Preparation method of lithium tin phosphorus sulfur solid-state battery

Abstract

The invention relates to a preparation method of a lithium tin phosphorus sulfur solid-state battery. The preparation method comprises the following steps: grinding and mixing phosphorus pentasulfide, tin disulfide, lithium sulfide, lithium chloride and an additive in an argon atmosphere, performing high-temperature calcination, and pressing into a sheet to obtain a lithium tin phosphorus sulfur solid electrolyte sheet; stirring lithium manganate, carbon black, a binder and a solvent into uniform slurry, coating an aluminum foil current collector with the slurry, and drying, rolling and forming to obtain a positive electrode; taking a lithium metal sheet as a negative electrode; in a glove box filled with argon, placing the lithium tin phosphorus sulfur solid electrolyte sheet between the positive electrode and the negative electrode, tightly attaching the positive electrode and the negative electrode, and packaging and sealing to obtain the lithium tin phosphorus sulfur solid battery; the additive is prepared by carrying out a reaction on epoxy acrylate, lithium carbamate, 9-ethyl-3-amino carbazole and a catalyst 1, 8-diazabicyclo undec-7-ene; the lithium tin phosphorus sulfur solid-state battery prepared by the invention has excellent ionic conductivity and cycle performance.

Description

Technical Field

[0001] The present invention relates to the technical field of solid-state batteries, and in particular to a preparation method of a lithium-tin-phosphorus-sulfur solid-state battery. Background Art

[0002] Solid-state batteries use solid electrolytes to replace liquid electrolytes, fundamentally solving safety problems such as liquid electrolyte leakage and combustion. Solid electrolytes have high mechanical strength and thermal stability, can effectively inhibit the growth of lithium dendrites, reduce the risk of battery short circuit, and improve the safety of the battery.

[0003] Solid electrolytes can better match with electrode materials with high specific capacity, and solid-state batteries can use thinner electrolyte layers and higher electrode compaction densities, providing the possibility to improve the energy density of the battery.

[0004] Chinese Patent CN119306192A: It relates to the field of new energy batteries, and specifically relates to a sulfide solid electrolyte, its preparation method and a battery. The preparation method includes the following steps: S1. Dissolve lithium sulfide and lithium halide in an anhydrous organic solvent to obtain a first material; dry the first material to obtain a first mixture; S2. Mix the first mixture with phosphorus sulfide to obtain a precursor; S3. Sinter the precursor.

[0005] Chinese Patent CN119400796A: It provides a sulfide composite solid cathode, its preparation method and an all-solid-state battery. The preparation method includes: (1) Coat a cathode slurry on at least one surface of a current collector, and after drying, obtain a cathode layer with a pore structure; (2) Coat a sulfide electrolyte dispersion on the surface of the cathode layer away from the current collector, so that the sulfide electrolyte dispersion penetrates into the pore structure of the cathode layer, and then dry; (3) Repeat steps (1) and (2) at least once, and then after drying and rolling, obtain the sulfide composite solid cathode; wherein, the sulfide electrolyte dispersion includes a sulfide electrolyte and a non-polar solvent, and the sulfide electrolyte and the non-polar solvent are not miscible.

[0006] Chinese Patent CN119400940A: It provides a solid electrolyte, its preparation method, a separator, a battery and an electricity-related device, relating to the technical field of lithium batteries. The solid electrolyte is a core-shell composite structure with LATP as the core and a Mg-Sn alloy as the shell coated on the outer surface of the core.

[0007] For the solid-state batteries prepared by the above patents and the prior art, the ionic conductivity is low, and the stability and cycling performance of the battery are poor. Summary of the Invention

[0008] To solve the above problems, the present invention provides a method for preparing a lithium-tin-phosphorus-sulfur solid-state battery, and its operation steps are as follows:

[0009] S1 Prepare raw materials: Prepare lithium sulfide, phosphorus pentasulfide, tin disulfide, and lithium chloride, and ensure the purity and dryness of the raw materials to avoid adverse effects of impurities and moisture on the battery performance;

[0010] S2 Mix and grind: Under an argon atmosphere, put 16 - 22 parts of phosphorus pentasulfide, 12 - 18 parts of tin disulfide, 17 - 23 parts of lithium sulfide, 0.2 - 2 parts of lithium chloride, and 0.1 - 0.5 parts of an additive into a ball mill for grinding and mixing to make the raw materials fully mixed and uniform, obtaining a mixed powder;

[0011] S3 Seal and calcine: Seal the mixed powder in an argon atmosphere, put it into a high-temperature furnace for calcination, and press it into a sheet to obtain a lithium-tin-phosphorus-sulfur solid-state electrolyte sheet;

[0012] S4 Prepare the positive electrode: After uniformly mixing 70 - 90 parts of lithium manganate, 1 - 5 parts of carbon black, and 1 - 5 parts of a binder, add 5 - 10 parts of a solvent and stir into a uniform slurry; then coat the slurry on an aluminum foil current collector, dry to remove the solvent, and roll it into shape to obtain the positive electrode;

[0013] S5 Prepare the negative electrode: Cut a lithium metal sheet into a suitable size and directly use it as the negative electrode;

[0014] S6 Assemble the battery: In a glove box filled with argon, place the lithium-tin-phosphorus-sulfur solid-state electrolyte sheet between the positive electrode and the negative electrode to ensure that the three are closely fitted; then encapsulate them in a battery case for encapsulation, and after sealing, obtain a lithium-tin-phosphorus-sulfur solid-state battery.

[0015] The rotation speed of the ball mill is 300 - 500 rpm, and the ball milling time is 20 - 30 h.

[0016] The temperature of the high-temperature calcination is 500 - 650 °C, and the time is 10 - 18 h.

[0017] The binder is one of polyvinylidene fluoride, polyvinyl fluoride, polytetrafluoroethylene, polyvinylidene fluoride, and polyvinyl alcohol.

[0018] The solvent is one of dimethyl sulfoxide, N,N-dimethylformamide, acetone, 1,3-dimethyl-2-imidazolidinone, N-methylpyrrolidone, and 1-methyl-2-pyrrolidone.

[0019] During the whole preparation process, the operation should be carried out in an anhydrous and oxygen-free environment to prevent the raw materials and products from reacting with moisture and oxygen in the air and affecting the battery performance.

[0020] The preparation method of the additive is as follows:

[0021] H1: By weight, add 48–100 parts of epoxy acrylate, 6–13 parts of lithium carbamate, 0.08–0.7 parts of 9-ethyl-3-aminocarbazole, and 0.7–2.7 parts of catalyst 1,8-diazabicycloundec-7-ene to 300–600 parts of solvent ethanol, stir and mix, and react at 60 - 70 °C for 2 - 4 hours;

[0022] H2: After the reaction is completed, cool the reaction solution, recover ethanol by vacuum distillation, and concentrate the product under vacuum to obtain the additive.

[0023] Reaction mechanism

[0024] The amino groups in lithium carbamate and 9-ethyl-3-aminocarbazole react with the epoxy groups in epoxy acrylate to form a compound with a specific structure through an amino-epoxy addition reaction.

[0025] Technical effects

[0026] A preparation method of a lithium tin phosphorus sulfur solid-state battery according to the present invention has the following remarkable effects compared with the prior art:

[0027] 1. Improve interface stability: The additive of the present invention can form a stable interface layer at the interface between the sulfide solid electrolyte and the electrode material, effectively inhibiting chemical reactions and side reactions at the interface, improving the interface stability, and thus extending the service life of the battery.

[0028] 2. Enhance ionic conduction performance: The addition of the additive can improve the microstructure of the sulfide solid electrolyte, promote the migration and conduction of ions, increase the ionic conductivity of the electrolyte, and further improve the charge and discharge performance of the battery.

[0029] 3. Good compatibility: The additive of the present invention has good compatibility with the sulfide solid electrolyte, can be evenly dispersed in the electrolyte, and will not have a negative impact on the original performance of the electrolyte.

[0030] 4. Simple preparation method: The preparation method of the additive of the present invention is simple, the reaction conditions are mild, easy to control, and suitable for large-scale industrial production. Specific embodiments

[0031] To further illustrate the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description in combination with examples and comparative examples:

[0032] 1. Lithium ion conductivity test: An electrochemical workstation is used for AC impedance testing to obtain the ionic conductivity.

[0033] 2. Cycling life test of the solid-state battery: At room temperature of 25 °C, within the test voltage range from 2.5 V (discharge cut-off voltage) to 4.2 V (charge cut-off voltage), the first-week charge and discharge test of the solid-state battery is carried out at a charge and discharge current rate of 0.1C / 0.1C; subsequently, the solid-state battery is charged and discharged for 3 weeks each at current rates of 0.2C / 0.2C, 0.5C / 0.5C, 1C / 1C, and 2C / 2C; finally, the charge and discharge cycle of the solid-state battery is carried out at a current rate of 0.5C / 0.5C. When the discharge capacity of the solid-state battery reaches 80% of the discharge capacity of the first cycle at 0.5C rate, the test stops, and the number of cycles at room temperature is recorded.

[0034] Example 1

[0035] A preparation method of a lithium-tin-phosphorus-sulfur solid-state battery, and its operation steps are as follows:

[0036] S1 Prepare raw materials: Prepare lithium sulfide, phosphorus pentasulfide, tin disulfide, and lithium chloride, and ensure the purity and dryness of the raw materials to avoid adverse effects of impurities and moisture on the battery performance;

[0037] S2 Mix and grind: Under an argon atmosphere, put 16 g of phosphorus pentasulfide, 12 g of tin disulfide, 17 g of lithium sulfide, 0.2 g of lithium chloride, and 0.1 g of additive into a ball mill for grinding and mixing to make the raw materials fully mixed and uniform, obtaining a mixed powder;

[0038] S3 Seal and calcine: Seal the mixed powder in an argon atmosphere, put it into a high-temperature furnace for calcination, and press it into a sheet to obtain a lithium-tin-phosphorus-sulfur solid-state electrolyte sheet;

[0039] S4 Positive electrode preparation: After mixing 70 g of lithium manganate, 1 g of carbon black, and 1 g of binder evenly, add 5 g of solvent and stir into a uniform slurry; then coat the slurry on an aluminum foil current collector, dry to remove the solvent, and roll it into shape to obtain a positive electrode;

[0040] S5 Negative electrode preparation: Cut the lithium metal sheet into a suitable size and directly use it as the negative electrode;

[0041] S6 Battery assembly: In a glove box filled with argon, place the lithium-tin-phosphorus-sulfur solid-state electrolyte sheet between the positive electrode and the negative electrode to ensure that the three are closely fitted; then encapsulate them in a battery case for encapsulation, and obtain a lithium-tin-phosphorus-sulfur solid-state battery after sealing.

[0042] The rotation speed of the ball mill is 300 rpm, and the ball milling time is 20 h.

[0043] The temperature of the high-temperature calcination is 500 °C, and the time is 10 h.

[0044] The binder is polyvinylidene fluoride.

[0045] The solvent described is dimethyl sulfoxide.

[0046] During the entire preparation process, operations should be carried out in an anhydrous and anaerobic environment to prevent the raw materials and products from reacting with moisture and oxygen in the air, which may affect the battery performance.

[0047] The preparation method of the additive described is as follows:

[0048] H1: Add 48 g of epoxy acrylate, 6 g of lithium carbamate, 0.08 g of 9-ethyl-3-aminocarbazole, and 0.7 g of catalyst 1,8-diazabicycloundec-7-ene to 300 g of solvent ethanol, stir and mix, and react at 60 °C for 2 hours;

[0049] H2: After the reaction is completed, cool the reaction solution, recover ethanol by vacuum distillation, and concentrate the product under vacuum to obtain the additive.

[0050] Example 2

[0051] A preparation method of a lithium-tin-phosphorus-sulfur solid-state battery, the operation steps of which are as follows:

[0052] S1 Prepare raw materials: Prepare lithium sulfide, phosphorus pentasulfide, tin disulfide, and lithium chloride, and ensure the purity and dryness of the raw materials to avoid adverse effects of impurities and moisture on the battery performance;

[0053] S2 Mix and grind: Under an argon atmosphere, put 18 g of phosphorus pentasulfide, 14 g of tin disulfide, 19 g of lithium sulfide, 1 g of lithium chloride, and 0.2 g of additive into a ball mill for grinding and mixing to make the raw materials fully mixed evenly to obtain a mixed powder;

[0054] S3 Seal and calcine: Seal the mixed powder in an argon atmosphere, put it into a high-temperature furnace for calcination, and press it into a sheet to obtain a lithium-tin-phosphorus-sulfur solid-state electrolyte sheet;

[0055] S4 Positive electrode preparation: After mixing 75 g of lithium manganate, 2 g of carbon black, and 2 g of binder evenly, add 6 g of solvent and stir into a uniform slurry; then coat the slurry on an aluminum foil current collector, dry to remove the solvent, and roll it into shape to obtain the positive electrode;

[0056] S5 Negative electrode preparation: Cut the lithium metal sheet into appropriate sizes and directly use it as the negative electrode;

[0057] S6 Battery assembly: In a glove box filled with argon, place the lithium-tin-phosphorus-sulfur solid-state electrolyte sheet between the positive electrode and the negative electrode to ensure that the three are closely attached; then encapsulate them in a battery case for encapsulation, and obtain a lithium-tin-phosphorus-sulfur solid-state battery after sealing.

[0058] The rotation speed of the ball mill described is 350 rpm, and the ball milling time is 24 h.

[0059] The temperature of the high-temperature calcination is 550 °C and the time is 12 h.

[0060] The binder is polyvinylidene fluoride.

[0061] The solvent is N,N-dimethylformamide.

[0062] During the whole preparation process, the operation should be carried out in an anhydrous and oxygen-free environment to prevent the raw materials and products from reacting with moisture and oxygen in the air, which may affect the battery performance.

[0063] The preparation method of the additive is as follows:

[0064] H1: Add 62 g of epoxy acrylate, 8 g of lithium carbamate, 0.2 g of 9-ethyl-3-aminocarbazole, and 1.5 g of catalyst 1,8-diazabicycloundec-7-ene to 400 g of solvent ethanol, stir and mix, and react at 65 °C for 3 hours;

[0065] H2: After the reaction is completed, cool the reaction solution, recover ethanol by vacuum distillation, and concentrate the product under vacuum to obtain the additive.

[0066] Example 3

[0067] A preparation method of a lithium tin phosphorus sulfur solid-state battery, and its operation steps are as follows:

[0068] S1 Prepare raw materials: Prepare lithium sulfide, phosphorus pentasulfide, tin disulfide, and lithium chloride, and ensure the purity and dryness of the raw materials to avoid adverse effects of impurities and moisture on the battery performance;

[0069] S2 Mix and grind: Under an argon atmosphere, put 20 g of phosphorus pentasulfide, 16 g of tin disulfide, 21 g of lithium sulfide, 1.5 g of lithium chloride, and 0.4 g of additive into a ball mill for grinding and mixing to make the raw materials fully mixed evenly to obtain a mixed powder;

[0070] S3 Seal and calcine: Seal the mixed powder in an argon atmosphere, put it into a high-temperature furnace for calcination, and press it into a sheet to obtain a lithium tin phosphorus sulfur solid-state electrolyte sheet;

[0071] S4 Positive electrode preparation: After uniformly mixing 85 g of lithium manganate, 4 g of carbon black, and 4 g of binder, add 8 g of solvent and stir into a uniform slurry; then coat the slurry on an aluminum foil current collector, dry to remove the solvent, and roll it into shape to obtain a positive electrode;

[0072] S5 Negative electrode preparation: Cut the lithium metal sheet into appropriate sizes and directly use it as the negative electrode;

[0073] S6 Battery Assembly: In a glove box filled with argon, place the lithium tin phosphorus sulfur solid electrolyte sheet between the positive electrode and the negative electrode, ensuring that the three are closely fitted; then encapsulate them in a battery case for encapsulation. After sealing, a lithium tin phosphorus sulfur solid battery is obtained.

[0074] The rotation speed of the ball mill described is 450 rpm, and the ball milling time is 28 h.

[0075] The temperature of the high-temperature calcination described is 600 °C, and the time is 16 h.

[0076] The binder described is polyvinylidene fluoride.

[0077] The solvent described is acetone.

[0078] During the entire preparation process described, operations should be carried out in an anhydrous and anaerobic environment to prevent the raw materials and products from reacting with moisture and oxygen in the air, which may affect the battery performance.

[0079] The preparation method of the additive described is as follows:

[0080] H1: Add 90 g of epoxy acrylate, 11 g of lithium carbamate, 0.5 g of 9-ethyl-3-aminocarbazole, and 2.3 g of catalyst 1,8-diazabicycloundec-7-ene to 500 g of solvent ethanol, stir and mix, and react at 65 °C for 3 hours;

[0081] H2: After the reaction is completed, cool the reaction solution, recover ethanol by vacuum distillation, and concentrate the product under vacuum to obtain the additive.

[0082] Example 4

[0083] A preparation method of a lithium tin phosphorus sulfur solid battery, and its operating steps are as follows:

[0084] S1 Prepare raw materials: Prepare lithium sulfide, phosphorus pentasulfide, tin disulfide, and lithium chloride, and ensure the purity and dryness of the raw materials to avoid impurities and moisture having an adverse effect on the battery performance;

[0085] S2 Mix and grind: Under an argon atmosphere, put 22 g of phosphorus pentasulfide, 18 g of tin disulfide, 23 g of lithium sulfide, 2 g of lithium chloride, and 0.5 g of additive into a ball mill for grinding and mixing to make the raw materials fully mixed and uniform, obtaining a mixed powder;

[0086] S3 Seal and calcine: Seal the mixed powder in an argon atmosphere, put it into a high-temperature furnace for calcination, and press it into a sheet to obtain a lithium tin phosphorus sulfur solid electrolyte sheet;

[0087] Preparation of the S4 positive electrode: After uniformly mixing 90 g of lithium manganate, 5 g of carbon black, and 5 g of binder, 10 g of solvent was added and stirred into a uniform slurry; then the slurry was coated on an aluminum foil current collector, dried to remove the solvent, and roll-pressed to obtain the positive electrode.

[0088] Preparation of the S5 negative electrode: The lithium metal sheet was cut into a suitable size and directly used as the negative electrode.

[0089] S6 Battery assembly: In a glove box filled with argon, the lithium tin phosphorus sulfur solid electrolyte sheet was placed between the positive electrode and the negative electrode to ensure tight fitting of the three; then they were encapsulated in a battery case for encapsulation, and after sealing, the lithium tin phosphorus sulfur solid battery was obtained.

[0090] The rotation speed of the ball mill is 500 rpm, and the ball milling time is 30 h.

[0091] The temperature of the high-temperature calcination is 650 °C, and the time is 18 h.

[0092] The binder is polytetrafluoroethylene.

[0093] The solvent is 1,3-dimethyl-2-imidazolidinone.

[0094] During the whole preparation process, operations should be carried out in an anhydrous and anaerobic environment to prevent the raw materials and products from reacting with moisture and oxygen in the air, which may affect the battery performance.

[0095] The preparation method of the additive is as follows:

[0096] H1: 100 g of epoxy acrylate, 13 g of lithium carbamate, 0.7 g of 9-ethyl-3-aminocarbazole, and 2.7 g of catalyst 1,8-diazabicycloundec-7-ene were added to 600 g of solvent ethanol, stirred and mixed, and reacted at 70 °C for 4 hours;

[0097] H2: After the reaction ended, the reaction solution was cooled, ethanol was recovered by vacuum distillation, and the product was concentrated under vacuum to obtain the additive.

[0098] Comparative Example 1

[0099] No additive was added, and the others were the same as in Example 1.

[0100] Comparative Example 2

[0101] Lithium carbamate was not added, and the others were the same as in Example 1.

[0102] Comparative Example 3

[0103] 9-Ethyl-3-aminocarbazole was not added, and the others were the same as in Example 1.

[0104]

[0105]

[0106] Through the data analysis of the examples and comparative examples, the lithium-tin-phosphorus-sulfur solid-state battery prepared by the present invention has excellent ionic conductivity and cycling performance.

[0107] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Although the present invention has been disclosed above with the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments by using the above-disclosed technical content within the scope of the technical solution of the present invention. However, as long as it does not depart from the content of the technical solution of the present invention, any brief modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A preparation method of a lithium tin phosphorus sulfur solid-state battery, the operation steps of which are as follows: S1 Prepare raw materials: Prepare lithium sulfide, phosphorus pentasulfide, tin disulfide, and lithium chloride, and ensure the purity and dryness of the raw materials to avoid adverse effects of impurities and moisture on the battery performance; S2 Mix and grind: Under an argon atmosphere, put 16-22 parts of phosphorus pentasulfide, 12-18 parts of tin disulfide, 17-23 parts of lithium sulfide, 0.2-2 parts of lithium chloride, and 0.1-0.5 parts of additive into a ball mill for grinding and mixing to make the raw materials fully mixed and uniform, obtaining a mixed powder; S3 Seal and calcine: Seal the mixed powder in an argon atmosphere, put it into a high-temperature furnace for calcination, and press it into a sheet to obtain a lithium tin phosphorus sulfur solid electrolyte sheet; S4 Positive electrode preparation: After uniformly mixing 70-90 parts of lithium manganate, 1-5 parts of carbon black, and 1-5 parts of binder, add 5-10 parts of solvent and stir into a uniform slurry; then coat the slurry on an aluminum foil current collector, dry to remove the solvent, and roll it into shape to obtain a positive electrode; S5 Negative electrode preparation: Cut a lithium metal sheet into a suitable size and directly use it as the negative electrode; S6 Battery assembly: In a glove box filled with argon, place the lithium tin phosphorus sulfur solid electrolyte sheet between the positive electrode and the negative electrode to ensure tight fitting of the three; then encapsulate them in a battery case for encapsulation, and obtain a lithium tin phosphorus sulfur solid-state battery after sealing.

2. The preparation method of a lithium-tin-phosphorus-sulfur solid-state battery according to claim 1, characterized in that: The rotation speed of the ball mill is 300-500 rpm, and the ball milling time is 20-30 h.

3. The preparation method of a lithium-tin-phosphorus-sulfur solid-state battery according to claim 1, characterized in that: The temperature of the high-temperature calcination is 500-650 °C, and the time is 10-18 h.

4. The preparation method of a lithium-tin-phosphorus-sulfur solid-state battery according to claim 1, characterized in that: The binder is one of polyvinylidene fluoride, polyvinyl fluoride, polytetrafluoroethylene, polytetrafluoroethylene, and polyvinyl alcohol.

5. The preparation method of a lithium-tin-phosphorus-sulfur solid-state battery according to claim 1, wherein: The solvent is one of dimethyl sulfoxide, N,N-dimethylformamide, acetone, 1,3-dimethyl-2-imidazolidinone, N-methylpyrrolidone, and 1-methyl-2-pyrrolidone.

6. The preparation method of a lithium-tin-phosphorus-sulfur solid-state battery according to claim 1, characterized in that: During the entire preparation process, the operation should be carried out in an anhydrous and oxygen-free environment to prevent the raw materials and products from reacting with moisture and oxygen in the air and affecting the battery performance.

7. The preparation method of a lithium-tin-phosphorus-sulfur solid-state battery according to claim 1, wherein: The preparation method of the additive is as follows: H1: By weight, put 48–100 parts of epoxy acrylate, 6–13 parts of lithium carbamate, 0.08–0.7 parts of 9-ethyl-3-aminocarbazole, and 0.7–2.7 parts of catalyst 1,8-diazabicycloundec-7-ene into 300–600 parts of solvent ethanol, stir and mix, and react at 60-70 °C for 2-4 hours; H2: After the reaction is completed, cool the reaction solution, recover ethanol by reduced pressure distillation, and concentrate the product under vacuum to obtain the additive.

Images