulting in a large particle size of the slurry. In addition, the wet homogenization process is generally time-consuming. The above homogenization processes can prepare a non-settling and stable slurry in an oil-based solvent system. However, when these three homogenization processes are applied to a water-based system, it is difficult to prepare a slurry with small fineness and high stability.

[0006] CN114628636A discloses a method for homogenizing a positive electrode for a lithium-ion battery, comprising the following steps: first, mixing water and a binder, and stirring; then, sequentially, adding a conductive agent and stirring, adding the positive electrode active material and stirring, and then adding an additive and stirring; and finally, adding water to adjust the viscosity; the additive contains a lipophilic group. This invention adds an additive containing a lipophilic group to the positive electrode slurry, suppressing the pseudoplasticity of the binder, resulting in a stable slurry viscosity and state, making it easier to apply. However, the slurry produced by this method for homogenizing a positive electrode for a lithium-ion battery has a high fineness and low stability.

[0007] CN109921098A discloses a method for preparing an aqueous super-nano lithium iron phosphate battery. The lithium iron phosphate battery in this invention first prepares positive and negative electrode slurries, applies the resulting positive and negative electrode slurries to aluminum foil surfaces to form positive and negative electrode sheets, stacks the positive and negative electrode sheets, places them in a battery housing, and injects electrolyte, ultimately completing the formation and capacity separation steps to obtain the lithium iron phosphate battery. However, this aqueous super-nano lithium iron phosphate battery preparation method involves mixing and homogenizing lithium iron phosphate powder particles with a conductive agent and an aqueous binder to obtain a positive electrode slurry. The resulting positive electrode slurry has large particle size and poor uniformity.

[0008] CN113540399A discloses a water-based negative electrode sheet for a high-power lithium-ion battery and a preparation method thereof. This invention specifically discloses a material formula and formula ratio of a water-based negative electrode sheet for high-power lithium-ion power batteries, using pure water / deionized water as a solvent and a low-cost aqueous binder to prepare the negative electrode sheet; discloses a more efficient, more environmentally friendly, time- and cost-saving slurry preparation process to solve problems such as agglomeration and sedimentation during the slurrying process; in addition, it discloses a coating parameter and rolling density of a high-power battery negative electrode sheet, thereby ensuring the consistency and low internal resistance of the high-power electrode sheet, eliminating the risk of peeling and shedding of the electrode sheet, and achieving the high power characteristics and consistency of the battery. However, the preparation process of the preparation method of the water-based negative electrode sheet for high-power lithium-ion batteries is complicated and the preparation efficiency is low.

[0009] Currently available aqueous homogenization processes for lithium-ion battery cathode systems have certain drawbacks, including high particle size and low stability of the prepared cathode slurry, complex preparation methods, low efficiency, high production costs, and strict requirements on the production environment. Therefore, the development and design of a novel aqueous homogenization process for lithium-ion battery cathode systems, slurry, and lithium battery are crucial. Summary of the Invention

[0010] In view of the shortcomings of the prior art, the object of the present invention is to provide an aqueous homogenization process, slurry and lithium battery for a lithium ion battery positive electrode system. The lithium ion battery positive electrode slurry prepared by the aqueous homogenization process for the lithium ion battery positive electrode system of the present invention has low particle size and high stability. The aqueous homogenization process is short in time, has high preparation efficiency, low preparation cost and low requirements for the production environment and production equipment.

[0011] To achieve this object, the present invention adopts the following technical solutions:

[0012] In a first aspect, the present invention provides an aqueous homogenization process for a lithium-ion battery positive electrode system, the aqueous homogenization process comprising the following steps:

[0013] (1) mixing a positive electrode main material and a conductive agent to obtain a mixed powder, and soaking the mixed powder with water to obtain a wet first slurry;

[0014] (2) mixing the aqueous adhesive solution, the aqueous conductive agent solution and the first slurry obtained in step (1), and then simultaneously performing vacuum stirring and vacuum dispersion to obtain a wet second slurry;

[0015] (3) After mixing the aqueous adhesive solution, water and the second slurry obtained in step (2), vacuum stirring and vacuum dispersion are simultaneously performed to obtain a lithium-ion battery positive electrode slurry.

[0016] In the aqueous slurrying process of the lithium ion battery positive electrode system of the present invention, in step (1), the positive electrode main material and the conductive agent are mixed, and then a small amount of water is added to moisten them first, thereby avoiding the agglomeration of the mixed powder; in step (2), the aqueous adhesive glue, the aqueous conductive agent glue and the first slurry are scraped when mixed, and stirred and dispersed at a suitable solid content. The solid content will not make the slurry reach a kneading state, thereby avoiding the kneading process causing the stirring paddle to scratch the cylinder wall and stick to the cylinder, thereby avoiding the slurry sticking to the cylinder not being able to be squeezed and rubbed in time, resulting in poor dispersion effect of the final lithium ion battery positive electrode slurry; in step (2), the aqueous adhesive glue, the aqueous conductive agent glue and the first slurry are evenly dispersed through a one-step glue adding process, which effectively reduces the investment cost of the slurry preparation process, shortens the time of the aqueous slurrying process, improves the overall process efficiency, and effectively ensures the stability and uniformity of the aqueous positive electrode system slurry.

[0017] The lithium ion battery positive electrode slurry prepared by the aqueous homogenization process of the lithium ion battery positive electrode system of the present invention has low particle size and high stability. The aqueous homogenization process is short in time, high in preparation efficiency, low in preparation cost and has low requirements on the production environment and production equipment.

[0018] Preferably, the mixing method in step (1) includes a first stirring.

[0019] Preferably, the first stirring speed is 15-30 rpm and the time is 10-30 min.

[0020] The present invention limits the first stirring speed to 15 to 30 rpm, for example, it can be 15 rpm, 16 rpm, 17 rpm, 18 rpm, 19 rpm, 20 rpm, 21 rpm, 22 rpm, 23 rpm, 24 rpm, 25 rpm, 26 rpm, 27 rpm, 28 rpm, 29 rpm or 30 rpm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0021] The present invention limits the first stirring time to 10-30 min, for example, it can be 10 min, 12 min, 14 min, 16 min, 18 min, 20 min, 22 min, 24 min, 26 min, 28 min or 30 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0022] Preferably, the soaking method in step (1) includes a second stirring.

[0023] Preferably, the second stirring speed is 15-30 rpm and the time is 10-30 min.

[0024] The present invention limits the second stirring speed to 15 to 30 rpm, for example, it can be 15 rpm, 16 rpm, 17 rpm, 18 rpm, 19 rpm, 20 rpm, 21 rpm, 22 rpm, 23 rpm, 24 rpm, 25 rpm, 26 rpm, 27 rpm, 28 rpm, 29 rpm or 30 rpm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0025] The present invention limits the second stirring time to 10-30 min, for example, it can be 10 min, 12 min, 14 min, 16 min, 18 min, 20 min, 22 min, 24 min, 26 min, 28 min or 30 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0026] Preferably, the positive electrode main material in step (1) includes any one or a combination of at least two of a ternary positive electrode material, lithium iron phosphate, elemental sulfur or lithium manganate. Typical but non-limiting combinations include a combination of a ternary positive electrode material and lithium iron phosphate, a combination of lithium iron phosphate and elemental sulfur, a combination of elemental sulfur and lithium manganate, or a combination of a ternary positive electrode material, lithium iron phosphate and elemental sulfur.

[0027] The ternary cathode material in the present invention includes lithium nickel cobalt manganese oxide and / or lithium nickel cobalt aluminum oxide.

[0028] Preferably, the conductive agent in step (1) comprises any one or a combination of at least two of conductive carbon black, conductive graphite, acetylene black or Ketjen black. Typical but non-limiting combinations include a combination of conductive carbon black and conductive graphite, a combination of conductive graphite and acetylene black, a combination of acetylene black and Ketjen black, or a combination of conductive carbon black, conductive graphite and Ketjen black.

[0029] Preferably, the solid content of the first slurry in step (1) is 80-85wt%, for example, it can be 80wt%, 80.5wt%, 81wt%, 81.5wt%, 82wt%, 82.5wt%, 83wt%, 83.5wt%, 84wt%, 84.5wt% or 85wt%, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0030] Preferably, the mass ratio of the positive electrode main material to the conductive agent in the first slurry in step (1) is (90-99): (0.5-10), for example, it can be 90:0.5, 90:1, 90:2, 90:3, 90:4, 90:5, 90:6, 90:7, 90:8, 90:9, 90:10, 99:0.5, 99:7 or 99:10, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0031] Preferably, the mixing method in step (2) includes a third stirring.

[0032] Preferably, the third stirring has a rotation speed of 15 to 30 rpm and a duration of 10 to 30 minutes.

[0033] The rotation speed of the third stirring in the present invention is 15 to 30 rpm, for example, it can be 15 rpm, 16 rpm, 17 rpm, 18 rpm, 19 rpm, 20 rpm, 21 rpm, 22 rpm, 23 rpm, 24 rpm, 25 rpm, 26 rpm, 27 rpm, 28 rpm, 29 rpm or 30 rpm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0034] The third stirring time in the present invention is 10 to 30 minutes, for example, it can be 10 minutes, 12 minutes, 14 minutes, 16 minutes, 18 minutes, 20 minutes, 22 minutes, 24 minutes, 26 minutes, 28 minutes or 30 minutes, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0035] Preferably, the rotation speed of the vacuum stirring in step (2) is 15 to 30 rpm, for example, it can be 15 rpm, 16 rpm, 17 rpm, 18 rpm, 19 rpm, 20 rpm, 21 rpm, 22 rpm, 23 rpm, 24 rpm, 25 rpm, 26 rpm, 27 rpm, 28 rpm, 29 rpm or 30 rpm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0036] Preferably, the rotation speed of the vacuum dispersion in step (2) is 500-800 rpm, for example, it can be 500 rpm, 550 rpm, 600 rpm, 650 rpm, 700 rpm, 750 rpm or 800 rpm, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0037] Preferably, the vacuum degree of the vacuum stirring and vacuum dispersion in step (2) is -0.1 to -0.085 MPa, for example, it can be -0.1 MPa, -0.098 MPa, -0.095 MPa, -0.092 MPa, -0.09 MPa, -0.088 MPa or -0.085 MPa, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0038] Preferably, the time for vacuum stirring and vacuum dispersion in step (2) is 3 to 5 hours, for example, it can be 3 hours, 3.2 hours, 3.5 hours, 4 hours, 4.2 hours, 4.5 hours, 4.7 hours or 5 hours, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0039] Preferably, the water-based adhesive solution in step (2) includes a water-based adhesive and water, and the water-based adhesive includes any one or a combination of at least two of polyvinylidene fluoride adhesive, styrene-butadiene rubber latex adhesive, carboxymethyl cellulose adhesive, polyacrylic acid adhesive, polyacrylonitrile adhesive or polyacrylate adhesive. Typical but non-limiting combinations include a combination of polyvinylidene fluoride adhesive and styrene-butadiene rubber latex adhesive, a combination of styrene-butadiene rubber latex adhesive and carboxymethyl cellulose adhesive, a combination of polyacrylic acid adhesive and polyacrylonitrile adhesive, a combination of polyacrylic acid adhesive and polyacrylonitrile adhesive and polyacrylate adhesive, or a combination of polyvinylidene fluoride adhesive, styrene-butadiene rubber latex adhesive and carboxymethyl cellulose adhesive.

[0040] Preferably, the solid content of the aqueous adhesive solution in step (2) is 15 to 20 wt%, for example, it can be 15 wt%, 15.5 wt%, 16 wt%, 16.5 wt%, 17 wt%, 17.5 wt%, 18 wt%, 18.5 wt%, 19 wt%, 19.5 wt% or 20 wt%, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0041] Preferably, the aqueous conductive agent glue in step (2) includes an aqueous conductive agent and water, and the aqueous conductive agent includes any one or a combination of at least two of carbon nanofibers, carbon nanotubes or graphene. Typical but non-limiting combinations include a combination of carbon nanofibers and carbon nanotubes, a combination of carbon nanotubes and graphene, a combination of carbon nanofibers and graphene, or a combination of carbon nanofibers, carbon nanotubes and graphene.

[0042] Preferably, the solid content of the aqueous conductive agent glue in step (2) is 5 to 10 wt%, for example, it can be 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt% or 10 wt%, but it is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0043] Preferably, the solid content of the second slurry in step (2) is 70-77wt%, for example, it can be 70wt%, 71wt%, 72wt%, 73wt%, 74wt%, 75wt%, 76wt% or 77wt%, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0044] Preferably, in step (2), the mass ratio of the positive electrode main material, the conductive agent, the aqueous adhesive and the aqueous conductive agent in the second slurry is (90-99):(0.5-10):(1-3):(0.5-10).

[0045] The mass ratio of the positive electrode main material to the conductive agent in the second slurry in step (2) of the present invention is (90-99): (0.5-10), for example, it can be 90:0.5, 90:1, 90:2, 90:3, 90:4, 90:5, 90:6, 90:7, 90:8, 90:9, 90:10, 99:0.5, 99:7 or 99:10, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0046] The mass ratio of the positive electrode main material to the aqueous adhesive in the second slurry in step (2) of the present invention is (90-99):(1-3), for example, it can be 90:1, 90:2, 90:3, 99:1, 99:2 or 99:3, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0047] The mass ratio of the positive electrode main material to the aqueous conductive agent in the second slurry in step (2) of the present invention is (90-99):(0.5-10), for example, it can be 90:0.5, 90:1, 90:2, 90:3, 90:4, 90:5, 90:6, 90:7, 90:8, 90:9, 90:10, 99:0.5, 99:7 or 99:10, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0048] Preferably, the mixing method in step (3) includes a fourth stirring.

[0049] Preferably, the fourth stirring has a rotation speed of 15 to 30 rpm and a time of 10 to 30 min.

[0050] The fourth stirring speed in the present invention is 15 to 30 rpm, for example, it can be 15 rpm, 16 rpm, 17 rpm, 18 rpm, 19 rpm, 20 rpm, 21 rpm, 22 rpm, 23 rpm, 24 rpm, 25 rpm, 26 rpm, 27 rpm, 28 rpm, 29 rpm or 30 rpm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0051] The fourth stirring time in the present invention is 10 to 30 minutes, for example, it can be 10 minutes, 12 minutes, 14 minutes, 16 minutes, 18 minutes, 20 minutes, 22 minutes, 24 minutes, 26 minutes, 28 minutes or 30 minutes, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0052] Preferably, the rotation speed of the vacuum stirring in step (3) is 15 to 30 rpm, for example, it can be 15 rpm, 16 rpm, 17 rpm, 18 rpm, 19 rpm, 20 rpm, 21 rpm, 22 rpm, 23 rpm, 24 rpm, 25 rpm, 26 rpm, 27 rpm, 28 rpm, 29 rpm or 30 rpm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0053] Preferably, the rotation speed of the vacuum dispersion in step (3) is 2500-3000 rpm, for example, it can be 2500 rpm, 2550 rpm, 2600 rpm, 2650 rpm, 2700 rpm, 2750 rpm, 2800 rpm, 2850 rpm, 2900 rpm, 2950 rpm or 3000 rpm, but is not limited to the listed values, and other values ​​not listed within this numerical range are also applicable.

[0054] Preferably, the vacuum degree of the vacuum stirring and vacuum dispersion in step (3) is -0.1 to -0.085 MPa, for example, it can be -0.1 MPa, -0.098 MPa, -0.095 MPa, -0.092 MPa, -0.09 MPa, -0.088 MPa or -0.085 MPa, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0055] Preferably, the time for vacuum stirring and vacuum dispersion in step (3) is 1 to 3 hours, for example, it can be 1 hour, 1.2 hours, 1.5 hours, 1.7 hours, 2 hours, 2.2 hours, 2.5 hours, 2.7 hours or 3 hours, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0056] Preferably, the water-based adhesive solution in step (3) is the same as the water-based adhesive solution in step (2).

[0057] Preferably, the solid content of the lithium-ion battery positive electrode slurry in step (3) is 55 to 60 wt%, for example, it can be 55 wt%, 56 wt%, 57 wt%, 58 wt%, 59 wt% or 60 wt%, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0058] Preferably, the viscosity of the lithium-ion battery positive electrode slurry in step (3) is 4000-8000cp, for example, it can be 4000cp, 4500cp, 5000cp, 5500cp, 6000cp, 6500cp, 7000cp, 7500cp or 8000cp, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0059] Preferably, the fineness of the lithium-ion battery positive electrode slurry in step (3) is 10 to 20 μm, for example, it can be 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm or 20 μm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0060] Preferably, the mass ratio of the positive electrode main material, the conductive agent, the aqueous adhesive and the aqueous conductive agent in the lithium ion battery positive electrode slurry in step (3) is (90-99):(0.5-10):(3-10):(0.5-10).

[0061] The mass ratio of the positive electrode main material to the conductive agent in the lithium ion battery positive electrode slurry in step (3) of the present invention is (90-99): (0.5-10), for example, it can be 90:0.5, 90:1, 90:2, 90:3, 90:4, 90:5, 90:6, 90:7, 90:8, 90:9, 90:10, 99:0.5, 99:7 or 99:10, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0062] The mass ratio of the positive electrode main material to the aqueous adhesive in the lithium ion battery positive electrode slurry in step (3) of the present invention is (90-99):(3-10), for example, it can be 90:3, 90:4, 90:5, 90:6, 90:7, 90:8, 90:9, 90:10, 99:3, 99:4, 99:5, 99:7 or 99:10, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0063] The mass ratio of the positive electrode main material to the aqueous conductive agent in the lithium ion battery positive electrode slurry in step (3) of the present invention is (90-99): (0.5-10), for example, it can be 90:0.5, 90:1, 90:2, 90:3, 90:4, 90:5, 90:6, 90:7, 90:8, 90:9, 90:10, 99:0.5, 99:7 or 99:10, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0064] As a preferred technical solution of the aqueous homogenization process described in the first aspect, the aqueous homogenization process comprises the following steps:

[0065] (1) mixing the positive electrode material and the conductive agent by a first stirring process at a speed of 15 to 30 rpm for 10 to 30 minutes to obtain a mixed powder, and then infiltrating the mixed powder with water by a second stirring process at a speed of 15 to 30 rpm for 10 to 30 minutes to obtain a first slurry with a wet solid content of 80 to 85 wt %, wherein the mass ratio of the positive electrode material to the conductive agent in the first slurry is (90 to 99):(0.5 to 10);

[0066] (2) After mixing the aqueous adhesive solution with a solid content of 15 to 20 wt %, the aqueous conductive agent solution with a solid content of 5 to 10 wt % and the first slurry obtained in step (1) by a third stirring process at a rotation speed of 15 to 30 rpm for 10 to 30 min, vacuum stirring at a rotation speed of 15 to 30 rpm and vacuum dispersion at a rotation speed of 500 to 800 rpm are simultaneously performed for 3 to 5 h under a vacuum degree of -0.1 to -0.085 MPa to obtain a muddy second slurry with a solid content of 70 to 77 wt %, wherein the mass ratio of the positive electrode main material, the conductive agent, the aqueous adhesive and the aqueous conductive agent in the second slurry is (90 to 99):(0.5 to 10):(1 to 3):(0.5 to 10);

[0067] (3) After the aqueous adhesive solution and water obtained in step (2) are mixed by a fourth stirring process at a rotation speed of 15 to 30 rpm for 10 to 30 min, vacuum stirring at a rotation speed of 15 to 30 rpm and vacuum dispersion at a rotation speed of 2500 to 3000 rpm are simultaneously performed for 1 to 3 h under a vacuum degree of -0.1 to -0.085 MPa to obtain a lithium ion battery positive electrode slurry with a solid content of 50 to 60 wt%, a viscosity of 4000-8000 cp and a fineness of 10 to 20 μm. The mass ratio of the positive electrode main material, the conductive agent, the aqueous adhesive and the aqueous conductive agent in the lithium ion battery positive electrode slurry is (90 to 99): (0.5 to 10): (3 to 10): (0.5 to 10).

[0068] In a second aspect, the present invention provides a positive electrode slurry for a lithium-ion battery, which is prepared by the aqueous homogenization process described in the first aspect.

[0069] In a third aspect, the present invention provides a lithium-ion battery, comprising the lithium-ion battery positive electrode slurry according to the second aspect.

[0070] Compared with the prior art, the present invention has the following beneficial effects:

[0071] The lithium ion battery positive electrode slurry prepared by the aqueous homogenization process of the lithium ion battery positive electrode system of the present invention has low particle size and high stability. The aqueous homogenization process is short in time, high in preparation efficiency, low in preparation cost and has low requirements on the production environment and production equipment. DETAILED DESCRIPTION

[0072] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0073] Example 1

[0074] This embodiment provides an aqueous homogenization process for a lithium-ion battery positive electrode system, the aqueous homogenization process comprising the following steps:

[0075] (1) mixing the positive electrode material and the conductive agent by a first stirring process at a speed of 24 rpm for 20 minutes to obtain a mixed powder, and then infiltrating the mixed powder with water by a second stirring process at a speed of 20 rpm for 15 minutes to obtain a muddy first slurry with a solid content of 82 wt%, wherein the mass ratio of the positive electrode material to the conductive agent in the first slurry is 95:2;

[0076] (2) After mixing the aqueous adhesive solution with a solid content of 17 wt %, the aqueous conductive agent solution with a solid content of 8 wt % and the first slurry obtained in step (1) by a third stirring process at a rotation speed of 20 rpm for 20 min, vacuum stirring at a rotation speed of 24 rpm and vacuum dispersion at a rotation speed of 580 rpm were simultaneously performed for 3 h at a vacuum degree of -0.096 MPa to obtain a muddy second slurry with a solid content of 73 wt %, wherein the mass ratio of the positive electrode main material, the conductive agent, the aqueous adhesive and the aqueous conductive agent in the second slurry was 95:2:1:2;

[0077] (3) After the fourth stirring mixing of the aqueous adhesive solution and water obtained in step (2) and the second slurry obtained in step (2) at a speed of 20 rpm and a time of 20 min, vacuum stirring at a speed of 28 rpm and vacuum dispersion at a speed of 2700 rpm were simultaneously performed for 2.5 hours at a vacuum degree of -0.092 MPa to obtain a lithium ion battery positive electrode slurry with a solid content of 55 wt%. The mass ratio of the positive electrode main material, the conductive agent, the aqueous adhesive and the aqueous conductive agent in the lithium ion battery positive electrode slurry is 95:2:3:2.

[0078] Example 2

[0079] This embodiment provides an aqueous homogenization process for a lithium-ion battery positive electrode system, the aqueous homogenization process comprising the following steps:

[0080] (1) mixing the positive electrode material and the conductive agent by a first stirring process at a speed of 20 rpm for 15 minutes to obtain a mixed powder, and then infiltrating the mixed powder with water by a second stirring process at a speed of 28 rpm for 13 minutes to obtain a muddy first slurry with a solid content of 81 wt%. The mass ratio of the positive electrode material to the conductive agent in the first slurry is 98:5;

[0081] (2) After mixing the aqueous adhesive solution with a solid content of 18 wt %, the aqueous conductive agent solution with a solid content of 9 wt % and the first slurry obtained in step (1) by a third stirring process at a speed of 24 rpm for 25 min, vacuum stirring at a speed of 20 rpm and vacuum dispersion at a speed of 720 rpm were simultaneously performed for 3.5 h at a vacuum degree of -0.088 MPa to obtain a muddy second slurry with a solid content of 75 wt %, wherein the mass ratio of the positive electrode main material, the conductive agent, the aqueous adhesive and the aqueous conductive agent in the second slurry was 98:5:2:3;

[0082] (3) After the fourth stirring mixing of the same aqueous adhesive solution as in step (2), water and the second slurry obtained in step (2) at a speed of 24 rpm and a time of 25 min, vacuum stirring at a speed of 24 rpm and vacuum dispersion at a speed of 2600 rpm were simultaneously performed for 2 h under a vacuum degree of -0.1 MPa to obtain a lithium ion battery positive electrode slurry with a solid content of 57 wt%. The mass ratio of the positive electrode main material, the conductive agent, the aqueous adhesive and the aqueous conductive agent in the lithium ion battery positive electrode slurry was 98:5:4:3.

[0083] Example 3

[0084] This embodiment provides an aqueous homogenization process for a lithium-ion battery positive electrode system, the aqueous homogenization process comprising the following steps:

[0085] (1) mixing the positive electrode material and the conductive agent by a first stirring process at a speed of 28 rpm for 13 minutes to obtain a mixed powder, and then infiltrating the mixed powder with water by a second stirring process at a speed of 15 rpm for 30 minutes to obtain a muddy first slurry with a solid content of 83 wt%. The mass ratio of the positive electrode material to the conductive agent in the first slurry is 93:6;

[0086] (2) After mixing the aqueous adhesive solution with a solid content of 19 wt %, the aqueous conductive agent solution with a solid content of 6 wt % and the first slurry obtained in step (1) by a third stirring process at a rotation speed of 28 rpm for 15 min, vacuum stirring at a rotation speed of 15 rpm and vacuum dispersion at a rotation speed of 650 rpm were simultaneously performed for 4.5 h under a vacuum degree of -0.085 MPa to obtain a muddy second slurry with a solid content of 72 wt %, wherein the mass ratio of the positive electrode main material, the conductive agent, the aqueous adhesive and the aqueous conductive agent in the second slurry was 93:6:2.5:4;

[0087] (3) After the aqueous adhesive solution and water obtained in step (2) are mixed by a fourth stirring process at a speed of 15 rpm for 30 min, vacuum stirring at a speed of 20 rpm and vacuum dispersion at a speed of 2800 rpm are simultaneously performed for 1.5 h at a vacuum degree of -0.096 MPa to obtain a lithium ion battery positive electrode slurry with a solid content of 60 wt%. The mass ratio of the positive electrode main material, the conductive agent, the aqueous adhesive and the aqueous conductive agent in the lithium ion battery positive electrode slurry is 93:6:4.8:4.

[0088] Example 4

[0089] This embodiment provides an aqueous homogenization process for a lithium-ion battery positive electrode system, the aqueous homogenization process comprising the following steps:

[0090] (1) mixing the positive electrode material and the conductive agent by a first stirring process at a speed of 30 rpm for 10 min to obtain a mixed powder, and then infiltrating the mixed powder with water by a second stirring process at a speed of 24 rpm for 20 min to obtain a muddy first slurry with a solid content of 80 wt %. The mass ratio of the positive electrode material to the conductive agent in the first slurry is 90:10;

[0091] (2) After mixing the aqueous adhesive solution with a solid content of 20 wt %, the aqueous conductive agent solution with a solid content of 5 wt % and the first slurry obtained in step (1) by a third stirring process at a rotation speed of 30 rpm for 10 min, vacuum stirring at a rotation speed of 28 rpm and vacuum dispersion at a rotation speed of 800 rpm were simultaneously performed for 3 h at a vacuum degree of -0.092 MPa to obtain a muddy second slurry with a solid content of 77 wt %. The mass ratio of the positive electrode main material, the conductive agent, the aqueous adhesive and the aqueous conductive agent in the second slurry was 90:10:1.2:7;

[0092] (3) After the aqueous adhesive solution and water obtained in step (2) are mixed by a fourth stirring process at a speed of 28 rpm for 13 min, vacuum stirring at a speed of 15 rpm and vacuum dispersion at a speed of 3000 rpm are simultaneously performed at a vacuum degree of -0.085 MPa for 1 h to obtain a lithium ion battery positive electrode slurry with a solid content of 50 wt%. The mass ratio of the positive electrode main material, the conductive agent, the aqueous adhesive and the aqueous conductive agent in the lithium ion battery positive electrode slurry is 90:10:4.2:7.

[0093] Example 5

[0094] This embodiment provides an aqueous homogenization process for a lithium-ion battery positive electrode system, the aqueous homogenization process comprising the following steps:

[0095] (1) mixing the positive electrode material and the conductive agent by a first stirring process at a speed of 15 rpm for 30 minutes to obtain a mixed powder, and then infiltrating the mixed powder with water by a second stirring process at a speed of 30 rpm for 10 minutes to obtain a muddy first slurry with a solid content of 85 wt%, wherein the mass ratio of the positive electrode material to the conductive agent in the first slurry is 99:0.5;

[0096] (2) After mixing the aqueous adhesive solution with a solid content of 15 wt %, the aqueous conductive agent solution with a solid content of 10 wt % and the first slurry obtained in step (1) by a third stirring process at a rotation speed of 15 rpm for 30 min, vacuum stirring at a rotation speed of 30 rpm and vacuum dispersion at a rotation speed of 500 rpm were simultaneously performed for 5 h under a vacuum degree of -0.1 MPa to obtain a muddy second slurry with a solid content of 70 wt %, wherein the mass ratio of the positive electrode main material, the conductive agent, the aqueous adhesive and the aqueous conductive agent in the second slurry was 99:2:1.2:3;

[0097] (3) After the aqueous adhesive solution, water and the second slurry obtained in step (2) are mixed by a fourth stirring process at a speed of 30 rpm for 10 min, vacuum stirring at a speed of 30 rpm and vacuum dispersion at a speed of 2500 rpm are simultaneously performed for 3 h at a vacuum degree of -0.088 MPa to obtain a lithium ion battery positive electrode slurry with a solid content of 56 wt%. The mass ratio of the positive electrode main material, the conductive agent, the aqueous adhesive and the aqueous conductive agent in the lithium ion battery positive electrode slurry is 99:2:4:3.

[0098] Example 6

[0099] This embodiment provides an aqueous slurrying process for a lithium-ion battery positive electrode system. Except that the solid content of the first slurry in step (1) is 76 wt %, the rest is the same as that of Example 1.

[0100] Example 7

[0101] This embodiment provides an aqueous slurrying process for a lithium-ion battery positive electrode system. Except that the solid content of the first slurry in step (1) is 90 wt %, the rest is the same as that of Example 1.

[0102] Example 8

[0103] This embodiment provides an aqueous slurrying process for a lithium-ion battery positive electrode system, which is the same as that of Example 1 except that the solid content of the second slurry in step (2) is 65 wt%.

[0104] Example 9

[0105] This embodiment provides an aqueous slurrying process for a lithium-ion battery positive electrode system, which is the same as that of embodiment 1 except that the solid content of the second slurry in step (2) is 80 wt%.

[0106] Example 10

[0107] This embodiment provides an aqueous slurrying process for a lithium-ion battery positive electrode system, which is the same as that of Example 1 except that the solid content of the aqueous adhesive solution in step (2) is 12 wt%.

[0108] Example 11

[0109] This embodiment provides an aqueous slurrying process for a lithium-ion battery positive electrode system, which is the same as that of Example 1 except that the solid content of the aqueous adhesive solution in step (2) is 25 wt%.

[0110] Example 12

[0111] This embodiment provides an aqueous slurrying process for a lithium-ion battery positive electrode system, which is the same as that of embodiment 1 except that the solid content of the aqueous conductive agent gel in step (2) is 3 wt%.

[0112] Example 13

[0113] This embodiment provides an aqueous slurrying process for a lithium-ion battery positive electrode system, which is the same as that of embodiment 1 except that the solid content of the aqueous conductive agent gel in step (2) is 15 wt%.

[0114] The fineness and viscosity of the lithium-ion battery positive electrode slurry obtained in the above examples were tested, and the test results are shown in Table 1;

[0115] The test method for the fineness of lithium-ion battery cathode slurry is to use a scraping fineness plate;

[0116] The viscosity of the positive electrode slurry for lithium-ion batteries is tested using a viscometer.

[0117] A lithium-ion battery was prepared using the lithium-ion battery positive electrode slurry obtained in the above embodiment. The preparation method is as follows: the slurry is coated on a foil and dried, and the prepared lithium-ion battery is subjected to a battery capacity test and a stability test by lamination. The test results are shown in Table 1. The test method is 1000 cycles at 0.5C.

[0118] Table 1

[0119] Fineness (μm) Viscosity (cp) Battery capacity (mAh / g) Capacity retention rate (%) Example 1 15 5000 138.2 96 Example 2 10 5500 136.5 96.5 Example 3 10 6000 133.5 99 Example 4 10 8000 130.4 99.3 Example 5 20 4000 139.4 96 Example 6 28 Unstable 112.9 84 Example 7 27 Unstable 115.3 86 Example 8 25 6200 118.5 88 Example 9 28 Unstable 114.6 85 Example 10 26 Unstable 119.4 88 Example 11 27 Unstable 113.8 87 Example 12 24 Unstable 121.2 89 Example 13 26 Unstable 117.5 84

[0120] From Table 1, we can get:

[0121] (1) The positive electrode slurry of the lithium ion battery prepared in Examples 1 to 5 has low fineness and high uniformity, and the prepared lithium ion battery has high capacity and capacity retention rate; in the aqueous slurry process of the positive electrode system of the lithium ion battery of the present invention, the positive electrode main material and the conductive agent are mixed in step (1), and then a small amount of water is added to wet it first, thereby avoiding the agglomeration of the mixed powder; in step (2), the aqueous adhesive glue, the aqueous conductive agent glue and the first slurry are mixed and scraped, and stirred and dispersed at an appropriate solid content. The solid content will not reach the kneading state, thus avoiding the agitator scraping against the cylinder wall and sticking to the cylinder during the kneading process, thereby avoiding the slurry sticking to the cylinder from being squeezed and rubbed in time, resulting in poor dispersion effect of the final lithium-ion battery positive electrode slurry; in step (2), the water-based adhesive glue, the water-based conductive agent glue and the first slurry are evenly dispersed through a one-step glue adding process, effectively reducing the investment cost of the slurry preparation process, shortening the time of the water-based slurrying process, improving the overall process efficiency, and effectively ensuring the stability and uniformity of the water-based positive electrode system slurry;

[0122] (2) By comparing Example 1 with Examples 6 and 7, it can be seen that the solid content of the first slurry in the present invention will affect the viscosity and fineness of the prepared lithium ion battery positive electrode slurry, and will also affect the capacity and stability of the lithium ion battery prepared with the lithium ion battery positive electrode slurry; when the solid content of the wetted mixed powder is low, that is, there is too much water, it will cause the viscosity of the lithium ion battery positive electrode slurry to be unstable, the fineness to increase, the battery capacity of the lithium ion battery to decrease, and the capacity retention rate to decrease. This is because the volume of the unwetted powder is large, and adding water to wet it can reduce the volume of the powder. If the moisture content of the wetted powder is excessive, part of the powder will agglomerate into larger particles. These over-wetted large particles will agglomerate into larger particles during stirring. On the rod or cylinder wall, these large particles may enter the slurry in the subsequent homogenization, resulting in large fineness of the final slurry, large slurry particles, poor capacity of the prepared battery, and rapid capacity decay; when the solid content of the first slurry is too high, the viscosity of the lithium-ion battery positive electrode slurry will be unstable, the fineness will increase, the battery capacity of the lithium-ion battery will decrease, and the capacity retention rate will decrease. This is because when the wetting liquid is less, the powder is not fully wetted, the powder volume is still large, and it will still agglomerate when the glue and conductive agent are added for the second time. In addition, part of the slurry cannot be dispersed on the rod, resulting in poor slurry dispersion effect, poor capacity of the prepared battery, and rapid capacity decay;

[0123] (3) By comparing Example 1 with Examples 8 and 9, it can be seen that the solid content of the second slurry in the present invention will affect the viscosity and fineness of the prepared lithium-ion battery positive electrode slurry, and will also affect the capacity and stability of the lithium-ion battery prepared with the lithium-ion battery positive electrode slurry; when the solid content of the second slurry is low, the viscosity and fineness of the lithium-ion battery positive electrode slurry will increase, the battery capacity of the lithium-ion battery will decrease, and the capacity retention rate will decrease. This is because the slurry viscosity is too low, the friction between the slurry particles is small, and the dispersion disk cannot disperse the agglomerated particles; when the solid content of the second slurry is high, the viscosity of the lithium-ion battery positive electrode slurry will be unstable, the fineness will increase, the battery capacity of the lithium-ion battery will decrease, and the capacity retention rate will decrease. This is because when the slurry viscosity is high, there will be phenomena such as slurry mud climbing the rod and sticking to the wall. The slurry on the rod and the cylinder wall cannot be dispersed, which will result in poor slurry dispersion effect, poor performance of the prepared battery capacity, and rapid capacity decay.

[0124] (4) By comparing Example 1 with Examples 10 and 11, it can be seen that the solid content of the aqueous adhesive solution in step (2) of the present invention will affect the viscosity and fineness of the prepared lithium ion battery positive electrode slurry, and will also affect the capacity and stability of the lithium ion battery prepared with the lithium ion battery positive electrode slurry; when the solid content of the aqueous adhesive solution is low, the viscosity of the lithium ion battery positive electrode slurry will be unstable, the fineness will increase, the battery capacity of the lithium ion battery will decrease, and the capacity retention rate will decrease. This is because the solution with a lower solid content contains a large amount of water. Adding part of the solution can achieve the target solid content, but the first and second slurries are The binder content in the adhesive may be too low, resulting in poor dispersion effect; when the solid content of the aqueous adhesive solution is too high, the viscosity of the positive electrode slurry of the lithium-ion battery will be unstable, and the battery capacity and capacity retention rate of the lithium-ion battery will be inconsistent. This is because the high solid content of the adhesive solution has high viscosity, low water content, high cohesion, relatively poor fluidity, and is not easy to penetrate. As a result, some particles in the slurry are coated with a large amount of binder, while some particles are less coated with binder. Particles coated with less binder are prone to agglomeration, resulting in poor slurry stability, which may lead to unstable surface density during coating and poor consistency in the electrical performance of the prepared battery.

[0125] (5) By comparing Example 1 with Examples 12 and 13, it can be seen that the solid content of the aqueous conductive agent glue in step (2) of the present invention will affect the viscosity and fineness of the prepared lithium ion battery positive electrode slurry, and will also affect the capacity and stability of the lithium ion battery prepared with the lithium ion battery positive electrode slurry; when the solid content of the aqueous conductive agent slurry is low, the viscosity of the lithium ion battery positive electrode slurry will be unstable, the fineness will increase, the battery capacity of the lithium ion battery will be reduced and the consistency will be poor, and the capacity retention rate will be reduced. This is because there is more solvent water in the low-solid aqueous slurry. When a certain proportion of conductive agent is added to the slurry, the glue needs to be reduced. Only when the amount of conductive agent is too high can the appropriate solid content of the slurry be achieved. If the amount of glue is reduced, the dispersion effect will be poor, resulting in unstable slurry and unstable surface density during coating, which will lead to poor battery performance. When the solid content of the aqueous conductive agent glue is too high, the viscosity of the positive electrode slurry of the lithium-ion battery will be unstable and the fineness will increase. The battery capacity of the lithium-ion battery will be reduced and the consistency will be poor, and the capacity retention rate will be reduced. This is because the viscosity of the conductive agent with high solid content is relatively high and the fluidity is poor. The conductive agent will re-agglomerate and the conductive agent cannot be evenly attached to the main materials. Some main materials will have more conductive agent and some places will have less, resulting in poor conductive effect.

[0126] In summary, the lithium ion battery positive electrode slurry prepared by the aqueous homogenization process of the lithium ion battery positive electrode system of the present invention has low particle size and high stability. The aqueous homogenization process is short in time, high in preparation efficiency, low in preparation cost, and has low requirements on the production environment and production equipment.

[0127] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and disclosure scope of the present invention.

Claims

1. A water system homogenization process for a lithium ion battery positive electrode system, characterized in that: The aqueous homogenization process comprises the following steps: (1) mixing a positive electrode main material and a conductive agent to obtain a mixed powder, and soaking the mixed powder with water to obtain a wet first slurry; (2) mixing the aqueous adhesive solution, the aqueous conductive agent solution and the first slurry obtained in step (1), and simultaneously performing vacuum stirring and vacuum dispersion to obtain a muddy second slurry; (3) mixing the aqueous adhesive solution, water, and the second slurry obtained in step (2), and then simultaneously performing vacuum stirring and vacuum dispersion to obtain a lithium-ion battery positive electrode slurry; Step (1) The solid content of the first slurry is 80-83 wt%; Step (2) The solid content of the second slurry is 70-77 wt %; The solid content of the aqueous conductive agent solution in step (2) is 5 to 10 wt %; The solid content of the aqueous adhesive solution in step (2) is 15 to 20 wt%.

2. The aqueous homogenization process according to claim 1, characterized in that: The mixing method in step (1) includes first stirring.

3. The aqueous homogenization process according to claim 2, characterized in that: The first stirring speed is 15-30 rpm and the stirring time is 10-30 min.

4. The aqueous homogenization process according to claim 1, characterized in that: The infiltration method in step (1) includes a second stirring.

5. The aqueous homogenization process according to claim 4, characterized in that: The second stirring is performed at a rotation speed of 15-30 rpm and for a time of 10-30 min.

6. The aqueous homogenization process according to claim 1, characterized in that: The positive electrode main material in step (1) includes any one of a ternary positive electrode material, lithium iron phosphate, elemental sulfur or lithium manganate, or a combination of at least two thereof.

7. The aqueous homogenization process according to claim 1, characterized in that: The conductive agent in step (1) includes any one of conductive carbon black, conductive graphite, acetylene black or Ketjen black, or a combination of at least two of them.

8. The aqueous homogenization process according to claim 1, characterized in that: In step (1), the mass ratio of the positive electrode main material to the conductive agent in the first slurry is (90-99):(0.5-10).

9. The aqueous homogenization process according to claim 1, characterized in that: The mixing method in step (2) includes a third stirring.

10. The aqueous homogenization process according to claim 9, characterized in that: The third stirring is performed at a rotation speed of 15 to 30 rpm and for a time of 10 to 30 minutes.

11. The aqueous homogenization process according to claim 1, characterized in that: The rotation speed of the vacuum stirring in step (2) is 15 to 30 rpm.

12. The aqueous homogenization process according to claim 1, characterized in that: The rotation speed of the vacuum dispersion in step (2) is 500 to 800 rpm.

13. The aqueous homogenization process according to claim 1, characterized in that: The vacuum degree of the vacuum stirring and vacuum dispersion in step (2) is -0.1 to -0.085 MPa.

14. The aqueous homogenization process according to claim 1, characterized in that: The time of vacuum stirring and vacuum dispersion in step (2) is 3 to 5 hours.

15. The aqueous homogenization process according to claim 1, characterized in that: The water-based adhesive solution in step (2) includes a water-based adhesive and water, and the water-based adhesive includes any one of polyvinylidene fluoride adhesive, styrene-butadiene rubber latex adhesive, carboxymethyl cellulose adhesive, polyacrylic acid adhesive, polyacrylonitrile adhesive or polyacrylate adhesive, or a combination of at least two thereof.

16. The aqueous homogenization process according to claim 1, characterized in that: The aqueous conductive agent glue in step (2) includes an aqueous conductive agent and water, and the aqueous conductive agent includes any one of carbon nanofibers, carbon nanotubes or graphene, or a combination of at least two of them.

17. The aqueous homogenization process according to claim 1, characterized in that: In step (2), the mass ratio of the positive electrode main material, the conductive agent, the aqueous adhesive and the aqueous conductive agent in the second slurry is (90-99):(0.5-10):(1-3):(0.5-10).

18. The aqueous homogenization process according to claim 1, characterized in that: The mixing method in step (3) includes a fourth stirring.

19. The aqueous homogenization process according to claim 18, characterized in that: The fourth stirring process has a rotation speed of 15-30 rpm and a stirring time of 10-30 min.

20. The aqueous homogenization process according to claim 1, characterized in that: The rotation speed of the vacuum stirring in step (3) is 15 to 30 rpm.

21. The aqueous homogenization process according to claim 1, characterized in that: The rotation speed of the vacuum dispersion in step (3) is 2500-3000 rpm.

22. The aqueous homogenization process according to claim 1, characterized in that: The vacuum degree of the vacuum stirring and vacuum dispersion in step (3) is -0.1 to -0.085 MPa.

23. The aqueous homogenization process according to claim 1, characterized in that: The time of the vacuum stirring and vacuum dispersion in step (3) is 1 to 3 hours.

24. The aqueous homogenization process according to claim 1, characterized in that: The water-based adhesive solution in step (3) is the same as the water-based adhesive solution in step (2).

25. The aqueous homogenization process according to claim 1, characterized in that: The solid content of the lithium-ion battery positive electrode slurry in step (3) is 50 to 60 wt%.

26. The aqueous homogenization process according to claim 1, characterized in that: The viscosity of the lithium-ion battery positive electrode slurry in step (3) is 4000 to 8000 cp.

27. The aqueous homogenization process according to claim 1, characterized in that: The fineness of the lithium-ion battery positive electrode slurry in step (3) is 10 to 20 μm.

28. The aqueous homogenization process according to claim 1, characterized in that: The mass ratio of the positive electrode main material, the conductive agent, the aqueous adhesive and the aqueous conductive agent in the lithium ion battery positive electrode slurry in step (3) is (90-99): (0.5-10): (3-10): (0.5-10).

29. The aqueous homogenization process according to claim 1, characterized in that: The aqueous homogenization process comprises the following steps: (1) mixing the positive electrode material and the conductive agent by a first stirring process at a speed of 15 to 30 rpm for 10 to 30 minutes to obtain a mixed powder, and then infiltrating the mixed powder with water by a second stirring process at a speed of 15 to 30 rpm for 10 to 30 minutes to obtain a first slurry with a wet solid content of 80 to 83 wt %, wherein the mass ratio of the positive electrode material to the conductive agent in the first slurry is (90 to 99):(0.5 to 10); (2) After mixing the aqueous adhesive solution with a solid content of 15 to 20 wt %, the aqueous conductive agent solution with a solid content of 5 to 10 wt % and the first slurry obtained in step (1) by a third stirring process at a rotation speed of 15 to 30 rpm for 10 to 30 min, vacuum stirring at a rotation speed of 15 to 30 rpm and vacuum dispersion at a rotation speed of 500 to 800 rpm are simultaneously performed for 3 to 5 h under a vacuum degree of -0.1 to -0.085 MPa to obtain a muddy second slurry with a solid content of 70 to 77 wt %, wherein the mass ratio of the positive electrode main material, the conductive agent, the aqueous adhesive and the aqueous conductive agent in the second slurry is (90 to 99):(0.5 to 10):(1 to 3):(0.5 to 10); (3) After the aqueous adhesive solution and water obtained in step (2) are mixed by a fourth stirring process at a rotation speed of 15 to 30 rpm for 10 to 30 min, vacuum stirring at a rotation speed of 15 to 30 rpm and vacuum dispersion at a rotation speed of 2500 to 3000 rpm are simultaneously performed for 1 to 3 h under a vacuum degree of -0.1 to -0.085 MPa to obtain a lithium ion battery positive electrode slurry with a solid content of 50 to 60 wt%, a viscosity of 4000 to 8000 cp and a fineness of 10 to 20 μm. The mass ratio of the positive electrode main material, the conductive agent, the aqueous adhesive and the aqueous conductive agent in the lithium ion battery positive electrode slurry is (90 to 99): (0.5 to 10): (3 to 10): (0.5 to 10).

30. A positive electrode slurry for a lithium ion battery, characterized in that: The lithium-ion battery positive electrode slurry is prepared by the aqueous homogenization process according to any one of claims 1 to 29.

31. A lithium ion battery, characterized in that: The lithium-ion battery comprises the lithium-ion battery positive electrode slurry according to claim 30.