Preparation method of solid-state lithium battery electrode honeycomb bionic structure

Abstract

The invention relates to the technical field of solid-state lithium batteries, and discloses a preparation method of a solid-state lithium battery electrode honeycomb bionic structure, which comprises the following steps: depositing a layer of high-entropy metal-organic matter amorphous precursor film on an electrode current collector substrate; in an inert gas environment, single-time picosecond pulse laser is adopted to irradiate the precursor film, and after the laser pulse is shaped by a spatial light modulator, a honeycomb-shaped grid interference pattern is formed on the surface of the film. And the pattern induces the precursor film to be subjected to phase separation and self-assembly, so that a three-dimensional honeycomb framework which is integrally metallurgically bonded with the electrode current collector substrate is formed. The invention also discloses the solid-state lithium battery electrode prepared by the method. Through non-contact laser processing, mechanical damage to the current collector substrate is avoided; the formed metallurgical bonding interface effectively reduces the interface contact resistance of the electrode; meanwhile, accurate digital control over geometric parameters of the honeycomb structure is achieved through the spatial light modulator.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solid-state lithium batteries, in particular to a preparation method of a honeycomb biomimetic structure of a solid-state lithium battery electrode. BACKGROUND

[0002] To meet the demand for high energy density and high safety energy storage devices, solid-state lithium batteries have become an important technical development direction. In solid-state lithium batteries, the structural design of the electrode has a direct impact on the overall electrochemical performance. In order to improve the performance of the electrode, various three-dimensional structure electrodes have been developed in the prior art, aiming to increase the contact area between the electrode and the electrolyte, shorten the diffusion path of ions in the active material, and buffer the volume change of the active material during the charging and discharging process, to improve the rate performance and cycle stability of the battery.

[0003] Currently, the method for preparing a three-dimensional structure electrode generally includes pre-constructing a three-dimensional skeleton on the electrode current collector substrate. A common technical path is to use mechanical rolling, stamping or etching and other physical methods to form a pit or groove array on the surface of the current collector. However, such mechanical processing process will introduce residual stress and micro defects in the metal current collector, which may affect its long-term mechanical stability and conductivity.

[0004] After forming the three-dimensional skeleton structure, the electrode active material needs to be filled therein. The conventional process is to mix the active material powder with the conductive agent and the binder to form a slurry, and then fill it into the preformed three-dimensional structure by coating. The interface between the active material and the current collector skeleton formed by this method is a physical contact interface. At this interface, the transmission of electrons depends on the point contact between the active material particles and the current collector, as well as the particles and particles, and the presence of the binder which does not have conductivity at the interface will further increase the interface contact resistance. During the battery cycle, the significant volume change of the active material will continuously act on this physical contact interface, which may cause the active material particles to peel off from the surface of the current collector or the conductive network between the particles to be damaged, thereby causing the capacity of the electrode to decay. In addition, the preparation method using a physical mold is limited in the structure geometry that can be formed by the machining precision and types of the mold, and adjusting the structure parameters requires redesigning and manufacturing the mold, which lacks flexibility in the process. SUMMARY

[0005] In view of the deficiencies of the prior art, the present application provides a preparation method of a honeycomb biomimetic structure of a solid-state lithium battery electrode, which solves the problems that mechanical stress and micro damage are introduced into the current collector when a three-dimensional structure electrode is prepared by mechanical rolling and other methods in the prior art, the interface between the current collector and the subsequently filled active material is a physical contact, the interface bonding force is limited, and the geometry of the structure is limited by the precision and types of the physical mold.

[0006] To achieve the above object, the present application is implemented by the following technical solutions: A preparation method of a solid-state lithium battery electrode honeycomb biomimetic structure, comprising:

[0007] The present application provides a solid-state lithium battery electrode in the first aspect, which comprises:

[0008] An electrode current collector substrate; and a three-dimensional honeycomb framework composed of a high-entropy alloy arranged on the surface of the electrode current collector substrate.

[0009] The honeycomb pit structure constitutes a 3D storage space (for the positive electrode) or a 3D lithium storage carrier space (for the negative electrode) for accommodating active materials. This structure is formed by physical imprinting, which is different from coating, etching and other methods, and can ensure the integrity and structural strength of the current collector.

[0010] The bottom of the honeycomb framework and the surface of the electrode current collector substrate are integrally combined by metallurgical bonding. This metallurgical bonding is formed when the molten metal components directly solidify on the surface of the electrode current collector substrate in step S2, which is different from the mechanical bonding interface formed by physical pressing or coating. The high-entropy alloy constituting the honeycomb framework is derived from the metal components in the high-entropy metal-organic amorphous precursor film in step S1.

[0011] In a specific embodiment, the electrode current collector substrate can be a copper foil or an aluminum foil. When used as a positive electrode, the electrode current collector substrate is an aluminum foil, and the depth of the honeycomb pit structure on the surface thereof can be 3-8 μm.

[0012] In a specific embodiment, when used as a negative electrode, the electrode substrate material can be a lithium-aluminum alloy foil or a lithium metal foil, and the depth of the honeycomb pit structure on the surface thereof can be 10-30 μm. This structure not only adapts to the severe volume change during lithium deposition and stripping, but also promotes the ordered deposition of lithium metal from the bottom of the honeycomb to the top and from the edge to the center through structural guidance, effectively inhibiting the formation of lithium dendrites.

[0013] In a specific embodiment, the honeycomb framework constitutes a plurality of honeycomb units, the diameter of the honeycomb units can be 20-100 μm, and the width of the honeycomb framework constituting the honeycomb units can be 1-5 μm.

[0014] In one specific embodiment, the high-entropy alloy constituting the honeycomb framework can include, in atomic percentage, 50-80 at.% silicon, 10-25 at.% aluminum, and 5-15 at.% nickel. The surface of the metal negative electrode of the solid-state lithium battery of lithium-aluminum alloy or lithium metal material can be processed into a honeycomb-like close-packed structure of blind holes in the aspect, to constitute a 3D lithium storage carrier space with hexagonal framework support and hexahedral containing space. Due to the stable mechanical properties of the honeycomb-like biomimetic structure, the 3D lithium storage carrier space has great space utilization and does not increase the weight of the negative electrode material while ensuring the mechanical strength.

[0015] The second aspect of the present application provides a preparation method of a honeycomb biomimetic structure of a solid-state lithium battery electrode, which comprises the following steps:

[0016] S1, first, an electrode current collector substrate is provided, and a high-entropy metal-organic amorphous precursor thin film with a thickness of 5-30 μm is deposited on the electrode current collector substrate by a magnetron sputtering process. The high-entropy metal-organic amorphous precursor thin film is composed of a metal component and a sacrificial organic component. The metal component is in a thermodynamic metastable state due to its high-entropy characteristic. The sacrificial organic component is a material that can be rapidly decomposed and gasified under a specific energy input.

[0017] In one specific embodiment, the metal component can include, in atomic percentage, 50-80 at.% silicon, 10-25 at.% aluminum, and 5-15 at.% nickel. The sacrificial organic component can account for 2-10 vol.% of the total volume of the thin film, in volume percentage. In another specific embodiment, the process parameters of the magnetron sputtering process can include: a working gas pressure of 0.1-1.0 Pa, and a sputtering power of 100-500 W.

[0018] In one specific embodiment, the sacrificial organic component can be a material known to those skilled in the art that can undergo photochemical or photothermal decomposition under the action of a picosecond laser pulse energy. For example, the sacrificial organic component can be selected as polymethyl methacrylate, which can undergo chain scission and gasification under the action of laser with a specific wavelength and energy density. For another example, the sacrificial organic component can also be selected as a commercially available polymer containing an azide group, such as poly(4-vinylphenyl azide), which is sensitive to ultraviolet or specific wavelength laser energy and can rapidly decompose to release nitrogen. The sacrificial organic component and the metal component can be prepared into a composite target material for magnetron sputtering by conventional techniques such as powder metallurgy hot pressing sintering in the art.

[0019] S2, then, under inert gas environment, the electrode current collector substrate on which the high-entropy metal-organic amorphous precursor thin film is deposited is placed in a laser processing system. The high-entropy metal-organic amorphous precursor thin film is irradiated by laser pulses with a single pulse width of 10-100 ps. The laser pulses are shaped by a spatial light modulator loaded with a digital hologram before irradiating the surface of the precursor thin film. The spatial light modulator re-distributes the energy of the laser pulses in space to form a non-uniform energy distribution field with a preset pattern, i.e. a honeycomb grid interference pattern, on the surface of the precursor thin film, with an energy density of 0.1-0.8 J / cm 2 .

[0020] The energy density of the energy peak area (bright lines) of the honeycomb grid interference pattern is sufficient to trigger the phase separation and self-assembly of the high-entropy metal-organic amorphous precursor thin film: the sacrificial organic component in the area is instantaneously decomposed and vaporized, forming a local high pressure to constitute the cavities of the honeycomb; at the same time, the metal component in the area is instantaneously melted. Under the joint action of surface tension gradient and local air pressure gradient, the molten metal component migrates from the energy peak area to the energy valley area (dark lines), converges and rapidly solidifies to form a three-dimensional network of honeycomb skeleton. Since this process occurs directly on the surface of the electrode current collector substrate, an integrated metallurgical bond is formed between the bottom of the formed honeycomb skeleton and the surface of the electrode current collector substrate.

[0021] In a specific embodiment, the digital hologram can be generated by software based on an iterative Fourier transform algorithm. In another specific embodiment, the inert gas environment can be an argon or nitrogen environment with a pressure of 1.0x10 5 -1.2x10 5 Pa.

[0022] S3, finally, the electrode on which the honeycomb skeleton is formed is post-processed. The post-processing aims to remove possible residues in the process and stabilize the structure of the honeycomb skeleton.

[0023] In a specific embodiment, the post-processing can include: first, plasma cleaning to remove surface residual organic by-products, with an RF power of 20-80 W; then, vacuum thermal stabilization treatment to release the internal stress generated in the rapid solidification process of the honeycomb skeleton, with process parameters including: vacuum degree not worse than 1.0x10 -3 Pa, annealing temperature of 150-300℃, and holding time of 1-4 hours.

[0024] The present application provides a preparation method of a solid-state lithium battery electrode honeycomb biomimetic structure. The present application has the following beneficial effects:

[0025] 1、The preparation method of the present application adopts a non-contact laser induction method to form a three-dimensional structure on the electrode current collector substrate. This process does not involve mechanical rolling or physical stamping, thus avoiding the introduction of residual stress and defects such as microscopic cracks caused by plastic deformation in the electrode current collector substrate, thereby maintaining the original mechanical integrity of the electrode current collector substrate.

[0026] 2、The present application forms an integrated metallurgical bonding interface between the honeycomb framework and the substrate by directly melting and rapidly solidifying on the surface of the electrode current collector substrate. Compared with the interface formed by physical contact or adhesive connection, the metallurgical bonding interface provides a continuous and obstacle-free physical path for electron transmission within the electrode, which helps to reduce the interfacial contact resistance between the honeycomb framework and the current collector.

[0027] 3、The present application uses a spatial light modulator to load a digital hologram to define the geometric morphology of the honeycomb structure, without relying on a specific physical mold. Therefore, the structural parameters such as the diameter, wall thickness and arrangement of the honeycomb cells can be precisely controlled and quickly adjusted by modifying the software design of the digital hologram, providing a process basis for optimizing the three-dimensional structure of the electrode for different application scenarios or performance requirements. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The present application is a three-dimensional honeycomb framework spatial diagram.

[0029] 1、honeycomb framework 1; 2、three-dimensional honeycomb framework; 3、electrode current collector substrate. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0031] Embodiment:

[0032] Embodiment 1

[0033] The present embodiment provides a preparation method of a solid-state lithium battery electrode honeycomb biomimetic structure, the specific steps are as follows:

[0034] A composite target was prepared by mixing metal powder and organic powder through powder metallurgy hot-pressing sintering process. The metal powder included 65 at.% of silicon, 18 at.% of aluminum and 17 at.% of nickel in atomic percentage. The organic powder was polymethyl methacrylate powder, which was 6 vol.% in the mixture.

[0035] An electrolytic copper foil with a thickness of 12 μm was selected as the electrode current collector substrate 3, and after standard cleaning, it was placed in a radio frequency magnetron sputtering system. The composite target prepared in step S1 was used as the source, and under the conditions of a working pressure of 0.6 Pa and a sputtering power of 300 W, sputtering was performed to deposit a high-entropy metal-organic amorphous precursor film with a thickness of 15 μm on the surface of the copper foil substrate.

[0036] The copper foil with the precursor film was placed in a sealed cavity filled with argon with a pressure of 1.1 × 10 5 Pa. A picosecond pulsed laser (pulse width 50 ps, wavelength 1064 nm) was used to shape a single laser pulse through a spatial light modulator loaded with a digital hologram, and project it onto the surface of the precursor film. The digital hologram was used to reconstruct a honeycomb grid interference pattern with a honeycomb cell diameter of 60 μm and a wall width of 3 μm on the surface of the film. The output energy of the laser was adjusted so that the energy density reaching the surface of the film was 0.4 J / cm 2 . The entire surface of the substrate was processed in a step exposure mode.

[0037] The processed electrode was subjected to plasma cleaning, and the process parameters were a radio frequency power of 50 W and an argon environment for 180 seconds. Subsequently, vacuum heat stabilization treatment was performed in a tubular annealing furnace with a vacuum degree of 5.0 × 10 -4 Pa at a temperature of 220 °C, and the holding time was 2 hours, followed by natural cooling in the furnace.

[0038] Example 2

[0039] The present example provides a preparation method of a solid-state lithium battery electrode honeycomb biomimetic structure, which is mainly different from example 1 in that the component proportion and process parameters adopt the lower limit values in the range defined in the claims, and the specific steps are as follows:

[0040] The metal powder component was 50 at.% of silicon, 25 at.% of aluminum and 25 at.% of other metals (in this case, 15 at.% of Ni and 10 at.% of Ti, which still totals a high-entropy system). The sacrificial organic component was poly(4-vinylphenyl azide) powder, which was 2 vol.%.

[0041] Deposition was carried out on an electrolytic copper foil substrate with a thickness of 9 μm. The magnetron sputtering process parameters were: working pressure 0.1 Pa, sputtering power 100 W. The thickness of the finally deposited high-entropy metal-organic amorphous precursor thin film was 5 μm.

[0042] The cavity environment was nitrogen with a pressure of 1.0 x 10 5 Pa. A picosecond pulsed laser (pulse width 10 ps) was used to form a honeycomb grid interference pattern on the surface of the thin film after being shaped by a spatial light modulator, with an energy density of 0.1 J / cm 2 . The corresponding target honeycomb cell diameter was 20 μm, and the wall width was 1 μm.

[0043] The plasma cleaning process parameters were: radio frequency power 20 W, and processing time 60 seconds. The vacuum thermal stabilization treatment process parameters were: annealing temperature 150 °C, and holding time 1 hour.

[0044] Example 3

[0045] This example provides a method for preparing a solid-state lithium battery electrode honeycomb biomimetic structure. The main difference from Example 1 is that the component ratio and process parameters use the upper limit values defined in the claims, and the specific steps are as follows:

[0046] The metal powder component was: 80 at. % silicon, 10 at. % aluminum, and 10 at. % nickel. The sacrificial organic component was polymethyl methacrylate powder, with a volume percentage of 10 vol. %.

[0047] Deposition was carried out on an electrolytic copper foil substrate with a thickness of 15 μm. The magnetron sputtering process parameters were: working pressure 1.0 Pa, sputtering power 500 W. The thickness of the finally deposited high-entropy metal-organic amorphous precursor thin film was 30 μm.

[0048] The cavity environment was argon with a pressure of 1.2 x 10 5 Pa. A picosecond pulsed laser (pulse width 100 ps) was used to form a honeycomb grid interference pattern on the surface of the thin film after being shaped by a spatial light modulator, with an energy density of 0.8 J / cm 2 . The corresponding target honeycomb cell diameter was 100 μm, and the wall width was 5 μm.

[0049] The plasma cleaning process parameters were: radio frequency power 80 W, and processing time 300 seconds. The vacuum thermal stabilization treatment process parameters were: annealing temperature 300 °C, and holding time 4 hours.

[0050] Comparative Example

[0051] Comparative Example 1

[0052] Compared with Example 1, the difference is that the precursor target prepared in step S1 does not contain polymethyl methacrylate powder, but is only composed of metal powder with atomic percentage of 65 at. % silicon, 18 at. % aluminum and 17 at. % nickel. All other steps and process parameters are exactly the same as Example 1.

[0053] Comparative Example 2

[0054] Compared with Example 1, the difference is that in the laser-induced self-assembly process of step S3, the laser energy density is increased to 2.5 J / cm 2 , which is higher than the ablation threshold of the precursor film. All other steps and process parameters are exactly the same as Example 1.

[0055] Comparative Example 3

[0056] Compared with Example 1, the difference is that in the laser-induced self-assembly process of step S3, the spatial light modulator in the laser light path is removed, and the precursor film surface is directly irradiated with a single laser pulse without shaping, with a uniform spot, and the energy density is still 0.4 J / cm 2 . All other steps and process parameters are exactly the same as Example 1.

[0057] Comparative Example 4

[0058] This comparative example provides an electrode prepared by a conventional mechanical rolling and coating process. The specific steps are as follows:

[0059] The same electrolytic copper foil substrate as in Example 1 was used. A precision roller with a convex male die engraved with a honeycomb cell diameter (60 pm) and wall width (3 pm) corresponding to that in Example 1 was used to mechanically emboss a 3D storage space and 3D lithium storage carrier space of a honeycomb-shaped pit structure on copper foil, aluminum foil, lithium-aluminum alloy foil, lithium metal foil, etc. The roll forming machine used a double roller structure, the lower roller was a steel roller with a mirror surface polished and plated with hard chromium to increase its surface strength, to ensure that the bottom surface of the metal foil after roll forming had good surface strength and flatness. The upper roller was a convex die with adjustable stroke, and the surface of the roller was a convex hexagonal structure array arranged in a honeycomb structure male die. In order to adapt to the 6-10 pm thick ultra-thin positive electrode aluminum foil current collector, a layer of 0.1-0.2 mm thick stainless steel sheet substrate was placed on the bottom surface of the formed metal foil to prevent wrinkles in the ultra-thin material. After roll forming, a 3-8 pm deep 3D storage space was formed on the surface of the aluminum foil, and a 10-30 pm deep 3D lithium storage carrier space was formed on the surface of the lithium-aluminum alloy foil or lithium metal foil. The depth of the 3D storage space is referenced to the volume deformation of the positive electrode material. The 3D lithium storage carrier is referenced to the volume deformation of the metal negative electrode lithium deposition and stripping, and the stainless steel substrate film is a reusable process material, and the frequency of reuse depends on the requirement of forming accuracy;

[0060] Another silicon-based high-entropy alloy ingot with the same metal components as in step S1 of Example 1 was prepared by arc melting, and was ground into a powder with an average particle size of 5-10 pm by high-energy ball milling;

[0061] The alloy powder prepared in step S2, PVDF binder, and SuperP conductive agent were mixed in a mass ratio of 8:1:1 in NMP solvent to form a slurry, which was uniformly coated on the copper foil with pits in step S1. After vacuum drying and rolling, the electrode of Comparative Example 4 was obtained.

[0062] Comparative Example 5

[0063] Compared with Example 2, the difference is that the precursor target prepared in step S1 does not contain poly(4-vinylphenyl azide) powder. All other steps and process parameters are exactly the same as in Example 2.

[0064] Comparative Example 6

[0065] Compared with Example 3, the difference is that in the laser-induced self-assembly process of step S3, the spatial light modulator in the laser light path is removed, and the unshaped, uniform spot single laser pulse is directly irradiated on the surface of the precursor film, and the energy density is still 0.8 J / cm 2 . All other steps and process parameters are exactly the same as in Example 3.

[0066] Test Example

[0067] Test Example 1: Comparison of structure formation results

[0068] Experimental procedure:

[0069] S1, prepare the electrode samples prepared by Example 1 and Comparative Example 1, Comparative Example 2, Comparative Example 3, Comparative Example 4;

[0070] S2, place each sample in turn on the sample stage of the optical microscope;

[0071] S3, adjust the focal length of the microscope, and observe the surface of each sample under 200 times magnification;

[0072] S4, record the macroscopic morphology characteristics of the surface of each sample under the field of view of the microscope, and arrange them in Table 1 below.

[0073] Table 1: Structure formation results of each sample surface

[0074]

[0075]

[0076] Test result analysis:

[0077] Compare the observation results of Example 1 and Comparative Example 1. In the preparation process of Comparative Example 1, the precursor film does not contain a sacrificial organic component, and the other conditions are the same as Example 1. The experimental results are that the surface material only undergoes local melting and re-solidification, and does not form a three-dimensional structure. This shows that the local high pressure generated by the instantaneous decomposition and gasification of the sacrificial organic component under the action of laser pulses is the necessary condition for the molten metal component to overcome its surface tension, separate from the substrate plane, and reassemble to form a three-dimensional skeleton.

[0078] Compare the observation results of Example 1 and Comparative Example 2 and Comparative Example 3. Comparative Example 2 uses a laser energy density higher than the ablation threshold of the material, resulting in direct gasification and removal of the material, rather than controlled phase separation and reconstruction. In the preparation process of Comparative Example 3, the spatial light modulator is removed, so that the laser energy cannot form a field with a preset pattern and a periodic energy distribution on the surface of the film. Therefore, the molten metal component lacks a driving gradient and spatial constraint for migration from the energy peak area to the energy valley area and orderly aggregation. This shows that accurately controlling the laser energy density within the non-ablation threshold and using a spatial light modulator to shape the energy field are technical prerequisites for realizing orderly self-assembly rather than disordered melting or material ablation.

[0079] Based on the above test results, the technical effect of the method of the present application relies on the synergistic effect of the three technical conditions of the high-entropy metal-organic amorphous precursor thin film, the single ultrafast laser pulse in the specific energy window, and the energy field distribution defined by the spatial light modulator. This mechanism ultimately realizes the direct generation of the honeycomb framework 1 integrated with the substrate on the surface of the electrode current collector substrate 3, which is essentially different from the way of mechanical imprinting by external force and subsequent physical filling of materials in the comparative example 4.

[0080] Test Example 2: Comparison test of electrochemical performance

[0081] Experimental steps:

[0082] S1, the electrode samples prepared by example 1, example 2, example 3 and comparative example 4 were assembled in an argon atmosphere glove box. A circular electrode piece with a diameter of 15 mm was selected as the working electrode (anode), a lithium metal piece was selected as the counter electrode (cathode), and a Li 6.5 La3Zr 1.5 Ta 0.5 O 12 The solid-state electrolyte sheet was placed between the two. The above assembly was packaged in a CR2032 type button cell shell, and an appropriate amount of electrolyte was added to ensure interface wetting. After assembly, the battery was placed at room temperature for 12 hours.

[0083] S2, using an electrochemical workstation, each battery sample after standing was tested under open circuit voltage. The frequency range of the test was set to 1 MHz to 10 mHz, and the amplitude of the applied AC perturbation voltage was 10 mV. The obtained Nyquist plot data was fitted by an equivalent circuit model, and the charge transfer resistance value was extracted.

[0084] S3, using a multi-channel battery test system, each battery sample was tested in a constant temperature environment of 25°C. The test current density was set to 0.2C rate, and the voltage window was set to 0.01V to 1.5V. The discharge specific capacity and charge specific capacity of the first charge-discharge cycle were recorded, and the first coulombic efficiency was calculated. Continuous cycle test was carried out, and the capacity retention rate after 100 cycles was recorded.

[0085] Table 2: Electrochemical performance data of each sample

[0086]

[0087]

[0088] Test result analysis:

[0089] The charge transfer resistance of Example 1, 2, 3 and Comparative Example 4 were compared, and the Rct values of the former three were significantly lower than the latter. This result indicates that the electrode prepared by the method of the present application has a smaller resistance in the interface charge transfer process between the electrode active material and the current collector. This is because in the laser-induced self-assembly process, the molten metal component is directly solidified on the surface of the electrode current collector substrate 3, forming an integrated metallurgical bonding interface without physical gap. This interface provides a continuous conductive path for electron transport, which is different from the high resistance interface formed by physical compaction between the active material powder and the current collector in Comparative Example 4, which is composed of a large number of point contacts.

[0090] The initial coulombic efficiency of Example 1, 2, 3 is higher than that of Comparative Example 4. The initial coulombic efficiency is directly related to the irreversible capacity loss in the initial cycle. The electrode prepared by the method of the present application has an integrated and stable structure between the active material skeleton and the current collector, which ensures that all active materials have good electrochemical contact during the first lithium intercalation process, reducing the irreversible lithium consumption caused by the dead zone formed by the poor contact of part of the active material. At the same time, the non-contact preparation process avoids mechanical damage to the current collector substrate, maintaining its surface integrity.

[0091] In terms of cycle stability, Example 1, 2, 3 all show higher capacity retention rate than Comparative Example 4 after 100 cycles. This is due to the structural characteristics of the three-dimensional honeycomb skeleton 2 formed. This three-dimensional and continuous conductive skeleton provides stable mechanical support and persistent conductive network for the active material, which can effectively buffer the volume change of the active material during repeated charge and discharge process, and inhibit its pulverization and falling off from the current collector. In contrast, the powder electrode structure maintained by the binder in Comparative Example 4 is easy to deteriorate the conductive contact between the particles after experiencing the stress of volume expansion and contraction, leading to the gradual failure of the active material and the rapid decay of the capacity.

[0092] Although embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, replacements and changes can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A solid-state lithium battery electrode, characterized in that, include: Electrode current collector substrate (3); A three-dimensional honeycomb skeleton (2) made of high-entropy alloy is disposed on the surface of the electrode current collector substrate (3); The bottom of the honeycomb skeleton (1) and the surface of the electrode current collector substrate (3) are integrally metallurgically bonded.

2. The solid-state lithium battery electrode according to claim 1, characterized in that, The honeycomb skeleton (1) constitutes a honeycomb cell, the diameter of the honeycomb cell is 20-100μm, and the width of the honeycomb skeleton (1) constituting the honeycomb cell is 1-5μm.

3. The solid-state lithium battery electrode according to claim 1, characterized in that, The high-entropy alloy constituting the honeycomb skeleton (1) contains, by atomic percentage, 50-80 at.% silicon, 10-25 at.% aluminum and 5-15 at.% nickel.

4. The solid-state lithium battery electrode according to claim 1, characterized in that, The electrode current collector substrate (3) is a copper foil or an aluminum foil.

5. A method for preparing a honeycomb biomimetic structure for a solid-state lithium battery electrode according to any one of claims 1-5, characterized in that, Includes the following steps: S1. First, a high-entropy metal-organic amorphous precursor film with a thickness of 5-30 μm is deposited on the electrode current collector substrate (3) using magnetron sputtering. S2. Then, in an inert gas environment, the high-entropy metal-organic amorphous precursor film is irradiated with a laser pulse with a single pulse width of 10-100 ps; wherein, the laser pulse is shaped by a spatial light modulator loaded with a digital hologram, forming an energy density of 0.1-0.8 J / cm² on the surface of the precursor film. 2 The honeycomb grid interference pattern is used to induce phase separation and self-assembly of the precursor film, thereby forming a honeycomb skeleton (1) integrated with the electrode current collector substrate (3); S3. Finally, the electrodes that form the honeycomb skeleton (1) are post-processed.

6. The method for preparing a honeycomb biomimetic structure for a solid-state lithium battery electrode according to claim 1, characterized in that, The high-entropy metal-organic amorphous precursor film in step S1 is composed of a metal component and a sacrificial organic component, wherein the metal component comprises, by atomic percentage, 50-80 at.% silicon, 10-25 at.% aluminum and 5-15 at.% nickel; and the sacrificial organic component accounts for 2-10 vol.% of the total volume of the film.

7. The method for preparing a honeycomb biomimetic structure for a solid-state lithium battery electrode according to claim 5, characterized in that, The process parameters for the magnetron sputtering process in step S1 include: working gas pressure of 0.1-1.0 Pa and sputtering power of 100-500 W.

8. The method for preparing a honeycomb biomimetic structure for a solid-state lithium battery electrode according to claim 5, characterized in that, The digital hologram loaded by the spatial light modulator in step S2 is generated by software based on an iterative Fourier transform algorithm and is used to reconstruct the honeycomb grid interference pattern on the surface of the precursor thin film.

9. The method for preparing a honeycomb biomimetic structure for a solid-state lithium battery electrode according to claim 5, characterized in that, The inert gas environment in step S2 is an argon or nitrogen environment with a pressure of 1.0×10⁵-1.2×10⁵ Pa.

10. The method for preparing a honeycomb biomimetic structure for a solid-state lithium battery electrode according to claim 5, characterized in that, The post-processing in step S3 includes: first, plasma cleaning with a radio frequency power of 20-80W, and then vacuum thermal stabilization treatment with a vacuum degree of not less than 1.0×10-3Pa, an annealing temperature of 150-300℃, and a holding time of 1-4 hours.

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