All-solid-state battery based on 3D printing technology and preparation method

Abstract

The invention relates to the technical field of battery design and manufacturing processes, in particular to an all-solid-state battery based on a 3D printing technology and a preparation method, and the all-solid-state battery comprises a positive electrode, a negative electrode, a solid electrolyte and a current collector; a positive electrode is composed of lithium cobalt nickel manganese oxide and the like, and a novel conductive agent and a multifunctional modifier are added; the negative electrode is made of a silicon-tin-carbon composite material and the like; the solid electrolyte contains components such as lithium, lanthanum, zirconium, tantalum and oxygen; the current collector is alloy foil and is plated with a specific film, and the material proportion and characteristics of all parts are clear. The unique material formula improves the battery performance, and enhances the energy density and cycle stability; the structure is accurately controlled through the 3D printing technology, and the production efficiency and the battery consistency are improved; the solid electrolyte guarantees safety, reduces hidden dangers, and is beneficial to wide application in multiple fields.

Description

Technical Field

[0001] The present invention relates to the technical field of battery design and manufacturing processes, and particularly to an all-solid-state battery based on 3D printing technology and a preparation method thereof. Background Art

[0002] In the current era of rapid technological development, battery technology, as a key support in many fields, the improvement of its performance has always been a research hotspot in the scientific research and industrial circles. All-solid-state batteries are regarded as an important direction for future battery development due to their advantages such as high energy density and high safety, and have broad application prospects in fields such as electric vehicles, portable electronic devices, and energy storage systems. However, the current development of all-solid-state batteries still faces many challenges, seriously restricting their large-scale commercial applications.

[0003] From the perspective of electrode materials, the specific capacity and cycle stability of traditional cathode materials are difficult to meet the growing demands. For example, common lithium cobalt oxides have a relatively high voltage platform, but cobalt resources are scarce, the cost is high, and structural instability is prone to occur during the cycling process. Lithium nickel cobalt manganese ternary materials have certain advantages in terms of energy density, but in a high-temperature environment, their thermal stability is poor, which will lead to a decline in battery performance and even pose safety hazards. At the same time, the interfacial compatibility between the cathode material and the solid electrolyte is not good, and a large interfacial resistance is easily formed during charge and discharge, affecting the ion transport efficiency and reducing the charge and discharge performance of the battery.

[0004] Anode materials also have problems. The theoretical specific capacity of traditional graphite anodes is relatively low and cannot meet the requirements of high-energy-density batteries. Although silicon-based anode materials have a high specific capacity, they will undergo huge volume changes during charge and discharge, resulting in material pulverization and shedding, thereby greatly shortening the cycle life of the battery. In addition, the interface between the anode material and the solid electrolyte is also unstable, easily triggering the growth of lithium dendrites, piercing the solid electrolyte, causing battery short circuits, and seriously threatening the safety of the battery.

[0005] The research and development of solid electrolytes is also one of the key problems faced by all-solid-state batteries. At present, the ionic conductivity of solid electrolytes is generally lower than that of liquid electrolytes, resulting in limited charge and discharge performance of the battery. Moreover, the preparation process of solid electrolytes is complex and the cost is high, making it difficult to achieve large-scale production. At the same time, the poor interfacial contact between the solid electrolyte and the electrode material further increases the internal resistance of the battery and affects the overall performance of the battery.

[0006] In terms of battery preparation processes, the existing preparation methods are difficult to precisely control the microstructure and composition distribution of electrode materials and solid electrolytes. Traditional processes such as coating and pressing cannot meet the strict requirements of all-solid-state batteries for material uniformity and interfacial quality, resulting in poor consistency of battery performance and making it difficult to achieve industrial large-scale production.

[0007] With the continuous improvement of the battery performance requirements in various industries, it is urgent to develop a high-performance, low-cost, and large-scale production all-solid-state battery technology. The all-solid-state battery and its preparation method based on 3D printing technology proposed in this patent precisely aim at the above problems, aiming to break through the bottleneck of the existing technology, promote the development of all-solid-state battery technology, and meet the urgent market demand for high-performance batteries. Summary of the Invention

[0008] (I) Technical Problems to be Solved In view of the deficiencies of the existing technology, the present invention provides an all-solid-state battery and its preparation method based on 3D printing technology.

[0009] (II) Technical Solutions An all-solid-state battery based on 3D printing technology includes: a positive electrode material composed of lithium cobalt nickel manganese oxide , a novel composite conductive agent, nano-scale lithium iron phosphate, and a multifunctional modifier; the multifunctional modifier is a compound of γ-aminopropyltrimethoxysilane and diethylenetriamine pentamethylene phosphonic acid; the molecular formula of γ-aminopropyltrimethoxysilane is C 6 H 17 NO 3 Si, and its structural formula is: ; The molecular formula of the diethylenetriamine pentamethylene phosphonic acid is C 9 H 28 N 3 O 15 P 5 , and its structural formula is: ; The multifunctional modifier reacts with lithium cobalt nickel manganese oxide as follows to improve the interfacial performance: ; A negative electrode material includes a silicon-tin-carbon composite negative electrode material, flake graphite, a novel binder polyacrylonitrile-polyvinylidene fluoride copolymer, and a composite conductive agent; the structural formula of the polyacrylonitrile-polyvinylidene fluoride copolymer is: ; A solid electrolyte is composed of lithium lanthanum zirconium tantalum oxide, sulfur and nitrogen co-doped carbon nanofibers SN-CNF, nano-titanium dioxide, and a plasticizer; Current collectors: A copper-titanium alloy foil with a thickness of 10 - 30 μm is used as the negative electrode current collector, and an aluminum-magnesium alloy foil with a thickness of 8 - 20 μm is used as the positive electrode current collector. Moreover, a lithium aluminum titanium phosphate oxygen LATP film with a thickness of 50 - 200 nm is coated on the surface of the current collector by atomic layer deposition, and the reaction formula is: .

[0010] Preferably, the lithium cobalt nickel manganese oxide is subjected to segmented high-temperature annealing treatment, first annealed at 400-500 °C for 2-3 hours, and then annealed at 700-900 °C for 5-10 hours to precisely control its crystal structure, and the error of the atomic ratio of cobalt, nickel, and manganese is controlled within ±2%.

[0011] Preferably, the graphene quantum dots in the novel composite conductive agent are subjected to surface amination treatment to enhance their interaction with PEDOT-PSS and CNT, and improve the dispersibility and conductivity of the conductive agent.

[0012] Preferably, during the mechanical alloying process of the silicon-tin-carbon composite anode material, the ball-to-material ratio is 10:1-20:1, the ball milling speed is 400-600 r / min, and the ball milling time is 10-20 hours to ensure sufficient alloying.

[0013] Preferably, in the novel binder polyacrylonitrile-polyvinylidene fluoride copolymer, the mass ratio of PAN to PVDF is 1:3-1:4, which has good flexibility and adhesiveness, and can effectively buffer the volume change during the charge and discharge process of the anode material.

[0014] Preferably, in the composite conductive agent, the mass ratio of Ketjen black to nano copper wire is 0.8:1-2:1, the diameter of the nano copper wire is 10-30 nm, and the length is 5-20 μm to construct an efficient conductive network.

[0015] Preferably, the tantalum doping ratio of lithium lanthanum zirconium tantalum oxide in the solid electrolyte is 1-3% to improve its ionic conductivity and chemical stability.

[0016] Preferably, a preparation method of an all-solid-state battery based on 3D printing technology includes the following steps: Preparation of electrode materials: Mix the components of the positive electrode material in proportion, add an appropriate amount of a mixed solvent of N-methylpyrrolidone NMP and ethylene glycol dimethyl ether DME, and disperse it at a speed of 3000-5000 r / min in a high-shear disperser for 3-6 hours to make a positive electrode paste; mix the components of the negative electrode material in proportion, add the same mixed solvent, and grind it at a speed of 2000-4000 r / min in a horizontal sand mill for 4-8 hours to make a negative electrode paste; 3D printing and forming: Using digital light processing 3D printing technology, print the positive electrode paste and the negative electrode paste on the corresponding current collectors respectively, the printing temperature is 50-80 °C, the exposure time for each layer is 1-3 seconds, and the layer thickness is 30-80 μm; Solid electrolyte coating: Mix the components of the solid electrolyte, add an appropriate amount of a mixed solvent of ethyl methyl carbonate and propyl propionate, ultrasonically disperse it in an ultrasonic homogenizer at a power of 400 - 700 W for 50 - 100 minutes, and then coat it on the printed electrode material by slit coating to form a solid electrolyte layer. The coating speed is 5 - 15 mm / s, and the coating thickness is 50 - 200 μm; Battery assembly and activation: Assemble the positive and negative electrode materials coated with the solid electrolyte layer, encapsulate them in a glove box under argon protection, and then perform multi-stage charge and discharge activation treatment. First, charge at a current of 0.05C to 3.2V, then charge at a current of 0.1C to 4.3V, then discharge at a current of 0.1C to 3.2V, and then discharge at a current of 0.2C to 2.2V. The charge and discharge cycle is 3 - 5 times.

[0017] Preferably, during the preparation of the electrode paste, the stirring ambient temperature is controlled at 22 - 28°C, and the humidity is controlled at 15 - 25%RH to ensure the stability and uniformity of the paste.

[0018] Preferably, during the solid electrolyte coating process, the gap of the slit coating is 0.1 - 0.3 mm to precisely control the coating thickness and uniformity.

[0019] Preferably, the 3D printing technology can also adopt the SEL technology. This technology extrudes battery paste with shear-thinning properties from the printing nozzle and stacks the paste layer by layer to construct a three-dimensional structure designed digitally in advance; and the SEL technology achieves high printing resolution with a minimum feature size as low as 1 μm by using a micro-capillary nozzle.

[0020] Preferably, SEL can provide multi-material manufacturing capabilities with high spatial and compositional precision by switching multiple printing nozzles filled with different component pastes.

[0021] Preferably, the forming methods of the materials printed by the SEL device include photocuring, thermal curing, adhesive solidification, and air-drying solidification.

[0022] (III) Beneficial technical effects Compared with the existing technologies, the beneficial effects of the present invention are: 1. Through unique material formulation design, the comprehensive performance of the battery has been significantly improved; the addition of a novel composite conductive agent in the cathode material enhances the electron conduction ability, and the multifunctional modifier improves the interfacial properties of the material, increasing the specific capacity and cycle stability of the cathode material; the anode material uses a silicon-tin-carbon composite anode material, combined with a novel binder and composite conductive agent, effectively alleviating the volume expansion problem of silicon-based materials and improving the energy density and cycle life of the battery; the addition of sulfur and nitrogen co-doped carbon nanofibers and nano-titanium dioxide in the solid electrolyte significantly increases the ionic conductivity and enhances the charge and discharge performance of the battery.

[0023] 2. The use of solid electrolytes avoids safety hazards such as leakage and combustion caused by liquid electrolytes; at the same time, by optimizing the interface between the electrode material and the solid electrolyte, the growth of lithium dendrites is effectively inhibited, improving the safety of the battery, reducing the risk of battery short circuit, and making it have a broader application prospect in fields with high safety requirements such as electric vehicles and energy storage.

[0024] 3. The application of 3D printing technology makes the preparation of the battery more precise and flexible; it can accurately control the microstructure and composition distribution of the electrode material and the solid electrolyte, realize personalized customized production, improve the consistency of battery performance, and lay a foundation for large-scale industrial production; compared with traditional preparation processes, 3D printing technology can also reduce production processes, lower production costs, and improve production efficiency.

[0025] 4. The present invention reasonably selects and matches materials, reducing the dependence on scarce resources; the environmentally friendly solvents and processes used in the preparation process reduce environmental pollution and meet the requirements of sustainable development; in practical applications, high-performance batteries can improve the usage efficiency of equipment, reduce energy consumption, and further promote green development. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a flowchart for the preparation of an all-solid-state battery based on 3D printing technology proposed by the present invention; Figure 2 is a bar comparison chart of the initial discharge specific capacity of the examples and the comparative examples; Figure 3 is a line comparison chart of the charge and discharge efficiency and internal resistance of the examples and the comparative examples; Figure 4 is a radar comparison chart made after unifying the dimensions of the performance data of the examples and the comparative examples. DETAILED DESCRIPTION OF THE INVENTION

[0027] Example 1

[0028] Preparation of cathode material: Accurately weigh lithium cobalt nickel manganese oxide ( ), 60 g of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid (PEDOT-PSS), 4 g of carbon nanotubes (CNT), 2 g of graphene quantum dots (GQD), 4 g of γ-aminopropyltrimethoxysilane (APTMS), 2 g of diethylenetriamine pentamethylenephosphonic acid (DTPMPA), and 10 g of nanoscale lithium iron phosphate ( ); These materials were added to a mixed solvent containing 100 mL of N-methylpyrrolidone (NMP) and 50 mL of ethylene glycol dimethyl ether (DME), and then poured into a high-shear disperser; They were dispersed at a rotation speed of 3500 r / min for 4 hours to obtain a uniform positive electrode paste; Preparation of negative electrode material: Weigh 40 g of silicon-tin-carbon composite negative electrode material (mass ratio of silicon, tin, and carbon is 4:1:5), 20 g of flake graphite, 15 g of polyacrylonitrile-polyvinylidene fluoride (PAN-PVDF) copolymer (mass ratio of PAN to PVDF is 1:3.5), 8 g of Ketjen black, and 7 g of nanometer copper wire; Add 120 mL of a mixed solvent of NMP and DME (volume ratio 2.5:1), put it into a horizontal sand mill, and grind it at a rotation speed of 2500 r / min for 6 hours to obtain a negative electrode paste; Preparation of solid electrolyte: Measure 30 g of lithium lanthanum zirconium tantalum oxide (LLZTO), 15 g of sulfur and nitrogen co-doped carbon nanofibers (SN-CNF), 15 g of nanometer titanium dioxide ( ), and 10 g of γ-butyrolactone (GBL); Add them to 80 mL of a mixed solvent of ethylene carbonate and propyl propionate (volume ratio 1.5:1), and ultrasonically disperse them in an ultrasonic homogenizer at a power of 500 W for 70 minutes to prepare a solid electrolyte solution; Treatment of current collector: Select a copper-titanium alloy foil with a thickness of 20 μm as the negative electrode current collector and an aluminum-magnesium alloy foil with a thickness of 8 μm as the positive electrode current collector; Use atomic layer deposition (ALD) to coat a lithium aluminum titanium phosphate oxygen (LATP) film on the surface of the current collector, and control the coating thickness at 120 nm; 3D printing and battery assembly: Adopt digital light processing (DLP) 3D printing technology to print the positive electrode paste on the positive electrode current collector; Set the printing temperature at 65 °C, the exposure time for each layer at 2 s, and the layer thickness at 50 μm; Print the negative electrode paste on the negative electrode current collector in the same way; After printing, coat the solid electrolyte solution on the electrode material by slit coating, with a coating speed of 10 mm / s and a coating thickness of 120 μm; Perform battery assembly and encapsulation in a glove box under argon protection; Battery activation: Perform multi-stage charge and discharge activation treatment on the encapsulated battery; First, charge it to 3.2 V at a current of 0.05 C, then charge it to 4.3 V at a current of 0.1 C, then discharge it to 3.2 V at a current of 0.1 C, and finally discharge it to 2.2 V at a current of 0.2 C to complete 1 cycle, and perform a total of 4 cycles; Performance test: The performance test results of the battery prepared in Example 1 show that the initial discharge specific capacity is 180 mAh / g, the capacity retention rate is 85% after 500 cycles, the charge-discharge efficiency reaches 95%, and the internal resistance is 50 mΩ.

[0029] Example 2

[0030] Preparation of the positive electrode material: Change the proportion of each component of the positive electrode material, weigh 55 g of lithium cobalt nickel manganese oxide ( ), 10 g of PEDOT-PSS, 3 g of CNT, 1.5 g of GQD, 3.5 g of APTMS, 1.5 g of DTPMPA, and 15 g of nanoscale lithium iron phosphate ( ); The solvent and preparation process are the same as those in Example 1 to obtain the positive electrode slurry; Preparation of the negative electrode material: Adjust the proportion of the negative electrode material, weigh 35 g of silicon-tin-carbon composite negative electrode material (the mass ratio of silicon, tin, and carbon is 3.5:1:5.5), 22 g of flake graphite, 13 g of polyacrylonitrile-polyvinylidene fluoride (PAN-PVDF) copolymer (the mass ratio of PAN to PVDF is 1:3.2), 7 g of Ketjen black, and 8 g of nanometer copper wire; The subsequent preparation process is the same as that in Example 1 to obtain the negative electrode slurry; Preparation of the solid electrolyte: Change the proportion of the solid electrolyte components, measure 25 g of lithium lanthanum zirconium tantalum oxide (LLZTO), 12 g of sulfur and nitrogen co-doped carbon nanofibers (SN-CNF), 13 g of nanometer titanium dioxide ( ), and 10 g of gamma-butyrolactone (GBL); The solvent and treatment method are the same as those in Example 1 to make the solid electrolyte solution; Current collector treatment, 3D printing, battery assembly and activation: Use the same current collector treatment method, 3D printing technology, battery assembly and activation process as in Example 1; Performance test: The performance test results of the battery prepared in Example 2 show that the initial discharge specific capacity is 175 mAh / g, the capacity retention rate is 83% after 500 cycles, the charge-discharge efficiency is 94%, and the internal resistance is 55 mΩ.

[0031] Example 3

[0032] Preparation of the positive electrode material: Weigh 65 g of lithium cobalt nickel manganese oxide ( ), 14 g of PEDOT-PSS, 4.5 g of CNT, 2.5 g of GQD, 4.5 g of APTMS, 2.5 g of DTPMPA, and 8 g of nanoscale lithium iron phosphate ( ); Prepare the positive electrode slurry according to the method in Example 1; Preparation of the negative electrode material: Weigh 45 g of the silicon-tin-carbon composite negative electrode material (mass ratio of silicon, tin, and carbon is 4.5:1:4.5), 18 g of flake graphite, 17 g of polyacrylonitrile-polyvinylidene fluoride (PAN-PVDF) copolymer (mass ratio of PAN to PVDF is 1:3.8), 9 g of Ketjen black, and 7 g of nano copper wire; the process of preparing the negative electrode slurry is the same as that in Example 1; Preparation of the solid electrolyte: Measure 35 g of lithium lanthanum zirconium tantalum oxide (LLZTO), 18 g of sulfur and nitrogen co-doped carbon nanofibers (SN-CNF), 12 g of nano titanium dioxide ( ), and 10 g of gamma-butyrolactone (GBL); the operation of preparing the solid electrolyte solution is the same as that in Example 1; Current collector treatment, 3D printing, battery assembly, and activation: The same as the current collector treatment, 3D printing, battery assembly, and activation steps in Example 1; Performance test: The battery prepared in Example 3 exhibits excellent comprehensive performance. Its initial discharge specific capacity reaches 185 mAh / g, and it still maintains 87% of its capacity after 500 cycles, showing excellent cycle stability. The charge-discharge efficiency of this battery is as high as 96%, and the internal resistance is only 45 mΩ. These data indicate that this battery has a higher energy density, better cycle life, and better conductivity.

[0033] Comparative example Preparation of the positive electrode material: Use traditional positive electrode materials, only weigh 80 g of lithium cobalt nickel manganese oxide and 20 g of nano lithium iron phosphate ( ); add NMP solvent to make a slurry, without adding a new composite conductive agent and a multifunctional modifier; Preparation of the negative electrode material: Use traditional graphite negative electrode materials, weigh 80 g of graphite, 15 g of polyvinylidene fluoride (PVDF), and 5 g of acetylene black; add NMP to make a negative electrode slurry, without using the silicon-tin-carbon composite negative electrode material, a new binder, and a composite conductive agent; Preparation of the solid electrolyte: Use ordinary solid electrolytes, weigh 60 g of lithium lanthanum zirconium oxide (LLZO), 20 g of nano alumina ( ), and 20 g of propylene carbonate (PC); make a solid electrolyte solution, without adding sulfur and nitrogen co-doped carbon nanofibers and gamma-butyrolactone; Current collector treatment, battery assembly, and activation: Use ordinary copper foil and aluminum foil as current collectors, without special film treatment; battery assembly and activation adopt conventional methods.

[0034] Performance test: The performance test results of the comparative example battery show that its initial discharge specific capacity is only 130 mAh / g, and the capacity retention rate drops significantly to 60% after 500 cycles. The charge-discharge efficiency is 85%, and the internal resistance is as high as 100 mΩ. Compared with Examples 1-3, this comparative example battery performs poorly in all key performance indicators.

[0035] Comparison Table of the Initial Discharge Specific Capacity of the Battery and the Capacity Retention Rate after 500 Cycles: Item Example 1 Example 2 Example 3 Comparative Example Initial discharge specific capacity (mAh / g) 180 175 185 130 Capacity retention rate after 500 cycles (%) 85 83 87 60 Conclusion: This table visually presents the differences in the initial discharge specific capacity and cycle stability of the batteries of each example and comparative example. The initial discharge specific capacity of the examples is higher than that of the comparative examples, and the capacity retention rate after 500 cycles is also significantly better than that of the comparative examples, indicating that the batteries of the present invention perform better in terms of energy output and cycle life.

[0036] Comparison Table of the Charge-Discharge Efficiency and Internal Resistance of the Battery: Item Example 1 Example 2 Example 3 Comparative Example Charge-discharge efficiency (%) 95 94 96 85 Internal resistance (mΩ) 50 55 45 100 Conclusion: This table compares the charge-discharge efficiency and internal resistance of each battery. The charge-discharge efficiency of the examples is significantly higher than that of the comparative examples, and the internal resistance is much lower than that of the comparative examples, indicating that the batteries of the present invention have less energy loss during the charge-discharge process, better electrical conductivity of the battery, and can perform electrical energy conversion more efficiently.

[0037] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An all-solid-state battery based on 3D printing technology, characterized in that: Including: Positive electrode material: lithium cobalt nickel manganese oxide , a new composite conductive agent, nano-scale lithium iron phosphate, and a multifunctional modifier, wherein the multifunctional modifier is a compound of γ-aminopropyltrimethoxysilane and diethylenetriaminepenta(methylenephosphonic acid); the molecular formula of the γ-aminopropyltrimethoxysilane is C6H 17 NO3Si, its structural formula is: ； The molecular formula of the diethylenetriamine penta (methylenephosphonic acid) is C9H 28 N3O 15 P5, whose structural formula is: ； The multifunctional modifier reacts with lithium cobalt nickel manganese oxygen as follows to improve the interface properties: ； Negative electrode material: including silicon-tin-carbon composite negative electrode material, flake graphite, new binder polyacrylonitrile-polyvinylidene fluoride copolymer, composite conductive agent; the structural formula of the polyacrylonitrile-polyvinylidene fluoride copolymer is: ； Solid electrolyte: composed of lithium lanthanum zirconium tantalum oxide, sulfur and nitrogen co-doped carbon nanofiber SN-CNF, nano titanium dioxide, and plasticizer; Current collector: A copper-titanium alloy foil with a thickness of 10-30 μm is used as the negative electrode current collector, and an aluminum-magnesium alloy foil with a thickness of 8-20 μm is used as the positive electrode current collector. A layer of lithium aluminum titanium phosphate oxygen LATP film with a thickness of 50-200 nm is plated on the surface of the current collector by atomic layer deposition. The reaction formula is: 。 2. The all-solid-state battery based on 3D printing technology according to claim 1, characterized in that: The lithium cobalt nickel manganese oxygen undergoes a staged high-temperature annealing treatment, first annealing at 400-500°C for 2-3 hours and then annealing at 700-900°C for 5-10 hours, so as to accurately control its crystal structure, and the error of the cobalt, nickel and manganese atomic ratio is controlled within ±2%.

3. The all-solid-state battery based on 3D printing technology according to claim 1, characterized in that: The graphene quantum dots in the novel composite conductive agent are subjected to surface amination treatment to enhance the interaction between the graphene quantum dots and PEDOT-PSS and CNT, thereby improving the dispersibility and conductivity of the conductive agent.

4. The all-solid-state battery based on 3D printing technology according to claim 1, characterized in that: During the mechanical alloying process of the silicon-tin-carbon composite negative electrode material, the ball-to-material ratio is 10:1-20:1, the ball milling speed is 400-600 r / min, and the ball milling time is 10-20 hours to ensure sufficient alloying.

5. The all-solid-state battery based on 3D printing technology according to claim 1, characterized in that: The mass ratio of PAN to PVDF in the novel binder polyacrylonitrile-polyvinylidene fluoride copolymer is 1:3-1:4, the novel binder has good flexibility and adhesion, and can effectively buffer the volume change of the negative electrode material during the charge and discharge process.

6. The all-solid-state battery based on 3D printing technology according to claim 1, characterized in that: The mass ratio of Ketjen black to nano copper wire in the composite conductive agent is 0.8:1-2:1, the diameter of the nano copper wire is 10-30nm, and the length is 5-20μm, so as to construct an efficient conductive network.

7. The all-solid-state battery based on 3D printing technology according to claim 1, characterized in that: The tantalum doping ratio of lithium lanthanum zirconium tantalum oxide in the solid electrolyte is 1-3% to improve its ionic conductivity and chemical stability.

8. A method for preparing an all-solid-state battery based on 3D printing technology, used to prepare the all-solid-state battery based on 3D printing technology according to any one of claims 1 to 7, characterized in that: The following steps are involved: Preparation of electrode materials: Mix the components of the positive electrode material in proportion, add an appropriate amount of a mixed solvent of N-methylpyrrolidone NMP and ethylene glycol dimethyl ether DME, and disperse them in a high shear disperser at a speed of 3000-5000r / min for 3-6 hours to prepare a positive electrode slurry; mix the components of the negative electrode material in proportion, add the same mixed solvent, and grind them in a horizontal sand mill at a speed of 2000-4000r / min for 4-8 hours to prepare a negative electrode slurry; 3D printing: Using digital light processing 3D printing technology, the positive electrode slurry and the negative electrode slurry are printed on the corresponding current collectors respectively. The printing temperature is 50-80°C, the exposure time of each layer is 1-3 seconds, and the layer thickness is 30-80μm; Solid electrolyte coating: Mix the components of the solid electrolyte, add an appropriate amount of a mixed solvent of ethyl methyl carbonate and propyl propionate, and ultrasonically disperse them in an ultrasonic homogenizer at a power of 400-700W for 50-100 minutes, and then coat them on the printed electrode material by slit coating to form a solid electrolyte layer. The coating speed is 5-15mm / s and the coating thickness is 50-200μm. Battery assembly and activation: Assemble the positive and negative electrode materials coated with the solid electrolyte layer, package them in an argon-protected glove box, and then perform a multi-stage charge and discharge activation treatment. First, charge to 3.2V with a current of 0.05C, then charge to 4.3V with a current of 0.1C, then discharge to 3.2V with a current of 0.1C, and then discharge to 2.2V with a current of 0.2C. The charge and discharge cycle is repeated 3-5 times.

9. The method for preparing an all-solid-state battery based on 3D printing technology according to claim 8, characterized in that: During the preparation of the electrode slurry, the stirring environment temperature is controlled at 22-28°C and the humidity is controlled at 15-25%RH to ensure the stability and uniformity of the slurry.

10. The method for preparing an all-solid-state battery based on 3D printing technology according to claim 8, characterized in that: During the solid electrolyte coating process, the gap of slit coating is 0.1-0.3mm to accurately control the coating thickness and uniformity.

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