Negative electrode material and method for manufacturing the same, lithium-ion battery

Abstract

This application relates to the lithium battery technology, and more particularly to negative electrode materials and methods for manufacturing the same, and to lithium-ion batteries, wherein the negative electrode material includes an active material, the active material includes Si element, O element, and metal M element, the metal M includes Mg, Ca, and Cu, and in the negative electrode material, the mass content of Mg element is m Mg Therefore, the mass content of element Ca is m Ca Therefore, the mass content of the element Cu is m Cu and 0 <m Ca / m Mg <0.1, 0 <m Cu / m Mg The value is <0.01. In the anode material of this application, Mg, Ca, and Cu elements are introduced into the active material, and the ratio values ​​of Mg, Ca, and Cu are limited to an appropriate range, thereby improving the initial cloning efficiency, conductivity, cycle performance, and lithium absorption / release rate of the anode material.

Description

[Technical Field]

[0001] [Cross-reference of related applications] This application claims priority to Chinese patent application 2023118306082, filed on December 27, 2023. This application incorporates the entire text of the aforementioned Chinese patent application.

[0002] This application relates to the field of lithium battery technology, and more particularly to negative electrode materials, methods for manufacturing the same, and lithium-ion batteries. [Background technology]

[0003] Silicone-based anode materials have the highest lithium storage capacity and a relatively low voltage plateau, making them one of the hot spots in lithium-ion battery anode material research. However, the commercial application of silicone materials is limited by their huge volume expansion coefficient (>300%) and relatively low conductivity. Although the theoretical capacity of SiO is lower than that of silicone, the strength of the Si-O bond is twice that of the Si-Si bond, and the Li2O compound produced in the first cycle reaction process has a buffering effect against volume expansion, resulting in much better cycle performance than silicone. However, at the same time, too much Li2O increases the consumption of Li ions in the cathode material during the initial charge, increasing the irreversible capacity of the material and reducing the initial cloning efficiency.

[0004] Conventional techniques involve doping silicone-based anode materials with several reducing Mg elements to uniformly distribute Si, O, and Mg in the anode material, thereby increasing the irreversible capacity of the anode material. However, while the silicone-based anode materials produced in this way show some improvement in their initial cloning efficiency, they still suffer from low conductivity and poor cycle performance. [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] This application is advantageous for comprehensively improving the first Coulombic efficiency, conductivity, and cycle performance of the negative electrode material, and solves the problem that it is difficult for the negative electrode material in the prior art to achieve both good first Coulombic efficiency, conductivity, and cycle performance. A negative electrode material, a method for manufacturing the same, and a lithium-ion battery are provided.

Means for Solving the Problems

[0006] According to a first aspect, an embodiment of this application provides a negative electrode material. The negative electrode material includes an active material, and the active material includes Si element, O element, and metal M element. Metal M includes Mg, Ca, and Cu. In the negative electrode material, the mass content of Mg element is m Mg whereas the mass content of Ca element is m Ca whereas the mass content of Cu element is m Cu where 0 < m Ca / m Mg < 0.1 and 0 < m Cu / m Mg < 0.01.

[0007] According to a second aspect, this application further proposes a method for manufacturing a negative electrode material. The manufacturing method includes mixing a raw material of silicon-based active particles and a metal doping source containing M element, performing heat treatment, mixing the formed vapor, and then cooling to obtain an active material. The negative electrode material includes the active material, and the active material includes Si element, O element, and metal M element. Metal M includes Mg, Ca, and Cu. In the negative electrode material, the mass content of Mg element is m Mg whereas the mass content of Ca element is m Ca whereas the mass content of Cu element is m Cu where 0 < m Ca / m Mg < 0.1 and 0 < m Cu / m Mg < 0.01.

[0008] In a third aspect, the present application further proposes a lithium-ion battery comprising the negative electrode material described above, or a negative electrode material obtained by employing the manufacturing method described above. [Effects of the Invention]

[0009] This proposed technology has at least the following technical advantages compared to conventional technologies.

[0010] In the anode material of this application, Mg, Ca, and Cu elements are introduced into the active material, and the ratio values ​​of Mg, Ca, and Cu are limited to an appropriate range, thereby comprehensively improving the initial cloning efficiency, conductivity, and cycle performance of the anode material. In this application, the introduced Mg and Ca elements are advantageous in reducing the content of silicon oxide in the anode material, thereby increasing the initial cloning efficiency of the anode material by reducing the amount of lithium that can be consumed by the silicon oxide in the anode material. On the other hand, compared to Mg atoms, Ca atoms have lower electronegativity and larger bonds formed with O and / or Si atoms, which is advantageous in stabilizing the atomic cluster structure, thereby improving the structural stability of the anode material and enhancing its cycle performance. Ca / m Mg If the value is greater than 0.1, the capacity of the anode material is reduced, and the initial cloning efficiency decreases. Cu may exist in the anode material as a doping element in the form of at least one compound such as copper oxide, cuprous oxide, copper silicate, or copper silicide. Compared to Mg atoms, the number of electron layers of Cu atoms in Cu compounds is significantly higher, the electron transition energy barrier is lower, i.e., the electron capture ability is lower, the free electron fluidity of the outermost layer is good, m Cu / m Mg If the value is greater than 0.01, it reduces the structural stability of the anode material. Therefore, doping with Cu can improve the conductivity of the silicone oxygen anode material and enhance its cycling performance.

[0011] In the manufacturing method of this application, by doping silicone-based active particles with appropriate amounts of Mg, Ca, and Cu during the process of manufacturing the active material of the anode material, the ratio values ​​of Ca, Cu, and Mg in the finally manufactured anode material are controlled to be within an ideal range, and the manufactured anode material is given relatively high initial cloning efficiency, relatively high conductivity, better cycle performance, and a faster lithium absorption and release rate. In the technical proposal of this application, the introduced Mg and Ca elements react with the silicone oxide in the silicone-based active particles to produce elemental silicone, which is advantageous in reducing the content of silicone oxide in the anode material, and thereby increasing the initial cloning efficiency of the anode material by reducing the amount of lithium that can be consumed by the silicone oxide in the anode material. [Brief explanation of the drawing]

[0012] The drawings of the specification, which constitute part of this application, are used to provide a further understanding of this application, and the schematic embodiments and descriptions thereof are used to interpret this application and do not constitute an unreasonable limitation of this application. In the drawings, [Figure 1] This is a diagram illustrating the manufacturing process for the negative electrode material of this application. [Modes for carrying out the invention]

[0013] It should be noted that, as long as there are no conflicts, the embodiments and features described herein can be combined with each other. To better understand the technical proposal of this application, the embodiments of this application will be described in detail below, accompanied by drawings.

[0014] It should be made clear that the embodiments described are only a subset of, and not all, embodiments of this application. All other embodiments derived from the embodiments in this application, without the need for creative effort by a person skilled in the art, are all within the scope of protection of this application.

[0015] The terminology used in the embodiments of this application is for the sole purpose of describing specific embodiments and is not intended to limit this application. The singular forms “one kind,” “the foregoing,” and “this” used in the embodiments of this application and the accompanying claims also include the plural forms unless the context clearly indicates otherwise.

[0016] It should be understood that the terms "and / or" as used herein simply describe a relationship between related objects, and that three such relationships are possible. For example, A and / or B may represent three cases: A alone, A and B as a combination, or B alone. Also, the letter " / " in this specification generally indicates that the related objects before and after are in an "or" relationship.

[0017] Conventional techniques involve doping silicone-based anode materials with several reducing Mg elements to uniformly distribute Si, O, and Mg in the anode material, thereby increasing the irreversible capacity of the anode material. However, while the silicone-based anode materials produced in this way show some improvement in their initial cloning efficiency, they still suffer from low conductivity and poor cycle performance.

[0018] In response to this, those skilled in the art attempt to comprehensively improve the conductivity and cycle performance of anode materials by adjusting the distribution of each element's content. However, the above technical problem remains unresolved, mainly because each element in the anode material is interrelated with each other, acting synergistically and collectively affecting the overall performance of the material. However, it is difficult to obtain an appropriate control range for each parameter in the product using simple testing methods to assess the influence on multiple parameters.

[0019] In response to the above technical problem, according to the first aspect, this application proposes a negative electrode material.

[0020] In the embodiments of this application, the negative electrode material includes an active material, the active material includes Si, O, C, and metal M, and metal M includes Mg, Ca, and Cu, and in the negative electrode material, the mass content of Mg is m Mg Therefore, the mass content of element Ca is m Ca Therefore, the mass content of the element Cu is m Cu and 0 <m Ca / m Mg <0.1, 0 <m Cu / m Mg <0.01.

[0021] In the anode material of this application, the elements Mg, Ca, and Cu are introduced into the active material, and the ratio values ​​of Mg, Ca, and Cu are limited to an appropriate range, thereby comprehensively improving the initial cloning efficiency, conductivity, and cycle performance of the anode material. In this application, the introduced Mg and Ca elements are advantageous in reducing the content of silicon oxide in the anode material, and by reducing the amount of lithium that can be consumed by the silicon oxide in the anode material, the initial cloning efficiency of the anode material is increased.

[0022] In other words, based on the data from the examples and the analysis of beneficial effects, the applicant can conclude that the technical problems of this application can already be solved by controlling the content of Mg, Ca, and Cu elements within the above range, and that there is no need to limit the specific forms in which Mg, Ca, and Cu elements exist.

[0023] In the negative electrode material according to this application, M (M=Mg, Ca, or Cu) is dispersed in the silicone oxygen material in atomic form. Because the atomic electronegativity of M is lower than that of O and Si, M can combine with O or Si to form M-Si-O, MO, M-Si, etc., that is, at least one of M silicates, M oxides, or M silicides. For example, Ca atoms may form at least one of calcium silicate, calcium oxide, calcium silicide, etc.

[0024] In the anode material of this application, the form of Mg element is that it contains magnesium silicate, and compared to Mg atoms, the electronegativity of Ca atoms is low, and the bonds formed between them and O and / or Si atoms are large, which is advantageous for stabilizing the atomic cluster structure, thereby improving the structural stability of the anode material and enhancing its cycle performance.

[0025] Cu can exist as a doping element in the anode material in the form of at least one compound, such as copper oxide, cuprous oxide, copper silicate, or copper silicide. Compared to Mg atoms, the number of electron layers of Cu atoms in Cu compounds is significantly higher, resulting in a lower electron transition energy barrier, i.e., a lower electron capture ability and better free electron fluidity in the outermost layer. Therefore, doping with Cu can improve the conductivity of the silicone oxygen anode material and enhance its cycle performance.

[0026] In the anode material of this application, by introducing appropriate amounts of Mg, Ca, and Cu elements into the active material, the form of the Mg element includes magnesium silicate, the forms of the Ca and Cu elements both include metal compounds, and the metal oxide includes at least one of metal silicates, metal oxides, and silicides, thereby comprehensively improving the initial cloning efficiency, conductivity, and cycle performance of the anode material.

[0027] In some embodiments, the introduced Mg and Ca elements in appropriate mass content ratios exist in the negative electrode material in the form of magnesium silicate and calcium silicate. The stability of calcium silicate is superior to that of magnesium silicate, and the coexistence of magnesium silicate and calcium silicate in appropriate proportions to a single magnesium silicate can further improve the structural stability of the negative electrode material. As a result, batteries made with this negative electrode material can maintain relatively high conductivity in their negative electrode plates even after long-term charging and discharging, thus improving the cycle performance of the negative electrode material. Furthermore, the introduced Cu element in appropriate content can exist in the form of copper silicide in combination with Si. Appropriate amounts of copper silicide have good conductivity and ductility, and by reinforcing the structural stability and electrical contact effect of the negative electrode material, both the cycle performance and conductivity of the negative electrode material can be further improved.

[0028] In the negative electrode material of this application, m Ca / m Mg Specifically, this could be 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.099, etc., and of course, it could be any other value within the above range; it is not limited here. Ca / m Mg By limiting the value of to within the above range, the size of the silicon crystallites generated by the reaction of silicon oxide can be controlled to 15 nm or within 15 nm, thereby improving the cycle performance of the negative electrode material.

[0029] In the negative electrode material of this application, m Cu / m Mg Specifically, this could be 0.001, 0.002, 0.003, 0.004, 0.005, 0.006, 0.007, 0.008, 0.009, 0.0099, etc., and of course, it could be any other value within the above range, and is not limited thereto. Under the above conditions, it is more advantageous to control the content of copper silicides that may be generated and to improve the capacity of the negative electrode material.

[0030] For similar reasons, more preferably, in some embodiments, in the negative electrode material, 0.028 ≤ m Ca / m Mg ≤0.099, 0.0008 ≤m Cu / m Mg The value is ≤ 0.0099.

[0031] In some embodiments, the elements Si, O, Mg, Ca, and Cu are uniformly distributed in the active material, which is advantageous for improving the structural stability of different parts of the anode material, and thereby is advantageous for improving the overall cycle performance of the anode material.

[0032] In some embodiments, in the negative electrode material, 0 <m Mg <25%, m Mg Specifically, this could be 0.01%, 1%, 5%, 10%, 15%, 20%, 24.99%, etc., and of course, it could be any other value within the above range, and is not limited thereto. This application is m Mg Further restricting the value to within the above range is advantageous for improving the cycle performance and conductivity of the anode material, while maintaining that the capacity of the anode material is not significantly affected.

[0033] For similar reasons, more preferably, in some embodiments, in the negative electrode material, 5% ≤ m Mg ≤15%, preferably 7.8% ≤ m Mg The percentage is ≤8.7%.

[0034] In some embodiments, in the negative electrode material, 0 <m Ca <10%, m Ca Specifically, this could be 0.01%, 1%, 2%, 4%, 6%, 8%, 9.99%, etc., and of course, it could be any other value within the above range, and is not limited thereto. This application is m CaFurther limiting the value of to within the above range slows down the reaction process when the reaction occurs between Ca and silicon oxide in the material, further reducing the Si crystal grain size and providing the anode material with more suitable cycle performance.

[0035] For similar reasons, more preferably, in some embodiments, in the negative electrode material, 0.2% ≤ m Ca The percentage is ≤0.8%.

[0036] In some embodiments, in the negative electrode material, 0 <m Cu <0.5%, m Cu Specifically, this could be 0.01%, 0.1%, 0.2%, 0.3%, 0.4%, 0.499%, etc., and of course, it could be any other value within the above range, and is not limited thereto. This application is m Cu By further limiting the value to the above range, it is presumed that it is advantageous to incorporate an appropriate amount of copper silicide into the anode material, utilizing its good conductivity and ductility to improve the cycle performance and conductivity of the anode material, and further reduce the capacity reduction caused by too much copper silicide.

[0037] Based on the similarity, more preferably, in some embodiments, in the negative electrode material, 0.007% ≤ m Cu The percentage is ≤0.08%.

[0038] In some embodiments, the mass content of the silicon element in the negative electrode material is 24% to 36%, specifically 24%, 28%, 30%, 32%, 34%, 36%, etc., and of course, it may be any other value within the above range, and is not limited thereto.

[0039] In some embodiments, the mass content of oxygen in the negative electrode material is 44% to 59%, and may specifically be 44%, 48%, 50%, 53%, 55%, 57%, 59%, etc., and may, of course, be any other value within the above range, and is not limited thereto.

[0040] By further limiting the mass contents of silicon and oxygen elements in the negative electrode material within the above ranges, this application can fully react with the introduced Mg, Ca, and Cu elements to comprehensively improve the initial Coulombic efficiency, conductivity, and cycle performance of the negative electrode material. At the same time, by further reducing the lithium consumption of silicon oxide in the negative electrode material, it is beneficial to better improve the initial Coulombic efficiency of the negative electrode material.

[0041] In some embodiments, in the active material, the Si element exists in the form of elemental silicon and / or silicon oxide, and the Si crystallite size in elemental silicon and / or silicon oxide is ≦15 nm. A relatively low Si crystallite size is beneficial for further improving the cycle performance of the negative electrode material.

[0042] In some embodiments, in the active material, the Si element exists in at least one of the forms of amorphous silicon, crystalline silicon, silicon oxide, silicon alloy, and a composite of crystalline silicon and amorphous silicon.

[0043] In some embodiments, the active material contains silicon oxide, and the general formula of the silicon oxide is SiO x , where 0 < x ≦ 2, specifically it may be 0.1, 0.5, 1, 1.5, 2, etc. Of course, it may also be other values within the above range, and it is not limited here.

[0044] In some embodiments, the existing form of the metal M includes at least one of the silicate of M, the oxide of M, and the silicide of M.

[0045] In some embodiments, the active material contains at least one of calcium silicate, magnesium silicate, and copper silicide.

[0046] In some embodiments, the active material further contains elemental copper.

[0047] The fact that the above-mentioned active materials are produced by Mg, Ca, and Cu elements is advantageous in improving the initial cloning efficiency of the anode material, and by improving the structural stability of the anode material, it is possible to maintain relatively high conductivity during long-term charge-discharge processes, thereby further enhancing the cycle performance of the anode material.

[0048] In some embodiments, the negative electrode material further comprises a carbon material located on at least a portion of the surface of the active material. Placing a carbon layer on a portion of the surface of the active material is advantageous in reducing the formation of an SEI film due to direct contact between the active material and the electrolyte, thereby reducing the degradation of the material's cycle performance.

[0049] In some embodiments, the carbon material includes at least one of graphite, graphene, amorphous carbon, diamond-like carbon, carbon nanotubes, and carbon fibers. The carbon material can further improve the conductivity of the anode material by protecting the active material while simultaneously providing good conductivity. Here, amorphous carbon is a material that does not have characteristic peaks on the XRD pattern formed by the high-temperature decomposition of a carbon source. For example, amorphous carbon can be obtained by decomposing acetylene at 750°C to 850°C.

[0050] In some embodiments, a carbon layer is formed on the surface of the carbon material active material.

[0051] In some embodiments, the carbon layer coats the active material, which can effectively reduce the volume expansion coefficient of the negative electrode material.

[0052] In some embodiments, the thickness of the carbon layer is 50 nm to 200 nm, specifically 50 nm, 80 nm, 110 nm, 140 nm, 170 nm, 200 nm, etc., and of course, it may be any other value within the above range, and is not limited thereto. By limiting the thickness of the carbon layer to the above range, it is possible to completely coat the carbon layer with the active material and prevent the occurrence of a situation in which the electrolyte is excessively consumed and the material's cycle performance deteriorates due to the active material repeatedly coming into direct contact with the electrolyte and forming an unstable SEI film. Furthermore, the carbon layer does not become too thick and is not prone to cracking due to the action of its internal particle stress.

[0053] In some embodiments, the mass content of carbon in the negative electrode material is 1% to 20%, specifically 1%, 4%, 8%, 12%, 16%, 20%, etc., and of course, it may be any other value within the above range, and is not limited thereto. Under the above conditions, a balance between active material protection performance and conductivity can be achieved, and a desirable balance between conductivity and cycle performance can be better achieved.

[0054] In some embodiments, the pH value of the negative electrode material is 8 to 10, specifically 8.00, 8.50, 9.00, 9.50, 10, etc., and of course, it may be any other value within the above range, and is not limited thereto. Under the above conditions, it is compatible with most electrolytes, thereby improving the versatility of the negative electrode material.

[0055] In some embodiments, the average particle size D50 of the negative electrode material is 1 μm to 100 μm, specifically 1 μm, 10 μm, 20 μm, 40 μm, 60 μm, 80 μm, or 100 μm, and may, of course, be other values ​​within the above range, but is not limited thereto. An appropriate particle size is advantageous in reducing aggregation while simultaneously making the material easier to manufacture.

[0056] In some embodiments, the specific surface area of ​​the negative electrode material is 1 m². 2 / g~120m 2 It is / g, specifically 1 m 2 / g, 10 m 2 / g, 20 m 2 / g, 40 m 2 / g, 6 m 2 / g, 80 m 2 / g, 100 m 2 / g or 120 m 2 The value may be / g, or of course, any other value within the above range, and is not limited thereto. An appropriate specific surface area is advantageous in further improving the initial cloning efficiency of the anode material by further reducing the formation of SEI film during the initial charge-discharge cycle process.

[0057] As described above, in the anode material of this application, Mg, Ca, and Cu elements are introduced into the active material, and the ratio values ​​of Mg, Ca, and Cu are limited to an appropriate range, thereby comprehensively improving the initial cloning efficiency, conductivity, and cycle performance of the anode material.

[0058] Specifically, in some embodiments, the initial cloning efficiency of the negative electrode material is 80% to 95%, preferably 80% to 85%.

[0059] In some embodiments, the conductivity of the negative electrode material is 0.5 S / cm to 7 S / cm, preferably 2 S / cm to 7 S / cm.

[0060] In some embodiments, the capacity retention rate of the negative electrode material after 50 cycles is 80% to 90%.

[0061] In some embodiments, the plate expansion coefficient of the negative electrode material after 50 cycles is 30% to 38%.

[0062] A negative electrode material possessing the above performance parameters is more suitable as a component of lithium-ion batteries, further enhancing the overall electrochemical performance of the battery.

[0063] In a second aspect, the present application further proposes a method for manufacturing a negative electrode material, as shown in Figure 1.

[0064] In the embodiments of this application, the manufacturing method includes the following steps:

[0065] S1. A raw material for silicone-based active particles is mixed with a metal doping source containing element M, heat-treated, and the resulting vapor is mixed and then cooled to obtain an active material. The negative electrode material contains the active material, which contains Si element, O element, and metal M element, where metal M contains Mg, Ca, and Cu, and the mass content of Mg element in the negative electrode material is m Mg Therefore, the mass content of element Ca is m Ca Therefore, the mass content of the element Cu is m Cu and 0 <m Ca / m Mg <0.1, 0 <m Cu / m Mg <0.01.

[0066] In the manufacturing method of this application, by doping silicone-based active particles with appropriate amounts of Mg, Ca, and Cu during the process of manufacturing the active material for the anode material, the ratio values ​​of Ca, Cu, and Mg in the final manufactured anode material are controlled to be within an ideal range, and the manufactured anode material is given relatively high initial cloning efficiency, relatively high conductivity, better cycle performance, and a faster lithium absorption and release rate.

[0067] In the proposed technology of this application, the introduced Mg and Ca elements react with the silicone oxide in the silicone-based active particles to produce pure silicone, which is advantageous in reducing the content of the silicone oxide in the anode material, thereby increasing the initial cloning efficiency of the anode material by reducing the amount of lithium that can be consumed by the silicone oxide in the anode material. Furthermore, the introduced Mg and Ca elements react with the silicone oxide after reducing the silicone to produce the corresponding magnesium silicate and calcium silicate, and the stability of the calcium silicate is superior to that of the magnesium silicate, resulting in a single magnesium silicate. The coexistence of magnesium silicate and calcium silicate in appropriate proportions with magnesium silicate further improves the structural stability of the negative electrode material. Batteries made with this negative electrode material can maintain relatively high conductivity in their negative electrode plates even after long-term charging and discharging, thus enhancing the cycle performance of the negative electrode material. Furthermore, the introduced Cu element reacts with the generated silicon element to form a copper-silicon compound, reducing the amount of free-floating silicon element in the negative electrode material. This reinforces the structural stability of the negative electrode material and the electrical contact effect between negative electrode material particles, further improving both the cycle performance and conductivity of the negative electrode material.

[0068] In the manufacturing method of this application, m Ca / m Mg Specifically, this could be 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.099, etc., and of course, it could be any other value within the above range; it is not limited here. Ca / m Mg By limiting the value to the above range, the size of the silicon crystallites produced by the reaction of silicon oxide can be controlled to 15 nm or within 15 nm, m Ca / m Mg When the value of is too large, the reaction between Ca and silicon oxide becomes relatively vigorous, resulting in a large amount of heat dissipation during the reaction process and relatively large Si crystal grains, which leads to poor cycle performance of the resulting anode material.

[0069] In the manufacturing method of this application, m Cu / m Mg Specifically, this could be 0.001, 0.002, 0.003, 0.004, 0.005, 0.006, 0.007, 0.008, 0.009, 0.0099, etc., and of course, it could be any other value within the above range, and is not limited here. When the mass content ratio of Cu to Mg is too high, the amount of copper silicide produced is too large, and too much copper silicide leads to a decrease in the volume of the material.

[0070] In some embodiments, the mass ratio of the metal doping source of element M to the raw material of the silicone-based active particles is (1-35):100, specifically 1:100, 10:100, 20:100, 30:100, 35:100, etc., and of course, other values ​​within the above range are also acceptable and are not limited thereto. Within the above mass ratio range, it is advantageous to further improve the cycle performance and conductivity of the anode material by introducing elements Mg, Ca, and Cu to produce appropriate amounts of magnesium silicate, calcium silicate, and copper-silicon compounds.

[0071] In some embodiments, the metal doping source includes at least one of a pure metal M and a compound containing metal M.

[0072] In some embodiments, the metal doping source comprises a mixture of an oxide and / or salt containing metal M and a reducing substance.

[0073] In some embodiments, the salts containing metal M include at least one of MgCO3, MgCl2, CaCO3, dolomite, and copper-stained dolomite.

[0074] The above-mentioned metal doping sources are less expensive, easier to obtain, and advantageous in further reducing the manufacturing cost of anode materials, making them more suitable for industrial production and application.

[0075] In some embodiments, the raw materials for the silicone-based active particles are Si, SiOy A mixture of SiO2 and SiO2. y It comprises at least one of a mixture of and Si, or a mixture of Si and SiO2, where 0 <y<2である。

[0076] In some embodiments, the molar amount of element M in the metal doping source is n M and 0 <n Ca / n Mg <1.8, 0 <n Cu / n Mg <0.3. By limiting the molar content ratio of calcium, copper, and magnesium elements in the metal doping source to the above range, the mass content ratio of calcium, copper, and magnesium elements in the active material of the anode material obtained by manufacturing is 0 <m Ca / m Mg <0.1, 0 <m Cu / m Mg It is possible to ensure that the condition <0.01 is met.

[0077] In some embodiments, the molar amount of element M in the metal doping source is n M Therefore, the molar amount of Si in the raw material for silicone-based active particles is n Si and n M :n Si =(0.02~0.62):1, specifically the ratio of 0.02:1, 0.1:1, 0.2:1, 0.4:1, 0.62:1, or any value in between. By limiting the molar ratio of element M in the metal doping source to the silicon element in the raw material of the silicon-based active particles within the above range, the initial cloning efficiency, conductivity, and cycle performance of the manufactured anode material can be significantly and comprehensively improved.

[0078] In some embodiments, the heat treatment includes heating and maintaining the temperature of a mixture of the raw material for the silicone-based active particles and a metal doping source under a negative pressure environment.

[0079] In some embodiments, the degree of vacuum in the negative pressure environment is 0.001 Pa to 100 Pa, specifically 0.001, 10, 40, 60, 80, 100 or any value therebetween.

[0080] In some embodiments, the heating temperature is 1100 °C to 1600 °C, specifically 1100 °C, 1200 °C, 1300 °C, 1400 °C, 1500 °C or any value therebetween.

[0081] In some embodiments, the heat preservation time is 4 h to 30 h, specifically 4 h, 12 h, 20 h, 25 h, 30 h or any value therebetween.

[0082] In some embodiments, the cooling temperature is ≤ 100 °C, specifically 10 °C, 20 °C, 30 °C, 40 °C, 50 °C, 60 °C, 70 °C, 80 °C, 90 °C, 98 °C or any value therebetween.

[0083] Under the above heat treatment conditions, by introducing appropriate amounts of Mg element, Ca element and Cu element into the silicone-based active particles and uniformly distributing each element in the anode material under thermal action, it is more advantageous to more fully exert the improvement effect on the first cycle efficiency, conductivity and cycle performance of the anode material.

[0084] In some embodiments, the method further includes performing a pulverization treatment and / or a classification treatment on the active material obtained by cooling.

[0085] In some embodiments, the method employed in the pulverization treatment is any one or more of ball mill pulverization, airflow pulverization, crushing or spheroidization.

[0086] In some embodiments, in the classification treatment, materials with an average particle size D50 of 1 to 100 μm and a specific surface area of 1 to 120 m 2 / g are selected.

[0087] In some embodiments, the active material obtained by first cooling is subjected to a grinding process, and then further subjected to a classification process.

[0088] Grinding and classification processes are advantageous in obtaining anode materials with appropriate particle size and specific surface area, thereby simplifying material manufacturing and further reducing SEI film formation during the initial charge-discharge cycle process, thereby improving the initial cloning efficiency of the anode material.

[0089] In some embodiments, the method further includes cooling the active material to obtain a negative electrode material by carbon coating.

[0090] In some embodiments, the active material obtained by sequentially cooling is subjected to grinding, classification, and coating treatments.

[0091] In some embodiments, the carbon coating treatment includes one of gas-phase carbon coating, liquid-phase carbon coating, or solid-phase carbon coating.

[0092] In some embodiments, the coating material used in the carbon coating treatment is a carbon material, which includes at least one of graphite, graphene, amorphous carbon, diamond-like carbon, carbon nanotubes, and carbon fibers.

[0093] In some embodiments, the coating thickness of the carbon coating treatment is 50 nm to 200 nm, specifically 50 nm, 100 nm, 150 nm, 200 nm, or any value in between.

[0094] In some embodiments, the carbon coating process involves placing the active material in a CVD furnace, injecting argon gas from the outside as a protective gas, injecting acetylene gas from the inside as a carbon source, heating to 800°C to decompose the acetylene, and coating the surface of the active material with amorphous carbon to obtain a negative electrode material.

[0095] In some embodiments, the mass content ratio of carbon material to active material is (1-20):(80-99), specifically 1:99, 1:80, 5:80, 10:80, 15:80, 20:80, or any ratio between these.

[0096] By coating the surface of the active material with the above-mentioned carbon material, the formation of an SEI film caused by direct contact between the active material and the electrolyte is reduced, which is advantageous in reducing excessive electrolyte consumption and deterioration of the material's cycle performance. Furthermore, by protecting the active material while providing good conductivity, the conductivity of the negative electrode material can be further improved, and a suitable carbon layer can be provided to reduce cracking due to the action of internal particle stress.

[0097] In a third aspect, the present application further proposes a lithium-ion battery comprising the above-described negative electrode material, or comprising a lithium-ion battery manufactured by employing the above-described manufacturing method. The lithium-ion battery proposed in this application has features such as high initial cloning efficiency, high conductivity, and excellent cycle performance.

[0098] The embodiments of this application will be further described below, divided into several examples. However, the embodiments of this application are not limited to the specific embodiments described below. Appropriate modifications can be made without altering the sovereign right.

[0099] Example 1 Manufacturing of negative electrode materials (1) Preparation of active material: 5 kg of SiO, 0.48 kg of Mg, 0.2 kg of Ca, and 0.01 kg of Cu were taken, mixed for 30 minutes, and then placed in a vacuum furnace. Under a vacuum of 1 Pa, the mixture was heated to 1350°C and maintained for 20 hours to generate SiO vapor, Mg vapor, Ca vapor, and Cu vapor in the furnace. After uniformly mixing the vapors, the mixture was condensed to below 100°C to obtain 4 kg of active material. The active material contained silicone, silicone oxide, calcium silicate, magnesium silicate, and copper silicide. The Si crystallite size was calculated as 6 nm using XRD test spectroscopy and Scherrer equation.

[0100] (2) Powdering treatment: Take 3 kg of the active material produced in (1) above, and subject it to crushing, ball milling, classification, etc., to an average particle size D50 of approximately 4 μm and a specific surface area of ​​30 m². 2 It was controlled to / g.

[0101] (3) Carbon coating treatment: The active material after the powdering treatment in (2) above was placed in a CVD furnace, argon gas was injected from the outside as a protective gas, and acetylene gas was injected from the inside as a carbon source. The furnace was heated to 800°C to decompose the acetylene, coating the surface of the active material with 5% carbon to obtain the anode material. Here, the carbon material is amorphous carbon, and the pH value of the anode material is 8.5.

[0102] An inductively coupled plasma emission spectrometer was used to perform elemental quantitative analysis on the anode material manufactured in Example 1, and the detection results and the m calculated based on the detection results were obtained. Ca / m Mg and m Cu / m Mg This is shown in Table 1.

[0103] Then, electrochemical performance tests were performed on the anode material manufactured in Example 1. Please refer to Tables 2 and 3 for the test results.

[0104] Example 2 Manufacturing of negative electrode materials (1) Production of active material: 3 kg of silicone powder, 6 kg of SiO2, 3 kg of calcined copper-stained dolomite, and 3 kg of Mg were taken and mixed for 30 minutes, then placed in a vacuum furnace and heated to 1350°C under a vacuum of 1 Pa, and kept warm for 20 hours to generate SiO vapor, Mg vapor, Ca vapor, and Cu vapor in the furnace. After uniformly mixing the vapors, the mixture was condensed to below 100°C to obtain 4 kg of active material.

[0105] (2) Powdering treatment: Take 3 kg of the active material produced in (1) above, and subject it to crushing, ball milling, classification, etc., to an average particle size D50 of approximately 4 μm and a specific surface area of ​​33 m².2 controlled to / g.

[0106] (3) Carbon coating treatment: The active material after the pulverization treatment in the above (2) was placed in a CVD furnace, argon gas was injected from the outside as a protective gas, acetylene gas was injected from the inside as a carbon source, heated to 800 °C to decompose acetylene, and 5% of carbon was coated on the surface of the active material to obtain a negative electrode material. Here, the carbon material is amorphous carbon, and the pH value of the negative electrode material is 8.9.

[0107] Elemental quantitative analysis was performed on the negative electrode material obtained by manufacturing in Example 2 using an inductively coupled plasma optical emission spectrometer, and the detection results and m Ca / m Mg and m Cu / m Mg are as shown in Table 1.

[0108] Then, an electrochemical performance test was performed on the negative electrode material obtained by manufacturing in Example 2. For the test results, please refer to Table 2 and Table 3.

[0109] Example 3 Manufacture of negative electrode material (1) Manufacture of active material: 5 kg of SiO, 0.5 kg of Mg, 0.8 kg of Ca and 0.1 kg of Cu were taken, mixed for 30 min and then put into a vacuum furnace, heated to 1350 °C under a vacuum condition of 1 Pa, kept warm for 20 h, SiO vapor, Mg vapor, Ca vapor and Cu vapor were generated in the furnace, and after uniformly mixing the vapors, condensed to below 100 °C to obtain 4 kg of active material.

[0110] (2) Pulverization treatment: 3 kg of the active material obtained by manufacturing in the above (1) was taken, and treatments such as crushing, ball milling and classification were performed on it, and its average particle size D50 was controlled to about 4 μm and the specific surface area to 28 m 2 / g.

[0111] (3) Carbon coating treatment: The active material after the powdering treatment in (2) above was placed in a CVD furnace, argon gas was injected from the outside as a protective gas, and acetylene gas was injected from the inside as a carbon source. The furnace was heated to 800°C to decompose the acetylene, coating the surface of the active material with 5% carbon to obtain the anode material. Here, the carbon material is amorphous carbon, and the pH value of the anode material is 8.6.

[0112] An inductively coupled plasma emission spectrometer was used to perform elemental quantitative analysis on the negative electrode material manufactured in Example 3, and the detection results and the m calculated based on the detection results were obtained. Ca / m Mg and m Cu / m Mg This is shown in Table 1.

[0113] Then, electrochemical performance tests were performed on the negative electrode material manufactured in Example 3. Please refer to Tables 2 and 3 for the test results.

[0114] Example 4 Manufacturing of negative electrode materials (1) Production of active material: 5 kg of SiO, 0.5 kg of Mg, 0.7 kg of Ca, and 0.01 kg of Cu were taken, mixed for 30 minutes, and then placed in a vacuum furnace. Under a vacuum of 1.5 Pa, the mixture was heated to 1350°C and kept warm for 20 hours to generate SiO vapor, Mg vapor, Ca vapor, and Cu vapor in the furnace. After uniformly mixing the vapors, the mixture was condensed to below 100°C to obtain 4 kg of active material.

[0115] (2) Powdering treatment: 3 kg of the active material obtained in (1) above is taken and subjected to crushing, ball milling, classification, etc., to an average particle size D50 of approximately 4 μm and a specific surface area of ​​31 m². 2 It was controlled to / g.

[0116] (3) Carbon coating treatment: The active material after the powdering treatment in (2) above was placed in a CVD furnace, argon gas was injected from the outside as a protective gas, and acetylene gas was injected from the inside as a carbon source. The furnace was heated to 800°C to decompose the acetylene, coating the surface of the active material with 5% carbon to obtain the anode material. Here, the carbon material is amorphous carbon, and the pH value of the anode material is 8.6.

[0117] An inductively coupled plasma emission spectrometer was used to perform elemental quantitative analysis on the negative electrode material manufactured in Example 4, and the detection results and the m calculated based on the detection results were obtained. Ca / m Mg and m Cu / m Mg This is shown in Table 1.

[0118] Then, electrochemical performance tests were performed on the anode material manufactured in Example 4. Please refer to Tables 2 and 3 for the test results.

[0119] Example 5 Manufacturing of negative electrode materials (1) Production of active material: 5 kg of SiO, 0.5 kg of Mg, 1.5 kg of Ca, and 0.06 kg of Cu were taken, mixed for 30 minutes, and then placed in a vacuum furnace. Under a vacuum of 1 Pa, the mixture was heated to 1350°C and kept warm for 20 hours to generate SiO vapor, Mg vapor, Ca vapor, and Cu vapor in the furnace. After uniformly mixing the vapors, the mixture was condensed to below 100°C to obtain 4 kg of active material.

[0120] (2) Powdering treatment: Take 3 kg of the active material produced in (1) above, and subject it to crushing, ball milling, classification, etc., to an average particle size D50 of approximately 4 μm and a specific surface area of ​​26 m². 2 It was controlled to / g.

[0121] (3) Carbon coating treatment: The active material after the powdering treatment in (2) above was placed in a CVD furnace, argon gas was injected from the outside as a protective gas, and acetylene gas was injected from the inside as a carbon source. The furnace was heated to 800°C to decompose the acetylene, coating the surface of the active material with 5% carbon to obtain the anode material. Here, the carbon material is amorphous carbon, and the pH value of the anode material is 8.8.

[0122] An inductively coupled plasma emission spectrometer was used to perform elemental quantitative analysis on the negative electrode material manufactured in Example 5, and the detection results and the m calculated based on the detection results were obtained. Ca / m Mg and m Cu / m Mg This is shown in Table 1.

[0123] Then, electrochemical performance tests were performed on the anode material manufactured in Example 5. Please refer to Tables 2 and 3 for the test results.

[0124] Example 6 Manufacturing of negative electrode materials (1) Production of active material: 5 kg of SiO, 0.48 kg of Mg, 0.8 kg of Ca, and 0.4 kg of Cu were taken, mixed for 30 minutes, and then placed in a vacuum furnace. Under a vacuum of 1 Pa, the mixture was heated to 1350°C and kept warm for 20 hours to generate SiO vapor, Mg vapor, Ca vapor, and Cu vapor in the furnace. After uniformly mixing the vapors, the mixture was condensed to below 100°C to obtain 4 kg of active material.

[0125] (2) Powdering treatment: 3 kg of the active material obtained in (1) above is taken and subjected to crushing, ball milling, classification, etc., to an average particle size D50 of approximately 4 μm and a specific surface area of ​​37 m². 2 It was controlled to / g.

[0126] (3) Carbon coating treatment: The active material after the powdering treatment in (2) above was placed in a CVD furnace, argon gas was injected from the outside as a protective gas, and acetylene gas was injected from the inside as a carbon source. The furnace was heated to 800°C to decompose the acetylene, coating the surface of the active material with 5% carbon to obtain the anode material. Here, the carbon material is amorphous carbon, and the pH value of the anode material is 9.

[0127] An inductively coupled plasma emission spectrometer was used to perform elemental quantitative analysis on the negative electrode material manufactured in Example 6, and the detection results and the m calculated based on the detection results were obtained. Ca / m Mg and m Cu / m Mg This is shown in Table 1.

[0128] Then, electrochemical performance tests were performed on the anode material manufactured in Example 6. Please refer to Tables 2 and 3 for the test results.

[0129] Example 7 Manufacturing of negative electrode materials (1) Production of active material: 5 kg of SiO, 0.48 kg of Mg, 0.2 kg of Ca, and 0.01 kg of Cu were taken, mixed for 30 minutes, and then placed in a vacuum furnace. Under a vacuum of 0.001 Pa, the mixture was heated to 1100°C and maintained at that temperature for 30 hours to generate SiO vapor, Mg vapor, Ca vapor, and Cu vapor in the furnace. After uniformly mixing the vapors, the mixture was condensed to below 100°C to obtain 4 kg of active material.

[0130] (2) Powdering treatment: Take 3 kg of the active material produced in (1) above, and subject it to crushing, ball milling, classification, etc., to an average particle size D50 of about 1 μm and a specific surface area of ​​120 m². 2 It was controlled to / g.

[0131] (3) Carbon coating treatment: The active material after the powdering treatment in (2) above was placed in a CVD furnace, argon gas was injected from the outside as a protective gas, and acetylene gas was injected from the inside as a carbon source. The furnace was heated to 750°C to decompose the acetylene and coat the surface of the active material with 1% carbon to obtain the anode material. Here, the carbon material contains amorphous carbon, the thickness of the carbon layer is 50 nm, and the pH value of the anode material is 8.

[0132] An inductively coupled plasma emission spectrometer was used to perform elemental quantitative analysis on the anode material manufactured in Example 7, and the detection results and the m calculated based on the detection results were obtained. Ca / m Mg and m Cu / m Mg This is shown in Table 1.

[0133] Then, electrochemical performance tests were performed on the anode material manufactured in Example 7. Please refer to Tables 2 and 3 for the test results.

[0134] Example 8 Manufacturing of negative electrode materials (1) Production of active material: 5 kg of SiO, 0.48 kg of Mg, 0.2 kg of Ca, and 0.01 kg of Cu were taken, mixed for 30 minutes, and then placed in a vacuum furnace. Under a vacuum of 100 Pa, the mixture was heated to 1600°C and kept warm for 4 hours to generate SiO vapor, Mg vapor, Ca vapor, and Cu vapor in the furnace. After uniformly mixing the vapors, the mixture was condensed to below 100°C to obtain 4 kg of active material.

[0135] (2) Powdering treatment: Take 3 kg of the active material produced in (1) above, and subject it to crushing, ball milling, classification, etc., to an average particle size D50 of about 100 μm and a specific surface area of ​​1 m². 2 It was controlled to / g.

[0136] (3) Carbon coating treatment: The active material after the powdering treatment in (2) above was placed in a CVD furnace, argon gas was injected from the outside as a protective gas, and acetylene gas was injected from the inside as a carbon source. The furnace was heated to 850°C to decompose the acetylene and coat the surface of the active material with 20% carbon to obtain the anode material. Here, the carbon material contains amorphous carbon, the thickness of the carbon layer is 200 nm, and the pH value of the anode material is 10.

[0137] An inductively coupled plasma emission spectrometer was used to perform elemental quantitative analysis on the negative electrode material manufactured in Example 8, and the detection results and the m calculated based on the detection results were obtained. Ca / m Mg and m Cu / m Mg This is shown in Table 1.

[0138] Then, electrochemical performance tests were performed on the negative electrode material manufactured in Example 8. Please refer to Tables 2 and 3 for the test results.

[0139] Comparative Example 1 The difference from Example 1 is that the raw materials added in step (1) are 5 kg of SiO and 0.5 kg of Mg.

[0140] Comparative Example 2 The difference from Example 1 is that the raw materials added in step (1) are 5 kg of SiO, 0.5 kg of Mg, and 0.2 kg of Ca.

[0141] Comparative Example 3 The difference from Example 1 is that the raw materials added in step (1) are 5 kg of SiO, 0.5 kg of Mg, 0.2 kg of Ca, and 0.2 kg of Cu.

[0142] Comparative Example 4 The difference from Example 1 is that the raw materials added in step (1) are 5 kg of SiO, 0.5 kg of Mg, 0.8 kg of Ca, and 0.01 kg of Cu.

[0143] Comparative Example 5 The difference from Example 1 is that the raw materials added in step (1) are 5 kg of SiO, 0.5 kg of Mg, and 0.6 kg of Cu.

[0144] Test method: 1. Elemental content: Elemental quantitative analysis of the anode material was performed using an inductively coupled plasma atomic emission spectrometer and an oxygen-nitrogen-hydrogen tester.

[0145] 2. Si crystallite size: An X-ray diffractometer was used to perform scanning tests on the negative electrode material within the range of 10 to 90 degrees, and the Si crystallite size was calculated using the Scherrer formula.

[0146] 3. Thickness of the carbon material: The thickness of the carbon material was confirmed by using an ion mill to perform polishing and cutting treatment on the negative electrode material, and then observing the cross-section of the negative electrode material using a scanning electron microscope.

[0147] 4. pH value: The pH value of the negative electrode material was obtained by testing it using a Mettler-Toledo pH meter.

[0148] 5. Average particle size D50: Obtained by particle size analysis of the anode material using a Malvern Panalytical Mastersizer 3000 laser particle size distribution analyzer, and represents the cumulative volume distribution.

[0149] 6. Specific surface area: Obtained by analyzing the specific surface area of ​​the anode material using a McBee table Tristar 3020 with nitrogen gas as the adsorption / desorption gas.

[0150] 7. Powder Conductivity: The volume resistivity of the negative electrode material powder was tested using the four-probe method. The resistance of the powder was tested at five pressure points: 4KN, 8KN, 12KN, 16KN, and 20KN, using the instrument. The computer then automatically calculated the conductivity and resistivity of the negative electrode material powder. The data in Appendix 3 represents the conductivity at a pressure of 20KN.

[0151] 8. Electrical performance test: The button battery was assembled according to the instructions in BTRTC / ZY / 01-020 "Button Battery Manufacturing Method and Operation Manual," specifically as follows: the negative electrode material, conductive carbon black and polyacrylic adhesive, were dissolved in deionized water in a mass percentage of 75:15:10, and then uniformly dispersed in it using a high-speed disperser. The stirring parameters were first stirred at a rotation speed of 800 r / min for 20 s, and then stirred at a rotation speed of 2000 r / min for 5 min. Then, the copper foil surface is wiped with a dust-free cloth soaked in anhydrous ethanol to remove oil stains, and the slurry is uniformly applied to the copper foil at a speed of 20 mm / s using an automatic coating machine equipped with a 200 μm coater. After drying for 0.5 hours in a 95 °C blast drying oven, it is transferred to a vacuum drying oven and dried for 8 hours at 130 °C. It is then punched out to form electrode plates with a diameter of φ=16 mm, and after weight packaging, it is transferred to an argon gas-filled glove box for battery assembly. Here, metallic lithium sheets are used for the electrodes, the separator is a PP-PE-PP composite film with a diameter of 19.2 mm, the electrolyte component ratio is EC / EMC / DMC=1 / 1 / 1, and the lithium salt (LiPF6) concentration is 1.05 mol / L.

[0152] (1) Lithium storage capacity: Under room temperature conditions, the device is charged with a constant current of 0.1C, and the charging voltage is limited to 0.005V to 1.5V. The corresponding capacity is the lithium storage capacity.

[0153] (2) Lithium release capacity: Discharge at a constant current of 0.1C under room temperature conditions, limiting the discharge voltage to 1.5V to 0.005V, and the corresponding capacity is the lithium release capacity.

[0154] (3) Initial cloning efficiency: This is the ratio of the lithium storage capacity obtained in the first charge to the lithium release capacity obtained in the first discharge, multiplied by 100%.

[0155] (4) Cycle performance: The negative electrode materials produced in the examples and comparative examples were manufactured as batteries and tested using a button battery charging / discharging device. In the first cycle, the battery was discharged to 0.01V at 0.1C, discharged to 0.01V by arithmetic decrease at 0.01C, discharged to 0.005V at 0.01C and charged to 1.5V at 0.1C. In the second cycle, the battery was discharged to 0.01V at 0.2C, discharged to 0.01V by arithmetic decrease at 0.02C, discharged to 0.005V at 0.02C and charged to 1.5V at 0.2C. In the third cycle... The battery was discharged to 0.01V at 0.5C, then discharged to 0.01V using an arithmetic decrease of 0.05C, discharged to 0.005V at 0.05C, and charged to 1.5V at 0.5C. From the 4th to the 50th cycle, the battery was discharged to 0.01V at 1C, then discharged to 0.01V using an arithmetic decrease of 0.1C, discharged to 0.005V at 0.1C, and charged to 1.5V at 1C. In the 51st cycle, the battery was discharged to 0.01V at 0.1C, then discharged to 0.01V using an arithmetic decrease of 0.01C, and discharged to 0.005V at 0.01C.

[0156] (5) Plate expansion rate: Under room temperature conditions, the thickness of the plates fabricated using a spiral micrometer is tested and recorded. The plates are then assembled into a battery, and a charge-discharge cycle is performed. After a certain number of cycles, the battery is disassembled, and the thickness of the plates is tested using a spiral micrometer. The ratio of the increase in thickness of the plates after the cycle compared to the plates before the cycle, to the thickness of the plates before the cycle, is the plate expansion rate.

[0157] Test results: The results of the elemental content tests for the negative electrode materials produced in Examples 1-8 and Comparative Examples 1-5 are shown in Table 1 below. In the negative electrode materials, elements other than Ca, Mg, and Cu are Si, O, and C. The mass content of silicon is 24%-36%, the mass content of oxygen is 44%-59%, and the remainder is carbon.

[0158] Table 1 JPEG2026525448000002.jpg130167

[0159] The results of the electrical performance tests for the negative electrode materials manufactured in Examples 1-8 and Comparative Examples 1-5 are shown in Table 2 below.

[0160] Table 2 JPEG2026525448000003.jpg127166

[0161] The conductivity and cycle expansion performance test results for the negative electrode materials manufactured in Examples 1-8 and Comparative Examples 1-5 are shown in Table 3 below.

[0162] Table 3 JPEG2026525448000004.jpg135166

[0163] When analyzing Tables 1, 2, and 3 together, As can be seen from the comparison between Comparative Examples 1, 2, and 5 and Example 1, compared to negative electrode materials in which the active material contains only one or two of the elements Ca, Mg, and Cu, the active material of the negative electrode material of this application contains three elements simultaneously: Ca, Mg, and Cu. This is advantageous in reducing the volume expansion coefficient of the material and increasing the ratio of lithium release capacity to lithium storage capacity, and was able to comprehensively improve the initial cloning efficiency, conductivity, and cycle performance of the material. Here, compared to Example 1, the conductivity of Comparative Example 5 was relatively high, but its cycle expansion coefficient also increased significantly, and the application of the negative electrode material is relatively limited. The specific reason for this is that in Comparative Example 5, m Cu / m Mg By increasing the amount of copper silicide in the negative electrode material relatively significantly, the conductivity of the negative electrode material is improved, and m Ca / m MgThe reduction in magnesium silicate leads to an imbalance in the mixing ratio of magnesium silicate to calcium silicate in the anode material, reducing the structural stability of the anode material and resulting in a significant decrease in the cycle performance of the anode material. Examples 7 and 8 modified the manufacturing process of the coating layer, and since the content of element M remained within the scope of this application, the performance of the anode material did not significantly decrease, and the technical problems proposed by this application were still solved.

[0164] As can be seen from the comparison between Comparative Examples 3-4 and Examples 1-4, the mass content ratios of calcium, copper, and magnesium in the manufactured negative electrode material are all 0. <m Ca / m Mg Satisfying <0.1, and 0 <m Cu / m Mg When <0.01, the volume expansion coefficient of the negative electrode material and the ratio of lithium release capacity to lithium storage capacity can be improved, and the initial cloning efficiency, conductivity, and cycle performance of the material can be comprehensively enhanced without any degradation of one or more of the performances due to imbalances in elemental distribution. Here, compared to Examples 1 to 4, the conductivity of Comparative Example 3 was relatively high, but its cycle expansion coefficient also increased significantly, which severely limited the application of the negative electrode material. The reason for this is that in Comparative Example 3, m Cu / m Mg While the conductivity of the anode material was improved by increasing the copper silicide content in the anode material, the absence of calcium significantly reduced the structural stability of the anode material, and the cycle expansion rate clearly increased.

[0165] The foregoing are merely preferred embodiments of this application and are not intended to limit it. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should all be included within the scope of protection of this application.

Claims

1. A negative electrode material comprising an active material, wherein the active material comprises Si element, O element, and metal M element, and the metal M comprises Mg, Ca, and Cu. In the aforementioned negative electrode material, the mass content of Mg element is m Ｍｇ Therefore, the mass content of element Ca is m Ｃａ Therefore, the mass content of Cu is m Ｃｕ Therefore, 0 < m Ｃａ / m Ｍｇ <0.1, 0 < m Ｃｕ / m Ｍｇ A negative electrode material characterized by having a value of <0.

01.

2. The aforementioned negative electrode material is (1) In the active material, Mg, Ca and Cu are all uniformly distributed, (2) 0 < m Ｍｇ <25% and (3) 0 < m Ｃａ < 10% and (4) 0 < m Ｃｕ The negative electrode material according to claim 1, characterized in that it has at least one of the following characteristics: <0.5%.

3. The aforementioned negative electrode material is (1) The mass content of the silicon element in the negative electrode material is 24% to 36%, (2) The anode material according to claim 1, characterized in that it has at least one of the following features: the mass content of the element oxygen in the anode material is 44% to 59%.

4. The aforementioned negative electrode material is (1) In the active material, the Si element exists in the form of elemental silicon and / or silicon oxide, and the Si crystallite size in the elemental silicon and / or silicon oxide is ≤ 15 nm. (2) The negative electrode material according to claim 1, characterized in that the active material has at least one of the following characteristics: the Si element exists in at least one form from amorphous silicone, crystalline silicone, silicone oxide, silicone alloy, and composite of crystalline silicone and amorphous silicone.

5. The active material includes a silicon oxide, and the general formula of the silicon oxide is SiO ｘ The negative electrode material according to claim 1, characterized in that 0 < x ≤ 2.

6. The negative electrode material according to claim 1, characterized in that the form of the metal M includes at least one of a silicate of M, an oxide of M, and a silicide of M.

7. The negative electrode material according to claim 6, characterized in that the active material comprises at least one of calcium silicate, magnesium silicate, and copper silicide.

8. The aforementioned negative electrode material is (1) 0.028 ≤ m Ｃａ / m Ｍｇ ≤0.099, 0.0008 ≤m Ｃｕ / m Ｍｇ The fact that ≤ 0.0099, (2) 5% ≤ m Ｍｇ The fact that it is ≤15%, (3) 0.2% ≤ m Ｃａ The fact that it is ≤0.8%, (4) 0.007% ≤ m Ｃｕ The negative electrode material according to claim 2, characterized in that it has at least one of the following features: ≤0.08%.

9. The negative electrode material according to claim 1 or 2, further comprising a carbon material, wherein the carbon material is located on the surface of at least a portion of the active material.

10. The aforementioned negative electrode material is (1) The carbon material includes at least one of graphite, graphene, amorphous carbon, diamond-like carbon, carbon nanotubes, and carbon fibers. (2) The carbon material forms a carbon layer on the surface of the active material, (3) The carbon material forms a carbon layer on the surface of the active material, and the thickness of the carbon layer is 50 nm to 200 nm. (4) The anode material according to claim 9, characterized in that it has at least one of the following features: the mass content of the element carbon in the anode material is 1% to 20%.

11. The aforementioned negative electrode material is (1) The pH value of the negative electrode material is 8 to 10, (2) The average particle size D50 of the negative electrode material is 1 μm to 100 μm, (3) The specific surface area of ​​the negative electrode material is 1 m ２ / g to 120m ２ The fact that it is / g, (4) The negative electrode material according to claim 1, characterized in that it has at least one of the following features: the conductivity of the negative electrode material is 0.5 S / cm to 7 S / cm.

12. A method for manufacturing a negative electrode material, The process includes the steps of mixing a raw material for silicone-based active particles with a metal doping source containing element M, heat-treating the mixture, mixing the resulting vapor, and then cooling to obtain an active material, wherein the negative electrode material contains the active material, the active material contains element Si, element O, and metal element M, the metal M contains Mg, Ca, and Cu, and the mass content of element Mg in the negative electrode material is m Ｍｇ Therefore, the mass content of element Ca is m Ｃａ Therefore, the mass content of Cu is m Ｃｕ Therefore, 0 < m Ｃａ / m Ｍｇ <0.1, 0 < m Ｃｕ / m Ｍｇ A method for manufacturing a negative electrode material, characterized in that it is <0.

01.

13. The aforementioned manufacturing method is (1) The mass ratio of the metal doping source to the raw material of the silicone-based active particles is (1 to 35):100, (2) The metal doping source includes at least one of the elemental metal M and a compound containing metal M, (3) The raw materials for the silicone-based active particles are Si, SiO ｙ and SiO ２ A mixture of, SiO ｙ A mixture of Si and SiO ２ It contains at least one of the following mixtures, and 0 < y < 2, (4) The amount of molars of element M in the metal doping source is n Ｍ Therefore, the molar amount of Si in the raw material of the silicone-based active particles is n Ｓｉ and n Ｍ :n Ｓｉ = (0.02 to 0.62): 1, (5) The amount of molars of element M in the metal doping source is n Ｍ Therefore, 0 < n Ｃａ / n Ｍｇ <1.8, 0<n Ｃｕ / n Ｍｇ The manufacturing method according to claim 12, characterized by including at least one of the following features: <0.

3.

14. The manufacturing method according to claim 12 or 13, further comprising carbon coating the active material obtained by cooling to obtain a negative electrode material.

15. A lithium-ion battery characterized by comprising a negative electrode material according to any one of claims 1 to 11, or a negative electrode material obtained by employing a manufacturing method according to any one of claims 12 to 14.

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