High-entropy lithium alloy material, preparation method, negative electrode material and battery

Abstract

The invention relates to the technical field of batteries, in particular to a high-entropy lithium alloy material, a preparation method, a negative electrode material and a battery. The preparation method provided by the invention comprises the following steps: grinding metal raw materials of lithium, aluminum, magnesium, tin and zinc into mixed powder; providing a lithium compensation agent, heating the mixed powder to a melting temperature in a protective gas atmosphere, adding the lithium compensation agent to form a molten mass, and cooling the molten mass based on a rapid quenching process to obtain a porous composite structure thin strip; the cooled porous composite structure thin strip is placed in an oxygen-containing gas atmosphere, zinc atoms, magnesium atoms and aluminum atoms on the surface of the porous composite structure thin strip react with oxygen, and a passivation layer is formed on the surface of the porous composite structure thin strip; performing fluorination treatment on one side, far away from the porous composite structure thin strip, of the passivation layer to form a protection layer; and carrying out annealing treatment on the fluorinated porous composite structure thin strip to obtain the high-entropy lithium alloy material. The problem that volume expansion inhibition is insufficient when a high-entropy lithium alloy structure serves as a negative electrode material is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a high-entropy lithium alloy material, a preparation method, a negative electrode material and a battery. BACKGROUND

[0002] Traditional alloy negative electrodes will produce huge volume expansion during lithium intercalation, resulting in electrode pulverization and capacity reduction. In recent years, high-entropy materials have shown potential in structural buffering and interface regulation due to their unique lattice distortion effect and slow diffusion characteristics. However, the selection of elements and the design of structures in high-entropy lithium alloy material systems still lack systematic guidance, making it difficult to balance electrical conductivity, structural stability and interface compatibility. Therefore, a preparation method of high-entropy lithium alloy material is sought to prepare a high-entropy lithium alloy material with controllable composition and coordinated structure, so as to effectively suppress the volume effect of the negative electrode material and comprehensively improve the electrochemical performance. SUMMARY

[0003] In order to solve the problem of insufficient volume expansion suppression of the existing high-entropy lithium alloy structure as a negative electrode material, the present application provides a high-entropy lithium alloy material, a preparation method, a negative electrode material and a battery.

[0004] To solve the above technical problems, the present application provides the following technical solution: a preparation method of a high-entropy lithium alloy material, the preparation method of the high-entropy lithium alloy material comprising: providing metal raw materials of lithium, aluminum, magnesium, tin and zinc, grinding the metal raw materials of lithium, aluminum, magnesium, tin and zinc into a mixed powder; providing a lithium compensation agent, heating the mixed powder to a melting temperature under a protective gas atmosphere, then adding the lithium compensation agent to form a molten body, cooling the molten body based on a rapid quenching process, forming a nanocrystalline region and an amorphous region during the cooling process of the molten body, and obtaining a porous composite structure thin strip after cooling; placing the cooled porous composite structure thin strip in an oxygen-containing gas atmosphere, and reacting zinc atoms, magnesium atoms and aluminum atoms on the pore surface of the porous composite structure thin strip with oxygen to form a passivation layer completely covering the porous composite structure thin strip; performing fluorination treatment on the side of the passivation layer away from the porous composite structure thin strip to form a protective layer; annealing the porous composite structure thin strip after fluorination treatment, and tin atoms and lithium atoms in the porous composite structure thin strip form Li 22 Sn5, zinc atoms and lithium atoms form Li2Zn, and Li 22 Sn5 and Li2Zn form a buffer region between the nanocrystalline region and the amorphous region inside the porous composite structure thin strip, and the annealing treatment is completed to obtain a high-entropy lithium alloy material.

[0005] Preferably, grinding lithium, aluminum, magnesium, tin, and zinc metal raw materials into a mixed powder includes: providing lithium, aluminum, magnesium, tin, and zinc metal raw materials; pre-treating the metal raw materials into lithium, aluminum, magnesium, tin, and zinc metal powders, wherein the lithium metal powder has a particle size range of 1~10μm, and the aluminum, magnesium, tin, and zinc metal powders have a particle size range of 10~50nm; the mass ratio of lithium, aluminum, magnesium, tin, and zinc in the mixed powder is lithium:aluminum:magnesium:tin:zinc = (80~90%:2~6%:1~4%:1~5%:1~5%); providing a ball milling device, preheating the ball milling device to 600~800℃ at a heating rate of 5~10℃ / min, and after heating, placing the lithium, aluminum, magnesium, tin, and zinc metal powders in the ball milling device and grinding for 4~8 hours at a stirring speed of 100~400rpm and a ball-to-material ratio of (15:1~20:1) to obtain the mixed powder.

[0006] Preferably, the process of heating the mixed powder to a melting temperature under a protective gas atmosphere and then adding a lithium compensator to form a melt comprises: providing a lithium compensator, wherein the lithium compensator is any one or more combinations of lithium nitride or lithium oxide; heating the mixed powder from room temperature to a melting temperature of 1200-1300°C at a heating rate of 10-20°C / min under a protective gas atmosphere; and adding the lithium compensator after heating to the melting temperature, wherein the lithium compensator and the molten mixed powder form a melt.

[0007] Preferably, the cooling of the melt based on the rapid quenching process includes: providing a rapid quenching device, which is equipped with nozzles and single rollers spaced apart from the nozzles; controlling the linear velocity of the single roller surface to be 30±5 m / s, controlling the distance between the nozzle tip and the single roller surface to be 300±50 μm, spraying the melt through the nozzles onto the single roller surface for cooling under a protective gas atmosphere, wherein the pressure of the protective gas atmosphere is 0.6±0.1 bar, and after the melt comes into contact with the single roller surface, cooling it from 1200~1300℃ to room temperature. During the cooling process, zinc atoms and tin atoms in the melt aggregate to one side of the melt to form a zinc / tin region. After cooling, a porous composite structure thin strip is obtained.

[0008] Preferably, the reaction of zinc atoms, magnesium atoms, and aluminum atoms with oxygen to form a passivation layer on the surface of the porous composite structure thin strip includes: zinc atoms reacting with oxygen to obtain zinc oxide, magnesium atoms reacting with oxygen to obtain magnesium oxide, and aluminum atoms reacting with oxygen to obtain aluminum oxide; and zinc oxide, magnesium oxide, and aluminum oxide forming a passivation layer on the surface of the porous composite structure thin strip.

[0009] Preferably, the fluorination treatment on the side of the passivation layer away from the porous composite structure thin strip includes: providing argon and tetrafluoromethane gas, mixing the argon and tetrafluoromethane gas at a flow ratio of (1:1) to (3:1) to form a mixed gas; placing the porous composite structure thin strip forming the passivation layer in a vacuum environment and introducing the mixed gas, and treating it with plasma for 30 to 45 minutes at a power of 150 to 250 W and a room temperature to 60°C to form a protective layer on the side of the passivation layer away from the porous composite structure thin strip.

[0010] Preferably, the fluorinated porous composite structure thin strip is first heated to 150-200°C at a rate of 1-5°C / min, and held at that temperature for 30-60 minutes. During the first heating process, tin and lithium atoms inside the porous composite structure thin strip form Li 22 Sn5, zinc atoms and lithium atoms form Li2Zn, Li 22 Sn5 and Li2Zn form a buffer region between the nanocrystalline and amorphous regions inside the porous composite structure thin strip; after the first heat preservation, the temperature is raised to 300~400℃ for the second time and kept for 15~30 minutes. After the second heat preservation, the material is cooled to room temperature at 0~5℃ / min to obtain a high-entropy lithium alloy material.

[0011] To solve the above-mentioned technical problems, the present invention provides another technical solution as follows: a high-entropy lithium alloy material, prepared by the above-mentioned method for preparing high-entropy lithium alloy material, wherein the high-entropy lithium alloy material comprises a porous composite structure thin strip, a buffer region, a passivation layer, and a protective layer; the porous composite structure thin strip includes a nanocrystalline region and an amorphous region inside, and the buffer region is disposed in the region between the nanocrystalline region and the amorphous region; the passivation layer is disposed on the outer surface of the porous composite structure thin strip and completely covers the porous composite structure thin strip, and the protective layer is disposed on the side of the passivation layer away from the porous composite structure thin strip.

[0012] To solve the above-mentioned technical problems, the present invention provides another technical solution as follows: a negative electrode material, comprising a current collector stacked in layers and the above-mentioned high-entropy lithium alloy material.

[0013] To solve the above-mentioned technical problems, the present invention provides another technical solution as follows: a battery, the battery comprising a positive electrode material, an electrolyte and the above-mentioned high-entropy lithium alloy material.

[0014] Compared with the prior art, the high-entropy lithium alloy material, preparation method, negative electrode material, and battery provided by the present invention have the following beneficial effects: 1. A method for preparing a high-entropy lithium alloy material provided by an embodiment of the present invention, the method comprising: providing lithium, aluminum, magnesium, tin and zinc metal raw materials; grinding the lithium, aluminum, magnesium, tin and zinc metal raw materials into a mixed powder; providing a lithium compensator; heating the mixed powder to a melting temperature under a protective gas atmosphere and then adding the lithium compensator to form a melt; cooling the melt using a rapid quenching process; forming nanocrystalline and amorphous regions during the cooling process; obtaining a porous composite structure thin strip after cooling; placing the cooled porous composite structure thin strip in an oxygen-containing gas atmosphere; the zinc, magnesium and aluminum atoms on the pore surface of the porous composite structure thin strip reacting with oxygen to form a passivation layer that completely covers the porous composite structure thin strip; performing fluorination treatment on the side of the passivation layer away from the porous composite structure thin strip to form a protective layer; annealing the fluorinated porous composite structure thin strip; and forming a Li+ layer by annealing the tin and lithium atoms inside the porous composite structure thin strip. 22 Sn5, zinc atoms and lithium atoms form Li2Zn, Li 22 Sn5 and Li2Zn form a buffer region between the nanocrystalline and amorphous regions within the porous composite thin strip, and annealing completes the process to obtain a high-entropy lithium alloy material. This embodiment demonstrates the preparation of a high-entropy lithium alloy material with a multi-level buffer structure, enabling it to exhibit high capacity and high interfacial stability when used as an anode material.

[0015] 2. The present invention defines the grinding of lithium, aluminum, magnesium, tin, and zinc metal raw materials into a mixed powder as follows: providing lithium, aluminum, magnesium, tin, and zinc metal raw materials, and pretreating the metal raw materials into lithium, aluminum, magnesium, tin, and zinc metal powders, wherein the particle size range of lithium metal powder is 1~10μm, and the particle size range of aluminum, magnesium, tin, and zinc metal powders is 10~50nm. The lithium metal powder has a larger particle size compared to the other metal powders. Lithium is an extremely reactive alkali metal; using micron-sized lithium powder can effectively reduce the specific surface area and the area in contact with air, thereby reducing the risk of oxidation and thermal runaway. Furthermore, if the lithium metal powder particle size is small, lithium particles are prone to agglomeration and are difficult to disperse uniformly. The mass ratio of lithium, aluminum, magnesium, tin, and zinc in the mixed powder is lithium:aluminum:magnesium:tin:zinc = (80~90% : 2~6% : 1~4% : 1~5% : 1~5%). A ball mill is provided, preheated to 600~800℃ at a heating rate of 5~10℃ / min. After heating, the lithium, aluminum, magnesium, tin, and zinc metal powders are placed in the ball mill and ground for 4~8 hours with a stirring speed of 100~400rpm and a ball-to-material ratio of (15:1~20:1) to obtain the mixed powder. Through the synergistic design of metal powder classification pretreatment and high-energy ball milling, the technical problems of poor compositional uniformity and lithium volatilization loss in traditional lithium alloy preparation are solved.

[0016] 3. The present invention defines the process of heating a mixed powder to a melting temperature under a protective gas atmosphere and then adding a lithium compensator to form a melt, comprising: providing a lithium compensator, wherein the lithium compensator is any one or more combinations of lithium nitride or lithium oxide; heating the mixed powder from room temperature to a melting temperature of 1200-1300°C at a heating rate of 10-20°C / min under a protective gas atmosphere; and adding the lithium compensator after heating to the melting temperature, wherein the lithium compensator and the molten mixed powder form a melt. This embodiment, through the dynamic regulation of the lithium compensator, precise temperature control, and the synergistic design of the protective atmosphere, avoids lithium volatilization loss and compositional unevenness during high-temperature melting.

[0017] 4. The rapid quenching process for cooling molten material as defined in this invention includes: providing a rapid quenching device, which is equipped with nozzles and single rollers spaced apart from the nozzles; controlling the linear velocity of the single roller surface to be 30±5 m / s, and controlling the distance between the nozzle tip and the roller surface to be 300±50 μm; spraying the molten material through the nozzles onto the roller surface under a protective gas atmosphere for cooling, wherein the pressure of the protective gas atmosphere is 0.6±0.1 bar; after the molten material contacts the roller surface, cooling from 1200~1300℃ to room temperature; during the cooling process, zinc and tin atoms in the molten material aggregate to one side of the molten material to form a zinc / tin region; and obtaining a porous composite structure thin strip after cooling. This embodiment enables the rapid acquisition of amorphous / nanocrystalline phases in high-entropy lithium alloy materials through a rapid quenching process.

[0018] 5. The present invention defines the reaction of zinc atoms, magnesium atoms, and aluminum atoms with oxygen to form a passivation layer on the surface of a porous composite structure thin strip. This includes: an oxygen-containing gas atmosphere referring to an air environment, i.e., an oxygen content of less than or equal to 21%; zinc atoms reacting with oxygen to obtain zinc oxide, magnesium atoms reacting with oxygen to obtain magnesium oxide, and aluminum atoms reacting with oxygen to obtain aluminum oxide; and zinc oxide, magnesium oxide, and aluminum oxide forming a passivation layer on the surface of the porous composite structure thin strip. This embodiment, through micro-oxygen regulation and multi-element synergistic oxidation, constructs a stable in-situ passivation layer, improving the stability and cycle life of high-entropy lithium alloys in air.

[0019] 6. The fluorination treatment on the side of the passivation layer away from the porous composite structure thin strip as defined in this invention includes: providing argon and tetrafluoromethane gas, mixing the argon and tetrafluoromethane gas at a flow ratio of (1:1) to (3:1) to form a mixed gas; placing the porous composite structure thin strip forming the passivation layer in a vacuum environment and introducing the mixed gas, and then treating it with plasma for 30 to 45 minutes at a power of 150 to 250 W and a room temperature to 60°C to form a protective layer on the side of the passivation layer away from the porous composite structure thin strip. By optimizing the gas ratio and plasma parameters to form a protective layer, interface protection is provided for high-entropy lithium alloy materials. The application of high-entropy lithium alloys in batteries can improve the cycle life of the batteries.

[0020] 7. The annealing treatment of the fluorinated porous composite structure thin strip as defined in this invention includes: heating the fluorinated porous composite structure thin strip to 150-200°C for the first time at a rate of 1-5°C / min, and holding at that temperature for 30-60 minutes for the first time, wherein tin atoms and lithium atoms inside the porous composite structure thin strip form Li 22 Sn5, zinc atoms and lithium atoms form Li2Zn, Li 22 Sn5 and Li2Zn form a buffer region between the nanocrystalline and amorphous regions within the porous composite thin strip. After the first heating, a second heating to 300-400℃ is performed, followed by a second heating for 15-30 minutes. After the second heating, the material is cooled to room temperature at a rate of 0-5℃ / min to obtain a high-entropy lithium alloy. Annealing treatment controls the distribution of internal stress and the buffer region, enabling the high-entropy lithium alloy to possess high capacity and long-term cycling stability.

[0021] 9. This invention also provides a high-entropy lithium alloy material, prepared by the above-described method for preparing high-entropy lithium alloy materials. The high-entropy lithium alloy material includes a porous composite structure thin strip, a buffer region, a passivation layer, and a protective layer. The porous composite structure thin strip includes nanocrystalline and amorphous regions, with the buffer region positioned between the nanocrystalline and amorphous regions. The passivation layer is disposed on the outer surface of the porous composite structure thin strip and completely covers it. The protective layer is disposed on the side of the passivation layer away from the porous composite structure thin strip. This solves the problem of structural failure and interface instability in traditional lithium alloy anodes caused by repeated volume changes during cycling.

[0022] 10. This invention also provides a negative electrode material, comprising a current collector stacked in layers and the aforementioned high-entropy lithium alloy material. The high-entropy lithium alloy material maintains its structural integrity during cycling, thereby enabling it to combine with the current collector to obtain a negative electrode material with good anti-expansion properties.

[0023] 10. This embodiment of the invention also provides a battery, the battery comprising a positive electrode material, an electrolyte, and the aforementioned high-entropy lithium alloy material. The negative electrode material of this embodiment exhibits superior anti-expansion performance throughout the entire cycle, thereby providing the battery with stable capacity output and long cycle life. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic flowchart of the preparation method of the high-entropy lithium alloy material provided in the first embodiment of the present invention.

[0026] Figure 2 This is a schematic diagram of the porous composite thin strip structure provided in the first embodiment of the present invention.

[0027] Figure 3 yes Figure 2 A magnified view of region A in the middle.

[0028] Figure 4 This is a schematic diagram of the structure after the passivation layer of the first embodiment of the present invention completely covers the porous composite strip structure.

[0029] Figure 5 This is a schematic diagram of the structure of the high-entropy lithium alloy material after annealing provided in the first embodiment of the present invention.

[0030] Figure 6 yes Figure 5 A magnified view of region B in the middle.

[0031] Figure 7 This is a schematic diagram of the structure of the high-entropy lithium alloy material provided in the second embodiment of the present invention.

[0032] Figure 8 yes Figure 7 A magnified view of region C in the middle. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0034] In the embodiments provided by this invention, it should be understood that "B corresponding to A" means that B is associated with A, and B can be determined based on A. However, it should also be understood that determining B based on A does not mean determining B solely based on A; B can also be determined based on A and / or other information.

[0035] It should be understood that the phrase "one embodiment" or "an embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of the invention. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Those skilled in the art should also recognize that the embodiments described in the specification are optional embodiments, and the actions and modules involved are not necessarily essential to the invention.

[0036] In various embodiments of the present invention, it should be understood that the sequence number of each process does not necessarily imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process defined by the present invention.

[0037] The flowcharts and block diagrams in the accompanying drawings illustrate methods and possible architectures, functions, and operations according to various embodiments of this application. In this regard, each block in the flowchart or block diagram may represent part of a step. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, or they may sometimes be executed in reverse order, depending on the functions involved.

[0038] Traditional alloy anodes experience significant volume expansion during lithium intercalation, leading to electrode pulverization and a sharp decrease in capacity. In recent years, high-entropy materials have shown potential in structural buffering and interface control due to their unique lattice distortion effect and slow diffusion characteristics. However, in high-entropy lithium alloy systems, element selection and structural design still lack systematic guidance, making it difficult to simultaneously achieve conductivity, structural stability, and interface compatibility. Therefore, this study seeks a method for preparing high-entropy lithium alloy materials with controllable composition and synergistic structure to effectively suppress the volume effect of anode materials and comprehensively improve electrochemical performance.

[0039] please Figure 1 The first embodiment of the present invention provides a method for preparing a high-entropy lithium alloy material, the method comprising: S1 provides metallic raw materials of lithium, aluminum, magnesium, tin and zinc, and grinds the metallic raw materials of lithium, aluminum, magnesium, tin and zinc into a mixed powder; S2 provides a lithium compensator. The mixed powder is heated to the melting temperature under a protective gas atmosphere and then the lithium compensator is added to form a melt. The melt is cooled based on a rapid quenching process. During the cooling process, nanocrystalline and amorphous regions are formed. After cooling, a porous composite structure thin strip is obtained. S3, the cooled porous composite structure thin strip is placed in an oxygen-containing gas atmosphere, and the zinc atoms, magnesium atoms and aluminum atoms on the pore surface of the porous composite structure thin strip react with oxygen to form a passivation layer that completely covers the porous composite structure thin strip. S4, a protective layer is formed by fluorination on the side of the passivation layer away from the porous composite structure thin strip; and S5, the fluorinated porous composite structure thin strip is annealed, and the tin atoms and lithium atoms inside the porous composite structure thin strip form Li 22Sn5, zinc atoms and lithium atoms form Li2Zn, Li 22 Sn5 and Li2Zn form a buffer region between the nanocrystalline and amorphous regions inside the porous composite thin strip, and the high-entropy lithium alloy material is obtained after annealing.

[0040] Understandably, this embodiment utilizes the synergistic design of multiple metal components and multi-stage process control. Specifically, please refer to... Figure 2 and Figure 3 In step S1, five metals—lithium, aluminum, magnesium, tin, and zinc—are selected and ground together to form a mixed powder. Grinding ensures that the five metals are uniformly dispersed at the atomic level. Lithium is the primary electrochemically active element used in anode materials; aluminum and magnesium improve alloy strength, reduce density, and form a dense composite oxide passivation layer in situ on the surface after air exposure; tin and zinc form high-capacity intermetallic compound phases with lithium. These phases segregate at grain boundaries, acting as buffer zones to effectively suppress lithium dendrite growth and accommodate volume changes. The amorphous region exhibits high uniformity and elastic limit, effectively dissipating and redistributing stress through uniform plastic deformation, thereby suppressing the initiation and propagation of microcracks. Further, in step S2, melting is performed under a protective atmosphere, and a lithium compensator is introduced, followed by rapid quenching for cooling. The extremely high cooling rate during rapid quenching suppresses long-range atomic diffusion and ordered arrangement, allowing the melt to simultaneously form nanocrystalline and amorphous regions upon solidification. The nanocrystalline region acts as a strength support, providing mechanical stability; the amorphous region, on the other hand, possesses better toughness and can effectively dissipate stress. These two regions intertwine to form a composite structure that combines both toughness and strength. Simultaneously, the rapid quenching process creates a porous structure within the porous composite strip. These pores not only provide additional channels for lithium-ion migration but, more importantly, reserve buffer space for the volume expansion of the negative electrode material, thereby mitigating the damage to the overall structure caused by volume changes at the source. In this embodiment, the porous composite strip contains amorphous / nanocrystalline components, thus enabling it to adapt to stress changes from repeated lithiation / delithiation.

[0041] Furthermore, please combine them together. Figure 3 and Figure 4In step S3, the porous composite structure thin strip is placed in an oxygen-containing gas atmosphere. Utilizing the high affinity of zinc, magnesium, aluminum, and other metal elements for oxygen, they preferentially react with oxygen on the pore surface and the outer surface of the material, generating a dense metal oxide passivation layer. This passivation layer effectively isolates the internal active lithium from external air and moisture, significantly improving the air stability of the porous composite structure thin strip. Further, the fluorination treatment in step S4 constructs a protective layer rich in metal fluorides on the outside of the passivation layer. The fluoride layer possesses excellent chemical inertness and electrochemical stability, especially in the lithium-ion battery electrolyte environment, effectively suppressing side reactions and reducing irreversible consumption of active lithium. The protective layer and the passivation layer, from the two dimensions of physical barrier and chemical stability respectively, jointly ensure the interfacial integrity of the high-entropy lithium alloy material during long-term cycling.

[0042] Furthermore, please combine them together. Figure 5 and Figure 6 The annealing process in step S5 allows atoms within the porous composite structure thin strip to acquire sufficient migration ability under heating conditions, promoting the formation of Li from tin and lithium. 22 The Sn5 alloy phase, with zinc and lithium forming a Li2Zn alloy phase. The resulting lithium alloy phase is not randomly distributed but precipitates at the interface between the nanocrystalline and amorphous regions, thus creating a uniformly distributed buffer region within the porous composite thin strip. This buffer region, through its different volume change behavior compared to the matrix during charging and discharging, more effectively coordinates the uneven expansion and contraction between the hard nanocrystalline and soft amorphous phases during charging and discharging, minimizing local stress concentration. It should be understood that this embodiment prepares a high-entropy lithium alloy material with a multi-level buffer structure, enabling it to possess high capacity and high interfacial stability when used as a negative electrode material.

[0043] Specifically, in step S1 above, grinding the metallic raw materials of lithium, aluminum, magnesium, tin, and zinc into a mixed powder includes: Provides lithium, aluminum, magnesium, tin and zinc metal raw materials, pre-processes the metal raw materials into lithium, aluminum, magnesium, tin and zinc metal powders, wherein the lithium metal powder particle size ranges from 1 to 10 μm, and the aluminum, magnesium, tin and zinc metal powder particle size ranges from 10 to 50 nm, and the mass ratio of lithium, aluminum, magnesium, tin and zinc in the mixed powder is lithium:aluminum:magnesium:tin:zinc = (80~90% : 2~6% : 1~4% : 1~5% : 1~5%). Provide ball milling equipment. Preheat the ball milling equipment to 600-800℃ at a heating rate of 5-10℃ / min. After heating, place the metal powders of lithium, aluminum, magnesium, tin and zinc into the ball milling equipment and grind them for 4-8 hours at a stirring speed of 100-400rpm and a ball-to-material ratio of (15:1-20:1) to obtain mixed powder.

[0044] This embodiment solves the technical problems of poor compositional uniformity and lithium volatilization loss in traditional lithium alloy preparation by synergistically designing a metal powder classification pretreatment process and a high-energy ball milling process. The selective particle size range of the metal powder compared to other metal powders reduces the oxidation risk of highly active lithium powder. Simultaneously, the high dispersibility of nanoparticles promotes atomic-level mixing, and the combination of a ball-to-powder ratio of (15:1~20:1) and mechanical energy input at a rotation speed of 100~400 rpm effectively avoids stratification caused by density differences. Optionally, the lithium metal powder particle size range can also be 1~5 μm, 4~10 μm, or 3~8 μm. The aluminum, magnesium, tin, and zinc powder particle size ranges can also be 15~35 μm, 20~40 μm, or 3~30 μm.

[0045] Specifically, the ball milling process at 600-800℃ lowers the atomic diffusion energy barrier, enabling low-temperature alloying and suppressing lithium metal volatilization. A 4-8 hour ball milling cycle balances the powder cold welding and crushing rates, ensuring minimal particle size variation for powders of the same metal in the mixed powder. 80-90% lithium ensures sufficient lithium storage capacity, while 2-6% aluminum and 1-4% magnesium form a passivation layer that provides stability to the high-entropy lithium alloy. The 1-5% tin-zinc content forms a buffer region through grain boundary segregation, which suppresses dendrite formation.

[0046] Further, in step S2 above, heating the mixed powder to the melting temperature under a protective gas atmosphere and then adding a lithium compensator to form a melt includes: Provide a lithium compensator, wherein the lithium compensator is any one or more combinations of lithium nitride or lithium oxide; The mixed powder was heated from room temperature to a melting temperature of 1200-1300°C at a heating rate of 10-20°C / min under a protective gas atmosphere; After heating to the melting temperature, lithium compensator is added, and the lithium compensator and the molten mixed powder form a melt.

[0047] Understandably, this embodiment avoids lithium volatilization loss and compositional unevenness during high-temperature melting by adding a lithium compensator and precise temperature control, thus compensating for and offsetting the unavoidable lithium volatilization loss during high-temperature smelting. Lithium is easily volatilized at temperatures above 1200℃. By selecting lithium nitride or lithium oxide as a compensator, it decomposes and releases metallic lithium at a melting temperature of 1200℃~1300℃, filling the lithium vacancies caused by volatilization. At the same time, the trace gases generated by decomposition form a protective interface layer on the surface of the melt, inhibiting secondary oxidation. The linear heating rate of 10~20℃ / min ensures that the internal temperature gradient of the mixed powder changes little, avoiding local overheating that leads to preferential lithium volatilization; the 1200~1300℃ melting range balances the complete melting of high-melting-point metals and the control of lithium vapor pressure, reducing lithium volatilization through thermodynamic equilibrium and ensuring the uniformity of the melt composition. The protective gas atmosphere can be helium or argon, the specific function of which is to effectively isolate air and moisture, avoid the generation of impurities such as Li2O and LiOH, and ensure the quality of subsequent rapid quenching forming. It should be understood that this embodiment avoids lithium volatilization loss during high-temperature melting by adding a lithium compensator and controlling the temperature, and at the same time obtains a melt with highly uniform composition and in a high energy state, which facilitates subsequent rapid quenching to obtain a uniform amorphous / nanocrystalline composite structure.

[0048] Furthermore, please combine Figure 2 and Figure 3 In step S2 above, cooling the melt based on the rapid quenching process includes: Provide rapid quenching equipment, which is equipped with nozzles and single rollers spaced apart from the nozzles; The linear velocity of the single roller surface is controlled at 30±5 m / s, and the distance between the nozzle tip and the roller surface is controlled at 300±50 μm. The melt is sprayed through the nozzle onto the roller surface of the single roller under a protective gas atmosphere for cooling. The pressure of the protective gas atmosphere is 0.6±0.1 bar. After the melt comes into contact with the roller surface of the single roller, it is cooled from 1200~1300℃ to room temperature. During the cooling process, zinc atoms and tin atoms in the melt aggregate to one side of the melt to form a zinc / tin region. After cooling, a porous composite structure thin strip is obtained.

[0049] Understandably, this embodiment utilizes a rapid quenching process to form the amorphous / nanocrystalline phase in the high-entropy lithium alloy material. The rapid quenching process achieves non-equilibrium solidification through ultra-fast cooling. Instead of setting a fixed cooling rate, it rapidly cools the melt using the process parameters of the rapid quenching equipment. Specifically, the synergistic effect of the rapid quenching process parameters is reflected in the single-roller linear speed, nozzle distance, and protective gas pressure. Controlling the single-roller linear speed and nozzle distance ensures sufficient contact between the melt and the roll surface to form a uniform thin strip; the slightly positive pressure protective atmosphere ensures stable melt flow and avoids oxidation contamination. Ultra-fast cooling inhibits grain growth through a kinetic inhibition effect, forming an amorphous / nanocrystalline composite structure and providing abundant lithium diffusion channels. Simultaneously, the temperature gradient induces the directional migration and enrichment of zinc and tin atoms, preparing the Li2Zn / Li2 composite for subsequent annealing. 22 The formation of the Sn5 buffer region is a prerequisite for its development. The porous structure formed during rapid quenching is achieved through the synergistic effect of gas escape, volume shrinkage, and thermal expansion differences. This mitigates the volume expansion of lithium deposition, allowing high-entropy lithium alloy materials used as anode materials to increase the contact area between the electrode and electrolyte, promote wetting, and improve interface stability. The porous composite structure strips formed during rapid quenching also exhibit a porous structure, where the pores can provide buffer space for the expansion of the anode material.

[0050] Furthermore, please combine Figure 3 and Figure 4 In step S3 above, the reaction of zinc atoms, magnesium atoms, and aluminum atoms with oxygen to form a passivation layer on the surface of the porous composite structure thin strip includes: Zinc atoms react with oxygen to produce zinc oxide, magnesium atoms react with oxygen to produce magnesium oxide, and aluminum atoms react with oxygen to produce aluminum oxide. Zinc oxide, magnesium oxide, and aluminum oxide form a passivation layer on the surface of the porous composite strip.

[0051] Understandably, the oxide layer on the surface of traditional lithium alloys is uneven. This embodiment utilizes an oxygen-containing gas atmosphere control and a multi-element synergistic oxidation mechanism to construct a continuous and dense passivation layer on the surface of a porous composite structure thin strip. This passivation layer, composed of Al2O3, MgO, and ZnO composite oxides, possesses advantages such as strong interfacial bonding and uniform thickness. In this embodiment, the oxygen-containing gas atmosphere refers to an air environment, i.e., an oxygen content of less than or equal to 21%, to avoid discontinuous passivation layer due to low oxygen levels and to prevent excessive oxidation and brittle layer formation caused by high oxygen levels. Zinc, magnesium, and aluminum preferentially oxidize based on chemical activity, and the resulting composite oxides form a passivation layer covering the surface of the porous composite structure thin strip. This passivation layer essentially covers the surface of the porous composite structure thin strip, serving as a stable pre-layer for the solid electrolyte interface in the battery system. It effectively blocks direct contact between the electrolyte and the alloy substrate, thereby suppressing side reactions and uncontrolled lithium dendrite growth, significantly improving the air exposure tolerance and electrochemical cycle life of the high-entropy lithium alloy material.

[0052] Furthermore, please combine Figure 4 and Figure 5 In step S4 above, the fluorination treatment on the side of the passivation layer away from the porous composite structure thin strip includes: Argon and tetrafluoromethane gas are provided, and the argon and tetrafluoromethane gas are mixed in a flow ratio of (1:1) to (3:1) to form a mixed gas; The porous composite structure thin strip with the passivation layer is placed in a vacuum environment and a mixed gas is introduced. Then, it is subjected to plasma treatment for 30 to 45 minutes at a power of 150 to 250 W and a room temperature to 60°C to form a protective layer on the side of the passivation layer away from the porous composite structure thin strip.

[0053] Understandably, in this embodiment, the concentration of active fluorine species in the plasma is regulated by controlling the flow ratio of argon and tetrafluoromethane to (1:1) to (3:1). A high argon ratio enhances bombardment energy and promotes molecular fragmentation, while a high tetrafluoromethane ratio increases the fluorine source supply, ensuring a uniform and continuous protective layer. Specifically, the protective layer can be lithium fluoride. A power of 150~250W activates gas molecules to avoid damaging the passivation layer. Within a temperature range from room temperature to 60°C, the lower temperature effectively prevents the porous structure from being damaged by thermal stress. A suitable time balances the growth and crystallinity of the protective layer, promoting the growth of columnar crystals with high ionic conductivity. The protective layer can complement the passivation layer, with the passivation layer providing a physical barrier and the protective layer promoting lithium-ion diffusion. Plasma treatment is a technique that uses high-energy plasma to modify the surface of materials. Plasma, as the fourth state of matter, is composed of partially ionized gas containing electrons, ions, neutral particles, etc., and has high reactivity. Through physical collisions or chemical reactions between plasma and material surfaces, the chemical composition, microstructure, and interfacial properties of the surface can be altered, achieving functions such as surface cleaning, activation, etching, or coating deposition. In this embodiment, a protective layer is formed using plasma treatment. This protective layer works synergistically with the passivation layer: the passivation layer primarily provides physical barriers to prevent bulk oxidation; while the protective layer, as an artificial solid-state electrolyte interface, uses its high interfacial energy to guide uniform lithium ion deposition, effectively suppressing lithium dendrite growth. Simultaneously, the hydrophobic properties of the protective layer help reduce electrolyte side reactions and lower interfacial impedance.

[0054] Furthermore, please combine Figure 5 and Figure 6 In step S5 above, the annealing treatment of the fluorinated porous composite structure thin strip includes: The fluorinated porous composite thin strip was first heated to 150-200℃ at a rate of 1-5℃ / min, and held at that temperature for 30-60 minutes. During the first heating process, tin and lithium atoms inside the porous composite thin strip formed Li 22Sn5, zinc atoms and lithium atoms form Li2Zn, Li 22 Sn5 and Li2Zn form a buffer region between the nanocrystalline and amorphous regions inside the porous composite structure thin strip; after the first heat preservation, the temperature is raised to 300℃~400℃ for the second heat preservation for 15~30 minutes. After the second heat preservation, the material is cooled to room temperature at 0~5℃ / min to obtain a high-entropy lithium alloy material.

[0055] Understandably, annealing, through precise control of the heating rate and holding time, guides the directional diffusion of tin and zinc atoms and their reaction with lithium to form Li. 22 The Sn5 / Li2Zn buffer region forms a buffer zone between the nanocrystalline and amorphous regions. Specifically, a stepwise heating method is used to raise the temperature to 200℃ at a rate of 3~5℃ / min and hold it for 60 minutes to gently release internal stress and avoid stress concentration leading to microcracks; the temperature is then raised to 400℃ and held for 30 minutes to promote the segregation of tin and zinc atoms towards the grain boundaries and their in-situ reaction with lithium to generate uniformly distributed Li. 22 Sn5 / Li2Zn buffer region. Where Li 22 The low volume expansion of Sn5 and the high plasticity of Li2Zn synergistically mitigate volume changes, enhance interfacial bonding strength, suppress dendrite growth, and improve cycle stability. Finally, slow cooling at 0–5 °C / min avoids thermal shock, ensuring the buffer region precipitates with a thermodynamically stable structure, reducing interfacial stress caused by differences in thermal expansion coefficients, and guaranteeing the integrity of the porous composite strip. The annealing treatment in this embodiment regulates internal stress and buffer region distribution, enabling the high-entropy lithium alloy to possess both high capacity and long cycle stability.

[0056] Please combine Figure 7 and Figure 8 The second embodiment of the present invention further provides a high-entropy lithium alloy material, which is prepared by the above-described method for preparing high-entropy lithium alloy material. The high-entropy lithium alloy material includes a porous composite structure thin strip, a buffer region, a passivation layer, and a protective layer. The porous composite structure thin strip includes a nanocrystalline region and an amorphous region inside, and a buffer region is provided between the nanocrystalline region and the amorphous region. The passivation layer is disposed on the outer surface of the porous composite structure thin strip and completely covers the porous composite structure thin strip. The protective layer is disposed on the side of the passivation layer away from the porous composite structure thin strip.

[0057] Specifically, the thickness of the porous composite structure thin strip is 50 nm to 500 nm. This porous composite structure shortens the diffusion distance of lithium ions within the material, facilitating rapid charge and discharge and improving rate performance. The protective layer, 10–15 nm thick, acts as a stable artificial solid-state electrolyte interface, effectively suppressing side reactions between the electrolyte and electrode materials and reducing irreversible consumption of active lithium. The passivation layer, 8–12 nm thick, forms a dense, continuous oxide layer that effectively isolates air and moisture, preventing corrosion and loss of internal active lithium and significantly improving the material's stability in air.

[0058] Understandably, the high-entropy lithium alloy material provided in this embodiment solves the problem of structural failure and interface instability caused by repeated volume changes during cycling in traditional lithium alloy anodes. Specifically, a porous composite structure thin strip constitutes the matrix of the high-entropy lithium alloy material. Its interior is formed by the interweaving of nanocrystalline and amorphous regions to create a composite structure. The nanocrystalline regions act as a robust framework, providing the material with the necessary mechanical strength to prevent overall plastic deformation or collapse during charging and discharging; while the amorphous regions have higher atomic disorder and free volume, enabling the material to possess toughness and stress dissipation capabilities. This allows the high-entropy lithium alloy material to effectively absorb and disperse the internal stress generated by lithium-ion insertion / extraction, significantly suppressing the initiation and propagation of microcracks. Furthermore, the uniformly distributed porous structure within the high-entropy lithium alloy material provides a pre-defined accommodating space for the volume expansion of the active material during cycling, thereby significantly reducing the destructive force of volume changes on the overall structural integrity.

[0059] Specifically, in the interface region between the nanocrystalline region and the amorphous region, a special layer of Li was set up. 22A buffer region composed of lithium alloy phases such as Sn5 and Li2Zn is formed during annealing and is tightly bonded to the nanocrystalline and amorphous regions. When charging and discharging cause uneven expansion or contraction of different phase regions, this buffer region can coordinate the deformation differences between adjacent regions through its own elastic deformation, effectively passivating stress concentration at the phase boundaries and avoiding debonding or cracking caused by weak interface bonding. The passivation layer is mainly composed of oxides of metals such as zinc, magnesium, and aluminum. It completely covers the outer surface of the porous strip and the inner surface of the pores, forming the first physical and chemical barrier. This passivation layer can effectively prevent moisture and oxygen from the environment from penetrating into the material, significantly improving the storage stability and processing feasibility of the material. At the same time, this oxide layer is firmly bonded to the substrate, providing stable support for the external protective layer. The protective layer set outside the passivation layer is enriched with metal fluoride components through fluorination treatment, which can greatly suppress the occurrence of harmful side reactions between the electrode material and the electrolyte, reduce the loss of active lithium and the formation of irreversible phases. The passivation layer ensures physical protection, while the protective layer focuses on the stability of the electrochemical interface. This ensures that the high-entropy lithium alloy material can maintain a thin and stable solid electrolyte interface film during long-term electrochemical cycling, thereby guaranteeing high coulombic efficiency and long cycle life.

[0060] To verify the effectiveness of the high-entropy lithium alloy material provided in this embodiment, the following experiment was conducted: Experimental group: Step 1: Provide lithium, aluminum, magnesium, tin and zinc metal powders with a purity of 99.9%, and ball mill them at 800℃ for 8 hours at a speed of 400 rpm and a ball-to-material ratio of 20:1 to obtain a mixed powder.

[0061] Step 2: Under a helium atmosphere, the mixed powder is heated to 1300℃ and lithium nitride is added to form a melt. The melt is driven by a pressure of 0.6 bar and ejected through a 0.8 mm quartz nozzle slit. The distance between the nozzle tip and the surface of the high-speed rotating copper roller is maintained at 300 μm, and the linear velocity of the roller surface is controlled at 30 m / s. After the melt cools on the surface of the copper roller, a porous composite structure thin strip is obtained, and a passivation layer is naturally formed on the surface of the porous composite structure thin strip.

[0062] Step 3: The porous composite structure thin strip with the passivation layer is placed into the chamber. The chamber is then evacuated to a vacuum level below 1×10⁻³ Pa. A mixture of argon and tetrafluoromethane is introduced, with the flow ratio of Ar to CF4 controlled at 1:1, maintaining the chamber working pressure at 20 Pa. Subsequently, the radio frequency power supply is turned on, and the process is carried out for 30 minutes at 250 W and 60°C. High-purity Ar gas is then introduced to flush the chamber. Finally, a dense and uniform lithium fluoride protective layer is obtained on the surface of the porous composite structure thin strip with the passivation layer.

[0063] Step 4: Place the porous composite structure thin strip with the protective layer in a vacuum-protected heat treatment furnace. First, heat it to 200°C at a rate of 5°C / min and hold it for 60 minutes to eliminate internal stress. Then, continue heating it to 300°C at the same rate and hold it for 120 minutes. Finally, heat it to 400°C and hold it for 30 minutes. After completion, cool it to room temperature with the furnace to obtain a high-entropy lithium alloy material, which is used as the negative electrode material.

[0064] Comparative Group 1: Pure lithium metal foil as the negative electrode material; Comparison Group 2: Binary Lithium Alloy Li 20 Sn5 as a negative electrode material Comparative Group 3: The procedure was the same as the experimental group, except that the ingot alloy obtained was not subjected to rapid quenching and annealing treatment and was used as the negative electrode material. Comparative Group 4: The procedure is the same as the experimental group, except that the sample that has not undergone plasma fluorination treatment is used as the negative electrode material.

[0065] Volume expansion rate: The negative electrode materials of the experimental group and the control group were respectively made into CR2032 button batteries, with lithium sheet as counter electrode and 1 mol LiPF8 / EC:DMC (volume ratio of 1:1) as electrolyte; after 50 cycles at 0.1C, the particle size change was observed by electron microscopy and the volume expansion rate was calculated.

[0066] Li⁺ diffusion coefficient: The electrochemical workstation performed EIS tests on the negative electrode materials of the experimental and control groups. The chemical diffusion coefficient of lithium ions was calculated based on the Warburg impedance fitting in the low-frequency region. Warburg impedance is an impedance form that describes diffusion control in electrochemistry. Warburg impedance can describe the resistive component of electron transfer in electrolyte solution under diffusion control.

[0067] Cycling performance: Half-cells were made from the negative electrode materials of the experimental and control groups. The first charge-discharge curves were tested at a rate of 0.1C, and the first coulombic efficiency was calculated. The capacity retention rate was recorded after 200 cycles at a rate of 0.5C.

[0068] Experimental results: Table 1, Performance Indicator Table

[0069] As can be seen from the results in Table 1, the high-entropy lithium alloy material prepared in this embodiment, as an anode material, is significantly superior to all comparative examples in terms of high initial efficiency, long cycle life, low volume expansion, and excellent environmental stability.

[0070] The third embodiment of this invention provides a negative electrode material, including a current collector stacked in layers and the aforementioned high-entropy lithium alloy material. Understandably, the high-entropy lithium alloy material is stacked on top of the current collector in the form of a thin strip. The porous composite matrix, amorphous / nanocrystalline dual-phase structure, and interface buffer region within the high-entropy lithium alloy material work synergistically. During charge-discharge cycles, the active material inevitably undergoes volume expansion and contraction. The porous structure within the high-entropy lithium alloy material provides the primary space to accommodate these volume changes, while the amorphous / nanocrystalline structure within the high-entropy lithium alloy material, through its own toughness deformation and strength support, transforms macroscopic volume deformation into microscopic stress absorption and dispersion, greatly suppressing the overall plastic deformation of the negative electrode material. The buffer region located at the amorphous / nanocrystalline grain boundaries further passivates internal stress concentration, preventing microcracks from initiating and propagating from within the material. The protective layer and passivation layer, from the perspectives of physical barrier and chemical stability, jointly ensure the interfacial integrity of the negative electrode material during long-term cycling. In this embodiment, the high-entropy lithium alloy material can maintain the integrity of its structure during cycling, thus enabling it to be combined with the current collector to obtain a negative electrode material with good anti-expansion performance.

[0071] The fourth embodiment of this invention discloses a battery comprising a positive electrode material, an electrolyte, and the aforementioned negative electrode material. Understandably, during charging and discharging, lithium ions repeatedly insert and extract between the positive and negative electrodes. When lithium ions insert into the negative electrode material, the porous composite structure within the negative electrode material initially provides expansion space. Its internal amorphous / nanocrystalline dual-phase composite matrix effectively absorbs and disperses the lattice stress generated by lithium ion insertion through its own toughness, deformation, and strength support, preventing the pulverization of the active material particles. The buffer region located at the dual-phase interface further coordinates the deformation differences between the different phases, minimizing local stress concentrations that could lead to structural damage. The protective layer and passivation layer together ensure the interfacial integrity of the negative electrode material in the battery during long-term cycling. The negative electrode material of this embodiment maintains its physical structural integrity throughout the entire cycling process, thereby providing the battery with stable capacity output and a long cycle life.

[0072] The foregoing has provided a detailed description of the preparation method of a high-entropy lithium alloy material, the high-entropy lithium alloy material itself, the preparation method, and the anode material disclosed in the embodiments of the present invention. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention. Any modifications, equivalent substitutions, and improvements made within the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a high-entropy lithium alloy material, characterized in that: The preparation method of the high-entropy lithium alloy material includes: Provide metallic raw materials of lithium, aluminum, magnesium, tin and zinc, and grind the metallic raw materials of lithium, aluminum, magnesium, tin and zinc into mixed powder; A lithium compensator is provided. The mixed powder is heated to the melting temperature under a protective gas atmosphere and then the lithium compensator is added to form a melt. The melt is cooled based on a rapid quenching process. During the cooling process, nanocrystalline and amorphous regions are formed in the melt. After cooling, a porous composite structure thin strip is obtained. The cooled porous composite structure strip is placed in an oxygen-containing gas atmosphere. The zinc, magnesium and aluminum atoms on the pore surface of the porous composite structure strip react with oxygen to form a passivation layer that completely covers the porous composite structure strip. A protective layer is formed by fluorination on the side of the passivation layer away from the porous composite structure thin strip; and The porous composite structure thin strip after fluorination was annealed, and the tin and lithium atoms inside the porous composite structure thin strip formed Li 22 Sn5, zinc atoms and lithium atoms form Li2Zn, Li 22 Sn5 and Li2Zn form a buffer region between the nanocrystalline and amorphous regions inside the porous composite thin strip, and the high-entropy lithium alloy material is obtained after annealing.

2. The method for preparing the high-entropy lithium alloy material as described in claim 1, characterized in that: Grinding metallic raw materials such as lithium, aluminum, magnesium, tin, and zinc into a mixed powder includes: Provides lithium, aluminum, magnesium, tin and zinc metal raw materials, pre-processes the metal raw materials into lithium, aluminum, magnesium, tin and zinc metal powders, wherein the lithium metal powder particle size ranges from 1 to 10 μm, and the aluminum, magnesium, tin and zinc metal powder particle size ranges from 10 to 50 nm, and the mass ratio of lithium, aluminum, magnesium, tin and zinc in the mixed powder is lithium:aluminum:magnesium:tin:zinc = (80~90% : 2~6% : 1~4% : 1~5% : 1~5%). Provide ball milling equipment. Preheat the ball milling equipment to 600-800℃ at a heating rate of 5-10℃ / min. After heating, place the metal powders of lithium, aluminum, magnesium, tin and zinc into the ball milling equipment and grind them for 4-8 hours at a stirring speed of 100-400rpm and a ball-to-material ratio of (15:1-20:1) to obtain mixed powder.

3. The method for preparing the high-entropy lithium alloy material as described in claim 1, characterized in that: The process involves heating the mixed powder to its melting temperature under a protective gas atmosphere, followed by adding a lithium compensator to form a melt, including: Provide a lithium compensator, wherein the lithium compensator is any one or more combinations of lithium nitride or lithium oxide; The mixed powder was heated from room temperature to a melting temperature of 1200-1300°C at a heating rate of 10-20°C / min under a protective gas atmosphere; After heating to the melting temperature, lithium compensator is added, and the lithium compensator and the molten mixed powder form a melt.

4. The method for preparing the high-entropy lithium alloy material as described in claim 1, characterized in that: Cooling of melts based on rapid quenching processes includes: Provide rapid quenching equipment, which is equipped with nozzles and single rollers spaced apart from the nozzles; The linear velocity of the single roller surface is controlled at 30±5 m / s, and the distance between the nozzle tip and the roller surface is controlled at 300±50 μm. The melt is sprayed through the nozzle onto the roller surface of the single roller under a protective gas atmosphere for cooling. The pressure of the protective gas atmosphere is 0.6±0.1 bar. After the melt comes into contact with the roller surface of the single roller, it is cooled from 1200~1300℃ to room temperature. During the cooling process, zinc atoms and tin atoms in the melt aggregate to one side of the melt to form a zinc / tin region. After cooling, a porous composite structure thin strip is obtained.

5. The method for preparing the high-entropy lithium alloy material as described in claim 1, characterized in that: Zinc atoms, magnesium atoms, and aluminum atoms react with oxygen to form a passivation layer on the surface of the porous composite strip, including: Zinc atoms react with oxygen to produce zinc oxide, magnesium atoms react with oxygen to produce magnesium oxide, and aluminum atoms react with oxygen to produce aluminum oxide. Zinc oxide, magnesium oxide, and aluminum oxide form a passivation layer on the surface of the porous composite strip.

6. The method for preparing the high-entropy lithium alloy material as described in claim 1, characterized in that: Fluorination treatment on the side of the passivation layer away from the porous composite structure thin strip includes: Argon and tetrafluoromethane gas are provided, and the argon and tetrafluoromethane gas are mixed in a flow ratio of (1:1) to (3:1) to form a mixed gas; The porous composite structure thin strip with the passivation layer is placed in a vacuum environment and a mixed gas is introduced. Then, it is subjected to plasma treatment for 30 to 45 minutes at a power of 150 to 250 W and a room temperature to 60°C to form a protective layer on the side of the passivation layer away from the porous composite structure thin strip.

7. The method for preparing the high-entropy lithium alloy material as described in claim 1, characterized in that: Annealing the fluorinated porous composite strip includes: The fluorinated porous composite thin strip was first heated to 150-200℃ at a rate of 1-5℃ / min, and held at that temperature for 30-60 minutes. During the first heating process, tin and lithium atoms inside the porous composite thin strip formed Li 22 Sn5, zinc atoms and lithium atoms form Li2Zn, Li 22 Sn5 and Li2Zn form a buffer region between the nanocrystalline and amorphous regions inside the porous composite structure thin strip; after the first heat preservation, the temperature is raised to 300~400℃ for the second time and kept for 15~30 minutes. After the second heat preservation, the material is cooled to room temperature at 0~5℃ / min to obtain a high-entropy lithium alloy material.

8. A high-entropy lithium alloy material, prepared by the preparation method of any one of claims 1 to 7, characterized in that: The high-entropy lithium alloy material includes a porous composite structure strip, a buffer region, a passivation layer, and a protective layer; the porous composite structure strip includes a nanocrystalline region and an amorphous region, and the buffer region is disposed between the nanocrystalline region and the amorphous region; the passivation layer is disposed on the outer surface of the porous composite structure strip and completely covers the porous composite structure strip, and the protective layer is disposed on the side of the passivation layer away from the porous composite structure strip.

9. A negative electrode material, characterized in that: It includes stacked current collectors and the high-entropy lithium alloy material as described in claim 8.

10. A battery, characterized in that: The battery includes a positive electrode material, an electrolyte, and a negative electrode material as claimed in claim 9.

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