Dispersion liquid and preparation method thereof

Abstract

The invention discloses a dispersion liquid and a preparation method thereof, the dispersion liquid comprises oxide particles, a solvent and a dispersing agent, the dispersing agent comprises substances with the following structure: in the formula, R1, R2, R3 and R4 are respectively and independently H or alkyl; r5O is an oxyalkylene group; the Q group is alkylene, a carbonyl-containing group or does not exist; the A group is a binary acid group; x, y and n are respectively selected from any integer from 1 to 130; and p is any integer from 6 to 178, preferably any integer from 6 to 124.

Description

Technical Field

[0001] This application relates to the field of battery materials, specifically to a dispersion and its preparation method. Background Technology

[0002] In the preparation of secondary batteries, the traditional method is to solve the problem of solid electrolyte slurry agglomeration by adding dispersants. The surface adsorption and steric hindrance of the dispersant prevent the solid electrolyte particles from agglomerating. However, in aqueous systems, the solid electrolyte is rich in lithium ions on its surface, which easily undergoes lithium-hydrogen exchange with water. This increases the alkalinity of the entire dispersion system, neutralizes the acidic functional groups in the dispersant, weakens the surface adsorption of the dispersant, and causes the dispersant to fail during grinding and storage. As a result, the particle size stability of the dispersion drops significantly, and the agglomerates cannot be reopened. Even with high-speed dispersion and grinding, the dispersion state before storage cannot be restored.

[0003] Currently, the solution to stabilize the solid content of solid electrolytes is to use thickeners. These thickeners, rich in hydroxyl groups, form a strong spatial network structure that prevents particle sedimentation. However, in aqueous systems, the solvent also contains numerous hydrogen bonds, leading to increased viscosity and particle agglomeration. Furthermore, solid electrolyte slurries also suffer from phase separation. This is mainly due to the intermolecular forces or hydrogen bonds between certain high-density solid electrolyte materials and the solvent being much weaker than gravity, or the solvent being squeezed out of the gaps between electrolyte particles after slow sedimentation in electrolyte slurries stored for extended periods. The appearance of phase separation indicates severe agglomeration of the slurry, making redispersibility difficult. Summary of the Invention

[0004] To address the aforementioned problems, this application provides a dispersion that solves the problem of particle agglomeration of solid electrolyte particles during grinding, while also reducing the grinding particle size.

[0005] This application provides a dispersion comprising oxide particles, a solvent, and a dispersant, wherein the dispersant comprises a substance having the following structure:

[0006]

[0007] in,

[0008] R1, R2, R3, and R4 are each independently H or alkyl groups;

[0009] R5O is an alkylene oxide;

[0010] The Q group is an alkylene group, a group containing a carbonyl group, or is absent;

[0011] Group A is a dicarboxylic acid group;

[0012] x, y, and n are each selected from any integer from 1 to 130;

[0013] p is any integer from 6 to 178, preferably any integer from 6 to 124.

[0014] Furthermore, the dicarboxylic acid group is selected from one or more of the following groups: maleic acid group, maleic anhydride group, succinic acid group, succinic anhydride group, fumaric acid group, and citrate group.

[0015] Each R5O is independently selected from oxoalkylene groups containing 2 to 18 carbon atoms; and / or

[0016] The Q group is an alkylene group or a carbonyl group containing 1 to 18 carbon atoms, preferably a methylene group or a carbonyl group.

[0017] Furthermore, the molar ratio of x to y is (2–15):1; and / or

[0018] The molar ratio of (x+y) to n is (2~18):1.

[0019] Furthermore, the weight-average molecular weight of the dispersant is 700–500,000, preferably 12,000–300,000, and most preferably 20,000–200,000.

[0020] Furthermore, the ratio of the weight-average molecular weight to the number-average molecular weight of the dispersant, Mw / Mn, is less than or equal to 1.2, preferably ≤1.1.

[0021] Furthermore, the mass fraction of the solid content in the dispersion is 40% to 85%.

[0022] Furthermore, the particle size D of the dispersion 50 The wavelength is 150-1000 nm, preferably 200-500 nm, more preferably 200-350 nm; and / or

[0023] The phase separation rate of the dispersion is ≤3%, preferably ≤2%, more preferably ≤1%; and / or

[0024] The redispersibility R of the dispersion is ≤5%, preferably ≤3%, and more preferably ≤2%.

[0025] Further, the mass ratio of the oxide particles, solvent and dispersant is 100:(17.8-165):(1-10), preferably 100:(25.5-157.5):(2-5).

[0026] Furthermore, the oxide particles have a pH value greater than 10 after being dispersed in water, preferably 11 to 14.

[0027] Furthermore, the oxide particles are selected from one of perovskite, garnet, and NASICON-structured solid electrolytes; and / or

[0028] The solvent is selected from at least one of deionized water, ethanol, ethylene glycol, and isopropanol.

[0029] Furthermore, the oxide particles are selected from Li 3x1 La 2 / 3-x1 TiO3, Li 7-x2 La3Zr 2-x2 B x2 O 12 Li 1+ x3 Zr2Si x3 P 3-x3 O 12 Or Na 1+x3 Zr2Si x3 P 3-x3 O 12 B is selected from one or more of Nb, Ta, and W, 0 <x1<0.16,0≤x2≤1,0≤x3≤5。

[0030] Furthermore, the particle size D of the oxide particles 50 The range is 0.5–1000 μm.

[0031] This application also provides a method for preparing a dispersion, comprising the following steps:

[0032] Mixing: The oxide particles, solvent, and dispersant are mixed to obtain a mixed slurry;

[0033] Grinding: The mixed slurry is ground to obtain the dispersion.

[0034] This application provides an application of a dispersion in a secondary battery, wherein the secondary battery is a lithium-ion battery or a sodium-ion battery.

[0035] The dispersion disclosed in this application solves the problem of particle agglomeration of oxide particles (solid electrolyte particles) during grinding by employing a dispersant containing carboxylic acid functional groups. This also reduces the particle size and improves grinding efficiency. The carboxylic acid groups include monocarboxylic acid groups with high hydrophilicity and dicarboxylic acid groups that provide more functional groups. The combined use of monocarboxylic acid and dicarboxylic acid groups enhances the anchoring ability of the dispersant to the surface of the oxide particles, thereby improving wettability and stability. Furthermore, the strong anchoring effect, combined with the steric hindrance of the alkoxy segments in the dispersant, allows the dispersant to fully extend in the solvent. The hydrogen bonds formed between the dispersant and the solvent prevent phase separation, thus improving redispersibility. Controlling the molecular weight distribution of the dispersant further improves the system homogeneity, anchoring solid electrolyte particles and solvent molecules, preventing phase separation, and further enhancing redispersibility. Additionally, increasing the solid content ratio in the solid electrolyte reduces the amount of free solvent, allowing the dispersant to fully bind solvent molecules. This stabilizes the system, overcoming phase separation caused by gravity during storage, ultimately achieving long-term stable storage of the slurry and easy redispersibility upon use. Attached Figure Description

[0036] Figure 1 The image shows the GPC spectrum of the dispersant prepared in Example 1 of this application.

[0037] Figure 2 The infrared spectrum is of the dispersant prepared in Example 1 of this application. Detailed Implementation

[0038] The following description provides exemplary embodiments of this application, including various details to aid understanding, and should be considered merely exemplary. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of this application. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description.

[0039] This application provides a dispersion comprising oxide particles, a solvent, and a dispersant, wherein the dispersant comprises a substance having the following structure:

[0040]

[0041] in,

[0042] R1, R2, R3, and R4 are each independently H or alkyl groups;

[0043] R5O is an oxoalkylene group.

[0044] The Q group is an alkylene group or a group containing a carbonyl group;

[0045] Group A is a dicarboxylic acid group;

[0046] x, y, and n are each selected from any integer from 1 to 130;

[0047] When y is greater than 1, the repeating unit A is either the same or different;

[0048] When n is greater than 1, repeating unit R2 is either the same or different, and repeating unit R3 is either the same or different.

[0049] Repeating unit R4 can be the same or different, and repeating unit Q can be the same or different;

[0050] p is any integer from 6 to 178, preferably any integer from 6 to 124;

[0051] Each R5O unit can be the same or different and can be independent of each other.

[0052] Furthermore, R1, R2, R3, and R4 can be the same or different.

[0053] x, y, n, and p can be tested or calculated using conventional methods. For example, the range of values ​​can be derived by inverting the molecular weight of the dispersant after synthesis based on the proportion of raw materials added during dispersant synthesis and the molecular weight of the dispersant after GPC testing.

[0054] When R1, R2, R3, and R4 are all independent alkyl groups, the alkyl group can be methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, or tert-butyl, etc.

[0055] In some implementations, R1, R2, R3, and R4 are all H or CH3.

[0056] In some embodiments, any one, two, or three of R1, R2, R3, and R4 are H, and the others are methyl groups.

[0057] Furthermore, -(R5O) p - represents a group formed by the addition polymerization of p alkyl epoxides. For example, each R5O unit can be independently represented as an alkylene oxide having 2 to 18 carbon atoms. The types of R5O units can be the same or different. Specifically, each of the p R5O units can be independently selected from one or more of the following: oxyethylidene chain, oxypropylene chain, oxybutylidene, oxypentylidene, oxyhexylidene, oxyethylidene / oxypropyleneide chain in a certain proportion, or oxyethylidene / isopropylidene oxygen chain in a certain proportion.

[0058] The number of carbon atoms in each R5O unit can be 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, or 18.

[0059] Furthermore, the Q group is an alkylene group containing 1 to 18 carbon atoms, such as methylene, ethylene, propylene, or butylene, preferably methylene.

[0060] Furthermore, the Q group is a carbonyl group or does not exist.

[0061] Furthermore, regarding group A, the dicarboxylic acid group is selected from one or more of the following: maleic acid group, maleic anhydride group, succinic acid group, succinic anhydride group, fumaric acid group, and citrate group.

[0062] Furthermore, x, y, and n can be independently 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, etc. The values ​​of x, y, and n can be different.

[0063] Furthermore, p can be 6, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, 175, or 178.

[0064] In this application, the molar ratio of x to y is (2-15):1. Specifically, the molar ratio of x to y can be 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, etc. Preferably, the molar ratio of x to y is (5-10):1.

[0065] The molar ratio of (x+y) to n is (2-18):1. Specifically, the molar ratio of (x+y) to n can be 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, etc. Preferably, the molar ratio of (x+y) to n is (5-13):1.

[0066] In this application, the weight-average molecular weight of the dispersant is 700 to 500,000, preferably 12,000 to 300,000, and even more preferably 20,000 to 200,000.

[0067] For example, the weight-average molecular weight of the dispersant can be 700, 800, 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, 10000, 11000, 12000, 13000, 14000, 15000, 16000, 17000, 18000, 19000, 20000, 21000, 220 00, 23000, 24000, 25000, 26000, 27000, 28000, 30000, 40000, 50000, 60000, 70000, 80000, 90000, 100000, 150000, 200000, 250000, 300000, 350000, 400000, 450000 or 500000.

[0068] In this application, the ratio of the weight-average molecular weight to the number-average molecular weight of the dispersant, Mw / Mn, is less than or equal to 1.2, preferably less than or equal to 1.1. For example, it can be 1, 1.01, 1.02, 1.03, 1.04, 1.05, 1.06, 1.07, 1.08, 1.09, 1.1, 1.11, 1.12, 1.13, 1.14, 1.15, 1.16, 1.17, 1.18, 1.19, or 1.2.

[0069] In this paper, GPC was used to test the weight-average molecular weight and number-average molecular weight of polymers, and the polydispersity index α was used to characterize the molecular weight distribution of the dispersant, i.e., polydispersity index α = Mw / Mn.

[0070] In this application, solid content refers to the ratio of the total mass of oxide particles to the total mass of the dispersion. In the dispersion, the solid content is 40% to 85%, and the mass fraction of the solid content can be 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, etc.

[0071] In this paper, the mass fraction of solids in the dispersion was tested using the drying method.

[0072] In this application, the particle size D of the dispersion 50The wavelength range is 150–1000 nm, preferably 200–500 nm, and more preferably 200–350 nm. For example, it can be 150 nm, 170 nm, 180 nm, 190 nm, 200 nm, 210 nm, 220 nm, 230 nm, 240 nm, 250 nm, 260 nm, 270 nm, 280 nm, 290 nm, 300 nm, 310 nm, 320 nm, 330 nm, 340 nm, 3 50nm, 360nm, 370nm, 380nm, 390nm, 400nm, 410nm, 420nm, 430nm, 440nm, 450nm, 460nm, 470nm, 480nm, 490nm, 500nm, 550nm, 600nm, 6500nm, 700nm, 750nm, 800nm, 850nm, 900nm, 950nm, 1000nm, etc.

[0073] In this article, D 50 D can be obtained through laser particle size analyzer testing. 50 Particle size refers to the particle size that corresponds to the cumulative particle size distribution percentage of a sample reaching 50%.

[0074] In this application, the viscosity of the dispersion is 1000-10000 Pa·s.

[0075] In this application, the phase separation rate of the dispersion is ≤3%, preferably ≤2%, and more preferably ≤1%; for example, it can be 3%, 2.9%, 2.8%, 2.7%, 2.6%, 2.5%, 2.4%, 2.3%, 2.2%, 2.1%, 2.0%, 1.9%, 1.8%, 1.7%, 1.6%, 1.5%, 1.4%, 1.3%, 1.2%, 1.1%, 1%, 0.9%, 0.8%, 0.7%, 0.6%, 0.5%, 0.4%, 0.3%, 0.2%, 0.1%, etc.

[0076] In this paper, the test procedure for the phase separation rate of the dispersion is as follows:

[0077] Step 1: Take a sample of the dispersion and record the initial solid content w0.

[0078] Step 2: Take 1L of dispersion into a 2L wide-mouth container, seal the container and let it stand for 60 days. After 60 days, take 2mL of dispersion from the liquid surface in the wide-mouth container and test the solid content, which is recorded as the upper solid content value w1 of the dispersion.

[0079] Step 3: Measure the phase separation rate S of the dispersion by the deviation between the upper solid content value w1 and the initial solid content value w0. S = |w1-w0| / w0×100%; the smaller the value of S, the more stable the slurry.

[0080] In this application, the redispersibility R of the dispersion is ≤5%, preferably ≤3%, more preferably ≤2%; for example, it can be 5%, 4.8%, 4.5%, 4.2%, 4%, 3.8%, 3.5%, 3.2%, 3%, 2.9%, 2.8%, 2.7%, 2.6%, 2.5%, 2.4%, 2.3%, 2.2%, 2.1%, 2.0%, 1.9%, 1.8%, 1.7%, 1.6%, 1.5%, 1.4%, 1.3%, 1.2%, 1.1%, 1%, etc.

[0081] In this paper, a laser particle size analyzer was used to test the particle size D of the dispersion. 50 The solvent used is the same as that used in the dispersion. The redispersibility test procedure is as follows:

[0082] Step 1: Take a sample of the dispersion and record its initial average particle size D. 50-0 .

[0083] Step 2: Take 1L of the dispersion into a 2L wide-mouth container, seal the container, and let it stand for 60 days. After 60 days, redisperse the dispersion and test the particle size, recording it as the redispersed particle size D. 50-1 The dispersion method involves using a single-blade mechanical stirrer with a blade radius of 5 cm, a rotation speed of 250 rpm, a linear velocity of 1.3 m / s, and stirring for 30 minutes.

[0084] Step 3: Utilize the redispersible particle size D 50-1 With initial granularity D 50-0 Deviation measures the redispersibility R of a dispersion. R = |D| 50-1 -D 50-0 | / D 50-0 ×100%, the smaller the value of R, the less agglomerate the dispersion is, and the easier it is to disperse.

[0085] In this application, from the perspective of the dispersant's effect on improving wettability and stability, the mass ratio of oxide particles, solvent, and dispersant is 100:(17.8-165):(1-10), preferably 100:

[0086] (25.5~157.5): (2~5), if the amount of dispersant added is too small, the preset effect cannot be achieved; if the amount added is too large, the dispersion effect will not increase, but will decrease due to self-aggregation.

[0087] Specifically, in the dispersion, the mass ratio of oxide particles to solvent can be 100:17.8, 100:20, 100:25, 100:30, 100:35, 100:40, 100:45, 100:50, 100:55, 100:60, 100:65, 100:70, 100:75, 100:80, 100:85, 100:90, 100:95, 100:100, 100:110, 100:120, 100:130, 100:140, 100:150, 100:160, 100:165, etc.

[0088] Specifically, in the dispersion, the mass ratio of oxide particles to dispersant can be 100:1, 100:1.5, 100:2, 100:2.5, 100:3, 100:3.5, 100:4, 100:4.5, 100:5, 100:5.5, 100:6, 100:6.5, 100:7, 100:7.5, 100:8, 100:8.5, 100:9, 100:9.5, 100:10, etc.

[0089] In this application, the oxide particles have a pH value greater than 10 after being dispersed in water.

[0090] In some embodiments, the oxide particles dispersed in water have a pH value of 11–14. Oxide particles meeting this pH range can be used to prepare a stable dispersion that meets the requirements of this application.

[0091] The pH value of oxide particles after dispersion in water is determined by dispersing the oxide particles in water to prepare a 10% solution and then testing its pH value.

[0092] Furthermore, the oxide particles are selected from one of the following: perovskite, garnet, and NASICON structured solid electrolytes.

[0093] Furthermore, the oxide particles are selected from Li 3x1 La 2 / 3-x1 TiO3, Li 7-x2 La3Zr 2-x2 B x2 O 12 Li 1+ x3 Zr2Si x3 P 3-x3 O 12 Or Na 1+x3 Zr2Si x3 P 3-x3 O 12B is selected from one or more of Nb, Ta, and W, 0 <x1<0.16,0≤x2≤1,0≤x3≤5。

[0094] Furthermore, the oxide particles are Li 0.33 La 0.56 TiO3, LLZO, LZSP (Li3Zr2Si2PO 12 ) or NZSP(Na3Zr2Si2PO 12 ).

[0095] Furthermore, the particle size D of the oxide particles 50 The range is from 0.5 to 1000 μm, for example, it can be 0.5 μm, 1 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm, 550 μm, 600 μm, 650 μm, 700 μm, 750 μm, 800 μm, 850 μm, 900 μm, 950 μm, 1000 μm, etc.

[0096] The dispersion also contains a defoamer, which acts to disrupt and inhibit the formation and stability of bubbles, thereby reducing or eliminating the presence of foam; it is selected from at least one of polyether defoamers, silicone defoamers, polyether-modified silicone defoamers, self-emulsifying defoamers, and polysiloxane defoamers.

[0097] The defoamer is added at a mass of 0-2% of the dispersion, preferably 0.5-2%, for example: 0.1%, 0.3%, 0.5%, 0.7%, 0.9%, 1%, 1.2%, 1.4%, 1.6%, 1.8%, 2%.

[0098] In this application, the solvent is selected from at least one of deionized water, ethanol, ethylene glycol, and isopropanol.

[0099] In some embodiments, the dispersant in the dispersion has the following structure:

[0100]

[0101] This application also provides a method for preparing a dispersant, comprising the following steps:

[0102] Step 1: Dissolve the polyether polyol containing double bonds and the raw material containing A groups in deionized water to obtain a mixed solution;

[0103] Step 2: Heat the mixed solution to T1, and then add acrylic monomers, initiators and chain transfer agents dropwise.

[0104] Step 3: After the addition is complete, keep the reaction at a certain temperature for a certain period of time, cool it down to room temperature, and then adjust it to neutral with alkali solution to obtain the dispersant.

[0105] In step 1, the polyether polyol containing double bonds is selected from one or more of allyl alcohol polyether, methyl allyl polyether, isopentenyl alcohol polyether, vinyl glycol ether, polyethylene glycol monomethyl ether methacrylate, and polyethylene glycol monomethyl ether acrylate.

[0106] The number-average molecular weight Mn of the polyether polyol containing double bonds can be 1000-6000, preferably 1200-4500, and the prepared dispersion has strong stability and is not easy to separate into phases.

[0107] The raw materials containing the A group are one or more of maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, fumaric acid, or citraconic acid.

[0108] In the mixed solution, the content of polyether polyol containing double bonds is 24.0 to 1275.0 parts by weight, the content of raw material containing A group is 9.8 to 14.0 parts by weight, and the content of deionized water is 40.0 to 1700.0 parts by weight.

[0109] Specifically, the content of polyether polyols containing double bonds can be 24.0 parts by weight, 25 parts by weight, 30 parts by weight, 40 parts by weight, 50 parts by weight, 60 parts by weight, 70 parts by weight, 80 parts by weight, 90 parts by weight, 100 parts by weight, 110 parts by weight, 120 parts by weight, 130 parts by weight, 140 parts by weight, 150 parts by weight, 160 parts by weight, 170 parts by weight, 180 parts by weight, 190 parts by weight, 2... 00 parts by weight, 250 parts by weight, 300 parts by weight, 350 parts by weight, 400 parts by weight, 450 parts by weight, 500 parts by weight, 550 parts by weight, 600 parts by weight, 650 parts by weight, 700 parts by weight, 750 parts by weight, 800 parts by weight, 850 parts by weight, 900 parts by weight, 950 parts by weight, 1000 parts by weight, 1100 parts by weight, 1200 parts by weight, 1275.0 parts by weight, etc.

[0110] The content of raw materials containing the A group can be 9.8 parts by weight, 1 part by weight, 1.5 parts by weight, 2 parts by weight, 2.5 parts by weight, 3 parts by weight, 3.5 parts by weight, 4 parts by weight, 4.5 parts by weight, 5 parts by weight, 5.5 parts by weight, 6 parts by weight, 6.5 parts by weight, 7 parts by weight, 7.5 parts by weight, 8 parts by weight, 8.5 parts by weight, 9 parts by weight, 9.5 parts by weight, 10 parts by weight, 10.5 parts by weight, 11 parts by weight, 11.5 parts by weight, 12 parts by weight, 12.5 parts by weight, 13 parts by weight, 13.5 parts by weight, 14 parts by weight, etc.

[0111] The deionized water content is 40.0 parts by weight, 50 parts by weight, 100 parts by weight, 200 parts by weight, 300 parts by weight, 400 parts by weight, 500 parts by weight, 600 parts by weight, 700 parts by weight, 800 parts by weight, 900 parts by weight, 1000 parts by weight, 1100 parts by weight, 1200 parts by weight, 1300 parts by weight, 1400 parts by weight, 1500 parts by weight, 1600 parts by weight, 1700 parts by weight, etc.

[0112] In step two, the acrylic monomer is selected from one or more alkyl-containing acrylates such as acrylic acid and methacrylic acid.

[0113] The initiator may be selected from one or more of hydrogen peroxide, ammonium persulfate, sodium persulfate, potassium persulfate, and azobisisobutyramidine hydrochloride.

[0114] The chain transfer agent may be selected from one or more of the following: mercaptoethanol, thioglycerol, mercaptoacetic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thiohydroxymalic acid, octyl mercaptoacetate, octyl 3-mercaptopropionate, 2-mercaptoethanesulfonic acid, n-dodecyl mercaptan, octyl mercaptan, butyl mercaptoacetate, isopropanol, and 2-mercapto-S-thiobenzoylacetic acid.

[0115] T1 can be 40 to 100°C, preferably 60 to 90°C. For example, it can be 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, etc.

[0116] The dripping time can be 1–8 hours, preferably 2–6 hours;

[0117] The content of acrylic monomers is 14.4 to 130.0 parts by weight, the content of chain transfer agent is 0.2 to 5.6 parts by weight, and the content of initiator is 0.9 to 27.9 parts by weight.

[0118] Furthermore, the content of acrylic monomers can be 14.4 parts by weight, 15 parts by weight, 20 parts by weight, 25 parts by weight, 30 parts by weight, 35 parts by weight, 40 parts by weight, 45 parts by weight, 50 parts by weight, 55 parts by weight, 60 parts by weight, 65 parts by weight, 70 parts by weight, 75 parts by weight, 80 parts by weight, 85 parts by weight, 90 parts by weight, 95 parts by weight, 100 parts by weight, 105 parts by weight, 110 parts by weight, 115 parts by weight, 120 parts by weight, 125 parts by weight, 130.0 parts by weight, etc.

[0119] The content of the chain transfer agent can be 0.2 parts by weight, 0.5 parts by weight, 1 part by weight, 1.5 parts by weight, 2 parts by weight, 2.5 parts by weight, 3 parts by weight, 3.5 parts by weight, 4 parts by weight, 4.5 parts by weight, 5 parts by weight, 5.5 parts by weight, 5.6 parts by weight, etc.

[0120] The initiator content can be 0.9 parts by weight, 1 part by weight, 2 parts by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight, 7 parts by weight, 8 parts by weight, 9 parts by weight, 10 parts by weight, 11 parts by weight, 12 parts by weight, 13 parts by weight, 14 parts by weight, 15 parts by weight, 16 parts by weight, 17 parts by weight, 18 parts by weight, 19 parts by weight, 20 parts by weight, 21 parts by weight, 22 parts by weight, 23 parts by weight, 24 parts by weight, 25 parts by weight, 26 parts by weight, 27 parts by weight, 27.9 parts by weight, etc.

[0121] In step 3, the alkaline solution may be selected from one or more of NaOH, KOH and LiOH.

[0122] The reaction time can be 1 to 12 hours, preferably 2 to 7 hours, for example, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, etc.

[0123] Furthermore, the method for preparing the dispersant is as follows:

[0124] Step 1: Add 24.0–1275.0 parts by weight of polyether polyol containing double bonds, 9.8–14.0 parts by weight of raw material containing A groups, and 40.0–1700.0 parts by weight of deionized water to the reactor. Under nitrogen protection, cool and circulate the mixture, raise the temperature to 60–90°C, and mechanically stir to ensure complete dissolution.

[0125] Step 2.1: Add 14.4 to 130.0 parts by weight of acrylic monomer, 0.2 to 5.6 parts by weight of chain transfer agent and 20 to 250 parts by weight of deionized water to drop tank 1 to obtain mixture 1.

[0126] Step 2.2: Add 0.9 to 27.9 parts by weight of initiator and 10 to 200 parts by weight of deionized water to the dropping tank 2 to obtain mixture 2.

[0127] Step 3: Heat the reaction system to 60-90℃, and simultaneously add the mixture from dropping tank 1 and dropping tank 2 into the reactor over 2-5 hours. Keep the reaction at this temperature for 2-5 hours, and then cool it to room temperature. Adjust the pH to neutral using an alkaline solution to obtain the dispersant.

[0128] This application also provides a method for preparing a dispersion, comprising the following steps:

[0129] Mixing: The oxide particles, solvent, and dispersant are mixed to obtain a mixed slurry;

[0130] Grinding: The mixed slurry is ground to obtain the dispersion.

[0131] During the grinding process, the grinding linear speed is 1 to 20 m / s.

[0132] The dispersion prepared by the preparation method is the aforementioned dispersion, and the parameters of the dispersion can be referred to the above description.

[0133] This application also provides the application of the dispersion in secondary batteries, wherein the secondary battery is a lithium-ion battery or a sodium-ion battery.

[0134] Implementation Examples and Test Sections

[0135] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0136] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0137] I. Implementation Examples

[0138] Example 1

[0139] 1) Preparation of dispersant a

[0140] Step 1: Add 375.0 parts by weight of isopentenyl alcohol polyether TPEG (Mn=3000, EO / PO=3:1), 9.8 parts by weight of maleic anhydride, and 500 parts by weight of deionized water to the reactor. Under nitrogen protection, cool and circulate the solution, and mechanically stir to ensure complete dissolution.

[0141] Step 2: Add 57.7 parts by weight of acrylic acid, 1.8 parts by weight of mercaptopropionic acid and 100 parts by weight of deionized water to the dropping tank 1 to obtain mixture 1.

[0142] Step 2.2: Add 8.9 parts by weight of ammonium persulfate and 77 parts by weight of deionized water to the dropping tank 2 to obtain mixture 2.

[0143] Step 3: Heat the reaction system to 80℃, and simultaneously add the mixture from dropping tank 1 and dropping tank 2 to the reaction system over 3 hours. Maintain the temperature for 3 hours, then cool to room temperature and adjust the pH to approximately 7.0 using NaOH. This yields dispersant a. The GPC test results for this dispersant are: weight-average molecular weight Mw = 23612, number-average molecular weight Mn = 21954, Mw / Mn = 1.07, where x / y = 8 and (x+y) / n = 7.2.

[0144] The GPC spectrum of the dispersant is as follows: Figure 1 The infrared spectrum of the dispersant is as follows: Figure 2 .

[0145] (ii) Preparation of dispersion

[0146] Take 100g of oxide particles (Li 0.3 La 0.56 TiO3), 102g of deionized water and 2g of dry dispersant were mixed to obtain a mixed slurry.

[0147] The mixed slurry was ground at a linear speed of 20 m / s for 15 h to obtain a dispersion with a particle size of 284 nm and a viscosity of 2079 mPa·s. At a constant grinding rate, increasing the grinding time can reduce the particle size of the dispersion, increase the slurry viscosity, and improve solids stability, while still satisfying the requirements for redispersibility and preventing phase separation.

[0148] The only difference between the dispersion in Example 2 and the dispersion in Example 1 is that the grinding time is shorter, the particle size of the dispersion is 354 nm, and the viscosity of the dispersion is 1111 mPa·s.

[0149] The only difference between the dispersions in Examples 3 and 4 and those in Example 2 is that the mass ratio of the polymeric monomer to the initiator is different. The mass of the polymeric monomer is the total mass of isopentenyl alcohol polyether TPEG, maleic anhydride, and acrylic acid, which is the same as the total mass of the polymeric monomer in Example 2. Dispersants b and c were prepared, and the parameters of the dispersions obtained through the dispersant preparation steps are shown in Table 1.

[0150] The only difference between Examples 5 and 6 and Example 2 is that the mass ratio of dispersant to oxide particles in the dispersion is different. The parameters of the dispersion obtained by the dispersant preparation step are shown in Table 2.

[0151] The dispersion in Example 7 differs from that in Example 2 only in that the electrolyte used is Li7La3Zr2O. 12The types of polyether polyols containing double bonds are different. In Example 7, the molar ratio of polyether polyol containing double bonds to maleic anhydride and acrylic acid is the same as that in Example 2. Dispersant d is prepared. The parameters of the dispersion obtained by the dispersant preparation step are shown in Table 3.

[0152] The dispersion in Example 8 differs from that in Example 2 only in that the electrolyte used is Na3Zr2Si2PO4. 12 The types of monobasic and dibasic acids differ. In Example 8, the molar ratio of the polyether polyol containing double bonds to the monobasic and dibasic acids is the same as that in Example 2, thus dispersant e is prepared.

[0153] (ii) Preparation of dispersion

[0154] Take 100g of oxide particles (Li 0.3 La 0.56 TiO3), 102g of deionized water, 2g of dispersant and 2g of polyether-modified silicone defoamer were mixed to obtain a mixed slurry.

[0155] The mixed slurry was ground at a linear speed of 20 m / s for 15 h to obtain a dispersion. The parameters of the dispersion are shown in Table 3.

[0156] The only difference between the dispersion of Comparative Example 1 and Example 2 is that no dispersant was added in Comparative Example 1. The parameters of the final dispersion are shown in Table 4.

[0157] The only difference between the dispersion of Comparative Example 2 and Example 2 is that the dispersant f was prepared without the addition of the polyether polyol containing double bonds. The parameters of the final dispersion are shown in Table 3.

[0158] The only difference between the dispersions of Comparative Examples 3 and 4 and those of Example 2 is that the mass ratio of the polymeric monomer to the initiator is different. The mass of the polymeric monomer is the total mass of isopentenyl alcohol polyether TPEG, maleic anhydride, and acrylic acid, which is the same as the total mass of the polymeric monomer in Example 2. The dispersant g and h were prepared, and the parameters of the final prepared dispersion are shown in Table 1.

[0159] The only difference between the dispersion of Comparative Example 5 and Example 2 is that the amount of deionized water added is different, resulting in different solid content in the dispersion. The parameters of the final dispersion are shown in Table 4.

[0160] II. Testing Section

[0161] 1. Method for testing the phase separation rate of dispersions: The solid content of the dispersion is tested using the drying method. The steps for testing the phase separation rate are as follows:

[0162] Take a sample of the prepared dispersion and test its solid content; record this as the initial solid content.

[0163] Take 1L of dispersion into a 2L wide-mouth container, seal the container and let it stand for 60 days. After 60 days, take 2mL of dispersion from the liquid surface in the wide-mouth container and test the solid content, which is recorded as the upper solid content value w1 of the dispersion.

[0164] The dispersion fraction S is measured by the deviation between the upper solid content value w1 and the initial solid content value w0. S = |w1-w0| / w0×100%; the smaller the value of S, the more stable the slurry.

[0165] 2. Dispersion redispersibility test method: The particle size D of the dispersion is measured using a laser particle size analyzer. 50 The solvent used is the same as the solvent in the dispersant. The redispersibility test procedure is as follows:

[0166] Test the particle size of the prepared dispersion and record it as the initial average particle size D. 50-0 .

[0167] Take 1 L of the dispersion and place it in a 2 L wide-mouth container. Seal the container and let it stand for 60 days. After 60 days, redisperse the dispersion and test the particle size, recording it as the redispersed particle size D. 50-1 The dispersion method involves using a single-blade mechanical stirrer with a blade radius of 5 cm, a rotation speed of 250 rpm, a linear velocity of 1.3 m / s, and stirring for 30 minutes.

[0168] Utilizing the redispersed particle size D 50-1 With initial granularity D 50-0 Deviation measures the redispersibility R of a dispersion. R = |D| 50-1 -D 50-0 | / D 50-0 ×100%, the smaller the value of R, the less agglomerate the dispersion is, and the easier it is to disperse.

[0169] 3. Molecular weight distribution test method: The weight-average molecular weight and number-average molecular weight of the dispersant are tested using GPC. The polydispersity index α is used to characterize the molecular weight distribution of the dispersant, that is, polydispersity index α = weight-average molecular weight / number-average molecular weight = Mw / Mn.

[0170] 4. Method for measuring the viscosity of the dispersion: Take 50 mL of slurry into a centrifuge tube for testing. Use a 64# rotor on a rotational viscometer at 60 rpm. Rotate the rotor in the test sample for 2 minutes, with a data acquisition time of 1 minute. Record the viscosity value after the test.

[0171] Table 1 shows the effect of the mass ratio of monomer to initiator on the dispersion.

[0172]

[0173] As shown in the table above, changing the amounts of raw materials and initiators affects the molecular weight distribution width of the dispersant and the steric hindrance of the polyether fraction, thus leading to dispersion and sedimentation stability issues in the oxide particles. A wider molecular weight distribution can cause coarsening of the solid electrolyte and stratification of the dispersant slurry.

[0174] Table 2 shows the effect of the mass ratio of dispersant to oxide particles on the dispersion.

[0175]

[0176] Table 3 shows the effect of the type of polyether polyol with double bonds, monobasic acid, and dibasic acid on the dispersion.

[0177]

[0178]

[0179] As shown in the table above, TPEG and VPEG are used for polyether polyols, acrylic acid and methacrylic acid are used for monocarboxylic acids, and maleic anhydride and coacinic acid are used for dicarboxylic acids. All of these can prepare dispersants that meet the requirements of this application. In addition, an antifoaming agent was added in Example 8, which can reduce the permissibility of bubbles and thus prepare a dispersion with more stable performance.

[0180] Table 4 shows the effect of solid content on dispersion.

[0181]

[0182] As shown in the table above, when the solid content in the dispersion is low, or when no dispersant is added to the dispersion, it will lead to a phenomenon of coarsening of the particle size.

[0183] Although the embodiments of this application have been described above, this application is not limited to the specific embodiments and application fields described above. The specific embodiments described above are merely illustrative and instructive, and not restrictive. Those skilled in the art, based on the guidance of this specification and without departing from the scope of protection of the claims of this application, can make many other forms, all of which are within the scope of protection of this application.

Claims

1. A dispersion, wherein, The dispersant comprises an oxide particle, a solvent, and a dispersant comprising a substance having the following structure: wherein, R1, R2, R3, R4 are independently H or alkyl; R5O is oxyalkylene; Q is alkylene, a group containing a carbonyl group, or is absent; A is a dibasic acid group; x, y, n are independently selected from any integer from 1 to 130; p is any integer from 6 to 178, preferably any integer from 6 to 124.

2. The dispersion of claim 1, wherein, The dibasic acid group is selected from one or more of a maleic acid group, a maleic anhydride group, a succinic acid group, a succinic anhydride group, a fumaric acid group, and a citraconic acid group; and / or each R5O is independently selected from oxyalkylene containing 2 to 18 carbon atoms; and / or Q is alkylene containing 1 to 18 carbon atoms or a carbonyl group, preferably methylene or a carbonyl group.

3. The dispersion according to claim 1, wherein, the molar ratio of x to y is (2-15):1; and / or the molar ratio of (x+y) to n is (2-18):

1.

4. The dispersion of claim 1, wherein, The dispersant has a weight average molecular weight of 700 to 500,000, preferably 12,000 to 300,000, most preferably 20,000 to 200,000.

5. The dispersion of claim 1, wherein, The dispersant has a ratio of weight average molecular weight to number average molecular weight Mw / Mn of less than or equal to 1.2, preferably ≤1.

1.

6. The dispersion of claim 1, wherein, In the dispersion, the solid content has a mass fraction of 20 to 85%, preferably 40 to 85%.

7. The dispersion of claim 1, wherein, Particle size D of the dispersion 50 is 150 to 1000 nm, preferably 200 to 500 nm; and / or The dispersion has a phase separation rate of ≤3%, preferably ≤2%, more preferably ≤1%; and / or The dispersion has a re-dispersibility R of ≤5%, preferably ≤3%, more preferably ≤2%.

8. The dispersion of claim 1, wherein, The oxide particle, the solvent, and the dispersant have a mass ratio of 100:(17.8-440):(1-10), preferably 100:(17.8-165):(1-10), more preferably 100:(25.5-157.5):(2-5).

9. The dispersion of claim 1, wherein, The oxide particle has a pH value of greater than 10, preferably 11 to 14, after being dispersed in water.

10. The dispersion according to claim 9, wherein the oxide particle is selected from one of perovskite, garnet, and a solid-state electrolyte of NASICON structure; and / or The solvent is selected from at least one of deionized water, ethanol, ethylene glycol, and isopropyl alcohol; and / or The dispersion further comprises an antifoaming agent.

11. The dispersion of claim 1, the oxide particles being selected from Li 3x1 La 2 / 3-x1 TiO3, Li 7-x2 La3Zr 2- x2 B x2 O 12 , Li 1+x3 Zr2Si x3 P 3-x3 O 12 or Na 1+x3 Zr2Si x3 P 3-x3 O 12 , B is selected from one or more of Nb, Ta and W, 0 < x1 < 0.16, 0 < x2 < 1, 0 < x3 < 5.

12. The dispersion of claim 1, wherein, The particle size D of the oxide particles 50 0.5–1000 μm; and / or The antifoaming agent is added in an amount of 0 to 2 wt%, preferably 0.5-2 wt%, based on the total mass of the dispersion.

13. A process for the preparation of a dispersion as claimed in any one of claims 1 to 12 wherein, The method comprises the following steps: mixing: mixing the oxide particle, the solvent, and the dispersant to obtain a mixed slurry; grinding: grinding the mixed slurry to obtain the dispersion.

14. Use of the dispersion according to any one of claims 1-12 in a secondary battery, which is a lithium ion battery or a sodium ion battery.

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