A high-voltage resistant polyurethane material for solid-state battery packaging and its preparation process

Abstract

The present invention provides a high-voltage-resistant polyurethane material for solid-state battery encapsulation and a preparation process thereof, belonging to the field of polymer materials. The preparation process comprises the following steps: preparing a nanofiller A; preparing a nanofiller B; preparing a coated modified composite filler; preparing a silicon-boron modifier; and synthesizing a polyurethane material. The present invention first prepares carbon-coated silicon powder using phenolic resin and silicon powder as raw materials, which is then composited with boron nitride nanosheets to form nanofiller A. Zinc oxide nanowires are then prepared by a hydrothermal reaction using zinc nitrate hexahydrate and sodium hydroxide as raw materials. These nanowires are then mixed with aluminum nitrate and sodium borohydride to form nanofiller B, which is a composite of nanoalumina particles and zinc oxide nanowires. The coated modified composite filler, formed by mixing nanofillers A and B, is added to a polyurethane material to synergistically improve the chemical corrosion resistance and electrical insulation properties of the polyurethane.

Description

Technical Field

[0001] The present invention relates to the field of polymer materials, and in particular to a high-pressure resistant polyurethane material for solid-state battery packaging and a preparation process thereof. Background Art

[0002] Solid-state batteries are a new energy storage technology with great potential. Compared with traditional liquid batteries, solid-state batteries have significant advantages such as higher energy density, better safety and longer service life. Therefore, they are widely considered to be one of the key technologies for future electric vehicles and large-scale energy storage systems. However, in the actual use of batteries, the packaging materials need to withstand complex and changeable chemical environments and high pressure conditions. On the one hand, the electrolyte and electrode materials inside the battery may chemically react with the packaging materials, resulting in performance degradation of the packaging materials, such as swelling, corrosion, and rupture. This will not only affect the battery packaging effect, but may also cause serious safety hazards such as internal short circuits and electrolyte leakage, greatly reducing the reliability and service life of the battery. On the other hand, solid-state batteries will produce a certain amount of gas during the charging and discharging process, causing the internal pressure of the battery to increase. The packaging material must have good high-pressure resistance to prevent the battery shell from deforming or even rupturing due to excessive pressure, thereby ensuring the structural integrity and safety of the battery.

[0003] At present, commonly used battery packaging materials include metal materials, ceramic materials and polymer materials. Although metal materials have high strength and good conductivity, they have poor corrosion resistance and are easily corroded by chemical substances inside the battery. In addition, they are heavy, which is not conducive to improving the energy density and lightweight design of the battery. Ceramic materials have excellent high temperature resistance and chemical stability, but they are relatively brittle and have poor processing performance. They are difficult to meet the packaging requirements of batteries with complex shapes and are also expensive. Polymer materials have become one of the research hotspots of battery packaging materials due to their advantages such as light weight, easy molding and processing, and relatively low cost. Polyurethane materials, as an important polymer material, have good flexibility, wear resistance, adhesion and mechanical properties, and have been widely used in many fields. However, ordinary polyurethane materials have deficiencies in chemical corrosion resistance and high voltage resistance, making them difficult to be directly applied to the packaging of solid-state batteries.

[0004] Therefore, it is necessary to develop a high-pressure resistant polyurethane material for solid-state battery packaging with excellent chemical corrosion resistance and its preparation process to extend its service life. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a high-pressure resistant polyurethane material for solid-state battery packaging and a preparation process thereof.

[0006] A process for preparing a high-pressure resistant polyurethane material for solid-state battery packaging comprises the following steps:

[0007] S1: Preparation of nanofiller A

[0008] Silicon powder is dispersed in a phenolic resin solution, centrifuged and heated to prepare carbon-coated silicon powder, which is then dispersed together with boron nitride nanosheets in anhydrous ethanol. After adding deionized water, the mixture is stirred, centrifuged, vacuum dried, and heat-treated to obtain nanofiller A.

[0009] S2: Preparation of nanofiller B

[0010] Dissolving zinc nitrate hexahydrate and sodium hydroxide separately, mixing them and performing a hydrothermal reaction to prepare zinc oxide nanowires, then dissolving aluminum nitrate and sodium borohydride and mixing them, adding the zinc oxide nanowires and reacting them to obtain nanofiller B;

[0011] S3: Preparation of coated modified composite fillers

[0012] The nanofiller A and the nanofiller B are dispersed in an ethanol solution, and then titanium sulfate solution and chitosan quaternary ammonium salt are added to react to obtain a coated modified composite filler;

[0013] S4: Preparation of silicon-boron modifier

[0014] Vinyltriethoxysilane, aminotriethoxysilane, phenyldiethoxysilane and HCl aqueous solution are mixed and heated to react, and then boric acid solution is added to continue the reaction to obtain a silicon boron modifier;

[0015] S5: Synthetic polyurethane material

[0016] Add polyol, isocyanate and dibutyltin dilaurate into a reactor, heat at 70-80°C for 2-4 hours, then add chain extender, the above-mentioned coated modified composite filler, the above-mentioned silicon boron modifier and tetrabutyl titanate, stir at 20-30°C for 1-2 hours, and obtain a polyurethane material by vacuum degassing and curing.

[0017] Furthermore, S1 specifically includes the following steps:

[0018] S1.1: Add phenolic resin to anhydrous ethanol at a solid-liquid ratio of 1 g:(20-30) mL. Heat and stir at 40-50°C for 1-2 h to fully dissolve the phenolic resin solution.

[0019] S1.2: Disperse silicon powder in the phenolic resin solution at a solid-liquid ratio of 1 g:(50-60) mL. Centrifuge at 5000-6000 rpm for 20-30 min to separate solid particles. Heat at 600-800°C for 3-4 h under a nitrogen atmosphere to obtain carbon-coated silicon powder.

[0020] S1.3: Add boron nitride nanosheets and the carbon-coated silicon powder to anhydrous ethanol at a solid-liquid ratio of 1 g:(3-5) g:(50-60) mL. Ultrasonicate for 10-20 min. Heat and stir at 40-50°C for 2-3 h to obtain a mixed precursor solution.

[0021] S1.4: Add the above mixed precursor solution to deionized water in a volume ratio of 1:(1.5-2.5), continue stirring for 1-2 hours, centrifuge and vacuum dry at 60-80℃ for 8-10 hours, heat grind at 700-800℃ for 2-3 hours, and then heat treat at 1500-1600℃ for 1-2 hours to obtain nanofiller A.

[0022] Furthermore, S2 specifically includes the following steps:

[0023] S2.1: Dissolve zinc nitrate hexahydrate and sodium hydroxide in deionized water at a solid-liquid ratio of 1 g:(40-50) mL to obtain zinc nitrate solution and sodium hydroxide solution, respectively.

[0024] S2.2: Stir and mix equal volumes of the zinc nitrate solution and the sodium hydroxide solution, transfer the mixture to a hydrothermal reactor, and heat at 175-185°C for 8-10 hours. After washing and drying, zinc oxide nanowires are obtained.

[0025] S2.3: Dissolve aluminum nitrate and sodium borohydride in deionized water at a solid-liquid ratio of 1g:(0.02-0.03)g:(80-90)mL and stir thoroughly. Then add the above-mentioned zinc oxide nanowires at a solid-liquid ratio of 1g:(140-150)mL and stir for 2-3h. After filtering, washing, and drying, nanofiller B is obtained.

[0026] Furthermore, S3 specifically includes the following steps:

[0027] S3.1: Add titanium sulfate powder to 1 wt% acetic acid solution at a solid-to-liquid ratio of 1 g:(70-80) mL and stir thoroughly to dissolve to obtain a titanium sulfate solution.

[0028] S3.2: Add nanofiller A prepared in step S1.4 and nanofiller B prepared in step S2.3 to 50% ethanol solution at a solid-liquid ratio of 1 g:(1-3) g:(100-120) mL and ultrasonically disperse for 1-2 h to obtain a binary suspension;

[0029] S3.3: Add the titanium sulfate solution to the binary suspension, disperse by ultrasonication for 10-20 minutes, and then heat and stir at 75-85°C for 1-2 hours to obtain a ternary suspension.

[0030] S3.4: Add chitosan quaternary ammonium salt to the above ternary suspension, continue stirring for 4-5 hours to react, and obtain a coated modified composite filler through centrifugation, washing, drying and grinding.

[0031] Furthermore, S4 specifically includes the following steps:

[0032] S4.1: Add boric acid to anhydrous ethanol at a solid-to-liquid ratio of 1 g:(30-40) mL and stir thoroughly to obtain a boric acid solution.

[0033] S4.2: Stir vinyltriethoxysilane, aminotriethoxysilane, and phenyldiethoxysilane in a mass ratio of 1:(1-3):(1-3) at a rate of 200-300 r / min and heat to 70-80°C, then add aqueous HCl solution while stirring, and keep the mixture for 1-2 hours to obtain a precursor mixture;

[0034] S4.3: Add the above boric acid solution to the above precursor mixture and continue the reaction for 3-4 hours. After removing impurities by vacuum distillation, a silicon boron modifier is obtained.

[0035] Furthermore, the mass ratio of titanium sulfate to the total amount of nanofiller A and nanofiller B is (1.5-2.5):1, and the mass ratio of chitosan quaternary ammonium salt to the total amount of nanofiller A and nanofiller B is (3-4):1.

[0036] Furthermore, the volume ratio of the HCl aqueous solution to the total amount of vinyltriethoxysilane, aminotriethoxysilane and phenyldiethoxysilane is 1:(12-14), and the HCl aqueous solution is a (2-3) mol / L hydrochloric acid solution.

[0037] Furthermore, the polyol is one or more of polysiloxane polyol, polyether polyol or polyester polyol, the isocyanate is one or more of diphenylmethane diisocyanate and hexamethylene diisocyanate, and the chain extender is one or more of ethylene glycol and diethylene glycol.

[0038] Furthermore, the raw material components of the polyurethane material include, by mass: 40-50 parts of polyol, 35-45 parts of isocyanate, 0.2-0.4 parts of dibutyltin dilaurate, 2-4 parts of chain extender, 13-15 parts of coated modified composite filler, 15-20 parts of silicon boron modifier and 0.8-1.2 parts of tetrabutyl titanate.

[0039] Furthermore, a high-pressure-resistant polyurethane material for solid-state battery encapsulation is prepared by the preparation process of a high-pressure-resistant polyurethane material for solid-state battery encapsulation described in any of the above items.

[0040] Compared with the prior art, the present invention has at least the following beneficial effects:

[0041] 1. The present invention first prepares carbon-coated silicon powder using phenolic resin and silicon powder as raw materials, and then composites it with boron nitride nanosheets to form nanofiller A. Then, zinc oxide nanowires are prepared by hydrothermal reaction using zinc nitrate hexahydrate and sodium hydroxide as raw materials, and the prepared nanofiller B is mixed with aluminum nitrate and sodium borohydride to form nanofiller B, which is a composite of nanoalumina particles and zinc oxide nanowires. After the coated modified composite filler prepared by mixing nanofiller A and nanofiller B is added to a polyurethane material, the nanofillers A and nanofillers B jointly form a multi-layered physical barrier, reducing the contact opportunity between corrosive substances and polyurethane molecules, thereby synergistically improving the chemical corrosion resistance of the polyurethane. Furthermore, since nanofillers A and nanofillers B themselves have good insulating properties, they can make the migration path of carriers in the polyurethane matrix tortuous, increase the probability of carrier scattering, and thus reduce the carrier mobility, thereby synergistically improving the electrical insulation of the polyurethane and further improving its high-voltage resistance.

[0042] 2. The present invention first disperses nanofiller A and nanofiller B in an ethanol solution, then adds an aqueous solution of titanium sulfate and chitosan quaternary ammonium salt to react, and uses titanium sulfate as a cross-linking agent to coat the chitosan quaternary ammonium salt on the surfaces of nanofiller A and nanofiller B to form a steric hindrance layer, thereby preventing direct contact and interaction between the nanofillers, thereby reducing their agglomeration in the polyurethane, and maintaining a good dispersion state in the polyurethane, thereby achieving the effect of improving the dispersibility of nanofiller A and nanofiller B, and further improving the chemical corrosion resistance and electrical insulation properties of the prepared polyurethane.

[0043] 3. The present invention prepares a silicon boron modifier by first using vinyl triethoxysilane, amino triethoxysilane, phenyl diethoxysilane and boric acid as raw materials, wherein boron is doped into the organic silicon molecule in the form of BO-Si. Then, under the catalysis of tetrabutyl titanate, the silicon boron modifier is reacted with a polyurethane prepolymer to modify the polyurethane material. Due to the high bond energy of BO-Si in the silicon boron modifier, an inorganic thermal insulation layer containing Si-O-Si and BO-Si can be formed on the surface of the polyurethane material at high temperature, protecting the polyurethane material matrix from being destroyed by thermal shock, thereby effectively improving the thermal stability of the polyurethane material. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The accompanying drawings, which are incorporated herein and constitute a part of the specification, illustrate embodiments of the present disclosure and, together with the description, further serve to explain the principles of the present disclosure and to enable one skilled in the relevant art to make and use the present disclosure.

[0045] Figure 1 This is a flow chart of the preparation process of the high-pressure resistant polyurethane material for solid-state battery packaging used in an embodiment of the present invention.

[0046] Figure 2 This is the SEM image of filler A prepared in Example 1 of the present invention.

[0047] Figure 3 This is the SEM image of filler B prepared in Example 1 of the present invention.

[0048] Figure 4 This is the infrared spectrum of the silicon-boron modifier prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0049] The following describes in detail a high-pressure resistant polyurethane material for solid-state battery packaging and its preparation process provided by the present invention in conjunction with the accompanying drawings and specific embodiments. Example

[0050] A preparation process of high-pressure resistant polyurethane material for solid-state battery packaging, such as Figure 1 As shown, the following steps are included:

[0051] S1: Preparation of nanofiller A

[0052] S1.1: Add phenolic resin to anhydrous ethanol at a solid-liquid ratio of 1 g:20 mL. Heat and stir at 40°C for 1 h to fully dissolve the phenolic resin solution.

[0053] S1.2: Disperse silicon powder in the phenolic resin solution at a solid-liquid ratio of 1 g:50 mL. Centrifuge the solution at 5000 rpm for 20 min to separate the solid particles. Then, heat the solution at 600°C for 3 h under a nitrogen atmosphere to obtain carbon-coated silicon powder.

[0054] S1.3: Add boron nitride nanosheets and the carbon-coated silicon powder to anhydrous ethanol at a solid-liquid ratio of 1 g:3 g:50 mL. Ultrasonicate for 10 min, then heat and stir at 40°C for 2 h to obtain a mixed precursor solution.

[0055] S1.4: The mixed precursor solution was added to deionized water at a volume ratio of 1:1.5, and the mixture was stirred for 1 hour. After centrifugation and vacuum drying at 60°C for 8 hours, the mixture was heated and ground at 700°C for 2 hours, and then heat-treated at 1500°C for 1 hour to obtain nanofiller A. The SEM image of the nanofiller is shown in FIG. Figure 2 As shown;

[0056] S2: Preparation of nanofiller B

[0057] S2.1: Dissolve zinc nitrate hexahydrate and sodium hydroxide in deionized water at a solid-liquid ratio of 1 g:40 mL to obtain a zinc nitrate solution and a sodium hydroxide solution, respectively.

[0058] S2.2: Equal volumes of the zinc nitrate solution and the sodium hydroxide solution were stirred and mixed, and the mixture was transferred to a hydrothermal reactor. The mixture was heated at 175°C for 8 h, and then washed and dried to obtain zinc oxide nanowires.

[0059] S2.3: Aluminum nitrate and sodium borohydride were dissolved in deionized water at a solid-liquid ratio of 1g:0.02g:80mL, and the mixture was thoroughly stirred. Then, the zinc oxide nanowires were added at a solid-liquid ratio of 1g:140mL, and the mixture was stirred for 2h. After filtration, washing, and drying, the nanofiller B was obtained. The SEM image of the nanofiller B is shown in FIG. Figure 3 As shown;

[0060] S3: Preparation of coated modified composite fillers

[0061] S3.1: Add titanium sulfate powder to 1 wt% acetic acid solution at a solid-liquid ratio of 1 g:70 mL and stir thoroughly to dissolve to obtain a titanium sulfate solution.

[0062] S3.2: Add nanofiller A prepared in step S1.4 and nanofiller B prepared in step S2.3 to 50% ethanol solution at a solid-liquid ratio of 1 g:1 g:100 mL, and ultrasonically disperse for 1 h to obtain a binary suspension;

[0063] S3.3: Add the titanium sulfate solution to the binary suspension, ultrasonically disperse for 10 minutes, and then heat and stir at 75°C for 1 hour to obtain a ternary suspension, wherein the mass ratio of titanium sulfate to the total amount of nanofiller A and nanofiller B is 1.5:1;

[0064] S3.4: Add chitosan quaternary ammonium salt to the above ternary suspension, continue stirring for 4 hours to react, and obtain a coated modified composite filler by centrifugation, washing, drying, and grinding, wherein the mass ratio of chitosan quaternary ammonium salt to the total amount of nanofiller A and nanofiller B is 3:1;

[0065] S4: Preparation of silicon-boron modifier

[0066] S4.1: Add boric acid to anhydrous ethanol at a solid-liquid ratio of 1 g:30 mL and stir thoroughly to obtain a boric acid solution.

[0067] S4.2: Vinyltriethoxysilane, aminotriethoxysilane, and phenyldiethoxysilane in a mass ratio of 1:1:1 are stirred at a rate of 200 r / min and heated to 70°C, and then an aqueous HCl solution is added with stirring. The mixture is kept warm for 1 hour to obtain a precursor mixture, wherein the volume ratio of the aqueous HCl solution to the total amount of vinyltriethoxysilane, aminotriethoxysilane, and phenyldiethoxysilane is 1:12, and the aqueous HCl solution is a 2 mol / L hydrochloric acid solution;

[0068] S4.3: Add the boric acid solution to the precursor mixture and continue the reaction for 3 hours. After removing impurities by vacuum distillation, a silicon boron modifier is obtained;

[0069] S5: Synthetic polyurethane material

[0070] 40 parts by mass of polysiloxane polyol, 35 parts by mass of diphenylmethane diisocyanate and 0.2 parts by mass of dibutyltin dilaurate were added to a reactor and heated at 70°C for 2 hours. Then, 2 parts by mass of ethylene glycol, 13 parts by mass of the above-mentioned coated modified composite filler, 15 parts by mass of the above-mentioned silicon boron modifier and 0.8 parts by mass of tetrabutyl titanate were added, and the mixture was stirred at 20°C for 1 hour. After vacuum degassing and curing, a polyurethane material was obtained. Example

[0071] A preparation process of high-pressure resistant polyurethane material for solid-state battery packaging, such as Figure 1 As shown, the following steps are included:

[0072] S1: Preparation of nanofiller A

[0073] S1.1: Add phenolic resin to anhydrous ethanol at a solid-liquid ratio of 1 g:25 mL. Heat and stir at 45°C for 1.5 h to fully dissolve the phenolic resin solution.

[0074] S1.2: Disperse silicon powder in the phenolic resin solution at a solid-liquid ratio of 1 g:55 mL. Centrifuge at 5500 rpm for 25 min to separate solid particles. Heat at 700°C for 3.5 h under a nitrogen atmosphere to obtain carbon-coated silicon powder.

[0075] S1.3: Add boron nitride nanosheets and the carbon-coated silicon powder to anhydrous ethanol at a solid-liquid ratio of 1 g:4 g:55 mL. Ultrasonicate for 15 min, then heat and stir at 45°C for 2.5 h to obtain a mixed precursor solution.

[0076] S1.4: The mixed precursor solution was added to deionized water at a volume ratio of 1:2 and stirred for 1.5 h. After centrifugation and vacuum drying at 70°C for 9 h, the mixture was heated and ground at 750°C for 2.5 h, and then heat-treated at 1550°C for 1.5 h to obtain nanofiller A.

[0077] S2: Preparation of nanofiller B

[0078] S2.1: Dissolve zinc nitrate hexahydrate and sodium hydroxide in deionized water at a solid-liquid ratio of 1 g:45 mL to obtain a zinc nitrate solution and a sodium hydroxide solution, respectively.

[0079] S2.2: Equal volumes of the zinc nitrate solution and the sodium hydroxide solution were stirred and mixed, and the mixture was transferred to a hydrothermal reactor. The mixture was heated at 180°C for 9 h, and then washed and dried to obtain zinc oxide nanowires.

[0080] S2.3: Dissolve aluminum nitrate and sodium borohydride in deionized water at a solid-liquid ratio of 1 g:0.025 g:85 mL, stir thoroughly, then add the zinc oxide nanowires at a solid-liquid ratio of 1 g:145 mL. Stir and react for 2.5 h. Filter, wash, and dry to obtain nanofiller B.

[0081] S3: Preparation of coated modified composite fillers

[0082] S3.1: Add titanium sulfate powder to 1 wt% acetic acid solution at a solid-liquid ratio of 1 g:75 mL and stir thoroughly to dissolve to obtain a titanium sulfate solution.

[0083] S3.2: Add nanofiller A prepared in step S1.4 and nanofiller B prepared in step S2.3 to 50% ethanol solution at a solid-liquid ratio of 1 g:2 g:110 mL and ultrasonically disperse for 1.5 h to obtain a binary suspension;

[0084] S3.3: Add the titanium sulfate solution to the binary suspension, ultrasonically disperse for 15 minutes, and then heat and stir at 80°C for 1.5 hours to obtain a ternary suspension, wherein the mass ratio of titanium sulfate to the total amount of nanofiller A and nanofiller B is 2:1;

[0085] S3.4: Add chitosan quaternary ammonium salt to the above ternary suspension, continue stirring for 4.5 hours to react, and obtain a coated modified composite filler by centrifugation, washing, drying, and grinding, wherein the mass ratio of chitosan quaternary ammonium salt to the total amount of nanofiller A and nanofiller B is 3.5:1;

[0086] S4: Preparation of silicon-boron modifier

[0087] S4.1: Add boric acid to anhydrous ethanol at a solid-liquid ratio of 1 g:35 mL and stir thoroughly to obtain a boric acid solution.

[0088] S4.2: Vinyltriethoxysilane, aminotriethoxysilane, and phenyldiethoxysilane in a mass ratio of 1:2:2 are stirred at a rate of 250 r / min and heated to 75°C, and then an aqueous HCl solution is added with stirring. The mixture is kept warm for 1.5 hours to obtain a precursor mixture, wherein the volume ratio of the aqueous HCl solution to the total amount of vinyltriethoxysilane, aminotriethoxysilane, and phenyldiethoxysilane is 1:13, and the aqueous HCl solution is a 2.5 mol / L hydrochloric acid solution;

[0089] S4.3: Add the boric acid solution to the precursor mixture and continue the reaction for 3.5 hours. After removing impurities by vacuum distillation, a silicon boron modifier is obtained;

[0090] S5: Synthetic polyurethane material

[0091] 45 parts by mass of polyether polyol, 40 parts by mass of hexamethylene diisocyanate and 0.3 parts by mass of dibutyltin dilaurate were added to a reactor and heated at 75°C for 3 hours. Then, 3 parts by mass of diethylene glycol, 14 parts by mass of the above-mentioned coated modified composite filler, 17 parts by mass of the above-mentioned silicon boron modifier and 1 part by mass of tetrabutyl titanate were added, and the mixture was stirred at 25°C for 1.5 hours. After vacuum degassing and curing, a polyurethane material was obtained. Example

[0092] A preparation process of high-pressure resistant polyurethane material for solid-state battery packaging, such as Figure 1 As shown, the following steps are included:

[0093] S1: Preparation of nanofiller A

[0094] S1.1: Add phenolic resin to anhydrous ethanol at a solid-liquid ratio of 1 g:30 mL. Heat and stir at 40-50°C for 2 h to fully dissolve the phenolic resin solution.

[0095] S1.2: Disperse silicon powder in the phenolic resin solution at a solid-liquid ratio of 1 g:60 mL. Centrifuge the solution at 6000 rpm for 30 min to separate the solid particles. Then, heat the solution at 800°C for 4 h under a nitrogen atmosphere to obtain carbon-coated silicon powder.

[0096] S1.3: Add boron nitride nanosheets and the carbon-coated silicon powder to anhydrous ethanol at a solid-liquid ratio of 1 g:5 g:60 mL. Ultrasonicate for 20 min, then heat and stir at 50°C for 3 h to obtain a mixed precursor solution.

[0097] S1.4: The mixed precursor solution was added to deionized water at a volume ratio of 1:2.5 and stirred for 2 h. After centrifugation and vacuum drying at 80°C for 10 h, the mixture was heated and ground at 800°C for 3 h, and then heat-treated at 1600°C for 2 h to obtain nanofiller A.

[0098] S2: Preparation of nanofiller B

[0099] S2.1: Dissolve zinc nitrate hexahydrate and sodium hydroxide in deionized water at a solid-liquid ratio of 1 g:50 mL to obtain a zinc nitrate solution and a sodium hydroxide solution, respectively.

[0100] S2.2: Equal volumes of the zinc nitrate solution and the sodium hydroxide solution were stirred and mixed, and the mixture was transferred to a hydrothermal reactor. The mixture was heated at 185°C for 10 h. After washing and drying, zinc oxide nanowires were obtained.

[0101] S2.3: Dissolve aluminum nitrate and sodium borohydride in deionized water at a solid-liquid ratio of 1 g:0.03 g:90 mL and stir thoroughly. Then add the zinc oxide nanowires at a solid-liquid ratio of 1 g:150 mL and stir for 3 h. Filter, wash, and dry to obtain nanofiller B.

[0102] S3: Preparation of coated modified composite fillers

[0103] S3.1: Add titanium sulfate powder to 1 wt% acetic acid solution at a solid-liquid ratio of 1 g:80 mL and stir thoroughly to dissolve to obtain a titanium sulfate solution.

[0104] S3.2: Add nanofiller A prepared in step S1.4 and nanofiller B prepared in step S2.3 to 50% ethanol solution at a solid-liquid ratio of 1 g:3 g:120 mL and ultrasonically disperse for 2 h to obtain a binary suspension;

[0105] S3.3: Add the titanium sulfate solution to the binary suspension, ultrasonically disperse for 20 minutes, and then heat and stir at 85°C for 2 hours to obtain a ternary suspension, wherein the mass ratio of titanium sulfate to the total amount of nanofiller A and nanofiller B is 2.5:1;

[0106] S3.4: Add chitosan quaternary ammonium salt to the above ternary suspension, continue stirring for 5 hours to react, and obtain a coated modified composite filler by centrifugation, washing, drying, and grinding, wherein the mass ratio of chitosan quaternary ammonium salt to the total amount of nanofiller A and nanofiller B is 4:1;

[0107] S4: Preparation of silicon-boron modifier

[0108] S4.1: Add boric acid to anhydrous ethanol at a solid-liquid ratio of 1 g:40 mL and stir thoroughly to obtain a boric acid solution.

[0109] S4.2: Vinyltriethoxysilane, aminotriethoxysilane, and phenyldiethoxysilane in a mass ratio of 1:3:3 are stirred at a rate of 300 r / min and heated to 80°C, and then an aqueous HCl solution is added with stirring. The mixture is kept warm for 2 h to obtain a precursor mixture, wherein the volume ratio of the aqueous HCl solution to the total amount of vinyltriethoxysilane, aminotriethoxysilane, and phenyldiethoxysilane is 1:14, and the aqueous HCl solution is a 3 mol / L hydrochloric acid solution;

[0110] S4.3: Add the boric acid solution to the precursor mixture and continue the reaction for 4 hours. After removing impurities by vacuum distillation, a silicon boron modifier is obtained;

[0111] S5: Synthetic polyurethane material

[0112] 50 parts by mass of polysiloxane polyol, 45 parts by mass of hexamethylene diisocyanate and 0.4 parts by mass of dibutyltin dilaurate were added to a reactor and heated at 80°C for 4 hours. Then, 4 parts by mass of diethylene glycol, 15 parts by mass of the above-mentioned coated modified composite filler, 20 parts by mass of the above-mentioned silicon boron modifier and 1.2 parts by mass of tetrabutyl titanate were added, and the mixture was stirred at 30°C for 2 hours. After vacuum degassing and curing, a polyurethane material was obtained.

[0113] Comparative Example 1

[0114] The difference between Comparative Example 1 and Example 1 is that the nanofiller A in step S3.2 is replaced by an equal amount of nanofiller B.

[0115] Comparative Example 2

[0116] The difference between Comparative Example 2 and Example 1 is that the nanofiller B in step S3.2 is replaced by an equal amount of nanofiller A.

[0117] Comparative Example 3

[0118] The difference between Comparative Example 3 and Example 1 is that step S3 is removed, and nanofiller A and nanofiller B are directly added into the reactor in a mass ratio of 1:1 to prepare the polyurethane material.

[0119] Comparative Example 4

[0120] The difference between Comparative Example 4 and Example 1 is that the silicon-boron modifier in step S5 is removed.

[0121] Test Case

[0122] Test 1: The chemical corrosion resistance of the polyurethane materials prepared in Examples 1-3 and Comparative Examples 1-3 was tested. The polyurethane materials were immersed in a 5% by mass sodium hydroxide solution at 28°C for 48 hours, and the corrosion of the polyurethane materials was analyzed. The results are shown in Table 1.

[0123] Test 2: The surface resistivity and volume resistivity of the polyurethane materials prepared in Examples 1-3 and Comparative Examples 1-3 were tested. The results are shown in Table 1.

[0124] Table 1: Comparison of polyurethane material corrosion and insulation test results

[0125] Corrosion conditions Surface resistivity / Ω Volume resistivity / Ω·cm Example 1 No abnormalities <![CDATA[5.68×10 15 ]]> <![CDATA[5.56×10 15 ]]> Example 2 No abnormalities <![CDATA[5.72×10 15 ]]> <![CDATA[5.63×10 15 ]]> Example 3 No abnormalities <![CDATA[5.71×10 15 ]]> <![CDATA[5.49×10 15 ]]> Comparative Example 1 Spots appear <![CDATA[4.85×10 14 ]]> <![CDATA[3.89×10 14 ]]> Comparative Example 2 Spots appear <![CDATA[4.21×10 14 ]]> <![CDATA[3.65×10 14 ]]> Comparative Example 3 Discoloration <![CDATA[7.82×10 13 ]]> <![CDATA[7.96×10 13 ]]>

[0126] As can be seen from Table 1, the polyurethane materials prepared using single nanofiller B and single nanofiller A in Comparative Examples 1 and 2 showed spots after being immersed in sodium hydroxide solution for 48 hours, while the polyurethane materials prepared using nanofiller A and nanofiller B in Examples 1-3 showed no abnormalities, indicating that nanofiller A and nanofiller B have a synergistic effect of improving the chemical corrosion resistance of the polyurethane material. In addition, the surface resistivity and volume resistivity of the polyurethane materials prepared in Comparative Examples 1 and 2 are both lower than those in Examples 1-3, indicating that nanofiller A and nanofiller B also have a synergistic effect of improving the insulation properties of the polyurethane material.

[0127] However, after being corroded by sodium hydroxide solution for 48 hours, the polyurethane material prepared in Comparative Example 3 showed spots and discoloration, and its surface resistivity and volume resistivity were also lower than those of Examples 1-3. This shows that by first dispersing nanofiller A and nanofiller B in an ethanol solution, then adding an aqueous solution of titanium sulfate and chitosan quaternary ammonium salt to react, and using titanium sulfate as a cross-linking agent to coat the chitosan quaternary ammonium salt on the surfaces of nanofiller A and nanofiller B, the dispersibility of nanofiller A and nanofiller B can be improved, thereby further improving the chemical corrosion resistance and electrical insulation properties of the obtained polyurethane.

[0128] Test 3: The silicon boron modifier prepared in Example 1 was characterized by infrared spectroscopy. Figure 4 As shown; the temperature at which the mass loss of the polyurethane materials obtained in Examples 1-3 and Comparative Example 4 was 5% was tested by a thermogravimetric analyzer. The test conditions were: the mass of the polyurethane material was 10 mg and it was heated to 800°C in an air atmosphere. The results are shown in Table 2.

[0129] Table 2: Comparison of polyurethane material thermal stability test results

[0130] Example 1 Example 2 Example 3 Comparative Example 4 Temperature at which mass loss reaches 5% (°C) 302.87 304.16 305.21 268.42

[0131] like Figure 4 As shown, the silicon boron modifier is at 1343 cm -1 The absorption peak at 1262 cm is the stretching vibration peak of BO, -1 The absorption peak at 695 cm is the stretching vibration peak of Si-C. -1 The absorption peak at is the BO-Si in-plane shear vibration peak. In summary, boron is doped into the organosilicon molecule in the form of BO-Si.

[0132] In addition, it can be seen from Table 2 that when the silicon boron modifier is not used for modification in Comparative Example 4, the temperature at which the mass loss of the obtained polyurethane material is 5% is about 268.42° C., which is lower than that of Examples 1-3. Therefore, by first preparing the silicon boron modifier using vinyl triethoxysilane, amino triethoxysilane, phenyl diethoxysilane and boric acid as raw materials, and then reacting the silicon boron modifier with the polyurethane prepolymer under the catalysis of tetrabutyl titanate to modify the polyurethane material, the thermal stability of the polyurethane material can be improved.

[0133] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A process for preparing a high-pressure resistant polyurethane material for solid-state battery packaging, characterized in that: The steps include: S1: Preparation of nanofiller A Silicon powder is dispersed in a phenolic resin solution, centrifuged and heated to prepare carbon-coated silicon powder, which is then dispersed together with boron nitride nanosheets in anhydrous ethanol. After adding deionized water, the mixture is stirred, centrifuged, vacuum dried, and heat-treated to obtain nanofiller A. S2: Preparation of nanofiller B Dissolving zinc nitrate hexahydrate and sodium hydroxide separately, mixing them and performing a hydrothermal reaction to prepare zinc oxide nanowires, then dissolving aluminum nitrate and sodium borohydride and mixing them, adding the zinc oxide nanowires and reacting them to obtain nanofiller B; S3: Preparation of coated modified composite fillers The nanofiller A and the nanofiller B are dispersed in an ethanol solution, and then titanium sulfate solution and chitosan quaternary ammonium salt are added to react to obtain a coated modified composite filler; S4: Preparation of silicon-boron modifier Vinyltriethoxysilane, aminotriethoxysilane, phenyldiethoxysilane and HCl aqueous solution are mixed and heated to react, and then boric acid solution is added to continue the reaction to obtain a silicon boron modifier; S5: Synthetic polyurethane material Add polyol, isocyanate and dibutyltin dilaurate into a reactor, heat at 70-80°C for 2-4 hours, then add chain extender, the above-mentioned coated modified composite filler, the above-mentioned silicon boron modifier and tetrabutyl titanate, stir at 20-30°C for 1-2 hours, and vacuum degas and cure to obtain a polyurethane material; The polyol is one or more of polysiloxane polyol, polyether polyol or polyester polyol, the isocyanate is one or more of diphenylmethane diisocyanate and hexamethylene diisocyanate, and the chain extender is one or more of ethylene glycol and diethylene glycol.

2. The process for preparing a high-pressure resistant polyurethane material for solid-state battery packaging according to claim 1, characterized in that: S1 includes the following steps: S1.1: Add phenolic resin to anhydrous ethanol at a solid-liquid ratio of 1 g:(20-30) mL. Heat and stir at 40-50°C for 1-2 h to fully dissolve the phenolic resin solution. S1.2: Disperse silicon powder in the phenolic resin solution at a solid-liquid ratio of 1 g:(50-60) mL. Centrifuge at 5000-6000 rpm for 20-30 min to separate solid particles. Heat at 600-800°C for 3-4 h under a nitrogen atmosphere to obtain carbon-coated silicon powder. S1.3: Add boron nitride nanosheets and the carbon-coated silicon powder to anhydrous ethanol at a solid-liquid ratio of 1 g:(3-5) g:(50-60) mL. Ultrasonicate for 10-20 min. Heat and stir at 40-50°C for 2-3 h to obtain a mixed precursor solution. S1.4: Add the above mixed precursor solution to deionized water in a volume ratio of 1:(1.5-2.5), continue stirring for 1-2 hours, centrifuge and vacuum dry at 60-80℃ for 8-10 hours, heat grind at 700-800℃ for 2-3 hours, and then heat treat at 1500-1600℃ for 1-2 hours to obtain nanofiller A.

3. The process for preparing a high-pressure resistant polyurethane material for solid-state battery packaging according to claim 2, characterized in that: S2 includes the following steps: S2.1: Dissolve zinc nitrate hexahydrate and sodium hydroxide in deionized water at a solid-liquid ratio of 1 g:(40-50) mL to obtain zinc nitrate solution and sodium hydroxide solution, respectively. S2.2: Stir and mix equal volumes of the zinc nitrate solution and the sodium hydroxide solution, transfer the mixture to a hydrothermal reactor, and heat at 175-185°C for 8-10 hours. After washing and drying, zinc oxide nanowires are obtained. S2.3: Dissolve aluminum nitrate and sodium borohydride in deionized water at a solid-liquid ratio of 1g:(0.02-0.03)g:(80-90)mL and stir thoroughly. Then add the above-mentioned zinc oxide nanowires at a solid-liquid ratio of 1g:(140-150)mL and stir for 2-3h. After filtering, washing, and drying, nanofiller B is obtained.

4. The process for preparing a high-pressure resistant polyurethane material for solid-state battery packaging according to claim 3, characterized in that: S3 includes the following steps: S3.1: Add titanium sulfate powder to 1 wt% acetic acid solution at a solid-liquid ratio of 1 g:(70-80) mL and stir thoroughly to dissolve to obtain a titanium sulfate solution. S3.2: Add nanofiller A prepared in step S1.4 and nanofiller B prepared in step S2.3 to 50% ethanol solution at a solid-liquid ratio of 1 g:(1-3) g:(100-120) mL and ultrasonically disperse for 1-2 h to obtain a binary suspension; S3.3: Add the titanium sulfate solution to the binary suspension, disperse by ultrasonication for 10-20 minutes, and then heat and stir at 75-85°C for 1-2 hours to obtain a ternary suspension. S3.4: Add chitosan quaternary ammonium salt to the above ternary suspension, continue stirring for 4-5 hours to react, and obtain a coated modified composite filler through centrifugation, washing, drying and grinding.

5. The process for preparing a high-pressure resistant polyurethane material for solid-state battery packaging according to claim 4, characterized in that: S4 specifically includes the following steps: S4.1: Add boric acid to anhydrous ethanol at a solid-to-liquid ratio of 1 g:(30-40) mL and stir thoroughly to obtain a boric acid solution. S4.2: Stir vinyltriethoxysilane, aminotriethoxysilane, and phenyldiethoxysilane in a mass ratio of 1:(1-3):(1-3) at a rate of 200-300 r / min and heat to 70-80°C, then add aqueous HCl solution while stirring, and keep the mixture for 1-2 hours to obtain a precursor mixture; S4.3: Add the above boric acid solution to the above precursor mixture and continue the reaction for 3-4 hours. After removing impurities by vacuum distillation, a silicon boron modifier is obtained.

6. The process for preparing a high-pressure resistant polyurethane material for solid-state battery packaging according to claim 4, characterized in that: The mass ratio of titanium sulfate to the total amount of nanofiller A and nanofiller B is (1.5-2.5):1, and the mass ratio of chitosan quaternary ammonium salt to the total amount of nanofiller A and nanofiller B is (3-4):

1.

7. The process for preparing a high-pressure resistant polyurethane material for solid-state battery packaging according to claim 5, characterized in that: The volume ratio of the HCl aqueous solution to the total amount of vinyltriethoxysilane, aminotriethoxysilane and phenyldiethoxysilane is 1:(12-14), and the HCl aqueous solution is a (2-3) mol / L hydrochloric acid solution.

8. The process for preparing a high-pressure resistant polyurethane material for solid-state battery packaging according to claim 1, characterized in that: The raw material components of the polyurethane material include, by mass, 40-50 parts of polyol, 35-45 parts of isocyanate, 0.2-0.4 parts of dibutyltin dilaurate, 2-4 parts of chain extender, 13-15 parts of coated modified composite filler, 15-20 parts of silicon boron modifier and 0.8-1.2 parts of tetrabutyl titanate.

9. A high-pressure resistant polyurethane material for solid-state battery packaging, characterized in that: It is prepared by the preparation process of a high-pressure resistant polyurethane material for solid-state battery packaging as described in any one of claims 1 to 8.

Images