Electrolyte-based semi-solid battery and method of making the same

Abstract

The application discloses a kind of based on electrolyte's semi-solid battery and preparation method thereof, it is related to battery preparation technical field.In the present application, by preparing the modified filler that surface is coated with organic layer, and polymer matrix and other auxiliary agent are mixed to form solid electrolyte slurry, spray on positive and negative electrode sheet, obtain composite electrode sheet;The present application also prepares the modified polyvinylidene fluoride containing quaternary ammonium salt and flame-retardant polyurethane elastomer, and the two are blended, and composite diaphragm is obtained by electrospinning, the quaternary ammonium salt on the surface of diaphragm forms electrostatic adsorption with anion in electrolyte, hinders anion migration with lithium ion, improves the transmission efficiency of lithium ion;Flame-retardant polyurethane elastomer has swelling in electrolyte, can absorb electrolyte to form gel, compared with the semi-solid electrolyte obtained by in-situ polymerization method, the mechanical property of composite diaphragm is better, and the puncture resistance of composite diaphragm is higher, and the safety of the obtained semi-solid battery is better.

Description

Technical Field

[0001] This invention relates to the field of battery manufacturing technology, specifically to a semi-solid-state battery based on an electrolyte and its manufacturing method. Background Technology

[0002] In recent years, with the popularization of new energy vehicles, battery safety performance and energy density have become key factors for the advancement of the new energy industry. Although traditional liquid lithium-ion batteries have achieved large-scale application, they still have drawbacks. In the event of a severe collision or puncture, the organic electrolyte inside a lithium-ion battery may ignite or explode, posing a serious safety hazard. Semi-solid-state batteries, based on a "solid-liquid synergistic" design, have become a key technology for the transition from liquid lithium batteries to all-solid-state batteries, and have broad development prospects.

[0003] In the prior art, most semi-solid batteries are prepared by in-situ polymerization, which has been disclosed in many documents and patents. For example, CN202210615922.8 discloses a method for preparing a semi-solid battery and its application, in which a polymerizing agent and a liquid electrolyte are mixed. The polymerizing agent contains a solvent with cationic polymer function or a gelling factor with cationic polymer function, which initiates the gelation of the electrolyte to obtain a semi-solid battery with low impedance and high energy density. However, the gel electrolyte formed by in-situ polymerization has poor mechanical properties, short cycle life, and uneven polymerization inside the gel electrolyte, which is prone to failure.

[0004] Therefore, this application proposes a semi-solid battery based on an electrolyte and a method for preparing the same, which improves the overall performance of the semi-solid battery by enhancing the mechanical properties of the gel semi-solid electrolyte. Summary of the Invention

[0005] The purpose of this invention is to provide a semi-solid-state battery based on an electrolyte and its preparation method, so as to solve the problems raised in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing a semi-solid-state battery based on an electrolyte, comprising the following steps: Take composite positive electrode, composite negative electrode and composite separator, stack, wind and package them in the order of composite positive electrode - composite separator - composite negative electrode, inject electrolyte, let stand to swell, and obtain semi-solid battery.

[0007] Furthermore, the surfaces of the composite positive electrode and the composite negative electrode are coated with a solid electrolyte slurry; The composite diaphragm is prepared by electrospinning after blending modified polyvinylidene fluoride, flame-retardant polyurethane elastomer, solvent and compatibilizer.

[0008] Furthermore, the solvent is a mixture of N,N-dimethylacetamide and acetone.

[0009] Furthermore, the process conditions for static swelling are: temperature 25~30℃, time 6~12h.

[0010] Furthermore, the electrolyte comprises the following components by mass percentage: 22-30% dimethyl carbonate, 24-28% ethyl methyl carbonate, 22-28% ethylene carbonate, 0.50-1.0% ethylene sulfate, 10-14% lithium bis(fluorosulfonyl)imide, and 0.50-1.0% methanedisulfonate.

[0011] Furthermore, the composite positive electrode and composite negative electrode are prepared by the following process: S1: Inorganic filler and 2,5-dihydroxyterephthalaldehyde solution are mixed and dispersed evenly. 4'-diaminodibenzo-18-crown-6, 2,4,6-tris(4-aminophenyl)-1,3,5-triazine and acetic acid are added, stirred evenly, heated to react, and dried to obtain modified filler. S2: Mix polyvinylidene fluoride-hexafluoropropylene, lithium bis(trifluoromethanesulfonyl)imide, modified filler, N-methylpyrrolidone and polyvinylidene fluoride, stir evenly to obtain solid electrolyte slurry; S3: Take the positive electrode active material and binder, conductive agent and N-methyl-2-pyrrolidone and mix them evenly to obtain a positive electrode slurry. Coat the upper and lower surfaces of the aluminum foil, dry it to obtain a positive electrode sheet. Use electrostatic atomization spraying to spray the solid electrolyte slurry onto the upper and lower surfaces of the positive electrode sheet respectively. Vacuum dry to form a solid electrolyte layer. Hot press treatment to obtain a composite positive electrode sheet. S4: Mix the negative electrode active material with binder, conductive agent and N-methyl-2-pyrrolidone evenly to obtain a negative electrode slurry. Coat the upper and lower surfaces of the copper foil, dry it to obtain a negative electrode sheet. Use electrostatic atomization spraying to spray the solid electrolyte slurry onto the upper and lower surfaces of the negative electrode sheet respectively. Vacuum dry to form a solid electrolyte layer. Hot press treatment to obtain a composite negative electrode sheet.

[0012] Furthermore, in S1, the ratio of inorganic filler, 2,5-dihydroxyterephthalaldehyde solution, 4'-diaminodibenzo-18-crown-6, 2,4,6-tris(4-aminophenyl)-1,3,5-triazine, and acetic acid is 10g:100mL:(1.8~2.8)g:(3~5)g:(0.05~0.10)g.

[0013] Furthermore, the 2,5-dihydroxyterephthalaldehyde solution uses ethanol as a solvent; The mass fraction of 2,5-dihydroxyterephthalaldehyde solution is 40-60%.

[0014] Furthermore, in S1, the inorganic filler is one or more of titanium dioxide, zirconium oxide, and graphene, or a mixture thereof.

[0015] Furthermore, in S1, the process conditions for the heating reaction are: temperature 100~120℃, time 0.5~1.5h; In S1, the drying process conditions are: temperature 50~60℃, time 6~10h.

[0016] Furthermore, in S2, the mass ratio of polyvinylidene fluoride-hexafluoropropylene, lithium bis(trifluoromethanesulfonyl)imide, modified filler, N-methylpyrrolidone and polyvinylidene fluoride is 1:(1.0~1.5):(0.01~0.05):(30~50):(0.2~0.6).

[0017] Furthermore, in S3, the mass ratio of the positive electrode active material, binder, conductive agent, and N-methyl-2-pyrrolidone is (90~95):(0.8~1.2):(1.5~2.0):(200~300).

[0018] Furthermore, the positive electrode active material is one or a mixture of lithium cobalt oxide, lithium nickel cobalt manganese oxide, and lithium nickel cobalt aluminum oxide.

[0019] Furthermore, the aluminum foil has a thickness of 10~14μm; The coating thickness of the positive electrode slurry is 100~200μm.

[0020] Furthermore, in S4, the mass ratio of the negative electrode active material, binder, conductive agent, and N-methyl-2-pyrrolidone is (92~96):(0.8~1.2):(1.5~2.0):(200~300).

[0021] Furthermore, in S4, the negative electrode active material is one or more of graphite, hard carbon, and soft carbon.

[0022] Furthermore, in S4, the copper foil thickness is 8~12μm; The coating thickness of the negative electrode slurry is 100~200μm.

[0023] Furthermore, the coating thickness of the solid electrolyte slurry is 10~20μm.

[0024] Furthermore, in S3 and S4, the adhesive is one or more of polyvinylidene fluoride, polyacrylic acid, and polyacrylonitrile; In S3 and S4, the conductive agent is one or more of conductive carbon black, graphene, and carbon nanotubes.

[0025] Furthermore, in S3 and S4, the drying process conditions are: temperature 50~70℃, time 10~12h.

[0026] Furthermore, in S3 and S4, the process conditions for electrostatic atomization spraying are: voltage 80~90KV, spraying pressure 0.3~0.5MPa, spraying distance 50~60mm, and spraying flow rate 10~15mL / min.

[0027] Furthermore, in S3 and S4, the vacuum drying process conditions are: temperature 70~80℃, time 8~10h; In S3 and S4, the hot pressing process conditions are: temperature 100~120℃, pressure 0.3~0.5MPa, and time 20~30min.

[0028] In the above technical solution, the inorganic filler is first dispersed in a 2,5-dihydroxyterephthalaldehyde solution. The hydroxyl groups on the surface of the inorganic filler form hydrogen bonds with 2,5-dihydroxyterephthalaldehyde, introducing aldehyde groups onto the filler surface. Then, under the action of acetic acid, the amino groups of 4'-diaminodibenzo-18-crown-6 and 2,4,6-tris(4-aminophenyl)-1,3,5-triazine undergo aldehyde-amine condensation with the two aldehyde groups, thereby coating the filler surface and obtaining a modified filler. Then, the modified filler, polyvinylidene fluoride-hexafluoropropylene, and other additives are mixed to obtain a solid electrolyte slurry, which is sprayed onto the surfaces of the positive and negative electrode current collectors to form a solid electrolyte layer, which can prevent the positive and negative electrode sheets from directly contacting the electrolyte and reduce corrosion.

[0029] Furthermore, the composite diaphragm is prepared by the following process: Step A: Mix polyvinylidene fluoride, diethylaminoethyl methacrylate, N,N-dimethylformamide, and benzoyl peroxide, stir evenly, heat to react, let stand, filter, wash, dry, then add 3-chloro-2-methylpropene and acetonitrile, heat to reflux to react, filter, wash, and dry to obtain modified polyvinylidene fluoride; Step B: Mix nitrogen- and phosphorus-containing polyols, isoflurane diisocyanate, and catalyst evenly, and then cure, cool, and granulate under a nitrogen atmosphere to obtain flame-retardant polyurethane elastomer. Step C: Mix modified polyvinylidene fluoride, N,N-dimethylacetamide, acetone, flame-retardant polyurethane elastomer, and compatibilizer, dissolve in water bath by stirring, and electrospin to obtain a composite membrane.

[0030] Furthermore, in step A, the mass ratio of polyvinylidene fluoride, diethylaminoethyl methacrylate, N,N-dimethylformamide, benzoyl peroxide, 3-chloro-2-methylpropene, and acetonitrile is 1:(1~3):(30~50):(0.03~0.08):(3.5~4.5):(30~50).

[0031] Furthermore, in step A, the process conditions for the heating reaction are: temperature 60~80℃, time 7~9h; The process conditions for the reflux reaction are: temperature 80~90℃, time 20~24h.

[0032] Furthermore, in step A, the drying process conditions are: temperature 40~60℃, time 6~10h.

[0033] Furthermore, in step B, the mass ratio of nitrogen-containing phosphorus polyol to isoflurane diisocyanate is 1:(0.5~1.0). In step B, the mass of the catalyst accounts for 0.05 to 0.1% of the mass of the nitrogen- and phosphorus-containing polyol.

[0034] Furthermore, in step B, the catalyst is one or a mixture of two of dibutyltin dilaurate and stannous octoate.

[0035] Furthermore, in step B, the curing process conditions are: temperature 110~120℃, time 3~6h.

[0036] Furthermore, in step C, the mass ratio of modified polyvinylidene fluoride, N,N-dimethylacetamide, acetone, flame-retardant polyurethane elastomer, and compatibilizer is 1:(2~4):(8~12):(0.05~0.15):(0.1~0.3).

[0037] Furthermore, in step C, the compatibilizer is hydroxyl-terminated butadiene-acrylonitrile rubber.

[0038] Furthermore, in step C, the temperature for dissolving by stirring in a water bath is 30~40℃.

[0039] Furthermore, in step C, the electrospinning process conditions are: injection voltage 15~20kV, injection distance 10~15cm, and injection rate 1.58~1.78mL / h.

[0040] Furthermore, the preparation process of the nitrogen- and phosphorus-containing polyol is as follows: Step 1: Mix phosphorus oxychloride and 1,2-dichloroethane, add hydroxyethyl methacrylate and an acid-binding agent under ice bath conditions, and stir for 20-24 hours to obtain a compound containing double bonds; Step 2: Mix the compound containing double bonds and ethanol, add diisopropanolamine, stir and react to obtain a nitrogen- and phosphorus-containing polyol.

[0041] Furthermore, in step 1, the molar ratio of phosphorus oxychloride, 1,2-dichloroethane, hydroxyethyl methacrylate, and acid-binding agent is (1~3):100:(3~5):(3~4).

[0042] Furthermore, in step 1, the acid-binding agent is triethylamine.

[0043] Furthermore, in step 2, the mass ratio of the compound containing the double bond, ethanol, and diisopropanolamine is 1:(40~50):(3~7).

[0044] Furthermore, in step 2, the process conditions for the stirring reaction are: temperature 20~25℃, time 12~18h, and rotation speed 100~200r / min.

[0045] In the above technical solution, hydroxyethyl methacrylate is used to attack phosphorus oxychloride, chloride ions leave, forming a compound containing a double bond. Then, the secondary amino group of diisopropanolamine is used to attack the β carbon of the double bond to carry out a Michael addition reaction, yielding a nitrogen-phosphorus polyol. Modified polyvinylidene fluoride (PVDF) is obtained by introducing tertiary amine groups through a free radical addition reaction between polyvinylidene fluoride (PVDF) and diethylaminoethyl methacrylate (DEME) under the action of benzoyl peroxide, followed by quaternization with 3-chloro-2-methylpropene. A flame-retardant polyurethane elastomer is then generated by reacting a nitrogen-containing phosphorus polyol with isoflurane diisocyanate. Finally, the flame-retardant polyurethane elastomer, modified PVDF, modified fillers, and other additives are blended and processed through casting and stretching to obtain a composite membrane.

[0046] Compared with the prior art, the beneficial effects of the present invention are: 1. In the solid electrolyte slurry prepared in this application, the cavity structure of 4'-diaminodibenzo-18-crown-6 can form a continuous ion conduction path, thereby improving ion transport capacity. 2,4,6-tris(4-aminophenyl)-1,3,5-triazine has three-dimensional nodes, which provide rigid support for the ion transport channel. The two work together to improve ion conductivity. The organic coating layer formed on the surface of the filler in this application is amphiphilic, which can enhance compatibility with polyvinylidene fluoride-hexafluoropropylene, reduce phase separation, and improve chemical stability.

[0047] 2. In this application, a polyol containing nitrogen and phosphorus elements was synthesized. The nitrogen and phosphorus polyol was reacted with isocyanate groups to obtain a flame-retardant polyurethane elastomer, which was used to prepare a composite membrane. The swelling property of the polyurethane elastomer in carbonate electrolyte was utilized to form a gel, resulting in a semi-solid electrolyte with good electrochemical stability and excellent ionic conductivity, thus obtaining a semi-solid battery. Compared with semi-solid batteries formed by in-situ polymerization, the semi-solid electrolyte in this application has better mechanical properties, a larger solid-liquid contact area, and higher wettability of the composite porous membrane, which is beneficial to enhancing the ionic conductivity of the semi-solid battery.

[0048] 3. In this application, a tertiary amine group is introduced by reacting the free radical of polyvinylidene fluoride with diethylaminoethyl methacrylate, and then the tertiary amine group is quaternized to obtain modified polyvinylidene fluoride grafted with ester group and quaternary ammonium salt ion. Compared with ordinary polyvinylidene fluoride, it has better puncture resistance. The ester group forms hydrogen bond with the urethane bond of the polyurethane elastomer, which improves compatibility. The quaternary ammonium salt forms electrostatic adsorption with the anions in the electrolyte (mainly from lithium bis(fluorosulfonyl)imide), which hinders the migration of anions with lithium ions and improves the lithium ion transport efficiency. At the same time, the quaternary ammonium salt has strong polarity, which can significantly improve the electrolyte affinity of the composite membrane and further improve the wettability of the membrane. Detailed Implementation

[0049] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] In the following specific implementation; Aluminum foil, 14μm thick; Copper foil, 12μm thick; The positive electrode active material is lithium cobalt oxide; The negative electrode active material is graphite; model LG-0509, sourced from Henan Liugong Graphite Co., Ltd. The inorganic filler is zirconium oxide, with a particle size of 20-30 nm and a specific surface area of ​​50 m². 2 / g; 4'-Diaminodibenzo-18-crown-6, CAS number 126531-26-8; The catalyst is dibutyltin dilaurate; The adhesive is polyvinylidene fluoride, brand name Solvay 5130, sourced from Shanghai Shiruixiang Plastics Co., Ltd. The conductive agent is conductive carbon black, grade MK200, sourced from Tianjin Moke New Material Technology Co., Ltd. The compatibilizer is hydroxyl-terminated nitrile butadiene rubber, brand name SH-820, sourced from Dongguan Zhangmutou Ruiwang Plastic Raw Material Business Department; The acid-binding agent is triethylamine; Polyvinylidene fluoride, model number Arkema 761; Polyurethane elastomer, model 565AP, sourced from Changping Longcheng New Materials Business Department, Dongguan City; The electrolyte comprises the following components by mass percentage: 30% dimethyl carbonate, 28% ethyl methyl carbonate, 28% ethylene carbonate, 1.0% ethylene sulfate, 12% lithium bis(fluorosulfonyl)imide, and 1.0% methanedisulfonate.

[0051] Example 1: A method for preparing a semi-solid-state battery based on an electrolyte, comprising the following steps: (1) Preparation of nitrogen- and phosphorus-containing polyols: Step 1: Phosphorus oxychloride and 1,2-dichloroethane were mixed, and under ice bath conditions, hydroxyethyl methacrylate and an acid-binding agent were added. The mixture was stirred for 24 hours to obtain a compound containing double bonds. Step 2: The compound containing double bonds and ethanol were mixed, and diisopropanolamine was added. The mixture was stirred to obtain a nitrogen-phosphorus polyol. In Step 1, the molar ratio of phosphorus oxychloride, 1,2-dichloroethane, hydroxyethyl methacrylate, and the acid-binding agent was 3:100:5:4. In Step 2, the mass ratio of the compound containing double bonds, ethanol, and diisopropanolamine was 1:50:7. In Step 2, the stirring reaction conditions were: temperature 25℃, time 18 hours, and rotation speed 200 r / min. (2) Preparation of composite membrane: Step A: Polyvinylidene fluoride, diethylaminoethyl methacrylate, N,N-dimethylformamide, and benzoyl peroxide are mixed, stirred evenly, heated to react, allowed to stand, filtered, washed, and dried. Then, 3-chloro-2-methylpropene and acetonitrile are added, and the mixture is heated to reflux to react. After filtration, washing, and drying, modified polyvinylidene fluoride is obtained. Step B: Nitrogen-containing phosphorus polyol, isoflurane diisocyanate, and catalyst are mixed evenly, cured under a nitrogen atmosphere, cooled, and granulated to obtain flame-retardant polyurethane elastomer. Step C: Modified polyvinylidene fluoride, N,N-dimethylacetamide, acetone, flame-retardant polyurethane elastomer, and compatibilizer are mixed, dissolved in a water bath at 40°C, and electrospun to obtain a composite membrane. In Step A, polyvinylidene fluoride, diethylaminoethyl methacrylate, and N,N-dimethylformamide... The mass ratio of benzoyl peroxide, 3-chloro-2-methylpropene, and acetonitrile is 1:3:50:0.08:4.5:50; in step A, the heating reaction conditions are: temperature 80℃, time 9h; the reflux reaction conditions are: temperature 90℃, time 24h; in step A, the drying conditions are: temperature 60℃, time 10h; in step B, the mass ratio of nitrogen-phosphorus polyol and isoflurane diisocyanate is 1:1.0; in step B, the catalyst mass accounts for 0.1% of the nitrogen-phosphorus polyol mass; in step B, the aging conditions are: temperature 120℃, time 6h; in step C, the mass ratio of modified polyvinylidene fluoride, N,N-dimethylacetamide, acetone, flame-retardant polyurethane elastomer, and compatibilizer is 1:4:12:0.15:0.3. (3) Preparation of composite positive electrode and composite negative electrode: S1: Inorganic filler and 2,5-dihydroxyterephthalaldehyde solution are mixed and dispersed evenly. 4'-Diaminodibenzo-18-crown-6, 2,4,6-tris(4-aminophenyl)-1,3,5-triazine, and acetic acid are added, stirred evenly, heated to react, and dried to obtain modified filler. S2: Polyvinylidene fluoride-hexafluoropropylene, lithium bis(trifluoromethanesulfonyl)imide, modified filler, N-methylpyrrolidone, and polyvinylidene fluoride are mixed and stirred evenly to obtain solid electrolyte slurry. S3: Positive electrode active material is mixed evenly with binder, conductive agent, and N-methyl-2-pyrrolidone to obtain positive electrode slurry. It is coated on the upper and lower surfaces of aluminum foil, dried, and a positive electrode sheet is obtained. The solid electrolyte slurry is then sprayed using electrostatic atomization spraying. Vacuum drying is performed on the upper and lower surfaces of the positive electrode to form a solid electrolyte layer. Hot pressing is then applied to obtain a composite positive electrode. S4: The negative electrode active material is mixed evenly with binder, conductive agent, and N-methyl-2-pyrrolidone to obtain a negative electrode slurry. This slurry is coated onto the upper and lower surfaces of a copper foil, dried, and then the negative electrode is obtained. Electrostatic atomization spraying is used to spray the solid electrolyte slurry onto the upper and lower surfaces of the negative electrode, followed by vacuum drying to form a solid electrolyte layer. Hot pressing is then applied to obtain a composite negative electrode. In S1, the ratio of inorganic filler, 2,5-dihydroxyterephthalaldehyde solution, 4'-diaminodibenzo-18-crown-6, 2,4,6-tris(4-aminophenyl)-1,3,5-triazine, and acetic acid is 10g:100m. L: 2.8g: 5g: 0.10g; 2,5-Dihydroxyterephthalaldehyde solution with ethanol as solvent; the mass fraction of 2,5-dihydroxyterephthalaldehyde solution is 60%; in S1, the heating reaction conditions are: temperature 120℃, time 1.5h; in S1, the drying process conditions are: temperature 60℃, time 10h; in S2, the mass ratio of polyvinylidene fluoride-hexafluoropropylene, lithium bis(trifluoromethanesulfonyl)imide, modified filler, N-methylpyrrolidone and polyvinylidene fluoride is 1:1.5:0.05:50:0.6; in S3, the mass ratio of positive electrode active material, binder, conductive agent and N-methyl-2-pyrrolidone is 95:1.2:2.0:300; the coating thickness of the positive electrode slurry is 200 mm. μm; In S4, the mass ratio of negative electrode active material, binder, conductive agent, and N-methyl-2-pyrrolidone is 96:1.2:2.0:300; the coating thickness of the negative electrode slurry is 200 μm; the coating thickness of the solid electrolyte slurry is 20 μm; In S3 and S4, the drying process conditions are: temperature 70℃, time 12h; In S3 and S4, the electrostatic atomization spraying process conditions are: voltage 90KV, spraying pressure 0.5MPa, spraying distance 60mm, spraying flow rate 15mL / min; In S3 and S4, the vacuum drying process conditions are: temperature 80℃, time 10h; In S3 and S4, the hot pressing process conditions are: temperature 120℃, pressure 0.5MPa, time 30min; (4) Preparation of semi-solid-state batteries: Take composite positive electrode sheet, composite negative electrode sheet and composite separator, stack, wind and package them in the order of composite positive electrode sheet-composite separator-composite negative electrode sheet, inject electrolyte, and let them swell to obtain a semi-solid battery; the process conditions for static swelling are: temperature 30℃, time 12h.

[0052] Example 2: A method for preparing a semi-solid-state battery based on an electrolyte, comprising the following steps: (1) Preparation of nitrogen- and phosphorus-containing polyols: Step 1: Phosphorus oxychloride and 1,2-dichloroethane were mixed, and under ice bath conditions, hydroxyethyl methacrylate and an acid-binding agent were added. The mixture was stirred for 22 hours to obtain a compound containing double bonds. Step 2: The compound containing double bonds and ethanol were mixed, and diisopropanolamine was added. The mixture was stirred to obtain a nitrogen-phosphorus polyol. In Step 1, the molar ratio of phosphorus oxychloride, 1,2-dichloroethane, hydroxyethyl methacrylate, and the acid-binding agent was 2:100:4:3.5. In Step 2, the mass ratio of the compound containing double bonds, ethanol, and diisopropanolamine was 1:45:5. In Step 2, the stirring reaction conditions were: temperature 23℃, time 16 hours, and rotation speed 150 r / min. (2) Preparation of composite membrane: Step A: Polyvinylidene fluoride, diethylaminoethyl methacrylate, N,N-dimethylformamide, and benzoyl peroxide are mixed, stirred evenly, heated to react, allowed to stand, filtered, washed, and dried. Then, 3-chloro-2-methylpropene and acetonitrile are added, and the mixture is heated to reflux to react. After filtration, washing, and drying, modified polyvinylidene fluoride is obtained. Step B: Nitrogen-containing phosphorus polyol, isoflurane diisocyanate, and catalyst are mixed evenly, cured under a nitrogen atmosphere, cooled, and granulated to obtain flame-retardant polyurethane elastomer. Step C: Modified polyvinylidene fluoride, N,N-dimethylacetamide, acetone, flame-retardant polyurethane elastomer, and compatibilizer are mixed, dissolved in a water bath at 35°C, and electrospun to obtain a composite membrane. In Step A, polyvinylidene fluoride, diethylaminoethyl methacrylate, and N,N-dimethylformamide... The mass ratio of benzoyl peroxide, 3-chloro-2-methylpropene, and acetonitrile is 1:2:40:0.05:4.0:40; in step A, the heating reaction conditions are: temperature 70℃, time 8h; the reflux reaction conditions are: temperature 85℃, time 22h; in step A, the drying conditions are: temperature 45℃, time 8h; in step B, the mass ratio of nitrogen-phosphorus polyol and isoflurane diisocyanate is 1:0.8; in step B, the catalyst mass accounts for 0.08% of the nitrogen-phosphorus polyol mass; in step B, the aging conditions are: temperature 115℃, time 4h; in step C, the mass ratio of modified polyvinylidene fluoride, N,N-dimethylacetamide, acetone, flame-retardant polyurethane elastomer, and compatibilizer is 1:3:10:0.10:0.2. (3) Preparation of composite positive electrode and composite negative electrode: S1: Inorganic filler and 2,5-dihydroxyterephthalaldehyde solution are mixed and dispersed evenly. 4'-Diaminodibenzo-18-crown-6, 2,4,6-tris(4-aminophenyl)-1,3,5-triazine, and acetic acid are added, stirred evenly, heated to react, and dried to obtain modified filler. S2: Polyvinylidene fluoride-hexafluoropropylene, lithium bis(trifluoromethanesulfonyl)imide, modified filler, N-methylpyrrolidone, and polyvinylidene fluoride are mixed and stirred evenly to obtain solid electrolyte slurry. S3: Positive electrode active material is mixed evenly with binder, conductive agent, and N-methyl-2-pyrrolidone to obtain positive electrode slurry. This slurry is coated on the upper and lower surfaces of aluminum foil, dried, and the positive electrode sheet is obtained. The solid electrolyte slurry is then sprayed using electrostatic atomization spraying. The positive electrode material is coated onto the upper and lower surfaces of the positive electrode sheet, vacuum dried to form a solid electrolyte layer, and then hot-pressed to obtain a composite positive electrode sheet; S4: The negative electrode active material is mixed evenly with binder, conductive agent, and N-methyl-2-pyrrolidone to obtain a negative electrode slurry, which is coated onto the upper and lower surfaces of copper foil, dried, and then the negative electrode sheet is obtained. The solid electrolyte slurry is then sprayed onto the upper and lower surfaces of the negative electrode sheet using electrostatic atomization spraying, vacuum dried to form a solid electrolyte layer, and then hot-pressed to obtain a composite negative electrode sheet; In S1, the ratio of inorganic filler, 2,5-dihydroxyterephthalaldehyde solution, 4'-diaminodibenzo-18-crown-6, 2,4,6-tris(4-aminophenyl)-1,3,5-triazine, and acetic acid is 10g:100. mL: 2.2g: 4g: 0.08g; 2,5-Dihydroxyterephthalaldehyde solution with ethanol as solvent; the mass fraction of 2,5-dihydroxyterephthalaldehyde solution is 50%; in S1, the heating reaction conditions are: temperature 110℃, time 1.0h; in S1, the drying conditions are: temperature 55℃, time 8h; in S2, the mass ratio of polyvinylidene fluoride-hexafluoropropylene, lithium bis(trifluoromethanesulfonyl)imide, modified filler, N-methylpyrrolidone and polyvinylidene fluoride is 1:1.3:0.03:40:0.4; in S3, the mass ratio of positive electrode active material, binder, conductive agent and N-methyl-2-pyrrolidone is 93:1.0:1.8:250; the coating thickness of the positive electrode slurry is 150 mm. μm; In S4, the mass ratio of negative electrode active material, binder, conductive agent, and N-methyl-2-pyrrolidone is 94:1.0:1.8:250; the coating thickness of the negative electrode slurry is 150 μm; the coating thickness of the solid electrolyte slurry is 15 μm; In S3 and S4, the drying process conditions are: temperature 60℃, time 11h; In S3 and S4, the electrostatic atomization spraying process conditions are: voltage 85KV, spraying pressure 0.4MPa, spraying distance 55mm, spraying flow rate 13mL / min; In S3 and S4, the vacuum drying process conditions are: temperature 75℃, time 9h; In S3 and S4, the hot pressing process conditions are: temperature 110℃, pressure 0.4MPa, time 25min; (4) Preparation of semi-solid-state batteries: Take composite positive electrode sheet, composite negative electrode sheet and composite separator, stack, wind and package them in the order of composite positive electrode sheet-composite separator-composite negative electrode sheet, inject electrolyte, and let them swell to obtain a semi-solid battery; the process conditions for static swelling are: temperature 28℃, time 9h.

[0053] Example 3: A method for preparing a semi-solid-state battery based on an electrolyte, comprising the following steps: (1) Preparation of nitrogen- and phosphorus-containing polyols: Step 1: Phosphorus oxychloride and 1,2-dichloroethane were mixed, and under ice bath conditions, hydroxyethyl methacrylate and an acid-binding agent were added. The mixture was stirred for 20 hours to obtain a compound containing double bonds. Step 2: The compound containing double bonds and ethanol were mixed, and diisopropanolamine was added. The mixture was stirred to obtain a nitrogen-phosphorus polyol. In Step 1, the molar ratio of phosphorus oxychloride, 1,2-dichloroethane, hydroxyethyl methacrylate, and the acid-binding agent was 1:100:3:3. In Step 2, the mass ratio of the compound containing double bonds, ethanol, and diisopropanolamine was 1:40:3. In Step 2, the stirring reaction conditions were: temperature 20℃, time 12 hours, and rotation speed 100 r / min. (2) Preparation of composite membrane: Step A: Mix polyvinylidene fluoride, diethylaminoethyl methacrylate, N,N-dimethylformamide, and benzoyl peroxide, stir evenly, heat to react, let stand, filter, wash, dry, then add 3-chloro-2-methylpropene and acetonitrile, heat to reflux, filter, wash, and dry to obtain modified polyvinylidene fluoride; Step B: Mix nitrogen-containing phosphorus polyol, isoflurane diisocyanate, and catalyst evenly, ripen under nitrogen atmosphere, cool, and granulate to obtain flame-retardant polyurethane elastomer; Step C: Mix modified polyvinylidene fluoride, N,N-dimethylacetamide, acetone, flame-retardant polyurethane elastomer, and compatibilizer, stir and dissolve in a water bath at 30°C, electrospin to obtain composite membrane; In Step A, polyvinylidene fluoride, diethylaminoethyl methacrylate, N,N-dimethylformamide, and benzoyl peroxide are mixed and stirred evenly, heated to react, allowed to stand, filtered, washed, dried, then 3-chloro-2-methylpropene and acetonitrile are added, heated to reflux to react, filtered, washed, and dried to obtain modified polyvinylidene fluoride; Step B: Mix nitrogen-containing phosphorus polyol, isoflurane diisocyanate, and catalyst evenly, ripen under nitrogen atmosphere, cool, granulate to obtain flame-retardant polyurethane elastomer; Step C: Mix modified polyvinylidene fluoride, N,N-dimethylacetamide, acetone, flame-retardant polyurethane elastomer, and compatibilizer, stir to dissolve in a water bath at 30°C, electrospin to obtain composite membrane; The mass ratio of amine, benzoyl peroxide, 3-chloro-2-methylpropene, and acetonitrile is 1:1:30:0.03:3.5:30; in step A, the heating reaction conditions are: temperature 60℃, time 7h; the reflux reaction conditions are: temperature 80℃, time 20h; in step A, the drying conditions are: temperature 40℃, time 6h; in step B, the mass ratio of nitrogen-phosphorus polyol and isoflurane diisocyanate is 1:0.5; in step B, the catalyst mass accounts for 0.05% of the mass of nitrogen-phosphorus polyol; in step B, the aging conditions are: temperature 110℃, time 3h; in step C, the mass ratio of modified polyvinylidene fluoride, N,N-dimethylacetamide, acetone, flame-retardant polyurethane elastomer, and compatibilizer is 1:2:8:0.05:0.1. (3) Preparation of composite positive electrode and composite negative electrode: S1: Inorganic filler and 2,5-dihydroxyterephthalaldehyde solution are mixed and dispersed evenly. 4'-Diaminodibenzo-18-crown-6, 2,4,6-tris(4-aminophenyl)-1,3,5-triazine, and acetic acid are added, stirred evenly, heated to react, and dried to obtain modified filler. S2: Polyvinylidene fluoride-hexafluoropropylene, lithium bis(trifluoromethanesulfonyl)imide, modified filler, N-methylpyrrolidone, and polyvinylidene fluoride are mixed and stirred evenly to obtain solid electrolyte slurry. S3: Positive electrode active material is mixed evenly with binder, conductive agent, and N-methyl-2-pyrrolidone to obtain positive electrode slurry. This slurry is coated on the upper and lower surfaces of aluminum foil, dried, and the positive electrode sheet is obtained. The solid electrolyte slurry is then sprayed using electrostatic atomization spraying. The positive electrode material is coated onto the upper and lower surfaces of the positive electrode sheet, vacuum dried to form a solid electrolyte layer, and then hot-pressed to obtain a composite positive electrode sheet; S4: The negative electrode active material is mixed evenly with binder, conductive agent, and N-methyl-2-pyrrolidone to obtain a negative electrode slurry, which is coated onto the upper and lower surfaces of copper foil, dried, and then the negative electrode sheet is obtained. The solid electrolyte slurry is then sprayed onto the upper and lower surfaces of the negative electrode sheet using electrostatic atomization spraying, vacuum dried to form a solid electrolyte layer, and then hot-pressed to obtain a composite negative electrode sheet; In S1, the ratio of inorganic filler, 2,5-dihydroxyterephthalaldehyde solution, 4'-diaminodibenzo-18-crown-6, 2,4,6-tris(4-aminophenyl)-1,3,5-triazine, and acetic acid is 10g:100. mL: 1.8g: 3g: 0.05g; 2,5-Dihydroxyterephthalaldehyde solution with ethanol as solvent; the mass fraction of 2,5-dihydroxyterephthalaldehyde solution is 40%; in S1, the heating reaction conditions are: temperature 100℃, time 0.5h; in S1, the drying conditions are: temperature 50℃, time 6h; in S2, the mass ratio of polyvinylidene fluoride-hexafluoropropylene, lithium bis(trifluoromethanesulfonyl)imide, modified filler, N-methylpyrrolidone and polyvinylidene fluoride is 1:1.0:0.01:30:0.2; in S3, the mass ratio of positive electrode active material, binder, conductive agent and N-methyl-2-pyrrolidone is 90:0.8:1.5:200; the coating thickness of the positive electrode slurry is 100 mm. μm; In S4, the mass ratio of negative electrode active material, binder, conductive agent, and N-methyl-2-pyrrolidone is 92:0.8:1.5:200; the coating thickness of the negative electrode slurry is 100 μm; the coating thickness of the solid electrolyte slurry is 10 μm; In S3 and S4, the drying process conditions are: temperature 50℃, time 10h; In S3 and S4, the electrostatic atomization spraying process conditions are: voltage 80KV, spraying pressure 0.3MPa, spraying distance 50mm, spraying flow rate 10mL / min; In S3 and S4, the vacuum drying process conditions are: temperature 70℃, time 8h; In S3 and S4, the hot pressing process conditions are: temperature 100℃, pressure 0.3MPa, time 20min; (4) Preparation of semi-solid-state batteries: Take composite positive electrode sheet, composite negative electrode sheet and composite separator, stack, wind and package them in the order of composite positive electrode sheet-composite separator-composite negative electrode sheet, inject electrolyte, and let them swell to obtain a semi-solid battery; the process conditions for static swelling are: temperature 25℃, time 6h.

[0054] Comparative Example 1: Compared with Example 1, no solid electrolyte slurry was sprayed on the surface of the composite positive electrode and composite negative electrode. All other conditions remained the same as in Example 1.

[0055] Comparative Example 2: Compared with Example 1, the modified polyvinylidene fluoride was replaced with polyvinylidene fluoride, and the other conditions remained the same as in Example 1.

[0056] Comparative Example 3: Compared with Example 1, the flame-retardant polyurethane elastomer was replaced with a polyurethane elastomer, and the other conditions remained the same as in Example 1.

[0057] Comparative Example 4: Compared with Example 1, the solid electrolyte slurry was not sprayed on the surface of the composite positive electrode and the composite negative electrode. The modified polyvinylidene fluoride was replaced with polyvinylidene fluoride, and the other conditions remained unchanged. At the same time, the flame-retardant polyurethane elastomer was replaced with polyurethane elastomer, and the other conditions remained unchanged, the same as in Example 1.

[0058] Experiment: The semi-solid-state batteries obtained in Examples 1-3 and Comparative Examples 1-4 were tested for various properties; Needle penetration test: On a safety testing machine, an 8mm high-temperature resistant steel needle is used to penetrate the battery from a direction perpendicular to the large surface of the battery at a speed of 25mm / s. The penetration point is close to the geometric center of the large surface. The steel needle stays in the battery and the battery condition is observed. Cyclic stability test: At 60℃, charge and discharge cycle at 1C rate, and charge and discharge test at 0.2C rate every 50 cycles, monitor the capacity retention rate of the battery, stop the test when the capacity decays to 80%, and record the cycle life at this time. Wetting test: Take the composite membranes obtained in the examples and comparative examples, cut them into 10×10cm samples, and use a contact angle measuring instrument to test their contact angles to characterize the wettability of the composite membranes. Ionic conductivity test: Take a sample of the composite membrane and test its ionic conductivity using the AC impedance method. Based on the data in the table above, the following conclusions can be drawn: Compared with Example 1, Comparative Example 1 did not spray solid electrolyte slurry on the surface of composite positive electrode and composite negative electrode. The needle penetration performance and cycle performance of the semi-solid battery decreased because the solid electrolyte layer formed by the solid electrolyte slurry can prevent the positive and negative electrode from directly contacting the electrolyte, reduce erosion, and thus improve the cycle life of the semi-solid battery. Compared with Example 1, Comparative Example 2 replaced modified polyvinylidene fluoride with polyvinylidene fluoride. The needle penetration performance and cycle performance of the semi-solid battery decreased because the modified polyvinylidene fluoride has a higher degree of crosslinking and better mechanical properties, and has better puncture resistance than ordinary polyvinylidene fluoride. Compared with Example 1, Comparative Example 3 replaced the flame-retardant polyurethane elastomer with a polyurethane elastomer, and fire started to occur because ordinary polyurethane elastomer does not contain flame-retardant elements, and the flame retardancy of the semi-solid battery decreased. Compared with Example 1, the performance of Comparative Example 4 decreased significantly, indicating that the preparation of composite electrodes and composite separators in this application can promote the overall improvement of the safety and service life of the prepared semi-solid-state battery.

[0059] Based on the data in the table above, the following conclusions can be drawn: Compared with Example 1, the contact angle and ionic conductivity of Comparative Example 1 and Comparative Example 3 did not change much, indicating that the properties of polyurethane elastomer have little effect on the wettability and ionic conductivity of the composite membrane. Compared with Example 1, the contact angle of Comparative Example 2 increased significantly and the ionic conductivity decreased. This is because the quaternary ammonium salt ions of the modified polyvinylidene fluoride in this application can hinder the migration of anions with lithium ions, improve the lithium ion transport efficiency, and the strong polarity of the quaternary ammonium salt can greatly improve the electrolyte affinity of the composite membrane, further improving the wettability of the membrane.

[0060] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A method for preparing a semi-solid-state battery based on an electrolyte, characterized in that: Includes the following steps: Take composite positive electrode, composite negative electrode and composite separator, stack, wind and package them in the order of composite positive electrode - composite separator - composite negative electrode, inject electrolyte, let stand to swell, and obtain semi-solid battery; The surfaces of the composite positive electrode and the composite negative electrode are coated with a solid electrolyte slurry. The composite diaphragm is prepared by electrospinning a blend of modified polyvinylidene fluoride and flame-retardant polyurethane elastomer.

2. The method for preparing a semi-solid-state battery based on an electrolyte according to claim 1, characterized in that: The solid electrolyte slurry is prepared by the following process: S1: Inorganic filler and 2,5-dihydroxyterephthalaldehyde solution are mixed and dispersed evenly. 4'-diaminodibenzo-18-crown-6, 2,4,6-tris(4-aminophenyl)-1,3,5-triazine and acetic acid are added, stirred evenly, heated to react, and dried to obtain modified filler. S2: Mix polyvinylidene fluoride-hexafluoropropylene, lithium bis(trifluoromethanesulfonyl)imide, modified filler, N-methylpyrrolidone and polyvinylidene fluoride, stir evenly to obtain solid electrolyte slurry.

3. The method for preparing a semi-solid-state battery based on an electrolyte according to claim 1, characterized in that: The composite diaphragm is prepared by the following process: Step A: Mix polyvinylidene fluoride, diethylaminoethyl methacrylate, N,N-dimethylformamide, and benzoyl peroxide, stir evenly, heat to react, let stand, filter, wash, dry, then add 3-chloro-2-methylpropene and acetonitrile, heat to reflux to react, filter, wash, and dry to obtain modified polyvinylidene fluoride; Step B: Mix nitrogen- and phosphorus-containing polyols, isoflurane diisocyanate, and catalyst evenly, and then cure, cool, and granulate under a nitrogen atmosphere to obtain flame-retardant polyurethane elastomer. Step C: Mix modified polyvinylidene fluoride, N,N-dimethylacetamide, acetone, flame-retardant polyurethane elastomer, and compatibilizer, dissolve in water bath by stirring, and electrospin to obtain a composite membrane.

4. The method for preparing a semi-solid-state battery based on an electrolyte according to claim 3, characterized in that: The preparation process of the nitrogen- and phosphorus-containing polyol is as follows: Step 1: Mix phosphorus oxychloride and 1,2-dichloroethane, add hydroxyethyl methacrylate and an acid-binding agent under ice bath conditions, and stir for 20-24 hours to obtain a compound containing double bonds; Step 2: Mix the compound containing double bonds and ethanol, add diisopropanolamine, stir and react to obtain a nitrogen- and phosphorus-containing polyol.

5. The method for preparing a semi-solid-state battery based on an electrolyte according to claim 2, characterized in that: In S1, the ratio of inorganic filler, 2,5-dihydroxyterephthalaldehyde solution, 4'-diaminodibenzo-18-crown-6, 2,4,6-tris(4-aminophenyl)-1,3,5-triazine, and acetic acid is 10g:100mL:(1.8~2.8)g:(3~5)g:(0.05~0.10)g.

6. The method for preparing a semi-solid-state battery based on an electrolyte according to claim 2, characterized in that: In S2, the mass ratio of polyvinylidene fluoride-hexafluoropropylene, lithium bis(trifluoromethanesulfonyl)imide, modified filler, N-methylpyrrolidone and polyvinylidene fluoride is 1:(1.0~1.5):(0.01~0.05):(30~50):(0.2~0.6).

7. The method for preparing a semi-solid-state battery based on an electrolyte according to claim 3, characterized in that: In step A, the mass ratio of polyvinylidene fluoride, diethylaminoethyl methacrylate, N,N-dimethylformamide, benzoyl peroxide, 3-chloro-2-methylpropene, and acetonitrile is 1:(1~3):(30~50):(0.03~0.08):(3.5~4.5):(30~50).

8. The method for preparing a semi-solid-state battery based on an electrolyte according to claim 3, characterized in that: In step B, the mass ratio of nitrogen-containing phosphorus polyol to isoflurane diisocyanate is 1:(0.5~1.0). In step B, the mass of the catalyst accounts for 0.05 to 0.1% of the mass of the nitrogen- and phosphorus-containing polyol.

9. The method for preparing a semi-solid-state battery based on an electrolyte according to claim 4, characterized in that: In step 1, the molar ratio of phosphorus oxychloride, 1,2-dichloroethane, hydroxyethyl methacrylate, and acid-binding agent is (1~3):100:(3~5):(3~4).

10. A semi-solid-state battery based on an electrolyte, characterized in that: The preparation method according to any one of claims 1 to 9 is used.

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