Lithium ion battery lithium vanadium silicate negative material and preparation method thereof

Abstract

This invention provides a lithium vanadium silicate anode material for lithium-ion batteries and its preparation method. The general chemical formula of the lithium vanadium silicate anode material is Li₂VSiO₅ or Li₂VOSiO₄, and its crystal structure is tetragonal with a space group of P₄ / nmm. Addressing the problems and challenges existing in current lithium-ion battery anode materials, this invention introduces polyanionic groups SiO₄ into vanadium-based transition metal oxides through material design and synthesis. Combined with a series of modification methods, including high-energy ball milling and in-situ carbon coating technology, a lithium vanadium silicate anode material with improved electrochemical performance is synthesized. This material exhibits excellent electrochemical performance as a lithium-ion battery anode material, such as high safety, high capacity, low operating potential, high rate capability, and excellent wide-temperature performance, making it a very promising lithium-ion battery anode material.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion batteries, and more specifically to a lithium vanadium silicate lithium anode material for lithium-ion batteries and its preparation method. Background Technology

[0002] Lightweight, rechargeable, and high-energy lithium-ion batteries are used globally in various products such as mobile phones, laptops, and electric vehicles. They can also store large amounts of energy from solar and wind power, making a fossil fuel-free society possible. As the application scenarios for lithium-ion batteries continue to expand, higher demands are being placed on their electrochemical performance. The energy density, cycle life, and safety of existing lithium-ion battery systems need further improvement to better meet these growing needs.

[0003] Research on high-Ni cathode and high-voltage cathode materials has greatly improved the performance of cathode materials. In comparison, lithium-ion battery anode materials still face greater challenges. Currently, lithium-ion battery anode materials can be summarized into three main categories, each with its own advantages, but also obvious disadvantages. (1) Carbon-based anode materials, represented by graphite, are the most widely used lithium-ion battery anode materials due to their low working potential and large specific capacity (372 mAh / g). However, graphite anodes may precipitate lithium metal during high-current discharge, posing a significant safety risk. (2) Alloy anode materials, represented by elemental silicon, show promising application prospects due to their ultra-high theoretical capacity (3589 mAh / g). However, silicon anode materials undergo huge volume expansion after lithium intercalation, limiting their cycle life. (3) Transition metal oxides, such as vanadium oxide and titanium oxide, have high safety, long life and high rate characteristics, showing great application prospects and have received widespread attention in recent years. However, the high lithium intercalation potential of these anode materials severely limits the output voltage and energy density of the full battery system.

[0004] Recently, Professor Xia Yongyao's research group at Fudan University reported that lithium titanium silicate (Li₂TiSiO₅) can provide 308 mAh / g as a negative electrode material for lithium-ion batteries, with an average lithium intercalation potential of 0.28 V vs. Li / Li. + The research results show that the SiO4 anionic group can effectively regulate the working potential of the electrode material and improve the energy density of titanium-based anode materials. Compared with titanium (Ti), vanadium (V) has more advantages, such as its abundant reserves in the Earth's crust and the ability to provide more capacity through multi-electron reactions. Lithium vanadium silicate (Li2VSiO5) is theoretically a very promising anode material for lithium-ion batteries, but currently there are no articles or patents reporting on its use as anode material for lithium-ion batteries.

[0005] Satto et al. reported Li₂VO₄(Si) in 1998. 1-x Ge x The synthesis method of Li₂VOSiO₄ (x=0,0.5,1) and the crystal structure of the material were studied (Materials Research Bulletin, Vol.33, No.9, pp.1339–1345, 1998). Li₂VOSiO₄ was obtained by solid-state sintering of raw materials Li₂SiO₃ and VO₂ at high temperature.

[0006] In 2006, Tarascon et al. synthesized Li₂VOSiO₄ using the same method and studied its electrochemical performance as a cathode material for lithium-ion batteries (Chem. Mater. 2006, 18, 407-412). The results showed that the average operating potential of this material as a cathode material for lithium-ion batteries was 3.6 V vs. Li / Li. + .

[0007] In 2008, Wan Chunrong et al. disclosed a method for preparing lithium vanadium silicate, a cathode material for lithium-ion batteries (see Chinese Invention Patent CN200810117701.8). This method involves preparing a precursor from lithium, vanadium, silicon, and carbon sources via a sol-gel reaction. After drying, the precursor is subjected to high-temperature heat treatment at 600-900℃ for 8-48 hours under an inert and reducing atmosphere to obtain lithium vanadium silicate powder. The resulting lithium vanadium silicate powder consists of nanoscale particles, exhibiting good conductivity and high specific capacity. At a 1C rate, the reversible specific capacity is greater than 160 mAh / g in the 3-4.8V charge-discharge range, and greater than 285 mAh / g in the 1.5-4.8V charge-discharge range, with excellent cycle performance.

[0008] In 2012, Tan Qiangqiang et al. disclosed a lithium vanadium silicate cathode material, its preparation method, and its applications (see Chinese Invention Patent CN201210407686.7). The chemical formula of this lithium vanadium silicate is Li6V2(SiO4)3, and they also reported how heteroelement doping improves the lithium storage performance of this material. At a C / 5 rate, within a charge-discharge range of 1.5–4.8V, the initial discharge specific capacity can reach a maximum of 275 mAh / g, and the capacity retention rate after 40 cycles is greater than 78%.

[0009] In 2020, Li Wenwu and others publicly disclosed L i2 VSi 1-x Ge xO5(0≤x≤1) anode material for lithium-ion batteries, its preparation method and application (see Chinese invention patent CN202010157800.X). This anode material has a moderate discharge platform, high capacity. After assembling a half-cell, the initial discharge specific capacity of this anode material is about 1300 mAh / g. During the charge-discharge process, it has small volume expansion and good electrical conductivity, and has good cycle performance and rate performance.

[0010] In 2021, Sun Xiaofei et al. disclosed a lithium vanadium fluorophosphate silicate cathode material and its preparation method (see Chinese invention patent CN202110851614.0), and its molecular formula is: LiVP 1-x Si x O4F, 0 < x < 1. The lithium vanadium fluorophosphate silicate prepared by the simple solid-phase sintering method in this invention has significant advantages such as stable structure, good safety, large specific capacity, high potential platform, small polarization, fast charge-discharge rate, and stable cycle.

[0011] However, the disadvantages of the above prior arts are as follows: 1) The theoretical capacity of graphite anode materials is relatively low, and the lithium intercalation potential is close to the precipitation potential of lithium metal; 2) Alloy-based elemental anode materials have very large volume expansion during the lithium intercalation process, severely limiting the cycle life of the battery; 3) The lithium intercalation potential of transition metal oxides is high, restricting the energy density of the lithium-ion battery system.

[0012] The reasons for the above disadvantages are as follows: 1) The low theoretical capacity of graphite anodes is determined by the electrochemical reaction mechanism. Graphite and lithium can form a stable compound Li6C, and its theoretical capacity is only 372 mAh / g. The actual capacity is also affected by many factors. The actual capacity of graphite anode materials is only 320 mAh / g, and the lithium intercalation potential is determined by thermodynamic and kinetic factors and cannot be regulated; 2) The reaction mechanism causes the formation of new phases during the lithium intercalation of alloy elemental anodes, and the volume of the alloy will undergo huge volume expansion compared with the unreacted metal element; 3) The thermodynamic lithium intercalation potential of transition metal oxides is relatively high. Summary of the Invention

[0013] The purpose of the present invention is to provide a lithium vanadium silicate anode material for lithium-ion batteries and its preparation method, so as to solve the problems of relatively low theoretical capacity, short battery cycle life, or low energy density existing in the anode materials of lithium-ion batteries in the prior art.

[0014] To solve the above problems, the present invention adopts the following technical solutions:

[0015] According to the first aspect of the present invention, there is provided a lithium vanadium silicate anode material for lithium-ion batteries. The chemical general formula of the lithium vanadium silicate anode material for lithium-ion batteries is Li2VSiO5 or Li2VOSiO4, and its crystal structure is tetragonal, and the space point group is P4 / nmm.

[0016] According to a second aspect of the present invention, a method for preparing the lithium-ion battery lithium vanadium silicate anode material is provided, comprising the following steps: S1, ball milling and mixing: lithium salt, vanadium salt and silicon source are mixed in a solid phase according to the molar ratio of their chemical composition, and ball milled at 200-500 rpm for 2-5 hours using a conventional planetary ball mill; S2, tableting: the obtained mixture is tableted under pressure between 15-30 MPa; S3, calcination: the tableted precursor is calcined at 900-1000℃. S4, High-energy ball milling: High-energy ball milling is performed using a high-energy ball mill at a speed greater than 800 rpm for more than 10 hours to reduce the particle size to about 0.5-1.0 μm; S5, In-situ carbon coating: In-situ carbon coating is performed by chemical vapor deposition, atomic deposition, molecular deposition, or thermal carbon reduction to uniformly coat a carbon layer with a thickness of 2-10 nm on the surface of the material, thus obtaining a lithium vanadium silicate lithium anode material for lithium-ion batteries.

[0017] Preferably, the lithium salt includes lithium carbonate, lithium silicate, lithium hydroxide, and lithium acetate; the vanadium salt includes vanadium dioxide, ammonium metavanadate, vanadium oxalate, vanadium tetrachloride, and vanadium trichloride; and the silicon source includes silicon dioxide, lithium silicate, and tetraethyl orthosilicate.

[0018] Preferably, in step S5, the carbon source used includes glucose, sucrose, citric acid, asphalt, and toluene.

[0019] Preferably, in step S5, the calcination temperature is 700-800℃ and the calcination time is 2-12 hours.

[0020] Preferably, the chemical vapor deposition includes: passing an inert gas into a toluene solution, allowing the toluene-carrying gas to pass through the raw material, and continuously venting at 700-800°C for 2-5 hours.

[0021] Preferably, the atomic deposition or molecular deposition includes: uniformly depositing organic matter or organic precursors on the surface of lithium vanadium silicate using a magnetron sputtering instrument or a molecular deposition instrument, and heat-treating at 700-800°C for 2-5 hours in an inert atmosphere.

[0022] Preferably, the preparation method further includes a thermal carbon reduction method, which aims to obtain carbon by heat-treating organic precursors such as sucrose, glucose, and pitch at high temperatures. Specifically, 8-12% by mass of an organic polymer, selected from glucose, sucrose, citric acid, or pitch, is added during high-energy ball milling, and in-situ carbon encapsulation is achieved by heat treatment at 700-800°C for 2-5 hours under an inert argon atmosphere.

[0023] It should be understood that the lithium salt, vanadium salt and silicon source mentioned above can be combined in any molar ratio. For example, lithium carbonate + silicon dioxide + vanadium dioxide, lithium silicate + vanadium dioxide, lithium acetate + silicon dioxide + vanadium dioxide, etc. are all feasible.

[0024] The preparation method of Li2VSiO5, a lithium-ion battery anode material according to the present invention, mainly includes the following steps: mixing and ball milling, pressing, calcination, high-energy ball milling, and in-situ carbon coating. The ball milling and mixing process ensures thorough and uniform mixing of the reactant precursors. Pressing at 15-30 MPa ensures sufficient contact of the reactants and inhibits the volatilization of lithium salts at high temperatures. Calcination aims to generate lithium vanadium silicate compounds. Since directly calcined lithium vanadium silicate particles are relatively large (above 10 μm), they are unsuitable as anode materials. By using a high-energy ball mill at a speed greater than 800 rpm for more than 10 hours, the particle size of lithium vanadium silicate can be reduced from greater than 10 μm to approximately 0.5-1 μm. Lithium vanadium silicate is a semiconductor with low electronic conductivity, limiting its electrochemical performance as a battery anode material. In-situ carbon coating, by coating a 2-10 nm thick carbon layer on the material surface, improves the electronic conductivity and thus enhances the electrochemical performance.

[0025] It should be noted that in the lithium-ion battery anode material system, the electrochemical performance of graphite anodes, alloy anodes, and transition metal oxide anodes is difficult to change through modification studies, including doping, carbon loading, and nano-sizing, but the lithium intercalation potential of the electrode material is hard to alter.

[0026] To address the shortcomings of existing lithium-ion battery anode materials, this invention presents a novel lithium-ion battery anode material, Li₂VSiO₅, through material design, synthesis, and modification. This material differs from existing lithium-ion battery anode material systems; it exhibits higher lithium storage capacity and lithium intercalation potential than graphite anodes, less volume expansion than alloy anode materials, and lower lithium intercalation potential and better cycle performance than transition metal oxides (such as vanadium oxide). The purpose of this invention is to develop a high-performance lithium-ion battery anode material to improve the electrochemical performance of lithium-ion batteries.

[0027] This invention discloses for the first time a tetragonal Li₂VSiO₅ lithium-ion battery anode material with a space group of P₄ / nmm. Based on its crystal structure, its molecular formula is Li₂VOSiO₄, a crystal structure of lithium vanadium silicate never before disclosed in existing technologies. As a novel electrode material never before researched and reported, it is expected to further improve the electrochemical performance of lithium-ion batteries, including energy density, safety, and cycle life.

[0028] While patent CN115784247A discloses a low-voltage negative electrode material for Li2VSiO5 lithium-ion batteries, its preparation method, and applications, it does not disclose its discharge curve, nor does it specify how low the potential is. The charge-discharge curve of this invention shows an average discharge voltage of 0.5V vs. Li / Li. + Furthermore, the discharge cutoff potential of this invention is 0.01V vs. Li / Li + Unlike the 0.25V vs. Li / Li disclosed in patent CN115784247A. + The tetragonal structure of Li2VOSiO4 itself has poor electronic conductivity. This invention demonstrates through experiments that carbon coating technology can effectively improve its electrochemical performance. However, patent CN115784247A does not mention any modification strategy for lithium vanadium silicate materials.

[0029] The biggest difference between this invention and previously published documents or patents is that: 1) The high-purity Li2VSiO5 synthesized in this invention is used as a negative electrode material for lithium-ion batteries, unlike its previously reported use as a positive electrode material for lithium-ion batteries; 2) To address the challenges of using Li2VSiO5 as a negative electrode material, this invention proposes an in-situ carbon coating technology to obtain carbon-coated Li2VSiO5. The negative electrode material obtained by this synthesis process not only has excellent performance but is also easy to mass-produce; 3) Compared with other lithium-ion battery negative electrode materials, the carbon-coated Li2VSiO5 negative electrode material has advantages such as high capacity, high rate capability, and long cycle life, and has great market potential.

[0030] The key inventive point of this invention lies in the fact that in-situ carbon coating technology can effectively improve the electrochemical performance of Li₂VSiO₅ without altering its structure. Carbon coating technologies include chemical vapor deposition, atomic deposition, molecular deposition, and thermal carbon reduction. In terms of synthesis methods, this invention uses a solid-state method. High-purity carbon-coated Li₂VSiO₅ material is prepared through a simple solid-state ball milling and solid-state sintering process combined with in-situ carbon coating technology. This material exhibits excellent electrochemical performance as a lithium-ion battery anode material. Compared to other methods, such as sol-gel and co-precipitation methods, the method used in this invention is highly suitable for large-scale preparation, offering cost advantages. Furthermore, the route used highly overlaps with existing commercial electrode material preparation processes, further reducing costs.

[0031] Compared with the prior art, the present invention has the following advantages:

[0032] 1) The synthesized carbon-coated Li₂VSiO₅ exhibits excellent electrochemical performance. Compared to graphite anode materials, Li₂VSiO₅ anode materials show higher reversible capacity and higher lithium intercalation potential. Compared to alloy-based anode materials, it exhibits less volume expansion and superior cycle performance. This invention, through material structure design, introduces polyanionic SiO₄ groups into the bulk phase of a transition metal V-based oxide, altering the coordination environment around V atoms and the electronic state of d orbitals to regulate the lithium intercalation potential of the V-based anode material. Simultaneously, the introduction of polyanionic groups stabilizes the structure of the electrode material during lithium-ion insertion / extraction, improving the material's cycle life.

[0033] 2) The raw materials used are inexpensive, giving it a cost advantage. This invention reduces material costs by selecting inexpensive elements and raw materials, such as lithium silicate (Li2SiO3) and vanadium dioxide (VO2). Compared with nano-alloy anode materials and high-temperature heat-treated graphite anode materials, Li2VSiO5 has a cost advantage. Both of these raw materials can achieve 100% atomic utilization.

[0034] 3) The preparation method is solid-state sintering, which facilitates the large-scale preparation of materials. This invention uses a solid-state method to synthesize carbon-coated Li₂VSiO₅. Carbon-coated Li₂VSiO₅ was prepared through solid-state ball milling and high-temperature sintering. Compared with other synthesis methods, this method has advantages such as low cost and ease of scale-up.

[0035] In summary, to overcome the shortcomings of existing lithium-ion battery anode materials, this invention designs and synthesizes a novel lithium-ion battery anode material, Li₂VSiO₅, and its preparation method. Addressing the problems and challenges of current lithium-ion battery anode materials, this invention, through material design and synthesis, introduces polyanionic groups (SiO₄) into vanadium(V)-based transition metal oxides, thus synthesizing lithium vanadium silicate (Li₂VSiO₅) material. This material exhibits excellent electrochemical performance as a lithium-ion battery anode material, such as high safety, high capacity, low operating potential, high rate capability, and excellent wide-temperature performance, making it a very promising lithium-ion battery anode material. Attached Figure Description

[0036] Figure 1 The X-ray diffraction pattern of the carbon-coated Li2VSiO5 material prepared in Example 1 is shown.

[0037] Figure 2 A scanning electron microscope image of the carbon-coated Li2VSiO5 material prepared in Example 1 is shown.

[0038] Figure 3A high-magnification transmission electron microscope image of the carbon-coated Li2VSiO5 material prepared in Example 1 is shown.

[0039] Figure 4 The constant current charge-discharge curves (first three cycles) of the carbon-coated Li2VSiO5 material prepared in Example 1 are shown.

[0040] Figure 5 The constant current charge-discharge curves of the carbon-coated Li2VSiO5, lithium titanate, and graphite anode materials prepared in Example 1 are shown.

[0041] Figure 6 The cycling stability of the carbon-coated Li2VSiO5 material prepared in Example 1 is shown. Detailed Implementation

[0042] The present invention will be further described below with reference to specific embodiments. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0043] Example 1

[0044] 1.1 Preparation of a carbon-coated Li₂VSiO₅ material (using lithium silicate as raw material)

[0045] According to the chemical composition of lithium vanadium silicate (Li₂SiO₃), raw materials lithium silicate (Li₂SiO₃) and vanadium dioxide (VO₂) were mixed in a 1:1 molar ratio using solid-state ball milling for 4 hours at a speed of less than 500 rpm (equipment: Nanjing Nanda Instrument Co., Ltd. - QM-3SP4 planetary ball mill) to ensure thorough mixing. The resulting mixture was then pressed into tablets at a pressure of 20 MPa. The resulting precursor was calcined in a tube furnace at 900℃ for 24 hours in an argon atmosphere. The resulting sample was then subjected to high-energy ball milling for 10 hours at a speed of 800-1000 rpm (equipment: German FRITSCH P7 small planetary ball mill, enhanced type) to reduce particle size, resulting in a particle size of 0.5-1 μm. Subsequently, in-situ carbon encapsulation was performed using chemical vapor deposition to improve the electronic conductivity of the material. The vapor deposition conditions were as follows: toluene was carried by flowing argon gas as a carbon source and calcined at 700°C in an argon atmosphere for 2 hours, and then naturally cooled to room temperature to prepare a carbon-coated Li2VSiO5 material.

[0046] Figure 1 The X-ray diffraction pattern of carbon-coated Li₂VSiO₅ is shown. The X-ray diffraction pattern of Li₂VSiO₅ corresponds well with the standard PDF card, and there are no miscellaneous terms. Its crystal structure is tetragonal, with a space group of P⁴ / nm. After ball milling, the carbon-coated Li₂VSiO₅ exhibits an irregular morphology with a particle size of approximately 1 μm. Figure 2 Nanoscale carbon layers are uniformly distributed on the surface of Li₂VSiO₅ material. High-magnification transmission electron microscopy images show that the carbon layer thickness is approximately 2 nm, and the coating layer is very uniform. Figure 3 ).

[0047] 1.2 Electrochemical performance determination of carbon-coated Li₂VSiO₅ material

[0048] The obtained carbon-coated Li₂VSiO₅ material was mixed with a conductive agent (carbon black) and a binder (polytetrafluoroethylene) in a certain ratio (e.g., 8:1:1). A certain amount of solvent (N-methylpyrrolidone) was added to prepare a homogeneous slurry. The slurry was then uniformly coated onto a copper foil (current collector) with a coating thickness between 20 and 100 μm. The resulting film was placed in an 80°C oven for vacuum drying for 12 hours. It was then punched into discs with a diameter of 12 μm, weighed, and transferred to a glove box for later use (water and oxygen content less than 0.1 ppm).

[0049] A 2032-type button cell was assembled, using lithium metal as both the counter and reference electrodes. The electrolyte consisted of 1 mole of lithium hexafluorophosphate (LiPF6) dissolved in a ethylene carbonate solvent. An organic polyethylene (PE) membrane was used as the separator. At a current density of 50 mA / g, the initial discharge and charge capacities were 760.5 mAh / g and 630 mAh / g, respectively, corresponding to an initial coulombic efficiency of 82.8% and an average lithium intercalation potential of 0.5 V vs. Li / Li. + ( Figure 4 Compared to currently commercialized lithium-ion battery anode materials, such as graphite anode materials and lithium titanate (Li4Ti5O4), 12 The anode material, carbon-coated Li₂VSiO₅, exhibits high reversible capacity and high safe lithium intercalation potential. Figure 5 At a current density of 200 mA / g, the capacity remains at 524 mA / g after 200 cycles, corresponding to a capacity retention of 95.6%. Figure 6 The results show that carbon-coated Li2VSiO5 exhibits excellent cycle stability as a negative electrode material for lithium-ion batteries.

[0050] Example 2: Preparation of a carbon-coated Li₂VSiO₅ material (using lithium carbonate as raw material)

[0051] According to the chemical composition of lithium vanadium silicate (Li₂VSiO₅), raw materials lithium carbonate (Li₂CO₃), silicon dioxide (SiO₂), and vanadium dioxide (VO₂) were mixed by solid-phase ball milling at a molar ratio of 1:1:1 for 4 hours. The resulting mixture was then pressed into tablets at a pressure of 20 MPa. The resulting precursor was calcined in a tube furnace at 900 °C for 24 hours in an argon atmosphere. The obtained sample was then ball-milled at high energy for 10 hours, followed by in-situ carbon coating via chemical vapor deposition to improve the material's electronic conductivity. The vapor deposition conditions were as follows: using flowing argon gas carrying toluene as a carbon source, calcining at 700 °C in an argon atmosphere for 2 hours, and then naturally cooling to room temperature to obtain carbon-coated Li₂VSiO₅ material.

[0052] Example 3: Preparation of a carbon-coated Li2VSiO5 material (thermal carbon reduction, using pitch as the carbon source).

[0053] According to the chemical composition of lithium vanadium silicate (Li₂VSiO₅), raw materials lithium silicate (Li₂SiO₃) and vanadium dioxide (VO₂) were mixed by solid-phase ball milling at a molar ratio of 1:1 for 4 hours. The resulting mixture was then pressed into tablets at a pressure of 20 MPa. The resulting precursor was calcined in a tube furnace at 900 °C for 24 hours in an argon atmosphere. The resulting sample was then ball-milled at high energy for 10 hours, with 10% (w / w) of pitch added. The resulting sample was then calcined at 700 °C in an argon atmosphere for 2 hours, and then naturally cooled to room temperature to obtain carbon-coated Li₂VSiO₅ material.

[0054] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention. Various variations can be made to the above embodiments of the present invention. All simple and equivalent changes and modifications made in accordance with the claims and description of this application fall within the protection scope of the claims of this patent. All aspects not described in detail in this invention are conventional technical content.

Claims

1. A method for preparing a lithium vanadium silicate negative material for lithium ion batteries, characterized in that, Includes the following steps: S1, ball milling: lithium salt, vanadium salt and silicon source are mixed in solid phase according to the molar ratio of their chemical composition, and ball milled at 200-500 rpm for 2-5 hours using a common planetary ball mill; S2, tableting: The resulting mixture is tableted at a pressure between 15-30 MPa. S3, Calcination: The precursor that has been compressed is calcined at 900-1000 ℃ for 12-36 hours in an argon atmosphere to obtain lithium vanadium silicate material. S4, High-energy ball milling: High-energy ball milling is performed using a high-energy ball mill at a speed greater than 800 rpm for a time greater than 10 hours, reducing the particle size to 0.5-1.0 μm; S5, In-situ carbon coating: In-situ carbon coating is performed via chemical vapor deposition, atomic deposition, molecular deposition, or thermal carbon reduction to uniformly coat a 2-10 nm thick carbon layer onto the surface of lithium vanadium silicate material, thus obtaining a lithium-ion battery lithium vanadium silicate anode material with the general chemical formula Li₂VSiO₅ or Li₂VOSiO₄. The chemical vapor deposition includes: passing an inert gas through a toluene solution, allowing the toluene-carrying gas to pass through the raw material, and continuously purging at 700-800°C for 2-5 hours; or the atomic or molecular deposition includes: uniformly depositing organic matter or organic precursors on the surface of lithium vanadium silicate using a magnetron sputtering instrument or a molecular deposition instrument, under an inert atmosphere at 700-800°C. Heat treatment at ℃ for 2-5 hours; or the thermal carbon reduction includes: adding 8-12% by mass of an organic polymer, selected from glucose, sucrose, citric acid, or asphalt, during high-energy ball milling, and achieving in-situ carbon encapsulation by heat treatment at 700-800℃ for 2-5 hours under an inert argon atmosphere.

2. The production method according to claim 1, characterized by, The lithium salts include lithium carbonate, lithium silicate, lithium hydroxide, and lithium acetate; the vanadium salts include vanadium dioxide, ammonium metavanadate, vanadium oxalate, vanadium tetrachloride, and vanadium trichloride; and the silicon source includes silicon dioxide, lithium silicate, and tetraethyl orthosilicate.

3. A lithium-ion battery lithium vanadium silicate anode material prepared by the preparation method according to any one of claims 1-2, characterized in that, Its crystal structure is tetragonal, and its space point group is P4 / nmm .

Images