Method for preparing solid-state lithium-ion battery using 3D printing and obtained lithium-ion battery

Abstract

The present invention discloses a method for preparing a solid-state lithium-ion battery using 3D printing and the obtained lithium-ion battery, comprising the following steps: S1, preparing positive electrode ink, negative electrode ink and composite electrolyte ink; S2, placing the positive electrode ink in a 3D printer syringe, printing layer by layer on a glass substrate and simultaneously performing photocuring to obtain a 3D printed positive electrode; S3, placing the composite electrolyte ink in a 3D printer syringe, printing layer by layer on the surface of the positive electrode and simultaneously performing photocuring to obtain an electrolyte; S4, placing the negative electrode ink in a 3D printer syringe, printing layer by layer on the surface of the electrolyte and simultaneously performing photocuring; S5, printing and packaging the outer layer. The method of the present invention combines the advantages of ink direct writing molding and photocuring molding, can realize 3D printing integrated continuous preparation of solid-state batteries, improves the close bonding between the solid electrolyte and the electrode, does not require degreasing in the traditional photocuring process and does not require a large amount of additives, simplifies the formula and molding process, and the entire printing preparation process avoids the processes of current collector, binder, drying, pole piece compaction, assembly, thermal plastic sealing, etc. required in the traditional battery preparation process, greatly simplifying the preparation process.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium ion battery preparation, and in particular to a method for preparing a solid-state lithium ion battery using 3D printing and the obtained lithium ion battery. Background Art

[0002] With the rapid development of new energy vehicles and the growing demand for new energy storage in the power grid, it is becoming increasingly urgent to improve the energy density and safety performance of batteries. Traditional lithium-ion batteries mostly use liquid organic electrolytes, which are flammable and decompose under high pressure, resulting in poor battery safety performance. The emergence of solid-state batteries can effectively solve these shortcomings. They can significantly improve the energy density and safety performance of batteries and are an inevitable trend in the future development of lithium-ion batteries. For solid-state batteries, one of the technical difficulties is to improve the stability of the solid-solid interface between the electrolyte and the electrode and promote the ion migration rate. However, the traditional method of preparing solid-state batteries is to prepare the electrodes and electrolytes separately and then assemble them. This method is not only not conducive to improving the tightness of the solid-solid interface, resulting in increased interface impedance, but also the process is time-consuming.

[0003] The recent rise of 3D printing technology has revolutionized traditional planar electrode structures, enabling customizable complex three-dimensional electrode and solid-state electrolyte structures. This can significantly shorten lithium-ion migration distances and increase lithium-ion diffusion rates. However, the current 3D printing process for preparing lithium-ion batteries is complex. Typically, the positive and negative electrodes are printed separately and then assembled with the electrolyte in a glove box. This cumbersome and time-consuming process fails to fully utilize the advantages of 3D printing. Furthermore, the printing process requires the addition of various inactive forming agents, which can negatively impact the battery's electrochemical performance. For example, the highly sensitive photocuring technique requires the addition of large amounts of photosensitive resin materials. However, these materials are inherently non-conductive and require degreasing and demolding. Existing photocuring printing techniques generally have significant limitations in electrode and electrolyte preparation. Ink direct writing techniques, which are widely applicable, place high rheological demands on the ink, necessitating the addition of numerous forming agents to meet printing requirements. These additives often negatively impact electrode performance. Furthermore, the printing inks often contain significant amounts of water or other solvents, requiring subsequent freeze-drying or heat treatment to produce the final electrode, a complex process. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for preparing solid-state lithium-ion batteries using 3D printing and the lithium-ion batteries obtained in response to the above-mentioned problems. The present invention provides a 3D printing technology with a simple process and the ability to continuously prepare solid-state lithium-ion batteries in an integrated manner. It not only overcomes the defects of existing 3D printed lithium-ion batteries, but also eliminates the need for a large number of additives in traditional photocuring processes such as degreasing and direct writing processes, thus simplifying the molding ink formula and printing process. In addition, the solid-state lithium-ion battery obtained has a high degree of close bonding between the electrode and electrolyte interface, which reduces the solid-solid interface impedance, improves the lithium ion migration ability, and significantly improves the battery performance. The technical solution adopted by the present invention is as follows: A method for preparing solid-state lithium-ion batteries using 3D printing, comprising the following steps:

[0005] S1. Take the positive electrode, negative electrode and composite electrolyte ink and stir them evenly on a magnetic stirrer to obtain positive electrode ink, negative electrode ink and composite electrolyte ink respectively;

[0006] S2, placing the cathode ink in the syringe of a 3D printer, setting the printer parameters, printing layer by layer on a glass substrate and simultaneously performing light curing to obtain a 3D printed cathode;

[0007] S3, placing the composite electrolyte ink in the syringe of a 3D printer, setting the printer parameters, printing layer by layer on the surface of the positive electrode printed in S2 and simultaneously performing light curing to obtain an electrolyte that is tightly bonded to the positive electrode surface;

[0008] S4, placing the negative electrode ink in the syringe of the 3D printer, setting the printer parameters, printing layer by layer on the electrolyte surface printed in S3 and simultaneously performing light curing to obtain a negative electrode that is closely bonded to the electrolyte surface, and then obtaining a positive electrode / electrolyte / negative electrode battery structure;

[0009] S5. Peel the battery structure obtained in S4 off the glass plate, print and package the outer layer, and use photosensitive epoxy resin as the packaging material to obtain the battery structure.

[0010] In the present invention, on the one hand, the present invention can improve the close bonding between the solid electrolyte and the electrode, and the integrated molding technology is conducive to improving the electrode / electrolyte interface compatibility and promoting lithium ion migration. On the other hand, it combines the advantages of ink direct writing molding and photocuring molding technology. By improving the ink formula, there is no need for the subsequent sintering and degreasing process of the traditional photocuring process and no need for a large amount of non-electrochemically active additives in the direct writing process, which simplifies the molding ink formula and printing process, overcomes the application obstacles of 3D printing technology in solid-state lithium-ion batteries, and is conducive to process scale. In addition, the entire process avoids the current collector, binder, drying, pole piece compaction, assembly, thermal plastic sealing and other processes required in the traditional battery preparation process, realizes full-process 3D printing, greatly simplifies the preparation process, and the solid-state lithium-ion battery prepared by the method of the present invention has the advantages of high energy density and good cycle performance.

[0011] In the present invention, the present invention realizes the curing and forming of the positive electrode, the negative electrode and the composite electrolyte by photocuring, avoiding the use of a binder in the electrode, and there is no need to adopt subsequent processes such as sintering degreasing and compaction. In order to achieve this purpose, the positive electrode ink, the negative electrode ink and the composite electrolyte ink all contain a photocuring functional agent (the photocuring functional agent is added in a very small amount, and the following selected polymer monomer has no negative effect on lithium ion migration, and its effect on the electrochemical properties of the positive electrode, the negative electrode and the composite electrolyte is not obvious and can be ignored). The photocuring functional agent includes a polymer monomer and a photoinitiator, and the mass ratio of the polymer monomer to the photoinitiator is 50-150:1, for example, it can be 50:1, 55:1, 70:1, 80:1, 90:1, 100:1, 110:1, 115:1, 120:1, 125:1, 130:1, 150:1, etc.

[0012] Furthermore, the polymer monomer is selected from one or more of hydroxyethyl acrylate, trimethylolpropane triacrylate, polyethylene glycol methacrylate, polyethylene glycol diacrylate, methoxypolyethylene glycol methacrylate, cyclohexene oxide, ethoxylated trimethylolpropane triacrylate, methacrylate, and hexanediol diacrylate; and the photoinitiator is one or more of trimethylbenzoyl-diphenylphosphine oxide, 2-hydroxy-2-methyl 1-phenyl 1-propanone, 1-hydroxycyclohexyl phenyl ketone, 2,2-dihydroxymethylpropionic acid, and xylene ketone.

[0013] Furthermore, in terms of mass percentage, the positive electrode ink includes 1%-10% of a photocurable functional agent, 75%-90% of a positive electrode active material, 2%-10% of a conductive agent, and 1%-8% of a dispersant (the dispersant selected below is highly volatile and is added in a small amount, and is assisted in its volatilization by a subsequent heating pad, without the need for further drying and other processes). In the positive electrode ink of the present invention, the dosage of the photocurable functional agent can be specifically 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, etc., the dosage of the positive electrode active material can be specifically 75%, 80%, 85%, 90%, etc., the dosage of the conductive agent can be specifically 2%, 3%, 4%, 5%, 5.5%, 6%, 7%, 8%, 10%, etc., and the dosage of the dispersant can be adaptively adjusted according to actual needs without special requirements.

[0014] Furthermore, the positive electrode active material is selected from one or more of lithium cobalt oxide, lithium iron phosphate, lithium manganese oxide, nickel-cobalt-manganese ternary materials, nickel-cobalt-aluminum materials, and manganese-based lithium-rich materials; the conductive agent is selected from one or more of conductive carbon black, conductive graphite, carbon nanotubes, acetylene black, graphene, and carbon fibers; and the dispersant is selected from one or more of polyacrylic acid, acetonitrile, N-methylpyrrolidone, dimethylacetamide, ethanol, glycerol, ethylene carbonate, and propylene carbonate. Furthermore, the amount of photocurable functional agent added should be neither too high nor too low. Excessive addition can negatively impact the electrochemical performance of the material, while insufficient addition can prevent the electrode from fully curing and forming.

[0015] In the present invention, the negative electrode ink includes, by mass percentage, 1%-10% of a photocurable functional agent, 75%-90% of a negative electrode active material, 2%-10% of a conductive agent, and 1%-8% of a dispersant (the solvent selected below is highly volatile and is added in a small amount, and is assisted in its volatilization by a subsequent heating pad, without the need for a drying process). In the negative electrode ink, the amount of the photocurable functional agent can be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, etc., the amount of the negative electrode active material can be 75%, 80%, 85%, 90%, etc., the amount of the conductive agent can be 2%, 3%, 4%, 5%, 5.5%, 6%, 7%, 8%, 10%, etc., and the amount of the dispersant can be adaptively adjusted according to actual needs without special requirements.

[0016] Furthermore, the negative electrode active material is selected from one or more of graphite, silicon carbon, and lithium titanate; the conductive agent is selected from one or more of conductive carbon black, conductive graphite, carbon nanotubes, acetylene black, graphene, and carbon fibers; and the dispersant is selected from one or more of polyacrylic acid, acetonitrile, N-methylpyrrolidone, dimethylacetamide, ethanol, glycerol, ethylene carbonate, and propylene carbonate. Accordingly, the amount of photocurable functional agent added should be neither too high nor too low. Excessive addition can negatively impact the electrochemical performance of the material, while insufficient addition can prevent the electrode from fully curing.

[0017] In the present invention, the composite electrolyte ink includes, by mass percentage, 1%-10% of a photocurable functional agent, 45%-75% of a polymer, 1%-20% of a lithium salt, 1%-20% of an ion conductive powder, and 1%-10% of an organic solvent. In the composite electrolyte ink, the specific dosage of the photocurable functional agent can be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, etc., the specific dosage of the polymer can be 45%, 50%, 55%, 60%, 65%, 70%, 75%, etc., the specific dosage of the lithium salt can be 1%, 6%, 8%, 9%, 10%, 12%, 15%, 17%, 18%, 20%, etc., the specific dosage of the ion conductive powder can be 1%, 3%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, etc., and the dosage of the organic solvent can be adaptively adjusted according to actual needs without special requirements.

[0018] Furthermore, the polymer is selected from one or more of polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, polyethylene oxide, polyvinylidene fluoride, polyvinyl chloride, polyvinyl alcohol, polyacrylic acid, polyethyl acetate, polyethylene glycol divinyl ether, and polycaprolactone; the lithium salt is selected from one or more of lithium hexafluorophosphate, lithium bis(fluorosulfonyl)imide, lithium tetrafluoroborate, lithium perchlorate, lithium bis(oxalatoborate), lithium hexafluoroarsenate, lithium bis(oxalatoborate), lithium trifluoromethanesulfonate, and lithium bis(trifluoromethylsulfonyl)imide; the ion conductive powder is selected from one or more of lithium lanthanum zirconium oxide (LLZO), lithium lanthanum titanium oxide (LLTO), lithium aluminum titanium phosphate (LATP), and lithium aluminum germanium phosphate (LAGP); and the organic solvent is selected from one or more of dimethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, methyl formate, dimethoxymethane, ethylene carbonate, and propylene carbonate. Furthermore, in the composite electrolyte ink, the amount of the photocurable functional agent should not be too much or too little. Too much will be detrimental to the migration of lithium ions, while too little will prevent the electrolyte from being completely cured and formed.

[0019] Furthermore, during the light curing, the wavelength range of the light source used for light curing is 100nm-500nm, and the intensity is 1000mW / cm 2 -4000 mW / cm2 .

[0020] Furthermore, to avoid the need for drying the positive electrode after printing, in S2, a heating pad is placed under the glass substrate to heat the glass substrate to dry the positive electrode on the glass substrate. The heating pad is heated at a temperature of 35°C-200°C. The present invention performs printing and heating and drying simultaneously, which not only does not affect the printing process and printing quality of the positive electrode, but also saves process time, shortens the process flow, and is conducive to industrialization.

[0021] Furthermore, the present invention also includes a solid-state lithium-ion battery, which is prepared by the above method.

[0022] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0023] 1. The method of the present invention can realize the continuous preparation of solid-state batteries by 3D printing integration. On the one hand, it improves the close bonding between the solid electrolyte and the electrode, which is beneficial to improving the solid-solid interface compatibility and promoting lithium ion migration. On the other hand, by combining the advantages of ink direct writing molding and photocuring molding technology, the traditional 3D printing process is improved. There is no need for the subsequent sintering and degreasing process of the traditional photocuring process and the large amount of non-electrochemically active additives in the direct writing process, which simplifies the molding ink formula and printing process, overcomes the application obstacles of 3D printing technology in solid-state lithium-ion batteries, and is beneficial to process scale; in addition, the entire printing preparation process avoids the current collector, drying, pole piece compaction, assembly, thermal plastic sealing and other processes required in the traditional battery preparation process. The whole process adopts 3D printing technology, which greatly simplifies the full battery preparation process and realizes the integrated continuous printing preparation of solid-state lithium-ion batteries. The solid-state lithium-ion battery prepared by the method of the present invention has the advantages of high energy density and good cycle performance;

[0024] 2. The present invention uses 3D printing technology to precisely control the morphology and structure of the electrolyte and electrode, which is conducive to large-scale manufacturing and can improve the ion transfer rate between the electrode and the solid electrolyte; its preparation process is simple, without calcination or heat treatment steps, avoiding time and energy consumption; at the same time, the present invention uses a small amount of photocuring agent to replace the use of binder, avoiding the use of more binders (such as polyvinylidene fluoride, carboxymethyl cellulose, etc.) in traditional electrodes, increasing the content of active substances in the electrode, seamlessly integrating the battery, and eliminating additional solvent drying processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the structure of a solid-state lithium-ion battery prepared by 3D printing of the present invention;

[0026] Figure 2is a cycle curve diagram of the battery of Example 1 at 1.0C;

[0027] Figure 3 This is the first charge and discharge curve of the battery of Example 2 at 0.1C.

[0028] Figure 1 In the figure, 1 is the tab, 2 is the solid electrolyte, 3 is the positive electrode, and 4 is the negative electrode. DETAILED DESCRIPTION

[0029] The present invention will be described in detail below with reference to the accompanying drawings.

[0030] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0031] like Figure 1 As shown, a method for preparing a solid-state lithium-ion battery using 3D printing comprises the following steps:

[0032] S1. Take the positive electrode, negative electrode and composite electrolyte ink and stir them evenly on a magnetic stirrer to obtain positive electrode ink, negative electrode ink and composite electrolyte ink respectively; wherein the positive electrode ink includes 1%-10% of a photocurable functional agent, 75%-90% of a positive electrode active material, 2%-10% of a conductive agent and 1%-8% of a dispersant, and the positive electrode active material is selected from one or more of lithium cobalt oxide, lithium iron phosphate, lithium manganese oxide, nickel cobalt manganese ternary, nickel cobalt aluminum material, and manganese-based lithium-rich material; the conductive agent is selected from one or more of conductive carbon black, conductive graphite, carbon nanotubes, acetylene black, graphene, and carbon fiber; the dispersant is selected from polyacrylic acid, acetonitrile, N-methylpyrrolidone, dimethylacetamide, ethanol, glycerol , ethylene carbonate, propylene carbonate one or more; the negative electrode ink includes 1%-10% of a photocurable functional agent, 75%-90% of a negative electrode active material, 2%-10% of a conductive agent and 1%-8% of a dispersant, the negative electrode active material is selected from one or more of graphite, silicon carbon, lithium titanate; the conductive agent is selected from one or more of conductive carbon black, conductive graphite, carbon nanotubes, acetylene black, graphene, carbon fiber; the dispersant is selected from one or more of polyacrylic acid, acetonitrile, N-methylpyrrolidone, dimethylacetamide, ethanol, glycerol, ethylene carbonate, propylene carbonate; the composite electrolyte ink includes 1%-10% of a photocurable functional agent, 45%-75% of a polymer, 1%- 20% lithium salt, 1%-20% ion conductive powder and 1%-10% organic solvent, the polymer is selected from one or more of polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, polyethylene oxide, polyvinylidene fluoride, polyvinyl chloride, polyvinyl alcohol, polyacrylic acid, polyethyl acetate, polyethylene glycol divinyl ether, polycaprolactone; the lithium salt is selected from one or more of lithium hexafluorophosphate, lithium bis(fluorosulfonyl)imide, lithium tetrafluoroborate, lithium perchlorate, lithium bis(oxalatoborate), lithium hexafluoroarsenate, lithium bis(oxalatoborate), lithium trifluoromethanesulfonate and lithium bis(trifluoromethylsulfonyl)imide; the ion conductive powder is selected from one or more of lithium lanthanum zirconium oxide (LLZO), lithium lanthanum titanium oxide (LLTO), lithium aluminum titanium phosphate (LAA TP), lithium aluminum germanium phosphate (LAGP); the organic solvent is selected from one or more of dimethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, methyl formate, dimethoxymethane, ethylene carbonate, and propylene carbonate; the photocuring functional agent includes a polymer monomer and a photoinitiator, the mass ratio of the polymer monomer to the photoinitiator is 50-150:1, and the polymer monomer is selected from one or more of hydroxyethyl acrylate, trimethylolpropane triacrylate, polyethylene glycol methacrylate, polyethylene glycol diacrylate, methoxypolyethylene glycol methacrylate, cyclohexene oxide, ethoxylated trimethylpropane triacrylate, methacrylate, and hexanediol diacrylate;The photoinitiator is one or more of trimethylbenzoyl-diphenylphosphine oxide, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-hydroxycyclohexyl phenyl ketone, 2,2-dihydroxymethylpropionic acid, and xylene ketone;

[0033] S2, placing the cathode ink in the syringe of a 3D printer, setting the printer parameters, printing layer by layer on a glass substrate and simultaneously performing light curing to obtain a 3D printed cathode;

[0034] S3, placing the composite electrolyte ink in the syringe of a 3D printer, setting the printer parameters, printing layer by layer on the surface of the positive electrode printed in S2 and simultaneously performing light curing to obtain an electrolyte that is tightly bonded to the positive electrode surface;

[0035] S4, placing the negative electrode ink in the syringe of the 3D printer, setting the printer parameters, printing layer by layer on the electrolyte surface printed in S3 and simultaneously performing light curing to obtain a negative electrode that is closely bonded to the electrolyte surface, and then obtaining a positive electrode / electrolyte / negative electrode battery structure;

[0036] S5. Peel the battery structure obtained in S4 off the glass plate, print and package the outer layer, and use photosensitive epoxy resin as the packaging material to obtain the battery structure.

[0037] In order to better illustrate the present invention, specific embodiments are listed below:

[0038] Example 1

[0039] A method for preparing a high-nickel ternary NCM811 solid-state lithium-ion battery by 3D printing, comprising the following steps:

[0040] S1. Take the positive electrode, negative electrode and composite electrolyte ink and stir them evenly on a magnetic stirrer to obtain positive electrode ink, negative electrode ink and composite electrolyte ink respectively; wherein the positive electrode ink includes 5% of a photocurable functional agent, 85% of a high nickel ternary NCM811 material, 5% of a conductive carbon black and 5% of N-methylpyrrolidone; the negative electrode ink includes 7% of a photocurable functional agent, 85% of a graphite material, 5% of acetylene black and 3% of N-methylpyrrolidone; the composite electrolyte ink includes 2% of a photocurable functional agent, 75% of a polyvinylidene fluoride-hexafluoropropylene copolymer, 5% of lithium hexafluorophosphate, 15% of a lithium lanthanum zirconium oxide and 3% of dimethyl carbonate; the photocurable functional agent includes a polymer monomer polyethylene glycol diacrylate and a photoinitiator trimethylbenzoyl-diphenylphosphine oxide, and the mass ratio of the polymer monomer to the photoinitiator is 100:1;

[0041] S2. Place the positive electrode ink in the syringe of the 3D printer, set the printer parameters, print layer by layer on a glass substrate at 100°C at a printing speed of 20 mL / min and perform light curing at the same time. The light source wavelength is 405 nm and the intensity is 4000 mW / cm 2 , obtaining a 3D printed positive electrode;

[0042] S3: Place the composite electrolyte ink in the syringe of the 3D printer, set the printer parameters, and print layer by layer on the positive electrode surface printed in S2 at a printing speed of 20 mL / min and perform light curing at the same time. The light source wavelength is 405 nm and the intensity is 4000 mW / cm 2 , obtaining an electrolyte that is tightly bonded to the cathode surface;

[0043] S4: Place the negative electrode ink in the syringe of the 3D printer, set the printer parameters, and print layer by layer on the electrolyte surface printed in S3 at a printing speed of 20 mL / min while performing light curing. The light source wavelength is 405 nm and the intensity is 4000 mW / cm 2 , obtaining a negative electrode that is tightly bonded to the electrolyte surface, and then obtaining a positive electrode / electrolyte / negative electrode battery structure;

[0044] S5: Peel the battery structure obtained in S4 off the glass plate, and print the outer layer at a printing speed of 30 mL / min. The packaging material is photosensitive epoxy resin, the light source wavelength is 405 nm, and the intensity is 4000 mW / cm 2 , you will get it.

[0045] Example 2

[0046] A method for preparing a high-nickel ternary NCM622 solid-state lithium-ion battery by 3D printing, comprising the following steps:

[0047] S1. Take the positive electrode, negative electrode and composite electrolyte ink and stir them evenly on a magnetic stirrer to obtain positive electrode ink, negative electrode ink and composite electrolyte ink respectively; wherein the positive electrode ink includes 1% of a photocurable functional agent, 90% of a high nickel ternary NCM622 material, 4% of a conductive carbon black and 5% of N-methylpyrrolidone; the negative electrode ink includes 1% of a photocurable functional agent, 90% of a silicon carbon material, 6% of acetylene black and 3% of N-methylpyrrolidone; the composite electrolyte ink includes 2% of a photocurable functional agent, 75% of polyacrylic acid, 5% of lithium bis(fluorosulfonyl)imide, 15% of lithium lanthanum titanium oxide and 3% of ethylene carbonate; the photocurable functional agent includes a polymer monomer ethoxylated trimethylolpropane triacrylate and a photoinitiator 2-hydroxy-2-methyl 1-phenyl 1-propanone, and the mass ratio of the polymer monomer to the photoinitiator is 80:1;

[0048] S2. Place the positive electrode ink in the syringe of the 3D printer, set the printer parameters, print layer by layer on a glass substrate at 120°C at a printing speed of 10 mL / min and perform light curing at the same time. The light source wavelength is 365 nm and the intensity is 4000 mW / cm 2 , obtaining a 3D printed positive electrode;

[0049] S3: Place the composite electrolyte ink in the syringe of the 3D printer, set the printer parameters, and print layer by layer on the positive electrode surface printed in S2 at a printing speed of 10 mL / min and perform light curing at the same time. The light source wavelength is 365 nm and the intensity is 4000 mW / cm 2 , obtaining an electrolyte that is tightly bonded to the cathode surface;

[0050] S4: Place the negative electrode ink in the syringe of the 3D printer, set the printer parameters, and print layer by layer on the electrolyte surface printed in S3 at a printing speed of 10 mL / min and perform light curing at the same time. The light source wavelength is 365 nm and the intensity is 4000 mW / cm 2 , obtaining a negative electrode that is tightly bonded to the electrolyte surface, and then obtaining a positive electrode / electrolyte / negative electrode battery structure;

[0051] S5: Peel the battery structure obtained in S4 off the glass plate, and print the outer layer at a printing speed of 30 mL / min. The packaging material is photosensitive epoxy resin, the light source wavelength is 365 nm, and the intensity is 4000 mW / cm 2 , you will get it.

[0052] Example 3

[0053] A 3D printing method for preparing Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 The method of O2 type solid-state lithium ion battery comprises the following steps:

[0054] S1, take the positive electrode, negative electrode and composite electrolyte ink and stir them evenly on a magnetic stirrer to obtain positive electrode ink, negative electrode ink and composite electrolyte ink respectively; wherein the positive electrode ink includes 4% of light curing functional agent, 80% of Li 1.2 Mn 0.54 Ni 0.13 Co 0.13O2 material, 8% conductive carbon black and 8% ethanol; the negative electrode ink includes 1% photocurable functional agent, 80% lithium titanate material, 10% acetylene black and 9% ethanol; the composite electrolyte ink includes 2% photocurable functional agent, 76% polyethylene oxide, 10% lithium bis(oxalatoborate), 10% lithium lanthanum titanium oxide and 2% ethylene carbonate; the photocurable functional agent includes polymer monomer ethoxylated trimethylolpropane triacrylate and photoinitiator 2-hydroxy-2-methyl 1-phenyl 1-propanone, and the mass ratio of polymer monomer to photoinitiator is 50:1;

[0055] S2. Place the positive electrode ink in the syringe of the 3D printer, set the printer parameters, print layer by layer on a glass substrate at 90°C at a printing speed of 5 mL / min and perform light curing at the same time. The light source wavelength is 365 nm and the intensity is 4000 mW / cm 2 , obtaining a 3D printed positive electrode;

[0056] S3: Place the composite electrolyte ink in the syringe of the 3D printer, set the printer parameters, and print layer by layer on the positive electrode surface printed in S2 at a printing speed of 5 mL / min and perform light curing at the same time. The light source wavelength is 365 nm and the intensity is 4000 mW / cm 2 , obtaining an electrolyte that is tightly bonded to the cathode surface;

[0057] S4: Place the negative electrode ink in the syringe of the 3D printer, set the printer parameters, and print layer by layer on the electrolyte surface printed in S3 at a printing speed of 5 mL / min and perform light curing at the same time. The light source wavelength is 365 nm and the intensity is 4000 mW / cm 2 , obtaining a negative electrode that is tightly bonded to the electrolyte surface, and then obtaining a positive electrode / electrolyte / negative electrode battery structure;

[0058] S5: Peel the battery structure obtained in S4 off the glass plate, and print the outer layer at a printing speed of 20 mL / min. The packaging material is photosensitive epoxy resin, the light source wavelength is 365 nm, and the intensity is 4000 mW / cm 2 , you will get it.

[0059] Comparative Example 1

[0060] Taking the preparation of a high-nickel ternary NCM811 solid-state lithium-ion battery in Example 1 as an example, the existing 3D printing method is used to separately print the positive electrode and the negative electrode, and then assemble them into a lithium-ion battery. The steps are as follows:

[0061] S1. Take the positive electrode, negative electrode and composite electrolyte ink and stir them evenly on a magnetic stirrer to obtain positive electrode ink, negative electrode ink and composite electrolyte ink respectively; wherein the positive electrode ink includes 5% of a photocurable functional agent, 85% of a high nickel ternary NCM811 material, 5% of a conductive carbon black and 5% of N-methylpyrrolidone; the negative electrode ink includes 7% of a photocurable functional agent, 85% of a graphite material, 5% of acetylene black and 3% of N-methylpyrrolidone; the composite electrolyte ink includes 2% of a photocurable functional agent, 75% of a polyvinylidene fluoride-hexafluoropropylene copolymer, 5% of lithium hexafluorophosphate, 15% of a lithium lanthanum zirconium oxide and 3% of dimethyl carbonate; the photocurable functional agent includes a polymer monomer polyethylene glycol diacrylate and a photoinitiator trimethylbenzoyl-diphenylphosphine oxide, and the mass ratio of the polymer monomer to the photoinitiator is 100:1;

[0062] S2. Place the positive electrode ink in the syringe of the 3D printer, set the printer parameters, print layer by layer on a glass substrate at 100°C at a printing speed of 20 mL / min and perform light curing at the same time. The light source wavelength is 405 nm and the intensity is 4000 mW / cm 2 , obtaining a 3D printed positive electrode;

[0063] S3: Place the composite electrolyte ink in the syringe of a 3D printer, set the printer parameters, and print layer by layer on a glass substrate at 100°C at a printing speed of 20 mL / min while performing light curing. The light source wavelength is 405 nm and the intensity is 4000 mW / cm 2 , obtaining a 3D printed electrolyte;

[0064] S4. Place the negative electrode ink in the syringe of the 3D printer, set the printer parameters, print layer by layer on a glass substrate at 100°C at a printing speed of 20 mL / min and perform simultaneous light curing. The light source wavelength is 405 nm and the intensity is 4000 mW / cm 2 , obtaining a 3D printed negative electrode;

[0065] S5: Place the positive and negative electrodes obtained in S2 and S4 on both sides of the electrolyte printed in S3 to form a battery structure. Print the package on the outer layer at a printing speed of 30 mL / min. The packaging material is photosensitive epoxy resin. The light source wavelength is 405 nm and the intensity is 4000 mW / cm 2 , you will get it.

[0066] Comparative Example 2

[0067] Comparative Example 2 is the same as Example 1, except that the amount of the positive light curing functional agent is 25%.

[0068] Comparative Example 3

[0069] Comparative Example 3 is the same as Example 1, except that the amount of the photocuring functional agent in the composite electrolyte is 35%.

[0070] Comparative Example 4

[0071] Comparative Example 4 is the same as Example 1, except that the photocuring functional agent contains polymer epoxy resin and photoinitiator IRGACURE 819.

[0072] Comparative Example 5

[0073] The types of positive electrode active material, negative electrode active material and electrolyte used in Comparative Example 5 are the same as those in Example 1, but the printing process is different.

[0074] A method for printing and preparing a high-nickel ternary NCM811 solid-state lithium-ion battery using ink direct writing technology comprises the following steps:

[0075] S1. Take the positive electrode, negative electrode and composite electrolyte ink and stir them evenly on a magnetic stirrer to obtain positive electrode ink, negative electrode ink and composite electrolyte ink respectively; wherein the positive electrode ink includes 10% PVDF binder, 75% high nickel ternary NCM811 material, 10% graphene and 5% N-methylpyrrolidone; the negative electrode ink includes 10% PVDF binder, 75% graphite material, 10% graphene and 5% N-methylpyrrolidone; the composite electrolyte ink includes 10% PVDF binder, 65% polyvinylidene fluoride-hexafluoropropylene copolymer, 5% lithium hexafluorophosphate, 15% lithium lanthanum zirconium oxide and 5% dimethyl carbonate;

[0076] S2. Place the cathode ink in the syringe of a 3D printer, set the printer parameters, and print layer by layer on a glass substrate at 100°C at a printing speed of 20 mL / min;

[0077] S3, placing the composite electrolyte ink in the syringe of a 3D printer, setting the printer parameters, and printing layer by layer on the positive electrode surface printed in S2 at a printing speed of 20 mL / min to obtain an electrolyte that is tightly bonded to the positive electrode surface;

[0078] S4. Place the negative electrode ink in the syringe of the 3D printer, set the printer parameters, and print layer by layer on the electrolyte surface printed in S3 at a printing speed of 20 mL / min to obtain a negative electrode that is closely bonded to the electrolyte surface, thereby obtaining a positive electrode / electrolyte / negative electrode battery structure;

[0079] S5. Peel the battery structure obtained in S4 off the glass plate and seal it with aluminum foil in a glove box.

[0080] Experimental analysis

[0081] Test method:

[0082] The printed battery was subjected to a charge and discharge test on a Land charge and discharge tester, and the test cutoff voltage was 2.8V-4.5V (1C=200mAh / g).

[0083] Test results

[0084] Example 1: The discharge capacity at 0.1C rate reaches 188.7 mAh / g, and the coulombic efficiency is 88.8%; the capacity retention rate after 50 cycles at 1.0C rate reaches 95.7%. Figure 2 As shown in the figure, the discharge capacity is still 162.6 mAh / g at 5.0 C. It can be seen that the battery prepared by 3D printing has a high discharge capacity, excellent cycle stability and good rate performance.

[0085] Example 2: The discharge capacity at 0.1C rate reaches 178.7 mAh / g, and the coulombic efficiency is 85.6%; the capacity retention rate after 50 cycles at 1.0C rate reaches 96.3%; the discharge capacity at 5.0C rate is still 159.2 mAh / g, as shown in FIG. Figure 3 As shown in Figure 2, it can be seen that the battery prepared by 3D printing has a high discharge capacity, excellent cycle stability and good rate performance.

[0086] Example 3: The discharge capacity reached 258.6 mAh / g at a 0.1C rate, with a coulombic efficiency of 80.3%. After 50 cycles at a 1.0C rate, the capacity retention reached 88.7%. At 5.0C, the discharge capacity remained at 182.2 mAh / g. This demonstrates that the 3D-printed battery exhibits high discharge capacity, excellent cycling stability, and good rate performance.

[0087] Comparative Example 1: Its discharge capacity reached 175.9 mAh / g at a 0.1C rate, with a coulombic efficiency of 83.1%. Its capacity retention reached 87.7% after 50 cycles at a 1.0C rate, and its discharge capacity reached 140.6 mAh / g at 5.0C. This shows that the performance of the battery produced by 3D printing the positive and negative electrodes and electrolyte separately and then assembling them is inferior to that of the battery produced by 3D printing in an integrated and continuous manner.

[0088] Comparative Example 2: Its discharge capacity reached 170.1 mAh / g at a 0.1C rate, with a coulombic efficiency of 80.8%. Its capacity retention reached 80.9% after 50 cycles at a 1.0C rate, and its discharge capacity remained at 152.9 mAh / g at 5.0C. This indicates that excessive addition of a photocurable functional agent to the positive electrode is detrimental to the battery's electrochemical performance.

[0089] Comparative Example 3: At a 0.1C rate, the discharge capacity reached 180.1 mAh / g, with a coulombic efficiency of 87.8%. At a 1.0C rate, the capacity retention reached 89.3% after 50 cycles. However, at a 5.0C rate, the discharge capacity was only 141.3 mAh / g. This indicates that excessive addition of a photocurable functional agent to the composite electrolyte is detrimental to the battery's electrochemical performance.

[0090] Comparative Example 4: Its discharge capacity at a 0.1C rate was only 141.5 mAh / g, with a Coulombic efficiency of 75.6%. Its capacity retention after 50 cycles at a 1.0C rate was only 65.2%. At a 5.0C rate, the discharge capacity was only 91.3 mAh / g. The choice of visible light curing agent is crucial to the electrochemical performance of the battery.

[0091] Comparative Example 5: Its discharge capacity at a 0.1C rate was only 135.1 mAh / g, with a coulombic efficiency of 72.2%. Its capacity retention after 50 cycles at a 1.0C rate was only 56.7%, and its discharge capacity at 5.0C was only 68.9 mAh / g. The direct ink printing process requires a relatively large amount of binder to facilitate the formation of the printed part, resulting in a relatively low amount of active material in the electrode. Furthermore, this technology is not suitable for electrolyte printing due to the excessive additives, which hinder lithium ion migration. Direct ink printing is not suitable for the integrated continuous printing of solid-state batteries.

[0092] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a solid-state lithium-ion battery using 3D printing, characterized in that: The following steps are involved: S1. Take the positive electrode, negative electrode and composite electrolyte ink and stir them evenly on a magnetic stirrer to obtain positive electrode ink, negative electrode ink and composite electrolyte ink respectively; S2, placing the cathode ink in the syringe of a 3D printer, setting the printer parameters, printing layer by layer on a glass substrate and simultaneously performing light curing to obtain a 3D printed cathode; S3, placing the composite electrolyte ink in the syringe of a 3D printer, setting the printer parameters, printing layer by layer on the surface of the positive electrode printed in S2 and simultaneously performing light curing to obtain an electrolyte that is tightly bonded to the positive electrode surface; S4, placing the negative electrode ink in the syringe of the 3D printer, setting the printer parameters, printing layer by layer on the electrolyte surface printed in S3 and simultaneously performing light curing to obtain a negative electrode that is closely bonded to the electrolyte surface, and then obtaining a positive electrode / electrolyte / negative electrode battery structure; S5. Peel the battery structure obtained in S4 from the glass plate, and print the outer layer packaging, wherein the packaging material is a photosensitive epoxy resin; The positive electrode ink comprises, by mass percentage, 1%-10% of a photocurable functional agent, 75%-90% of a positive electrode active material, 2%-10% of a conductive agent, and 1%-8% of a dispersant; The negative electrode ink comprises, by mass percentage, 1%-10% of a photocurable functional agent, 75%-90% of a negative electrode active material, 2%-10% of a conductive agent, and 1%-8% of a dispersant; Calculated by mass percentage, the composite electrolyte ink comprises 1%-10% of a photocurable functional agent, 45%-75% of a polymer, 1%-20% of a lithium salt, 1%-20% of an ion conductive powder, and 1%-10% of an organic solvent; The photocuring functional agent includes a polymer monomer and a photoinitiator, the mass ratio of the polymer monomer to the photoinitiator is 50-150:1, the polymer monomer is selected from one or more of hydroxyethyl acrylate, trimethylolpropane triacrylate, polyethylene glycol methacrylate, polyethylene glycol diacrylate, methoxypolyethylene glycol methacrylate, cyclohexene oxide, ethoxylated trimethylpropane triacrylate, methacrylate, and hexanediol diacrylate; the photoinitiator is one or more of trimethylbenzoyl-diphenylphosphine oxide, 2-hydroxy-2-methyl 1-phenyl 1-propanone, 1-hydroxycyclohexyl phenyl ketone, 2,2-dihydroxymethylpropionic acid, and xylene ketone.

2. The method for preparing a solid-state lithium-ion battery using 3D printing according to claim 1, wherein: The positive electrode active material is selected from one or more of lithium cobalt oxide, lithium iron phosphate, lithium manganese oxide, nickel cobalt manganese ternary, nickel cobalt aluminum material, and manganese-based lithium-rich material; the conductive agent is selected from one or more of conductive carbon black, conductive graphite, carbon nanotubes, acetylene black, graphene, and carbon fiber; the dispersant is selected from one or more of polyacrylic acid, acetonitrile, N-methylpyrrolidone, dimethylacetamide, ethanol, glycerol, ethylene carbonate, and propylene carbonate.

3. The method for preparing a solid-state lithium-ion battery using 3D printing according to claim 1, wherein: The negative electrode active material is selected from one or more of graphite, silicon carbon, and lithium titanate; the conductive agent is selected from one or more of conductive carbon black, conductive graphite, carbon nanotubes, acetylene black, graphene, and carbon fiber; and the dispersant is selected from one or more of polyacrylic acid, acetonitrile, N-methylpyrrolidone, dimethylacetamide, ethanol, glycerol, ethylene carbonate, and propylene carbonate.

4. The method for preparing a solid-state lithium-ion battery using 3D printing according to claim 1, wherein: The polymer in the composite electrolyte ink is selected from one or more of polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, polyethylene oxide, polyvinylidene fluoride, polyvinyl chloride, polyvinyl alcohol, polyethyl acetate, polyethylene glycol divinyl ether, and polycaprolactone; the lithium salt is selected from one or more of lithium hexafluorophosphate, lithium bis(fluorosulfonyl)imide, lithium tetrafluoroborate, lithium perchlorate, lithium bis(oxalatoborate), lithium hexafluoroarsenate, lithium bis(oxalatoborate), lithium trifluoromethanesulfonate, and lithium bis(trifluoromethylsulfonyl)imide; the ion conductive powder is selected from one or more of lithium lanthanum zirconium oxide, lithium lanthanum titanium oxide, lithium aluminum titanium phosphate, and lithium aluminum germanium phosphate; the organic solvent is selected from one or more of dimethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, methyl formate, dimethoxymethane, ethylene carbonate, and propylene carbonate.

5. The method for preparing a solid-state lithium-ion battery using 3D printing according to any one of claims 1 to 4, characterized in that: During light curing, the wavelength range of the light source used for light curing is 100nm-500nm, and the intensity is 1000mW / cm 2 -4000mW / cm 2 .

6. The method for preparing a solid-state lithium-ion battery using 3D printing according to claim 5, wherein: In S2, a heating pad is placed under the glass substrate to heat the glass substrate so as to dry the positive electrode on the glass substrate. The heating temperature of the heating pad is 35°C-200°C.

7. A solid-state lithium-ion battery, characterized in that: The solid-state lithium-ion battery is prepared by the method according to any one of claims 1 to 6.

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