Solid oxide particle dispersion with stable sedimentation

Abstract

The invention relates to the technical field of lithium ion batteries, in particular to solid oxide particle dispersion liquid, application of the solid oxide particle dispersion liquid and a lithium ion secondary battery. The dispersion liquid comprises solid oxide particles, an additive and a solvent, wherein the additive is selected from at least one of structures as shown in formulas S1-S17; wherein R1-R9 are respectively and independently selected from H, substituted or unsubstituted C1-C6 alkyl and an alkoxy chain, and at least one of R1-R9 is selected from the alkoxy chain; and n1-n6 are respectively and independently selected from integers of 1-6. The dispersion liquid adopts the additive with a specific structure, so that the dispersity, the stability and the consistency of the dispersion liquid are effectively improved; meanwhile, the additive stably exists in the battery or is evaporated, so that adverse effects on the battery are avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium ion batteries, in particular to a solid oxide particle dispersion liquid, application of the solid oxide particle dispersion liquid and a lithium ion secondary battery. BACKGROUND

[0002] The solid oxide particles are generally synthesized by a high-temperature solid-phase method, which is simple in process and low in cost, and has realized industrial production. However, the solid oxide particles synthesized by the high-temperature solid-phase method are generally micron-sized large particles or blocks, which are difficult to be directly applied in batteries and need to be processed into solid electrolyte slurry through nanocrystallization treatment, and then be compounded with other battery materials to improve uniformity and reduce interface problems. However, the solid electrolyte slurry still has problems of agglomeration, sedimentation and unstable system, which affect actual production and use, and delay the performance of the solid electrolyte.

[0003] The traditional method for solving the stability problem of the slurry is to process the solid electrolyte into high-viscosity slurry to prevent sedimentation, and to use dispersants and thickeners to improve the dispersibility and viscosity of the slurry. However, most of the additives will be soluble in the electrolyte, and even react, which leads to incompatibility with the electrolyte when producing semi-solid or quasi-solid batteries, and reduces the performance of the battery. If no additives are used, but the solid content of the slurry is directly increased to improve the stability of the solid content, the particle size stability of the slurry will also decrease, because after reducing the proportion of the solvent, the number of particles in the unit volume is more and the distance between the particles is closer, and the particles are more likely to agglomerate.

[0004] CN114512711A discloses a solid content stable inorganic oxide solid electrolyte nanodispersion liquid for batteries, which controls the solid content of the dispersion liquid to be 40-85wt% by adding an ether dispersant with a special structure, and obtains a dispersion liquid with high stability, which can reduce the requirements and cost during preparation, storage and transportation. However, the ether dispersant is not only miscible with organic solvents, but also miscible with electrolytes. If this solid electrolyte slurry is added to a hybrid solid-liquid battery, the dispersant will not be removed with the electrode baking, but will be dissolved in the electrolyte after the battery is injected with liquid, which will adversely affect the battery, and therefore is not suitable for use in the field of hybrid solid-liquid batteries. Therefore, how to improve the dispersibility, stability and consistency of the solid electrolyte slurry, and how to make the dispersant have no adverse effect on the battery, are the keys to solving the application problems of the solid electrolyte. SUMMARY

[0005] The present application aims to overcome the above technical problems, and provides a solid oxide particle dispersion liquid and application and a lithium ion secondary battery. The dispersion liquid uses an additive with a specific structure, which not only effectively improves the dispersibility, stability and consistency of the dispersion liquid, but also makes the additive insoluble in the electrolyte in the battery and stably exist, without adversely affecting the battery.

[0006] To achieve the above objectives, the first aspect of the present invention provides a solid oxide particle dispersion comprising: solid oxide particles, an additive, and a solvent, wherein the additive is selected from at least one of the structures shown in formulas S1-S17.

[0007]

[0008]

[0009] R1-R9 are each independently selected from H, substituted or unsubstituted C1-C6 alkyl, alkoxy chains, and at least one of R1-R9 is selected from an alkoxy chain; n1-n6 are each independently selected from integers 1-6.

[0010] In this invention, unless otherwise specified, the solid oxide particle dispersion is simply referred to as dispersion.

[0011] In this invention, unless otherwise specified, the high consistency of the dispersion means that the solid oxide particles in the dispersion are uniform and there is no obvious agglomeration; and the solid oxide particles in the dispersion are well dispersed and uniformly dispersed.

[0012] Preferably, in formulas S1-S17, when any two of R1-R9 are connected to the same N, at least one is selected from an alkoxy chain.

[0013] Preferably, the general formula of the alkoxy chain is: Among them, R a and R b Selected from C2-C respectively 18 Alkylene, m1 and m2 are selected from integers from 0 to 50, and m1 and m2 are not both 0, X is a capped group or an uncapped group.

[0014] The second aspect of the present invention provides an application of the dispersion provided in the first aspect in positive and negative electrode mixing, membrane coating, electrode surface coating, and organic / inorganic composite solid electrolytes.

[0015] A third aspect of the present invention provides a lithium-ion secondary battery, wherein the lithium-ion secondary battery contains the dispersion provided in the first aspect.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] (1) The additive provided by the present invention has an adsorption effect on the surface of solid oxide particles (e.g., solid electrolyte particles) by the amino part in the main chain, and the alkoxy branch structure can play a good steric hindrance role. The two work together to stabilize the solid oxide particles.

[0018] (2) The additive provided by the present invention uses uncapped end groups, such as hydroxyl groups, which reduces the solubility of the additive in the electrolyte and is applicable to mixed solid-liquid lithium-ion batteries, preventing battery failure caused by electrolyte dissolution of the additive; the branch uses capped end groups, such as phosphate ester groups, isocyanate groups, etc., which have an affinity with the dispersed solvent, further improving the dispersion effect of the dispersion liquid.

[0019] (3) The dispersion provided by the present invention can improve stability by increasing the solid content and avoid sedimentation of electrolyte particles after placement. On the other hand, it can improve the dispersibility of particles in solvent by dispersant, reduce particle agglomeration, maintain particle size stability, improve grinding efficiency, reduce grinding particle size, and improve the uniformity of dispersion. By adjusting R1-R9 in the dispersant, it is more conducive to the dispersibility, stability and consistency of dispersion.

[0020] (4) The dispersion provided by the present invention has good rheological properties and is easier to process; at the same time, the preparation method of the dispersion simplifies the process flow and facilitates industrial production; at the same time, the dispersion provided by the present invention can effectively improve the electrochemical performance of lithium-ion secondary batteries, especially the rate performance. Detailed Implementation

[0021] 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.

[0022] The first aspect of the present invention provides a solid oxide particle dispersion, the dispersion comprising: solid oxide particles, additives and solvent;

[0023] The additive is selected from at least one of the structures shown in formulas S1-S17;

[0024]

[0025]

[0026]

[0027] R1-R9 are each independently selected from H, substituted or unsubstituted C1-C6 alkyl, alkoxy chains, and at least one of R1-R9 is selected from an alkoxy chain; n1-n6 are each independently selected from integers 1-6.

[0028] In this invention, unless otherwise specified, substituted or unsubstituted C1-C6 alkyl groups include not only substituted C1-C6 alkyl groups but also unsubstituted C1-C6 alkyl groups.

[0029] In this invention, unless otherwise specified, the substituted groups include, but are not limited to, halogens and C1-C3 alkyl groups.

[0030] In some embodiments of the present invention, preferably, n1-n6 are each independently selected from integers 1-6; more preferably, n1-n6 are each independently selected from integers 1-5; more preferably, n1-n6 are each independently selected from integers 2-4.

[0031] In this invention, the additive having the structure shown in formulas S1-S17 improves the dispersibility and stability of the dispersion through the strong anchoring adsorption between the polyamino structure in the additive and the solid oxide particles; at the same time, by further limiting at least one of R1-R9 to an alkoxy chain, the additive has a good steric hindrance effect, which further improves the dispersibility and stability of the dispersion.

[0032] In some embodiments of the present invention, preferably, when any two of R1-R9 in formulas S1-S17 are connected to the same N, at least one is selected from an alkoxy chain; more preferably, when any two of R1-R9 in formulas S1-S17 are connected to the same N, they are all selected from an alkoxy chain.

[0033] In this invention, by controlling at least one group connected to the same N in S1-S17 to be selected from an alkoxy chain, the additive has good steric hindrance. Combined with the polyamino structure, the two work synergistically to more effectively improve the dispersibility and stability of the dispersion.

[0034] The alkoxy chain connected to N has a capping group, which is selected from at least one of hydrogen, phosphate ester and isocyanate groups, preferably selected from phosphate ester and / or isocyanate groups.

[0035] In some embodiments of the present invention, preferably, the general formula of the alkoxy chain is: Among them, R a and R b Selected from C2-C respectively 18 Alkylene, m1 and m2 are selected from integers from 0 to 50, and m1 and m2 are not both 0, X is a capped group or an uncapped group.

[0036] In this invention, unless otherwise specified, the above... In the middle, R a O and R b O represents a group formed by the addition polymerization of multiple epoxide alkanes, i.e., Ra O or R b O represents alkeneoxy groups having 2-18 carbon atoms.

[0037] In some embodiments of the present invention, preferably, in formula I, R a and R b Selected from C2-C respectively 10 Alkylene, preferably C2-C6 alkylene, more preferably C2-C4 alkylene.

[0038] In some embodiments of the present invention, preferably, m1 and m2 are selected from integers from 2 to 10.

[0039] In this invention, unless otherwise specified, the alkoxy chain may be selected from either a capped group or an uncapped group. Preferably, X is selected from at least one of hydrogen, phosphate ester, and isocyanate groups, and more preferably from phosphate ester and / or isocyanate groups.

[0040] In some embodiments of the present invention, more preferably, the phosphate ester group is selected from at least one of phosphate monoester group, phosphate diester group, and phosphate triester group.

[0041] In some embodiments of the present invention, it is further preferred that the isocyanate group is selected from at least one of cyclohexyl isocyanate group, phenyl isocyanate group, toluene isocyanate group, 2-naphthyl isocyanate group, and alkyl isocyanate group having 2-32 carbon atoms; the alkyl isocyanate group having 2-32 carbon atoms particularly refers to a straight-chain alkyl isocyanate group having 2-32 carbon atoms. In the present invention, compared with uncapped additives, capped additives not only have a higher dispersing effect but also do not adversely affect battery performance.

[0042] In some embodiments of the present invention, preferably, the weight-average molecular weight of the additive is 500-20000 g / mol, for example, 500 g / mol, 2000 g / mol, 3000 g / mol, 5000 g / mol, 7000 g / mol, 10000 g / mol, 12000 g / mol, 15000 g / mol, 18000 g / mol, 20000 g / mol, and any value within the range of any two values, preferably 2000-15000 g / mol.

[0043] In this invention, when the weight-average molecular weight of the additive is greater than 20,000 g / mol, the viscosity of the slurry increases, making it difficult for the solid electrolyte particles to disperse evenly; when the weight-average molecular weight of the additive is less than 500 g / mol, the steric hindrance layer formed on the surface of the solid particles is thin and cannot effectively hinder the interparticle forces, resulting in insufficient reduction of the attraction between solid particles and easy aggregation.

[0044] In some embodiments of the present invention, preferably, the solubility of the additive in the electrolyte is ≤10000ppm, more preferably ≤100ppm, and the electrolyte is selected from one of EC, EMC, DMC, and DEC.

[0045] In some embodiments of the present invention, preferably, the mass ratio of the solid oxide particles to the additive in the dispersion is 100:0.1-10, for example, 100:0.1, 100:0.5, 100:0.8, 100:1, 100:1.5, 100:2, 100:2.5, 100:3, 100:4, 100:5, 100:8, 100:10, and any value within any range of any two values, preferably 100:0.1-5, more preferably 100:0.5-3. Using the above-mentioned mass ratio range is more beneficial for optimizing the viscosity, solid content change rate, and particle size change rate of the dispersion.

[0046] In some embodiments of the present invention, preferably, the solid content of the dispersion is ≥30 wt%, more preferably 30-85 wt%, for example, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 60 wt%, 70 wt%, 80 wt%, 85 wt%, and any value within any range of any two values. If the solid content of the dispersion is low (<30 wt%), it is difficult to maintain the sedimentation stability of the slurry.

[0047] In this invention, the solid content refers to the content of solid oxide particles = (mass of solid oxide particles) / (total mass of dispersion) = (mass of solid oxide particles) / (total mass of solid oxide particles + additives + solvent).

[0048] In this invention, the dispersion contains other additive components besides the additives, solid oxide particles, and solvent, such as thickeners. Preferably, the dispersion consists of solid oxide particles, additives, and solvent.

[0049] In some embodiments of the present invention, preferably, the average particle size of the solid oxide particles is 0.5-1000 μm, referring to the particle size of the solid oxide particle raw material. In the present invention, powders smaller than 0.5 μm are difficult to obtain, and those larger than 1000 μm are lumps, both of which are materials that are difficult to process or cannot be directly ground in actual processing. In fact, strictly speaking, there is no need to limit the particle size of the original powder; as long as it is an electrolyte, it can be processed into a slurry.

[0050] In some embodiments of the present invention, preferably, the solid oxide particles are selected from solid electrolytes, and more preferably 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 At least one of Na-β / β″-Al2O3, wherein M is selected from at least one of Nb, Ta and Sb, M' or M″ is selected from at least one of F, Cl, Br and I, 0≤x1≤0.7, 0≤x2<1, 0≤x3<1, 0<y1<0.1.

[0051] In some embodiments of the present invention, preferably, the solvent is selected from at least one of N-methylpyrrolidone, N,N-dimethylformamide, dimethylacetamide, 1,3-dioxolane, and water.

[0052] In some embodiments of the present invention, preferably, the viscosity of the dispersion is 1000-10000 mPa·s, for example, 1000 mPa·s, 1500 mPa·s, 2000 mPa·s, 3000 mPa·s, 4000 mPa·s, 5000 mPa·s, 6000 mPa·s, 7000 mPa·s, 8000 mPa·s, 9000 mPa·s, 10000 mPa·s, and any value within the range of any two values, preferably 1500-5000 mPa·s.

[0053] In this invention, unless otherwise specified, the viscosity parameters are measured using a rotor viscometer, model: NDJ-8S, rotor No. 4, rotation speed: 60 rpm. The rotor rotates in the test sample for 2 minutes, and the data acquisition time is 1 minute. After the test, the values ​​are recorded.

[0054] In some embodiments of the present invention, preferably, the particle size D of the dispersion is... 50The particle size is 100-1000 nm, for example, 100 nm, 120 nm, 150 nm, 170 nm, 200 nm, 250 nm, 300 nm, 350 nm, 380 nm, 400 nm, 450 nm, 480 nm, 500 nm, 550 nm, 600 nm, 650 nm, 700 nm, 750 nm, 800 nm, 850 nm, 900 nm, 950 nm, 1000 nm, and any value within any range of two values, preferably 150-500 nm, and most preferably 170-380 nm. In this invention, the particle size D... 50 All values ​​refer to the volumetric particle size of the solid oxide particles in the dispersion.

[0055] In some embodiments of the present invention, preferably, the solid content change rate P of the dispersion is ≤5%, for example, 5%, 4.7%, 4.5%, 4.3%, 4.0%, 3.7%, 3.5%, 3.3%, 3.2%, 3.0%, 2.7%, 2.5%, 2.3%, 2.2%, and any value within any range of any two values; preferably, P is ≤2%, for example, 2%, 1.9%, 1.7%, 1.5%, 1.3%, 1.0%, 0.7%, 0.5%, 0.3%, 0.2%, 0.1%, and any value within any range of any two values; the solid content change rate refers to the ratio of the change in solid content of the dispersion after standing for 30 days to the initial solid content, that is, the dispersion in the upper or lower layer after standing for 30 days needs to meet the above range.

[0056] In this invention, unless otherwise specified, the solid content change rate P of the dispersion is measured by the drying method, and the specific test steps are as follows:

[0057] (1) Take the prepared dispersion and test its solid content, and record it as the initial solid content w0;

[0058] (2) Take 100 mL of dispersion into a 150 mL experimental bottle, seal the experimental bottle and let it stand for 30 days; after 30 days, take 1 mL of dispersion from 5 mm away from the liquid surface in the experimental bottle, test the solid content, and record it as the upper solid content value w1 of the dispersion; take 1 mL of dispersion from 5 mm away from the bottom of the experimental bottle, test the solid content, and record it as the lower solid content value w2 of the dispersion.

[0059] (3) The deviation of the solid content values ​​w1 and w2 of the upper and lower layers from the initial solid content value w0 is used to measure the change rate P of the solid content of the dispersion. The change rate of the upper solid content is P1 = |w1-w0| / w0×100%, and the change rate of the lower solid content is P2 = |w2-w0| / w0×100%. The smaller the values ​​of P1 and P2, the more stable the solid content of the upper and lower layers of the dispersion.

[0060] In some embodiments of the present invention, preferably, the particle size change rate T of the dispersion is ≤15%, for example, 15%, 14.5%, 14%, 13.5%, 13%, 12.5%, 12%, 11.5%, 11%, 10.5%, and any value within the range of any two values; preferably, T is ≤10%, for example, 10%, 9.5%, 9%, 8.5%, 8%, 7.5%, 7%, 6.5%, 6%, 5.5%, 5.0%, 4.5%, 4%, 3.5%, 3%, 2.5%, 2%, 1.5%, 1%, 0.5%, and any value within the range of any two values; the particle size change rate refers to the particle size D of the dispersion after standing for 30 days. 50 The rate of change, that is, the dispersion in the upper or lower layer after standing for 30 days, must meet the above range.

[0061] In this invention, unless otherwise specified, the particle size change rate T of the dispersion is measured using a laser particle size analyzer to determine the particle size D of the dispersion. 50 The solvent used in the selected test injector was deionized water. A sample of the dispersion was added dropwise to the test injector for testing. The test parameters were set as follows: material refractive index 2.42, absorptivity 1.0, and opacity 1-4%. The specific test steps are as follows:

[0062] (1) Take the prepared dispersion and test the particle size, and record it as the initial average particle size D0;

[0063] (2) Take 100 mL of dispersion into a 150 mL experimental bottle, seal the experimental bottle and let it stand for 30 days; after 30 days, take 1 mL of dispersion from 5 mm away from the liquid surface in the experimental bottle, test the particle size and record it as the upper layer particle size value D1; take 1 mL of dispersion from 5 mm away from the bottom of the experimental bottle, test the particle size and record it as the lower layer particle size value D2.

[0064] (3) The particle size change rate T of the dispersion is measured by the deviation of the upper and lower layer particle size values ​​D1 and D2 from the initial particle size value D0; wherein, the particle size change rate of the upper layer of the dispersion is T1=|D1-D0| / D0×100%, and the particle size change rate of the lower layer is T2=|D2-D0| / D0×100%; the smaller the values ​​of T1 and T2, the more stable the particle size of the upper and lower layers of the dispersion.

[0065] In this invention, the preparation method of the dispersion has a wide range of options. Preferably, the dispersion is obtained by grinding a slurry containing the solid oxide particles, additives, and solvent.

[0066] In this invention, unless otherwise specified, a slurry containing the solid oxide particles, additives, and solvent refers to a slurry obtained by mixing the solid oxide particles, additives, and solvents. Preferably, the mixing conditions include: a temperature of 20-40°C, more preferably 25-30°C; and a time of 0.1-10 h, more preferably 0.1-2 h.

[0067] In some embodiments of the present invention, preferably, the grinding conditions include a linear velocity of 1-45 m / s, more preferably 1-20 m / s.

[0068] In this invention, the grinding method has a wide range of choices, including but not limited to ball milling, sand milling, etc.

[0069] In some embodiments of the present invention, preferably, the grinding process includes grinding the slurry and the grinding media, wherein the mass ratio of the grinding media to the solid oxide particles is 1-20:1, for example, 1:1, 3:1, 5:1, 8:1, 10:1, 15:1, 20:1, and any value within the range of any two values, preferably 3-10:1.

[0070] In some embodiments of the present invention, preferably, the average particle size of the grinding media is 0.1-10 mm, for example, 0.1 mm, 0.5 mm, 1 mm, 2 mm, 5 mm, 10 mm, or any value within a range of any two values. In the present invention, the material of the grinding media includes, but is not limited to, zirconium balls.

[0071] The second aspect of the present invention provides an application of the dispersion provided in the first aspect in positive and negative electrode mixing, membrane coating, electrode surface coating, and organic / inorganic composite solid electrolytes.

[0072] A third aspect of the present invention provides a lithium-ion secondary battery, wherein the lithium-ion secondary battery contains the dispersion provided in the first aspect.

[0073] In this invention, the lithium-ion secondary battery containing the above-mentioned dispersion has excellent electrochemical performance, especially rate performance.

[0074] The present invention will be described in detail below through embodiments.

[0075] The physical properties of the dispersions obtained in Examples 1-5 and Comparative Examples 1-4 are listed in Tables 1-3.

[0076] Example 1

[0077] (1) Preparation of additive A1

[0078] 200g of tris-(2-aminoethyl)amine was added to a reactor, followed by 0.6g of sodium methoxide and stirring. The reactor was heated to 85°C and dehydrated for 1 hour. Once the moisture content reached the target level, the temperature was further increased to 140°C under nitrogen protection. 330g of ethylene oxide (EO) was slowly added to the reactor and allowed to mature. The reaction was continued for 4 hours. Then, 460g of propylene oxide (PO) was added, and the reaction was continued for 4 hours at a pressure of 4 MPa to obtain compound A1' with the structure shown in S5.

[0079]

[0080] Based on the molar number of terminal hydroxyl groups in compound A1', 20 equivalents of n-hexyl isocyanate were added dropwise at room temperature, and the mixture was stirred thoroughly while maintaining the temperature inside the vessel at no more than 50°C. After the addition was completed, the mixture was stirred at room temperature for 2 hours. 50 mL of water was added, and the organic layer was washed and extracted. After drying, dichloromethane was removed under reduced pressure. The H in compound A1' was replaced by n-hexyl isocyanate groups to obtain additive A1, with a weight-average molecular weight of 4324 g / mol.

[0081] (2) Preparation of dispersion Q1

[0082] 100 parts by weight of solid oxide particles (lithium aluminum titanium phosphate LATP, average particle size D) 50 2 parts by weight of additive A1 (2 μm), 3000 parts by weight of grinding media (zirconium balls, average particle size 0.3 mm) and NMP were mixed, and the resulting slurry was ground in a sand mill (linear speed 20 m / s, time 15 h) to obtain dispersion Q1.

[0083] The viscosity of the dispersion Q1 is 1902 mPa·s; the solid content is 34.96 wt%; and the particle size D is... 50 The particle size was 189 nm (the test method involved dispersing the slurry in NMP with a refractive index of 2.42 and an absorptivity of 1.0 to test the laser particle size).

[0084] Example 2

[0085] (1) Preparation of additive A2

[0086] The method is the same as in Example 1, except that...

[0087] Replacing 200g of tri-(2-aminoethyl)amine with 200g of triethylenetetramine, while keeping all other conditions the same, yielded compound A2' with the structure shown in S4.

[0088]

[0089] Meanwhile, the H in compound A2' was replaced by a hexyl isocyanate group to obtain additive A2, with a weight-average molecular weight of 4005 g / mol.

[0090] (2) Preparation of dispersion Q2

[0091] The method is the same as in Example 1, except that...

[0092] Replace additive A1 with additive A2, and keep all other conditions the same to obtain dispersion Q2.

[0093] The viscosity of the dispersion Q2 is 2345 mPa·s; the solid content is 35.36 wt%; and the particle size D is... 50 The wavelength is 222nm (testing method is the same as in Example 1).

[0094] Example 3

[0095] (1) Preparation of Additive A3

[0096] The method is the same as in Example 1, except that...

[0097] By replacing 200g of tris-(2-aminoethyl)amine with 200g of ethylenediamine, and keeping all other conditions the same, compound A3' with the structure shown in S2 was obtained;

[0098]

[0099] Meanwhile, the H in compound A3' was replaced by a hexyl isocyanate group to obtain additive A3, with a weight-average molecular weight of 4198 g / mol.

[0100] (2) Preparation of dispersion Q3

[0101] The method is the same as in Example 1, except that...

[0102] Replace additive A1 with additive A3, and keep all other conditions the same to obtain dispersion Q3.

[0103] The viscosity of the dispersion Q3 is 2453 mPa·s; the solid content is 35.91 wt%; and the particle size D is... 50 The wavelength is 213nm (testing method is the same as in Example 1).

[0104] Example 4

[0105] (1) Preparation of Additive A4

[0106] 100g of sample A1' from Example 1 was added to a reaction vessel, along with 0.1% (by weight) molecular sieve. The mixture was shaken or stirred, and the moisture content was measured. When the moisture content was below 100 ppm, the material containing the molecular sieve was heated to 45°C. Under nitrogen protection, 0.003 mol of phosphorus pentoxide (the molar content of phosphorus pentoxide is 1 mol% of the hydroxyl groups in A1') was added to the reaction vessel in 5 portions over 1.5 hours. During the addition process, the temperature inside the vessel was kept below 60°C. After the addition was completed, the mixture was kept at 50°C for 30 minutes, then heated to 85°C and kept at that temperature for another 4 hours. After the reaction was completed, the reactants were filtered to remove the molecular sieve. The mixture was then added back to the reaction vessel, along with water (the mass ratio of water to phosphorus pentoxide was 5 / 100), and kept at 90°C for 2 hours to obtain the phosphate ester modified sample, i.e., additive A4, where X is a phosphate diester group with a weight-average molecular weight of 4524 g / mol.

[0107] (2) Preparation of dispersion Q4

[0108] 100 parts by weight of solid oxide particles (Li 1.5 Al 0.5 Ge 1.5 (PO4)3, also known as LAGP, has an average particle size D 50 2 parts by weight of additive A4 (2 μm), 3000 parts by weight of grinding media (zirconium balls with an average particle size of 0.3 mm) and DMF were mixed, and the resulting slurry was ground in a sand mill (linear speed of 20 m / s for 15 h) to obtain dispersion Q4.

[0109] The viscosity of the above dispersion Q4 is 1984 mPa·s; the solid content is 35.01 wt%; and the particle size D is... 50 The value is 223 nm (the test method involves dispersing the slurry in DMF, with a refractive index of 2.1 and an absorptivity of 0.1 to test the laser particle size).

[0110] Example 5

[0111] (1) Preparation of additive A5

[0112] The method is the same as in Example 1, except that...

[0113] Without adding hexyl isocyanate, and with all other conditions being the same, compound A1' was used as additive A5, with a weight-average molecular weight of 3900 g / mol.

[0114] (2) Preparation of dispersion Q5

[0115] The method is the same as in Example 1, except that...

[0116] Replace additive A1 with additive A5, and keep all other conditions the same to obtain dispersion Q5.

[0117] The viscosity of the dispersion Q5 is 1945 mPa·s; the solid content is 35.98 wt%; and the particle size D is... 50 The wavelength is 203nm (testing method is the same as in Example 1).

[0118] Comparative Example 1

[0119] The method is the same as in Example 1, except that...

[0120] Without the addition of additive A1, dispersion DQ1 was obtained.

[0121] The viscosity of the above dispersion DQ1 is 3746 mPa·s; the solid content is 35.25 wt%; and the particle size D... 50 The wavelength is 216nm (testing method is the same as in Example 1).

[0122] Comparative Example 2

[0123] The method is the same as in Example 1, except that...

[0124] Two parts by weight of additive A1 were replaced with two parts by weight of fatty alcohol polyoxyethylene ether (AEO-9, West Asia, weight average molecular weight of 4256 g / mol), and the other conditions remained the same, to obtain dispersion DQ2.

[0125] The viscosity of the above dispersion DQ2 is 3264 mPa·s; the solid content is 35.06 wt%; and the particle size D... 50 The wavelength is 234nm (testing method is the same as in Example 1).

[0126] Comparative Example 3

[0127] The method is the same as in Example 1, except that...

[0128] Two parts by weight of additive A1 were replaced with two parts by weight of polyetheramine (JEFFAMINE D-230, Guangzhou Senmao New Materials Co., Ltd., with a weight-average molecular weight of 4683 g / mol), and the other conditions remained the same, to obtain dispersion DQ3.

[0129] The viscosity of the above dispersion DQ3 is 3159 mPa·s; the solid content is 35.12 wt%; and the particle size D... 50 The wavelength is 456nm (testing method is the same as in Example 1).

[0130] Comparative Example 4

[0131] The method is the same as in Example 1, except that...

[0132] Two parts by weight of additive A1 were replaced with four parts by weight of a 40 wt% aqueous solution of polymaleic acid (CAS: 26099-09-2, weight-average molecular weight 4255 g / mol), and the other conditions remained the same, to obtain dispersion DQ4.

[0133] The viscosity of the above dispersion DQ4 is 5634 mPa·s; the solid content is 34.93 wt%; and the particle size is D. 50 The wavelength is 236nm (testing method is the same as in Example 1).

[0134] Table 1

[0135]

[0136]

[0137] As can be seen from the results in Table 1, compared with Comparative Examples 1-4, Examples 1-5, using the dispersion provided by this invention, that is, with only specific additives, not only have lower viscosity and D... 50 This also ensures that the solid content change rate P ≤ 5% and the particle size change rate T ≤ 15%.

[0138] Test Example 1

[0139] The dispersions obtained in Examples 1 and 5 were subjected to solubility parameter tests, and the test results are listed in Table 2. The test methods included:

[0140] (1) Prepare mixed solutions of additives and electrolyte (EC:EMC volume ratio of 3:7) with concentrations of 0, 20, 40, 60, 80, 100, 150, and 200 ppm, test the transmittance of the mixed solutions, and determine the solubility of the additives.

[0141] (2) If the solubility exceeds 200 ppm, increase the amount of additive by 2000 ppm and observe the solubility of the additive in the electrolyte until the additive is completely dissolved.

[0142] Table 2

[0143] EC / DMC solubility, ppm Example 1 9 Example 5 19783

[0144] Test Example 2

[0145] The dispersions prepared in Example 1 and Comparative Example 1 were subjected to electrical performance tests, and the test results are listed in Table 3.

[0146] The test methods include: (1) mixing the above dispersion and positive electrode slurry, coating to make a positive electrode sheet, and finally assembling a coin cell for testing; (2) comparing the battery test results with the blank sample without solid oxide dispersion, and calculating the relative value of the improvement in electrical performance.

[0147] Cycle performance testing method: The 2032 button cell has a charge / discharge voltage range of 3.0-4.2V and a charge / discharge rate of 0.1 / 0.2 / 0.5 / 1.0 / 2.0 / 3.0 / 0.1C, with 2 cycles at each rate.

[0148] Table 3

[0149]

[0150] As shown in Table 2-3, compared with the solubility of Examples 1 and 5, the end capping reduces the solubility of the dispersant in the electrolyte. Compared with the rate performance of Example 1 and Comparative Example 1, the addition of a dispersant to the surface significantly improves the battery performance at high rates.

[0151] 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 combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as disclosed in the present invention.

Claims

1. A solid oxide particulate dispersion, characterized by, The dispersion liquid comprises: solid oxide particles, an additive, and a solvent; The additive is selected from at least one of the structures shown in formulas S1-S17; wherein R1-R9 are each independently selected from H, substituted or unsubstituted C1-C6 alkyl, alkoxy chain, and at least one of R1-R9 is selected from an alkoxy chain; n1-n6 are each independently selected from an integer from 1 to 6.

2. The dispersion of claim 1, wherein, In formulas S1-S17, when any two of R1-R9 are connected to the same N, at least one is selected from an alkoxy chain; Preferably, in formulas S1-S17, when any two of R1-R9 are connected to the same N, both are selected from an alkoxy chain; Preferably, in formulas S1-S17, n1-n6 are each independently selected from an integer from 1 to 5, preferably from an integer from 2 to 4.

3. The dispersion of claim 2, wherein, In the formulae S1-S17, the general formula of the alkoxy chain is: wherein R a and R b are each selected from C2-C 18 alkylene, m1 and m2 are each selected from an integer from 0 to 50, and m1 and m2 are not simultaneously 0, and X is a capping group or an uncapping group.

4. The dispersion of claim 3, wherein, In formula I, R a and R b are each selected from C2-C 10 alkylene, preferably C2-C6alkylene, more preferably C2-C4alkylene; Preferably, m1 and m2 are each independently selected from an integer from 2 to 10; Preferably, X is selected from at least one of hydrogen, a phosphate group, and an isocyanate group, preferably selected from a phosphate group and / or an isocyanate group; Further preferably, the phosphate group is selected from at least one of a mono-phosphate group, a di-phosphate group, and a tri-phosphate group; Further preferably, the isocyanate group is selected from at least one of a cyclohexyl isocyanate group, a phenyl isocyanate group, a tolyl isocyanate group, a 2-naphthyl isocyanate group, and an alkyl isocyanate group having a carbon number from 2 to 32.

5. The dispersion liquid according to any one of claims 1-4, preferably, the additive has a weight average molecular weight of 500-20000 g / mol, preferably 2000-15000 g / mol.

6. The dispersion of any one of claims 1-5, wherein, In the dispersion liquid, the mass ratio of the solid oxide particles to the additive is 100:0.1-10, preferably 100:0.1-5, more preferably 100:0.5-3; Preferably, the dispersion liquid has a solid content of ≥30 wt%, preferably 30-85 wt%; Preferably, the dispersion liquid is composed of the solid oxide particles, the additive, and the solvent; Preferably, the solid oxide particles have an average particle size of 0.5-1000 μm; Preferably, the solid oxide particles are selected from solid electrolytes, and more preferably 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 At least one of Na-β / β″-Al2O3, wherein M is selected from at least one of Nb, Ta and Sb, and M' or M″ is selected from at least one of F, Cl, Br and I, 0≤x1≤0.7, 0≤x2<1, 0≤x3<1, 0<y1<0.1; Preferably, the solvent is selected from at least one of N-methyl pyrrolidone, N,N-dimethyl formamide, dimethyl acetamide, 1,3-dioxolane, and water.

7. The dispersion of any one of claims 1-6, wherein, The dispersion liquid has a viscosity of 1000-10000 mPa·s, preferably 1500-5000 mPa·s; Preferably, the particle size D 50 is 100-1000 nm, preferably 150-500 nm, most preferably 170-380 nm; Preferably, the dispersion liquid has a solid content variation rate P≤5%, preferably P≤2%, the solid content variation rate refers to the solid content variation rate of the dispersion liquid after standing for 30 days; Preferably, the dispersion has a particle size variation rate T < 15%, preferably T < 10%, the particle size variation rate being the variation of the particle size D 50 of the dispersion after 30 days of rest.

8. The dispersion of any one of claims 1-7, wherein, The dispersion liquid is prepared by grinding a slurry containing the solid oxide particles, the additive, and the solvent; Preferably, the grinding conditions include: a linear velocity of 1-45 m / s, preferably 1-20 m / s.

9. Use of the dispersion liquid according to any one of claims 1-8 in positive / negative electrode blending, separator coating, electrode surface coating, and organic / inorganic composite solid electrolyte.

10. A lithium-ion secondary battery, characterized by comprising: The lithium ion secondary battery contains the dispersion liquid according to any one of claims 1-8.

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