Inorganic compound slurry and lithium battery positive electrode slurry containing same

Abstract

The invention relates to the technical field of lithium batteries, and discloses inorganic compound slurry and lithium battery positive electrode slurry containing the same. The inorganic compound slurry comprises inorganic compound solid particles, a dispersing agent A and a dispersing agent B, wherein the dispersing agent A is selected from one or more of amine compounds containing ether chains; the dispersing agent B is selected from one or more of phosphoric acid compounds containing ether chains. The inorganic compound slurry contains the dispersing agent A and the dispersing agent B at the same time, the dispersing agent A and the dispersing agent B are compounded, the synergistic modification effect on the surfaces of inorganic compound solid particles is achieved, and when the inorganic compound slurry is mixed into the lithium battery positive electrode slurry, the agglomeration effect between the solid particles can be reduced; and meanwhile, the problem that the viscosity is sharply increased after the inorganic compound slurry is mixed into the positive electrode slurry is also solved.

Description

An inorganic compound slurry and a lithium battery cathode slurry containing the same. Technical Field

[0001] This invention relates to the field of lithium battery technology, specifically to inorganic compound slurries and lithium battery cathode slurries containing them. Background Technology

[0002] Lithium-ion battery slurry is a key slurry mixture used in the manufacture of the positive and negative electrodes of lithium-ion batteries. It mainly includes two types: positive electrode slurry and negative electrode slurry. The positive electrode slurry is composed of oxide active materials, conductive agents, and binders, while the negative electrode slurry mainly includes graphite-based materials, conductive agents, and binders. This slurry is coated or sprayed onto the current collector, and then undergoes subsequent processes such as drying, rolling, and slitting to finally assemble into a lithium-ion battery.

[0003] In lithium-ion battery manufacturing, the slurry preparation process is a critical upstream step, as the quality of the slurry directly determines the battery's production efficiency and overall electrochemical performance. To improve battery safety, oxides are often introduced into the positive electrode slurry in slurry form. Studies have shown that at lower addition levels, smaller particle sizes of oxides are more conducive to improving battery performance. However, as the particle size decreases, the specific surface area of ​​oxides increases significantly, leading to higher surface energy and a tendency to agglomerate. For example, adding only 2% of the total solids and 150 nm of oxide slurry to the positive electrode slurry can result in an increase of over 150% in the total specific surface area of ​​the positive electrode material. This drastic increase in specific surface area easily promotes the adsorption and agglomeration of oxide particles with the commonly used binder, polyvinylidene fluoride (PVDF).

[0004] Furthermore, since the positive electrode slurry itself has a high solid content and high viscosity, the introduction of nano-scale oxides will further cause the viscosity of the system to rise sharply, resulting in unstable rheological properties of the slurry, which in turn will have an adverse effect on the uniformity of the subsequent coating process and the performance of the finished electrode. Summary of the Invention

[0005] The purpose of this invention is to overcome the problem of viscosity surge after inorganic compound slurry is mixed into positive electrode slurry in the prior art. It provides inorganic compound slurry and lithium battery positive electrode slurry containing it. By adding reasonable dispersants to modify the inorganic compound slurry, when it is mixed into lithium battery positive electrode slurry, it can effectively inhibit the agglomeration of solid particles and PVDF, and keep the solid particles uniformly dispersed in the positive electrode slurry system. At the same time, it also solves the problem of viscosity surge after inorganic compound slurry is mixed into positive electrode slurry.

[0006] To achieve the above objectives, a first aspect of the present invention provides an inorganic compound slurry comprising inorganic compound solid particles, dispersant A, and dispersant B; wherein, dispersant A is selected from one or more amine compounds containing ether chains; and dispersant B is selected from one or more phosphate compounds containing ether chains.

[0007] The second aspect of the present invention provides the application of the inorganic compound slurry as described in the first aspect above in the preparation of lithium battery cathode slurry.

[0008] A third aspect of the present invention provides a lithium battery positive electrode slurry containing the inorganic compound slurry described in the first aspect above.

[0009] A fourth aspect of the present invention provides a lithium battery positive electrode, wherein the lithium battery positive electrode is prepared from the positive electrode slurry described in the third aspect above.

[0010] The beneficial technical effects achieved by the present invention through the above technical solution are as follows: The inorganic compound slurry of the present invention contains dispersant A and dispersant B. Through the compounding of dispersant A and dispersant B, the surface of the inorganic compound solid particles is synergistically modified, which can better maintain the dispersion uniformity and stability of the solid particles. When the inorganic compound slurry of the present invention is mixed into the positive electrode slurry of lithium battery, it reduces the agglomeration between solid electrolytes and the agglomeration between nano-sized particles and PVDF, and keeps the solid particles uniformly dispersed in the positive electrode slurry system. At the same time, while ensuring the fineness of the positive electrode slurry, it also solves the problem of viscosity surge after the inorganic compound slurry is mixed into the positive electrode slurry. Detailed Implementation

[0011] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0012] The first aspect of the present invention provides an inorganic compound slurry, which includes inorganic compound solid particles, dispersant A and dispersant B; wherein, dispersant A is selected from one or more amine compounds containing ether chains; and dispersant B is selected from one or more phosphate compounds containing ether chains.

[0013] According to the present invention, the inorganic compound slurry contains dispersant A and dispersant B. Through the compounding of dispersant A and dispersant B, the surface of the inorganic compound solid particles is synergistically modified. When it is mixed into the lithium battery cathode slurry, it can reduce the agglomeration between solid particles and the agglomeration of nano-sized particles and PVDF. At the same time, while ensuring the fineness of the cathode slurry, it also solves the problem of the viscosity surge after the inorganic compound slurry is mixed into the cathode slurry.

[0014] According to some embodiments of the present invention, the weight ratio of dispersant A to dispersant B is 1:0.2-1:5, for example, it can be 1:0.2, 1:0.4, 1:0.5, 1:0.8, 1:1, 1:1.2, 1:1.5, 1:1.7, 1:1.8, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, or any value within the range of any two values, preferably 1:0.5-1:2.

[0015] According to the present invention, by controlling the weight ratio of dispersant A and dispersant B within the above-mentioned range, the agglomeration effect between solid particles can be further reduced; the agglomeration effect between nano-sized particles and PVDF can also be further reduced, and the problem of viscosity surge after inorganic compound slurry is mixed into positive electrode slurry can be further solved.

[0016] According to some embodiments of the present invention, based on 100 parts by weight of the inorganic compound solid particles, the content of dispersant A is 0.2-5 parts by weight; the content of dispersant B is 0.2-5 parts by weight.

[0017] According to some embodiments of the present invention, the molecular weight of the dispersant A is 400-20000 g / mol, for example, it can be 400 g / mol, 600 g / mol, 800 g / mol, 1000 g / mol, 1200 g / mol, 1500 g / mol, 1800 g / mol, 2000 g / mol, 2200 g / mol, 2500 g / mol, 2800 g / mol, 3000 g / mol, 3500 g / mol, 3700 g / mol, 4000 g / mol, 4200 g / mol, 4500 g / mol, 4800 g / mol, 5000 g / mol, 5500 g / mol, 6000 g / mol, 6500 g / mol, 7000 g / mol, 7500 g / mol, 8000 g / mol, 8500 g / mol, 9000 g / mol, 10000 g / mol, etc. The values ​​are 12000 g / mol, 15000 g / mol, 18000 g / mol, 20000 g / mol, and any value within the range of any two values, preferably 1000-5000 g / mol.

[0018] According to some embodiments of the present invention, the molecular weight of the dispersant B is 400-20000 g / mol, for example, it can be 400 g / mol, 600 g / mol, 800 g / mol, 1000 g / mol, 1200 g / mol, 1500 g / mol, 1800 g / mol, 2000 g / mol, 2200 g / mol, 2500 g / mol, 2800 g / mol, 3000 g / mol, 3500 g / mol, 3700 g / mol, 4000 g / mol, 4200 g / mol, 4500 g / mol, 4800 g / mol, 5000 g / mol, 5500 g / mol, 6000 g / mol, 6500 g / mol, 7000 g / mol, 7500 g / mol, 8000 g / mol, 8500 g / mol, 9000 g / mol, 10000 g / mol, etc. The values ​​are 12000 g / mol, 15000 g / mol, 18000 g / mol, 20000 g / mol, and any value within the range of any two values, preferably 1000-5000 g / mol.

[0019] According to the present invention, the molecular weights of dispersant A and dispersant B are within the above-mentioned range, which can further suppress the agglomeration of solid particles and PVDF, and keep the solid particles more uniformly dispersed in the positive electrode slurry system. At the same time, it further solves the problem of viscosity surge after inorganic compound slurry is mixed into positive electrode slurry.

[0020] According to some embodiments of the present invention, the ether chain in dispersant A and / or dispersant B is an ether bond containing repeating units.

[0021] Preferably, the ether chains in dispersant A and / or dispersant B are ether bonds containing two different types of repeating units.

[0022] More preferably, the ether chains in dispersant A and / or dispersant B contain PPO and PEO segments.

[0023] According to some embodiments of the present invention, the ether-containing amine compound is selected from one or more of the structures shown in formulas I-1 to I-5; , Formula I-1; , Formula I-2; , Formula I-3; , Formula I-4; Equation I-5; where R1-R 23 Each substituent is independently selected from H, C1-C6 alkyl or alkoxy chains, and at least one of the substituents in each structure is an alkoxy chain; n1-n 10 Each integer is independently selected from 1 to 10, such as 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10.

[0024] According to some embodiments of the present invention, the alkoxy chain has the structure shown in formula (1): Equation (1); where R a and R b Each independently is C2-C 10 Alkylene, preferably C2-C3 alkylene; X is hydrogen or C1-C6 alkyl; m1 and m2 are each independently an integer from 2 to 50, for example 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 18, 20, 25, 30, 35, 40, 45, 50, and any value in the range of any two values, preferably an integer from 4 to 10.

[0025] According to the present invention, C2-C 10 Specific examples of alkylene groups include, but are not limited to: methylene, ethylene, propylene, butylene, pentylene, hexylene, octylene, decylene, 1-methylethylene, 2-methylethylene, 2-methylpropylene, 1-ethylethylene, etc., preferably methylene, ethylene, or propylene.

[0026] According to the present invention, specific examples of C1-C6 alkyl groups include, but are not limited to: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, isohexyl, sec-hexyl, neohexyl, preferably methyl, ethyl, n-propyl or isopropyl.

[0027] According to some embodiments of the present invention, the dispersant B is a phosphate compound containing an ether chain selected from one or more of the structures shown in formulas II-1 to II-3; Formula II-1; Formula II-2; Equation II-3; where R 1 -R 12 Each is independently selected from H, C1-C6 alkyl or the structure shown in formula (2); and at least one of the substituents in each structure is H, and at least one is the structure shown in formula (2); Equation (2); where R c and R d Each independently is C2-C 10 Alkylene, preferably C2-C3 alkylene; Y is hydrogen or C1-C6 alkyl; m3 and m4 are each independently an integer from 2 to 50, for example 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 18, 20, 25, 30, 35, 40, 45, 50, and any value in the range of any two values, preferably an integer from 4 to 10.

[0028] According to some embodiments of the present invention, in the molecular structure of the ether-chain-containing phosphoric acid compound, at least one phosphorus atom is simultaneously attached to two -OH groups.

[0029] According to the present invention, the molecular structure of the ether-chain-containing phosphoric acid compound has at least one phosphorus atom simultaneously connected to two -OH groups, that is, the end group connected to phosphoric acid in the molecular structure of dispersant B contains two H. This structure is more likely to interact with the surface of inorganic compound particles and is also more conducive to weakening the agglomeration between particles, thereby further ensuring the fineness stability of the slurry.

[0030] According to some preferred embodiments of the present invention, in formula II-1, R 1 R 2 and R 3 Two of them are hydrogen, and R 1 R 2 and R 3 They are not both hydrogen.

[0031] According to some preferred embodiments of the present invention, in formula II-2, R 4 and R 5As a group, R 6 and R 7 There is one group, in which one group is also hydrogen, and R 4 R 5 R 6 and R 7 They are not both hydrogen.

[0032] According to some preferred embodiments of the present invention, in formula II-3, R 8 and R 9 As a group, R 11 and R 12 There is one group, in which one group is also hydrogen, and R 8 R 9 R 10 R 11 and R 12 They are not both hydrogen.

[0033] According to some embodiments of the present invention, the particle size of the inorganic compound solid particles is 10-500 nm, for example, 10 nm, 12 nm, 15 nm, 18 nm, 20 nm, 25 nm, 30 nm, 50 nm, 80 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, and any value within the range of any two values.

[0034] According to some embodiments of the present invention, the inorganic compound in the inorganic compound solid particles is selected from one or more of solid electrolytes, inorganic salt compounds, and metal oxides.

[0035] According to some preferred embodiments of the present invention, the solid electrolyte is selected from oxide solid electrolytes.

[0036] More preferably, the oxide solid electrolyte is selected from LiSICON type electrolyte, NASICON type electrolyte, perovskite type electrolyte, garnet type electrolyte, anti-perovskite electrolyte, lithium phosphate aluminum type electrolyte, and Li 1-x1 Ti 1-x1 M x1 OPO4, Li 1+x2 H 1-x2 Al(PO4)O 1-y1 M' 2y1 LiAlPO4M'' x3 (OH)1 x3One or more of the following; wherein M is selected from one or more of Nb, Ta and Sb; M' and M'' are each independently selected from one or more of F, Cl, Br and I; 0≤x1≤0.7, 0≤x2<1, 0≤x3<1, 0<y1<0.1.

[0037] According to some preferred embodiments of the present invention, the inorganic salt compound is selected from one or more of titanates, phosphates, silicates and carbonates.

[0038] According to some preferred embodiments of the present invention, the metal oxide is selected from one or more of titanium dioxide, silicon dioxide, aluminum oxide, and cerium dioxide.

[0039] According to some embodiments of the present invention, the inorganic compound slurry further includes an additive C, wherein the additive C is selected from one or more small molecule organic compounds; the small molecule organic compounds contain N-containing groups that can form coordination interactions with metal ions.

[0040] According to the present invention, further adding small molecule organic matter to the inorganic compound slurry can coordinate with the exposed metal ions on the particle surface that have not reacted with dispersant A, thereby weakening their interaction with PVDF.

[0041] According to some embodiments of the present invention, the molecular weight of the small molecule organic compound is 40-1000 g / mol.

[0042] According to some embodiments of the present invention, based on 100 parts by weight of the inorganic compound solid particles, the content of the additive C is 0.2-5 parts by weight, preferably 1-3 parts by weight.

[0043] According to some embodiments of the present invention, the small molecule organic compound is selected from one or more of compounds containing one nitrogen atom, compounds containing two nitrogen atoms, compounds containing three nitrogen atoms, and cyano compounds.

[0044] According to the present invention, the small molecule organic compound is preferably a compound containing three nitrogen atoms, a cyano group or other compound with strong coordination effect. Experiments have shown that it can help the dispersant to further stabilize with the metal ions on the surface of the solid electrolyte through coordination, further reduce its interaction with PVDF, and thus reduce the viscosity surge after it is incorporated into the positive electrode slurry.

[0045] According to some embodiments of the present invention, the compound containing one nitrogen atom is selected from one or more of primary amines, secondary amines, and tertiary amines.

[0046] Preferably, the compound containing one nitrogen atom is selected from one or more of octylamine and its derivatives, pyridine and its derivatives, triethylamine and its derivatives, and N,N-dimethylaniline and its derivatives.

[0047] According to some embodiments of the present invention, the compound containing two nitrogen atoms is selected from one or more of pyridazine and its derivatives.

[0048] According to some embodiments of the present invention, the compound containing three nitrogen atoms is selected from one or more of benzotriazole and / or methylbenzotriazole.

[0049] According to some embodiments of the present invention, the cyano compound is selected from one or more of acetonitrile, benzonitrile and their derivatives.

[0050] According to some embodiments of the present invention, the inorganic compound slurry further includes a solvent selected from one or more of N-methylpyrrolidone (NMP), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA), methanol, ethanol, acetone, acetonitrile, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, ethylene carbonate, propylene carbonate, octane, isooctane, petroleum ether, cyclohexane, carbon tetrachloride, trichloroethylene, carbon disulfide, toluene, benzene, dichloromethane, chloroform, diethyl ether, ethyl acetate, and acetone.

[0051] According to some embodiments of the present invention, based on 100 parts by weight of the inorganic compound solid particles, the content of the solvent is 100-10000 parts by weight.

[0052] The present invention also provides a method for preparing an inorganic compound slurry, the method comprising: mixing an inorganic compound with a solvent, a dispersant A, a dispersant B and an optional auxiliary agent C to obtain an inorganic compound slurry.

[0053] According to some preferred embodiments of the present invention, the preparation method includes: first mixing an inorganic compound with a solvent, grinding the mixture, then adding dispersant A, then optionally adding auxiliary agent C, mixing well, and then adding dispersant B.

[0054] According to some embodiments of the present invention, the mass ratio of inorganic compound solid particles, solvent, dispersant A, dispersant B and auxiliary agent C is 1:1-100:0.002-0.05:0.002-0.05:0.002-0.05.

[0055] The second aspect of the present invention provides the application of the inorganic compound slurry as described in the first aspect above in the preparation of lithium battery cathode slurry.

[0056] According to the present invention, the above-mentioned lithium battery positive electrode slurry can be used to prepare electrodes and battery cells.

[0057] A third aspect of the present invention provides a lithium battery positive electrode slurry containing the inorganic compound slurry described in the first aspect above.

[0058] According to the present invention, in addition to the inorganic compound slurry described in the first aspect, the lithium battery positive electrode slurry may optionally contain positive electrode active materials, conductive agents, binders, dispersants, and other components used in the art for positive electrode slurries. For example, the positive electrode active material may include, but is not limited to, lithium transition metal oxides (such as lithium cobalt oxide, lithium iron phosphate, ternary materials, etc.); the conductive agent may include, but is not limited to, conductive carbon black, carbon nanotubes, graphene, etc.; and the binder may include, but is not limited to, polyvinylidene fluoride, sodium carboxymethyl cellulose, etc.

[0059] According to some embodiments of the present invention, the amount of inorganic compound slurry added is 0.1-5 wt%, based on the total mass of solids in the lithium battery cathode slurry.

[0060] According to some embodiments of the present invention, the fineness of the lithium battery positive electrode slurry is no greater than 80 μm, preferably 30-70 μm.

[0061] According to the present invention, the fineness of the lithium battery cathode slurry is measured using a scraper fineness meter.

[0062] In industries such as coatings, inks, ceramics, and batteries, "slurry fineness" generally refers to the fineness and particle size distribution of solid particles in a slurry after they are dispersed in a liquid medium. It is an important indicator for measuring the dispersion / grinding effect and refers to the approximate size of the largest particle in the slurry. For example, when the slurry fineness is 20μm, it usually means that the vast majority of particles in the slurry are smaller than 20μm, and the largest particle does not exceed 20μm (or is within this order of magnitude).

[0063] According to some embodiments of the present invention, the viscosity increase of the lithium battery cathode slurry over 12 hours is no more than 100%.

[0064] A fourth aspect of the present invention provides a lithium battery positive electrode, wherein the lithium battery positive electrode is prepared from the positive electrode slurry described in the third aspect above.

[0065] The present invention will be described in detail below through embodiments. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0066] Unless otherwise specified in the following examples and comparative examples, all conditions were performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments used, unless otherwise specified, are all commercially available products.

[0067] Test method for fineness of lithium battery cathode slurry: According to GB / T 6753.1-2007 Determination of grinding fineness of paints, varnishes and printing inks, a scraper fineness meter is used for testing. Specifically: (1) Instrument: The fineness meter is generally composed of a fineness plate and a scraper. A scraper fineness meter with a range of 100μm is generally used for lithium-ion battery slurry.

[0068] (2) Operating steps: Place the thoroughly cleaned and dried scraper on a flat, level, non-slip surface; drip enough sample into the deepest part of the groove, i.e. the part with the largest scale value, and let the sample overflow slightly; hold the scraper with your thumbs and forefingers, place the scraper blade horizontally at the part with the largest scale value on the scraper, so that the long side of the scraper is parallel to the wide side of the scraper and in perpendicular contact with the scraper surface, and scrape the scraper from the part with the largest scale value to the part with the smallest scale value within 1-2 seconds; immediately after scraping the sample (within 5 seconds), make your line of sight at a 20°-30° angle to the surface of the groove, observe the part in the groove where the particles are evenly exposed, and record the corresponding scale value.

[0069] (3) Reading: Observe the first densely packed particles on the sample, especially the area containing 5-10 particles within a 3mm strip. Scattered particles above the densely packed points can be ignored. Then determine the scale at the upper limit of the secondary strip, which is the fineness of the test sample. For a fineness plate with a 100μm range, the reading accuracy is 5μm. Calculate the average of the three measurements and record the test results with the corresponding accuracy for the range.

[0070] Viscosity test method: According to GB / T 22235-2008 "Determination of viscosity of liquids", a rotational viscometer with a 64# rotor and a rotation speed of 60 rpm was used for testing.

[0071] Example 1 (1) The lithium aluminum titanium phosphate (LATP) slurry (containing LATP and solvent NMP) was ground to 150 nm using a sand mill and discharged after a solid content of 20.0 wt%; (2) 5 kg of LATP slurry was taken and mechanically dispersed at 600 rpm. 10 g of dispersant A was added and stirred for 30 min. Then 10 g of auxiliary agent C benzotriazole was added and stirred for another 30 min. Then 10 g of dispersant B was added. The amount of dispersant A, dispersant B and auxiliary agent C added were all 1.0 wt% of LATP. After stirring for another 30 min, an inorganic compound slurry was obtained. The above dispersant A adopts the structure shown in Formula I-3, where n3=8, n4=8; R7-R 11 All adopt the structure shown in formula (3); the molecular weight of dispersant A is 4065 g / mol; Equation (3); The above-mentioned dispersant B adopts the structure shown in Equation II-3, wherein R 8 and R 9 Both are H, R10 -R 12 All adopt the structure shown in formula (4); the molecular weight of dispersant B is 3444 g / mol; Equation (4).

[0072] Example 2: An inorganic compound slurry was prepared according to the method of Example 1, except that the dispersant A added in step (2) adopted the structure shown in Formula I-1, where n1=8, and R1 and R2 both adopted the structure shown in Formula (5); the molecular weight of dispersant A was 4005 g / mol. Equation (5).

[0073] Example 3 Inorganic compound slurry was prepared according to the method of Example 1, except that the dispersant B added in step (2) adopted the structure shown in formula (6) and the molecular weight of dispersant B was 3200 g / mol. Equation (6).

[0074] Example 4: Inorganic compound slurry was prepared according to the method of Example 1, except that benzotriazole was not added in step (2).

[0075] Example 5: An inorganic compound slurry was prepared according to the method of Example 1, except that the auxiliary agent C added in step (2) was octadecylamine.

[0076] Example 6: An inorganic compound slurry was prepared according to the method of Example 1, except that LATP in step (1) was replaced with BaTiO3.

[0077] Comparative Example 1 prepared an inorganic compound slurry according to the method of Example 1, except that in step (2), dispersant B was not added, and the amount of dispersant A added was 2 wt% of LATP, and the amount of auxiliary agent C benzotriazole added was 1 wt% of LATP.

[0078] Comparative Example 2 prepared an inorganic compound slurry according to the method of Example 1, except that in step (2), dispersant A was not added, and the amount of dispersant B added was 2 wt% of LATP, and the amount of auxiliary agent C benzotriazole added was 1 wt% of LATP.

[0079] Comparative Example 3 prepared an inorganic compound slurry according to the method of Example 1, except that in step (2), dispersant B and auxiliary agent C benzotriazole were not added, and the amount of dispersant A added was 3 wt% of LATP.

[0080] Comparative Example 4 prepared an inorganic compound slurry according to the method of Example 1, except that in step (2), dispersant A and auxiliary agent C were not added, and the amount of dispersant B added was 3 wt% of LATP.

[0081] Preparation of lithium-ion battery cathode slurry for test example: Take 10.85g of PVDF solution with 5% solid content (solvent is NMP), add 3.8g of single-walled carbon nanotube solution with 0.4% solid content, and disperse at 1800rpm for 30min using a dual planetary defoamer; then add 7.07g of multi-walled carbon nanotube solution with 5.375% solid content, and disperse at 1800rpm for 30min; then add 77.4g of LiNi cathode material. 0.9 Co 0.05 Mn 0.05 O2 and 0.885g of conductive agent SP were mixed and added in three equal portions, with each addition dispersed for 30 minutes. Then, 0.12g of the inorganic compound slurry prepared in the above examples and comparative examples (the added inorganic compound slurry accounted for 2wt% of the solids in the positive electrode slurry) was added. After dispersing at 1800rpm for 30 minutes, N-methylpyrrolidone (NMP) was added to adjust the viscosity of the slurry to approximately 4500mPa. After step 's', the material is discharged.

[0082] Fineness and viscosity tests were performed on the initial fresh lithium battery cathode slurry to obtain the initial viscosity, denoted as η0. After standing at room temperature for 12 hours, the viscosity was tested again to obtain the 12-hour viscosity, denoted as η1. The formula for calculating the 12-hour viscosity increase A is as follows: A = (η1 - η0) / η0 × 100%; where A represents the 12-hour viscosity increase; η0 represents the initial viscosity; and η1 represents the 12-hour viscosity.

[0083] The fineness and 12-hour viscosity increase of the lithium battery cathode slurry prepared from the inorganic compound slurries obtained in Examples 1-6 and Comparative Examples 1-4 are shown in Table 1.

[0084] According to the above testing method, when the fineness of the lithium battery cathode slurry is >80μm and the viscosity increase over 12 hours is >100%, it is considered to exceed the standard.

[0085] Table 1

[0086] As shown in Table 1, the lithium battery cathode slurry prepared using the inorganic compound slurry obtained in Examples 1-6 of this invention has a fineness of no more than 80 μm and a viscosity increase of no more than 100% over 12 hours. This indicates that while ensuring the fineness of the lithium battery cathode slurry, it also solves the problem of viscosity surge that easily occurs after inorganic compound slurry is mixed into the cathode slurry. A comparison of Example 6 and Example 1 shows that the LATP dispersant ratio is also suitable for the BaTiO3 slurry system.

[0087] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. An inorganic compound slurry, characterized in that, The inorganic compound slurry comprises inorganic compound solid particles, dispersant A, and dispersant B; wherein, dispersant A is selected from one or more amine compounds containing ether chains; and dispersant B is selected from one or more phosphate compounds containing ether chains.

2. The inorganic compound slurry according to claim 1, wherein, The weight ratio of dispersant A to dispersant B is 1:0.2-1:5, preferably 1:0.5-1:2; preferably, based on 100 parts by weight of the inorganic compound solid particles, the content of dispersant A is 0.2-5 parts by weight, and the content of dispersant B is 0.2-5 parts by weight.

3. The inorganic compound slurry according to claim 1 or 2, wherein, The ether chains in dispersant A and / or dispersant B are ether bonds containing repeating units; preferably, the ether chains in dispersant A and / or dispersant B are ether bonds containing two different types of repeating units; more preferably, the ether chains in dispersant A and / or dispersant B contain PPO segments and PEO segments; and / or, the molecular weight of dispersant A is 400-20000 g / mol, preferably 1000-5000 g / mol; and / or, the molecular weight of dispersant B is 400-20000 g / mol, preferably 1000-5000 g / mol.

4. The inorganic compound slurry according to any one of claims 1-3, wherein, The amine compounds containing ether chains are selected from one or more of the structures shown in formulas I-1 to I-5; Equation I-1; Equation I-2; Equation I-3; Equation I-4; Equation I-5; where R1-R 23 Each substituent is independently selected from H, C1-C6 alkyl or alkoxy chains, and at least one of the substituents in each structure is an alkoxy chain; n1-n 10 Each integer is independently selected from 1 to 10.

5. The inorganic compound slurry according to claim 4, wherein, The alkoxy chain has the structure shown in formula (1): Equation (1); Among them, R a and R b Each independently is C2-C 10 Alkylene, preferably C2-C3 alkylene; X is hydrogen or C1-C6 alkyl; m1 and m2 are each independently an integer from 2 to 50, preferably an integer from 4 to 10.

6. The inorganic compound slurry according to any one of claims 1-5, wherein, The ether-containing phosphate compound is selected from one or more of the structures shown in formulas II-1 to II-3; Formula II-1; Formula II-2; Equation II-3; where R 1 -R 12 Each is independently selected from H, C1-C6 alkyl or the structure shown in formula (2); and at least one of the substituents in each structure is H, and at least one is the structure shown in formula (2); Equation (2); where R c and R d Each independently is C2-C 10 Alkylene, preferably C2-C3 alkylene; Y is hydrogen or C1-C6 alkyl; m3 and m4 are each independently an integer from 2 to 50, preferably an integer from 4 to 10; preferably, in the molecular structure of the ether-chain-containing phosphoric acid compound, at least one phosphorus atom is simultaneously attached to two -OH groups.

7. The inorganic compound slurry according to any one of claims 1-6, wherein, The inorganic compound solid particles have a particle size of 10-500 nm; and / or, the inorganic compound in the inorganic compound solid particles is selected from one or more of solid electrolytes, inorganic salt compounds, and metal oxides; preferably, the solid electrolyte is selected from oxide solid electrolytes; more preferably, the oxide solid electrolyte is selected from LiSICON type electrolytes, NASICON type electrolytes, perovskite type electrolytes, garnet type electrolytes, anti-perovskite type electrolytes, lithium phosphate aluminum type electrolytes, and Li 1-x1 Ti 1-x1 M x1 OPO4, Li 1+ x2 H 1-x2 Al(PO4)O 1-y1 M' 2y1 LiAlPO4M'' x3 (OH)1 x3 One or more of the following: wherein M is selected from one or more of Nb, Ta, and Sb; M' and M'' are each independently selected from one or more of F, Cl, Br, and I; 0≤x1≤0.7, 0≤x2<1, 0≤x3<1, 0<y1<0.1; preferably, the inorganic salt compound is selected from one or more of titanates, phosphates, silicates, and carbonates; preferably, the metal oxide is selected from one or more of titanium dioxide, silicon dioxide, aluminum oxide, and cerium dioxide.

8. The inorganic compound slurry according to any one of claims 1-7, wherein, The inorganic compound slurry further includes an auxiliary agent C, which is selected from one or more small molecule organic compounds; the small molecule organic compounds contain N-atom-containing groups that can form strong coordination interactions with metal ions; preferably, the molecular weight of the small molecule organic compounds is 40-1000 g / mol; preferably, based on 100 parts by weight of the inorganic compound solid particles, the content of the auxiliary agent C is 0.2-5 parts by weight, preferably 1-3 parts by weight.

9. The inorganic compound slurry according to claim 8, wherein, The small molecule organic compound is selected from one or more of compounds containing one nitrogen atom, compounds containing two nitrogen atoms, compounds containing three nitrogen atoms, or cyano compounds; preferably, the compound containing one nitrogen atom is selected from one or more of primary amines, secondary amines, and tertiary amines; preferably, the compound containing two nitrogen atoms is selected from one or more of ethylenediamine, pyridazine compounds, and phenanthroline compounds; preferably, the compound containing three nitrogen atoms is selected from one or more of benzotriazole and / or methylbenzotriazole; preferably, the cyano compound is selected from one or more of acetonitrile, benzonitrile, and their derivatives.

10. The inorganic compound slurry according to any one of claims 1-9, wherein, The inorganic compound slurry further includes a solvent selected from one or more of N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, methanol, ethanol, acetone, acetonitrile, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, ethylene carbonate, propylene carbonate, octane, isooctane, petroleum ether, cyclohexane, carbon tetrachloride, trichloroethylene, carbon disulfide, toluene, benzene, dichloromethane, chloroform, diethyl ether, ethyl acetate, and acetone; preferably, based on 100 parts by weight of the inorganic compound solid particles, the solvent content is 100-10000 parts by weight.

11. The application of the inorganic compound slurry as described in any one of claims 1-10 in the preparation of lithium battery cathode slurry.

12. A lithium battery positive electrode slurry, characterized in that, The lithium battery cathode slurry contains the inorganic compound slurry as described in any one of claims 1-10.

13. The lithium battery cathode slurry according to claim 12, wherein, Based on the total mass of solids in the lithium battery cathode slurry, the amount of inorganic compound slurry added is 0.1-5 wt%.

14. The lithium battery cathode slurry according to claim 12 or 13, wherein, The fineness of the lithium battery cathode slurry is no greater than 80 μm, preferably 30-70 μm; and / or, the viscosity increase of the lithium battery cathode slurry over 12 hours is no greater than 100%.

15. A lithium battery positive electrode, characterized in that, The lithium battery cathode is prepared from the cathode slurry described in any one of claims 12-14.

Images