Integrated positive electrode, quasi-solid-state battery and preparation method

Abstract

The invention relates to the technical field of solid-state batteries, in particular to an integrated positive electrode, a quasi-solid-state battery and a preparation method. According to the integrated positive electrode provided by the invention, the conductive polymer is introduced into the positive electrode active layer and the solid electrolyte layer at the same time, so that the problem of contact between the solid electrolyte and a pole piece interface is effectively improved, and the integrated positive electrode can be prepared through in-situ curing without complex equipment; the preparation method can be directly completed on a production line of a traditional lithium ion battery, and the quasi-solid-state battery which is further prepared has relatively high safety and relatively high charge-discharge efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of solid-state batteries, and particularly relates to an integrated positive electrode, a quasi-solid-state battery and a preparation method thereof. Background Art

[0002] With the continuous innovation and iterative upgrade of lithium secondary battery material technology, lithium-ion batteries have gradually become dominant in the fields of mobile devices, electric vehicles, energy storage systems, etc., and have become one of the most widely used rechargeable chemical power sources today. As a key bridge for transporting lithium ions in the battery, the performance of the electrolyte has a decisive impact on the overall performance of the battery. Although there is still a large room for improvement in the energy density of traditional lithium-ion batteries, organic liquid electrolytes are flammable and pose great safety hazards. All-solid-state batteries have advantages such as high energy density and high safety performance, and have become the main solution for future energy storage technology. However, compared with existing products, the production of all-solid-state batteries requires a complete transformation of the existing production line, which is costly. Therefore, alternative solutions are urgently needed to solve the safety and mass production problems.

[0003] Quasi-solid-state batteries are between semi-solid state and all-solid state, without free electrolytes and have higher safety. However, the solid-solid interface contact between the solid electrolyte and the electrode is poor, and the contact resistance is high, which seriously affects the electrical performance and cycling performance of the battery. Therefore, one of the key technical problems that quasi-solid-state batteries need to overcome is to improve the interface contact between the solid electrolyte and the electrode, and at the same time overcome the problems of comprehensive update of the production process and high transformation cost. Summary of the Invention

[0004] Based on this, the present invention provides an integrated positive electrode. By simultaneously introducing a conductive polymer into the positive electrode active layer and the solid electrolyte layer, not only the interface contact problem between the solid electrolyte and the electrode sheet is effectively improved, but also the integrated positive electrode can be prepared by in-situ curing.

[0005] The present invention also provides a preparation method of the integrated positive electrode. This method does not require complex equipment and can directly prepare an integrated positive electrode with improved interface contact between the electrode sheet and the solid electrolyte on the production line of traditional lithium-ion batteries.

[0006] The present invention also provides a quasi-solid-state battery, which has high safety and high charge and discharge efficiency.

[0007] The present invention also provides a preparation method of the quasi-solid-state battery. A quasi-solid-state battery with improved interface problems can be obtained on the production line of traditional lithium-ion batteries.

[0008] The present invention provides an integrated positive electrode, which at least includes a positive electrode active layer and a solid electrolyte layer formed in sequence on a positive electrode sheet;

[0009] The positive electrode active layer includes a positive electrode active material and a conductive polymer coated on the surface of the positive electrode active material;

[0010] The solid electrolyte layer includes a solid electrolyte and a conductive polymer coated on the surface of the solid electrolyte.

[0011] By introducing the conductive polymer into both the positive electrode active layer and the solid electrolyte layer, this integrated positive electrode not only effectively improves the interfacial contact problem between the solid electrolyte and the electrode sheet, but also can be prepared by in-situ curing without complex equipment and can be completed directly on the production line of traditional lithium-ion batteries.

[0012] For the integrated positive electrode as described above, the polymerization raw materials of the conductive polymer include polymer monomers, and the polymer monomers are selected from one or more of poly(ethylene glycol) methyl ether methacrylate, polyethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol dimethyl ether, 1,3-dioxolane, and poly(ethylene glycol) methyl ether acrylate.

[0013] For the integrated positive electrode as described above, the integrated positive electrode further includes a separator, and the separator is an organic-inorganic hybrid separator.

[0014] For the integrated positive electrode as described above, in the organic-inorganic hybrid separator, the mass ratio of the organic separator material is 10-85%, and the mass ratio of the inorganic separator material is 10-85%.

[0015] For the integrated positive electrode as described above, the organic-inorganic hybrid separator further includes a conductive polymer.

[0016] The present invention also provides a preparation method for the above integrated positive electrode, including the following steps:

[0017] Coat a positive electrode slurry on the positive electrode sheet to make a positive electrode active layer. Among them, the positive electrode slurry includes a positive electrode active material, a polymer monomer, and an initiator;

[0018] Coat a solid electrolyte slurry on the positive electrode active layer to make a solid electrolyte layer. Among them, the solid electrolyte slurry includes a solid electrolyte, a polymer monomer, and an initiator.

[0019] For the preparation method as described above, the positive electrode slurry includes a main raw material and a solvent. In the main raw material, the mass ratio of the polymer monomer is 0.5-5%, and the mass ratio of the initiator is 0.05-1%.

[0020] For the preparation method as described above, the solid electrolyte slurry includes a main raw material and a solvent. In the main raw material, the mass ratio of the polymer monomer is 0.5-5%, and the addition amount of the initiator is 0.05-5%.

[0021] According to the above-described preparation method, the main raw materials of the positive electrode slurry include a positive electrode active material, a conductive agent, a binder, a lithium salt, a polymer monomer, a solid electrolyte, and an initiator. Further, based on the main raw materials, the mass ratio of the positive electrode active material is 90-95%, the mass ratio of the conductive agent is 1-5%, the mass ratio of the binder is 1-5%, the mass ratio of the lithium salt is 1-5%, the mass ratio of the polymer monomer is 0.5-5%, the mass ratio of the initiator is 0.05-1%, and the mass ratio of the solid electrolyte is 0.5-1.5%.

[0022] According to the above-described preparation method, the main raw materials of the solid electrolyte slurry include a solid electrolyte, a lithium salt, a binder, a polymer monomer, and an initiator. Further, based on the main raw materials, the mass ratio of the solid electrolyte is 45-70%, the mass ratio of the lithium salt is 1-5%, the mass ratio of the binder is 25-50%, the mass ratio of the polymer monomer is 0.5-5%, and the addition amount of the initiator is 0.05-5%.

[0023] According to the above-described preparation method, it further includes the step of coating a separator slurry on the solid electrolyte layer to make a separator.

[0024] According to the above-described preparation method, the separator slurry includes main raw materials and a solvent, and the main raw materials include an organic separator material, an inorganic separator material, a lithium salt, a dissolved electrolyte monomer, and an initiator. Further, based on the main raw materials, the mass ratio of the organic separator material is 10-85%, the mass ratio of the inorganic separator material is 10-85%, the mass ratio of the lithium salt is 2-10%, the mass ratio of the polymer monomer is 5-10%, and the mass ratio of the initiator is 0.05-1%.

[0025] The present invention also provides a quasi-solid-state battery, and the quasi-solid-state battery is composed of an integrated positive electrode including the above-mentioned one or an integrated positive electrode prepared by the above preparation method.

[0026] According to the above-described quasi-solid-state battery, the quasi-solid-state battery is further filled with a gel electrolyte, and the gel electrolyte at least includes a polymer monomer, an initiator, and an electrolyte; the mass ratio of the polymer monomer is 0.5-5%, and the mass ratio of the initiator is 0.05-1%.

[0027] The present invention also provides a preparation method of the above quasi-solid-state battery, including the following steps:

[0028] Coat the negative electrode slurry on the negative electrode plate, then stack it with the integrated positive electrode, inject the gel electrolyte after stacking is completed, and then perform in-situ polymerization and curing.

[0029] According to the above-described preparation method, a gradient curing process is adopted during the in-situ polymerization and curing treatment.

[0030] According to the above-described preparation method, the gradient curing process is as follows: curing at 40 - 60°C for 1 - 12 h and then curing at 65 - 80°C for 2 - 8 h.

[0031] By introducing a conductive polymer into both the positive active layer and the solid electrolyte layer, the present invention not only effectively improves the interfacial contact problem between the solid electrolyte and the electrode sheet, but also the integrated positive electrode can be obtained through in-situ curing without complex equipment and can be completed on the original production line of traditional lithium-ion batteries, overcoming the problems of a complete update of the production process of solid-state batteries and high transformation costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is the cyclic performance test result of the quasi-solid-state battery prepared in Example 1 of the present invention;

[0033] Figure 2 It is the cyclic performance test result of the quasi-solid-state battery prepared in Example 2 of the present invention;

[0034] Figure 3 It is the cyclic performance test result of the quasi-solid-state battery prepared in Example 3 of the present invention;

[0035] Figure 4 It is the cyclic performance test result of the quasi-solid-state battery prepared in Example 4 of the present invention;

[0036] Figure 5 It is the cyclic performance test result of the quasi-solid-state battery prepared in Example 5 of the present invention;

[0037] Figure 6 It is the cyclic performance test result of the quasi-solid-state battery prepared in Example 6 of the present invention;

[0038] Figure 7 It is the cyclic performance test result of the quasi-solid-state battery prepared in Example 7 of the present invention;

[0039] Figure 8 It is the cyclic performance test result of the quasi-solid-state battery prepared in Comparative Example 1 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] To make the objectives, technical solutions, and advantages of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Apparently, the described embodiments are part of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0041] Based on the problems of poor interfacial contact between the electrode and the electrolyte and high production line transformation costs in existing solid-state batteries, the present invention provides an integrated positive electrode, which can be prepared without modifying the existing lithium battery production line, and the interfacial contact problem between its solid electrolyte and the positive electrode is effectively improved at the same time.

[0042] An integrated positive electrode includes at least a positive electrode active layer and a solid electrolyte layer that are formed in-situ and cured on the positive electrode plate in sequence; wherein, the positive electrode active layer includes a positive electrode active material and a conductive polymer coated on the surface of the positive electrode active material; the solid electrolyte layer includes a solid electrolyte and a conductive polymer coated on the surface of the solid electrolyte.

[0043] By introducing the conductive polymer into both the positive electrode active layer and the solid electrolyte layer at the same time, the present invention can make the combination between the prepared positive electrode active layer and the solid electrolyte layer tighter, and the formed ion channels are more conducive to the transfer of ions between the positive and negative electrodes, thereby achieving the improvement of the interfacial contact problem. In addition, each layer of the integrated positive electrode can be formed by in-situ curing, without complex equipment, and can be completed directly on the production line of traditional lithium-ion batteries.

[0044] In the above, the conductive polymer is polymerized from a raw material including a polymer monomer. The polymer monomer is not specifically limited. Preferably, the polymer monomer is selected from one or more of poly(ethylene glycol) methyl ether methacrylate (PEGMA), polyethylene glycol diacrylate (PEGDA), triethylene glycol dimethacrylate (TEGDMA), triethylene glycol dimethyl ether (TEGDME), 1,3-dioxolane (DOL), and poly(ethylene glycol) methyl ether acrylate. The polymer monomer can be directly in-situ cured during the coating process through the action of an initiator, and the operation is convenient. Exemplarily, the initiator can be selected from one or a combination of two of azobisisobutyronitrile (AIBN) and aluminum trifluoromethanesulfonate Al(OTf)3.

[0045] Further, the above integrated positive electrode further includes a separator. The present invention does not strictly limit the material selection of the separator, and it can be a separator material commonly used in current batteries, such as a polypropylene separator (PP), a polyethylene separator (PE), a polypropylene / polyethylene bilayer composite film (PP / PE), a polyimide electrospun separator (PI), a polypropylene / polyethylene / polypropylene trilayer composite film (PP / PE / PP), a cellulose non-woven fabric separator, or a separator with a ceramic coating.

[0046] In some specific embodiments of the present invention, the separator is an organic-inorganic hybrid separator. Using an organic-inorganic hybrid separator to replace the traditional separator not only ensures the ion transport channels but also provides better mechanical properties, prevents lithium dendrites from piercing the separator, and improves the cycle performance of the battery.

[0047] Research shows that when the mass ratio of the organic separator material in the organic-inorganic hybrid separator is 10 - 85% and the mass ratio of the inorganic separator is 10 - 85%, the performance of the integrated positive electrode is better.

[0048] Further, when the organic-inorganic hybrid separator also contains a conductive polymer, the performance of the integrated positive electrode is better.

[0049] In the present invention, the conductive polymers in the positive electrode active layer, the solid electrolyte layer, and the organic-inorganic hybrid separator can be the same or different. Preferably, the conductive polymers in the positive electrode slurry, the solid electrolyte slurry, and the organic-inorganic composite solid electrolyte slurry are the same. Using the same conductive polymer can, on the one hand, ensure that the formed ion channels are more conducive to the transfer of ions between the positive and negative electrodes, and on the other hand, facilitate the simplification of subsequent post-treatment processes and reduce the impact of post-treatment processes on the positive electrode active layer and the solid electrolyte layer.

[0050] In the present invention, the method of forming the positive electrode active layer, the solid electrolyte layer, and the separator on the positive electrode plate is not limited. For example, the common pressing method or coating method in the art can be used.

[0051] For the preparation method of the above integrated positive electrode provided by the present invention, the positive electrode active layer and the solid electrolyte layer are both formed by coating, and specifically include the following steps:

[0052] Coat the positive electrode slurry on the positive electrode plate to form the positive electrode active layer. Among them, the positive electrode slurry includes a positive electrode active material, a polymer monomer, and an initiator;

[0053] Coat the solid electrolyte slurry on the positive electrode active layer to form the solid electrolyte layer. Among them, the solid electrolyte slurry includes a solid electrolyte, a polymer monomer, and an initiator.

[0054] The integrated positive electrode prepared by the above method can ensure that the formed ion channels are more conducive to the transfer of ions between the positive and negative electrodes, and the improvement effect of the interface contact problem is better. Moreover, this method is simple to operate and can be realized in the existing production lines of batteries.

[0055] In the above, the positive electrode slurry includes main raw materials and a solvent. When the mass ratio of the polymer monomer in the main raw materials is 0.5 - 5% and the mass ratio of the initiator is 0.05 - 1%, the performance of the integrated positive electrode is better.

[0056] Similarly, the solid electrolyte slurry includes main raw materials and a solvent. When the mass ratio of the polymer monomer in the main raw materials is 0.5 - 5% and the addition amount of the initiator is 0.05 - 5%, the performance of the integrated positive electrode can be further improved.

[0057] It can be understood that the positive electrode active layer and the solid electrolyte layer also include other conventional raw materials. For example, the positive electrode active layer also includes conventional raw materials such as conductive agents and binders, and the solid electrolyte layer also includes conventional raw materials such as binders. In the above, since both the positive electrode slurry and the solid electrolyte slurry contain polymer monomers and initiators, both the positive electrode active layer and the solid electrolyte layer can be cured during the coating process. Specifically, the in-situ curing can be achieved by adjusting the running speed of the positive electrode sheet during coating according to the components in the positive electrode slurry and the solid electrolyte slurry.

[0058] In some specific embodiments of the present invention, the positive electrode slurry includes 52 - 60% by mass of main raw materials and 40 - 48% of a solvent. The main raw materials include a positive electrode active material, a conductive agent, a binder, a lithium salt, a polymer monomer, an initiator, and a solid electrolyte. Among them, the mass ratio of the positive electrode active material in the main raw materials is 90 - 95%, the mass ratio of the conductive agent is 1 - 5%, the mass ratio of the binder is 1 - 5%, the mass ratio of the lithium salt is 1 - 5%, the mass ratio of the polymer monomer is 0.5 - 5%, the mass ratio of the initiator is 0.05 - 1%, and the mass ratio of the solid electrolyte is 0.5 - 1.5%. By adjusting the coating conditions, such as controlling the flow speed of the positive electrode sheet on the conveyor belt during coating to be 1 - 4 m / s, the in-situ curing of the positive electrode active layer can be achieved during the coating process.

[0059] In some other specific embodiments of the present invention, the solid electrolyte slurry comprises 15-20% by mass of the main raw materials and 75-80% of the solvent. Among them, the main raw materials include a solid electrolyte, a lithium salt, a binder, a polymer monomer, and an initiator. The mass proportion of the solid electrolyte is 45-70%, the mass proportion of the lithium salt is 1-5%, the mass proportion of the binder is 25-50%, the mass proportion of the polymer monomer is 0.5-5%, and the addition amount of the initiator is 0.05-5%. By regulating the coating conditions, such as controlling the flow rate of the positive electrode sheet on the conveyor belt during coating to be 1-4 m / s, in-situ curing of the solid electrolyte layer can be achieved during the coating process.

[0060] Further, the above method further comprises a step of coating an organic-inorganic composite solid electrolyte slurry on the solid electrolyte layer to form an organic-inorganic hybrid separator.

[0061] In some specific embodiments of the present invention, the organic-inorganic composite solid electrolyte slurry comprises 25-40% by mass of the main raw materials and 60-75% of the solvent. Among them, the main raw materials include an organic separator material, an inorganic separator material, a lithium salt, a monomer of a gel electrolyte, and an initiator. Among them, the mass proportion of the organic separator material is 10-85%, the mass proportion of the inorganic separator material is 10-85%, the mass proportion of the lithium salt is 2-10%, the mass proportion of the polymer monomer is 5-10%, and the mass proportion of the initiator is 0.05-1%. By regulating the coating conditions, such as controlling the flow rate of the positive electrode sheet on the conveyor belt during coating to be 1-4 m / s, in-situ curing of the organic-inorganic hybrid separator can be achieved during the coating process.

[0062] Further research also shows that when the organic separator material in the organic-inorganic hybrid separator, the binder in the solid electrolyte layer, and the binder in the positive electrode active layer are the same or similar, better interfacial contact can be ensured and the performance of the integrated positive electrode is better. It should be noted that the similarity mentioned here generally refers to the same main chain structure. The similar main chain structure of the polymer is beneficial to spontaneously form a homogeneous structure during mixing (pressure / heating), thereby forming good interfacial contact. Using an inorganic separator material with high ionic conductivity or high dielectric constant filler is beneficial to improving the ionic conductivity.

[0063] In the present invention, there are no specific limitations on the specific raw materials used, and the raw materials known in the art can be used. For example, in some specific embodiments of the present invention, the initiator is selected from one or a combination of two of azobisisobutyronitrile (AIBN) and aluminum trifluoromethanesulfonate Al(OTf)3.

[0064] The positive electrode active material is at least one composite oxide of lithium and at least one metal of cobalt, manganese, nickel, and their combinations; specifically, it can be at least one of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium manganese oxide, nickel cobalt manganese ternary material, nickel cobalt aluminum ternary material, lithium iron phosphate (LFP), lithium nickel manganese oxide, lithium-rich manganese-based material, etc. Exemplarily, the conductive agent is at least one of carbon black (Sp), acetylene black, graphene, Ketjen black, and carbon fiber. The binder is one or a combination of two of polyvinylidene fluoride (PVDF) and polyvinylidene fluoride - hexafluoropropylene copolymer (PVDF-HFP). The solvent is one of N-methylpyrrolidone (NMP), dimethylformamide (DMF), dimethylacetamide solvent (DMAC), and octadecyl dimethyl hydroxyethyl ammonium nitrate (SN). The lithium salt is selected from one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis(oxalato)borate, bis(trifluoromethylsulfonyl)imide, lithium bis(fluoroxalato)borate, and lithium bis(fluorosulfonyl)imide. The solid-state electrolyte is one or more of LATP, LLZTO, and LLTO.

[0065] Exemplarily, the organic separator material is one or more of polyvinylidene fluoride (PVDF), polyvinylidene fluoride - trifluoroethylene - chlorotrifluoroethylene (PVDF-TRFE-CTFE), polyvinylidene fluoride - hexafluoropropylene (PVDF-HFP), polyimide (PI), and polyacrylonitrile (PAN). The inorganic separator material can select fillers with high ionic conductivity or high dielectric constant, such as lithium aluminum titanium phosphate (LATP), lanthanum zirconium lithium oxide (LLZO), lithium lanthanum titanium oxide (LLTO), tantalum-doped lanthanum zirconium lithium oxide (LLZTO), silicon oxide, aluminum oxide, hafnium oxide, barium titanate, and boron nitride.

[0066] It can be understood that in each specific embodiment, the selection of the above lithium salt, polymer monomer, solvent, or solid-state electrolyte in the solid-state electrolyte slurry and / or the organic-inorganic composite solid-state electrolyte slurry can be the same as or different from that in the positive electrode slurry.

[0067] The quasi-solid-state battery provided by the present invention is formed by laminating the above-mentioned integrated positive electrode or the integrated positive electrode prepared by the above preparation method with a negative electrode sheet, and a gel electrolyte is injected therein.

[0068] In some specific embodiments of the present invention, the gel electrolyte includes at least a polymer monomer, an initiator, and an electrolyte (that is, a polymer monomer and an initiator are added on the basis of a conventional electrolyte). The mass ratio of the polymer monomer is 0.5 - 5%, and the mass ratio of the initiator is 0.05 - 1%.

[0069] The present invention does not strictly limit the selection of the conventional electrolyte, which may include one or more of the solvents commonly used in current lithium-ion battery electrolytes, as well as the electrolyte lithium salts commonly used in current lithium-ion electrolytes. For example, the solvent can be ethylene carbonate, propylene carbonate, butylene carbonate, fluoroethylene carbonate (FEC), dimethyl carbonate (DMC), diethyl carbonate (DEC), difluoroethylene carbonate (DFEC), dipropyl carbonate, ethyl methyl carbonate (EMC), ethyl acetate, ethyl propionate, propyl acetate, propyl propionate, sulfolane, γ-butyrolactone, etc.; the lithium salt can be, for example, one or more of lithium hexafluorophosphate (LiPF6), lithium bis(fluorosulfonyl)imide (LiFSI), and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI).

[0070] The present invention also provides a method for preparing the above quasi-solid-state battery, including the following steps: coating the negative electrode slurry on the negative electrode sheet, then laminating it with the integrated positive electrode, injecting the gel electrolyte after lamination is completed, and then performing in-situ polymerization and curing.

[0071] Furthermore, a gradient curing process is adopted during the in-situ polymerization and curing treatment, where the gradient curing process is: curing at 40 - 60 °C for 3 - 8 h and curing at 60 - 80 °C for 2 - 4 h. This gradient curing process can further improve the wettability of the gel electrolyte to the electrode sheet and improve the capacity utilization and energy density.

[0072] The following will specifically describe the integrated positive electrode, its preparation method, and the quasi-solid-state battery of the present invention with reference to specific embodiments.

[0073] The conventional electrolyte used in the following examples is the ZT-09 electrolyte purchased from Kunlun New Materials Technology Co., Ltd.

[0074] Example 1

[0075] This example provides a method for preparing a quasi-solid-state battery, and the specific steps are as follows:

[0076] (1) Preparation of the integrated positive electrode

[0077] Positive electrode mixing and coating: Prepare a positive electrode slurry, which includes 58% by mass of the main raw materials and 42% by mass of the solvent DMF. The main raw materials include the following components by mass percentage: lithium iron phosphate 91.7 wt%, conductive agent SP 1.7 wt%, binder PVDF 1.7 wt%, lithium hexafluorophosphate 1.4 wt%, polymer monomer PEGMA 2.4 wt%, solid electrolyte LATP 1 wt%, and initiator AIBN 0.1 wt%. Coat the prepared positive electrode slurry on the positive electrode sheet aluminum foil, and adjust the flow rate of the conveyor belt to 2.5 m / s during coating to complete curing during the coating process.

[0078] Coating of solid electrolyte slurry: Prepare a solid electrolyte slurry, which includes 20% by mass of main raw materials and 80% of solvent DMF. The main raw materials include the following components by mass percentage: lithium hexafluorophosphate 2.9wt%, polymer monomer PEGMA 1wt%, solid electrolyte LATP 48wt%, initiator AIBN 0.1wt%, binder PVDF-HFP 48wt%. Coat the prepared positive electrode slurry on the aluminum foil of the positive electrode. During coating, adjust the flow rate of the conveyor belt to 2m / s to complete curing during the coating process.

[0079] Coating of separator slurry: Prepare an organic-inorganic composite solid electrolyte slurry, which includes 30% by mass of main raw materials and 70% of solvent DMF. The main raw materials include the following components by mass percentage: organic separator material PVDF-TRFE-CTFE 46wt%, inorganic separator material LATP 45wt%, lithium hexafluorophosphate 3wt%, polymer monomer PEGMA 5wt%, initiator AIBN 1wt%. Coat the prepared positive electrode slurry on the aluminum foil of the positive electrode. During coating, adjust the flow rate of the conveyor belt to 2m / s to complete curing during the coating process.

[0080] (2) Preparation of negative electrode

[0081] Mixing and coating of negative electrode: Prepare a negative electrode slurry, and the components and contents are as follows: graphite 45wt%, binder PVDF 2.8wt%, conductive agent SP 1wt%, water 51.2wt%. Coat the prepared negative electrode slurry on copper foil and cure it in an oven to obtain the negative electrode.

[0082] (3) Preparation of quasi-solid-state battery

[0083] Stack the integrated positive electrode and negative electrode prepared above, and inject the gel electrolyte after stacking. The gel electrolyte consists of 2wt% of polymer monomer PEGMA by mass percentage, 1wt% of initiator AIBN by mass percentage, and 97wt% of conventional electrolyte.

[0084] (4) Gradient curing

[0085] The quasi-solid-state battery after the above injection is first cured at 50°C for 5h, and then cured at 75°C for 3h to obtain the final quasi-solid-state battery.

[0086] Example 2

[0087] This example provides a method for preparing a quasi-solid-state battery, and the specific steps are as follows:

[0088] (1) Preparation of Integrated Cathode

[0089] Cathode Mixing and Coating: Prepare cathode slurry. The cathode slurry includes 58% by mass of main raw materials and 42% of solvent DMF. The main raw materials include the following components by mass percentage: lithium iron phosphate 90wt%, conductive agent SP 1wt%, binder PVDF 1wt%, lithium hexafluorophosphate 1wt%, polymer monomer PEGMA 5wt%, solid electrolyte LATP 1wt%, initiator AIBN 1wt%. Coat the prepared cathode slurry on the aluminum foil of the cathode current collector. During coating, adjust the flow rate of the conveyor belt to 2.5 m / s to complete curing during the coating process.

[0090] Solid Electrolyte Slurry Coating: Prepare solid electrolyte slurry. The solid electrolyte slurry includes 20% by mass of main raw materials and 80% of solvent DMF. The main raw materials include the following components by mass percentage: lithium hexafluorophosphate 2wt%, polymer monomer PEGMA 5wt%, solid electrolyte LATP 60wt%, initiator AIBN 4wt%, binder PVDF - HFP 29wt%. Coat the prepared cathode slurry on the aluminum foil of the cathode current collector. During coating, adjust the flow rate of the conveyor belt to 2 m / s to complete curing during the coating process.

[0091] Separator Slurry Coating: Prepare organic - inorganic composite solid electrolyte slurry. The organic - inorganic composite solid electrolyte slurry includes 30% by mass of main raw materials and 70% of solvent DMF. The main raw materials include the following components by mass percentage: organic separator material PVDF - TRFE - CTFE 46wt%, inorganic separator material LATP 45wt%, lithium hexafluorophosphate 3wt%, polymer monomer PEGMA 5wt%, initiator AIBN 1wt%. Coat the prepared cathode slurry on the aluminum foil of the cathode current collector. During coating, adjust the flow rate of the conveyor belt to 2 m / s.

[0092] (2) Preparation of Anode

[0093] Anode Mixing and Coating: Prepare anode slurry, with the components and contents as follows: graphite 45wt%, binder 2.8wt%, conductive agent SP 1wt%, water 51.2wt%. Coat the prepared anode slurry on copper foil and cure it in an oven to obtain the anode.

[0094] (3) Preparation of Quasi - Solid - State Battery

[0095] The integrated positive electrode and negative electrode prepared above are laminated, and after lamination, a gel electrolyte is injected. The gel electrolyte is composed of a polymer monomer PEGMA with a mass percentage of 2 wt%, an initiator AIBN with a mass percentage of 1 wt%, and a conventional electrolyte with a mass percentage of 97 wt%.

[0096] (4)Gradient curing

[0097] The quasi-solid-state battery after the above-mentioned electrolyte injection is first cured at 45 °C for 8 h, and then cured at 65 °C for 8 h to obtain the final quasi-solid-state battery.

[0098] Example 3

[0099] This example provides a method for preparing a quasi-solid-state battery, and the specific steps are as follows:

[0100] (1)Preparation of integrated positive electrode

[0101] Positive electrode mixing and coating: Prepare a positive electrode slurry. The positive electrode slurry includes 58% of the main raw materials and 42% of the solvent DMF by mass percentage. The main raw materials include the following components by mass percentage: lithium iron phosphate 92.7 wt%, conductive agent SP 2.15 wt%, binder PVDF 1.7 wt%, lithium hexafluorophosphate 1.4 wt%, polymer monomer PEGMA 1.0 wt%, solid-state electrolyte LATP 1 wt%, initiator AIBN 0.05 wt%. The prepared positive electrode slurry is coated on the positive electrode foil. During coating, the flow rate of the conveyor belt is adjusted to 2.5 m / s to complete curing during the coating process.

[0102] Solid-state electrolyte slurry coating: Prepare a solid-state electrolyte slurry. The solid-state electrolyte slurry includes 20% of the main raw materials and 80% of the solvent DMF by mass percentage. The main raw materials include the following components by mass percentage: lithium hexafluorophosphate 2.5 wt%, polymer monomer PEGMA 3 wt%, solid-state electrolyte LATP 65 wt%, initiator AIBN 0.5 wt%, binder PVDF-HFP 29 wt%. The prepared positive electrode slurry is coated on the positive electrode foil. During coating, the flow rate of the conveyor belt is adjusted to 2 m / s to complete curing during the coating process.

[0103] Separator Slurry Coating: Prepare an organic-inorganic composite solid electrolyte slurry. The organic-inorganic composite solid electrolyte slurry includes 30% by mass of the main raw materials and 70% by mass of the solvent DMF. The main raw materials include the following components by mass percentage: organic separator material PVDF-TRFE-CTFE 19wt%, inorganic separator material LATP 73wt%, lithium hexafluorophosphate 3wt%, polymer monomer PEGMA 4.92wt%, and initiator AIBN 0.08wt%. Coat the prepared positive electrode slurry on the aluminum foil of the positive electrode plate. During coating, adjust the flow rate of the conveyor belt to 2 m / s to complete curing during the coating process.

[0104] (2)Preparation of the negative electrode

[0105] Negative Electrode Mixing and Coating: Prepare a negative electrode slurry, and the components and contents are as follows: graphite 45wt%, binder 2.8wt%, conductive agent SP 1wt%, and water 51.2wt%. Coat the prepared negative electrode slurry on the copper foil and cure it in an oven to obtain the negative electrode.

[0106] (3)Preparation of the quasi-solid-state battery

[0107] Stack the integrated positive electrode and negative electrode prepared above, and inject the gel electrolyte after stacking. The gel electrolyte is composed of 2wt% of the polymer monomer PEGMA by mass percentage, 1wt% of the initiator AIBN by mass percentage, and 97wt% of the conventional electrolyte by mass percentage.

[0108] (4)Gradient Curing

[0109] The quasi-solid-state battery after the above injection is first cured at 60 °C for 5 h, and then cured at 80 °C for 3 h to obtain the final quasi-solid-state battery.

[0110] Example 4

[0111] This example provides a method for preparing a quasi-solid-state battery, and the specific steps are as follows:

[0112] (1)Preparation of the integrated positive electrode

[0113] Positive electrode mixing and coating: Prepare the positive electrode slurry. The positive electrode slurry includes 58% by mass of the main raw materials and 42% by mass of the solvent DMF. The main raw materials include the following components by mass percentage: lithium iron phosphate 91.7 wt%, conductive agent SP 1.7 wt%, binder PVDF 1.7 wt%, lithium hexafluorophosphate 1.4 wt%, polymer monomer DOL 2.4 wt%, solid electrolyte LATP 1 wt%, initiator Al(OTf)3 0.1 wt%. Coat the prepared positive electrode slurry on the aluminum foil of the positive electrode tab. During coating, adjust the flow rate of the conveyor belt to 2.5 m / s to complete curing during the coating process.

[0114] Solid electrolyte slurry coating: Prepare the solid electrolyte slurry. The solid electrolyte slurry includes 20% by mass of the main raw materials and 80% by mass of the solvent DMF. The main raw materials include the following components by mass percentage: lithium hexafluorophosphate 2.9 wt%, polymer monomer DOL 1 wt%, solid electrolyte LATP 67 wt%, initiator Al(OTf)3 0.1 wt%, binder PVDF-HFP 29 wt%. Coat the prepared positive electrode slurry on the aluminum foil of the positive electrode tab. During coating, adjust the flow rate of the conveyor belt to 2 m / s to complete curing during the coating process.

[0115] Separator slurry coating: Prepare the organic-inorganic composite solid electrolyte slurry. The organic-inorganic composite solid electrolyte slurry includes 30% by mass of the main raw materials and 70% by mass of the solvent DMF. The main raw materials include the following components by mass percentage: organic separator material PVDF-TRFE-CTFE 37 wt%, inorganic separator material LATP 55 wt%, lithium hexafluorophosphate 3 wt%, polymer monomer DOL 4.95 wt%, initiator Al(OTf)3 0.05 wt%. Coat the prepared positive electrode slurry on the aluminum foil of the positive electrode tab. During coating, adjust the flow rate of the conveyor belt to 2 m / s to complete curing during the coating process.

[0116] (2)Preparation of the negative electrode

[0117] Negative electrode mixing and coating: Prepare the negative electrode slurry. The components and contents are as follows: graphite 45 wt%, binder 2.8 wt%, conductive agent SP 1 wt%, water 51.2 wt%. Coat the prepared negative electrode slurry on the copper foil and cure it in an oven to obtain the negative electrode.

[0118] (3)Preparation of the quasi-solid-state battery

[0119] The integrated positive electrode and negative electrode prepared above are laminated, and after lamination, a gel electrolyte is injected. The gel electrolyte is composed of a polymer monomer DOL with a mass percentage of 2 wt%, an initiator Al(OTf)3 with a mass percentage of 1 wt%, and a conventional electrolyte with a mass percentage of 97 wt%.

[0120] (4)Gradient curing

[0121] The quasi-solid-state battery after the above-mentioned injection is first cured at 50 °C for 5 h, and then cured at 75 °C for 3 h to obtain the final quasi-solid-state battery.

[0122] Example 5

[0123] This example provides a method for preparing a quasi-solid-state battery, and the specific steps are as follows:

[0124] (1)Preparation of integrated positive electrode

[0125] Positive electrode mixing and coating: Prepare a positive electrode slurry. The positive electrode slurry includes 58% of the main raw materials and 42% of the solvent DMF by mass percentage. The main raw materials include the following components by mass percentage: lithium iron phosphate 92.7 wt%, conductive agent SP 1.7 wt%, binder PVDF 1.7 wt%, lithium hexafluorophosphate 1.4 wt%, polymer monomer PEGMA 2.4 wt%, initiator AIBN 0.1 wt%. The prepared positive electrode slurry is coated on the aluminum foil of the positive electrode plate. During coating, the flow rate of the conveyor belt is adjusted to 2.5 m / s to complete curing during the coating process.

[0126] Solid-state electrolyte slurry coating: Prepare a solid-state electrolyte slurry. The solid-state electrolyte slurry includes 20% of the main raw materials and 80% of the solvent DMF by mass percentage. The main raw materials include the following components by mass percentage: lithium hexafluorophosphate 2.9 wt%, polymer monomer PEGMA 1 wt%, solid-state electrolyte LATP 48 wt%, initiator AIBN 0.1 wt%, binder PVDF-HFP 48 wt%. The prepared positive electrode slurry is coated on the aluminum foil of the positive electrode plate. During coating, the flow rate of the conveyor belt is adjusted to 2 m / s to complete curing during the coating process.

[0127] Separator Slurry Coating: Prepare an organic-inorganic composite solid electrolyte slurry. The organic-inorganic composite solid electrolyte slurry includes 30% by mass of the main raw materials and 70% by mass of the solvent DMF. The main raw materials include the following components by mass percentage: organic separator material PVDF-TRFE-CTFE 46wt%, inorganic separator material LATP 45wt%, lithium hexafluorophosphate 3wt%, polymer monomer PEGMA 5wt%, and initiator AIBN 1wt%. Coat the prepared positive electrode slurry on the aluminum foil of the positive electrode sheet. During coating, adjust the flow rate of the conveyor belt to 2 m / s to complete curing during the coating process.

[0128] (2) Preparation of the Negative Electrode

[0129] Negative Electrode Mixing and Coating: Prepare a negative electrode slurry, and the components and contents are as follows: graphite 45wt%, binder PVDF 2.8wt%, conductive agent SP 1wt%, and water 51.2wt%. Coat the prepared negative electrode slurry on the copper foil and cure it in an oven to obtain the negative electrode.

[0130] (3) Preparation of the Quasi-Solid-State Battery

[0131] Stack the integrated positive electrode and negative electrode prepared above. After stacking, inject the gel electrolyte. The gel electrolyte is composed of 2wt% of the polymer monomer PEGMA, 1wt% of the initiator AIBN, and 97wt% of the conventional electrolyte by mass percentage.

[0132] (4) Gradient Curing

[0133] The quasi-solid-state battery after the above injection is first cured at 50 °C for 5 h, and then cured at 75 °C for 3 h to obtain the final quasi-solid-state battery.

[0134] Example 6

[0135] This example provides a method for preparing a quasi-solid-state battery, and the specific steps are as follows:

[0136] (1) Preparation of the Integrated Positive Electrode

[0137] Positive electrode mixing and coating: Prepare the positive electrode slurry. The positive electrode slurry includes 58% by mass of the main raw materials and 42% by mass of the solvent DMF. The main raw materials include the following components by mass percentage: lithium iron phosphate 92.7 wt%, conductive agent SP 1.7 wt%, binder PVDF 1.7 wt%, lithium hexafluorophosphate 1.4 wt%, polymer monomer PEGMA 2.4 wt%, initiator AIBN 0.1 wt%. Coat the prepared positive electrode slurry on the aluminum foil of the positive electrode plate. During coating, adjust the flow rate of the conveyor belt to 2.5 m / s to complete curing during the coating process.

[0138] Solid-state electrolyte slurry coating: Prepare the solid-state electrolyte slurry. The solid-state electrolyte slurry includes 20% by mass of the main raw materials and 80% by mass of the solvent DMF. The main raw materials include the following components by mass percentage: lithium hexafluorophosphate 2.9 wt%, polymer monomer PEGMA 1 wt%, solid-state electrolyte LATP 48 wt%, initiator AIBN 0.1 wt%, binder PVDF-HFP 48 wt%. Coat the prepared positive electrode slurry on the aluminum foil of the positive electrode plate. During coating, adjust the flow rate of the conveyor belt to 2 m / s to complete curing during the coating process.

[0139] Separator slurry coating: Prepare the separator slurry. The separator slurry includes 30% by mass of the main raw materials and 70% by mass of the solvent DMF. The main raw materials include the following components by mass percentage: organic separator material PVDF-TRFE-CTFE 91 wt%, lithium hexafluorophosphate 3 wt%, polymer monomer PEGMA 5 wt%, initiator AIBN 1 wt%. Coat the prepared positive electrode slurry on the aluminum foil of the positive electrode plate. During coating, adjust the flow rate of the conveyor belt to 2 m / s to complete curing during the coating process.

[0140] (2) Preparation of the negative electrode

[0141] Negative electrode mixing and coating: Prepare the negative electrode slurry, and the components and contents are as follows: graphite 45 wt%, binder PVDF 2.8 wt%, conductive agent SP 1 wt%, water 51.2 wt%. Coat the prepared negative electrode slurry on the copper foil and cure it in an oven to obtain the negative electrode.

[0142] (3) Preparation of the quasi-solid-state battery

[0143] Stack the integrated positive electrode and negative electrode prepared above, and inject the gel electrolyte after stacking. The gel electrolyte consists of 2 wt% of the polymer monomer PEGMA, 1 wt% of the initiator AIBN, and 97 wt% of the conventional electrolyte by mass percentage.

[0144] (4) Gradient curing

[0145] The quasi-solid-state battery after the above-mentioned liquid injection is first cured at 50 °C for 5 h, and then cured at 75 °C for 3 h to obtain the final quasi-solid-state battery.

[0146] Example 7

[0147] This example provides a method for preparing a quasi-solid-state battery, and the specific steps are as follows:

[0148] (1) Preparation of the integrated positive electrode

[0149] Positive electrode mixing and coating: Prepare the positive electrode slurry. The positive electrode slurry includes 55% by mass of the main raw materials and 45% by mass of the solvent DMF. The main raw materials include the following components by mass percentage: 94.02 wt% of lithium iron phosphate, 1.7 wt% of conductive agent carbon nanotubes, 1.0 wt% of binder PVDF-HFP, 1.0 wt% of lithium bis(fluorosulfonyl)imide, 1.2 wt% of polymer monomer PEGMA, 1 wt% of solid electrolyte LLTO, and 0.08 wt% of initiator AIBN. Coat the prepared positive electrode slurry on the aluminum foil of the positive electrode sheet. During coating, adjust the flow rate of the conveyor belt to 2.5 m / s to complete curing during the coating process.

[0150] Solid electrolyte slurry coating: Prepare the solid electrolyte slurry. The solid electrolyte slurry includes 15% by mass of the main raw materials and 85% by mass of the solvent DMF. The main raw materials include the following components by mass percentage: 1.9 wt% of lithium bis(fluorosulfonyl)imide, 3.8 wt% of polymer monomer PEGMA, 69 wt% of solid electrolyte LLTO, 0.3 wt% of initiator AIBN, and 25 wt% of binder PVDF. Coat the prepared positive electrode slurry on the aluminum foil of the positive electrode sheet. During coating, adjust the flow rate of the conveyor belt to 2 m / s to complete curing during the coating process.

[0151] Separator slurry coating: Prepare the organic-inorganic composite solid electrolyte slurry. The organic-inorganic composite solid electrolyte slurry includes 35% by mass of the main raw materials and 65% by mass of the solvent DMF. The main raw materials include the following components by mass percentage: 41 wt% of organic separator material PVDF-TRFE-CTFE, 46 wt% of inorganic separator material LATP, 8 wt% of lithium bis(fluorosulfonyl)imide, 4.7 wt% of polymer monomer PEGMA, and 0.3 wt% of initiator AIBN. Coat the prepared positive electrode slurry on the aluminum foil of the positive electrode sheet. During coating, adjust the flow rate of the conveyor belt to 2 m / s to complete curing during the coating process.

[0152] (2) Preparation of the negative electrode

[0153] Negative electrode mixing and coating: Prepare a negative electrode slurry, with the components and contents as follows: graphite 45 wt%, binder PVDF 2.8 wt%, conductive agent SP 1 wt%, and water 51.2 wt%. Coat the prepared negative electrode slurry on copper foil and cure it in an oven to obtain the negative electrode.

[0154] (3) Preparation of quasi-solid-state battery

[0155] Stack the above-prepared integrated positive electrode and negative electrode, and inject the gel electrolyte after stacking. The gel electrolyte consists of 2 wt% of polymer monomer PEGMA, 1 wt% of initiator AIBN, and 97 wt% of conventional electrolyte by mass percentage.

[0156] (4) Gradient curing

[0157] Cure the above-injected quasi-solid-state battery at 50 °C for 5 h first, and then cure it at 75 °C for 3 h to obtain the final quasi-solid-state battery.

[0158] Comparative example 1

[0159] This comparative example provides a method for preparing a quasi-solid-state battery, and the specific steps are as follows:

[0160] (1) Preparation of integrated positive electrode

[0161] Positive electrode mixing and coating: Prepare a positive electrode slurry. The positive electrode slurry includes 58% of the main raw material and 42% of the solvent DMF by mass percentage. The main raw material includes the following components by mass percentage: lithium iron phosphate 94.9 wt%, conductive agent SP 1.8 wt%, binder PVDF 1.8 wt%, and lithium hexafluorophosphate 1.5 wt%. Coat the prepared positive electrode slurry on the positive electrode tab aluminum foil, and adjust the flow rate of the conveyor belt to 2.5 m / s during coating. After coating, heat to volatilize the solvent.

[0162] Solid-state electrolyte slurry coating: Prepare a solid-state electrolyte slurry. The solid-state electrolyte slurry includes 20% of the main raw material and 80% of the solvent DMF by mass percentage. The main raw material includes the following components by mass percentage: lithium hexafluorophosphate 3.0 wt%, solid-state electrolyte LATP 48.5 wt%, and binder PVDF-HFP 48.5 wt%. Coat the prepared positive electrode slurry on the positive electrode tab aluminum foil, and adjust the flow rate of the conveyor belt to 2 m / s during coating. After coating, heat to volatilize the solvent.

[0163] Separator Slurry Coating: Prepare an organic-inorganic composite solid electrolyte slurry. The organic-inorganic composite solid electrolyte slurry consists of 30% main raw materials and 70% solvent DMF by mass percentage. The main raw materials include the following components by mass percentage: 46 wt% organic separator material PVDF-TRFE-CTFE, 45 wt% inorganic separator material LATP, 3 wt% lithium hexafluorophosphate, 5 wt% polymer monomer PEGMA, and 1 wt% initiator AIBN. Coat the prepared positive electrode slurry on the aluminum foil of the positive electrode. During coating, adjust the flow rate of the conveyor belt to 2 m / s, and after coating, heat to volatilize the solvent.

[0164] (2) Preparation of the Negative Electrode

[0165] Negative Electrode Mixing and Coating: Prepare a negative electrode slurry, where the components and their contents are as follows: 45 wt% graphite, 2.8 wt% binder PVDF, 1 wt% conductive agent SP, and 51.2 wt% water. Coat the prepared negative electrode slurry on the copper foil and cure it in an oven to obtain the negative electrode.

[0166] (3) Preparation of the Quasi-Solid-State Battery

[0167] Stack the above-prepared integrated positive and negative electrodes, and then inject the gel electrolyte. The gel electrolyte consists of 2 wt% polymer monomer PEGMA, 1 wt% initiator AIBN, and 97 wt% conventional electrolyte by mass percentage.

[0168] (4) Gradient Curing

[0169] The above-injected quasi-solid-state battery is first cured at 50 °C for 5 h, and then cured at 75 °C for 3 h to obtain the final quasi-solid-state battery.

[0170] Performance Testing:

[0171] Perform the following performance tests on the above-prepared quasi-solid-state battery. The test method is as described below, and the test results are as Figure 1-8 and Table 1 below.

[0172] (1) First Coulombic Efficiency Test: After standing the obtained batteries at 25 °C for 4 h respectively, perform the first charge-discharge capacity test. The test conditions are: charge at 0.1C to 3.65V, stand for 3 min, and then discharge at 0.1C to 2.5V. Obtain the charge-discharge curves and record the first charge capacity per gram C0 at 3.65V and the first discharge capacity per gram D0 respectively. Calculate its first Coulombic efficiency (i.e., the first efficiency) according to D0 / C0.

[0173] (2)5℃ Charge and Discharge Energy Efficiency Test: After each of the obtained batteries was left standing at (5 ± 2)°C for 20 h, charge and discharge capacity tests were carried out. The test conditions were as follows: at (5 ± 2)°C, charge at a constant power of 0.5P until the battery charging cut-off condition was reached, then leave it standing for 10 min, and record the power, time, voltage, temperature, and charging energy; at (5 ± 2)°C, discharge at a constant power of 0.5P until the battery discharge cut-off condition was reached, then leave it standing for 10 min, and record the power, time, voltage, temperature, and discharge energy; the ratio of the discharge energy to the charging energy was the 5°C energy efficiency.

[0174] (3)Mass Energy Density Detection: Using a battery charge and discharge tester, the battery was charged at a constant current of 0.5C to 3.65V at 25°C, then charged at a constant voltage until the current dropped to 0.02C. After leaving it standing for 5 min, the battery was discharged at a constant current of 0.5C to 2.5V, and the discharge capacity Q of the battery was recorded. 放 and the discharge energy E 放 , the mass of the battery was weighed and recorded as W, and the mass energy density ED = E 放 / W.

[0175] (4)The rate performance test was carried out according to the following steps:

[0176] a) Initial discharge;

[0177] b) Charge at a constant power of Prc until the battery charging cut-off condition is reached, then leave it standing for 10 min, and record the power, time, voltage, temperature, and charging energy;

[0178] c) Discharge at a constant power of Prd until the battery discharge cut-off condition is reached, then leave it standing for 10 min, and record the power, time, voltage, temperature, and discharge energy;

[0179] d) Charge at a constant power of 2Prc until the battery charging cut-off condition is reached, then leave it standing for 10 min, and record the power, time, voltage, temperature, and charging energy;

[0180] e) Charge at a constant power of Prc until the battery charging cut-off condition is reached, then leave it standing for 10 min, and record the power, time, voltage, temperature, and charging energy;

[0181] f) Discharge at a constant power of 2Prd until the battery discharge cut-off condition is reached, then leave it standing for 10 min, and record the power, time, voltage, temperature, and discharge energy;

[0182] g) Discharge at a constant power of Prd until the battery discharge cut-off condition is reached, then leave it standing for 10 min, and record the power, time, voltage, temperature, and discharge energy;

[0183] h) Charge at a constant power of 2Prc until the battery charging cut-off condition is reached, then leave it standing for 10 min, and record the power, time, voltage, temperature, and charging energy;

[0184] i) The battery discharges at a constant power of 2 Prd until the battery discharge cut-off condition, and the power, time, voltage, temperature, and discharge energy are recorded.

[0185] Calculate the 2P energy efficiency based on the charging energy in step h) and the discharge energy in step i).

[0186] (4) Cycle performance test: Perform a cycle performance test on the battery prepared above at room temperature of 25°C. The test process is as follows. First, charge at a constant current of 1C to 3.65V, then charge at a constant voltage until the cut-off current is 0.05C, and finally discharge at a constant current of 1C to 2.5V. After 800 cycles, divide the discharge energy of 800 cycles by the average value of the discharge energy of the first 10 cycles to obtain the energy retention rate.

[0187] Table 1

[0188]

[0189] It can be seen from the above results that when a conductive polymer is introduced into the positive electrode slurry and the solid electrolyte slurry, the prepared quasi-solid-state battery has better interfacial contact, higher initial efficiency, and more excellent cycle performance and energy efficiency at low temperature.

[0190] It can be seen from the comparison between Example 5 and Example 6 that when an organic-inorganic composite solid electrolyte is further used as the separator, the prepared quasi-solid-state battery has a higher energy density, and the presence of inorganic particles can effectively prevent lithium dendrite penetration, and the cycle performance is more excellent.

[0191] It can also be seen from the above table that when both the positive electrode slurry and the solid electrolyte slurry contain polymer monomers and initiators, and an organic-inorganic hybrid separator is used, the 2P energy efficiency of the quasi-solid-state batteries prepared in Examples 1-4, 7 and Example 5 all meets the requirements of GB / T 36276-2023. And when a solid electrolyte is further introduced into the positive electrode slurry, the initial efficiency, energy density, 2P energy efficiency and low-temperature performance of the prepared quasi-solid-state battery are significantly better.

[0192] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An integrated positive electrode, characterized in that, It includes at least a positive electrode active layer and a solid electrolyte layer formed successively on the positive electrode sheet; The positive electrode active layer includes a positive electrode active material and a conductive polymer coated on the surface of the positive electrode active material; The solid electrolyte layer includes a solid electrolyte and a conductive polymer coated on the surface of the solid electrolyte.

2. The integrated positive electrode according to claim 1, wherein The polymerization raw materials of the conductive polymer include polymer monomers, and the polymer monomers are selected from one or more of poly(ethylene glycol) methyl ether methacrylate, polyethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol dimethyl ether, 1,3-dioxolane, and poly(ethylene glycol) methyl ether acrylate.

3. The integrated positive electrode according to claim 1 or 2, characterized in that, The integrated positive electrode further includes a separator, and the separator is an organic-inorganic hybrid separator.

4. The integrated positive electrode according to claim 3, characterized in that, In the organic-inorganic hybrid separator, the mass ratio of the organic separator material is 10-85%, and the mass ratio of the inorganic separator material is 10-85%; and / or The organic-inorganic hybrid separator further includes a conductive polymer.

5. A method for preparing the integrated positive electrode according to any one of claims 1-4, characterized in that, It includes the following steps: Coating a positive electrode paste on the positive electrode sheet to make the positive electrode active layer, wherein the positive electrode paste includes a positive electrode active material, a polymer monomer, and an initiator; Coating a solid electrolyte paste on the positive electrode active layer to make the solid electrolyte layer, wherein the solid electrolyte paste includes a solid electrolyte, a polymer monomer, and an initiator.

6. The preparation method according to claim 5, characterized in that The positive electrode paste includes a main raw material and a solvent. In the main raw material, the mass ratio of the polymer monomer is 0.5-5%, and the mass ratio of the initiator is 0.05-1%; and / or The solid electrolyte paste includes a main raw material and a solvent. In the main raw material, the mass ratio of the polymer monomer is 0.5-5%, and the addition amount of the initiator is 0.05-5%.

7. The preparation method according to claim 5, characterized in that, The main raw material of the positive electrode paste includes a positive electrode active material, a conductive agent, a binder, a lithium salt, a polymer monomer, a solid electrolyte, and an initiator. Among them, the mass ratio of the positive electrode active material is 90-95%, the mass ratio of the conductive agent is 1-5%, the mass ratio of the binder is 1-5%, the mass ratio of the lithium salt is 1-5%, the mass ratio of the polymer monomer is 0.5-5%, the mass ratio of the initiator is 0.05-1%, and the mass ratio of the solid electrolyte is 0.5-1.5%; and / or The main raw material of the solid electrolyte paste includes a solid electrolyte, a lithium salt, a binder, a polymer monomer, and an initiator. Among them, the mass ratio of the solid electrolyte is 45-70%, the mass ratio of the lithium salt is 1-5%, the mass ratio of the binder is 25-50%, the mass ratio of the polymer monomer is 0.5-5%, and the addition amount of the initiator is 0.05-5%.

8. The preparation method according to any one of claims 5-7, characterized in that, It further includes the step of coating a separator paste on the solid electrolyte layer to make a separator.

9. The preparation method according to claim 8, wherein The diaphragm slurry includes a main raw material and a solvent. The main raw material includes an organic diaphragm material, an inorganic diaphragm material, a lithium salt, a dissolved electrolyte monomer, and an initiator. The mass ratio of the organic diaphragm material is 10-85%, the mass ratio of the inorganic diaphragm material is 10-85%, the mass ratio of the lithium salt is 2-10%, the mass ratio of the polymer monomer is 5-10%, and the mass ratio of the initiator is 0.05-1%.

10. A quasi-solid-state battery, characterized in that, The quasi-solid-state battery includes the integrated positive electrode according to any one of claims 1-4 or the integrated positive electrode prepared by the preparation method according to any one of claims 5-9.

11. The quasi-solid-state battery according to claim 10, wherein The quasi-solid-state battery is further filled with a gel electrolyte. The gel electrolyte at least includes a polymer monomer, an initiator, and an electrolyte. The mass ratio of the polymer monomer is 0.5-5%, and the mass ratio of the initiator is 0.05-1%.

12. A method for preparing the quasi-solid-state battery according to claim 10 or 11, characterized in that, It includes the following steps: Coat the negative electrode slurry on the negative electrode plate, then stack it with the integrated positive electrode. After stacking, inject the gel electrolyte, and then perform in-situ polymerization and curing.

13. The preparation method of the quasi-solid-state battery according to claim 12, wherein During the in-situ polymerization and curing treatment, a gradient curing process is adopted.

14. The preparation method of the quasi-solid-state battery according to claim 13, wherein, The gradient curing process is: curing at 40-60°C for 1-12h and curing at 65-80°C for 2-8h.

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