Electrode with artificial interface protection layer, preparation method thereof and alkali metal battery

Abstract

The invention discloses an electrode with an artificial interface protection layer, a preparation method of the electrode and an alkali metal battery, and relates to the technical field of lithium batteries. The artificial interface protection layer provided by the invention contains alkali metal modified palygorskite (such as Li-Pal) and thermoplastic polyurethane elastomer (TPU) in a specific proportion, and Li-Pal with negative charge on the surface shows excellent Li < + > affinity, so that the concentration gradient of Li < + > can be reduced, and uniform deposition of Li is promoted. The high elasticity of TPU can inhibit the growth and puncture of lithium dendrites in the circulation process, and meanwhile, the structural stability of the protective layer is remarkably enhanced by a hydrogen bond formed between Si-O of Li-Pal and N-H of TPU. The performance of the hybrid layer modified electrode is superior to that of a corresponding bare electrode, the hybrid layer modified electrode has high mechanical stability and lithium (or sodium) dendritic crystal growth inhibition capability, the cycle performance of the battery is favorably improved, and the hybrid layer modified electrode shows good practicability and economic value.

Description

Technical Field

[0001] The present invention relates to the technical field of alkali metal batteries, and more particularly, to an electrode with an artificial interface protection layer, a preparation method thereof, and an alkali metal battery. Background Art

[0002] With the growing demand for high energy density rechargeable batteries, the development of new electrode materials and advanced battery systems is required. Lithium metal has an extremely high specific capacity (3860 mAh g -1 ), and the lowest electrochemical potential (-3.04 V vs. SHE), making it an ideal candidate for the anode of lithium batteries. However, certain challenges caused by the unstable interface between the lithium metal anode and the organic electrolyte have hindered the commercial application of lithium metal batteries. The host-free characteristic of lithium metal usually results in unacceptable volume expansion, further promoting uncontrollable lithium dendrite growth. The rapid growth of lithium dendrites during cycling can pierce the separator, especially under high current density conditions, leading to serious safety hazards. In addition, the severe parasitic reaction between lithium metal and solvent molecules continuously consumes lithium sources and electrolytes, resulting in a low Coulombic efficiency of the battery. Moreover, during the plating / stripping process, the volume change of the lithium anode causes the fragile solid electrolyte interface (SEI) to continuously break and reconstruct, leading to increased polarization and capacity decay of the battery.

[0003] To solve the interface problems of lithium metal anodes, the current main optimization methods include electrolyte optimization and artificial interface engineering strategies. Electrolyte optimization improves the stability and ionic conductivity of the SEI by changing the solvent composition or introducing functional additives that promote Li + diffusion. However, the low Young's modulus of the in-situ formed SEI is insufficient to prevent dendrites from penetrating during repeated cycling. Recently, great interest has been shown in constructing an artificial SEI on the lithium anode by introducing inorganic or organic materials to improve the mechanical strength. For example, Guo et al. reported polyrotaxane-copolyacrylic acid (PRPAA) polymers as an adaptive interface layer, which showed a strong ability to self-heal cracks during cycling. However, this artificial interface layer only "passively" alleviates the battery fluctuations caused by dendrite growth, but lacks the ability to regulate Li + . From the mechanism of Li nucleation and growth, the mass transfer behavior of Li + in the electrolyte has a significant impact on the morphology of Li deposition. The diffusion limitation of Li + induces a large space charge layer and a Li + concentration gradient near the anode surface, which is the main reason for the appearance of lithium dendrites. Dendrites will pierce the uneven and fragile SEI and contact with the electrolyte to further accelerate dendrite growth. Some inorganic materials have been reported to be used to alleviate concentration polarization and promote Li +Fast transportation. However, the interface layer composed of these inorganic components and common PVDF binders exhibits brittleness and will be crushed under stress.

[0004] Therefore, there is an urgent need to develop an artificial interface layer with high mechanical properties and good Li + affinity to inhibit the growth ability of lithium dendrites and thus improve the cycling performance of the battery.

[0005] In view of this, the present invention is specifically proposed. Summary of the Invention

[0006] The purpose of the present invention is to provide an electrode with an artificial interface protection layer, its preparation method and an alkali metal battery, aiming to provide an artificial interface protection layer with high mechanical properties and the ability to inhibit the growth of lithium dendrites to improve the cycling performance of the battery.

[0007] The present invention is implemented as follows: In a first aspect, the present invention provides an electrode with an artificial interface protection layer, including an electrode substrate, on the surface of which an artificial interface protection layer is formed. The artificial interface protection layer includes alkali-metalized palygorskite and thermoplastic polyurethane elastomer, and the mass ratio of alkali-metalized palygorskite to thermoplastic polyurethane elastomer is 1:(5 - 20); Among them, the alkali-metalized palygorskite is obtained by ion exchange of palygorskite with a lithium salt solution or a sodium salt solution.

[0008] In an optional embodiment, the mass ratio of alkali-metalized palygorskite to thermoplastic polyurethane elastomer is 1:(7 - 11).

[0009] In an optional embodiment, the electrode substrate is at least one of metallic lithium, alloy lithium or a negative electrode sheet; Among them, the negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer loaded on the negative electrode current collector, and the negative electrode active material in the negative electrode active material layer is selected from at least one of nano-silicon, micro-silicon, SiO x and silicon-carbon materials; and / or, the thickness of the artificial interface protection layer is 3 μm - 8 μm.

[0010] In a second aspect, the present invention provides a preparation method of an electrode with an artificial interface protection layer according to any one of the foregoing embodiments, including: mixing alkali-metalized palygorskite, thermoplastic polyurethane elastomer and a first solvent to obtain a slurry; Coating the slurry on the electrode substrate and then drying.

[0011] In an optional embodiment, the total weight of alkali-metalized palygorskite and thermoplastic polyurethane elastomer and the mass ratio of the first solvent is (5 - 15):100; And / or, the first solvent is selected from at least one of N-methylpyrrolidone, N,N-dimethylformamide, and dimethyl sulfoxide.

[0012] In an alternative embodiment, the drying temperature is 60°C - 100°C, and the drying time is 10 h - 20 h.

[0013] In an alternative embodiment, the preparation process of the alkali metal-modified palygorskite includes: mixing an alkali metal salt, palygorskite, and water, and stirring for 10 h - 15 h, then performing solid-liquid separation to obtain a solid material, and washing and drying the solid material; Among them, the alkali metal salt is a lithium salt or a sodium salt.

[0014] In an alternative embodiment, the process of drying the solid material includes: first drying at 60°C - 120°C for 8 h - 16 h, and then drying at 180°C - 220°C for 2 h - 4 h.

[0015] In an alternative embodiment, the electrode substrate is at least one of metallic lithium, alloy lithium, and a negative electrode sheet; Among them, the preparation process of the negative electrode sheet includes: mixing a negative electrode active material, a conductive agent, and a binder, and homogenizing to obtain a negative electrode slurry, coating the negative electrode slurry on a negative electrode current collector, and then drying.

[0016] In a third aspect, the present invention provides an alkali metal battery, including an electrode with an artificial interface protection layer in any one of the foregoing embodiments or an electrode with an artificial interface protection layer prepared by the preparation method in any one of the foregoing embodiments, and using the electrode with an artificial interface protection layer as the negative electrode.

[0017] The present invention has the following beneficial effects: The artificial interface protection layer provided by the present invention contains alkali metal-modified palygorskite (such as Li-Pal or Na-Pal) and thermoplastic polyurethane elastomer (TPU) in a specific proportion. Taking Li-Pal as an example, Li-Pal with a negatively charged surface exhibits excellent Li + affinity, which can reduce the Li + concentration gradient and promote the uniform deposition of Li. The high elasticity of TPU can inhibit the growth and piercing of lithium dendrites during cycling. At the same time, the hydrogen bond formed between Si-O of Li-Pal and N-H of TPU significantly enhances the structural stability of the protection layer. The electrode modified by this hybrid layer has better performance than the corresponding bare electrode, has high mechanical stability and the ability to inhibit the growth of lithium (or sodium) dendrites, is beneficial to improving the cycling performance of the battery, and shows good practicability and economic value. Description of the Drawings

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other relevant drawings can also be obtained based on these drawings.

[0019] Figure 1 It is the structural formula of the thermoplastic polyurethane elastomer (TPU) adopted in the embodiments of the present invention; Figure 2 It is the XRD pattern of palygorskite before and after lithiation; Figure 3 It is the high-resolution XPS spectrum of Li-pal: (a) Al 2p, (b) Si 2p, (c) Mg 1s, and (d) Li 1s; Figure 4 It is the FT-IR pattern of pure TPU and the LPT artificial interface protective layer; Figure 5 It is the cyclic stability test result diagram of the LiFePO 4 full battery of bare lithium and LPT@Li electrodes at a 5C rate; Figure 6 It is the cyclic stability test result diagram of the LiFePO 4 full battery of bare lithium and LPT@Li electrodes at a 2C rate; Figure 7 It is the cyclic stability test result diagram of the NCM811 full battery of bare lithium and LPT@Li electrodes at a 0.5C rate; Figure 8 It is the cyclic stability test result diagram of the symmetric batteries of bare lithium and LPT@Li electrodes using an ether-based electrolyte under the conditions of 1 mA cm -2 and 1 mAh cm -2 during constant current charge and discharge cycling life test; Figure 9 It is the cyclic stability test result diagram of the symmetric batteries of bare lithium and LPT@Li electrodes using an ester-based electrolyte under the conditions of 1 mA cm -2 and 1 mAh cm -2 during constant current charge and discharge cycling life test. Detailed Embodiments

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. For those conditions not specified in the embodiments, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. For the reagents or instruments without indicating the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0021] An embodiment of the present invention provides an electrode with an artificial interface protective layer, which includes an electrode substrate, and an artificial interface protective layer is formed on the surface of the electrode substrate. The artificial interface protective layer includes alkali metalized palygorskite and thermoplastic polyurethane elastomer (TPU). The alkali metalized palygorskite is obtained by ion exchange of palygorskite with a lithium salt solution or a sodium salt solution, such as lithiated palygorskite Li-Pal or sodium palygorskite Na-Pal. Hereinafter, Li-Pal will be taken as an example for illustration.

[0022] It should be noted that the present invention integrates materials with excellent mechanical elasticity and high Li + affinity into this artificial SEI at the same time. The LPT layer (formed by Li-Pal and TPU) realizes dendrite-free Li deposition and achieves long-term cycle stability of lithium metal batteries. Specifically, the negatively charged property on the surface of Li-Pal ensures the continuous supply of Li + , thereby weakening the concentration gradient and promoting uniform Li deposition. The highly elastic TPU ensures that the interface layer adapts to volume changes during cycling. The formed LPT layer is proven to solve the interface instability problem of lithium metal anodes, showing good practicality and economic value.

[0023] The thermoplastic polyurethane elastomer (TPU) is a commercially available material, such as it can be purchased from Wanhua Chemical Group Co., Ltd., and its structural formula is as Figure 1 shown, with soft segments and hard segments, and the values of x and y are not limited.

[0024] Furthermore, the mass ratio of the alkali metalized palygorskite to the thermoplastic polyurethane elastomer is 1:(5 - 20), such as 1:5, 1:7, 1:8, 1:9, 1:10, 1:11, 1:13, 1:15, 1:18, 1:20, etc., and preferably 1:(7 - 11). When the mass ratio of the alkali metalized palygorskite to the thermoplastic polyurethane elastomer is within the above range, it can better inhibit the growth of lithium dendrites (or sodium dendrites), which is beneficial to further improving the cycle performance of the battery.

[0025] In some embodiments, the electrode substrate is at least one of metallic lithium, alloy lithium, or a negative electrode sheet. The electrode substrate can be any one or several of the above. Metallic lithium and alloy lithium can be commercially available materials, and the negative electrode sheet can be prepared by conventional methods. For example, the negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer loaded on the negative electrode current collector. The negative electrode active material in the negative electrode active material layer is selected from at least one of nano-silicon, micro-silicon, SiO x and silicon-carbon materials. The negative electrode active material can be any one or several of the above. Specifically, x in SiO x is greater than or equal to 1, and when x = 1, it represents silicon monoxide.

[0026] In some embodiments, the thickness of the artificial interface protective layer is 3 μm - 8 μm, such as 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, etc.

[0027] An embodiment of the present invention provides a method for preparing an electrode with an artificial interface protective layer, and the steps are as follows: S1. Provide alkali metal-modified palygorskite The alkali metal-modified palygorskite can be lithium-modified palygorskite Li-Pal or sodium-modified palygorskite Na-Pal. The preparation process of the alkali metal-modified palygorskite includes: mixing an alkali metal salt, palygorskite and water and stirring for 10 h - 15 h (such as 10 h, 12 h, 15 h, etc.) to complete the ion exchange process, and then separating the solid and liquid to obtain a solid material, washing and drying the solid material to obtain the alkali metal-modified palygorskite. Among them, the alkali metal salt is a lithium salt or a sodium salt, and both the sodium salt and the lithium salt are suitable for the above ion exchange method.

[0028] In some embodiments, solid-liquid separation can be carried out by filtration or other means. The process of drying the obtained solid material includes: first drying at 60°C - 120°C for 8 h - 16 h, and then drying at 180°C - 220°C for 2 h - 4 h to fully remove water through a two-stage drying process. Specifically, the drying temperature of the first stage can be 60°C, 80°C, 100°C, 120°C, etc., and the drying time can be 8 h, 10 h, 12 h, 14 h, 16 h, etc.; the drying temperature of the second stage can be 180°C, 200°C, 220°C, etc., and the drying time can be 2 h, 3 h, 4 h, etc.

[0029] S2. Pulping Mix the alkali metal-modified palygorskite, thermoplastic polyurethane elastomer and a first solvent to obtain a slurry. The type of the first solvent is not limited, such as at least one of N-methylpyrrolidone, N,N-dimethylformamide and dimethyl sulfoxide, and specifically can be any one or several of the above.

[0030] In some embodiments, the mass ratio of the total weight of the alkali metal-modified palygorskite and the thermoplastic polyurethane elastomer to the mass of the first solvent is (5 - 15):100, such as 5:100, 8:100, 10:100, 12:100, 15:100, etc. It is appropriate to use the first solvent within the above range to make the alkali metal-modified palygorskite and the thermoplastic polyurethane elastomer disperse evenly and make it easier to control the coating thickness.

[0031] S3. Coating and drying Coat the slurry obtained in step S2 on the electrode substrate, and then dry it to obtain an electrode with an artificial interface protective layer. The coating thickness is obtained according to the thickness of the artificial interface protective layer to make the thickness of the artificial interface protective layer meet the requirements, such as 3 μm - 8 μm.

[0032] In some embodiments, the drying temperature is 60°C - 100°C and the drying time is 10h - 20h. By regulating the drying temperature and time, the first solvent can be fully removed. Specifically, the drying process can be heating the slurry-coated electrode in an argon glove box. The drying temperature can be 60°C, 80°C, 100°C, etc., and the drying time can be 10h, 12h, 15h, 18h, 20h, etc.

[0033] In some embodiments, the electrode substrate is at least one of metallic lithium, lithium alloy, or the negative electrode sheet. The electrode substrate can be any one or several of the above. Among them, the preparation process of the negative electrode sheet includes: mixing the negative electrode active material, conductive agent, and binder, and homogenizing to obtain a negative electrode slurry, coating the negative electrode slurry on the negative electrode current collector, and then drying. The types and amounts of the conductive agent and binder are not limited. For example, the conductive agent can be conductive carbon black, and the binder can be PVDF (polyvinylidene fluoride).

[0034] An embodiment of the present invention provides an alkali metal battery, including the electrode with an artificial interface protection layer provided by the embodiment of the present invention. Using the electrode with an artificial interface protection layer as the negative electrode, through the improvement of the negative electrode, it has high mechanical stability and the ability to inhibit dendrite growth.

[0035] The alkali metal battery may further include a separator, an electrolyte, and a positive electrode, and the specific types are not limited.

[0036] The features and properties of the present invention will be further described in detail below in conjunction with embodiments.

[0037] Example 1 This embodiment provides a preparation method for an electrode with an artificial interface protection layer, for preparing a lithium electrode modified with an LPT artificial interface protection layer (LPT@Li). The steps are as follows: (1) Add 1 g of lithium chloride (LiCl) and 5 g of Pal to 50 mL of deionized water, mechanically stir at room temperature for 12 h, then filter to obtain a solid material, and wash the solid material with deionized water. Dry the washed sample at 80°C for 12 h, and finally further dry at 200°C for 3 h to obtain Li-Pal.

[0038] (2) Add a total of 0.1 g of Li-Pal and TPU to 1 g of N-methylpyrrolidone (NMP) solvent, and stir for 30 min to obtain a slurry. Among them, the mass ratio of Li-Pal to TPU is 1:9.

[0039] (3) Coat the slurry obtained in step (2) on a clean lithium foil (with a thickness of 500 - 1000 μm), and apply it evenly with a scraper. Then, heat it at 80 °C for 12 h in an argon glove box to obtain a lithium electrode modified with an LPT layer (LPT@Li). The thickness of the artificial interface protection layer measured by SEM is 5 μm.

[0040] Example 2 The preparation method of the lithium electrode modified with the LPT artificial interface protection layer (LPT@Li) refers to Example 1, with the only difference being that the mass ratio of Li-Pal to TPU is 1:19.

[0041] Example 3 The preparation method of the lithium electrode modified with the LPT artificial interface protection layer (LPT@Li) refers to Example 1, with the only difference being that the mass ratio of Li-Pal to TPU is 1:5.67.

[0042] Example 4 The preparation method of the lithium electrode modified with the LPT artificial interface protection layer (LPT@Li) refers to Example 1, with the only difference being that the mass ratio of Li-Pal to TPU is 1:12 Example 5 The preparation method of the lithium electrode modified with the LPT artificial interface protection layer (LPT@Li) refers to Example 1, with the only difference being that the mass ratio of Li-Pal to TPU is 1:15.

[0043] Example 6 The preparation method of the lithium electrode modified with the LPT artificial interface protection layer (LPT@Li) refers to Example 1, with the only difference being that the mass ratio of Li-Pal to TPU is 1:17.

[0044] Comparative Example 1 This comparative example provides a Li electrode without an LPT artificial interface protection layer modification, that is, the clean lithium foil used in Example 1.

[0045] Comparative Example 2 The difference from Example 1 is only that TPU is not introduced, that is, TPU in step (2) is replaced with an equal amount of Li-Pal.

[0046] Comparative Example 3 The difference from Example 1 is only that Li-Pal is not introduced, that is, Li-Pal in step (2) is replaced with an equal amount of TPU.

[0047] Comparative Example 4 The difference from Example 1 is only that TPU is replaced with an equal amount of polyvinylidene fluoride (PVDF).

[0048] Test Example 1 XRD patterns of palygorskite before and after lithiation in Test Example 1 are shown as Figure 2 follows. It can be seen that the XRD patterns of the two are consistent with the standard pattern (PDF#29 - 0855), proving that lithiation has not changed the structure of palygorskite.

[0049] High - resolution XPS pattern of lithiated palygorskite in Test Example 1 is shown as Figure 3 follows. It can be seen that the Li 1s spectrum can be fitted to a peak with a binding energy of 57.4 eV, corresponding to the characteristic peak of Li + , proving the existence of lithium ions in lithiated palygorskite.

[0050] FT - IR patterns of pure TPU and LPT artificial interface protective layers in Test Example 1 are shown as Figure 4 follows. It can be seen that N - H is redshifted from 3326 cm -1 to 3322 cm -1 , which is due to the formation of hydrogen bonds between TPU and Li - Pal, further improving the mechanical strength.

[0051] Test Example 2 The electrodes of the examples and comparative examples were used to prepare lithium - metal batteries and relevant tests were carried out. The specific steps are as follows: (1) The positive - electrode active material lithium nickel cobalt manganese oxide LiNi 0.8 Co 0.1 Mn 0.1 O 2 or lithium iron phosphate, conductive agent carbon black, and binder polyvinylidene fluoride were mixed in a weight ratio of 8:1:1 to form a positive - electrode slurry, which was coated on the positive - electrode current collector Al foil. After drying and rolling, the positive - electrode plate was obtained.

[0052] (2) Under an argon - protected atmosphere with an oxygen content and a water content both less than 1 ppm, 1 M LiPF 6 was dissolved in a mixed solution of ethylene carbonate and diethyl carbonate with a volume ratio of 1:1 to obtain a homogeneous organic - ester electrolyte; 1 M LiTFSI was dissolved in a mixed solution of dioxolane and dimethoxyethane with a volume ratio of 1:1, and 1 wt% LiNO 3 was added thereto to obtain a homogeneous organic - ether electrolyte.

[0053] (3) Coin - type battery assembly was carried out in a glove box with a water and oxygen content both less than 1 ppm. The battery - case model was 2025 - type battery case; the ester - type electrolyte prepared in step (2) was dropped onto the surface of the separator, and the positive - electrode battery case, positive - electrode plate, separator, negative - electrode plate, and negative - electrode battery case were stacked in sequence and sealed.

[0054] (4)Charge and discharge cycle performance test: Using the electrode sheets of the examples and comparative examples as the negative electrode sheets, and the lithium iron phosphate electrode sheet as the positive electrode sheet to assemble full cells (LPT@Li||LFP, Li||LFP), respectively, at 2C (LFP active material loading 9.8 mg cm -2 ), and 5C (LFP active material loading 3.6 mg cm -2 ), the charge and discharge cycle performance test was carried out at a charge and discharge cut-off voltage of 2.5 - 4V; Using the electrode sheets of the examples and comparative examples as the negative electrode sheets, and the LiNi 0.8 Co 0.1 Mn 0.1 O 2 electrode sheet as the positive electrode sheet to assemble full cells (LPT@Li||NCM811, Li||NCM811, active material loading 3.6 mg cm -2 ), and the charge and discharge cycle performance test was carried out at a charge and discharge cut-off voltage of 2.7 - 4.3V at a rate of 0.5C.

[0055] Using the pole pieces prepared in Examples 1 - 3 and the ether-based electrolyte and ester-based electrolyte prepared in step (2) to assemble Li||Li symmetric cells, and the constant current charge and discharge test cycle life was carried out under the conditions of 1 mA cm -2 and 1 mAh cm -2 .

[0056] The cycle performance test results of the examples and comparative examples are shown in Table 1 and Figures 4 - 9 : Table 1 Cycle performance test results of examples and comparative examples

[0057] By comparing Examples 1 - 3 and the comparative examples, it can be seen that the LPT artificial interface protective layer selected in the present invention has high mechanical strength and good Li + affinity, and significantly inhibits the growth of lithium dendrites. Compared with bare lithium, the full cells assembled with LiFePO 4 and LiNi 0.8 Mn 0.1 Co 0.1 O 2 and the LPT@Li electrode provide excellent life in long-term and high-current cycles. And it is found that the LPT layer obtained when the mass ratio of Li-Pal to TPU is 1:9 has the best effect, showing good practicability and economic benefits.

[0058] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An electrode having an artificial interface protective layer, characterized in that: It comprises an electrode substrate, an artificial interface protection layer is formed on the surface of the electrode substrate, the artificial interface protection layer comprises alkali metal palygorskite and thermoplastic polyurethane elastomer, and the mass ratio of alkali metal palygorskite to thermoplastic polyurethane elastomer is 1:(5-20); The alkali metalized palygorskite is obtained by ion exchange between a lithium salt solution or a sodium salt solution and palygorskite.

2. The electrode with an artificial interface protective layer according to claim 1, characterized in that: The mass ratio of alkali metalized palygorskite to thermoplastic polyurethane elastomer is 1:(7-11).

3. The electrode with an artificial interface protective layer according to claim 1 or 2, characterized in that: The electrode substrate is at least one of metallic lithium, alloy lithium or a negative electrode plate; The negative electrode sheet comprises a negative electrode current collector and a negative electrode active material layer loaded on the negative electrode current collector, and the negative electrode active material in the negative electrode active material layer is selected from nano silicon, micro silicon, SiO x and at least one of a silicon-carbon material; And / or, the thickness of the artificial interface protection layer is 3 μm-8 μm.

4. A method for preparing an electrode having an artificial interface protective layer according to any one of claims 1 to 3, characterized in that: include: mixing alkali metallized palygorskite, thermoplastic polyurethane elastomer and a first solvent to obtain a slurry; The slurry is coated on an electrode substrate and then dried.

5. The preparation method according to claim 4, characterized in that: The mass ratio of the total weight of the alkali metal palygorskite and the thermoplastic polyurethane elastomer to the first solvent is (5-15): 100; And / or, the first solvent is selected from at least one of N-methylpyrrolidone, N,N-dimethylformamide and dimethyl sulfoxide.

6. The preparation method according to claim 4, characterized in that: The drying temperature is 60℃-100℃, and the drying time is 10h-20h.

7. The preparation method according to claim 4, characterized in that: The preparation process of the alkali metal palygorskite comprises: mixing and stirring an alkali metal salt, palygorskite and water for 10 hours to 15 hours, then separating the solid and liquid to obtain a solid material, and washing and drying the solid material; Wherein, the alkali metal salt is a lithium salt or a sodium salt.

8. The preparation method according to claim 7, characterized in that: The process of drying the solid material includes: first drying at 60° C.-120° C. for 8 h-16 h, and then drying at 180° C.-220° C. for 2 h-4 h.

9. The preparation method according to claim 4, characterized in that: The electrode substrate is at least one of metallic lithium, alloy lithium or a negative electrode plate; The preparation process of the negative electrode sheet includes: mixing and homogenizing the negative electrode active material, the conductive agent and the binder to obtain the negative electrode slurry, coating the negative electrode slurry on the negative electrode current collector, and then drying.

10. An alkali metal battery, characterized in that: The invention comprises the electrode with an artificial interface protection layer as described in any one of claims 1 to 3 or the electrode with an artificial interface protection layer prepared by the preparation method as described in any one of claims 4 to 9, wherein the electrode with an artificial interface protection layer is used as a negative electrode.

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