Composite multifunctional lithium metal anode and preparation method and application thereof

Abstract

The application discloses a kind of composite multifunctional lithium metal negative and its preparation method and application, it is related to lithium ion battery technical field.The preparation method of a kind of composite multifunctional lithium metal negative includes the following steps: lithiumophilic nanoparticle is added to N-methyl pyrrolidone solution, is fully dispersed and is coated on copper foil dry, obtain lithiumophilic nanoparticle layer;Lithium negative electrode surface is cleaned and preheating treatment;Lithiumophilic nanoparticle layer is transferred to lithium foil;Lithium foil is evaporated, and thin film is deposited on the surface of lithium foil base bed;Lithium foil after evaporation is cooled and solidified, and composite multifunctional lithium metal negative is obtained.The application solves the problem that lithium deposition is not uniform, causes dendrite growth, interface side reaction triggers irreversible loss, the structure performance of existing SEI layer is insufficient and material interface bonding force is weak.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery technology, specifically to a composite multifunctional lithium metal anode, its preparation method, and its application. Background Technology

[0002] In the ongoing exploration of high-energy-density batteries, lithium metal anodes are considered one of the key materials due to their theoretical specific capacity of up to 3860 mAh / g and low electrochemical potential (-3.04 V vs. standard hydrogen electrode), which is of great significance for driving innovation in battery technology. However, despite the enormous application potential shown by lithium metal anodes, their practical application still faces a series of complex and urgent challenges.

[0003] First, the non-uniform deposition of lithium metal during charge-discharge cycles leads to the formation of lithium dendrites, posing a significant safety hazard. Dendrite growth not only reduces the utilization of effective lithium but can also penetrate the battery separator, causing internal short circuits and potentially triggering thermal runaway, severely threatening battery safety. Second, the interfacial stability between lithium metal and the electrolyte cannot be ignored. During electrochemical reactions, the lithium metal anode is highly susceptible to side reactions in the electrolyte, resulting in an unstable solid electrolyte interphase (SEI) layer. Its uneven thickness, brittleness, and low ionic conductivity lead to continuous loss of active lithium and reduced coulombic efficiency. Repeated breakage and reconstruction of the SEI layer exacerbate battery performance degradation. Furthermore, current technologies have limitations in constructing an ideal SEI layer, making it difficult to balance the requirements of stability and high conductivity. This limits the long-term cycling performance of the lithium metal anode, significantly impacting the overall energy density and cycle life of the battery. In addition, material deposition and transfer techniques are also a current research bottleneck. Traditional methods struggle to ensure the uniformity and stability of the coating, resulting in insufficient interfacial adhesion. Material shedding during cycling becomes commonplace, further deteriorating battery performance.

[0004] In summary, current technologies still face numerous challenges in improving the stability and safety of lithium metal anodes. To achieve the safe and efficient application of lithium metal anodes in high-energy-density batteries, it is urgent to develop new material design strategies and advanced surface treatment technologies to optimize the structure and performance of the SEI layer, suppress dendrite growth, and enhance interface stability, thereby improving battery cycle life and safety. Summary of the Invention

[0005] The technical problem to be solved by this invention is that the existing lithium metal anode has poor stability and safety, and also suffers from problems such as uneven lithium deposition leading to dendrite growth, irreversible losses caused by interfacial side reactions, insufficient structural performance of the existing SEI layer, and weak material interfacial bonding. The purpose is to provide a composite multifunctional lithium metal anode, its preparation method, and its application, which solves the problems of uneven lithium deposition leading to dendrite growth, irreversible losses caused by interfacial side reactions, insufficient structural performance of the existing SEI layer, and weak material interfacial bonding.

[0006] This invention is achieved through the following technical solution:

[0007] In a first aspect, the present invention provides a method for preparing a composite multifunctional lithium metal anode, comprising the following steps:

[0008] Lithophilic nanoparticles were added to an N-methylpyrrolidone solution, dispersed thoroughly, coated onto a copper foil, and dried to obtain a layer of lithiumophilic nanoparticles.

[0009] The surface of the lithium anode is cleaned and preheated.

[0010] Transferring a layer of lithium-loving nanoparticles onto a lithium foil;

[0011] A thin film is deposited on the surface of a lithium foil substrate by vapor deposition.

[0012] The evaporated lithium foil is cooled and solidified to obtain a composite multifunctional lithium metal anode.

[0013] As one possible design, the above-mentioned thorough dispersion involves adding the lithium-loving nanoparticles to an N-methylpyrrolidone solution and magnetically stirring for 4-6 hours.

[0014] As one possible design, the drying process specifically involves vacuum drying the solution of lithium-philic nanoparticles coated on copper foil at 60-70°C for 12-16 hours.

[0015] As one possible design, the above-mentioned transfer of the lithium-loving nanoparticle layer onto the lithium foil specifically involves covering the lithium foil with copper foil, so that the lithium-loving nanoparticle layer is in contact with the lithium foil, pressing a weight onto the copper foil, and after standing for 10-30 minutes, peeling off the copper foil, thus transferring the lithium-loving nanoparticle layer onto the lithium foil.

[0016] As one possible design, the above-mentioned evaporation deposition of lithium foil includes:

[0017] A high ionic conductivity material is heated and evaporated, and a lithium foil is placed on top of the high ionic conductivity material for a single vapor deposition, thereby depositing a thin film on the surface of the lithium foil substrate.

[0018] The inorganic composite material is heated and evaporated, and the evaporated lithium foil is placed on top of the inorganic composite material for a second evaporation, thus depositing a secondary thin film on the surface of the lithium foil substrate.

[0019] As one possible design, the heating and evaporation parameters for the aforementioned high ionic conductivity material are as follows: vacuum degree of 10. -4 -10 -6 Pa, heating power is 230-270W, evaporation rate is

[0020] As one possible design, the aforementioned inorganic composite material is made by fully mixing a variety of inorganic materials, including LiF, Li2O, Li2CO3, Li3N and Li2S.

[0021] As one possible design, the heating and evaporation parameters for the aforementioned inorganic composite material are as follows: vacuum degree is 10. -4 -10 - 6 Pa, heating power is 230-270W, evaporation rate is

[0022] Secondly, the present invention provides a composite multifunctional lithium metal anode, which is prepared by any of the methods described above.

[0023] Thirdly, the present invention provides the application of a composite multifunctional lithium metal anode prepared by the above-mentioned preparation method in battery materials.

[0024] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0025] This invention introduces a layer of lithium-loving nanoparticles, which are then attached to the surface of the lithium anode to reduce the nucleation overpotential and regulate the lithium deposition morphology. Further evaporation then forms a homogeneous lithium-conducting layer, improving Li migration efficiency. Finally, by evaporating lithium foil using high ionic conductivity materials and inorganic composite materials, a multifunctional artificial SEI layer is constructed, enhancing its adhesion to the lithium anode. This significantly improves the stability of the lithium metal anode, reduces capacity decay, extends battery life, and enhances the ionic conductivity, stability, and mechanical properties of the anode material. Simultaneously, by reducing dendrite growth and side reactions, the potential risks of thermal runaway and short circuits are reduced, improving the overall safety performance of the battery. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0027] Figure 1This is a flowchart of the preparation method of the present invention;

[0028] Figure 2 This is a schematic diagram of the preparation method of the present invention;

[0029] Figure 3 The ohmic resistance diagram for Experimental Example 1 of the present invention;

[0030] Figure 4 This is the interface impedance diagram for Experimental Example 1 of the present invention. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments and accompanying drawings. The illustrative embodiments and descriptions of this invention are for explanation only and are not intended to limit the invention. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0032] Existing lithium metal anodes suffer from poor stability and safety, and also suffer from problems such as uneven lithium deposition leading to dendrite growth, irreversible losses caused by interfacial side reactions, insufficient structural performance of existing SEI layers, and weak interfacial bonding. This invention provides a method for preparing a composite multifunctional lithium metal anode. By introducing a lithiophilic layer, the nucleation overpotential is reduced, and the lithium deposition morphology is adjusted. Further evaporation forms a homogeneous lithium-conducting layer, improving Li migration efficiency. Finally, an inorganic composite material is used to construct a multifunctional artificial SEI layer. This method effectively improves ionic conductivity, stability, and mechanical properties, while solving problems such as dendrite growth and poor safety.

[0033] A method for preparing a composite multifunctional lithium metal anode, referring to... Figure 1-2 It includes the following steps:

[0034] S1. Lithophile nanoparticles are added to an N-methylpyrrolidone (NMP) solution, fully dispersed, coated onto a copper foil, and dried to obtain a layer of lithiumophile nanoparticles.

[0035] By coating lithium-loving nanoparticles onto copper foil, the good chemical stability of copper foil and its resistance to adhesion to lithium metal ensure that no copper foil impurities remain during the subsequent separation of the lithium-loving nanoparticle layer.

[0036] By attaching lithiophilic nanoparticles to the surface of a lithium anode, a lithiophilic nanoparticle layer is formed. This lithiophilic layer reduces the potential barrier required for lithium metal nucleation by providing active sites and enhancing interfacial affinity; it can optimize the surface structure of the material, thereby improving lithium-ion diffusion and reducing local supersaturation; at the same time, the lithiophilic layer helps to form a stable deposition substrate, prevents dendrite growth, and ensures smooth and uniform lithium metal deposition, thus improving battery safety and cycle life.

[0037] Preferably, the aforementioned lithium-loving nanoparticles include, but are not limited to, elemental particles and oxides. Elemental particles include Ag, Zn, Al, Ni, and Se, while oxides include CeO2, TiO2, and ZnO.

[0038] In some embodiments of the present invention, the above-mentioned sufficient dispersion is achieved by adding the lithium-philic nanoparticles to an N-methylpyrrolidone (NMP) solution and stirring magnetically for 4-6 hours.

[0039] In some embodiments of the present invention, the drying process specifically involves vacuum drying the solution of lithium-philic nanoparticles coated on copper foil at 60-70°C for 12-16 hours. Preferably, the temperature is 65°C and the vacuum drying time is 14 hours.

[0040] S2. Clean and preheat the surface of the lithium anode.

[0041] By cleaning and preheating the negative electrode surface, the adhesion and uniformity of subsequent evaporation can be ensured.

[0042] S3. Transfer the lithiophilic nanoparticle layer onto the lithium foil.

[0043] By transferring a lithiophilic nanoparticle layer onto a lithium foil, lithium-ion deposition is uniformly guided, reducing irregular lithium growth and fundamentally inhibiting dendrite formation, thus lowering the risk of short circuits caused by dendrites piercing the separator. On one hand, it provides uniform nucleation sites: the surface of the lithiophilic nanoparticle layer has abundant active sites, which can significantly reduce the energy barrier for lithium metal nucleation, promoting lithium-ion deposition on uniformly distributed sites and avoiding dendrite growth caused by local oversaturation. On the other hand, it improves ion conduction pathways: the lithiophilic layer has high lithium-ion conductivity, which can reduce interfacial impedance and optimize lithium-ion migration pathways, thereby promoting uniform lithium deposition at the interface.

[0044] In some embodiments of the present invention, the above-mentioned transfer of the lithium-loving nanoparticle layer onto the lithium foil specifically involves covering the lithium foil with a copper foil so that the lithium-loving nanoparticle layer is in contact with the lithium foil, pressing a weight onto the copper foil, and after standing for 10-30 minutes, peeling off the copper foil. At this point, the lithium-loving nanoparticle layer is transferred onto the lithium foil.

[0045] Because lithium foil has excellent ductility and adhesion to the lithium-loving nanoparticle layer, the lithium-loving nanoparticle layer can be peeled off from the copper foil.

[0046] Preferably, the aforementioned weight can be a 1.5 kg metal disc.

[0047] S4. Evaporate the lithium foil to deposit a thin film (lithium-conducting homogeneous layer) on the surface of the lithium foil substrate.

[0048] The high density of inorganic materials allows them to form a dense protective barrier on the surface of the lithium metal anode, effectively isolating the lithium metal from direct contact with the electrolyte and preventing the decomposition of the electrolyte to produce gases or unstable byproducts, thus significantly reducing the occurrence of side reactions. First, by vapor-depositing a material with high ionic conductivity, the artificial SEI layer is ensured to possess excellent lithium-ion conductivity. Subsequently, a composite inorganic material is vapor-deposited. This material, composed of substances with high chemical stability, high mechanical properties, and high ionic conductivity, endows the SEI layer with multifunctionality. The composite vapor deposition of multiple inorganic materials can form grain boundaries, and the presence of grain boundaries provides a rapid channel for lithium-ion migration, further improving the conductivity of lithium ions and thus optimizing the electrode interface performance. It also effectively isolates the lithium metal anode from direct contact with the electrolyte, significantly reducing the occurrence of side reactions, thereby improving the coulombic efficiency and reversibility of the battery.

[0049] Furthermore, through an optimized material evaporation process, a structurally stable and uniformly thick SEI layer was obtained, which not only improved ionic conductivity but also reduced interfacial impedance, ensuring excellent performance under long-term cycling. In addition, the composite inorganic material layer, being a combination of multiple materials, generates grain boundaries, further increasing the conductivity of lithium ions.

[0050] In some embodiments of the present invention, S4 above includes the following steps:

[0051] S41. The high ionic conductivity material is heated and evaporated, and the lithium foil is placed on top of the high ionic conductivity material for a first evaporation deposition to form a thin film on the surface of the lithium foil substrate.

[0052] In some embodiments of the present invention, the heating and evaporation parameters of the above-mentioned high ionic conductivity material are as follows: vacuum degree is 10. -4 -10 -6 Pa, heating power is 230-270W, evaporation rate is Preferably, the vacuum degree is 10. - 5 Pa, heating power preferably 250W, evaporation rate preferably

[0053] The lithium foil was placed 20-30 cm above the material with high ionic conductivity.

[0054] S42. The inorganic composite material is heated and evaporated, and the evaporated lithium foil is placed on top of the inorganic composite material for a second evaporation, thus depositing a secondary thin film on the surface of the lithium foil substrate.

[0055] In some embodiments of the present invention, the above-mentioned inorganic composite material is made by thoroughly mixing multiple inorganic materials. The inorganic materials include LiF, Li₂O, Li₂CO₃, Li₃N, and Li₂S. Preferably, the above-mentioned inorganic composite material is made by thoroughly mixing three inorganic materials. The ionic conductivity material is preferably a material with a low Li migration barrier, such as Li₃N (Li migration barrier of 0.13 eV) or LiF (Li migration barrier of 0.17 eV).

[0056] In some embodiments of the present invention, the heating and evaporation parameters of the above-mentioned inorganic composite material are as follows: vacuum degree is 10. -4 -10 -6 Pa, heating power is 230-270W, evaporation rate is Preferably, the vacuum degree is 10. -5 Pa, heating power preferably 250W, evaporation rate preferably

[0057] The lithium foil was placed 20-30 cm above the inorganic composite material.

[0058] S5. Cool and solidify the lithium foil after secondary evaporation to obtain a composite multifunctional lithium metal anode.

[0059] After the film is formed, cooling and solidification can firmly bond the evaporated inorganic composite SEI material to the substrate.

[0060] This invention provides a composite multifunctional lithium metal anode, which is prepared by any of the methods described above.

[0061] The present invention also provides the application of a composite multifunctional lithium metal anode prepared by any of the above methods in battery materials.

[0062] Example 1

[0063] S1. First, add the lithium-loving Ag nanoparticles to the NMP solution and stir magnetically for about 5 hours to ensure sufficient dispersion. Then, use a coating rod to uniformly coat the dispersion onto a copper foil and vacuum dry at 65°C for 14 hours to prepare a lithium-loving Ag nanoparticle layer.

[0064] S2. First, prepare a vacuum environment to ensure that evaporation is carried out in an oxygen-free or extremely low-oxygen environment; then clean and preheat the negative electrode surface to ensure the adhesion and uniformity of evaporation.

[0065] S3. Cover the Lithophile Ag nanoparticle layer onto the Li foil and place a 1.5 kg metal disk on top of it. After standing for 20 minutes, take advantage of the ductility of the Li foil and its adhesion to the Lithophile nanoparticles to allow the nanoparticles to adhere to the Li foil. Then, peel the Cu foil off the Li foil, and the nanoparticle layer will naturally transfer to the surface of the Li foil.

[0066] S4. The lithium foil is vapor-deposited to form a thin film on the surface of the lithium foil substrate:

[0067] S41. The substrate with transferred nanoparticles is fixed 25 cm above the crucible. Li3N is added to the crucible in the vacuum chamber. The temperature of the heating source and the evaporation rate are controlled to allow the material to sublimate and deposit on the substrate surface to form a thin film. The vacuum environment is 10°C. -5 Pa, the heating power of the crucible is 250W, and the evaporation rate is

[0068] S42. Thoroughly mix the inorganic components (LiF:Li₂O:Li₂CO₃) in a ratio of 1:1:1 to form a composite inorganic material, and add it to a crucible within a vacuum chamber. Fix the substrate 25 cm above the crucible, control the temperature of the heating source and the evaporation rate to allow the material to sublimate and deposit a thin film on the substrate surface; the vacuum environment is 10... -5 Pa, the heating power of the crucible is 250W, and the evaporation rate is

[0069] S5. After the thin film is formed, it is cooled and solidified to firmly bond the evaporated inorganic composite SEI material with the lithium substrate, thus obtaining a composite multifunctional lithium metal anode.

[0070] Example 2

[0071] This embodiment is basically the same as that of Embodiment 1, except that the lithium-loving nanoparticles are Zn.

[0072] Example 3

[0073] This embodiment is basically the same as that in Embodiment 1, except that the lithium-loving nanoparticles are Se.

[0074] Example 4

[0075] This embodiment is basically the same as Example 1, except that the lithium-loving nanoparticles are ZnO.

[0076] Example 5

[0077] This embodiment is basically the same as Embodiment 1, except that the inorganic components and their ratio are LiF:Li2O:Li3N = 1:1:1.

[0078] Example 6

[0079] This embodiment is basically the same as Embodiment 1, except that the inorganic components and their ratio are LiF:Li2O:Li2S=1:1:1.

[0080] Example 7

[0081] S1. First, the lithiophilic TiO2 nanoparticles were added to an NMP solution and magnetically stirred for about 4 hours to ensure full dispersion. Then, the dispersion was uniformly coated onto a copper foil using a coating rod and vacuum dried at 60°C for 12 hours to prepare a lithiophilic TiO2 nanoparticle layer.

[0082] S2. First, prepare a vacuum environment to ensure that evaporation is carried out in an oxygen-free or extremely low-oxygen environment; then clean and preheat the negative electrode surface to ensure the adhesion and uniformity of evaporation.

[0083] S3. Cover the Lithophile TiO2 nanoparticle layer onto the Li foil and place a 2kg metal disk on it. After standing for 10 minutes, take advantage of the Li foil's ductility and its adhesion to the Lithophile nanoparticles to allow the nanoparticles to adhere to the Li foil. Then, peel the Cu foil off the Li foil, and the nanoparticle layer will naturally transfer to the Li foil surface.

[0084] S4. The lithium foil is vapor-deposited to form a thin film on the surface of the lithium foil substrate:

[0085] S41. The substrate with transferred nanoparticles is fixed 20 cm above the crucible. Li3N is added to the crucible in the vacuum chamber. The temperature of the heating source and the evaporation rate are controlled to allow the material to sublimate and deposit on the substrate surface to form a thin film. The vacuum environment is 10°C. -4 Pa, the heating power of the crucible is 230W, and the evaporation rate is

[0086] S42. Thoroughly mix the inorganic components (LiF:Li₂O:Li₂CO₃) in a ratio of 1:1:1 to form a composite inorganic material, and add it to a crucible in a vacuum chamber. Fix the substrate 20 cm above the crucible, control the temperature of the heating source and the evaporation rate to allow the material to sublimate and deposit a thin film on the substrate surface; the vacuum environment is 10... -4 Pa, the heating power of the crucible is 230W, and the evaporation rate is

[0087] S5. After the thin film is formed, it is cooled and solidified to firmly bond the evaporated inorganic composite SEI material with the lithium substrate, thus obtaining a composite multifunctional lithium metal anode.

[0088] Example 8

[0089] S1. First, the lithium-loving CeO2 nanoparticles were added to an NMP solution and magnetically stirred for about 4 hours to ensure full dispersion. Then, the dispersion was uniformly coated onto a copper foil using a coating rod and vacuum dried at 70°C for 16 hours to prepare a lithium-loving CeO2 nanoparticle layer.

[0090] S2. First, prepare a vacuum environment to ensure that evaporation is carried out in an oxygen-free or extremely low-oxygen environment; then clean and preheat the negative electrode surface to ensure the adhesion and uniformity of evaporation.

[0091] S3. Cover the Lithophile CeO2 nanoparticle layer onto the Li foil and place a 2kg metal disk on top of it. After standing for 30 minutes, take advantage of the Li foil's ductility and its adhesion to the Lithophile nanoparticles to allow the nanoparticles to adhere to the Li foil. Then, peel the Cu foil off the Li foil, and the nanoparticle layer will naturally transfer to the Li foil surface.

[0092] S4. The lithium foil is vapor-deposited to form a thin film on the surface of the lithium foil substrate:

[0093] S41. The substrate with transferred nanoparticles is fixed 30 cm above the crucible. Li3N is added to the crucible in the vacuum chamber. The temperature of the heating source and the evaporation rate are controlled to allow the material to sublimate and deposit on the substrate surface to form a thin film. The vacuum environment is 10°C. -6 Pa, the heating power of the crucible is 270W, and the evaporation rate is

[0094] S42. Thoroughly mix the inorganic components (LiF:Li₂O:Li₂CO₃) in a ratio of 1:1:1 to form a composite inorganic material, and add it to a crucible within a vacuum chamber. Fix the substrate 30 cm above the crucible, control the temperature of the heating source and the evaporation rate to allow the material to sublimate and deposit a thin film on the substrate surface; the vacuum environment is 10... -6 Pa, the heating power of the crucible is 270W, and the evaporation rate is

[0095] S5. After the thin film is formed, it is cooled and solidified to firmly bond the evaporated inorganic composite SEI material with the lithium substrate, thus obtaining a composite multifunctional lithium metal anode.

[0096] Comparative Example 1

[0097] This comparative example is basically the same as Example 1, except that: lithium-loving nanoparticles are not used, steps S1-S3 are not performed, and in step S42, composite inorganic materials are not used, but are replaced with single LiF.

[0098] Comparative Example 2

[0099] This comparative example is basically the same as Example 1, except that: lithium-loving nanoparticles are not used, steps S1-S3 are not performed, and in step S42, composite inorganic materials are not used, but are replaced with single Li3N.

[0100] Comparative Example 3

[0101] This comparative example is basically the same as Example 1, except that: lithium-loving nanoparticles are not used, steps S1-S3 are not performed, and in step S42, composite inorganic materials are not used, but are replaced by single Li2O.

[0102] Comparative Example 4

[0103] This comparative example is basically the same as Example 1, except that lithium-loving nanoparticles are not used.

[0104] Experimental Example 1

[0105] The composite multifunctional lithium metal anodes prepared in Examples 1-6 and Comparative Examples 1-4 were subjected to performance tests, and the capacity retention data after 500 cycles were obtained. The results are shown in Table 1; the ohmic internal resistance data are shown in Table 1. Figure 3 As shown; the interface impedance data results are as follows. Figure 4 As shown.

[0106] Performance testing: In the button cell test, the negative electrode used was a lithium negative electrode prepared in the examples or comparative examples, and the positive electrode had a diameter of 12 mm and an average load of approximately 2 mg cm⁻¹. -2 The battery uses a lithium iron phosphate (LiFePO4) electrode and a polypropylene (PP) separator. It was assembled in an argon-filled glove box using a carbonate-based electrolyte (1.0 mol / L). -1 LiPF6, with ethyl carbonate (EC) and diethyl carbonate (DEC) in a 1:1 volume ratio as solvents. Charge-discharge testing was performed using a battery cycler, first with three activation cycles at 0.2C, followed by 1C (170 mAg) within a 2.5–4.2V voltage window. -1 Rate testing was performed with a fixed charge-discharge time of 1 hour per cycle. Electrochemical impedance spectroscopy (EIS) measurements were conducted using an electrochemical workstation, with a frequency range of 10 Hz. 6 Up to 0.01Hz, the AC disturbance voltage amplitude is 5mV.

[0107] Table 1

[0108]

[0109]

[0110] As can be seen from the data in Table 1, the lithium anode prepared in the embodiments of the present invention retains more than 85% of its capacity after 500 cycles, exhibiting excellent cycle performance. In contrast, the capacity retention of the comparative examples after 500 cycles is significantly lower than that of the embodiments of the present invention. This demonstrates that the present invention can improve the cycle performance, safety, and overall efficiency of lithium batteries. Example 1 shows the highest capacity retention. Comparing Examples 1-4, the highest capacity retention is achieved when the lithiophilic nanoparticles are Ag. Comparing Examples 1 and Examples 5-6, the highest capacity retention is achieved when the inorganic components are LiF, Li₂O, and Li₂CO₃. Comparing Example 1 and Comparative Examples 1-3, it can be seen that using only a single inorganic component or omitting lithiophilic nanoparticles leads to a significant decrease in capacity retention.

[0111] observe Figure 3-4 After 200 cycles, the ohmic internal resistance and interfacial impedance of the embodiment were significantly lower than those of the comparative example, indicating superior electrochemical stability and interfacial compatibility during long-term cycling. The lower ohmic internal resistance reflects more efficient ion and electron transport within the battery, while the lower interfacial impedance indicates fewer interfacial reactions between the lithium anode and the electrolyte, effectively suppressing side reactions. Overall, the embodiment, through optimized design, significantly improved the battery's cycle performance and energy conversion efficiency, demonstrating superior long-term operational capability.

[0112] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a composite multifunctional lithium metal anode, characterized in that, Includes the following steps: Lithophilic nanoparticles were added to an N-methylpyrrolidone solution, dispersed thoroughly, coated onto a copper foil, and dried to obtain a layer of lithiumophilic nanoparticles. The surface of the lithium anode is cleaned and preheated. Transferring a layer of lithium-loving nanoparticles onto a lithium foil; The lithium foil is vapor-deposited by heating and evaporating a high ionic conductivity material, and then placing the lithium foil on top of the high ionic conductivity material for a single vapor deposition to form a thin film on the surface of the lithium foil substrate. The inorganic composite material is heated and evaporated, and the evaporated lithium foil is placed on top of the inorganic composite material for a second evaporation deposition, forming a secondary thin film on the surface of the lithium foil substrate. The inorganic composite material is made by fully mixing various inorganic materials, including LiF, Li2O, Li2CO3, Li3N, and Li2S. The heating and evaporation parameters of the inorganic composite material are as follows: vacuum degree is 10. -4 -10 -6 Pa, heating power of 230-270W, evaporation rate of 3.5-7.5 Å / s; The evaporated lithium foil is cooled and solidified to obtain a composite multifunctional lithium metal anode.

2. The method for preparing a composite multifunctional lithium metal anode according to claim 1, characterized in that, The thorough dispersion is achieved by adding the lithium-loving nanoparticles to an N-methylpyrrolidone solution and stirring magnetically for 4-6 hours.

3. The method for preparing a composite multifunctional lithium metal anode according to claim 1, characterized in that, Specifically, the drying process involves vacuum drying the solution of lithium-philic nanoparticles coated on copper foil at 60-70°C for 12-16 hours.

4. The method for preparing a composite multifunctional lithium metal anode according to claim 1, characterized in that, The process of transferring the lithium-loving nanoparticle layer onto the lithium foil involves covering the lithium foil with copper foil, bringing the lithium-loving nanoparticle layer into contact with the lithium foil, pressing a weight onto the copper foil, and allowing it to stand for 10-30 minutes before peeling off the copper foil, thus transferring the lithium-loving nanoparticle layer onto the lithium foil.

5. The method for preparing a composite multifunctional lithium metal anode according to claim 1, characterized in that, The heating and evaporation parameters for the high ionic conductivity material are as follows: vacuum degree is 10. -4 -10 -6 Pa, heating power of 230-270W, evaporation rate of 3.5-7.5 Å / s.

6. A composite multifunctional lithium metal anode, characterized in that, It is prepared by the method described in any one of claims 1-5.

7. The application of a composite multifunctional lithium metal anode prepared by the preparation method according to any one of claims 1-5 in battery materials.

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