Lithium primary battery and preparation method therefor

Abstract

The present application provides a lithium primary battery and a preparation method therefor. The lithium primary battery comprises a positive electrode sheet and a negative electrode sheet. The positive electrode sheet comprises a positive electrode current collector, and a positive electrode active coating and an electrolyte layer which are sequentially arranged on at least one surface of the positive electrode current collector, wherein the positive electrode active coating comprises a positive electrode active material, a polymer solid electrolyte, an oxide solid electrolyte and a lithium salt, and the electrolyte layer comprises a polymer solid electrolyte and a lithium salt.

Description

A lithium primary battery and a preparation method thereof

[0001] This application claims priority to the Chinese patent application No. 2024106529417 filed on May 23, 2024 with the China Patent Office, the whole content of the above application is incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the technical field of batteries, in particular to a lithium primary battery and a preparation method thereof. BACKGROUND

[0003] The continuous consumption of fossil energy and the energy crisis and environmental problems caused by non-renewable energy are becoming increasingly serious, and efficient and stable energy conversion and storage devices are attracting much attention. Lithium batteries have the advantages of high energy density and have become the most widely used electrochemical energy storage devices and are widely used in various fields. Lithium primary batteries have the advantages of good storage, stable discharge performance, high energy density, and are widely used in military supplies, outdoor equipment and other fields. TECHNICAL PROBLEM

[0004] Traditional lithium primary batteries usually use organic liquid as electrolyte, but the flammable and corrosive problems of organic electrolyte greatly limit the practical application of lithium primary batteries. Moreover, due to the small size of the lithium primary battery, the injection process is difficult to operate, and the injection amount of electrolyte is prone to be too much or too little, which ultimately leads to low consistency and production yield of the prepared lithium primary battery and affects the service life and self-discharge of the lithium primary battery. TECHNICAL SOLUTION

[0005] In a first aspect, the present application provides a lithium primary battery, which comprises a positive electrode sheet and a negative electrode sheet, the positive electrode sheet comprises a positive electrode current collector and a positive electrode active coating and an electrolyte layer which are sequentially arranged on at least one surface of the positive electrode current collector, the positive electrode active coating comprises a positive electrode active material, a polymer solid electrolyte, an oxide solid electrolyte and a lithium salt, and the electrolyte layer comprises a polymer solid electrolyte and a lithium salt; the polymer solid electrolyte comprises at least one of polyethylene oxide (PEO), polycarbonate (PPC), polyacrylonitrile (PAN), polysiloxane (PDMS) and polymethyl acrylate (PMMA); the oxide solid electrolyte comprises Li 1.5 Al 0.5 Ge 1.5 (PO4)3(LAGP), Li 1.4 Al 0.4 Ti 1.6 (PO4)3(LATP), perovskite ceramic Li 0.33 La 0.557TiO3 (LLTO), lithium lanthanum zirconium oxide Li7La3Zr2O 12 (LLZO).

[0006] In a second aspect, the application provides a preparation method of a lithium primary battery, comprising the following steps:

[0007] S1. Preparing a mixed solution by using a polymer solid electrolyte, an oxide solid electrolyte and a solvent;

[0008] S2. Preparing a positive electrode slurry by using a positive electrode active material, a conductive agent, a binder and a solvent;

[0009] S3. Mixing the mixed solution, the positive electrode slurry and a lithium salt uniformly and coating on at least one surface of a positive electrode current collector to form a positive electrode active coating layer;

[0010] S4. Preparing an electrolyte solution by using a polymer solid electrolyte, a lithium salt, a plasticizer and a solvent;

[0011] S5. Coating the electrolyte solution on the surface of the positive electrode active coating layer to form an electrolyte layer, thereby obtaining a positive electrode sheet;

[0012] S6. Assembling the positive electrode sheet and a negative electrode sheet to obtain a lithium primary battery;

[0013] The polymer electrolyte comprises at least one of polyethylene oxide, polycarbonate, polyacrylonitrile, polysiloxane, polyvinylidene fluoride and polymethacrylate.

[0014] The oxide solid electrolyte comprises at least one of Li 1.5 Al 0.5 Ge 1.5 (PO4)3, Li 1.4 Al 0.4 Ti 1.6 (PO4)3, Li 0.33 La 0.557 TiO3, Li7La3Zr2O 12 (LLZO). Advantages

[0015] (1) The application introduces polymer solid electrolyte and oxide solid electrolyte into the positive active coating of the positive electrode sheet, and composites an electrolyte layer containing polymer solid electrolyte on the surface of the positive active coating, and applies the positive electrode sheet to the lithium primary battery. On the one hand, the lithium primary battery is a solid-state battery, which eliminates the liquid injection process, improves the safety performance and energy density of the lithium primary battery, and also solves the problem of liquid injection difficulty in the preparation process of the traditional lithium primary battery, improves the production efficiency, and on the other hand, the positive active coating contains polymer solid electrolyte, oxide solid electrolyte and lithium salt, and the electrolyte layer arranged on the surface of the positive active coating contains polymer solid electrolyte. By introducing polymer solid electrolyte into the positive active coating of the positive electrode sheet and the electrolyte layer composite on the surface of the positive active coating, the interface compatibility of the electrolyte layer and the electrode can be effectively improved, so that the electrolyte layer and the electrode are in close contact, the service life of the lithium primary battery is prolonged, and the self-discharge of the lithium primary battery is reduced.

[0016] (2) The preparation method of the lithium primary battery of the application coats the positive electrode slurry containing polymer solid electrolyte and oxide solid electrolyte on the surface of the positive electrode current collector to form a positive active coating, then coats the electrolyte solution containing polymer solid electrolyte on the surface of the positive active coating to form an electrolyte layer, and assembles the prepared positive electrode sheet and negative electrode sheet. The electrolyte layer is tightly combined with the positive active coating in the positive electrode sheet and the negative electrode sheet, so that the service life of the lithium primary battery is prolonged, the self-discharge of the lithium primary battery is reduced, and the liquid injection process is eliminated in the preparation process of the above-mentioned lithium primary battery, effectively solving the problem of liquid injection difficulty in the preparation process of the traditional lithium primary battery, and improving the production efficiency. Embodiments of the application

[0017] In some embodiments, the thickness of the positive active coating is 50-150 μm.

[0018] In some embodiments, the thickness of the electrolyte layer is 6-30 μm.

[0019] In some embodiments, the polymer solid electrolyte is PEO, and the oxide solid electrolyte is LATP.

[0020] In some embodiments, the positive active material includes manganese dioxide, CF x (0.5 < x < 1).

[0021] In some embodiments, the positive current collector is a carbon-coated aluminum foil.

[0022] The carbon-coated aluminum foil is used as the positive electrode current collector, which has better conductivity, and can improve the contact interface between the aluminum foil and the positive electrode active coating, improve the adhesion between the positive electrode active coating and the aluminum foil, and further improve the energy density of the lithium primary battery and prolong the service life of the lithium primary battery.

[0023] In some embodiments, the positive electrode active coating further comprises a conductive agent and a binder; the conductive agent comprises at least one of graphite, carbon nanotubes, acetylene black, and conductive carbon black; and the binder comprises at least one of polyvinylidene fluoride (PVDF) and polyvinylidene fluoride-hexafluoropropylene copolymer.

[0024] In some embodiments, in the positive electrode active coating, the mass ratio of the positive electrode active material: the polymer solid-state electrolyte: the oxide solid-state electrolyte: the lithium salt is 75-85: 5-10: 1-5: 1-3.

[0025] In some embodiments, the conductive agent is mixed by carbon nanotubes and graphite in a mass ratio of 1-3: 1-2.

[0026] In some embodiments, the negative electrode sheet is a lithium metal foil, and the thickness of the lithium metal foil is 30-80 μm.

[0027] In some embodiments, the electrolyte layer further comprises a plasticizer, and the plasticizer comprises at least one of succinonitrile, acetonitrile, and polyethylene glycol dimethyl ether; and in the electrolyte layer, the mass ratio of the polymer solid-state electrolyte: the plasticizer: the lithium salt is 40-80: 5-10: 20-60.

[0028] By introducing the plasticizer into the electrolyte layer, the ionic conductivity of the electrolyte layer can be further improved.

[0029] In some embodiments, in S1, the solid content of the mixed solution is 10-30%.

[0030] In some embodiments, the solvent comprises at least one of N-methyl pyrrolidone (NMP), dimethyl sulfoxide (DMSO), dimethyl formamide (DMF), anisole, and p-xylene.

[0031] In some embodiments, the lithium salt comprises at least one of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (AsF6Li), lithium bisdifluorosulfonimide (LiFSI), lithium bis-trifluoromethylsulfonimide (LiTFSI), lithium bisoxalate borate (C4BLi3O 11 ), lithium difluoro(oxalato)borate (LiODFB), and lithium bis(oxalato)borate (LiBOB).

[0032] In some embodiments, in the positive electrode active coating, the positive electrode active material: conductive agent: binder: polymer solid electrolyte: oxide solid electrolyte: lithium salt = 75~85: 3~4: 2~3: 5~10: 1~5: 1~3 in terms of mass ratio.

[0033] Example 1

[0034] A lithium primary battery is prepared by the following steps:

[0035] S1. Under the conditions of temperature 25±5℃ and humidity 65±5%, the polymer solid electrolyte PEO, the oxide solid electrolyte LATP and the solvent NMP are respectively subjected to water removal treatment in advance to a water content of each component ≤20ppm, and then mixed uniformly to prepare a mixed solution with a solid content of 20%;

[0036] S2. Under the conditions of temperature 25±5℃ and humidity 65±5%, the positive electrode active material manganese dioxide, the conductive agent, the binder PVDF and the solvent NMP are respectively subjected to water removal treatment in advance to a water content of each component ≤20ppm, the binder PVDF and the solvent NMP are mixed uniformly to prepare a binder solution with a solid content of 7%, and then the positive electrode active material manganese dioxide and the conductive agent are dissolved in the binder solution and mixed uniformly to prepare a positive electrode slurry;

[0037] The conductive agent is mixed by carbon nanotubes and graphite in a mass ratio of 1:1;

[0038] S3. After the above mixed solution and the above positive electrode slurry are mixed uniformly, the lithium salt LiTFSI is added, stirred uniformly, coated on the two surfaces of the positive electrode current collector carbon-coated aluminum foil, and dried at a temperature of 90±5℃ for 24±2 hours to form a positive electrode active coating with a thickness of 100μm on each surface;

[0039] In S1, S2 and S3, the positive electrode active material: conductive agent: binder: polymer solid electrolyte: oxide solid electrolyte: lithium salt = 80: 3.5: 2.5: 8: 3: 2 in terms of mass ratio.

[0040] S4. Under the conditions of dew point temperature 25±5℃ and humidity 65±5%, the polymer solid electrolyte PEO, the lithium salt LiTFSI, the plasticizer acetonitrile and the solvent NMP are respectively subjected to water removal treatment in advance to a water content of each component ≤20ppm, the polymer solid electrolyte PEO, the lithium salt LiTFSI and the plasticizer acetonitrile are fully mixed, and then the solvent NMP is added and mixed uniformly to prepare an electrolyte solution;

[0041] The polymer solid electrolyte: plasticizer: lithium salt = 60: 8: 30 in terms of mass ratio.

[0042] S5. Coating the electrolyte solution on the surface of the positive active coating and drying at a temperature of 90±5℃ for 24±2 hours to form an electrolyte layer with a thickness of 15μm, to obtain a positive electrode sheet;

[0043] S6. Assembling the above positive electrode sheet after cutting and a negative electrode sheet of lithium metal sheet to obtain a lithium primary battery, wherein the electrolyte layer is tightly attached to the negative electrode sheet.

[0044] Example 2

[0045] A lithium primary battery is prepared by the following steps:

[0046] S1. Under the conditions of a temperature of 25±5℃ and a humidity of 65±5%, the polymer solid-state electrolyte PEO, the oxide solid-state electrolyte LATP, and the solvent NMP are separately subjected to water removal treatment in advance until the water content of each component is ≤20ppm, and then mixed uniformly to obtain a mixed solution with a solid content of 10%;

[0047] S2. Under the conditions of a temperature of 25±5℃ and a humidity of 65±5%, the positive active material manganese dioxide, the conductive agent, the binder PVDF, and the solvent NMP are separately subjected to water removal treatment in advance until the water content of each component is ≤20ppm, the binder PVDF and the solvent NMP are mixed uniformly to obtain a binder solution with a solid content of 7-10%, and then the positive active material manganese dioxide and the conductive agent are dissolved in the binder solution and mixed uniformly to obtain a positive electrode slurry;

[0048] The conductive agent is obtained by mixing carbon nanotubes and graphite in a mass ratio of 1:2.

[0049] S3. The above mixed solution and the above positive electrode slurry are mixed uniformly, then lithium salt LiTFSI is added, stirred uniformly, and then coated on the two surfaces of the positive electrode current collector carbon-coated aluminum foil and dried at a temperature of 90±5℃ for 24±2 hours to form positive active coatings with a thickness of 150μm on the two surfaces respectively;

[0050] In S1, S2, and S3, the positive active material: conductive agent: binder: polymer solid-state electrolyte: oxide solid-state electrolyte: lithium salt = 75:3:3:10:1:1 in terms of mass ratio.

[0051] S4. Under the conditions of a dew point temperature of 25±5℃ and a humidity of 65±5%, the polymer solid-state electrolyte PEO, the lithium salt LiTFSI, the plasticizer acetonitrile, and the solvent NMP are separately subjected to water removal treatment in advance until the water content of each component is ≤20ppm, the polymer solid-state electrolyte PEO, the lithium salt LiTFSI, and the plasticizer acetonitrile are mixed thoroughly, then the solvent NMP is added, and mixed uniformly to obtain an electrolyte solution;

[0052] Wherein, the polymer solid electrolyte: plasticizer: lithium salt = 40:5:20 in terms of mass ratio;

[0053] S5. The electrolyte solution is coated on the surface of the positive active coating and dried at a temperature of 90±5℃ for 24±2 hours to form an electrolyte layer with a thickness of 6μm, and a positive electrode sheet is prepared;

[0054] S6. The above positive electrode sheet is cut and assembled with a negative electrode sheet of lithium metal to prepare a lithium primary battery, wherein the electrolyte layer is tightly attached to the negative electrode sheet.

[0055] Example 3

[0056] A lithium primary battery is prepared by the following steps:

[0057] S1. Under the conditions of a temperature of 25±5℃ and a humidity of 65±5%, the polymer solid electrolyte PEO, the oxide solid electrolyte LATP, and the solvent NMP are separately subjected to water removal treatment to a water content of each component ≤20ppm, and then mixed uniformly to prepare a mixed solution with a solid content of 30%;

[0058] S2. Under the conditions of a temperature of 25±5℃ and a humidity of 65±5%, the positive active material manganese dioxide, the conductive agent, the binder PVDF, and the solvent NMP are separately subjected to water removal treatment to a water content of each component ≤20ppm, the binder PVDF and the solvent NMP are mixed uniformly to prepare a binder solution with a solid content of 7~10%, and then the positive active material manganese dioxide and the conductive agent are dissolved in the binder solution and mixed uniformly to prepare a positive electrode slurry;

[0059] Wherein, the conductive agent is composed of carbon nanotubes and graphite mixed in a mass ratio of 3:1;

[0060] S3. The above mixed solution and the above positive electrode slurry are mixed uniformly, then the lithium salt LiTFSI is added, stirred uniformly, and coated on both surfaces of the positive electrode current collector carbon-coated aluminum foil and dried at a temperature of 90±5℃ for 24±2 hours to form a positive active coating with a thickness of 50μm on both surfaces;

[0061] In S1, S2, and S3, the positive active material: conductive agent: binder: polymer solid electrolyte: oxide solid electrolyte: lithium salt = 85:4:2:5:5:3 in terms of mass ratio.

[0062] S4. Under the conditions of a dew point temperature of 25±5℃ and a humidity of 65±5%, the compound solid electrolyte PEO, lithium salt LiTFSI, plasticizer acetonitrile, and solvent NMP are respectively subjected to water removal treatment to a water content of each component ≤20 ppm. The polymer solid electrolyte PEO, lithium salt LiTFSI, and plasticizer acetonitrile are fully mixed, and then the solvent NMP is added and mixed uniformly to prepare an electrolyte solution;

[0063] wherein, according to the mass ratio, the polymer solid electrolyte: plasticizer: lithium salt = 80:10:60;

[0064] S5. The electrolyte solution is coated on the surface of the positive active coating layer and dried at a temperature of 90±5℃ for 24±2 hours to form an electrolyte layer with a thickness of 30 μm, thereby preparing a positive electrode sheet;

[0065] S6. The above positive electrode sheet is cut and assembled with a negative electrode sheet of lithium metal to prepare a lithium primary battery, wherein the electrolyte layer is tightly attached to the negative electrode sheet.

[0066] Example 4

[0067] This example provides a lithium primary battery. Compared with Example 1, the difference is that in the preparation steps S1 and S4 of the lithium primary battery, an equal amount of polymer solid electrolyte PPC is used instead of polymer solid electrolyte PEO. Except for the above difference, the materials, formula, and preparation operation used in this example are strictly consistent with those of Example 1.

[0068] Example 5

[0069] This example provides a lithium primary battery. Compared with Example 1, the difference is that in the preparation steps S1 and S4 of the lithium primary battery, an equal amount of polymer solid electrolyte PAN is used instead of polymer solid electrolyte PEO. Except for the above difference, the materials, formula, and preparation operation used in this example are strictly consistent with those of Example 1.

[0070] Example 6

[0071] This example provides a lithium primary battery. Compared with Example 1, the difference is that in the preparation steps S1 and S4 of the lithium primary battery, an equal amount of polymer solid electrolyte PDMS is used instead of polymer solid electrolyte PEO. Except for the above difference, the materials, formula, and preparation operation used in this example are strictly consistent with those of Example 1.

[0072] Example 7

[0073] The present example provides a lithium primary battery, which is compared with Example 1, the difference is that in the preparation step S4 of the lithium primary battery, the same amount of polymer solid electrolyte PVDF is used to replace the polymer solid electrolyte PEO. Except for the above difference, the materials, formula ratio and preparation operation used in the present example are strictly consistent with those of Example 1.

[0074] Example 8

[0075] The present example provides a lithium primary battery, which is compared with Example 1, the difference is that in the preparation steps S1 and S4 of the lithium primary battery, the same amount of polymer solid electrolyte PMMA is used to replace the polymer solid electrolyte PEO. Except for the above difference, the materials, formula ratio and preparation operation used in the present example are strictly consistent with those of Example 1.

[0076] Example 9

[0077] The present example provides a lithium primary battery, which is compared with Example 1, the difference is that in the preparation steps S1 and S4 of the lithium primary battery, the same amount of oxide solid electrolyte LAGP is used to replace the oxide solid electrolyte LATP. Except for the above difference, the materials, formula ratio and preparation operation used in the present example are strictly consistent with those of Example 1.

[0078] Example 10

[0079] The present example provides a lithium primary battery, which is compared with Example 1, the difference is that in the preparation step S1 of the lithium primary battery, the same amount of oxide solid electrolyte LLTO is used to replace the oxide solid electrolyte LATP. Except for the above difference, the materials, formula ratio and preparation operation used in the present example are strictly consistent with those of Example 1.

[0080] Example 11

[0081] The present example provides a lithium primary battery, which is compared with Example 1, the difference is that in the preparation step S1 of the lithium primary battery, the same amount of oxide solid electrolyte LLZO is used to replace the oxide solid electrolyte LATP. Except for the above difference, the materials, formula ratio and preparation operation used in the present example are strictly consistent with those of Example 1.

[0082] Example 12

[0083] The present example provides a lithium primary battery, which is compared with Example 1, and the difference is that: (1) in the preparation step S3 of the lithium primary battery, the thickness of the prepared positive active coating is 40 μm; (2) in the preparation step S5 of the lithium primary battery, the thickness of the prepared electrolyte layer is 3 μm. Except for the above differences, the materials, formula ratio and preparation operation used in the present example are strictly consistent with those of Example 1.

[0084] Example 13

[0085] The present example provides a lithium primary battery, which is compared with Example 1, and the difference is that: (1) in the preparation step S3 of the lithium primary battery, the thickness of the prepared positive active coating is 180 μm; (2) in the preparation step S5 of the lithium primary battery, the thickness of the prepared electrolyte layer is 40 μm. Except for the above differences, the materials, formula ratio and preparation operation used in the present example are strictly consistent with those of Example 1.

[0086] Example 14

[0087] The present example provides a lithium primary battery, which is compared with Example 1, and the difference is that: in the preparation step S3 of the lithium primary battery, the positive current collector uses an aluminum foil without a carbon coating instead of a carbon-coated aluminum foil. Except for the above difference, the materials, formula ratio and preparation operation used in the present example are strictly consistent with those of Example 1.

[0088] Example 15

[0089] The present example provides a lithium primary battery, which is compared with Example 1, and the difference is that: in the preparation step S4 of the lithium primary battery, an equal amount of lithium salt is used to replace the plasticizer. Except for the above difference, the materials, formula ratio and preparation operation used in the present example are strictly consistent with those of Example 1.

[0090] Example 16

[0091] The present example provides a lithium primary battery, which is compared with Example 1, and the difference is that: in the preparation step S2 of the lithium primary battery, an equal amount of positive active material CF x (0.5 < x < 1) is used to replace the positive active material manganese dioxide. Except for the above difference, the materials, formula ratio and preparation operation used in the present example are strictly consistent with those of Example 1.

[0092] Comparative Example 1

[0093] The present comparative example provides a lithium primary battery, which is compared with Example 1, and the difference is that in the preparation step S1 of the lithium primary battery, an equal amount of the polymer solid-state electrolyte PEO is used to replace the oxide solid-state electrolyte LATP. Except for the above difference, the materials, formula ratio and preparation operation used in the present comparative example are strictly consistent with those of Example 1.

[0094] Comparative Example 2

[0095] The present comparative example provides a lithium primary battery, which is compared with Example 1, and the difference is that in the preparation step S1 of the lithium primary battery, an equal amount of the oxide solid-state electrolyte LATP is used to replace the polymer solid-state electrolyte PEO. Except for the above difference, the materials, formula ratio and preparation operation used in the present comparative example are strictly consistent with those of Example 1.

[0096] Comparative Example 3

[0097] The present comparative example provides a lithium primary battery, which is compared with Example 1, and the difference is that (1) in the preparation step S1 of the lithium primary battery, an equal amount of the polymer solid-state electrolyte PEO is used to replace the oxide solid-state electrolyte LATP; (2) in the preparation step S3 of the lithium primary battery, the preparation process of the positive active coating does not contain lithium salt LiTFSI. Except for the above differences, the materials, formula ratio and preparation operation used in the present comparative example are strictly consistent with those of Example 1.

[0098] Test Example

[0099] 1. Test Subject

[0100] The lithium primary batteries prepared in Examples 1-16 and Comparative Examples 1-3 are used as test subjects, and relevant performance tests are carried out.

[0101] 2. Test Content

[0102] The self-discharge of the battery is an important parameter for characterizing the performance of the lithium primary battery. In the present test example, the self-discharge of the lithium primary battery is mainly tested by the static measurement method: under certain environmental conditions (temperature 85℃, humidity 85%), the lithium primary battery is placed for a long time, and the change of the open circuit voltage of the lithium primary battery before and after the static placement is measured to characterize the degree of self-discharge of the battery.

[0103] The annual self-discharge rate of the lithium primary battery is calculated according to the following formula: the open circuit voltage of the lithium primary battery is measured when the lithium primary battery is in a full charge state before static placement, which is denoted as V0, the open circuit voltage of the lithium primary battery is measured after 30 days of static placement under the conditions of temperature 85℃ and humidity 85%, which is denoted as V1, the self-discharge rate of the lithium primary battery for 30 days is η=[(V0-V1) / V0]x100%, and the annual self-discharge rate is calculated or converted according to the self-discharge rate of the lithium primary battery for 30 days.

[0104] 3. Experimental results

[0105] Table 1 Test results of annual self-discharge rate of lithium primary batteries

[0106] Group Annual self-discharge rate η (%) Example 1 2.0 Example 2 2.1 Example 3 2.5 Example 4 3.2 Example 5 3.5 Example 6 3.6 Example 7 3.8 Example 8 3.1 Example 9 3.3 Example 10 3.6 Example 11 3.4 Example 12 4.1 Example 13 3.9 Example 14 2.9 Example 15 4.2 Example 16 2.8 Comparative Example 1 4.6 Comparative Example 2 4.5 Comparative Example 3 4.8

[0107] The test results of the related performances of the lithium primary batteries provided by Examples 1-16 and Comparative Examples 1-3 are shown in Table 1.

[0108] The positive active coating layer of the positive electrode sheet of the lithium primary batteries provided by Examples 1-3 takes manganese dioxide as the positive active material and introduces the polymer solid electrolyte PEO, the oxide solid electrolyte LATP and the lithium salt LiTFSI, and at the same time, the electrolyte layer containing the polymer solid electrolyte PEO and the lithium salt LiTFSI is compounded on the surface of the positive active coating layer. The test results show that the annual self-discharge rate of the lithium primary batteries provided by Examples 1-3 is only 2.0-2.5%, and the low annual self-discharge rate can prolong the service life of the lithium primary batteries.

[0109] Compared with Example 1, the positive active coating layer of the positive electrode sheet of the lithium primary battery provided by Comparative Example 1 does not contain the oxide solid electrolyte LATP, the positive active coating layer of the positive electrode sheet of the lithium primary battery provided by Comparative Example 2 does not contain the polymer solid electrolyte PEO, and the positive active coating layer of the positive electrode sheet of the lithium primary battery provided by Comparative Example 3 does not contain the oxide solid electrolyte LATP and the lithium salt in the electrolyte layer. The test results show that the annual self-discharge rate of the lithium primary batteries provided by Comparative Examples 1, 2 and 3 is significantly higher than that of Example 1.

[0110] Compared with Example 1, the polymer solid electrolyte used in the positive active coating layer and the electrolyte layer of the positive electrode sheet of the lithium primary batteries provided by Examples 4, 5, 6 and 8 is PPC, PAN, PDMS and PMMA respectively, the polymer solid electrolyte used in the electrolyte layer of the positive electrode sheet of the lithium primary battery provided by Example 7 is PVDF, and the oxide solid electrolyte used in the positive active coating layer of the positive electrode sheet of the lithium primary batteries provided by Examples 9, 10 and 11 is LAGP, LLTO and LLZO respectively. The test results show that the annual self-discharge rate of the lithium primary batteries provided by Examples 4, 5, 6, 7, 8, 9, 10 and 11 is higher than that of Example 1.

[0111] Compared with Example 1, the thickness of the positive active coating of the positive electrode sheet of the lithium primary battery provided in Example 12 is <50 μm, and the thickness of the electrolyte layer is <6 μm, the thickness of the positive active coating of the positive electrode sheet of the lithium primary battery provided in Example 13 is >150 μm, and the thickness of the electrolyte layer is >30 μm, and the test results show that the annual self-discharge rates of the lithium primary batteries provided in Examples 12 and 13 are both higher than that of Example 1.

[0112] Compared with Example 1, the positive current collector used in the positive electrode sheet of the lithium primary battery provided in Example 14 is an aluminum foil without carbon coating, and the positive active material used in the positive electrode sheet of the lithium primary battery provided in Example 16 is CF x (0.5 < x < 1), and the test results show that the annual self-discharge rates of the lithium primary batteries provided in Examples 14 and 16 are slightly higher than that of Example 1; the electrolyte layer of the positive electrode sheet of the lithium primary battery provided in Example 15 does not contain plasticizer, and the test results show that the annual self-discharge rate of the lithium primary battery provided in Example 15 is significantly higher than that of Example 1.

Claims

1. A lithium primary battery, comprising a positive electrode sheet and a negative electrode sheet, the positive electrode sheet comprising a positive electrode current collector and a positive electrode active coating layer and an electrolyte layer sequentially disposed on at least one surface of the positive electrode current collector, the positive electrode active coating layer comprising a positive electrode active material, a polymer solid electrolyte, an oxide solid electrolyte and a lithium salt, the electrolyte layer comprising a polymer solid electrolyte and a lithium salt; the polymer solid electrolyte comprising at least one of polyethylene oxide, polycarbonate, polyacrylonitrile, polysiloxane, polymethacrylate; The oxide solid state electrolyte includes Li 1.5 Al 0.5 Ge 1.5 (PO4)3, Li 1.4 Al 0.4 Ti 1.6 (PO4)3, Li 0.33 La 0.557 TiO3, Li7La3Zr2O 12 at least one of.

2. The lithium primary battery according to claim 1, wherein: a thickness of the positive electrode active coating layer being 50-150 μm, and / or, a thickness of the electrolyte layer being 6-30 μm.

3. The lithium primary battery according to claim 1, wherein: The polymer solid-state electrolyte is polyethylene oxide, and the oxide solid-state electrolyte is Li 1.4 Al 0.4 Ti 1.6 (PO4)3.

4. The lithium primary battery according to claim 1, wherein: The positive active material includes manganese dioxide, CF x at least one of (0.5 < x ≤ 1).

5. The lithium primary battery according to claim 1, wherein: the positive electrode current collector being a carbon-coated aluminum foil.

6. The lithium primary battery according to claim 1, wherein: in the positive electrode active coating layer, the positive electrode active material: the polymer solid electrolyte: the oxide solid electrolyte: the lithium salt = 75-85: 5-10: 1-5: 1-3 by mass ratio.

7. The lithium primary battery according to claim 1, wherein: the negative electrode sheet being a lithium metal sheet.

8. The lithium primary battery according to claim 1, wherein: the electrolyte layer further comprising a plasticizer, the plasticizer comprising at least one of succinonitrile, acetonitrile, polyethylene glycol dimethyl ether; in the electrolyte layer, the polymer solid electrolyte: the plasticizer: the lithium salt = 40-80: 5-10: 20-60 by mass ratio. 9.A method for preparing a lithium primary battery, comprising the following steps: S1.preparing a mixed solution by using a polymer solid electrolyte, an oxide solid electrolyte and a solvent; S2.preparing a positive electrode slurry by using a positive electrode active material and a conductive agent, a binder and a solvent; S3.mixing the mixed solution, the positive electrode slurry and a lithium salt uniformly and coating on at least one surface of the positive electrode current collector to form a positive electrode active coating layer; S4.preparing an electrolyte solution by using a polymer solid electrolyte, a lithium salt, a plasticizer and a solvent; S5.coating the electrolyte solution on the surface of the positive electrode active coating layer to form an electrolyte layer, thereby preparing a positive electrode sheet; S6.assembling the positive electrode sheet and a negative electrode sheet to prepare the lithium primary battery; the polymer electrolyte comprising at least one of polyethylene oxide, polycarbonate, polyacrylonitrile, polysiloxane, polymethacrylate; The oxide solid state electrolyte includes Li 1.5 Al 0.5 Ge 1.5 (PO4)3, Li 1.4 Al 0.4 Ti 1.6 (PO4)3, Li 0.33 La 0.557 TiO3, Li7La3Zr2O 12 at least one of.

10. The method of producing a lithium primary battery according to claim 9, wherein: in the S1, a solid content of the mixed solution being 10-30%.