Composite polymer solid electrolyte, preparation method and solid-state battery containing composite polymer solid electrolyte

Abstract

The invention relates to a composite polymer solid electrolyte, a preparation method and a solid-state battery containing the composite polymer solid electrolyte. The electrolyte comprises the following raw materials: a polymer monomer, a lithium salt, an initiator and a solvent, the mass ratio of the polymer monomer to the lithium salt to the initiator to the solvent is (5-100): (5-30): (0-5): (0-60); according to the scheme, the PEGDA-based solid electrolyte is adopted as a matrix, and the battery interface transmission capacity is improved from the aspect of electrolyte membrane body structure modification.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of solid-state batteries, and particularly relates to a composite polymer solid-state electrolyte, a preparation method and a solid-state battery containing the same. BACKGROUND

[0002] With the continuous improvement of the performance of various electronic products, especially the rapid development of electric vehicles and large-scale energy storage technology, application devices have higher demands for the energy density, cycle life and safety of energy storage products. Full solid-state batteries have high energy density and high safety, and have attracted the attention of researchers. However, the lack of electrolyte wetting leads to poor lithium ion transmission capacity in the battery, and the poor solid-solid contact between the solid-state electrolyte and the electrode leads to large interface impedance. The polymer gel electrolyte can improve the safety performance of the battery while maintaining a certain degree of wetness.

[0003] In this work, a PEGDA-based solid-state electrolyte is used as the matrix, and the transmission capacity of the battery interface is improved by modifying the structure of the electrolyte film. A composite polymer gel electrolyte is prepared by doping and mixing the PEGDA-based solid-state electrolyte to improve the slow lithium ion transmission rate in the battery. At the same time, a polymer solid-state battery is prepared by in-situ solidification process, and a carboxylate compound, a lithium salt and a solvent are used to form a prepolymer solution, and the battery is added during the liquid injection process. Under the condition of heating, in-situ polymerization is induced to solidify into a gel polymer battery. SUMMARY

[0004] In view of the above problems of the prior art, the present application provides a composite polymer solid-state electrolyte which uses a PEGDA-based solid-state electrolyte as the matrix and improves the transmission capacity of the battery interface by modifying the structure of the electrolyte film.

[0005] To solve the above technical problems, the technical scheme adopted by the present application is as follows: a composite polymer solid-state electrolyte, the raw materials of the electrolyte comprising: a polymer monomer, a lithium salt, an initiator and a solvent; the mass ratio of the polymer monomer, the lithium salt, the initiator and the solvent is (5-100):(5-30):(0-5):(0-60).

[0006] Further, the lithium salt is selected from lithium hexafluorophosphate, LiFSI (lithium bisfluorosulfonylimide), lithium difluorophosphate modified lithium hexafluorophosphate (which can be a commercially available product, such as from Aladdin Chemical Reagent).

[0007] Further, the solvent is selected from at least one of dimethyl carbonate, fluorinated ethylene carbonate and methyl ethyl carbonate.

[0008] Further, the solvent is methyl ethyl carbonate and fluoroethylene carbonate, and the volume ratio of the methyl ethyl carbonate and the fluoroethylene carbonate is 1:1-8.

[0009] Further, the initiator is at least one of benzoyl peroxide (BPO) and azobisisobutyronitrile (AIBN).

[0010] The application also provides a solid-state battery prepared by using the composite polymer solid-state electrolyte, the structure of the battery includes a positive active material, a negative active material, a coated separator, and an in-situ solid-state electrolyte, the in-situ solid-state electrolyte is the composite polymer solid-state electrolyte, and the specific preparation steps include:

[0011] (1) mixing polyethylene glycol diacrylate monomer, acrylate monomer, lithium salt, initiator and solvent to obtain a monomer pre-polymer solution;

[0012] (2) assembling a lithium-rich manganese-based positive electrode, a lithium metal negative electrode and a coated separator into an electric core, and packaging the electric core with an aluminum plastic film to obtain a battery; then injecting the monomer pre-polymer solution obtained in step (1) into the battery to infiltrate, and then performing pressurized thermal polymerization to obtain an in-situ solid-state electrolyte, thereby obtaining a solid-state battery.

[0013] Further, the lithium salt in step (1) is selected from lithium hexafluorophosphate, LiFSI (lithium bisfluorosulfonylimide), lithium difluorophosphate modified lithium hexafluorophosphate (which can be a commercially available product, and the source can be Aladdin Chemical Reagent).

[0014] Further, the solvent in step (1) is at least one of dimethyl carbonate, fluoroethylene carbonate (FEC) and methyl ethyl carbonate (EMC).

[0015] Further, the solvent in step (1) is methyl ethyl carbonate (EMC) and fluoroethylene carbonate (FEC), and the volume ratio of the two is 1:1-8.

[0016] Further, the mass ratio of the sum of the polyethylene glycol diacrylate monomer and the acrylate monomer, the lithium salt, the initiator and the solvent in step (1) is (5-100):(5-30):(0-5):(0-60).

[0017] Further, the initiator in step (1) is at least one of benzoyl peroxide (BPO) and azobisisobutyronitrile (AIBN).

[0018] Further, the areal density of the lithium-rich manganese-based positive electrode in step (2) is 25-35 mg / cm 2 , and the compacted density is 2.3-2.5 g / cm3 .

[0019] Further, the lithium metal negative electrode in step (2) is selected from at least one of 50um ultra-thin lithium strip, 20um lithium-copper composite strip, 40um lithium-copper composite strip, and 50um lithium-copper composite strip.

[0020] Further, the infiltration time in step (2) is 12h-48h.

[0021] Further, the coating separator in step (2) is one or more of commercial PP, PE, PET porous membrane, and ceramic coating membrane.

[0022] Further, the positive electrode active material is a lithium-rich manganese-based material, and the negative electrode active material is metal lithium.

[0023] Further, the process of injecting the monomer prepolymer solution comprises:

[0024] a) first, the aluminum plastic film packaged battery is dehydrated in a vacuum oven, the temperature is 80-120℃, and the vacuum degree is -80 to -100Kpa;

[0025] b) after treatment, the battery is placed in a glove box, the unsealed is opened, the monomer prepolymer solution is sucked by a dropper, and then the injection is performed against the inner measure of the aluminum plastic film, so that the electrolyte slides into the battery along the aluminum plastic film to complete the infiltration.

[0026] Further, the configuration process of the monomer prepolymer solution comprises:

[0027] a) configuration in a glove box, ensure that oxygen≤0.01ppm, water≤0.01ppm;

[0028] b) polyethylene glycol diacrylate monomer, acrylic ester monomer, lithium salt, initiator and solvent are injected into an electrolyte bottle, a magnet is added, and a magnetic stirrer is treated for 10-240min to obtain a monomer prepolymer solution.

[0029] Further, the preparation process of the lithium-rich manganese-based positive electrode slurry comprises:

[0030] (s1) a stirring machine is used to mix PVDF (polyvinylidene fluoride) and oil-based NMP (N-methyl-2-pyrrolidone) to prepare a glue solution, wherein the mass ratio of the PVDF (polyvinylidene fluoride) and the oil-based NMP (N-methyl-2-pyrrolidone) is 0.04-0.2:1, stirring for 30-40min first, and then stirring for 2-10h, the rotor speed value is 500-3000rpm, and the prepared glue solution is sealed and stored;

[0031] (s2) mixing and stirring the glue liquid prepared in step (s1) and a plurality of conductive agents, while adding oil-based NMP (in order to reduce the viscosity), wherein the mass percentage of oil-based NMP in the finally obtained slurry is 5% to 12%, and stirring for 1 to 5 hours;

[0032] (s3) finally adding the active main material (the active main material here can be a lithium-rich positive electrode material used in the art) and stirring slowly for 35 to 45 minutes, and then stirring quickly for 2 to 10 hours;

[0033] (s4) during the feeding process, condensate water is introduced to maintain the temperature at 24 to 26℃; the viscosity is adjusted to 6500 to 8000 Pa·s, and the solid content is 65 to 75% to complete the preparation of the lithium-rich manganese-based positive electrode slurry.

[0034] Further, the conductive agent in step (s2) can be at least one of SP (carbon black), CNTs (carbon nanotubes), KS-6 (conductive graphite), ECP (ketchen black), SFG-6, VGCF, etc.

[0035] Advantages and beneficial effects of the present application:

[0036] 1. The present application adopts PEGDA-based solid-state electrolyte as the matrix, improves the battery interface transmission capacity from the modification of the electrolyte membrane body structure; a composite polymer gel-state electrolyte is prepared by doping and mixing in the PEGDA-based solid-state electrolyte to improve the slow problem of lithium ion transmission rate in the battery; at the same time, a polymer solid-state battery is prepared by using in-situ solidification process, a carboxylate compound, a lithium salt and a solvent are used to form a prepolymer solution, and a battery is added during the liquid injection process, and the in-situ polymerization is initiated under heating conditions to solidify the gel-state polymer battery.

[0037] 2. The present application provides a new type of polymer material for solid-state electrolyte, which initiates self-polymerization and solidification into a solid-state electrolyte in the battery, the polymer solid-state electrolyte uses in-situ solidification method, improves the contact between electrode and electrolyte, improves the interface properties, and reduces the interface impedance in the battery; the electrolyte contains a large amount of three-dimensional network carbon-nitrogen ring structure after solidification, has flame retardant and redox resistance, and effectively improves the safety of battery cycle. At the same time, the lithium-rich manganese-based positive electrode is matched with the lithium metal negative electrode system, which greatly improves the energy density of the battery.

[0038] 3. The solid-state polymer lithium metal battery of the present application uses a non-volatile, high lithium ion conductivity gel-state electrolyte instead of electrolyte, which can effectively adsorb electrolyte and avoid the problem of liquid leakage, and reduce the risk of short circuit corrosion caused by liquid leakage; the gel-state electrolyte used in the solid-state polymer lithium metal battery has a small internal pore size, which can effectively inhibit the growth of lithium dendrites.

[0039] 4. The application uses high energy density lithium-rich manganese-based positive electrode and metal lithium negative electrode system, and the designed gel electrolyte has high space utilization, so that the polymer solid-state battery has the advantage of higher energy density (the energy density of a 5Ah soft package battery is 500Wh / kg); the application has the advantage of high capacity by making thicker lithium-rich manganese-based positive electrode sheets; the application uses in-situ polymerization process and one-pot method, which is beneficial to large-scale production, improves the polymerization process and reduces the production cost. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 Battery charge-discharge test and cycle-coulombic efficiency graph of the application examples 6-7 and comparative examples 2-3.

[0041] Figure 2 Battery charge-discharge test graph of the application example 6.

[0042] Figure 3 Battery charge-discharge test graph of the application example 7.

[0043] Figure 4 Battery charge-discharge test graph of the application comparative example 2.

[0044] Figure 5 Battery charge-discharge test graph of the application comparative example 3.

[0045] Figure 6 The internal resistance of the battery of the application examples 6 and comparative example 2 is less than the comparative graph.

[0046] Figure 7 Structure diagram of the heating clamp used in the process of preparing the battery of the application.

[0047] Figure 8 Structure diagram of the high-temperature hot-pressing in-situ curing instrument used in the process of preparing the battery of the application.

[0048] Figure 9 Polymerization state graph of the prepolymer solution prepared in the comparative example 3 of the application after heat treatment.

[0049] Figure 10 Polymerization state graph of the prepolymer solution prepared in the comparative example 1 of the application after heat treatment.

[0050] Figure 11 Polymerization state graph of the prepolymer solution prepared in the example 1 of the application after heat treatment.

[0051] Figure 12 Polymerization state graph of the prepolymer solution prepared in the example 2 of the application after heat treatment.

[0052] Figure 13 Polymerization state graph of the prepolymer solution prepared in the example 3 of the application after heat treatment.

[0053] Figure 14 Figure of the polymerization state of the prepolymer solution prepared in Example 4 of the present application after heat treatment.

[0054] Figure 15 Figure of the polymerization state of the prepolymer solution prepared in Example 5 of the present application after heat treatment. DETAILED DESCRIPTION

[0055] The present application will be further described in detail by specific embodiments, but the present application is not limited to the following embodiments only.

[0056] Preparation Example 1

[0057] Preparation of the lithium-rich manganese-based positive electrode:

[0058] a) PVDF (polyvinylidene fluoride) and oil-based NMP (N-methyl-2-pyrrolidone) were mixed and stirred to prepare a glue solution. Specifically, slow stirring was performed for 30 min, followed by scraping treatment, and then fast stirring was performed for 3 h. The dissolution was observed and the viscosity was measured. The viscosity value was ≤15000 Pa·s. The prepared glue solution was sealed and stored. The mass ratio of PVDF (polyvinylidene fluoride) to oil-based NMP (N-methyl-2-pyrrolidone) was 0.1:1. The stirring power of the fast stirring was 35 Hz, and the dispersion speed was 3000 rpm. The stirring power of the slow stirring was 15 Hz, and the dispersion speed was 500 rpm. The parameters corresponding to the fast stirring and the slow stirring were the same as above.

[0059] b) The glue solution prepared in step a) and a plurality of conductive agents (the conductive agents can be any combination of SP, CNTs, KS-6, ECP, SFG-6, and VGCF in any ratio) were stirred uniformly, and oil-based NMP (to reduce the viscosity, the mass percentage of the newly added oil-based NMP in the obtained slurry was 10%) was added. Fast stirring was performed for 1 h.

[0060] c) Oil-based conductive slurry was added and fast stirred for 1 h (the conductive slurry here comes from Jiangsu Tian Nai Company, i.e., Jiangsu Tian Nai Science and Technology Co., Ltd., and the model is LB107-44. The addition amount is sufficient to make the viscosity of the final lithium-rich manganese-based positive electrode slurry ≤8000 Pa·s, and the solid content is controlled at 72%).

[0061] d) Finally, the active main material (lithium-rich positive electrode) was added, and slow stirring was performed for 40 min, followed by fast stirring for 3 h.

[0062] e) During the feeding process, condensed water was introduced to maintain the temperature of the reaction environment at 25±1℃.

[0063] f) The viscosity was adjusted to ≤8000 Pa·s, and the solid content was controlled at 72%, to obtain the lithium-rich manganese-based positive electrode slurry.

[0064] The following processes can be understood as conventional operation processes in the art:

[0065] Positive electrode coating, rolling process:

[0066] a) Coating area width 150mm, each side reserved 20mm empty foil, width tolerance controlled within ±0.5mm;

[0067] b) Coating weight determined by single side area density, first single side coating, weight error controlled within 1.5%;

[0068] c) Second side coating weight determined by double side area density, double side coating, weight error controlled within 1.5%;

[0069] d) Machine roll according to length 330±1mm cutting;

[0070] e) Similar process design flow as c), single side, double side cold pressing thickness determined by compact density, thickness error controlled within 1.5%.

[0071] The above area density range 25-35mg / cm 2 , compact density 2.3-2.5g / cm 3 .

[0072] Positive electrode cutting size:

[0073] a) The processed large positive electrode sheet is cut into 72*62 standard electrode sheets using a laser cutting machine;

[0074] b) The cutting path is determined by drawing, and the large electrode sheet is divided into two rows, each with 5 pieces;

[0075] Place the large electrode sheet, and pass the laser cutting head according to the preset path of the drawing, and confirm that it is placed in the right position;

[0076] d) Set the machine parameters to determine the cutting strength and speed, and cut out the standard electrode sheet.

[0077] e) Set the machine parameters to determine the cutting strength and speed, and cut out the standard electrode sheet.

[0078] The process of assembling the battery cell includes:

[0079] a) Install the electrode sheet roll material on the unwinding mechanism, and transport it to the cutting station through the traction roller, and cut according to the set size (such as cutting accuracy ±0.1mm);

[0080] b) After unwinding and tension control, the separator roll material is transported to the lamination area by the roller, ensuring that the separator is flat and wrinkle-free;

[0081] c) Visual positioning: the camera shoots the edge or marker point of the electrode sheet and the separator, the system calculates the offset and sends instructions to the mechanical arm to adjust the position;

[0082] d) Lamination process: the clamping jaw grabs the pole piece and places it on the lamination platform according to the set trajectory, and the bottom diaphragm is laid synchronously; after completing the lamination of one layer of pole piece plus diaphragm, it is fixed by light pressure through the pressing mechanism to avoid misplacement. Repeat the above steps until the set number of layers (such as 100 layers or more of the battery cell needs to be layered and pressed) is reached.

[0083] e) After lamination is completed, the whole battery cell is heat-pressed and shaped, with a temperature of 95-105℃, a pressure of 6-8MPa, and a duration of 20-30 minutes.

[0084] The tab welding process of the battery cell includes:

[0085] a) In the welding machine, the positive and aluminum tabs of the battery cell are placed in alignment on the welding head, and the positive tab is welded with an energy of 1J per layer;

[0086] b) The negative tab and the copper-plated nickel tab of the battery cell are placed in alignment on the welding head, and the negative tab is welded with an energy of 3-4J per layer;

[0087] c) Insulating tape is attached to the welded battery cell from the diaphragm to the tab adhesive position to prevent short circuit, and two 50 × 20mm (length, width, mm) rectangular tapes are used to completely cover the exposed conductive material between them.

[0088] The aluminum-plastic film packaging process of the battery cell includes:

[0089] a) Cut a 200mm wide aluminum-plastic film into a 17-20cm long rectangle;

[0090] b) Fold the aluminum-plastic film in half along the wide edge, then place the battery cell in the folded aluminum-plastic film, with the battery cell wrapped diaphragm and the aluminum-plastic film leaving 10-15mm at the front end;

[0091] c) Top side packaging is performed on the packaging machine, with a packaging strip leaving positive and negative tab grooves, then side edge packaging is performed, leaving one side for electrolyte injection (the electrolyte here is the monomer prepolymer solution prepared in the following examples without polymerization).

[0092] Example 1

[0093] (1) In an argon-filled glove box, 0.27g PEGDA (polyethylene glycol diacrylate), 0.27g acrylate, 0.0054g AIBN (azobisisobutyronitrile), 5.4g electrolyte (the electrolyte includes: the solvent is FEC fluoroethylene carbonate and EMC ethyl methyl carbonate, FEC: EMC = 5:1 by volume; the lithium salt is LiPF6 and LiPO2F2, wherein the concentration of LiPF6 in the electrolyte is 1mol / L, and LiPO2F2 is an additive in the electrolyte with a mass percentage of 10%) are mixed uniformly in an argon-filled glove box to obtain a liquid flowing monomer prepolymer solution; pour the prepared monomer prepolymer solution into a small glass bottle and stir uniformly; place the small glass bottle containing the uniform prepolymer solution in a 60℃ oven for heat treatment; the polymerization state after heat treatment is shown in Table 1.

[0094] (2) In a low dew point room, use the lithium-rich manganese-based prepared in preparation example (1) as the positive electrode, a metal lithium and copper foil composite negative electrode, and a commercial PVDF / PET porous separator to assemble a soft pack battery cell; use the polymer electrolyte prepolymer solution prepared in step (1) as the electrolyte to assemble a 1.2Ah soft pack battery.

[0095] (3) After assembly, immerse at room temperature for 48h, use a hot press formation machine, and solidify at 60℃ for 5h to obtain a solid-state lithium battery polymerized in situ.

[0096] (4) Perform 0.1C charge-discharge test on the lithium battery prepared in step (3), with a voltage range of 2.0-4.6V, and the cycle-coulombic efficiency is shown in Figure 1 , and the first circle charge-discharge curve is shown in Figure 2 .

[0097] Example 2

[0098] (1) In an argon-filled glove box, 0.162g PEGDA, 0.162g acrylate, 0.00324g AIBN, 5.4g electrolyte (the electrolyte includes: the solvent is FEC fluoroethylene carbonate and EMC ethyl methyl carbonate, FEC: EMC = 5:1 by volume; the lithium salt is LiPF6 and LiPO2F2, wherein the concentration of LiPF6 in the electrolyte is 1mol / L, and LiPO2F2 is an additive in the electrolyte with a mass percentage of 10%) are mixed uniformly in an argon-filled glove box to obtain a liquid flowing prepolymer solution.

[0099] (2) Pour the prepared prepolymer solution into a small glass bottle and stir uniformly.

[0100] (3) Place the small glass bottle containing the uniform prepolymer solution in a 60℃ oven for heat treatment.

[0101] (4) The polymerization state after heat treatment is shown in Table 1.

[0102] Example 3

[0103] (1) In the glove box filled with argon, 0.081 g of PEGDA, 0.243 g of acrylate, 0.00162 g of AIBN, and 5.4 g of electrolyte (the electrolyte includes: the solvent is FEC fluoroethylene carbonate and EMC ethyl methyl carbonate, FEC: EMC = 5:1 by volume; the lithium salt is LiPF6 and LiPO2F2, wherein the concentration of LiPF6 in the electrolyte is 1 mol / L, and LiPO2F2 is an additive in the electrolyte with a mass percentage of 10%) were mixed uniformly in the glove box filled with argon to obtain a liquid flowing prepolymer solution.

[0104] (2) The prepared prepolymer solution was poured into a small glass bottle and stirred uniformly.

[0105] (3) The small glass bottle containing the uniformly prepared prepolymer solution was placed in a 60°C oven for heat treatment.

[0106] (4) The polymerization state after heat treatment is shown in Table 1.

[0107] Example 4

[0108] (1) In the glove box filled with argon, 0.081 g of PEGDA, 0.243 g of acrylate, 0.00162 g of AIBN, and 5.4 g of electrolyte (the electrolyte includes: the solvent is FEC fluoroethylene carbonate and EMC ethyl methyl carbonate, FEC: EMC = 5:1 by volume; the lithium salt is LiPF6 and LiPO2F2, wherein the concentration of LiPF6 in the electrolyte is 1 mol / L, and LiPO2F2 is an additive in the electrolyte with a mass percentage of 10%) were mixed uniformly in the glove box filled with argon to obtain a liquid flowing prepolymer solution.

[0109] (2) The prepared prepolymer solution was poured into a small glass bottle and stirred uniformly.

[0110] (3) The small glass bottle containing the uniformly prepared prepolymer solution was placed in a 60°C oven for heat treatment.

[0111] (4) The polymerization state after heat treatment is shown in Table 1.

[0112] Example 5

[0113] (1) In the glove box filled with argon, 0.081 g of PEGDA, 0.324 g of acrylate, 0.00162 g of AIBN, 5.4 g of electrolyte (the electrolyte includes: the solvent is FEC fluorinated ethylene carbonate and EMC ethyl methyl carbonate, FEC: EMC = 5:1 by volume; the lithium salt is LiPF6 and LiPO2F2, wherein the concentration of LiPF6 in the electrolyte is 1 mol / L, and the mass percentage of LiPO2F2 in the electrolyte is 10%) are mixed uniformly in the glove box filled with argon to obtain a liquid flowing prepolymer solution.

[0114] (2) Pour the prepared prepolymer solution into a small glass bottle and stir uniformly;

[0115] (3) Place the small glass bottle containing the uniformly prepared prepolymer solution in a 60°C oven for heat treatment;

[0116] (4) The polymerization state after heat treatment is shown in Table 1.

[0117] Example 6

[0118] (1) The prepolymer solution is prepared in the same way as in (1) of Example 1.

[0119] (2) In a low dew point room, a lithium-rich manganese-based cathode with a 25 face load is used as the positive electrode, a metal lithium and copper foil composite negative electrode, and a commercial PVDF / PET porous separator are used to assemble a soft package battery.

[0120] (3) The polymer electrolyte prepolymer solution prepared in step (1) is used as the electrolyte to assemble a 1.2 Ah soft package battery.

[0121] (4) After assembly, immerse at room temperature for 48 h, use a hot press formation machine, and solidify at 60°C for 5 h to obtain a solid-state lithium battery polymerized in situ.

[0122] (5) Further, the lithium battery prepared in step (4) is subjected to 0.1C charge-discharge test, the voltage range is 2.0-4.6V, the cycle-coulombic efficiency is shown in Figure 1 , and the first charge-discharge curve is shown in Figure 2 .

[0123] Example 7

[0124] (1) The prepolymer solution is prepared in the same way as in (1) of Example 2.

[0125] (2) In a low dew point room, a lithium-rich manganese-based cathode with a 25 face load is used as the positive electrode, a metal lithium and copper foil composite negative electrode, and a commercial PVDF / PET porous separator are used to assemble a soft package battery.

[0126] (3) Reuse the polymer electrolyte prepolymer liquid prepared in step (1) as an electrolyte to assemble a 1.2 Ah soft pack battery;

[0127] (4) After assembly, immerse at room temperature for 48 h, use a hot-pressing formation machine, and solidify at 60°C for 5 h to obtain an in-situ polymerized solid-state lithium battery;

[0128] (5) Further, perform 0.1C charge-discharge tests on the lithium battery prepared in step (4) at a voltage range of 2.0-4.6V, and the cycle-coulombic efficiency is shown in Figure 1 , and the first charge-discharge curve is shown in Figure 3 ;

[0129] Comparative Example 1

[0130] (1) In an argon-filled glove box, 0.27 g of BA, 0.0054 g of AIBN (azobisisobutyronitrile), and 5.4 g of electrolyte (the electrolyte includes: solvent FEC fluoroethylene carbonate and EMC ethyl methyl carbonate, FEC: EMC = 5:1 by volume; lithium salt LiPF6 and LiPO2F2, wherein the concentration of LiPF6 in the electrolyte is 1 mol / L, and LiPO2F2 is an additive in the electrolyte with a mass percentage of 10%) were mixed uniformly in the argon-filled glove box to obtain a liquid flowing prepolymer liquid;

[0131] (2) Pour the prepared prepolymer liquid into a small glass bottle and stir uniformly;

[0132] (3) Place the small glass bottle containing the uniformly prepared prepolymer liquid in a 60°C oven for heat treatment.

[0133] (4) The polymerization state after heat treatment is shown in Table 1.

[0134] Comparative Example 2

[0135] (1) In a low dew point room, use lithium-rich manganese-based as a positive electrode, a metal lithium and copper foil composite negative electrode, and a commercial PVDF / PET porous separator to assemble a soft pack battery to assemble a soft pack battery;

[0136] (2) Reuse the electrolyte (the electrolyte includes: solvent FEC fluoroethylene carbonate and EMC ethyl methyl carbonate, FEC: EMC = 5:1 by volume; lithium salt LiPF6 and LiPO2F2, wherein the concentration of LiPF6 in the electrolyte is 1 mol / L, and LiPO2F2 is an additive in the electrolyte with a mass percentage of 10%) to assemble a soft pack battery, immerse at room temperature for 48 h after assembly to obtain a soft pack lithium battery;

[0137] Perform AC impedance tests on the lithium battery prepared in step (2), and the results are shown in Figure 1; 0.1C charge-discharge test, voltage range 2.0-4.6V, cycle-coulombic efficiency see Figure 1 , the first circle charge-discharge curve see Figure 4 .

[0138] Comparative Example 3

[0139] (1) In an argon-filled glove box, 0.27g PEGDA, 0.0054g AIBN, 5.4g electrolyte (the electrolyte includes: solvent FEC fluorinated ethylene carbonate and EMC ethyl carbonate, FEC: EMC = 5:1 by volume; lithium salt is LiPF6 and LiPO2F2, wherein the concentration of LiPF6 in the electrolyte is 1mol / L, and the mass percentage of LiPO2F2 in the electrolyte is 10%) are mixed uniformly in an argon-filled glove box to obtain a liquid flowing prepolymer solution;

[0140] (2) In a low dew point room, a lithium-rich manganese-based material with a loading of 25 faces is used as a positive electrode, a metal lithium and copper foil composite negative electrode and a commercial PVDF / PET porous separator are used to assemble a soft package battery to assemble a soft package cell;

[0141] (3) The polymer electrolyte prepolymer solution prepared in step (1) is used as an electrolyte to assemble a 1Ah soft package battery. After assembly, it is immersed at room temperature for 48h, and a hot pressing formation machine is used for curing at 60℃ for 10h to obtain an in-situ polymerized solid-state lithium battery;

[0142] (4) Further, the lithium battery prepared in step (3) is subjected to 0.1C charge-discharge test, voltage range 2.0-4.6V, cycle-coulombic efficiency see Figure 1 , the first circle charge-discharge curve see Figure 5 .

[0143] Table 1 Summary of polymerization of the prepolymer solution prepared in the above examples and comparative examples of the present application

[0144]

[0145]

[0146] According to the above examples and corresponding detection drawings, the following conclusions can be drawn:

[0147] (1) Figure 1 It is shown in Table 1 that the polymer electrolyte prepolymer solution used in Examples 6 and 7 has an energy density of 500Wh / kg when used as an electrolyte in a lithium-rich battery system to assemble a 5Ah soft package battery, and the cycle life of Comparative Examples 2 and 3 is higher than that of Examples 6 and 7.

[0148] (2) From the above examples and corresponding detection drawings, the following conclusions can be drawn: Figures 2 to 5As can be seen from the capacity-voltage curves of Examples 6 and 7 and Comparative Examples 2 and 3, the batteries all underwent normal charging and discharging without any abnormalities. The charging voltage range was concentrated between 3.8 and 4.5V, and the discharging voltage was concentrated between 3 and 4.5V.

[0149] (3) From Figure 6 It can be seen that the internal impedance of the battery in Example 6 is less than that in Comparative Example 2, which shows that the improved electrolyte formulation enhances the internal mass transfer capability of the battery.

[0150] (4) Figure 7 As shown in the diagram, 6 represents the heat transfer pressure plate; 7 represents the fixing shaft connecting the pressure plate and the housing; and 8 represents the connecting steel sheet between the pressure plates. This structure is a conventional mechanism already existing in the field and can ensure uniform pressurization. This application utilizes high-temperature instruments (…). Figure 8 The high-temperature hot-pressing in-situ curing instrument shown uses a pressurization method to complete the in-situ transformation of the polymer liquid electrolyte into a gel electrolyte. Each layer of the instrument uses... Figure 7 As shown in Figure 6, two steel plates flatly sandwich the battery cell between them. A servo motor or hydraulic cylinder drives the pressure plates to provide constant pressure. Heating tubes 9 are embedded inside the pressure plates, transferring heat through contact with the battery casing. This maintains a set temperature during the main constant-current charging phase of the battery, ensuring a stable SEI film formation process. The pressurization rate and heating power are dynamically adjusted based on real-time data from pressure and temperature sensors.

Claims

1. A composite polymer solid electrolyte, characterized in that: The raw materials for this electrolyte include: polymer monomers, lithium salts, initiators, and solvents; the mass ratio of the polymer monomers, lithium salts, initiators, and solvents is (5-100):(5-30):(0-5):(0-60).

2. The composite polymer solid electrolyte according to claim 1, characterized in that: The polymer monomers include polyethylene glycol diacrylate monomers and acrylate monomers, and the mass ratio of the polyethylene glycol diacrylate monomers and acrylate monomers is 1:1-4.

3. The composite polymer solid electrolyte according to claim 1, characterized in that: The lithium salt is selected from lithium hexafluorophosphate, lithium bis(fluorosulfonyl)imide, and lithium hexafluorophosphate modified with added lithium difluorophosphate.

4. The composite polymer solid electrolyte according to claim 1, characterized in that: The solvent is selected from at least one of dimethyl carbonate, fluoroethylene carbonate, and ethyl methyl carbonate.

5. The composite polymer solid electrolyte according to claim 1, characterized in that: The initiator is selected from at least one of benzoyl peroxide and azobisisobutyronitrile.

6. The composite polymer solid electrolyte according to claim 4, characterized in that: The solvent is ethyl methyl carbonate and fluoroethylene carbonate, and the volume ratio of ethyl methyl carbonate and fluoroethylene carbonate is 1:1 to 8.

7. A solid-state battery, characterized in that: The battery structure includes a positive electrode active material, a negative electrode active material, a coated separator, and an in-situ solid electrolyte. The in-situ solid electrolyte is the composite polymer solid electrolyte described in any one of claims 1-6. The specific preparation steps of the battery include: (1) Mix polyethylene glycol diacrylate monomer, acrylate monomer, lithium salt, initiator and solvent to obtain monomer prepolymer solution; (2) A battery cell is assembled using a lithium-rich manganese-based positive electrode, a lithium metal negative electrode and a coated separator, and then encapsulated in an aluminum-plastic film to obtain a battery; then the monomer prepolymer liquid obtained in step (1) is injected into the battery prepared above for wetting, and then subjected to pressurized thermal polymerization to obtain an in-situ solid electrolyte, thereby obtaining a solid battery.

8. The solid-state battery according to claim 7, characterized in that: The areal density of the lithium-rich manganese-based cathode described in step (2) ranges from 25 to 35 mg / cm³. 2 The compacted density is 2.3–2.5 g / cm³. 3 The lithium metal anode mentioned in step (2) is selected from at least one of 50um ultrathin lithium strip, 20um lithium copper composite strip, 40um lithium copper composite strip, and 50um lithium copper composite strip; the impregnation time mentioned in step (2) is 12h to 48h, and the pressure thermal polymerization conditions are 50-70℃ curing for 1-20h; the coated membrane mentioned in step (2) is one or more of commercial PP, PE, PET porous membranes and ceramic coated membranes.

9. The solid-state battery according to claim 8, characterized in that: The preparation process of the lithium-rich manganese-based cathode slurry includes: (s1) A mixing machine is used to mix PVDF and oil-based NMP to prepare a glue solution, wherein the mass ratio of PVDF and oil-based NMP is 0.04 to 0.2:

1. The mixture is stirred for 30 to 40 minutes and then stirred for 2 to 10 hours. The rotor speed is 500 to 3000 rpm. The prepared glue solution is sealed and stored. (s2) Mix the adhesive solution prepared in step (s1) with various conductive agents and stir, while adding oil-based NMP, wherein the mass percentage of oil-based NMP in the final slurry is 5% to 12%, and stir for 1 to 5 hours; (s3) Finally, add the active main material and stir slowly for 35-45 minutes, then stir quickly for 2-10 hours; (s4) During the feeding process, condensate water is introduced to maintain the temperature at 24-26℃; adjust the viscosity to 6500~8000Pa·s and the solid content to 65~75% to complete the preparation of lithium-rich manganese-based cathode slurry.

10. The solid-state battery according to claim 7, characterized in that: The process of injecting monomer prepolymer liquid includes: a) First, remove moisture from the battery cells packaged in aluminum-plastic film in a vacuum oven at a temperature of 80-120℃ and a vacuum degree of -80 to -100Kpa. b) After processing, place the battery in the glove box, open the unsealed side, use a dropper to draw up the monomer prepolymer liquid and press it against the inside of the aluminum-plastic film to inject the electrolyte, allowing the electrolyte to slide into the cell along the aluminum-plastic film to complete the wetting.

11. The solid-state battery according to claim 11, characterized in that: The preparation process of the monomer prepolymer liquid includes: a) Configure in a glove box to ensure oxygen ≤0.01ppm and water ≤0.01ppm; b) Inject polyethylene glycol diacrylate monomer, acrylate monomer, lithium salt, initiator and solvent into an electrolyte bottle, add a magnetic stirrer, and process with a magnetic stirrer for 10-240 min to obtain monomer prepolymer solution.

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