A silicon-silver-indium ternary alloy thin film negative material for lithium ion batteries and a preparation method thereof

Abstract

The present application relates to the technical field of low-temperature negative electrode material preparation of lithium ion batteries, and particularly relates to a silicon-silver-indium ternary alloy thin film negative electrode material for lithium ion batteries and a preparation method thereof, the material comprises 40 at% to 99 at% of silicon, 0.1 at% to 30 at% of silver and 0.1 at% to 30 at% of indium in terms of atomic percentage. The preparation method comprises a melting metallurgy rolling process or a magnetron sputtering deposition process. In the ternary alloy system, the silver improves the electronic conductivity, the indium optimizes the lithium ion diffusion kinetics and the interface stability, and the synergistic effect of the two makes the material exhibit high capacity, high initial efficiency and good rate performance at normal temperature and low temperature. The material system has good compatibility with the above two differentiated preparation processes, and provides a solution for the large-scale and precision application of high-performance silicon-based thin film negative electrodes.

Description

Technical Field

[0001] This invention relates to the field of low-temperature anode material preparation technology for lithium-ion batteries, specifically to a silicon-silver-indium ternary alloy thin film anode material for lithium-ion batteries and its preparation method. Background Technology

[0002] On the one hand, silicon anode materials are considered key materials for improving battery energy density due to their high theoretical specific capacity (approximately 4200 mAh / g). However, they face serious challenges when used at low temperatures: slow ion diffusion and high interfacial impedance lead to a sharp decline in capacity and power performance. Currently, multi-element doping or composite strategies (such as introducing carbon, metal phases, etc.) are often used to improve the conductivity, interfacial stability, and slow down capacity decay. However, this strategy is still difficult to effectively solve the problem of low initial coulombic efficiency. The main reasons include: (1) the inactive components introduced by doping irreversibly consume lithium ions; (2) the SEI is uneven and unstable, and continues to be generated during cycling, constantly consuming active lithium and electrolyte. Under low temperature conditions, these irreversible processes are further aggravated, resulting in a more significant deterioration in initial efficiency and cycle performance.

[0003] On the other hand, thin-film anodes, due to their dense structure and short ion diffusion paths, have broad prospects in fields such as micro-batteries and flexible electronics. However, in existing technologies, the preparation of thin-film anodes is mostly limited to a single process (such as CVD, PVD, or electrodeposition), with the material system and process being highly tied, making it difficult to extend to low-cost, large-area preparation methods such as coating and rolling. Therefore, developing a thin-film anode system with universal composition and compatibility with multiple film-forming processes has become a key requirement for promoting its large-scale application.

[0004] To address the aforementioned issues, this invention proposes a bimetallic modification method that combines silver and indium, which exhibit good interactions with lithium, with silicon to prepare a silicon-silver-indium ternary composite material. Silver possesses excellent electrical conductivity and can optimize SEI properties, while indium interacts with lithium, exhibiting a low diffusion barrier and good reversibility, thus contributing to improved first-efficiency. Therefore, this material demonstrates excellent lithium storage performance under both room temperature and low-temperature conditions. Simultaneously, the strong compatibility among silicon, silver, and indium allows for thin-film fabrication using processes such as magnetron sputtering and melt smelting rolling, exhibiting strong process compatibility. This provides a crucial material foundation for the flexible implementation of metal thin-film anodes in various application scenarios and production scales. Summary of the Invention

[0005] The purpose of this invention is to provide a silicon-silver-indium ternary alloy thin film anode material for lithium-ion batteries and its preparation method. The material is composed of silicon, silver and indium and can be made into a thin film by melt metallurgical rolling or magnetron sputtering. It has high specific capacity, high initial coulombic efficiency and excellent low-temperature performance.

[0006] To achieve the above-mentioned technical objectives and effects, the present invention is implemented through the following technical solution: A silicon-silver-indium ternary alloy thin-film anode material for lithium-ion batteries, the material comprising silicon (Si), silver (Ag) and indium (In), wherein the silicon content is 40 at% to 99 at%, the silver content is 0.1 at% to 30 at%, and the indium content is 0.1 at% to 30 at%, and the material is a thin film.

[0007] Furthermore, on an atomic percentage basis, the silicon content is 60 at% to 90 at%, the silver content is 5 at% to 20 at%, and the indium content is 5 at% to 20 at.

[0008] On the other hand, the present invention proposes a method for preparing the silicon-silver-indium ternary alloy thin film anode material as described above, comprising the following steps: Provides silicon, silver, and indium sources; The silicon source, silver source, and indium source are used to form the ternary alloy thin film by molten metallurgical rolling or magnetron sputtering deposition.

[0009] Furthermore, the molten metallurgical rolling process includes: Solid raw materials of elemental silicon, elemental silver and elemental indium are smelted to form silicon-silver-indium ternary alloy ingots; The alloy ingot is rolled to obtain an alloy film with a thickness of 0.01 mm to 0.02 mm.

[0010] Furthermore, the melting is carried out in an inert or reducing atmosphere; and / or The rolling process is cold rolling.

[0011] Furthermore, the magnetron sputtering deposition process includes: In a vacuum environment, a silicon-silver-indium deposition layer is formed by using a target material including silicon and a target material including silver and indium as sputtering sources and depositing them together on a conductive substrate. The deposited layer is annealed to form the ternary alloy thin film.

[0012] Furthermore, the target material comprising silicon is a single silicon target, and the target material comprising silver and indium is a silver-indium alloy target.

[0013] Furthermore, the co-deposition is carried out in an argon or hydrogen-containing argon atmosphere; and / or The annealing process is carried out in an inert or reducing atmosphere, with an annealing temperature of 0°C to 300°C and an annealing time of 10 minutes to 6 hours.

[0014] Furthermore, the thickness of the ternary alloy film is from 200 nm to 6 μm.

[0015] On the other hand, the present invention proposes a lithium-ion battery, comprising a positive electrode, a negative electrode, an electrolyte, and a separator, wherein the negative electrode comprises the aforementioned silicon-silver-indium ternary alloy thin film negative electrode material.

[0016] The beneficial effects of this invention are: This invention fundamentally improves the carrier transport dynamics and interface stability of silicon-based anode materials through the synergistic modification of silver and indium, thereby achieving a balance between high specific capacity and high initial coulombic efficiency over a wide temperature range, especially at low temperatures. The highly conductive silver phase constructs a continuous electron conduction network within the silicon substrate, significantly reducing the ohmic impedance and charge transfer resistance of the electrode. Indium, with its low alloying barrier with lithium and high lithium-ion diffusion coefficient, acts as a rapid lithium-ion transport channel and buffer phase. The combined effect of these two phases not only enhances the overall conductivity and ion diffusion rate of the electrode but also helps induce the formation of a thin and stable solid electrolyte interface film. At low temperatures, this effectively suppresses the continuous decomposition of the electrolyte and the irreversible consumption of active lithium, thus significantly improving the initial efficiency while maintaining high capacity. Example data confirms that the ternary alloy film of this invention can still provide a reversible capacity of up to 725 mAh / g at -25°C and a 1C rate, with an initial efficiency generally exceeding 94%, far superior to the comparative silicon-silver binary system and pure silicon films.

[0017] The silicon-silver-indium ternary system described in this invention, based on its excellent metallurgical compatibility, achieves inherent compatibility with various film-forming processes. Silicon, silver, and indium can form a uniform alloy phase in either the molten or vapor-deposited state, allowing it to be fabricated into independent foils through bulk deformation processes such as melt smelting and plastic rolling, or to form thin films with good adhesion on various substrates through physical vapor deposition processes such as magnetron sputtering. This enables the material system to flexibly adapt to the needs of different application scenarios and production scales: the melt rolling route is suitable for low-cost, high-volume production of micron-scale thick-film electrodes; while the magnetron sputtering route meets the requirements for microelectronic device fabrication with nanometer-level precise control of film thickness and composition. This provides a crucial material foundation for silicon-based thin-film anodes to move from the laboratory to diversified industrial applications.

[0018] In the molten metallurgical rolling process, the purity of the alloy ingot is ensured by melting under an inert or reducing atmosphere. The subsequent cold rolling process, while achieving thinning, introduces grain refinement and defects, enhancing the diffusion capability of lithium ions. In the magnetron sputtering deposition process, the film composition is precisely adjusted within the range of 40 at% to 99 at% silicon, and 0.1 at% to 30 at% each of silver and indium by independently controlling the sputtering power of the silicon target and the silver-indium alloy target. The annealing treatment performed after deposition at 0°C to 300°C promotes the interdiffusion and alloying reaction between silicon, silver, and indium atoms, optimizing the crystallinity and phase composition of the film, directly improving its electrochemical reversibility and cycle stability. This ensures the reliability and repeatability of the material properties.

[0019] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments 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.

[0021] Figure 1 This is a photograph of the silicon-silver-indium ternary metal ingot obtained by melting and smelting in Example 1; Figure 2 This is a photograph of the silicon-silver-indium ternary metal thin film anode material prepared by melt smelting and rolling in Example 1; Figure 3 The charge-discharge curves of the silicon-silver-indium ternary metal thin film anode prepared by melt smelting and rolling in Example 1, at a current density of 0.1C in an environment of 25°C; Figure 4 The charge-discharge curves of the silicon-silver-indium ternary metal thin film anode prepared by melt smelting and rolling in Example 1, at 25°C and 1C current density. Figure 5 The charge-discharge curves of the silicon-silver-indium ternary metal thin film anode prepared by melt smelting and rolling in Example 1, at a current density of 0.1C in an environment of -25°C; Figure 6 The charge-discharge curve of the silicon-silver-indium ternary metal thin film anode prepared by melt smelting and rolling in Example 1 at a current density of 1C in an environment of -25°C; Figure 7 This is a photograph of the silicon-silver-indium ternary metal thin film anode material prepared by magnetron sputtering in Example 2. Figure 8The charge-discharge curves of the silicon-silver-indium ternary metal thin film anode material prepared by magnetron sputtering in Example 2 at 25°C and 0.1C current density are shown. Figure 9 The charge-discharge curves of the silicon-silver-indium ternary metal thin film anode material prepared by magnetron sputtering in Example 2 at 25°C and 1C current density are shown. Figure 10 The charge-discharge curves of the silicon-silver-indium ternary metal thin film anode material prepared by magnetron sputtering in Example 2 at a current density of 0.1C in an environment of -25°C. Figure 11 The charge-discharge curves of the silicon-silver-indium ternary metal thin film anode material prepared by magnetron sputtering in Example 2 at a current density of 1C in an environment of -25°C. Figure 12 For Comparative Example 1, the charge-discharge curves of the silicon-silver binary metal thin film anode prepared by melt smelting and rolling are shown at 25°C and 1C current density. Figure 13 For Comparative Example 1, the charge-discharge curves of the silicon-silver binary metal thin film anode prepared by melt smelting and rolling are shown at a current density of 1C in an environment of -25°C. Figure 14 The charge-discharge curves of the silicon metal thin film anode material prepared by magnetron sputtering in Comparative Example 2 at 25°C and 1C current density are shown. Figure 15 The charge-discharge curves of the silicon metal thin film anode material prepared by magnetron sputtering in Comparative Example 2 are shown at a current density of 1C in an environment of -25°C. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] The method for preparing silicon-silver-indium ternary metal thin film anode material by melt smelting and rolling as described in this embodiment includes the following specific steps: Elemental indium, elemental silicon, and elemental silver solids are placed in a graphite crucible. The three elemental solids are completely heated and melted using static heating or electromagnetic heating. After being held at the temperature, they are cooled to obtain silicon-silver-indium ternary metal ingots. By adjusting the proportion of elemental indium, elemental silicon, and elemental silver solids added, silicon-silver-indium ternary metal ingots with different elemental ratios can be prepared. The alloy ingot is placed in a rolling mill and extruded into a silicon-silver-indium ternary metal film.

[0024] The method for preparing silicon-silver-indium ternary metal thin film anode material by magnetron sputtering as described in this embodiment includes the following specific steps: Using a magnetron sputtering device, with a single silicon target and a silver-indium alloy target as sputtering sources for silicon and silver-indium elements respectively, and employing RF AC sputtering and DC sputtering methods respectively, silicon and silver-indium elements are co-deposited on the surface of a clean conductive substrate. By adjusting the power of the silicon target and the silver-indium alloy target, silicon-silver-indium ternary metal thin film anodes with different element ratios can be prepared. By performing appropriate annealing treatment on the deposited ternary metal thin film anode, the crystallinity of the metal film can be adjusted, thereby controlling its lithium storage performance.

[0025] In this embodiment, the purity of elemental indium, elemental silicon, and elemental silver is all between 80 at% and 100 at%. The heating atmosphere can be one or a mixture of several of air, nitrogen, argon, and hydrogen-argon. The holding time after melting is 10 minutes to 24 hours. In this embodiment, the method for obtaining ternary metal ingots by cooling the silicon-silver-indium melt is natural cooling. In this embodiment, the proportions of elemental indium, elemental silver, and elemental silicon added to the graphite crucible are (0.1at%~30at%), (0.1at%~30at%), and (40at%~99at%), respectively. In this embodiment, the cold-rolled ternary metal ingot is formed into a 0.5mm to 3mm metal sheet under a pressure of 2000 to 4000 kN / m, and then a 0.01 to 0.02mm lithium battery metal anode sheet is obtained by a double zero foil rolling process under a pressure of 1000 to 2000 kN / m.

[0026] In this embodiment, the purity of silicon in the elemental silicon target is 90 at% to 99.999 at%; the molar ratio of silver to indium in the silver-indium alloy target is between 8:1 and 1:8, and the total content of silver and indium accounts for 90 at% to 99.999 at% of the target material's molar content. In this embodiment, the sputtering frequency of the elemental silicon target is 13.56 MHz, and the sputtering power is 1-200 W / cm². 2 The DC sputtering power of the silver-indium alloy target is 0.1-20 W / cm². 2 .

[0027] In this embodiment, the molar contents of indium, silver and silicon in the thin film are (5at%~20at%), (5at%~20at%), and (60at%~90at%), respectively.

[0028] In this embodiment, the thickness of the ternary metal thin film is 200 nm to 6 μm.

[0029] In this embodiment, during sputtering, the gas pressure inside the magnetron sputtering chamber is maintained at 3 × 10⁻⁶. -4 Pa, the sputtering atmosphere is argon or a hydrogen-argon mixture (hydrogen content is 0.1at%-5at%); the sputtering substrate can be one of clean copper foil, titanium foil, nickel foil, or stainless steel foil.

[0030] In this embodiment, after sputtering deposition, the thin film annealing atmosphere is one of nitrogen, argon, hydrogen-argon, and helium, the heat treatment temperature is 0~300℃, and the heat treatment time is 10min~6h.

[0031] In this embodiment, the battery testing method for preparing silicon-silver-indium ternary metal thin-film anode materials by melt smelting and rolling employs a CR2032 battery testing device. The cut ternary metal thin film is used as the research electrode, lithium metal as the counter electrode, and CR2032 coin cells are assembled using 1 mol / L LiClO4-THF / DME (THF:DME mixed at a volume ratio of 1:1) as the electrolyte for testing. At 25°C, with current densities of 0.1C and 1C, the capacities are 2133~2246 mAh / g (affected by film composition ratio and film thickness) and 1572~1737 mAh / g (affected by film composition ratio and film thickness), respectively, with an initial efficiency of 80.8-94.1% (affected by film composition ratio and film thickness). At -25°C, with current densities of 0.1C and 1C, the capacities are 511~545 mAh / g (affected by film composition ratio and film thickness), respectively.

[0032] In this embodiment, the battery testing method for preparing silicon-silver-indium ternary metal thin film anode materials by magnetron sputtering employs a CR2032 battery testing device. A cut ternary metal thin film is used as the research electrode, lithium metal as the counter electrode, and CR2032 coin cells are assembled using 1 mol / L LiClO4-THF / DME (THF:DME mixed at a volume ratio of 1:1) as the electrolyte for testing. At 25°C, with current densities of 0.1C and 1C, the capacities are 2257~2745 mAh / g (affected by film composition ratio and film thickness) and 1689~1865 mAh / g (affected by film composition ratio and film thickness), respectively, with an initial efficiency of 84.2-94.5% (affected by film composition ratio and film thickness). At -25°C, with current densities of 0.1C and 1C, the capacities are 1625~1701 mAh / g (affected by film composition ratio and film thickness) and 667~725 mAh / g (affected by film composition ratio and film thickness), respectively.

[0033] This embodiment uses elemental silicon, elemental silver, and elemental indium as raw materials to synthesize a silicon-silver-indium ternary metal thin-film anode material through melt smelting and rolling. The method for preparing the silicon-silver-indium ternary metal thin-film anode material is carried out according to the following steps: S1: Solid elements of elemental silicon, elemental silver, and elemental indium are placed in a graphite crucible in the following proportions: silicon: 95 at%, silver: 2.5 at%, indium: 2.5 at%.

[0034] S2: Place the crucible containing the material into a resistance wire vacuum furnace, set the heating rate to 5 ℃ / min, heat to 1500 ℃, and hold for 12 h. Cool at room temperature to obtain ternary metal ingot material. Perform surface polishing on the metal ingot to remove surface slag inclusions, pores, and other defects.

[0035] S3: A ternary metal ingot is cold-rolled to form a 2mm metal sheet under a pressure of 3000 kN / m, and then a 0.02mm metal sheet is produced by a double zero foil rolling process under a pressure of 2000 kN / m.

[0036] S4: A CR2032 battery testing device was used. A cut ternary metal thin film was used as the research electrode, lithium metal as the counter electrode, and CR2032 coin cells were assembled using 1 mol / L LiClO4-THF / DME (THF:DME mixed at a volume ratio of 1:1) as the electrolyte for testing. Electrochemical performance was tested at 0.1C and 1C current densities at 25℃ and -25℃, respectively.

[0037] In this embodiment, the relevant test data is as follows: (1) Actual picture of silicon-silver-indium ternary metal ingots obtained by melting and smelting ( Figure 1 ); (2) Physical image of silicon-silver-indium ternary metal thin film anode material prepared by melt smelting and rolling ( Figure 2 ); (3) A silicon-silver-indium ternary metal thin film anode was prepared by melt smelting and rolling. In an environment of 25°C, the initial discharge capacity at a current density of 0.1C was 2302 mAh / g, and the initial efficiency was 91.5%. Figure 3 ); (4) A silicon-silver-indium ternary metal thin film anode was prepared by melt smelting and rolling. In an environment of 25°C, the initial discharge capacity at a current density of 1C was 1650mAh / g, and the initial efficiency was 93.8%. Figure 4 ); (5) A silicon-silver-indium ternary metal thin film anode was prepared by melt smelting and rolling. In an environment of -25°C, the initial discharge capacity at a current density of 0.1C was 1301mAh / g, and the initial efficiency was 89.6%. Figure 5 ); (6) A silicon-silver-indium ternary metal thin film anode was prepared by melt smelting and rolling. In an environment of -25°C, the initial discharge capacity at a current density of 1C was 552mAh / g, and the initial efficiency was 94.2%. Figure 6 ); Example 2 This embodiment uses silicon targets and silver-indium alloy targets as raw materials to synthesize silicon-silver-indium ternary metal thin film anode materials by magnetron sputtering. The method for preparing silicon-silver-indium ternary metal thin film anode materials is carried out according to the following steps: S1: Install the silicon target and the silver-indium target onto the AC target and the DC target respectively, and load the cleaned rough copper foil as the sputtering substrate onto the sample stage.

[0038] S2: Evacuate the chamber; the chamber pressure should be less than 3 × 10⁻⁶. -4 Pa.

[0039] S3: Introduce argon gas and control the chamber pressure to 2Pa, which serves as the working pressure; S4: Adjust the power of the silicon target and the silver-indium alloy target. The sputtering frequency of the single-material silicon target is 13.56 MHz, and the sputtering power is 50 W / cm². 2 The DC sputtering power of the silver-indium alloy target is 2W / cm. 2 The sputtering time was 5 hours, resulting in a ternary metal thin film with a thickness of 3 micrometers, a silicon content of 85 at%, a silver content of 10 at%, and an indium content of 5 at%.

[0040] S5: After sputtering deposition, the ternary metal thin film is heat-treated at 200℃ for 2 hours under an argon atmosphere.

[0041] S6: A CR2032 battery testing device was used. A cut ternary metal thin film was used as the research electrode, lithium metal as the counter electrode, and CR2032 coin cells were assembled using 1 mol / L LiClO4-THF / DME (THF:DME mixed at a volume ratio of 1:1) as the electrolyte for testing. Electrochemical performance was tested at 0.1C and 1C current densities at 25℃ and -25℃, respectively.

[0042] In this embodiment, the relevant test data is as follows: (1) Physical image of silicon-silver-indium ternary metal thin film anode material prepared by magnetron sputtering ( Figure 7 ); (2) A silicon-silver-indium ternary metal thin film anode material was prepared by magnetron sputtering. In an environment of 25°C, the initial discharge capacity at a current density of 0.1C was 2317mAh / g, and the initial efficiency was 89.9%. Figure 8 ); (3) A silicon-silver-indium ternary metal thin film anode material was prepared by magnetron sputtering. In an environment of 25°C, the initial discharge capacity at a current density of 1C was 1708 mAh / g, and the initial efficiency was 93.4%. Figure 9 ); (4) A silicon-silver-indium ternary metal thin film anode material was prepared by magnetron sputtering. In an environment of -25°C, the initial discharge capacity at a current density of 0.1C was 1687mAh / g, and the initial efficiency was 85.2%. Figure 10 ); (5) A silicon-silver-indium ternary metal thin film anode material was prepared by magnetron sputtering. In an environment of -25°C, the initial discharge capacity at a current density of 1C was 751mAh / g, and the initial efficiency was 94.8%. Figure 11 ); Example 3: Comparative Example 1 This embodiment uses elemental silicon and elemental silver as raw materials to synthesize a silicon-silver binary metal thin film anode material through a melt smelting and rolling process. The method for preparing the silicon-silver binary metal thin film anode material is carried out according to the following steps: S1: Place solid elements of silicon and silver in a graphite crucible, with a ratio of 95 at% silicon to 5 at% silver.

[0043] S2: Place the crucible containing the material into a tube furnace, set the heating rate to 5 ℃ / min, heat to 1500℃, and hold at that temperature for 12 h. Cool at room temperature to obtain silicon-silver binary metal ingot material.

[0044] S3: The silicon-silver binary metal ingot is cold-rolled, polished, and then formed into a 2mm metal sheet under a pressure of 3000 kN / m. Then, a 0.02mm lithium battery metal anode sheet is produced by a double zero foil rolling process under a pressure of 2000 kN / m.

[0045] S4: A CR2032 battery testing apparatus was used. A cut silicon-silver binary metal film was used as the research electrode, lithium metal as the counter electrode, and CR2032 coin cells were assembled using 1 mol / L LiClO4-THF / DME (THF:DME mixed at a volume ratio of 1:1) as the electrolyte for testing. Electrochemical performance was tested at a current density of 1C at both 25℃ and -25℃.

[0046] In this embodiment, the relevant test data is as follows: (1) A silicon-silver binary metal thin film anode material was obtained by melt smelting and rolling. In an environment of 25℃, the initial discharge capacity at a current density of 1C was 1538mAh / g, and the initial efficiency was 89.8%. Figure 12 ); (2) A silicon-silver binary metal thin film anode material was obtained by melt smelting and rolling. In an environment of -25°C, the 1C current density was 348 mAh / g, and the first-stage efficiency was 92.2%. Figure 12 ); Example 4: Comparative Example 2 This embodiment uses a silicon target as raw material to synthesize pure silicon thin-film anode material by magnetron sputtering. The method for preparing pure silicon thin-film anode material is as follows: S1: Install the silicon target onto the AC target, and load the cleaned copper foil as the sputtering substrate onto the sample stage.

[0047] S2: Evacuate the chamber; the chamber pressure should be less than 3 × 10⁻⁶. -4 Pa.

[0048] S3: Introduce gas and control the chamber pressure to 2Pa, which serves as the working pressure; S4: Adjust the power of the silicon target. The frequency of the sputtering RF for the elemental silicon target is 13.56 MHz, and the sputtering power is 50 W / cm². 2 The sputtering time was 6 hours, resulting in a pure silicon thin film material with a thickness of 3 micrometers.

[0049] S5: After sputtering deposition, the pure silicon thin film is heat-treated at 200℃ for 2 hours under an argon atmosphere.

[0050] S6: A CR2032 battery testing device was used. Pure silicon thin film material (cut from a substrate) was used as the research electrode, lithium metal as the counter electrode, and CR2032 coin cells were assembled using 1 mol / L LiClO4-THF / DME (THF:DME mixed at a volume ratio of 1:1) as the electrolyte. Electrochemical performance was tested at 0.1C and 1C current densities at 25℃ and -25℃, respectively.

[0051] In this embodiment, the relevant test data is as follows: (1) Pure silicon thin film anode material was prepared by magnetron sputtering. At 25°C, the current density at 1C was 2090 mAh / g, and the first-stage efficiency was 86.3%. Figure 14 ); (2) Pure silicon thin film anode material was prepared by magnetron sputtering. In an environment of -25°C, at a current density of 1C, the first efficiency was 91% (150 mAh / g). Figure 15 ); In summary, this invention proposes a silicon-silver-indium ternary alloy thin-film anode material for lithium-ion batteries and its preparation method. The material, by atomic percentage, comprises 40 at% to 99 at% silicon, 0.1 at% to 30 at% silver, and 0.1 at% to 30 at% indium. The preparation method includes fused metallurgical rolling or magnetron sputtering deposition. In this ternary alloy system, silver enhances electronic conductivity, while indium optimizes lithium-ion diffusion kinetics and interfacial stability. Their synergistic effect enables the material to exhibit high capacity, high initial efficiency, and good rate performance at both room temperature and low temperature. The material system of this invention exhibits good compatibility with both of the aforementioned differentiated preparation processes, providing a solution for the large-scale and precision application of high-performance silicon-based thin-film anodes.

[0052] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A silicon-silver-indium ternary alloy thin-film anode material for lithium-ion batteries, characterized in that, The material comprises silicon, silver and indium, wherein the silicon content is 40 at% to 99 at%, the silver content is 0.1 at% to 30 at%, and the indium content is 0.1 at% to 30 at, by atomic percentage.

2. The silicon-silver-indium ternary alloy thin-film anode material as described in claim 1, characterized in that, On an atomic percentage basis, the silicon content is 60 at% to 90 at%, the silver content is 5 at% to 20 at%, and the indium content is 5 at% to 20 at%.

3. A method for preparing the silicon-silver-indium ternary alloy thin film anode material as described in claim 1 or 2, characterized in that, Includes the following steps: Provides silicon, silver, and indium sources; The silicon source, silver source, and indium source are used to form the ternary alloy thin film by molten metallurgical rolling or magnetron sputtering deposition.

4. The method as described in claim 3, characterized in that, The molten metallurgical rolling process includes: Solid raw materials of elemental silicon, elemental silver and elemental indium are smelted to form silicon-silver-indium ternary alloy ingots; The alloy ingot is rolled to obtain an alloy film with a thickness of 0.01 mm to 0.02 mm.

5. The method as described in claim 4, characterized in that, The melting is carried out in an inert or reducing atmosphere; and / or The rolling process is cold rolling.

6. The method as described in claim 3, characterized in that, The magnetron sputtering deposition process includes: In a vacuum environment, a silicon-silver-indium deposition layer is formed by using a target material including silicon and a target material including silver and indium as sputtering sources and depositing them together on a conductive substrate. The deposited layer is annealed to form the ternary alloy thin film.

7. The method as described in claim 6, characterized in that, The target material including silicon is a single silicon target, and the target material including silver and indium is a silver-indium alloy target.

8. The method as described in claim 6 or 7, characterized in that, The co-deposition is carried out in an argon or hydrogen-containing argon atmosphere; and / or The annealing process is carried out in an inert or reducing atmosphere, with an annealing temperature of 0°C to 300°C and an annealing time of 10 minutes to 6 hours.

9. The method as described in claim 6, characterized in that, The thickness of the ternary alloy film is from 200 nm to 6 μm.

10. A lithium-ion battery, comprising a positive electrode, a negative electrode, an electrolyte, and a separator, characterized in that, The negative electrode comprises the silicon-silver-indium ternary alloy thin film negative electrode material as described in claim 1 or 2.

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