Diaphragm slurry

Abstract

The invention belongs to the technical field of diaphragm slurry, and provides diaphragm slurry which comprises a first slurry solution and a second slurry solution, the first slurry solution comprises one or more of oxide solid electrolyte particles or nanometer dispersion slurry and a first solvent, and the solid content of the first slurry solution is 10 wt%-70 wt%; the solid mass ratio of the first slurry to the fluorine-free polymer is (10: 1)-(1: 3), oxide solid electrolyte particles are modified in a manner of organic coating treatment, inorganic coating treatment or combination of the organic coating treatment and the inorganic coating treatment, so that the problem of discoloration or gelation of the diaphragm slurry is solved; and stable diaphragm slurry is obtained.

Description

Technical Field

[0001] The present invention relates to a separator slurry, in particular to a separator slurry for coating on a battery separator. Background Art

[0002] In the prior art, a solid electrolyte composite diaphragm includes a base membrane and a solid electrolyte coating mixed with a fluoropolymer, which is formed on the surface of the base membrane. During the preparation of the diaphragm slurry, the oxide solid electrolyte is alkaline in aqueous solutions, and the fluoropolymer generates a reversible intermediate under alkaline conditions. The intermediate dehydrofluorinates in an aprotic polar solvent to generate a brown-black poly(monofluoroacetylene) having a conjugated diene, a double carbon-fluorine bond, and a saturated carbon-fluorine bond structure. As a result, the prepared diaphragm slurry is prone to discoloration, gelation, and failure of the finished slurry. When applied to the diaphragm, the coating is prone to poor surface area, instability, or coating omissions. Consequently, the electrochemical performance of batteries made with the above-mentioned solid electrolyte composite diaphragms is unstable, and they are prone to problems such as reduced initial efficiency, battery capacity decay, decreased cycle performance, or decreased rate performance.

[0003] In view of the above-mentioned problems, it is necessary to provide a diaphragm slurry that can prevent the slurry from deteriorating or gelling. Summary of the Invention

[0004] The problem to be solved by the present invention is to provide a diaphragm slurry that can prevent the slurry from deteriorating or gelling.

[0005] To achieve the above-mentioned object, the present invention provides a diaphragm slurry, characterized in that it comprises: a first slurry solution, comprising: one or more of oxide solid electrolyte particles or nano-dispersed slurry, and a first solvent, wherein the solid content of the first slurry solution is 10wt% to 70wt%; and a fluorine-free polymer, wherein the solid mass ratio of the first slurry to the fluorine-free polymer is 10:1 to 1:3.

[0006] More preferably, the method further comprises a pretreatment solution comprising an organic acid, an alkali-resistant polymer, a second solvent, and a buffered salt solution.

[0007] More preferably, the concentration of the pretreatment solution is 0.1 to 15%; the buffered saline solution contains ammonium sulfite at a concentration of 3%; the mass ratio of the mixture of the organic acid, the alkali-resistant polymer, and the second solvent to the buffered saline solution is 10:1 to 1:50; or the mass ratio of the mixture of the organic acid, the alkali-resistant polymer, and the second solvent to the buffered saline solution is 5:1.

[0008] More preferably, the method further comprises: a polymer glue, wherein the polymer comprises: a second fluorine-containing polymer and a third solvent.

[0009] More preferably, the nano-dispersed slurry comprises: an inorganic coated composite material, a fifth solvent, and a second dispersant.

[0010] More preferably, the inorganic coating composite material comprises oxide solid electrolyte particles and oxide coating material.

[0011] The present invention further provides a diaphragm slurry, characterized by comprising: an inorganic coating composite material, a fifth solvent, and a second dispersant.

[0012] More preferably, the inorganic coated composite material, the fifth solvent, and the second dispersant are stirred and mixed at a rotation speed of 350 rpm for 2 hours, and the particle size D50 of the solid particles contained in the diaphragm slurry is 500 nm.

[0013] More preferably, it further comprises: a pretreatment solution, and one or more of a fluorine-containing polymer or a fluorine-free polymer.

[0014] More preferably, the pretreatment solution comprises: an organic acid, an inorganic acid, an alkali-resistant polymer, a second solvent, and a buffered saline solution, wherein the weight ratio of a mixture of one or more of the organic acid, the inorganic acid, the alkali-resistant polymer, and the second solvent to the buffered saline solution is 10:1 to 1:50.

[0015] More preferably, the concentration of the pretreatment solution is 0.1 to 15%; the buffered salt solution contains ammonium sulfite with a concentration of 3%; or the mass ratio of a mixture of the organic acid, the inorganic acid, the alkali-resistant polymer, and one or more of the second solvent to the buffered salt solution is 5:1.

[0016] The present invention further provides a diaphragm slurry, characterized in that it comprises: a nano-dispersed slurry and a polymer glue.

[0017] More preferably, the polymer glue comprises: a second fluorine-containing polymer and a third solvent.

[0018] The present invention further provides a diaphragm slurry, characterized in that it comprises: a polymer glue and an electrolyte slurry.

[0019] More preferably, the pH value of the electrolyte slurry is 4.5 to 6.5.

[0020] The present invention is more effective than the prior art in that, in the prior art, the alkaline oxide solid electrolyte will discolor and gel after being mixed with the fluoropolymer, which makes it impossible to evenly and stably apply the slurry to the diaphragm base film. Since the membrane surface of the battery diaphragm obtained after applying the slurry contains obvious defects, the electrochemical performance of the battery made with the above-mentioned battery diaphragm is unstable. The diaphragm slurry prepared by the present invention can avoid the defects of the prior art. Specifically, the present invention modifies the raw materials by inorganic coating treatment or organic coating treatment to solve the problem of discoloration or gelation of the diaphragm slurry and obtain a stable diaphragm slurry. After the diaphragm slurry prepared by the present invention is applied to the base film, a solid electrolyte composite diaphragm with high ionic conductivity can be prepared, and when the battery is prepared with the diaphragm slurry, it can ensure that the battery has excellent electrochemical performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a flow chart for illustrating the preparation process of the first embodiment of the diaphragm slurry;

[0022] Figure 2 is a flow chart for illustrating the preparation process of the second embodiment of the diaphragm slurry;

[0023] Figure 3 is a flow chart for illustrating the preparation process of the third embodiment of the diaphragm slurry;

[0024] Figure 4 is a flow chart for illustrating the preparation process of the fourth embodiment of the diaphragm slurry;

[0025] Figure 5 is a flow chart for illustrating the preparation process of the fifth embodiment of the diaphragm slurry;

[0026] Figure 6 is a flow chart for illustrating the preparation process of the sixth embodiment of the diaphragm slurry;

[0027] Figure 7 1 is a flow chart for illustrating the preparation process of the seventh embodiment of the diaphragm slurry. DETAILED DESCRIPTION

[0028] To make the above and / or other purposes, effects, and features of the present invention more clearly understood, preferred embodiments are described in detail below:

[0029] The present invention provides a diaphragm slurry comprising: a first slurry solution containing one or more of oxide solid electrolyte particles or nanodispersed slurry, and a first solvent, wherein the solid content of the first slurry solution is 10 wt% to 70 wt%, but not limited thereto; and a fluorine-free polymer, wherein the solid mass ratio of the first slurry to the fluorine-free polymer is 10:1 to 1:3, but not limited thereto. In a preferred embodiment, the slurry further comprises a pretreatment solution containing, but not limited to, an organic acid, an alkali-resistant polymer, a second solvent, and a buffered salt solution. In another preferred embodiment, the concentration of the pretreatment solution is 0.1 to 15%, but not limited thereto; the buffered salt solution contains ammonium sulfite at a concentration of 3%, but not limited thereto; the mass ratio of the mixture of the organic acid, the alkali-resistant polymer, and the second solvent to the buffered salt solution is 10:1 to 1:50, but not limited thereto; or the mass ratio of the mixture of the organic acid, the alkali-resistant polymer, and the second solvent to the buffered salt solution is 5:1, but not limited thereto. In another preferred embodiment, it further comprises: a polymer glue comprising: a second fluorine-containing polymer and a third solvent, but not limited thereto. In another preferred embodiment, the nano-dispersed slurry comprises: an inorganic coated composite material, a fifth solvent, and a second dispersant, but not limited thereto. In another preferred embodiment, the inorganic coated composite material comprises: oxide solid electrolyte particles and an oxide coating material, but not limited thereto.

[0030] Another object of the present invention is to provide a diaphragm slurry, characterized in that it comprises: an inorganic coated composite material, a fifth solvent, and a second dispersant, but is not limited thereto. In a preferred embodiment, the inorganic coated composite material, the fifth solvent, and the second dispersant are stirred and mixed at a speed of 350 rpm for 2 hours, and the particle size D50 of the solid particles contained in the diaphragm slurry is 500 nm, but is not limited thereto. In another preferred embodiment, it further comprises: a pretreatment solution, and one or more of a fluoropolymer or a fluoropolymer-free polymer, but is not limited thereto. In another preferred embodiment, the pretreatment solution comprises: an organic acid, an inorganic acid, an alkali-resistant polymer, a second solvent, and a buffered salt solution, wherein the weight ratio of the mixture of one or more of the organic acid, the inorganic acid, the alkali-resistant polymer, and the second solvent to the buffered salt solution is 10:1 to 1:50, but is not limited thereto. In another preferred embodiment, the concentration of the pretreatment solution is 0.1 to 15%, but not limited thereto; the buffered salt solution contains ammonium sulfite at a concentration of 3%, but not limited thereto; or the mass ratio of a mixture of one or more of the organic acid, the inorganic acid, the alkali-resistant polymer, and the second solvent to the buffered salt solution is 5:1, but not limited thereto.

[0031] Another object of the present invention is to provide a diaphragm slurry comprising, but not limited to, a nano-dispersed slurry and a polymer glue. In a preferred embodiment, the polymer glue comprises, but not limited to, a second fluorinated polymer and a third solvent.

[0032] Another object of the present invention is to provide a separator slurry, characterized by comprising: a polymer glue and an electrolyte slurry, but not limited thereto. In a preferred embodiment, the pH value of the electrolyte slurry is 4.5 to 6.5, but not limited thereto.

[0033] The following is a first embodiment of a method for preparing a diaphragm slurry.

[0034] The object of the present invention is to provide a method for preparing a diaphragm slurry, wherein Figure 1 As shown, it includes: (S1) an organic coating treatment step, comprising: selecting one or more oxide solid electrolyte particles or nano-dispersed slurry, and stirring and mixing with a first solvent to obtain a first slurry solution, wherein the solid content of the first slurry solution is 10wt% to 70wt%; and stirring and mixing with a fluorine-free polymer at a solid mass ratio of 10:1 to 1:3 to obtain an organic coating composite material. The organic coating composite material can be used as a separator slurry.

[0035] More preferably, one or more of the oxide solid electrolyte particles or the nano-dispersed slurry is stirred and mixed with the first solvent at a rotation speed of 2000 rpm for 4 hours to obtain the first slurry solution, but the present invention is not limited thereto.

[0036] The following provides a second embodiment of the method for preparing the diaphragm slurry.

[0037] More preferably, the present invention further provides a method for preparing a diaphragm slurry, wherein Figure 2 As shown, it includes: the above-mentioned (S1) organic coating treatment step; (S2) a pretreatment solution preparation step, including: first stirring and mixing an organic acid, an alkali-resistant polymer, and a second solvent, and then stirring and mixing with a buffered salt solution to obtain the pretreatment solution; and (S3) a first mixing step, stirring and mixing the organic coating composite material and the pretreatment solution to obtain the diaphragm slurry.

[0038] More preferably, the concentration of the pretreatment solution is 0.1 to 15%, but is not limited thereto. In a preferred embodiment, the buffered saline solution comprises ammonium sulfite at a concentration of 3%, but is not limited thereto. In another preferred embodiment, the mass ratio of the mixture of the organic acid, the alkali-resistant polymer, and the second solvent to the buffered saline solution is 10:1 to 1:50, but is not limited thereto. In yet another preferred embodiment, the mass ratio of the mixture of the organic acid, the alkali-resistant polymer, and the second solvent to the buffered saline solution is 5:1, but is not limited thereto.

[0039] The third embodiment of the method for preparing the diaphragm slurry is provided below.

[0040] More preferably, the present invention provides a method for preparing a diaphragm slurry, wherein Figure 3 As shown, it includes: the above-mentioned (S1) organic coating treatment step; (S4) polymer glue preparation step, including: stirring and mixing the second fluorine-containing polymer and the third solvent to obtain the polymer glue; and (S5) a second mixing step, stirring and mixing the organic coating composite material and the polymer glue to obtain the diaphragm slurry.

[0041] The fourth embodiment of the method for preparing the diaphragm slurry is provided below.

[0042] More preferably, the present invention provides a method for preparing a diaphragm slurry, wherein Figure 4As shown, it includes: (S6) an inorganic coating treatment step, comprising: stirring and mixing the oxide solid electrolyte particles, the oxide coating material, and the fourth solvent to obtain a second slurry solution, wherein: based on the total weight of the second slurry solution, it contains 0.001wt% to 5wt% of the oxide coating material; mixing the second slurry solution with the first dispersant, and performing ball milling dispersion to obtain a mixed material; and drying and sintering the mixed material in sequence to obtain an inorganic coated composite material; and (S11) a nano-dispersed slurry preparation step, comprising: mixing the inorganic coated composite material, the fifth solvent, and the second dispersant, and performing ball milling dispersion to obtain the nano-dispersed slurry; and (S1) an organic coating treatment step, comprising: stirring and mixing the nano-dispersed slurry with the first solvent to obtain a first slurry solution; and selecting one or more of a first fluorine-containing polymer or a fluorine-free polymer, and stirring and mixing with the first slurry solution to obtain an organic coated composite material. In this embodiment, the oxide solid electrolyte particles are first inorganically coated to obtain an inorganic-coated composite material. Because the particles of the inorganic-coated composite material are too large after sintering, they must first be ball-milled to obtain a nano-dispersed slurry. This nano-dispersed slurry is then organically coated to prepare an organic-coated composite material. This organic-coated composite material can then be used as a separator slurry.

[0043] More preferably, the mixed material is first dried at a temperature of 100° C. to 200° C. for 4 to 48 hours to obtain a dried material, and then the dried material is sintered at a temperature of 350° C. to 1300° C. for 6 to 24 hours to obtain the inorganic coated composite material, but the present invention is not limited thereto. In a preferred embodiment, the inorganic coated composite material, the fifth solvent, and the second dispersant are mixed and then stirred at a speed of 350 rpm for 2 hours to obtain the nano-dispersed slurry, but the present invention is not limited thereto. In another preferred embodiment, a gas atmosphere is used for protection during sintering, wherein the gas atmosphere comprises one or more of nitrogen (N2), helium (He), neon (Ne), argon (Ar), or krypton (Kr), but the present invention is not limited thereto. In another preferred embodiment, the stirring and mixing is carried out at a speed of 350 to 2100 rpm for 2 to 4 hours, but the present invention is not limited thereto. In another preferred embodiment, the particle size D50 of the solid particles contained in the nano-dispersed slurry is 500 nm, but not limited thereto.

[0044] The fifth embodiment of the method for preparing the diaphragm slurry is provided below

[0045] More preferably, the present invention provides a method for preparing a diaphragm slurry, wherein Figure 5As shown, it includes: (S6) an inorganic coating treatment step, including: stirring and mixing the oxide solid electrolyte particles, the oxide coating material, and the fourth solvent to obtain a second slurry solution, wherein: based on the total weight of the second slurry solution, it contains 0.001wt% to 5wt% of the oxide coating material; mixing the second slurry solution with the first dispersant and performing ball milling dispersion to obtain a mixed material; and drying and sintering the mixed material in sequence to obtain an inorganic coated composite material; (S11) a nano-dispersed slurry preparation step, including: mixing the inorganic coated composite material, the fifth solvent, and the second dispersant, and performing ball milling dispersion to obtain the nano-dispersed slurry; (S2) a pretreatment solution preparation step, including: first stirring and mixing the organic acid, the alkali-resistant polymer, and the second solvent, and then stirring and mixing with the buffered salt solution to obtain the pretreatment solution; and (S7) a third mixing step, stirring and mixing the nano-dispersed slurry with the pretreatment solution to obtain the diaphragm slurry.

[0046] More preferably, the mixed material is first dried at a temperature of 100° C. to 200° C. for 4 to 48 hours to obtain a dried material, and then the dried material is sintered at a temperature of 350° C. to 1300° C. for 6 to 24 hours to obtain the inorganic coated composite material, but the present invention is not limited thereto. In a preferred embodiment, the inorganic coated composite material, the fifth solvent, and the second dispersant are mixed and then stirred at a speed of 350 rpm for 2 hours to obtain the nano-dispersed slurry, but the present invention is not limited thereto. In another preferred embodiment, a gas atmosphere is used for protection during sintering, wherein the gas atmosphere comprises one or more of nitrogen (N2), helium (He), neon (Ne), argon (Ar), or krypton (Kr), but the present invention is not limited thereto. In another preferred embodiment, the stirring and mixing is carried out at a speed of 350 to 2100 rpm for 2 to 4 hours, but the present invention is not limited thereto. In another preferred embodiment, the particle size D50 of the solid particles contained in the nano-dispersed slurry is 500 nm, but not limited thereto. In another preferred embodiment, the concentration of the pretreatment solution is 0.1 to 15%, but not limited thereto. In another preferred embodiment, the buffered saline solution contains ammonium sulfite at a concentration of 3%, but not limited thereto. In another preferred embodiment, the mass ratio of the mixture of the organic acid, the alkali-resistant polymer, and the second solvent to the buffered saline solution is 10:1 to 1:50, but not limited thereto. In another preferred embodiment, the mass ratio of the mixture of the organic acid, the alkali-resistant polymer, and the second solvent to the buffered saline solution is 5:1, but not limited thereto.

[0047] The sixth embodiment of the method for preparing the diaphragm slurry is provided below.

[0048] More preferably, the present invention provides a method for preparing a diaphragm slurry, wherein Figure 6 As shown, it includes: (S6) an inorganic coating treatment step, including: stirring and mixing the oxide solid electrolyte particles, the oxide coating material, and the fourth solvent to obtain a second slurry solution, wherein: based on the total weight of the second slurry solution, it contains 0.001wt% to 5wt% of the oxide coating material; mixing the second slurry solution with the first dispersant, and ball milling to obtain a mixed material; and drying and sintering the mixed material in sequence to obtain an inorganic coated composite material; (S11) a nano-dispersed slurry preparation step, including: mixing the inorganic coated composite material, the fifth solvent, and the second dispersant, and ball milling to obtain the nano-dispersed slurry; (S4) a polymer glue preparation step, stirring and mixing the second fluorine-containing polymer and the third solvent to obtain the polymer glue; and (S8) a fourth mixing step, stirring and mixing the nano-dispersed slurry with the polymer glue to obtain the diaphragm slurry.

[0049] The following provides a seventh embodiment of the method for preparing a diaphragm slurry.

[0050] More preferably, the present invention provides a method for preparing a diaphragm slurry, wherein Figure 7 As shown, it includes: (S4) a polymer glue preparation step, stirring and mixing the second fluorine-containing polymer with the third solvent to obtain the polymer glue; (S9) an electrolyte slurry preparation step, including: first selecting one or more oxide solid electrolyte particles, organic coated composite materials, or nano-dispersed slurries, and stirring and mixing them with a sixth solvent to obtain a third slurry solution; dispersing, filtering and drying the third slurry solution in sequence to obtain an oxide solid electrolyte powder; stirring and mixing the oxide solid electrolyte powder with a seventh solvent to obtain a fourth slurry solution; stirring and mixing one or more organic acids or inorganic acids to obtain a pH regulating solution; and stirring and mixing the fourth slurry solution and the pH regulating solution to obtain the electrolyte slurry; and (S10) a fifth mixing step, stirring and mixing the polymer glue and the electrolyte slurry to obtain the diaphragm slurry. In the electrolyte slurry preparation step (S9), the organic coated composite material is prepared in the organic coating treatment step (S1), or the nano-dispersed slurry is prepared in the inorganic coating treatment step (S6) and the nano-dispersed slurry preparation step (S11). Alternatively, the inorganic coating treatment step (S6), the nano-dispersed slurry preparation step (S11), and the organic coating treatment step (S1) may be performed in sequence, and then the electrolyte slurry preparation step (S9) may be performed using the organic coated composite material.

[0051] More preferably, the third slurry solution is dried at a temperature of 65 to 150° C. for 2 to 24 hours to obtain the oxide solid electrolyte powder, but the invention is not limited thereto. In a preferred embodiment, the oxide solid electrolyte powder is stirred and mixed with the seventh solvent, and then the mixture is milled in a forward and reverse direction for 10 to 60 minutes at a frequency of 32 Hz to 60 Hz, and the above cycle is repeated 1 to 6 times to obtain the fourth slurry solution, but the invention is not limited thereto. In another preferred embodiment, the pH adjusting solution comprises the organic acid and the inorganic acid in a molar ratio of 6:1, but the invention is not limited thereto. In another preferred embodiment, the pH value of the electrolyte slurry is 4.5 to 6.5, but the invention is not limited thereto.

[0052] The following provides the types of materials used in the first to seventh embodiments.

[0053] More preferably, the oxide solid electrolyte particles include one or more of, but not limited to, lithium lanthanum zirconium oxide (LLZO), lithium lanthanum zirconium tantalum oxide (LLZTO), lithium lanthanum zirconium germanium oxide (LLZGO), lithium lanthanum titanate oxide (LLTO), or lithium lanthanum zirconium aluminum oxide (LLZAO). Among them, lithium lanthanum titanate oxide (LLTO) is a perovskite-type, while the other oxide solid electrolyte particles are garnet-type.

[0054] More preferably, the oxide coating material comprises titanium dioxide (TiO2), tin dioxide (SnO2), aluminum oxide (Al2O3), copper oxide (CuO), silicon dioxide (SiO2), antimony trioxide (Sb2O3), lanthanum aluminate alumina (3LaAlO3·Al2O3), aluminum fluoride (AlF3), yttrium aluminate (Y3Al5O 12 ), lithium titanate (Li4Ti5O 12 ), vanadium pentoxide (V2O5), lithium manganate (LiMn2O4), lithium aluminate (LiAlO2), zirconium dioxide (ZrO2), magnesium oxide (MgO), or aluminum phosphate (AlO4P) One or more of, but not limited to.

[0055] More preferably, the first solvent, the second solvent, the third solvent, the fourth solvent, the fifth solvent, the sixth solvent, or the seventh solvent comprises one or more of, but not limited to, N-methylpyrrolidone (NMP), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), acetonitrile (ACN), acetone (ACE), methanol, ethanol, benzyl alcohol, ethylene glycol (EG), n-butanol, isopropyl alcohol (IPA), glycerol, or deionized water. In a preferred embodiment, any two of the first solvent, the second solvent, the third solvent, the fourth solvent, the fifth solvent, the sixth solvent, or the seventh solvent may be the same or different.

[0056] More preferably, the first dispersant or the second dispersant comprises an inorganic dispersant, including, but not limited to, one or more of silicates, sodium tripolyphosphate, sodium hexametaphosphate, sodium pyrophosphate, nitrates, sulfates, or hydroxyl compounds. In a preferred embodiment, the silicates comprise, but not limited to, one or more of sodium silicate, sodium metasilicate, calcium silicate, magnesium silicate, aluminum silicate, or water glass. In another preferred embodiment, the hydroxyl compound comprises, but not limited to, one or more of sodium hydroxide or potassium hydroxide.

[0057] More preferably, the first dispersant or the second dispersant comprises: an organic dispersant, including: one or more of sodium polyacrylate, polymethyl methacrylate, polyethyl methacrylate, sodium oleate, sodium formate, sodium acetate, sodium propionate, sodium stearate, fatty alcohol sulfate, secondary alkyl sulfate, lignin sulfonate, carboxymethyl cellulose and carboxymethyl cellulose sodium salt, petroleum sulfonate, alkylphenol ether sulfate, triethylhexyl phosphoric acid, sodium lauryl sulfate, methylpentyl alcohol, cellulose derivatives, polyacrylamide, guar gum, or fatty acid polyethylene glycol ester, but not limited thereto.

[0058] More preferably, the fluorine-containing polymer includes one or more of polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), polyvinyl fluoride (PVF), or ethylene-tetrafluoroethylene copolymer (ETFE), but is not limited thereto.

[0059] More preferably, the fluorine-free polymer includes one or more of, but is not limited to, polyethylene oxide (PEO), polyacrylonitrile (PAN), polyimide (PI), polyacrylic acid (PAA), polyethyleneimine (PEI), polyvinylpyrrolidone (PVP), polymethyl methacrylate (PMMA), polyamidoamine dendrimer (PAMAM), polyacrylamide (PAM), nanocellulose (CNF), or aramid (AF). In a preferred embodiment, the fluorine-free polymer is alkali-resistant, but is not limited to this.

[0060] More preferably, the organic acid comprises one or more of citric acid, L-ascorbic acid, malic acid, tartaric acid, acetic acid, oxalic acid, formic acid, benzoic acid, phenylacetic acid, trifluoroacetic acid, salicylic acid, succinic acid, adipic acid, lactic acid, pyruvic acid, acetoacetic acid, β-hydroxybutyric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, phthalic acid, terephthalic acid, oxaloacetic acid, amino acids, or nucleotides, but is not limited thereto.

[0061] More preferably, the inorganic acid comprises one or more of hydrochloric acid, nitric acid, boric acid, sulfuric acid, carbonic acid, phosphoric acid, hydrofluoric acid, nitrous acid, hypochlorous acid, silicic acid, pyrophosphoric acid, pyrosulfuric acid, or tetrahydroxyaluminic acid, but is not limited thereto.

[0062] More preferably, the alkali-resistant polymer includes one or more of a polyimide (PI) polymer, a polyethersulfone (PES) polymer, a fluorinated polyester (PFA) polymer, or a fluorinated polyetherketone (PEEK) polymer, but is not limited thereto.

[0063] More preferably, the buffered salt solution comprises one or more of ammonium sulfate, ammonium oxalate, or ammonium sulfite, but is not limited thereto.

[0064] More preferably, in the first to seventh embodiments, the stirring and mixing is performed at a rotation speed of 350 to 2100 rpm for 2 to 4 hours; or the ball milling is performed at a frequency of 32 Hz to 60 Hz, with forward and reverse ball milling for 10 to 60 minutes per cycle, and the above cycle is repeated 1 to 6 times.

[0065] The following provides Example 1 of the present invention.

[0066] First, 3 kg of lithium lanthanum zirconium oxide (LLZO), 15 g of SnO2, and 7 kg of isopropyl alcohol (IPA) were stirred and mixed to obtain a second slurry solution; then, the second slurry solution, 0.5 g of sodium metasilicate, and 3 g of sodium lauryl ether sulfate were mixed and ball-milled to obtain a mixed material; then, the mixed material was placed in a vacuum drying oven and dried at 180°C for 24 hours to obtain a dry material; next, the dry material was placed in a rotary kiln, protected by argon as the gas atmosphere, and sintered at 600°C to obtain an inorganic coated composite material.

[0067] Carboxymethyl cellulose, polymethyl methacrylate, and sodium silicate were stirred and mixed in a mass ratio of 60:5:1 to prepare a second dispersant; 2 kg of an inorganic coated composite material and 2.75 kg of N-methylpyrrolidone (NMP) were mixed and placed in a vacuum-sealed reactor. The mixture was stirred at 2100 rpm for 4 hours, and then 0.07 kg of the second dispersant was added. The mixture was stirred at 350 rpm for 2 hours to obtain a nano-dispersed slurry, wherein the particle size D50 of the solid particles contained in the nano-dispersed slurry was 500 nm.

[0068] 0.15 kg of PVDF-HFP and 1.5 kg of DMAc were thoroughly stirred and mixed in a vacuum-sealed reactor to obtain a completely clear and transparent polymer solution.

[0069] 0.75 kg of polymer glue was slowly added dropwise to 4.5 kg of the stirred nano-dispersed slurry to obtain a uniform and stable diaphragm slurry.

[0070] The separator slurry of Example 1 was micro-gravure coated on a polyolefin battery separator, with the coating thickness on one side controlled to be 1.5±0.2 μm. After being cut into the required width, it was used to make soft-pack batteries. The electrochemical properties of the obtained soft-pack batteries are summarized in the following Table 1.

[0071] The following provides Example 2 of the present invention.

[0072] First, 20 kg of lithium lanthanum zirconium oxide (LLZO) was mixed with 30 kg of a first solvent and stirred at 2000 rpm for 4 hours to uniformly disperse the LLZO in the first solvent, thereby obtaining a first slurry solution. Next, 2 kg of polyethylene oxide (PEO) was weighed and stirred with the first slurry solution to obtain an organic-coated composite material. In Example 2, functional groups in the polymer molecules were adsorbed on the alkaline outer layer of the LLZO structure and chemically reacted to coat the LLZO. This improved the surface properties of the LLZO powder and resulted in a uniform and stable organic-coated composite material.

[0073] The organic coating composite material of Example 2 was micro-gravure coated on a polyolefin battery separator, with the coating thickness on one side controlled to be 1.5±0.2 μm. After being cut into the required width, it was used to make soft-pack batteries. The electrochemical properties of the obtained soft-pack batteries are summarized in the following Table 1.

[0074] The following provides Example 3 of the present invention.

[0075] First, 0.015 kg of oxalic acid, 0.2 kg of modified polyimide polymer, and 2.5 kg of DMAc solvent were mixed and stirred thoroughly to obtain a mixed solution; then, the mixed solution was mixed with 3% ammonium sulfite at a mass ratio of 5:1 and stirred evenly to obtain a pretreatment solution with a concentration of 0.5%; then, 3.5 kg of PVDF-HFP polymer, 2.5 kg of PEO polymer, and 30 kg of DMAc solvent were stirred and mixed, and then 14 kg of lithium lanthanum zirconium oxide (LLZO) was added and mixed together to obtain an organic-coated composite material; finally, the pretreatment solution and the organic-coated composite material were stirred and mixed to obtain a diaphragm slurry.

[0076] The separator slurry of Example 3 was micro-gravure coated on a polyolefin battery separator, with the coating thickness on one side controlled to be 1.5±0.2 μm. After being cut into the required width, it was used to make soft-pack batteries. The electrochemical properties of the obtained soft-pack batteries are summarized in the following Table 1.

[0077] The following provides Example 4 of the present invention.

[0078] First, 5 kg of PVDF-HFP was stirred and mixed with 25 kg of DMF to obtain a polymer glue solution; then, 15 kg of lithium lanthanum zirconium oxide (LLZO) was mixed and dispersed with 60 kg of acetone solvent, filtered, and then dried at 110 ° C for more than 12 hours to remove the solvent and obtain an oxide solid electrolyte powder; then, the oxide solid electrolyte powder was mixed with 45 kg of DMF, ball milled at 48 Hz for 30 minutes each in a cycle, and repeated 4 times to obtain a fourth slurry solution; then, citric acid and dilute nitric acid were mixed in a molar ratio of 6:1 to obtain a pH regulating solution; then, the pH regulating solution was added to the fourth slurry solution to obtain an electrolyte slurry with a pH value of less than 6.3; finally, while the electrolyte slurry was dispersed and stirred, the polymer glue solution was slowly added dropwise to the electrolyte slurry to obtain a stable diaphragm slurry.

[0079] The separator slurry of Example 4 was micro-gravure coated on a polyolefin battery separator, with the coating thickness on one side controlled to be 1.5±0.2 μm. After being cut into the required width, it was used to make soft-pack batteries. The electrochemical properties of the obtained soft-pack batteries are summarized in the following Table 1.

[0080] The following provides Example 5 of the present invention.

[0081] First, 3 kg of lithium lanthanum zirconium tantalum oxide (LLZTO), 15 g of SnO2, and 7 kg of isopropyl alcohol (IPA) were stirred and mixed to obtain a second slurry solution; then, the second slurry solution, 0.5 g of sodium metasilicate, and 3 g of sodium lauryl ether sulfate were mixed and ball-milled to obtain a mixed material; then, the mixed material was placed in a vacuum drying oven and dried at 180°C for 24 hours to obtain a dry material; next, the dry material was placed in a rotary kiln, protected by argon as the gas atmosphere, and sintered at 600°C to obtain an inorganic coated composite material.

[0082] First, 2.5 kg of the inorganic coated composite material was dispersed in 7.5 kg of isopropyl alcohol (IPA). The mixture was then bidirectionally milled in a planetary ball mill at 48 Hz, with a 10-minute run followed by a 1-minute rest. This cycle was repeated 12 times. The mixture was then filtered thoroughly through a 300-mesh filter cloth using a high-pressure vacuum pump at 0.1 to 1 MPa to obtain a nanodispersed slurry. The particle size (D50) of the nanodispersed slurry was measured to be 500 nm.

[0083] 0.5 kg of polyethylene oxide (PEO) is uniformly stirred and mixed with the nano-dispersed slurry, and the functional groups in the polymer molecules are adsorbed on the outer layer of the alkaline oxide solid electrolyte structure and chemically reacted to perform coating modification, so as to improve the surface properties of the oxide solid electrolyte powder and obtain an organic-inorganic coated composite material.

[0084] The organic-inorganic coating composite material was micro-gravure coated on a polyolefin battery separator using a roller coater, with the coating thickness on one side controlled to be 1.5±0.2 μm. The separator was then cut into the required width and used to make soft-pack batteries. The electrochemical properties of the obtained soft-pack batteries are summarized in Table 1 below.

[0085] The following provides comparative example 1 of the present invention.

[0086] First, 15 kg of lithium lanthanum zirconium oxide (LLZO) was added to 25 kg of DMAc solvent and mixed uniformly to prepare a uniform slurry, wherein: the particle size D50 of the solid particles in the obtained uniform slurry was 500 nm; then, 3 kg of PVDF-HFP was thoroughly stirred and mixed with 30 kg of DMAc solvent until the polymer was completely dissolved to obtain a polymer solution; then, the polymer solution was slowly added to the uniformly stirred slurry to obtain a diaphragm slurry.

[0087] The separator slurry of Comparative Example 1 was micro-gravure coated on a polyolefin battery separator, with the coating thickness on one side controlled to be 1.5±0.2 μm. After being cut into the required width, it was used to make soft-pack batteries. The electrochemical properties of the obtained soft-pack batteries are summarized in the following Table 1.

[0088] The results in Table 1 indicate that, since the lithium lanthanum zirconium oxide (LLZO) was not modified in Comparative Example 1, the separator slurry prepared therein exhibited discoloration and gelation, similar to the prior art. This resulted in surface defects on the battery separator, further leading to unstable electrochemical performance of the battery. However, since the lithium lanthanum zirconium oxide (LLZO) was surface modified and coated in Examples 1 to 5, the separator slurry was prevented from deterioration and could be evenly and stably applied to the separator base film. Consequently, batteries fabricated using the separators of Examples 1 to 5 exhibited excellent electrochemical performance.

[0089] Table 1. Battery performance of batteries prepared in various examples and comparative examples

[0090]

[0091] The present invention is more effective than the prior art in that, in the prior art, the alkaline oxide solid electrolyte will discolor and gel after being mixed with the fluoropolymer, which makes it impossible to evenly and stably apply the slurry to the diaphragm base film. Since the membrane surface of the battery diaphragm obtained after applying the slurry contains obvious defects, the electrochemical performance of the battery made with the above-mentioned battery diaphragm is unstable. The diaphragm slurry prepared by the present invention can avoid the defects of the prior art. Specifically, the present invention modifies the raw materials by inorganic coating treatment or organic coating treatment to solve the problem of discoloration or gelation of the diaphragm slurry and obtain a stable diaphragm slurry. After the diaphragm slurry prepared by the present invention is applied to the base film, a solid electrolyte composite diaphragm with high ionic conductivity can be prepared, and when the battery is prepared with the diaphragm slurry, it can ensure that the battery has excellent electrochemical performance.

[0092] However, the above is only a preferred embodiment of the present invention, and it cannot be used to limit the scope of patent protection of the present invention; therefore, any simple equivalent changes and modifications made according to the scope of patent protection of the present invention and the contents of the specification still fall within the scope of patent protection of the present invention.

Claims

1. A diaphragm slurry, characterized in that: Include: a first slurry solution comprising: one or more of oxide solid electrolyte particles or nano-dispersed slurry, and a first solvent, wherein the first slurry solution has a solid content of 10 wt % to 70 wt %; and The non-fluorine-containing polymer has a solid mass ratio of the first slurry to the non-fluorine-containing polymer of 10:1 to 1:

3.

2. The diaphragm slurry according to claim 1, characterized in that The method further comprises a pretreatment solution, which comprises an organic acid, an alkali-resistant polymer, a second solvent, and a buffered salt solution.

3. The diaphragm slurry according to claim 2, characterized in that: The concentration of the pretreatment solution is 0.1 to 15%; The buffered saline solution comprises ammonium sulfite at a concentration of 3%; The mass ratio of the mixture of the organic acid, the alkali-resistant polymer, and the second solvent to the buffered saline solution is 10:1 to 1:50; or The mass ratio of the mixture of the organic acid, the alkali-resistant polymer and the second solvent to the buffered salt solution is 5:

1.

4. The diaphragm slurry according to claim 1, characterized in that It further comprises a polymer glue, which comprises a second fluorine-containing polymer and a third solvent.

5. The diaphragm slurry according to claim 1, characterized in that: The nano-dispersed slurry comprises: An inorganic coating composite material, a fifth solvent, and a second dispersant.

6. The diaphragm slurry according to claim 5, characterized in that: The inorganic coating composite material comprises oxide solid electrolyte particles and oxide coating material.

7. A diaphragm slurry, characterized in that: The invention comprises an inorganic coating composite material, a fifth solvent, and a second dispersant.

8. The diaphragm slurry according to claim 7, characterized in that: The inorganic coating composite material, the fifth solvent, and the second dispersant were stirred and mixed at a rotation speed of 350 rpm for 2 hours, and the particle size D50 of the solid particles contained in the diaphragm slurry was 500 nm.

9. The diaphragm slurry according to claim 7, characterized in that It further comprises: a pretreatment solution, and one or more of a fluorine-containing polymer or a fluorine-free polymer.

10. The diaphragm slurry according to claim 9, characterized in that The pretreatment solution comprises: An organic acid, an inorganic acid, an alkali-resistant polymer, a second solvent, and a buffered saline solution, wherein the weight ratio of a mixture of one or more of the organic acid, the inorganic acid, the alkali-resistant polymer, and the second solvent to the buffered saline solution is 10:1 to 1:

50.

11. The diaphragm slurry according to claim 10, characterized in that : The concentration of the pretreatment solution is 0.1 to 15%; The buffered saline solution comprises ammonium sulfite at a concentration of 3%; or The mass ratio of the mixture of the organic acid, the inorganic acid, the alkali-resistant polymer, and the second solvent to the buffered salt solution is 5:

1.

12. A diaphragm slurry, characterized in that: Contains: nano-dispersed slurry and polymer glue.

13. The diaphragm slurry according to claim 12, characterized in that The polymer glue comprises a second fluorine-containing polymer and a third solvent.

14. A diaphragm slurry, characterized in that: Contains: polymer glue, and electrolyte slurry.

15. The diaphragm slurry according to claim 14, characterized in that: The pH value of the electrolyte slurry is 4.5 to 6.5.

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