A biomimetic three-dimensional electrode and a preparation method and application thereof

Abstract

The application relates to a bionic three-dimensional electrode and a preparation method and application thereof, and belongs to the technical field of batteries. The bionic three-dimensional electrode comprises an electrode main body and a supporting part. The supporting part is connected with the electrode main body and is symmetrically arranged on both sides of the electrode main body. The number of the supporting parts is at least two, and the supporting parts are parallel to each other. The 3D printing centipede structure bionic three-dimensional electrode provided by the application has simple preparation process, and the battery performance can be improved only by improving the three-dimensional electrode structure, which is beneficial to subsequent commercial production.

Description

Technical Field

[0001] This invention relates to the field of battery technology, specifically to a biomimetic three-dimensional electrode, its preparation method, and its application. Background Technology

[0002] With the continuous development of modern industry, human demand for energy is increasing. Therefore, various alkali metal batteries, due to their advantages such as high energy density, high output voltage, safety, and environmental friendliness, have become a research focus for scholars. Currently, alkali metal ion batteries based on flat plate electrodes prepared by coating or spraying methods face a series of problems, including limited power density and poor mechanical structural stability.

[0003] 3D printing, also known as additive manufacturing, involves depositing active materials layer by layer onto a substrate. This allows for the efficient and controllable fabrication of objects of specific thickness and shape without the need for templates, making it widely applicable. 3D printing technology can easily alter the structure of electrodes, creating novel electrodes with three-dimensional structures. This increases the active material loading while shortening the diffusion distance of alkali metal ions during charging and discharging, accelerating the diffusion rate of alkali metal ions and electrons, and improving battery cycle performance. However, in related technologies, the development of porous silicon electrodes for lithium-ion batteries based on 3D printing technology only investigated the mass ratio of the components in the 3D printing slurry, keeping the printing parameters and morphology constant. This approach neglected the influence of the printing parameters and the macroscopic structure of the three-dimensional electrode on the electrochemical performance of lithium-ion batteries, failing to produce electrodes with stable structures and good conductivity.

[0004] Therefore, it is necessary to develop a biomimetic three-dimensional electrode with good conductivity and stable structure. Summary of the Invention

[0005] To address the problems existing in the prior art, the present invention provides a biomimetic three-dimensional electrode with good conductivity and stable structure.

[0006] The present invention also provides a method for preparing the above-mentioned biomimetic three-dimensional electrode.

[0007] This invention also provides the application of the above-mentioned biomimetic three-dimensional electrode in the preparation of alkali metal batteries.

[0008] The first aspect of the present invention provides a biomimetic three-dimensional electrode, comprising:

[0009] Electrode body;

[0010] The support portion is connected to the electrode body and is symmetrically arranged on both sides of the electrode body. The number of the support portions is at least two, and the support portions are parallel to each other.

[0011] According to at least one embodiment of the present invention, the following beneficial effects are achieved:

[0012] The biomimetic three-dimensional electrode of this invention increases the active material loading while simultaneously shortening the diffusion distance of alkali metal ions during charging and discharging, thus accelerating the diffusion rate of alkali metal ions and electrons (unlike the flat electrode in related technologies that increases the active material loading by increasing the coating thickness, i.e., the flat electrode extends the diffusion path of alkali metal ions in the electrode by increasing the thickness; the biomimetic three-dimensional electrode of this invention has a higher specific surface area, and alkali metal ions can diffuse from multiple directions, which is superior to the flat electrode). Furthermore, a centipede-like "leg" structure is added to the ordinary array line structure to support the array line electrode and enhance the mechanical stability of the three-dimensional electrode. The "leg" structure, composed mainly of a conductive agent slurry, also improves the conductivity of the electrode, thereby improving the cycle performance and rate performance of the battery.

[0013] According to some embodiments of the present invention, both the electrode body and the support portion are prepared by 3D printing.

[0014] According to some embodiments of the present invention, the biomimetic three-dimensional electrode has a centipede-like structure.

[0015] According to some embodiments of the present invention, the electrode body is a three-dimensional electrode line array.

[0016] The length of the electrode wires is unlimited, and the specific length depends on the diameter of the electrode sheet used. The width and height are related to the printing parameters used in 3D printing, and the spacing between adjacent electrode wires is related to the printing interval set in 3D printing.

[0017] According to some embodiments of the present invention, the width of the electrode body is 0.1 mm to 2 mm.

[0018] According to some embodiments of the present invention, the spacing between the three-dimensional electrode lines is 2 to 8 times the width of the electrode body.

[0019] The gaps between the electrode array lines are extruded during the 3D printing process.

[0020] If the spacing of the "body" structure is too small, it will not provide enough space for printing the subsequent "legs" structure. At the same time, the size of the electrode sheet must be considered, and the spacing cannot be too large. It is sufficient to take 2 to 8 times its width.

[0021] According to some embodiments of the present invention, the three-dimensional electrode line array is composed of a plurality of three-dimensional electrode lines.

[0022] According to some embodiments of the present invention, the diameter of the three-dimensional electrode wire is 0.5 mm to 0.7 mm.

[0023] According to some embodiments of the present invention, the diameter of the three-dimensional electrode wire is 0.55 mm to 0.68 mm.

[0024] According to some embodiments of the present invention, the spacing between adjacent three-dimensional electrode lines is 1.8 mm to 2.2 mm.

[0025] According to some embodiments of the present invention, the interval between adjacent three-dimensional electrode lines is 2 mm.

[0026] According to some embodiments of the present invention, the diameter of the support portion is 0.1 to 1 times the diameter of the electrode wire.

[0027] According to some embodiments of the present invention, the interval between adjacent support portions is 1 to 10 times the diameter of the support portion.

[0028] According to some embodiments of the present invention, the diameter of the support portion is 0.4 mm to 0.5 mm.

[0029] According to some embodiments of the present invention, the diameter of the support portion is 0.44 mm.

[0030] According to some embodiments of the present invention, the interval between adjacent support portions is 1.5 mm to 2 mm.

[0031] Based on the physical characteristics of centipedes in nature, it is known that the legs of centipedes are all smaller than the width of their bodies. Therefore, the diameter of the array electrode lines is chosen as the benchmark for measuring the diameter of the "leg" structure, ranging from 10% to 100% of its diameter.

[0032] If the spacing between the "steps" is too small, it will cause the electrode paste to stick together, reduce the surface area of ​​the three-dimensional electrode, and thus reduce the conductivity of the electrode. At the same time, the size of the electrode sheet must also be considered, and the spacing cannot be too large. Therefore, the spacing between the "steps" is 1 to 10 times its diameter.

[0033] According to some embodiments of the present invention, the raw materials for preparing the electrode body include: electrode material, conductive agent I, binder I, and solvent I.

[0034] According to some embodiments of the present invention, the raw materials for preparing the electrode body include the following parts by weight: 60 to 90 parts of electrode material, 5 to 20 parts of conductive agent I, and 5 to 20 parts of binder I.

[0035] According to some embodiments of the present invention, the electrode material is an alkali metal battery electrode material.

[0036] According to some embodiments of the present invention, the alkali metal battery electrode material includes lithium-ion electrode material and sodium-ion electrode material.

[0037] According to some embodiments of the present invention, the lithium-ion cathode material is at least one of lithium iron phosphate, lithium manganese phosphate, lithium manganese oxide, lithium iron silicate, lithium manganese silicate, lithium nickel cobalt manganese oxide, lithium nickel manganese oxide, or lithium titanate.

[0038] According to some embodiments of the present invention, the sodium ion electrode material includes at least one of hard carbon and titanium dioxide.

[0039] According to some embodiments of the present invention, the conductive agent I includes at least one selected from acetylene black, carbon black, graphene, carbon fiber, carbon nanotubes, Fe powder, Cu powder, Ag powder, and Ni powder.

[0040] According to some embodiments of the present invention, the adhesive I comprises at least one of polytetrafluoroethylene, low-density polyethylene, polyvinylidene fluoride, and polyvinyl alcohol.

[0041] According to some embodiments of the present invention, solvent I comprises water or N-methylpyrrolidone.

[0042] According to some embodiments of the present invention, the raw materials for preparing the support portion include: conductive agent II, adhesive II, and solvent II.

[0043] According to some embodiments of the present invention, the conductive agent II includes at least one selected from acetylene black, carbon black, graphene, carbon fiber, carbon nanotubes, Fe powder, Cu powder, Ag powder, and Ni powder.

[0044] According to some embodiments of the present invention, the adhesive II comprises at least one of polytetrafluoroethylene, low-density polyethylene, polyvinylidene fluoride, and polyvinyl alcohol.

[0045] According to some embodiments of the present invention, solvent II comprises water or N-methylpyrrolidone.

[0046] The second aspect of the present invention provides a method for preparing the above-mentioned biomimetic three-dimensional electrode, wherein the electrode body is printed on the surface of the current collector using a 3D printing device, the support part is printed using a 3D printing device, and then dried to obtain the electrode.

[0047] The drying temperature is 50℃~150℃, and the drying time is 3h~12h.

[0048] According to at least one embodiment of the present invention, the following beneficial effects are achieved:

[0049] This invention combines biomimetic principles with 3D printing to create a biomimetic three-dimensional electrode. The 3D-printed centipede-like biomimetic three-dimensional electrode provided by this invention includes a centipede-like "body" and supporting "legs" on both sides. The "body" structure is a 3D-printed three-dimensional array line structure; the "legs" are 3D-printed structures perpendicular to the "body," providing support and enhancing conductivity. The fabrication process of the biomimetic three-dimensional electrode provided by this invention is simple, improving battery performance simply by modifying the three-dimensional electrode structure, which is beneficial for large-scale production and widespread application.

[0050] According to some embodiments of the present invention, the 3D printing apparatus includes a 3D printing substrate cylinder; the 3D printing substrate cylinder is connected to a first nozzle; and the 3D printing substrate cylinder is connected to a second nozzle.

[0051] The diameter of the nozzle used for 3D printing varies from 0.05mm to 5mm, while the diameter of the electrode sheet of the button cell is 12mm to 15mm. Therefore, the diameter of the nozzle selected cannot be too large, so the width of the centipede "body" structure produced is 0.1mm to 2mm.

[0052] According to some embodiments of the present invention, the current collector includes one of copper foil, aluminum foil, nickel foam, copper foam, and carbon cloth.

[0053] According to some embodiments of the present invention, the thickness of the current collector is 35 μm to 2000 μm.

[0054] According to some embodiments of the present invention, the method for preparing the electrode body includes the following steps: mixing the electrode material, the conductive agent I, the binder I and the solvent I and then degassing to obtain a first mixed slurry; adding the first mixed slurry into a 3D printing base cylinder and printing using the first nozzle of a 3D printing device.

[0055] According to some embodiments of the present invention, the mixing speed is 2000 rpm to 3000 rpm.

[0056] According to some embodiments of the present invention, the mixing time is 10 min to 60 min.

[0057] According to some embodiments of the present invention, the stirring speed for degassing is 1000 rpm to 3000 rpm.

[0058] According to some embodiments of the present invention, the degassing time is 5 min to 60 min.

[0059] According to some embodiments of the present invention, the diameter of the first nozzle is 100 μm to 1000 μm.

[0060] According to some embodiments of the present invention, the printing speed of the first printhead is 5 mm / s to 80 mm / s.

[0061] According to some embodiments of the present invention, the printing pressure of the first printhead is 10 pis to 60 pis.

[0062] According to some embodiments of the present invention, the height at which the first nozzle contacts the collector is raised by 0.1 mm to 1 mm.

[0063] According to some embodiments of the present invention, the method for preparing the support includes the following steps: mixing the conductive agent I, the adhesive I and the solvent I and then degassing to obtain a second mixed slurry; adding the second mixed slurry into a 3D printing base cylinder and printing using the second nozzle of a 3D printing device.

[0064] According to some embodiments of the present invention, the mixing speed is 2000 rpm to 3000 rpm.

[0065] According to some embodiments of the present invention, the mixing time is 10 min to 60 min.

[0066] According to some embodiments of the present invention, the stirring speed for degassing is 1000 rpm to 3000 rpm.

[0067] According to some embodiments of the present invention, the degassing time is 5 min to 60 min.

[0068] According to some embodiments of the present invention, the diameter of the second nozzle is 100 μm to 600 μm.

[0069] According to some embodiments of the present invention, the diameter of the second nozzle is 10% to 50% of the diameter of the first nozzle.

[0070] According to some embodiments of the present invention, the printing speed of the second printhead is 5 mm / s to 80 mm / s.

[0071] This printing speed improves print quality and energy density.

[0072] According to some embodiments of the present invention, the printing pressure of the second printhead is 10 pis to 60 pis.

[0073] According to some embodiments of the present invention, the contact point between the second nozzle and the collector is raised by 0.1 mm to 1 mm.

[0074] According to some embodiments of the present invention, the lifting height at the contact point between the second nozzle and the electrode body is 0.1 mm to 1 mm.

[0075] Since the purpose of preparing the centipede-like "leg" structure is to improve the conductivity of the three-dimensional electrode and support the three-dimensional array line electrode "body" structure, thereby improving the mechanical stability and conductivity of the three-dimensional electrode, the lifting height of the contact point between the second nozzle and the three-dimensional array line electrode of the centipede-like "body" structure (electrode body) should be slightly lower than the lifting height of other contact points (0.8-1 times the lifting height of other contact points). This will have a compacting effect on the "body" structure, ensuring close contact between the "legs" and the "body" and mutual support.

[0076] A third aspect of the present invention provides an alkali metal battery, comprising the above-described biomimetic three-dimensional electrode.

[0077] According to at least one embodiment of the present invention, the following beneficial effects are achieved:

[0078] 1. The biomimetic three-dimensional electrode (3D printed centipede-like structure) provided by this invention increases the active material loading, thereby improving the power density of alkali metal ion batteries, compared with traditional flat plate electrodes. At the same time, it also shortens the diffusion distance of alkali metal ions during charging and discharging, accelerates the diffusion rate of alkali metal ions and electrons, improves the conductivity of the electrode, and enhances the cycle performance of alkali metal batteries.

[0079] 2. The biomimetic three-dimensional electrode provided by the present invention has a "leg" structure perpendicular to the centipede-like "body" structure, which supports the "body" structure of the centipede-like electrode, improves the mechanical stability of the three-dimensional electrode, and thus prevents the three-dimensional collapse, thereby improving the cycle performance of the alkali metal battery.

[0080] 3. The biomimetic three-dimensional electrode provided by this invention has a "foot" structure that is 3D printed using a mixture of conductive agent, binder and solvent, which improves the conductivity of the three-dimensional electrode, thereby reducing the impedance of the alkali metal battery and improving the rate performance of the battery. Attached Figure Description

[0081] Figure 1 This is a schematic diagram of the structure of the biomimetic three-dimensional electrode obtained in Embodiment 1 of the present invention.

[0082] Figure 2 This is a schematic diagram of the assembly of a lithium-ion half-cell with a biomimetic three-dimensional electrode obtained in Embodiment 2 of the present invention.

[0083] Figure 3 The graphs show the cycle performance of lithium-ion half-cells based on a 3D-printed centipede-like biomimetic three-dimensional electrode prepared in Example 2 of the present invention, a three-dimensional array line electrode prepared in Comparative Example 1 of the present invention, and a planar electrode prepared in Comparative Example 2 of the present invention under a 5C charge-discharge rate current condition.

[0084] Figure 4The graph shows a comparison of the rate performance of lithium-ion half-cells based on a 3D-printed centipede-like biomimetic three-dimensional electrode prepared in Example 2 of the present invention, a three-dimensional array line electrode prepared in Comparative Example 1 of the present invention, and a planar electrode prepared in Comparative Example 2 of the present invention.

[0085] Figure 5 This is a schematic diagram of the structure of the three-dimensional array line electrode in Comparative Example 1 of the present invention.

[0086] Figure label:

[0087] 1-Three-dimensional array line structure, 2-"walking" structure, 3-Upper battery case, 4-Push pad, 5-Spring piece, 6-Lithium sheet, 7-Lower battery case, 8-Electrolyte, 9-Electrode sheet, 10-Separator. Detailed Implementation

[0088] The following will describe the concept and technical effects of the present invention clearly and completely with reference to embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention.

[0089] In the description of this invention, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0090] The specific embodiments of the present invention are described in detail below.

[0091] In the embodiments of this invention, lithium titanate, conductive carbon black, and polyvinylidene fluoride were all purchased from Shenzhen Kejing Co., Ltd.

[0092] In this embodiment of the invention, the length and width of the foamed nickel match the material stage size of the 3D printer (15cm long * 10cm wide), and the manufacturer is Kunshan Guangjiayuan Electronic Materials Business Department.

[0093] Example 1

[0094] A method for fabricating a biomimetic three-dimensional electrode includes the following steps:

[0095] S1. Slurry preparation:

[0096] Weigh 7g of lithium titanate, 2g of conductive carbon black and 1g of polyvinylidene fluoride, and then measure 17mL of N-methylpyrrolidone into the special material cup of the high-speed mixer. Process the mixture at 3000rpm for 10min to achieve uniform mixing. Then degas at 3000rpm for 5min to obtain a uniformly mixed first slurry.

[0097] Weigh 1g of conductive carbon black and 1g of polyvinylidene fluoride, and then measure 17mL of N-methylpyrrolidone into the special material cup of the high-speed mixer. Use the high-speed mixer at 2000rpm for 20min to mix evenly. Then degas at 3000rpm for 5min to obtain a uniformly mixed second slurry.

[0098] S2, 3D printing to create the centipede-like "body" structure:

[0099] A 0.5 cm thick nickel foam was used as the current collector for the three-dimensional electrode. The first mixed slurry prepared in step S1 was used as the slurry for 3D printing and placed in the 3D printing base cylinder. The diameter of the first nozzle was 500 μm. The printing parameters were set (printing speed 20 mm / s, air pressure 45 psi, array line printing interval 2 mm, and the lifting height of the first nozzle at the contact point with the nickel foam was 0.5 mm) to create a centipede-like three-dimensional array line electrode.

[0100] S2, 3D printing to create centipede-like "leg" structures:

[0101] The second mixed slurry prepared in step S1 is used as the slurry for 3D printing and placed in the 3D printing base cylinder. The diameter of the second nozzle is 400μm. The printing parameters are set (printing speed 15mm / s, air pressure 25psi, "leg" structure printing interval 2mm, lifting height of the second nozzle at the contact point with the nickel foam 0.4mm, lifting height of the second nozzle at the contact point with the three-dimensional array line electrode of the centipede-like "body" structure prepared in step S2 0.3mm). The "leg" structure perpendicular to the array line electrode is printed on the three-dimensional array line electrode of the centipede-like "body" structure prepared in step S2.

[0102] S4. The three-dimensional electrode with a centipede-like "body" and "legs" structure prepared in step S3 is dried at a temperature of 60°C for 10 hours to obtain a biomimetic three-dimensional electrode.

[0103] A schematic diagram of the structure of the biomimetic three-dimensional electrode fabricated in this embodiment is shown below. Figure 1 As shown, please refer to Figure 1As shown, the biomimetic three-dimensional electrode includes a centipede-like "body" 1 and "legs" 2 structures; the "body" 1 is a three-dimensional array line structure prepared by 3D printing; the "legs" 2 are 3D printed structures perpendicular to the "body", which play a supporting and enhancing role in conductivity.

[0104] In this embodiment, the diameter of the three-dimensional array line of the centipede-like "body" structure is about 550 μm, and the diameter of the "leg" structure perpendicular to the array line electrode is about 440 μm.

[0105] Example 2

[0106] A method for fabricating a biomimetic three-dimensional electrode includes the following steps:

[0107] S1. Slurry preparation:

[0108] Weigh 8g of lithium titanate, 1g of conductive carbon black and 1g of polyvinylidene fluoride, and then measure 15mL of N-methylpyrrolidone into the special material cup of the high-speed mixer. Use the high-speed mixer at 3000rpm for 30min to mix evenly, and then degas at 3000rpm for 5min to obtain the first mixed slurry.

[0109] Weigh 1g of conductive carbon black and 1g of polyvinylidene fluoride, and measure 17mL of N-methylpyrrolidone into a special material cup for a high-speed mixer. Process the mixture at 3000rpm for 30min, and then degas at 3000rpm for 5min to obtain the second mixed slurry.

[0110] S2, 3D printing to create the centipede's "body" structure:

[0111] A 0.5 cm thick nickel foam was used as the current collector for the three-dimensional electrode. The first mixed slurry prepared in step S1 was used as the slurry for 3D printing and placed in the 3D printing base cylinder with a first diameter of 600 μm. The printing parameters were set (printing speed 25 mm / s, air pressure 40 psi, array line printing interval 2 mm, and the lifting height of the first nozzle at the contact point with the nickel foam 0.6 mm) to create a three-dimensional array line electrode with a centipede-like "body" structure.

[0112] S3, 3D printing to create centipede-like "leg" structures:

[0113] The second mixed slurry prepared in step S1 is used as the slurry for 3D printing and placed in the 3D printing base cylinder with a second diameter of 400 μm. The printing parameters are set as follows: printing speed 15 mm / s, air pressure 30 psi, lifting height of the second nozzle at the contact point with the nickel foam 0.4 mm, "leg" structure printing interval 1.5 mm, lifting height of the second nozzle at the contact point with the nickel foam 0.4 mm, and lifting height of the nozzle at the contact point with the three-dimensional array line electrode of the centipede-like "body" structure prepared in step S2 0.3 mm. "Leg" structures perpendicular to the array line electrodes are printed on the three-dimensional array line electrode of the centipede-like "body" structure prepared in step S2.

[0114] S4. The three-dimensional electrode with a centipede-like "body" and "legs" structure prepared in step S3 is dried at a temperature of 60°C for 12 hours to obtain a biomimetic three-dimensional electrode.

[0115] A schematic diagram of the biomimetic three-dimensional electrode obtained in Example 2 is shown in the figure below. Figure 1 As shown, the biomimetic three-dimensional electrode includes a centipede-like "body" 1 and "legs" 2 structures; the "body" 1 is a three-dimensional array line structure prepared by 3D printing; the "legs" 2 are 3D printed structures perpendicular to the "body", which play a supporting and enhancing role in conductivity.

[0116] In this embodiment, the diameter of the three-dimensional array line of the centipede-like "body" structure is about 680 μm, and the diameter of the "leg" structure perpendicular to the array line electrode is about 440 μm.

[0117] Example 3

[0118] This embodiment is a lithium-ion battery. The positive electrode of the lithium-ion battery in this embodiment adopts the biomimetic three-dimensional electrode (3D printed centipede-like biomimetic three-dimensional electrode) prepared in Example 2, and the lithium sheet is used as the negative electrode. When assembling the battery, the centipede-like structure of the biomimetic three-dimensional electrode prepared in Example 2 is in direct contact with the separator, and the substrate nickel foam is in direct and tight contact with the battery shell.

[0119] Figure 2 This is a schematic diagram of the lithium-ion half-cell assembly in this embodiment, as shown below. Figure 2 As shown, electrode 9 is placed on the lower battery casing 7, and electrolyte 9 directly wets the active material on the electrode 9. Electrolyte 8 (1 mol / L lithium hexafluorophosphate solution) fills the entire cavity composed of electrode 9, lower battery casing 7, and separator 10. Lithium sheet 6 is tightly attached to separator 10. From bottom to top, gasket 4 and spring sheet 5 are placed on the upper surface of lithium sheet 6. Gasket 4 and spring sheet 5 are used to adjust the battery pressure. Spring sheet 5 is in close contact with upper battery casing 3 to reduce contact resistance and ensure good conductivity inside the battery.

[0120] In this embodiment, during the discharge of the lithium-ion half-cell based on a biomimetic three-dimensional electrode, lithium sheet 6 begins to delithigate, and lithium ions enter the electrolyte 8 through the separator 10. Subsequently, they contact the active material on electrode sheet 9, undergoing a lithium intercalation reaction. Simultaneously, electrons pass through pad 4, spring 5, and upper battery shell 3 into lower battery shell 7. Because lower battery shell 7 is in close contact with electrode sheet 9, electrons then enter the active material of electrode sheet 9 to neutralize the charge of lithium ions, completing the discharge process of the lithium-ion half-cell. During charging, lithium ions first detach from the active material on electrode sheet 9 and enter the electrolyte 8, then contact lithium sheet 6 through separator 10. Electrons are transferred from the active material on electrode sheet 9 and pass through lower battery shell 7, upper battery shell 3, spring 5, and pad 4 to achieve charge balance with the lithium ions on lithium sheet 6, completing the charging process.

[0121] The cycle performance and rate performance of the lithium-ion half-cell based on the 3D-printed centipede-like biomimetic three-dimensional electrode prepared in Example 3 were tested using the LAND CT2001A battery testing system (all tests were conducted at room temperature (25°C) with a voltage range of 1V to 3V).

[0122] Comparative Example 1

[0123] This comparative example is a lithium-ion half-cell based on a three-dimensional array of linear electrodes.

[0124] The electrode material for this comparative example was prepared using the following raw materials: 8g lithium titanate, 1g conductive carbon black, 1g polyvinylidene fluoride, and 15mL N-methylpyrrolidone.

[0125] The fabrication method of the three-dimensional array line electrode in this comparative example consists of the following steps:

[0126] S1. Slurry preparation:

[0127] Weigh 8g of lithium titanate, 1g of conductive carbon black and 1g of polyvinylidene fluoride, and then measure 15mL of N-methylpyrrolidone into a special material cup for a high-speed mixer. Use a high-speed mixer at 3000rpm for 30min to mix evenly, and then degas at 3000rpm for 5min to obtain a mixed slurry.

[0128] S2, 3D printing:

[0129] A 0.5 cm thick nickel foam was used as the current collector for the three-dimensional electrode. The mixed slurry prepared in step S1 was used as the slurry for 3D printing. It was placed in a 3D printing base tube with a diameter of 600 μm. The printing parameters were set (printing speed 25 mm / s, air pressure 40 psi, array line printing interval 2 mm, nozzle lifting height at the contact point with the nickel foam 0.6 mm) to manufacture a three-dimensional array line electrode.

[0130] S3. The three-dimensional electrode prepared in step S2 is dried at a temperature of 60°C for 12 hours to obtain a three-dimensional array line.

[0131] In this comparative example, the diameter of the three-dimensional array line is approximately 680 μm. A schematic diagram of the specific structure is shown below. Figure 5 As shown.

[0132] The assembly diagram of the lithium-ion half-cell in this comparative example is shown below. Figure 2 The assembly method is as described in Example 3.

[0133] Comparative Example 2

[0134] This comparative example is a lithium-ion half-cell based on a planar electrode.

[0135] The electrode material for this comparative example was prepared using the following raw materials: 8g lithium titanate, 1g conductive carbon black, 1g polyvinylidene fluoride, and 15mL N-methylpyrrolidone.

[0136] Weigh 8g of lithium titanate, 1g of conductive carbon black and 1g of polyvinylidene fluoride, and then measure 15mL of N-methylpyrrolidone into a special material cup for a high-speed mixer. Use a high-speed mixer at 3000rpm for 30min to mix evenly, and then degas at 3000rpm for 5min to obtain a mixed slurry.

[0137] The electrode material for this comparative example was coated using an automatic coating machine as the coating equipment for the flat electrode. Nickel foam was selected as the current collector. The electrode was placed flat on the sample stage of the automatic coating machine. A 100μm four-sided coater was used to apply the mixed slurry to one side of the four-sided coater. The automatic coating machine was then started, and the four-sided coater was driven to uniformly coat the slurry onto the nickel foam (coating thickness of 100μm). After coating, the electrode was dried at 60℃ for 12 hours.

[0138] The assembly diagram of the lithium-ion half-cell in this comparative example is shown below. Figure 2 .

[0139] from Figure 3 It can be seen that the lithium-ion half-battery based on the 3D-printed centipede-like biomimetic three-dimensional electrode, under the charge-discharge rate current of 5C, has an initial discharge specific capacity of up to 158.1 mAh / g. After 200 cycles, its reversible capacity is still 128.2 mAh / g, with a capacity retention rate of 81.1%.

[0140] Under the same testing conditions, the reversible capacity of the lithium-ion half-cell based on the three-dimensional array line electrode is only 101.1 mAh / g, and the capacity retention rate is only 72.3%.

[0141] The reversible capacity of the lithium-ion half-cell based on planar electrodes is only 66.8 mAh / g, and the capacity retention rate is only 51.2%. The results show that the 3D-printed centipede-like biomimetic three-dimensional electrode not only improves the charge-discharge specific capacity of the battery, but also effectively enhances the cycle stability of the battery, thereby improving the cycle life of the battery.

[0142] The 3D-printed centipede-like biomimetic three-dimensional electrode prepared in Example 1 has similar effects to that in Example 2, and its cycle performance can be referenced. Figure 3 As shown.

[0143] The rate performance comparison curves of the lithium-ion half-cells based on the 3D-printed centipede-like biomimetic three-dimensional electrodes are shown in the figure below. Figure 4 As shown. By Figure 4 As can be seen, under rate cycling at 0.5C, 1C, 2C, 5C, 10C and 0.5C, the discharge specific capacity based on the 3D-printed centipede-like biomimetic three-dimensional electrode is 175.3mAh / g, 173.7mAh / g, 170.3mAh / g, 159.6mAh / g, 126.6mAh / g and 174.5mAh / g, respectively. This is much higher than that of lithium-ion half-cells based on three-dimensional array line electrodes (160.5mAh / g, 160.6mAh / g, 154.9mAh / g, 142.8mAh / g, 91.4mAh / g and 160mAh / g) and lithium-ion batteries based on planar electrodes (149.3mAh / g, 146.3mAh / g, 141.2mAh / g, 126.9mAh / g, 85.7mAh / g and 149.5mAh / g). At lower rate cycling, the specific capacity of the three-dimensional array line electrode is significantly improved compared to the planar electrode, but the capacity decays drastically under high current cycling at 10C. However, the 3D-printed centipede-like biomimetic three-dimensional electrode still maintains a high discharge specific capacity of 126.6 mAh / g at a high rate current of 10C, which is 38.5% higher than that of the three-dimensional array line electrode. The results indicate that the centipede-like biomimetic structure with three-dimensional array line composite conductive "legs" effectively improves the rate performance of lithium-ion batteries, especially at high rate currents.

[0144] The biomimetic three-dimensional electrode (3D-printed centipede-like structure) prepared in Example 1 has similar effects to that in Example 2, and its rate performance can be referenced. Figure 4 As shown.

[0145] In summary, the lithium-ion half-cell based on a 3D-printed centipede-like biomimetic three-dimensional electrode provided by this invention exhibits significantly improved electrochemical performance compared to lithium-ion half-cells based on three-dimensional array line electrodes and planar electrodes, with superior cycle stability, longer cycle life, and better rate performance.

[0146] The embodiments described above are merely illustrative examples to explain the present invention and are not intended to limit the implementation of the present invention. Any changes, improvements, substitutions, etc., made by those skilled in the art without departing from the innovative concept of the present invention shall fall within the protection scope of the present invention.

[0147] The embodiments of the present invention have been described in detail above with reference to specific implementation methods. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A biomimetic three-dimensional electrode, characterized by: include: The electrode body is a three-dimensional electrode line array, and the raw materials for preparing the electrode body include: electrode material, conductive agent I, binder I and solvent I; The support portion is connected to the electrode body and is symmetrically arranged on both sides of the electrode body. There are at least two support portions, which are parallel to each other. The diameter of the support portion is 0.1 to 1 times the diameter of the electrode wire. The raw materials for preparing the support portion include: conductive agent II, adhesive II and solvent II. The biomimetic three-dimensional electrode has a centipede-like structure, and the electrode body and support are printed by a 3D printing device.

2. The biomimetic three-dimensional electrode according to claim 1, wherein: The width of the electrode body is 0.1mm to 2mm.

3. The biomimetic three-dimensional electrode according to claim 1, wherein: The spacing between the three-dimensional electrode line arrays is 2 to 8 times the width of the electrode body.

4. The biomimetic three-dimensional electrode according to claim 1, wherein: The interval between adjacent support portions is 1 to 10 times the diameter of the support portion.

5. The biomimetic three-dimensional electrode according to any one of claims 1 to 4, characterized in that: The raw materials for preparing the electrode body include the following parts by weight: 60 to 90 parts of electrode material, 5 to 20 parts of conductive agent I, and 5 to 20 parts of adhesive I.

6. The biomimetic three-dimensional electrode according to claim 1, wherein: The electrode material is an alkali metal battery electrode material.

7. The biomimetic three-dimensional electrode according to claim 6, characterized in that: The alkali metal battery electrode materials include lithium-ion electrode materials and sodium-ion electrode materials.

8. The biomimetic three-dimensional electrode according to claim 7, characterized in that: The lithium-ion electrode material is at least one of lithium iron phosphate, lithium manganese phosphate, lithium manganese oxide, lithium iron silicate, lithium manganese silicate, lithium nickel cobalt manganese oxide, lithium nickel manganese oxide, or lithium titanate.

9. The biomimetic three-dimensional electrode according to claim 7, wherein: The sodium ion electrode material includes at least one of hard carbon and titanium dioxide.

10. The biomimetic three-dimensional electrode according to claim 1, wherein: The conductive agent I includes at least one of acetylene black, carbon black, graphene, carbon fiber, carbon nanotubes, Fe powder, Cu powder, Ag powder, and Ni powder.

11. The biomimetic three-dimensional electrode according to claim 1, wherein: The adhesive I includes at least one of polytetrafluoroethylene, low-density polyethylene, polyvinylidene fluoride, and polyvinyl alcohol.

12. The biomimetic three-dimensional electrode according to claim 1, wherein: Solvent I includes water or N-methylpyrrolidone.

13. The biomimetic three-dimensional electrode according to claim 1, wherein: The conductive agent II includes at least one of acetylene black, carbon black, graphene, carbon fiber, carbon nanotubes, Fe powder, Cu powder, Ag powder, and Ni powder.

14. The biomimetic three-dimensional electrode according to claim 1, wherein: The adhesive II includes at least one of polytetrafluoroethylene, low-density polyethylene, polyvinylidene fluoride, and polyvinyl alcohol.

15. The biomimetic three-dimensional electrode according to claim 1, wherein: Solvent II includes water or N-methylpyrrolidone.

16. A method of preparing a biomimetic three-dimensional electrode according to any one of claims 1 to 15, characterized in that: The electrode body is printed on the surface of the current collector using a 3D printing device, and the support part is printed using a 3D printing device and then dried. The drying temperature is 50℃~150℃, and the drying time is 3h~12h.

17. The method of claim 16, wherein: The current collector includes one of copper foil, aluminum foil, nickel foam, copper foam, and carbon cloth.

18. The method of claim 16, wherein: The thickness of the current collector is 35μm~2000μm.

19. The method of claim 16, wherein: The 3D printing device includes a 3D printing base material cylinder; the 3D printing base material cylinder is connected to a first nozzle; the 3D printing base material cylinder is connected to a second nozzle.

20. The method of claim 16, wherein: The method for preparing the electrode body includes the following steps: mixing the electrode material, the conductive agent I, the adhesive I and the solvent I and then degassing to obtain a first mixed slurry; adding the first mixed slurry into a 3D printing base cylinder and printing using the first nozzle of a 3D printing device.

21. The method of claim 20, wherein: The mixing speed is 2000 rpm to 3000 rpm.

22. The method of claim 20, wherein: The mixing time is 10 min to 60 min.

23. The method of claim 20, wherein: The stirring speed of the defoaming is 1000rmp-3000rpm.

24. The method of claim 20, wherein: The defoaming time is 5min-60min.

25. The method of claim 16, wherein: The preparation method of the support part comprises the following steps: mixing the conductive agent I, the adhesive I and the solvent I, defoaming to obtain a second mixed slurry, and adding the second mixed slurry into a 3D printing base material cylinder and printing by using a first nozzle of a 3D printing device.

26. The method of claim 25, wherein: The stirring speed of the mixing is 2000rmp-3000rpm.

27. The method of claim 25, wherein: The mixing time is 10min-60min.

28. The method of claim 25, wherein: The stirring speed of the defoaming is 1000rmp-3000rpm.

29. The method of claim 25, wherein: The defoaming time is 5min-60min.

30. An alkali metal battery characterized by: The bionic three-dimensional electrode comprises a three-dimensional electrode body and a three-dimensional electrode support part. The bionic three-dimensional electrode comprises a three-dimensional electrode body and a three-dimensional electrode support part.

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