A silicon-antimony indium composite negative electrode material suitable for a low-temperature environment, and a preparation method and application thereof

Abstract

The application discloses a silicon-antimony indium composite negative electrode material suitable for a low-temperature environment, the composite negative electrode material is in a granular form, and comprises silicon particles and antimony indium particles; the antimony indium particles are uniformly distributed on the silicon particles; the mass percentage of the silicon is 60-90%, and the mass percentage of the antimony indium is 10-40%; the particle size of the silicon particles is 100-500 nm, the particle size of the antimony indium particles is 50-300 nm, and the overall particle size of the silicon-antimony indium composite negative electrode material is 0.5-5 mu m. The application innovatively combines a pendulum ball mill with a sound resonance dispersion technology, fully gives play to the advantages of high energy refinement of the pendulum ball mill and high-efficiency dispersion depolymerization of the sound resonance, realizes pre-combination of the two phases in a ball mill stage, and completes uniform dispersion as a 'finishing' step in a sound resonance stage; the two stages are in a cooperative action and indispensable. The composite negative electrode material can also maintain good electrochemical performance under a low-temperature condition, and has application potential in a low-temperature lithium ion battery.

Description

Technical Field

[0001] This invention belongs to the field of lithium battery technology, specifically, it relates to a silicon-indium antimonide composite anode material suitable for low-temperature environments, its preparation method and application. Background Technology

[0002] With the rapid development of new energy vehicles and portable electronic devices, the market has placed higher demands on the energy density of lithium-ion batteries. Traditional commercial graphite anodes, due to their low theoretical specific capacity (372 mAh / g), are no longer sufficient to meet the needs of next-generation high-energy-density batteries. Silicon (Si) materials, with their extremely high theoretical specific capacity (approximately 4200 mAh / g), moderate lithium insertion / extraction potential, and abundant resources, are considered one of the most promising next-generation anode materials. However, silicon anodes undergo significant volume expansion (>300%) during electrochemical cycling, which can easily lead to particle breakage and pulverization, loss of electrical contact between the active material and the current collector, and continuous rupture and regeneration of the solid electrolyte interphase (SEI) film, ultimately resulting in rapid capacity decay and a sharp reduction in cycle life. Furthermore, as an intrinsic semiconductor, silicon's low electronic conductivity also limits its rate performance, making it difficult to meet the requirements of fast-charging applications.

[0003] On the other hand, the performance degradation of lithium-ion batteries at low temperatures (such as -20°C and below) is a key bottleneck restricting their widespread application in cold regions and high-altitude environments. At low temperatures, the electrolyte viscosity increases, the diffusion rate of lithium ions in the electrode materials and electrolyte decreases significantly, and the charge transfer impedance increases, leading to a substantial decrease in battery capacity and a deterioration in rate performance. For silicon anodes, the solid-phase diffusion coefficient of lithium ions further decreases at low temperatures, limiting the kinetics of lithium intercalation reactions; simultaneously, the stress caused by the volume expansion of silicon at low temperatures is more easily concentrated, making particle pulverization and unstable SEI film growth problems more prominent. Therefore, developing silicon-based composite anode materials that can maintain good conductive network and structural stability at low temperatures is of significant practical importance.

[0004] Nanostructuring silicon and combining it with a highly conductive matrix is ​​an effective strategy to improve its electrochemical performance. Nanostructuring can shorten the diffusion path of lithium ions and effectively release the stress caused by volume changes; while combining it with a second phase can construct a stable conductive network and structural framework. For example, combining silicon with metals or alloys (such as Sn, Sb, Ag, etc.) through high-energy ball milling has been proven to improve the overall structural stability of the electrode. Indium antimonide (InSb) is a III-V compound semiconductor with a high theoretical specific capacity (approximately 660 mAh / g) and good electronic conductivity (electron mobility approximately 77,000 cm² / V·s). Combining silicon with a small amount of indium antimonide, utilizing the high conductivity of InSb to construct a conductive pathway, and simultaneously using its relatively good ductility to buffer the volume effect of silicon, is a feasible modification approach. However, InSb itself also undergoes certain volume changes during cycling, so its content needs to be precisely controlled to achieve a balance between improving conductivity and contributing capacity.

[0005] Traditional high-energy ball milling processes (such as planetary ball milling and oscillating ball milling) can achieve particle refinement and initial composite formation in the preparation of silicon-based composite materials, but they typically face the following problems: nanoparticles re-agglomerate due to their high surface energy, forming secondary particles; the difference in physical properties between active materials and modifying components leads to uneven mixing; prolonged high-energy ball milling can easily introduce impurities generated by wear of the grinding balls and the jar; in addition, excessive ball milling may damage the crystal structure of the material and introduce too many defects. Especially for material systems such as silicon and indium antimonide, which have significant differences in hardness and ductility, a single ball milling process is insufficient to achieve particle refinement while ensuring uniform dispersion and close contact between the two phases. Therefore, there is an urgent need to develop a novel preparation process that can effectively solve particle agglomeration, achieve uniform composite formation of multiphase materials, and has high process controllability. Summary of the Invention

[0006] The purpose of this application is to overcome the above-mentioned shortcomings of the prior art and provide a silicon-indium antimonide composite anode material suitable for low-temperature environments. By introducing indium antimonide and synergistic processing of ball milling and acoustic resonance dispersion, secondary uniform dispersion of silicon and indium antimonide particles at the microscale is achieved, effectively solving the problem of particle agglomeration.

[0007] To achieve the above-mentioned objectives, this application provides a silicon-indium antimonide composite anode material suitable for low-temperature environments. The composite anode material is granular, comprising silicon particles and indium antimonide particles, wherein the indium antimonide particles are uniformly distributed on the silicon particles; wherein the mass percentage of silicon is 60%~90%, and the mass percentage of indium antimonide is 10%~40%; the particle size of the silicon particles is 100-500 nm, the particle size of the indium antimonide particles is 50-300 nm, and the overall particle size of the silicon-indium antimonide composite anode material is 0.5-5 μm.

[0008] The present invention, through the introduction of indium antimonide (InSb), has the following potential advantages under low-temperature conditions: the high electronic conductivity of InSb (electron mobility of approximately 77,000 cm² / V·s) can effectively reduce the charge transfer impedance of the electrode at low temperatures, compensating for the kinetic limitations caused by the decrease in lithium-ion diffusion rate; the uniform distribution of InSb in the silicon substrate achieved by acoustic resonance dispersion ensures the integrity of the conductive network at low temperatures; at the same time, the ductility of InSb can provide a buffer under low-temperature volume expansion stress, reducing particle pulverization.

[0009] This invention also provides a method for preparing the silicon-indium antimonide composite anode material suitable for low-temperature environments, comprising the following steps: S1. After mixing silicon powder and indium antimonide powder, place them in a vibrating ball mill and ball mill them under an inert atmosphere to obtain silicon-indium antimonide mixed powder; S2. Transfer the mixed powder obtained in step S1 to an acoustic resonance device, add a dispersant as a dispersion medium, start the acoustic resonance device for secondary dispersion treatment, and after drying, the silicon-indium antimonide composite anode material is obtained.

[0010] This invention employs a synergistic processing technique combining "oscillating ball milling + acoustic resonance dispersion." First, the high energy input of oscillating ball milling is used to initially refine and pre-composite micron-sized silicon and indium antimonide. Then, acoustic resonance technology, generated in anhydrous ethanol, effectively breaks down the nanoparticle agglomerates formed after ball milling, achieving secondary uniform dispersion of silicon and indium antimonide particles at the microscale. The core advantage of this synergistic process lies in the fact that the oscillating ball milling stage focuses on mechanical energy input to achieve particle breakage and initial mixing, while the acoustic resonance stage utilizes the shear force and cavitation effect generated by low-frequency, high-acceleration vibration in the liquid medium to efficiently deagglomerate the agglomerates without damaging the material's structure. The resulting composite anode material exhibits both high specific capacity and excellent cycle stability.

[0011] Preferably, in S1, the particle size range of the silicon powder is 1μm to 5μm, and the particle size range of the indium antimonide powder is 1μm to 10μm. The silicon powder (1μm to 5μm) and the indium antimonide powder (1μm to 10μm) are at similar micron-scales, making them less prone to severe "large particles encapsulating small particles" or "small particle agglomeration" during ball milling. This facilitates their uniform distribution at the microscale, thereby constructing a continuous conductive network. Simultaneously, it avoids the operational difficulties caused by excessively fine raw materials and helps shorten the ball milling time.

[0012] Preferably, in step S1, the ball mill speed is 800-1200 rpm, the ball milling time is 2-24 hours, and the mass ratio of grinding balls to mixed powder during the ball milling process is 15:1-50:1; the inert atmosphere is an argon atmosphere or a nitrogen atmosphere. Optionally, the grinding balls are made of zirconium oxide, and two specifications with diameters of 5 mm and 10 mm are used in a mass ratio of 2:1 to improve the ball milling efficiency.

[0013] Setting the milling speed within the medium-high range of 800-1200 rpm provides sufficient mechanical energy to effectively deform and break up silicon and InSb particles without causing severe lattice distortion or excessive amorphization due to excessively high speeds (>1500 rpm). Silicon is a hard and brittle material, while InSb is relatively soft and ductile. The 800-1200 rpm range allows InSb to undergo plastic deformation under impact and coat the surface of silicon particles, which is beneficial for building a continuous conductive network. An inert atmosphere prevents powder oxidation during ball milling. A high ball-to-powder ratio means that a large number of grinding balls impact the powder at high frequency per unit time, which helps to quickly break down the differences in physical properties (hardness, ductility) between silicon and InSb particles, promoting uniform mixing of the two materials at the nanoscale and preventing the formation of "silicon agglomeration zones" or "InSb isolation zones." In addition, with a ball-to-powder ratio as high as 50:1, the grinding balls provide more thorough impact coverage on the powder, allowing the relatively soft InSb to be more effectively cold-welded to the surface of silicon particles, forming a conductive "coating" or "network skeleton," which is crucial for improving electronic conductivity and buffering silicon expansion.

[0014] In some embodiments of the present invention, the inner wall of the ball mill may be pre-coated with a polytetrafluoroethylene (PTFE) lining or made of yttrium-stabilized zirconium oxide (Y-PSZ) material to reduce the introduction of metallic impurities (such as Fe and Cr) during the ball milling process.

[0015] Preferably, in step S2, the dispersant includes one or more of anhydrous ethanol, isopropanol, n-hexane, polyvinylpyrrolidone solution, and stearic acid solution, and its addition amount is 15% to 200% of the total mass of the mixed powder. This dosage range can reduce the energy consumption of subsequent drying while ensuring sufficient wetting and dispersion effects.

[0016] Preferably, in step S2, the operating frequency of the acoustic resonance device is 40Hz-70Hz, the acceleration is 30g-80g, and the processing time is 10min-60min. These parameter settings enable contactless, non-damaging, efficient deagglomeration and uniform dispersion of Si / InSb composite slurry, particularly suitable for two-component systems with high solid content and large density differences. Compared to traditional ultrasonic or stirring processes, this significantly shortens the time, avoids impurity introduction, protects the intrinsic structure of the material, and ensures the consistency of electrode preparation and the stability of electrochemical performance. Compared to a single ball milling process, by introducing an acoustic resonance dispersion step, efficient deagglomeration and uniform mixing of composite powders can be achieved with lower energy consumption, avoiding the risks of introducing impurities and damaging the material structure associated with traditional long-duration high-energy ball milling. The processing time of the acoustic resonance device is typically only tens of minutes, significantly shorter than the several hours or even tens of hours required by traditional wet ball milling or stirred milling.

[0017] In some embodiments of the present invention, for powders with severe agglomeration after ball milling, two acoustic resonance treatments can be performed: after the first treatment, the powder is allowed to stand for 5 minutes, and then a small amount of dispersant (approximately 10% to 20% of the initial amount) is added for a second treatment, with the treatment time halved. This operation can further improve the dispersion uniformity.

[0018] Preferably, in step S2, the drying process includes taking out the material and vacuum drying it at 60°C to 80°C to remove the dispersion medium, thereby obtaining the silicon-indium antimonide composite anode material. Further optionally, after complete drying, the mixed powder is ground uniformly to achieve a silicon particle size of 100-500 nm, an indium antimonide particle size of 50-300 nm, and an overall particle size of 0.5-5 μm for the silicon-indium antimonide composite anode material. While preserving the uniform mixing state resulting from acoustic resonance dispersion, gentle vacuum drying avoids hard agglomeration, and moderate grinding precisely controls the final particle size, simultaneously optimizing electrochemical performance at three scales (Si, InSb, and composite particles): nano-sized Si shortens the Li... + The process buffers expansion, and sub-nanometer InSb constructs a highly conductive network and enhances stress release. The overall particle size of 0.5-5μm balances coating processability. These three factors work synergistically to achieve a comprehensive balance of high capacity, long cycling, excellent rate capability, and low-temperature performance, while maintaining controllable process costs and strong industrial compatibility.

[0019] The present invention also provides a negative electrode for a lithium-ion battery, the negative electrode comprising the aforementioned silicon-indium antimonide composite negative electrode material, a conductive agent and a binder, wherein the mass ratio of the silicon-indium antimonide composite negative electrode material, the conductive agent and the binder is (7~8): (1~2): 1.

[0020] The present invention also provides the application of the above-mentioned silicon-indium antimonide composite anode material and preparation method in lithium batteries, especially suitable for lithium batteries to operate in low temperature environments from -40°C to 0°C.

[0021] Compared with the prior art, this application has the following technical effects: 1. This invention innovatively combines oscillating ball milling with acoustic resonance dispersion technology, fully leveraging the advantages of high-energy refining by oscillating ball milling and efficient dispersion and deagglomeration by acoustic resonance. This successfully solves the industry pain point of easy agglomeration and uneven dispersion during the composite process of silicon and indium antimonide. The ball milling stage achieves pre-composite properties of the two phases, while the acoustic resonance stage serves as a "finishing" step to achieve uniform dispersion. Both stages work synergistically and are indispensable.

[0022] 2. In the silicon-indium antimonide composite anode material prepared by this invention, indium antimonide particles are uniformly dispersed in the silicon matrix. This not only constructs a good three-dimensional conductive network, effectively reducing the charge transfer impedance of the electrode, but also effectively buffers the volume expansion of silicon during lithium insertion / extraction, thereby significantly improving the cycle stability and rate performance of the composite electrode. Experimental data show that after 100 cycles at a current density of 1.0 A / g, the capacity retention rate can reach over 76%, which is far superior to that of pure silicon anodes (approximately 28.5%) and composite materials prepared by a single ball milling process (approximately 29.0%). At a high rate of 6.0 A / g, the reversible capacity can still be maintained at approximately 1048.76 mAh / g. Based on the highly conductive network and uniformly dispersed structure of InSb, it is foreseeable that this composite material can maintain good electrochemical performance under low-temperature conditions, and has the potential for application in low-temperature lithium-ion batteries.

[0023] 3. The preparation method of this invention is simple to operate, the dispersion medium is easily and completely removed by vacuum drying, and it is environmentally friendly, without introducing harmful impurities. It is suitable for the industrial-scale mass production of high-quality silicon-based composite anode materials. The entire process consists of only two main steps, and the equipment used is all commercially available standard equipment, demonstrating good prospects for industrialization. Attached Figure Description

[0024] Figure 1 The image shows the XRD pattern of the silicon-indium antimonide composite anode material prepared in Example 1 of this invention. Figure 2 This is a SEM image of the silicon-indium antimonide composite anode material prepared in Example 1 of this invention; Figure 3 The first three charge-discharge curves of the lithium-ion half-cell with the silicon-indium antimonide composite anode material prepared in Example 1 of the present invention at 30°C. Figure 4 The graph shows the cycle performance of a lithium-ion half-cell of the silicon-indium antimonide composite anode material prepared in Example 1 of the present invention at 30°C. Figure 5The rate performance curve of the lithium-ion half-cell of the silicon-indium antimonide composite anode material prepared in Example 1 of the present invention at 30°C. Figure 6 The first three charge-discharge curves of the lithium-ion half-cell with the silicon-indium antimonide composite anode material prepared in Example 2 of the present invention at 30°C. Figure 7 The graph shows the cycling performance of the lithium-ion half-cell of the silicon-indium antimonide composite anode material prepared in Example 2 of this invention at 30°C. Figure 8 The rate performance curve of the lithium-ion half-cell of the silicon-indium antimonide composite anode material prepared in Example 2 of the present invention at 30°C. Figure 9 The graph shows the cycling performance of a lithium-ion half-cell using the pure silicon anode material prepared in Comparative Example 1 of this invention at 30°C. Figure 10 The graph shows the cycling performance of the lithium-ion half-cell of the silicon-indium antimonide composite anode material prepared in Comparative Example 2 of this invention at 30°C. Figure 11 The graph shows the cycling performance of the lithium-ion half-cell of the silicon-indium antimonide composite anode material prepared in Comparative Example 3 of this invention at 30°C. Figure 12 The first three charge-discharge curves of the Si-InSb-0-LT lithium-ion half-cell. Figure 13 The first three charge-discharge curves of the Si-InSb-3-LT lithium-ion half-cell. Figure 14 The graph shows the long-cycle test results of the lithium-ion half-cell Si-InSb-0-LT at -10℃. Figure 15 This is a graph showing the long-cycle test results of the lithium-ion half-cell Si-InSb-3-LT at -10℃. Detailed Implementation

[0025] To enable those skilled in the art to better understand the present invention, the present invention will now be further described in conjunction with specific embodiments.

[0026] In the following description, the embodiments of this application are for illustrative purposes and not for limiting purposes, so as to provide a thorough understanding of the embodiments. However, those skilled in the art will understand that the embodiments of this application can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known preparation methods have been omitted so as not to obscure the description of the embodiments of this application with unnecessary details. Unless otherwise specified, the raw materials used in the following embodiments are all commercially available.

[0027] It should also be understood that the terms "comprising," "including," "having," and their variations all mean "including but not limited to," unless otherwise specifically emphasized. Only content related to the inventive points is described here; other details can be obtained from related technologies and will not be elaborated further here. The following embodiments merely illustrate several implementations of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

[0028] The specific implementation method is as follows: Example 1: The preparation of a silicon-indium antimonide composite anode material includes the following steps: S1. In an argon-protected glove box (water and oxygen content <0.1ppm), weigh 2.8g of micron-sized silicon powder with a particle size range of 1μm to 5μm (purity 99.9%) and 1.2g of indium antimonide powder with a particle size range of 1μm to 10μm (purity 99.9%) (silicon to indium antimonide mass ratio 7:3). Place them together in a 0.2L zirconia ball mill jar and ball mill using the vibratory ball milling method. The mass ratio of grinding balls to mixed powder is 50:1, and the milling time is 6 hours. The specific method of vibratory ball milling is as follows: ① Load grinding balls and the mixed powder in the ball mill jar. The grinding balls are made of zirconium oxide and come in two sizes with diameters of 5mm and 10mm, used in a mass ratio of 2:1 to improve the ball milling efficiency. ② The sealing process of the ball mill jar is carried out in a glove box filled with argon gas. The pressure in the glove box is 1 atmosphere to ensure that the inside of the jar is an oxygen-free environment. ③ Connect the power supply to the vibrating ball mill, set the ball milling mode to a single working time of 15 minutes, a rest time of 15 minutes, a total running time of 12 hours, and an effective ball milling time of 6 hours; fix the grinding jar on the vibrating ball mill frame and begin ball milling, with the motor speed at 1000 rpm. Using an intermittent operation mode avoids overheating of the jar caused by continuous long-term ball milling, which helps protect the material structure.

[0029] S2. Transfer about 4.0 g of all the obtained mixed powders into a polytetrafluoroethylene container equipped with an acoustic resonance device, and add 4.0 g of absolute ethanol as a dispersion medium. After sealing the container, fix it on the resonance platform of an acoustic resonance mixing device (such as LabRAM or a device with equivalent functions). Set the operating frequency of the device to 60 Hz, the acceleration to 50 g, and the processing time to 20 min. After the processing is completed, transfer the slurry to a vacuum drying oven and vacuum dry it at 80 °C for 8 h (vacuum degree ≤ -0.1 MPa). After complete drying, grind it evenly to obtain the silicon-indium antimonide composite anode material of this example, denoted as Si-InSb-3 (Si:InSb = 7:3).

[0030] The XRD pattern of the anode material prepared in this example is shown in Figure 1 . The XRD pattern shows that the characteristic diffraction peaks of crystalline silicon and indium antimonide coexist in the material, and there are no obvious oxidation peaks or other impurity peaks, indicating that the material is not oxidized or impurities are introduced during the preparation process.

[0031] The SEM image of the anode material prepared in this example is shown in Figure 2 , as shown in the figure, the ball-milled InSb particles are evenly distributed on the Si matrix, and there is no obvious agglomeration phenomenon. The two phases form a tight interfacial contact. This uniform dispersion structure is beneficial to fully exert the high-capacity characteristics of the Si material and at the same time use InSb to construct a continuous conductive network.

[0032] Assembly and electrochemical performance test of coin cells: Mix the prepared Si-InSb-3 composite material, conductive agent Super-P, and binder sodium carboxymethyl cellulose (CMC) evenly in deionized water according to a mass ratio of 8:1:1, and prepare a uniform electrode slurry by stirring with a high-speed stirring defoamer at a rotation speed of 2000 rpm for 30 min. Coat the slurry evenly on a battery-grade copper foil with a coating thickness of 200 μm, and then transfer it to a vacuum drying oven and dry it at 80 °C for 12 h. After drying, cut it into a circular sheet with a diameter of 12 mm as the working electrode, and the active material loading is about 1.5 mg / cm².

[0033] In a high-purity argon glove box (water and oxygen content both <0.01ppm), a CR2032 coin cell was assembled using a lithium metal sheet as the counter electrode, a Celgard 2400 polypropylene membrane as the separator, and a solution of 1 mol / L lithium hexafluorophosphate (LiPF6) dissolved in ethylene carbonate / diethyl carbonate (volume ratio 1:2) with 10 wt% fluoroethylene carbonate (FEC) as the electrolyte. The addition of FEC helps form a stable SEI membrane and improves cycle performance. Constant current charge-discharge tests were performed on a LAND CT2001A battery testing system with a voltage window of 0.01V–1.5V (vs. Li / Li). + The test temperature was constant at 30℃.

[0034] from Figure 2 The SEM images clearly show that after the combined treatment of ball milling and acoustic resonance, the particle size of the material was significantly refined, and the two phases were evenly distributed without obvious large agglomerates, indicating that silicon and indium antimonide achieved good dispersion and recombination. This structural feature provides the foundation for excellent electrochemical performance.

[0035] The charge-discharge curves obtained from the first three cycles of the test are shown below. Figure 3 As shown in the figure, the initial discharge (lithium insertion) curve exhibits a typical silicon lithium insertion plateau below approximately 0.1V, while the initial charge (lithium removal) curve displays characteristic lithium removal behavior of silicon and indium antimonide. The anode material prepared in this embodiment was first activated at 0.2 A / g for 3 cycles at 30°C to form a stable SEI film, followed by long-cycle testing at a current density of 1.0 A / g. The initial reversible capacity was 2048.3 mAh / g, and the initial coulombic efficiency was 83.5%. After 100 cycles at 1.0 A / g, the reversible capacity decreased from 1781.5 mAh / g to 1361.1 mAh / g, with a capacity retention of 76%. Figure 4 Compared to Comparative Example 1 and Comparative Example 2, the cycle stability was significantly improved.

[0036] Figure 5 This is the rate performance curve of the fabricated coin cell. For example... Figure 5 As shown, the prepared anode material exhibits stable specific capacity contributions at different current densities of 0.2, 0.5, 1.0, 2.0, 4.0, and 6.0 A / g. Specifically, the reversible capacity is approximately 2100 mAh / g at 0.2 A / g, approximately 1910.9 mAh / g at 1.0 A / g, and even at a high current density of 6.0 A / g, the reversible capacity remains as high as approximately 1048.76 mAh / g, with a capacity retention rate (relative to 0.2 A / g) of approximately 50.9%. This fully demonstrates that the introduction of InSb effectively improves the electronic conductivity of the material, enabling it to maintain a high capacity output even at high rates.

[0037] Example 2: The preparation of a silicon-indium antimonide composite anode material includes the following steps: The preparation steps in this embodiment are basically the same as those in Example 1, except that the mass ratio of micron-sized silicon powder to indium antimonide powder in step S1 is 6:4, i.e., 2.4g of silicon powder and 1.6g of indium antimonide (scaled up to a total of 4.0g). The resulting material is denoted as Si-InSb-4 (Si:InSb=6:4).

[0038] Assembly and electrochemical performance testing of coin cells: The electrode preparation and battery assembly testing methods are the same as in Example 1.

[0039] Figure 6 The data includes the charge-discharge curves of the Si-InSb-4 anode prepared in this embodiment for the first three cycles at a current density of 0.2 A / g. The test results show that the initial reversible specific capacity of this composite material is 1581.2 mAh / g, and the initial coulombic efficiency is 81.75%. At a current density of 1.0 A / g, the initial capacity is 1325.1 mAh / g, and after 100 cycles, the reversible capacity is 1093.2 mAh / g, with a capacity retention of 82.5%. (See attached data). Figure 7 Compared to Example 1, the capacity retention increased from 76% to 82.5%, an improvement of approximately 6.5 percentage points, while the initial reversible capacity decreased from 2048.3 mAh / g to 1581.2 mAh / g due to the increased InSb content (InSb's theoretical capacity is lower than Si). This indicates that appropriately increasing the indium antimonide content, although sacrificing some initial capacity, can more effectively buffer the volume expansion of silicon, thereby further improving long-term cycling stability. In practical applications, the Si to InSb ratio can be optimized according to different priorities for energy density and cycle life.

[0040] Figure 8 This is the rate performance curve of the fabricated coin cell. For example... Figure 8 As shown, the prepared anode material exhibits stable specific capacity contribution at different current densities, with a reversible capacity of approximately 818.4 mAh / g even at 6.0 A / g. Notably, when the rate gradually decreases from 6.0 A / g to 2.0, 1.0, and 0.2 A / g, the battery capacity recovers to the levels of the previous corresponding rate, indicating that the electrode structure was not severely damaged after experiencing a high current surge. This further confirms that the addition of InSb is beneficial for improving the structural stability of the electrode under high current charge and discharge conditions, which is of great significance for fast charging applications.

[0041] Example 3: The preparation of a silicon-indium antimonide composite anode material includes the following steps: S1. In an argon-filled glove box (water and oxygen <0.1ppm), weigh 3.6g of 1-5μm micron-sized silicon powder and 0.4g of 1-10μm-sized indium antimonide powder (silicon to indium antimonide mass ratio 9:1) and load them into a 0.2L zirconia ball mill jar. The mass ratio of grinding balls to mixed powder is 30:1. The grinding balls are made of zirconia, with 5mm and 10mm balls mixed in a 2:1 mass ratio. The ball mill parameters are: 20min single run, 10min rest, total running time 24h (12h effective grinding), motor speed 800rpm. The ball mill jar is sealed in a glove box at 1 atmosphere.

[0042] S2. Transfer all the ball-milled mixed powder (approximately 4.0 g) to a polytetrafluoroethylene container in an acoustic resonance apparatus, and add 6.0 g of isopropanol as a dispersant (the amount added is 150% of the powder mass). After sealing, fix it on the resonance platform, set the frequency to 40 Hz and the acceleration to 30 g, and process for 60 min. After completion, transfer the slurry to a vacuum drying oven and dry at 60℃ for 12 h (vacuum degree ≤ -0.1 MPa). After complete drying, grind it uniformly to obtain the silicon-indium antimonide composite anode material, denoted as Si-InSb-1. The silicon particle size in the product is 100-500 nm, the indium antimonide particle size is 50-300 nm, and the overall size of the composite particles is 0.5-5 μm.

[0043] Example 4: The preparation of a silicon-indium antimonide composite anode material includes the following steps: S1. In an argon-filled glove box (water and oxygen <0.1ppm), weigh 2.4g of 1-5μm micron-sized silicon powder and 1.6g of 1-10μm-sized indium antimonide powder (silicon to indium antimonide mass ratio 6:4) and load them into a 0.2L zirconia ball mill jar. The mass ratio of grinding balls to mixed powder is 50:1, and the grinding ball sizes of 5mm and 10mm are matched at a mass ratio of 2:1. Vibratory ball milling: 10min per cycle, 5min rest, total running time 3h (2h effective ball milling), motor speed 1200rpm. The jar is sealed in a glove box during the process.

[0044] S2. Take all the ball-milled powder (approximately 4.0 g), add 0.8 g of n-hexane and 0.8 g of anhydrous ethanol as a dispersant (total addition 1.6 g, 40% of the powder mass). Place in an acoustic resonance apparatus, set the frequency to 70 Hz and the acceleration to 80 g, and process for 10 min. Then transfer to a vacuum drying oven and dry at 80℃ for 6 h (vacuum degree ≤ -0.1 MPa). After drying, grind evenly to obtain a silicon-indium antimonide composite anode material, denoted as Si-InSb-4. The product particle size meets the requirements: silicon particles 100-500 nm, indium antimonide particles 50-300 nm, and the overall composite material 0.5-5 μm.

[0045] Example 5: The preparation of a silicon-indium antimonide composite anode material includes the following steps: S1. In a nitrogen glove box (water and oxygen <0.1ppm), weigh 3.2g of 1-5μm micron-sized silicon powder and 0.8g of 1-10μm indium antimonide powder (silicon to indium antimonide mass ratio 8:2), and load them into a 0.2L zirconia ball mill jar. The mass ratio of grinding balls to mixed powder is 40:1, and the grinding balls are zirconia with a 5mm to 10mm mass ratio of 2:1. Vibratory ball milling: 15min per cycle, 15min rest, total running time 16h (8h effective ball milling), motor speed 1000rpm. The jar is sealed in a glove box.

[0046] S2. Take all the ball-milled powder (approximately 4.0 g) and add 2.0 g of a 2% (w / w) polyvinylpyrrolidone (PVP) ethanol solution as a dispersion medium (PVP acts as an auxiliary dispersant, and the amount added is 50% of the powder mass). Place it in an acoustic resonance apparatus, set the frequency to 60 Hz and the acceleration to 50 g, and process for 30 min. After completion, transfer the slurry to a vacuum drying oven and dry at 70℃ for 10 h (vacuum degree ≤ -0.1 MPa). After complete drying, grind it uniformly to obtain a silicon-indium antimonide composite anode material, denoted as Si-InSb-2. The sizes of silicon particles, indium antimonide particles, and composite particles in the product all meet the scope of the claims.

[0047] Example 6: The preparation of a silicon-indium antimonide composite anode material includes the following steps: S1. In an argon-filled glove box (water and oxygen <0.1ppm), weigh 2.8g of 1-5μm micron-sized silicon powder and 1.2g of 1-10μm-sized indium antimonide powder (silicon to indium antimonide mass ratio 7:3) and load them into a 0.2L zirconia ball mill jar. The mass ratio of grinding balls to mixed powder is 20:1, and the grinding ball sizes of 5mm and 10mm are matched in a mass ratio of 2:1. Vibratory ball milling: 30min per cycle, 15min rest, total running time 36h (effective ball milling 24h), motor speed 900rpm. The jar is sealed in the glove box.

[0048] S2. Transfer all ball-milled powder (approximately 4.0 g) to an acoustic resonance container, and add 4.0 g of a 1% (w / w) stearic acid ethanol solution as a dispersion medium (stearic acid serves as a surface modifier, and the amount added is 100% of the powder mass). Acoustic resonance parameters: frequency 55 Hz, acceleration 65 g, treatment time 40 min. Then transfer to a vacuum drying oven and dry at 75℃ for 9 h (vacuum degree ≤ -0.1 MPa). After drying, grind evenly to obtain a silicon-indium antimonide composite anode material, denoted as Si-InSb-3-long. The silicon particle size in the product is 100-500 nm, the indium antimonide particle size is 50-300 nm, and the overall size of the composite particles is 0.5-5 μm.

[0049] Comparative Example 1: Preparation and testing of pure silicon anode materials: The preparation steps for this comparative example are the same as those described in step S1 of Example 1, but indium antimonide powder is not added. Only 4.0 g of pure micron-sized silicon powder is ball-milled for 6 hours. The ball-milled product is not subjected to acoustic resonance treatment and is directly dried to obtain pure silicon anode material.

[0050] The electrode preparation and battery assembly testing methods are the same as in Example 1. Figure 9 The results include the cycling performance curves of the comparative example. The results show that the initial reversible specific capacity of the pure silicon anode is 2885.5 mAh / g, significantly higher than that of the InSb-containing composite material. However, the capacity decays extremely rapidly; after 50 cycles, the capacity drops to approximately 1491.4 mAh / g. At a current density of 1.0 A / g, the initial capacity is 2388.83 mAh / g, but after 100 cycles, the capacity drops to 713.07 mAh / g, with a capacity retention of only 29.8%. The main reason for the rapid capacity decay is that the large volume change of pure silicon during cycling leads to particle pulverization, continuous rupture and regeneration of the SEI film, and loss of electrical contact between the active material and the current collector. This fully demonstrates the crucial role of indium antimonide composite in improving the cycling stability of the silicon anode: although some initial capacity is sacrificed, a significantly improved cycle life is achieved.

[0051] Comparative Example 2: Preparation and testing of silicon-indium antimonide composite materials by single-vibration ball milling: The preparation steps of this comparative example are exactly the same as those described in step S1 of Example 1 (Si:InSb=7:3). After obtaining the silicon-indium antimonide mixed powder, the acoustic resonance dispersion treatment in step S2 is not performed, and the composite anode material is directly dried to obtain the composite anode material.

[0052] The electrode preparation and battery assembly testing methods are the same as in Example 1. Figure 10 The cycling performance curves of this comparative example are included. The results show that the initial reversible specific capacity of the composite material is 2371.57 mAh / g, falling between that of pure silicon and the acoustically resonant treated composite. At a current density of 1.0 A / g, the initial capacity is 2106.27 mAh / g, and after 100 cycles, the reversible capacity is 611.26 mAh / g, with a capacity retention of only 29.0%, essentially equivalent to Comparative Example 1 (29.8%). This indicates that without the ball milling step and acoustic resonant dispersion, although InSb is introduced, the uneven dispersion and the presence of numerous agglomerates prevent the full utilization of InSb's conductivity and buffering properties. This comparative result strongly demonstrates the indispensability of the acoustic resonant dispersion step in the synergistic process of this invention.

[0053] Comparative Example 3: Preparation of silicon-indium antimonide composite material by single acoustic resonance device: Weigh 2.8 g of micron silicon powder with a particle size range of 1 μm to 5 μm (purity 99.9%) and 1.2 g of indium antimonide powder with a particle size range of 1 μm to 10 μm (purity 99.9%) (mass ratio of silicon to indium antimonide is 7:3), transfer them to a polytetrafluoroethylene container equipped with an acoustic resonance device, and add 4.0 g of absolute ethanol as the dispersion medium. After sealing the container, fix it on the resonance platform of an acoustic resonance mixing device (such as LabRAM or a device with the same function). Set the operating frequency of the device to 60 Hz, the acceleration to 50 g, and the processing time to 20 min. After the processing is completed, transfer the slurry to a vacuum drying oven and vacuum dry it at 80 °C for 8 h (vacuum degree ≤ -0.1 MPa). After complete drying, grind it evenly to obtain the silicon-indium antimonide composite negative electrode material of this comparative example.

[0054] The electrode preparation and battery assembly and testing methods are the same as those in Example 1. Figure 11 The cycle performance curve of this comparative example is included. The results show that the first reversible specific capacity of this composite material is 2539.6 mAh / g, which is between that of pure silicon and the composite material treated by acoustic resonance. At a current density of 1.0 A / g, the initial capacity of the first cycle is 2496.9 mAh / g. After 100 cycles, the reversible capacity is 325.8 mAh / g, and the capacity retention rate is only 12.9%. This shows that although InSb has been introduced with only the acoustic resonance dispersion step without planetary ball milling, due to the failure to form an effective composite interface between silicon and indium antimonide, the conductive and buffering effects of InSb cannot be fully exerted. This comparative result strongly proves the indispensability of the planetary ball milling step in the synergistic process of this invention.

[0055] Example 1 and Example 2 are far superior to Comparative Example 1 and Comparative Example 2 in terms of cycle stability, fully verifying the effectiveness of the "planetary ball milling - acoustic resonance dispersion" synergistic process and the InSb composite modification strategy of this invention. Although the initial capacity of Example 2 is lower than that of Example 1, its cycle stability is better, indicating that the increase in the content of InSb is beneficial to further improving the cycle life, and it can be optimized and selected according to specific requirements in practical applications.

[0056] Low-temperature performance test: Assembly and electrochemical performance test of coin cells: The pure silicon anode material of Comparative Example 1 (labeled Si-InSb-0 in the figure) and the Si-InSb-3 composite material of Example 1 were uniformly mixed with the conductive agent Super-P and the binder sodium carboxymethyl cellulose (CMC) in deionized water at a mass ratio of 8:1:1. The mixture was stirred at 2000 rpm for 30 min using a high-speed stirrer to prepare a uniform electrode slurry. The slurry was then uniformly coated onto battery-grade copper foil with a coating thickness of 200 μm, and subsequently transferred to a vacuum drying oven and dried at 80 °C for 12 h. After drying, the slurry was cut into 12 mm diameter discs to serve as working electrodes, with an active material loading of approximately 1.5 mg / cm².

[0057] In a high-purity argon glove box (water and oxygen content both <0.01ppm), a CR2032 coin cell was assembled using a lithium metal sheet as the counter electrode, a Celgard 2400 polypropylene membrane as the separator, and a solution of 1 mol / L lithium hexafluorophosphate (LiPF6) dissolved in ethylene carbonate / diethyl carbonate (volume ratio 1:2) with 10 wt% fluoroethylene carbonate (FEC) as the electrolyte. The addition of FEC helps to form a stable SEI film and improves cycle performance. Constant current charge-discharge tests were performed on a LAND CT2001A battery testing system with a voltage window of 0.01V to 1.5V (vs. Li / Li+) and a constant temperature of -10℃, denoted as Si-InSb-0-LT (low temperature) and Si-InSb-3-LT.

[0058] The charge-discharge curves for the first three cycles obtained from the Si-InSb-0-LT test are shown below. Figure 12 As shown in the figure, the initial discharge (lithium insertion) curve exhibits a typical silicon lithium insertion plateau below approximately 0.3V, while the initial charge (lithium removal) curve displays characteristic lithium removal behavior of silicon and indium antimonide. The anode material prepared in this embodiment was first activated at 0.2 A / g for 3 cycles at 30°C to form a stable SEI film. Subsequently, a long-cycle test was conducted at -10°C with a current density of 0.2 A / g. The initial reversible capacity was 2142.37 mAh / g. After 20 cycles at 0.2 A / g, the reversible capacity decreased from 2142.37 mAh / g to 1553.12 mAh / g, with a capacity retention rate of 72%. Figure 14 At -10℃, the extremely poor electronic conductivity of pure micron-sized silicon is further amplified, and the charge transfer impedance and lithium-ion migration impedance in the SEI film increase sharply. Pure silicon expands during lithium insertion and contracts during lithium extraction, causing the electrical contacts inside the electrode to break rapidly. Without the protection of an elastic conductive network, the particles easily detach from the current collector once they break, resulting in a decrease in capacity.

[0059] The first three charge-discharge curves obtained from the Si-InSb-3-LT test are shown in the figure below. Figure 13 As can be seen from the figure, the initial charge (lithiation) curve exhibits the characteristic lithium delithiation behavior of silicon and indium antimonide. The anode material prepared in this embodiment was first activated at 30°C with a low current of 0.2 A / g for 3 cycles to form a stable SEI film. Subsequently, a long-cycle test was conducted at -10°C with a current density of 0.2 A / g. The initial reversible capacity was 1316.59 mAh / g. After 20 cycles at 0.2 A / g, the reversible capacity increased from 1316.59 to 1612.86 mAh / g, showing a capacity ramp-up phenomenon. Figure 15 Compared to Si-InSb-O-LT, the cycling stability is significantly improved. At -10℃, micron-sized silicon particles undergo local refinement under charge-discharge stress, while the InSb metal network with high intrinsic electron mobility maintains excellent conductivity at low temperatures, enabling it to anchor newly generated silicon nanocrystal nuclei in real time and establish a continuous three-dimensional electron / ion interwoven network. This gradual interfacial activation not only significantly reduces low-temperature polarization but also maintains the mechanical integrity of the SEI film, giving the material unique low-temperature kinetic advantages.

[0060] Based on the disclosure and teachings of the foregoing specification, those skilled in the art can make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the present invention should also fall within the protection scope of the claims of the present invention. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on the present invention.

Claims

1. A silicon-indium antimonide composite anode material suitable for low-temperature environments, characterized in that, The composite anode material is granular, comprising silicon particles and indium antimonide particles, wherein the indium antimonide particles are uniformly distributed on the silicon particles; wherein the mass percentage of silicon is 60%~90%, and the mass percentage of indium antimonide is 10%~40%; the particle size of the silicon particles is 100-500 nm, the particle size of the indium antimonide particles is 50-300 nm, and the overall particle size of the silicon-indium antimonide composite anode material is 0.5-5 μm.

2. The method for preparing the silicon-indium antimonide composite anode material suitable for low-temperature environments as described in claim 1, characterized in that, Includes the following steps: S1. After mixing silicon powder and indium antimonide powder, place them in a vibrating ball mill and ball mill them under an inert atmosphere to obtain silicon-indium antimonide mixed powder; S2. Transfer the mixed powder obtained in step S1 to an acoustic resonance device, add a dispersant as a dispersion medium, start the acoustic resonance device for secondary dispersion treatment, and after drying, the silicon-indium antimonide composite anode material is obtained.

3. The method for preparing the silicon-indium antimonide composite anode material suitable for low-temperature environments as described in claim 2, characterized in that, In S1, the particle size range of the silicon powder is 1μm to 5μm, and the particle size range of the indium antimonide powder is 1μm to 10μm.

4. The preparation method of the silicon-indium antimonide composite anode material suitable for low-temperature environments as described in claim 2, characterized in that, In S1, the ball mill speed is 800-1200 rpm, the ball milling time is 2-24 hours, and the mass ratio of grinding balls to mixed powder during the ball milling process is 15:1-50:1; the inert atmosphere is argon atmosphere or nitrogen atmosphere.

5. The method for preparing the silicon-indium antimonide composite anode material suitable for low-temperature environments as described in claim 2, characterized in that, In S2, the dispersant includes one or more of anhydrous ethanol, isopropanol, n-hexane, polyvinylpyrrolidone solution, and stearic acid solution, and its addition amount is 15% to 200% of the total mass of the mixed powder.

6. The method for preparing the silicon-indium antimonide composite anode material suitable for low-temperature environments as described in claim 2, characterized in that, In S2, the operating frequency of the acoustic resonance device is 40Hz-70Hz, the acceleration is 30g-80g, and the processing time is 10min-60min.

7. The method for preparing the silicon-indium antimonide composite anode material suitable for low-temperature environments as described in claim 4, characterized in that, The grinding balls are made of zirconium oxide, including zirconium oxide with diameters of 5 mm and 10 mm mixed at a mass ratio of 2:

1.

8. The method for preparing the silicon-indium antimonide composite anode material suitable for low-temperature environments as described in claim 2, characterized in that, In S2, after drying, the mixed powder is ground evenly so that the particle size of silicon particles is 100-500 nm, the particle size of indium antimonide particles is 50-300 nm, and the overall particle size of silicon-indium antimonide composite anode material is 0.5-5 μm.

9. A negative electrode for a lithium-ion battery, characterized in that, The negative electrode comprises the silicon-indium antimonide composite negative electrode material suitable for low-temperature environments as described in claim 1, a conductive agent, and a binder, wherein the mass ratio of the silicon-indium antimonide composite negative electrode material, the conductive agent, and the binder is (7~8): (1~2):

1.

10. The application of the silicon-indium antimonide composite anode material suitable for low-temperature environments as described in claim 1, or the preparation method of the silicon-indium antimonide composite anode material suitable for low-temperature environments as described in any one of claims 2 to 8, in a lithium battery, characterized in that, The lithium battery operates in a low-temperature environment ranging from -40°C to 0°C.

Images