Lithium replenisher and method for manufacturing the same, positive electrode slurry, and battery

Abstract

This application discloses a lithium replenisher, a method for producing the same, a positive electrode slurry, and a battery, wherein the lithium replenisher has the chemical formula Li x M1 y M2 1-y Satisfying O6, where 6 ≤ x ≤ 8, and 0

Description

Technical Field

[0001] The present disclosure relates to the technical field of batteries, and specifically, to a lithium replenisher and its manufacturing method, a positive electrode slurry, and a battery.

Background Art

[0002] In the first charging process of a lithium-ion battery, a solid electrolyte interface film (SEI) is formed at the negative electrode interface, which causes an irreversible loss to the battery capacity, thereby reducing the energy density of the lithium-ion battery. According to the lithium replenishment technology, the capacity loss in the process of forming the SEI film can be effectively alleviated. As the lithium replenishment technology, there are mainly two methods: lithium replenishment on the positive electrode side and lithium replenishment on the negative electrode side. Here, in the lithium replenishment technology on the negative electrode side, a metallic lithium material needs to be used, and there are problems such as a complicated process and high requirements for the environment. The lithium replenishment technology on the positive electrode side has high safety and compatibility, so its feasibility is also high. However, it is considered that there are also many problems to be solved in the actual production and application process of lithium replenishment on the positive electrode side.

Summary of the Invention

Means for Solving the Problems

[0003] In the first aspect of the present application, the present application provides a chemical formula Li x M1 y M2 1-yA kernel that satisfies O6, where 6 ≦ x ≦ 8 and 0 < y < 1, and M1 is at least one of Zr, Nb, Sb, Bi, Ru, Ta, Sn, Hf, Ir, Pr, Pt, Np, and M2 is at least one of W, Ge, Ca, Ce, K, Ta, and a coating layer that is located on at least a part of the surface of the kernel and contains a lithium-containing metal oxide and a carbon material. The lithium-containing metal oxide satisfies the chemical formula LiaMbOc, where 1.8 ≦ a ≦ 2, 0.7 ≦ b ≦ 1.1, and 2.8 ≦ c ≦ 3, and M contains Ti and / or Zr. The peak intensity of the diffraction peak for X-rays when the 2θ diffraction angle is within the range of 20.1° to 20.3° is S1, and the peak intensity of the diffraction peak for X-rays when the 2θ diffraction angle is within the range of 17° to 17.3° is S2, and S1 / S2 is 0.02 to 0.05. A lithium supplement is proposed. Thereby, the lithium supplement has a high lithium supplement capacity, a high lithium ion migration rate, and excellent processing performance.

[0004] In some embodiments, the mass fraction of the lithium-containing metal oxide in the lithium supplement is 0.01% to 0.1%, and / or the mass fraction of the carbon material in the lithium supplement is 0.01% to 0.5%. Thereby, the lithium supplement has a high lithium supplement capacity.

[0005] In some embodiments, the lattice constant of the kernel satisfies a = b, a ≠ c, and c / a is 2 to 3. Thereby, the lithium ion migration rate of the lithium supplement can be increased.

[0006] In some embodiments, a is 0.4 nm to 0.7 nm and c is 1.4 nm to 1.6 nm. Thereby, the lithium ion migration rate of the lithium supplement can be further increased.

[0007] In some embodiments, the Dv50 particle size of the kernel is 1 μm to 10 μm, and / or the thickness of the coating layer is 50 nm to 500 nm. Thereby, the coating layer can improve the storage performance of the lithium supplement, enhance the conductivity of the lithium supplement, and contribute to the full exertion of the lithium supplement function by the lithium supplement.

[0008] In some embodiments, the kernel is Li8Zr 0.9 W 0.1 O6, Li7Nb 0.8 Ta 0.2 O6, Li7Sb 0.9 Ta 0.1 O6, Li7Ru 0.7 W 0.2 Ce 0.1 O6, Li8Sn 0.9 Ca 0.1 O6, Li8Hf 0.7 W 0.2 Ca 0.1 O6, Li8Ir 0.6 W 0.2 Ce 0.2 O6, Li8Pr 0.5 W 0.3 Ca 0.2 O6, Li8Pt 0.7 W 0.2 Ca 0.1 and includes at least one of O6. Thereby, the lithium supply capacity of the lithium supply agent can be effectively improved, and the decomposition potential of the lithium supply agent can be reduced.

[0009] In some embodiments, the graphitization degree of the carbon material is 60% or more. Thereby, the conductivity of the lithium supplement can be further improved.

[0010] In a second aspect of the present application, the present application proposes a method for producing the lithium replenisher described above, comprising the steps of: obtaining a kernel by performing a first sintering treatment on a lithium source, an M1 source, and an M2 source in an oxygen-containing atmosphere; and obtaining the lithium replenisher by performing a second sintering treatment on the kernel, an M source, and a carbon source in an inert atmosphere to form a coating layer on at least a portion of the surface of the kernel. This makes it possible to obtain a lithium replenisher having the excellent lithium replenishment performance described above in a simple manner.

[0011] In some embodiments, the lithium source comprises at least one of lithium carbonate, lithium hydroxide, and lithium oxide, and / or the M1 source comprises at least one of the oxide of M1, the chloride of M1, the nitrate of M1, and the hydroxide of M1, and / or the M2 source comprises at least one of the oxide of M2, the chloride of M2, the nitrate of M2, and the hydroxide of M2. This contributes to the formation of a kernel with a high lithium replenishment capacity.

[0012] In some embodiments, the temperature of the first sintering treatment is 700°C to 1200°C, and the duration of the first sintering treatment is 8 hours to 24 hours. This contributes to obtaining pure phase kernel particles with appropriate particle sizes.

[0013] In some embodiments, the M source comprises at least one of zirconium propoxide, zirconium oxide, zirconium nitrate, zirconium oxychloride, lithium zirconate, zirconium chloride, titanium oxide, titanium tetrachloride, titanium nitrate, and titanium alkoxide, and / or the carbon source comprises at least one of glucose, starch, sucrose, and graphite. This contributes to the formation of lithium-containing metal oxides on the surface of the kernel.

[0014] In some embodiments, the temperature of the second sintering treatment is 400°C to 800°C, and the duration of the second sintering treatment is 6H to 10H. This contributes to the formation of lithium-containing metal oxides and carbon materials in the coating layer.

[0015] In some embodiments, the process further includes a step of mixing the kernel, the M source, and the carbon source in a solvent and drying them before the second sintering process. This contributes to improving the uniformity of the coating by the coating layer.

[0016] In some embodiments, the solvent comprises at least one of ethanol and isopropanol, and / or the drying treatment comprises at least one of spray drying, freeze-drying, and flash drying. This contributes to improving the uniformity of the coating by the coating layer.

[0017] In a third aspect of this application, the present application proposes a positive electrode slurry comprising the lithium replenisher described above, or a lithium replenisher manufactured by the method described above. The positive electrode slurry thereby possesses all the constituent elements and advantages of the lithium replenisher and the method for manufacturing the lithium replenisher described above. Further explanation is omitted here.

[0018] In some embodiments, the viscosity of the positive electrode slurry is between 1000 mPa·s and 8000 mPa·s. This contributes to improving the processing performance of the positive electrode slurry.

[0019] In a fourth aspect of the present application, the present application proposes a battery comprising a positive electrode tab including a positive electrode current collector and a positive electrode active material layer located on at least one side of the positive electrode current collector, wherein the positive electrode active material layer is manufactured from the positive electrode slurry described above. The battery thus possesses all the constituent requirements and advantages of the positive electrode slurry described above. Further explanation is omitted here. [Brief explanation of the drawing]

[0020] The above-mentioned and / or additional aspects and advantages of this application will become apparent and readily understandable from the description of the embodiments with reference to the following accompanying drawings. [Figure 1] This is a scanning electron microscope image of the lithium replenisher in Example 1 of the present invention. [Figure 2] These are X-ray diffraction patterns of the lithium replenisher in Example 1 and Comparative Example 5 of this application. [Figure 3] This is a charge-discharge graph after a battery has been manufactured using the lithium replenisher in Example 1 of the present invention. [Modes for carrying out the invention]

[0021] The embodiments of this application will be described in detail below. Examples of the embodiments described are shown in the accompanying drawings, but unnecessary descriptive details may be omitted. For example, details of publicly known matters may be omitted, or redundant descriptions of the same structure may be omitted. This is intended to avoid making the following description unnecessarily verbose and to make it easily understandable to those skilled in the art. The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this application and are not intended to limit the subject matter described in the claims.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art, and the technical terms used herein are solely for the purpose of describing specific embodiments and are not intended to limit the application. Furthermore, unless otherwise described, the values ​​of each parameter referred to herein may be measured by various measurement methods commonly used in the art (for example, by the methods provided in the embodiments of this application).

[0023] The technical terms "includes," "equip," and any variations thereof in the specification and claims of this application constitute open expressions, that is, they include the content shown in this application, but do not exclude the content of other embodiments.

[0024] In this description, regardless of whether the words "approximately" or "about" are used, all figures disclosed herein are approximations. The numerical values ​​indicated by each figure may vary by 10% or less, or by a reasonable amount that would be recognized by a person skilled in the art, such as 1%, 2%, 3%, 4%, or 5%.

[0025] Unless otherwise specifically described, all embodiments and optional embodiments in this application can be combined to form new technical inventions.

[0026] Unless otherwise specified, all constituent elements and optional constituent elements in this application can be combined to form new technical solutions.

[0027] Related technologies include lithium replenishers for the positive electrode, such as binary lithium-containing compounds like Li2O, Li2O2, and Li3N, and ternary lithium-containing compounds like Li2NiO2, Li6CoO4, and Li5FeO4. Binary lithium-containing compounds have poor stability in atmospheric environments and are difficult to apply to industrial applications. Ternary lithium-containing compounds are more stable than binary lithium-containing compounds, but they have the drawback of being highly alkaline on the surface and having a high decomposition potential. Specifically, when a lithium replenisher is added to a positive electrode slurry, the strongly alkaline surface of the lithium replenisher causes a lithium deposition reaction, strengthening the alkalinity of the positive electrode slurry. This significantly increases the viscosity of the positive electrode slurry, which can lead to the formation of a jelly-like slurry, making it impossible to meet the application requirements. If the decomposition potential of the lithium replenisher is too high, a high voltage must be applied during the initial charging process of the battery to ensure that the lithium replenishment capacity in the lithium replenisher is sufficiently released. If the voltage applied during the initial charging process is too high, irreversible structural changes occur in the positive electrode active material in the positive electrode active material layer. This reduces the lithium desorption sites in the positive electrode active material, lowering the battery's energy density. If the voltage applied during the initial charging process is too low, the lithium replenishment capacity of the lithium replenisher cannot be sufficiently released, resulting in a reduced lithium replenishment effect by the lithium replenisher.

[0028] In this application, the elemental composition of the lithium replenisher is optimized, and by adding doping elements to a ternary lithium-containing lithium replenisher as a base, the lithium ion transition rate of the lithium replenisher kernel can be further increased. Specifically, the kernel of the lithium replenisher has the chemical formula Li x M1 y M2 1-yIt satisfies O6, provided that 6 ≤ x ≤ 8 and 0 < y < 1. Here, since the theoretical capacity of the ternary lithium-containing compound containing the M1 element is high, the lithium replenishment capacity of the lithium replenisher can be effectively increased. The M2 element has a relatively smaller lithium replenishment capacity that can be provided compared to the M1 element, but due to its ionic radius being even larger than that of the M1 element, the doping of the M2 element contributes to the rapid insertion and extraction of lithium ions due to the interlayer distance between the layered structures in the kernel. Thereby, the kernel of the lithium replenisher has a high capacity, a high lithium replenishment capacity, and a high lithium ion migration rate. Furthermore, due to the alkaline surface of the kernel of the above-described lithium replenisher, there may be a problem such as the positive electrode slurry becoming a gel. Therefore, by forming a coating layer containing a lithium-containing metal oxide and a carbon material on the surface of the kernel of the above-described lithium replenisher, the lithium-containing metal oxide in the coating layer can effectively suppress the reaction of the kernel with moisture, carbon dioxide, etc. in the air to generate lithium hydroxide or lithium carbonate impurities. However, since the conductivity of the lithium-containing metal oxide is not good, by further adding an appropriate amount of carbon material to the coating layer, the conductivity of the coating layer is effectively improved, and further, the electron conductivity of the surface of the lithium replenisher is improved to improve the transport path of lithium ions and electrons of the lithium replenisher.

[0029] The lithium replenisher described above exhibits a characteristic diffraction peak for X-rays when the 2θ diffraction angle is in the range of 20.1° to 20.3°, indicating that the lithium-containing metal oxide in the coating layer has a tetragonal structure (110 crystal plane). However, the lithium replenisher described above exhibits a characteristic diffraction peak for X-rays when the 2θ diffraction angle is in the range of 17° to 17.3°, indicating that the kernel of the lithium replenisher has a hexagonal structure (101 crystal plane). Furthermore, when the 2θ diffraction angle of the lithium replenisher is within the range of 20.1° to 20.3°, the peak intensity of the diffraction peak for X-rays is S1, and when the 2θ diffraction angle of the lithium replenisher is within the range of 17° to 17.3°, the peak intensity of the diffraction peak for X-rays is S2. When S1 / S2 is between 0.02 and 0.05, the phase ratio between the hexagonal structured lithium replenisher kernel and the tetragonal structured coating layer is appropriate. In this case, the hexagonal structured kernel has a high lithium ion transport rate, which is advantageous for sufficient release of lithium ions in the kernel. Moreover, the tetragonal structured lithium-containing metal oxide has high structural stability, effectively suppressing the generation of impurities due to reactions between the kernel and water, carbon dioxide, etc., and simultaneously possesses good lithium insertion and deinsertion characteristics. Therefore, the influence of the surface coating layer formed by both the lithium-containing metal oxide and the carbon material on the lithium replenishment performance of the kernel is reduced, and the transport pathways for lithium ions and electrons in the lithium replenisher can be effectively improved.

[0030] In the first aspect of this application, the present application relates to the chemical formula Li x M1 y M2 1-yA kernel that satisfies O6, where 6 ≦ x ≦ 8 and 0 < y < 1, and M1 is at least one of Zr, Nb, Sb, Bi, Ru, Ta, Sn, Hf, Ir, Pr, Pt, Np, and M2 is at least one of W, Ge, Ca, Ce, K, Ta, and a coating layer located at least on a part of the surface of the kernel, the coating layer containing a lithium-containing metal oxide and a carbon material, the lithium-containing metal oxide satisfying the chemical formula LiaMbOc, where 1.8 ≦ a ≦ 2, 0.7 ≦ b ≦ 1.1, and 2.8 ≦ c ≦ 3, and M contains Ti and / or Zr, and when the diffraction angle of 2θ is within the range of 20.1° to 20.3°, the peak intensity of the diffraction peak for X-rays is S1, and when the diffraction angle of 2θ is within the range of 17° to 17.3°, the peak intensity of the diffraction peak for X-rays is S2, and S1 / S2 is 0.02 to 0.05, a lithium supplement is proposed. Thereby, the above lithium supplement has a high lithium supplement capacity and a high lithium ion migration rate. Here, since there is a stabilized tetragonal crystal structure coating layer on the surface of the hexagonal crystal structure kernel, when the ratio of S1 to S2 satisfies the above limiting conditions, the coating layer can effectively improve the stability of the kernel and reduce the increase in the viscosity of the cathode slurry due to the surface alkalinity of the kernel during the use process of the lithium supplement, and has excellent processing performance. When the above lithium supplement is applied to the technology of lithium supplement on the cathode side, during the charging process of the battery, the lithium supplement can sufficiently decompose and release active lithium ions, supplement the loss of active lithium due to the formation of the SEI film, and obtain the effect of improving the energy density and cycle life of the lithium battery.

[0031] As an example, x may be 6, 6.5, 7, 7.5 or 8.

[0032] As an example, y may be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, or 0.9.

[0033] As an example, a may be 1.8, 1.9 or 2.

[0034] For example, b may be 0.7, 0.8, 0.9, 1, or 1.1.

[0035] For example, c may be 2.8, 29, or 3.

[0036] For example, S1 / S2 may be 0.02, 0.03, 0.04, or 0.05.

[0037] In this application, the "peak intensity ratio of diffraction peaks" has the meaning known in the art and may be measured by instruments and methods known in the art. For example, it can be obtained by the following method: Using an automated X-ray diffractometer, analyze the physical phase and crystal structure, with an operating voltage of 40kV, an operating current of 250mA, using a means for continuous scanning, a scanning speed of 4° / min, a step length of 0.02°, and a scanning angle range of 10° to 80°.

[0038] In some embodiments, the mass fraction of the lithium-containing metal oxide in the lithium replenisher is 0.01% to 0.1%, and / or the mass fraction of the carbon material in the lithium replenisher is 0.01% to 0.5%.

[0039] For example, the mass fraction of the lithium-containing metal oxide in the lithium replenisher may be 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, or 0.1%.

[0040] When the mass fraction of the lithium-containing metal oxide in the lithium replenisher is within the range described above, the lithium-containing metal oxide in the coating layer can exhibit the advantage of ultra-high ionic conductivity, suppress the reaction between the kernel and water, carbon dioxide, etc., and prevent the formation of a surface impurity layer on the kernel.

[0041] For example, the mass fraction of the carbon material in the lithium additive may be 0.01%, 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.3%, 0.4%, 0.5%, or 0.5%.

[0042] When the mass fraction of the carbon material in the lithium replenisher is within the range described above, the carbon material in the coating layer effectively improves the conductivity of the coating layer and further improves the electronic conductivity of the surface of the lithium replenisher, thereby improving the transport paths of lithium ions and electrons in the lithium replenisher, while having only a small effect on the lithium replenishment capacity of the lithium replenisher.

[0043] In some embodiments, the lattice constant of the kernel satisfies a=b and a≠c, with c / a being 2-3. This allows for a faster lithium ion transition rate of the lithium replenisher.

[0044] For example, c / a may be 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, or 3.

[0045] If the kernel's cell parameters satisfy a=b and a≠c, the kernel is hexagonal. Due to the characteristic symmetry of the hexagonal system, the basis vectors corresponding to the hexagonal cell are characterized by two sub-axes both being perpendicular to the principal axis, the magnitudes of the basis vectors of the two sub-axes being equal, and the included angle between the sub-axes being 120°. In other words, its cell parameters are a=b≠c, α=β=90°, and γ=120°. In this case, the cell has a layered structure, and by designing a combination of elements with different valences and a non-equilibrium charge in the transition metal layer, it is possible to contribute to the formation of vacancies in the lithium ion layer, enabling rapid transport and highly efficient utilization of lithium ions.

[0046] In some embodiments, a is 0.4 nm to 0.7 nm and c is 1.4 nm to 1.6 nm. This allows for an even faster lithium ion transition rate of the lithium replenisher.

[0047] For example, a may be 0.4nm, 0.45nm, 0.5nm, 0.55nm, 0.6nm, 0.65nm, or 0.7nm.

[0048] For example, c may be 1.4nm, 1.45nm, 1.5nm, 1.55nm, or 1.6nm.

[0049] In this application, "lattice parameters" have the meaning known in the art and may be measured by instruments and methods known in the art. For example, lattice parameters may be obtained by X-ray diffraction testing.

[0050] In some embodiments, the Dv50 particle size of the kernel is 1 μm to 10 μm, and / or the thickness of the coating layer is 50 nm to 500 nm. As a result, the coating layer can improve the storage performance of the lithium replenisher, improve the conductivity of the lithium replenisher, and contribute to the full performance of the lithium replenishment function by the lithium replenisher.

[0051] For example, the Dv50 particle size of the kernel may be 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm, 8 μm, 8.5 μm, 9 μm, 9.5 μm, or 10 μm.

[0052] For example, the thickness of the coating layer may be 50 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, or 500 nm.

[0053] In some examples, the kernel is Li8Zr 0.9 W 0.1 O6, Li7Nb 0.8 Ta 0.2 O6, Li7Sb 0.9 Ta 0.1 O6, Li7Ru 0.7 W 0.2 Ce 0.1O6, Li8Sn 0.9 Ca 0.1 O6, Li8Hf 0.7 W 0.2 Ca 0.1 O6, Li8Ir 0.6 W 0.2 Ce 0.2 O6, Li8Pr 0.5 W 0.3 Ca 0.2 O6, Li8Pt 0.7 W 0.2 Ca 0.1 It contains at least one of the O6 species. This effectively improves the lithium supply capacity of the lithium supplement and lowers the decomposition potential of the lithium supplement.

[0054] When the kernel of a lithium replenisher contains the aforementioned substances, the kernel has a high lithium replenishment capacity and a high lithium replenisher capacity.

[0055] For example, Li8Zr 0.9 W 0.1 The theoretical capacity of O6 is 883 mAh / g, and Li7Nb 0.8 Ta 0.2 The theoretical capacity of O6 is 790mAh / g, and Li7Sb 0.9 Ta 0.1 The theoretical capacity of O6 is 704 mAh / g, and Li7Ru 0.7 W 0.2 Ce 0.1 The theoretical capacity of O6 is 764 mAh / g, compared to Li8Sn 0.9 Ca 0.1 The theoretical capacity of O6 is 793 mAh / g, compared to Li8Hf 0.7 W 0.2 Ca 0.1 The theoretical capacity of O6 is 650 mAh / g, and Li8Ir 0.6 W 0.2 Ce 0.2 The theoretical capacity of O6 is 624 mAh / g, and Li8Pr 0.5 W 0.3 Ca 0.2 The theoretical capacity of O6 is 783 mAh / g, compared to Li8Pt. 0.7 W 0.2 Ca 0.1 The theoretical capacity of O6 is 619 mAh / g.

[0056] In some examples, the degree of graphitization of the carbon material is 60% or higher. This further improves the conductivity of the lithium replenisher.

[0057] When the degree of graphitization of a carbon material is within the range described above, the closer the internal structure of the carbon material is to ideal graphite, the better its conductivity.

[0058] In a second aspect of this application, the present application proposes a method for manufacturing the lithium replenisher described above. This makes it possible to manufacture a lithium replenisher with excellent lithium replenishment performance as described above in a simple manner. Specifically, the method for manufacturing the lithium replenisher may include the following steps.

[0059] In Step S100, the lithium source, M1 source, and M2 source are subjected to a first sintering treatment in an oxygen-containing atmosphere.

[0060] In some embodiments, in this step, the M1 source, the M2 source, and the lithium source are uniformly mixed in the ratio of the amounts of the substances in the chemical formula, and a sintering process is carried out in an oxygen-containing atmosphere, thereby creating a Li x M1 y M2 1-y Obtain a kernel for lithium replenisher that is O6, where 6 ≤ x ≤ 8 and 0 <y<1である。

[0061] In some embodiments, the lithium source includes at least one of lithium carbonate, lithium hydroxide, and lithium oxide.

[0062] In some embodiments, the M1 source includes at least one of the oxides of M1, the chlorides of M1, the nitrates of M1, and the hydroxides of M1.

[0063] In some embodiments, the M2 source includes at least one of M2 oxides, M2 chlorides, M2 nitrates, and M2 hydroxides.

[0064] In some embodiments, the temperature of the first sintering treatment is 700°C to 1200°C, and the duration of the first sintering treatment is 8 hours to 24 hours. This contributes to obtaining pure phase kernel particles with appropriate particle sizes.

[0065] For example, the temperature of the first sintering process may be 700°C, 800°C, 900°C, 1000°C, 1100°C, or 1200°C.

[0066] For example, the duration of the first sintering treatment may be 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h, or 24h.

[0067] When the temperature and time of the first sintering treatment are within the range described above, it is advantageous for the formation of a hexagonal crystal kernel, the stability of the material phase structure is relatively high, there are few impurities, and the particle size of the formed kernel is appropriate.

[0068] In some embodiments, the oxygen-containing atmosphere may be an oxygen-containing atmosphere such as oxygen gas or air.

[0069] In step S200, the kernel, M source, and carbon source are subjected to a second sintering treatment in an inert atmosphere.

[0070] In some embodiments, in this step, the M source and the kernel are uniformly mixed, then further mixed with a carbon source, and then sintered in an inert atmosphere to form a coating layer on at least a portion of the surface of the kernel to obtain the lithium replenisher.

[0071] In some embodiments, the M source includes at least one of zirconium propoxide, zirconium oxide, zirconium nitrate, zirconium oxychloride, lithium zirconate, zirconium chloride, titanium oxide, titanium tetrachloride, titanium nitrate, and titanium alkoxide.

[0072] In some embodiments, the carbon source includes at least one of glucose, starch, sucrose, and graphite, thereby contributing to the formation of lithium-containing metal oxides on the surface of the kernel.

[0073] In some embodiments, the temperature of the second sintering treatment is 400°C to 800°C, and the duration of the second sintering treatment is 6H to 10H. This contributes to the formation of lithium-containing metal oxides and carbon materials in the coating layer.

[0074] For example, the temperature of the second sintering process may be 400°C, 500°C, 600°C, 700°C, or 800°C.

[0075] For example, the duration of the second sintering process may be 6h, 7h, 8h, 9h, or 10h.

[0076] When the temperature and time of the second sintering process are within the range described above, it contributes to the formation of tetragonal lithium-containing metal oxides and carbon materials with a high degree of graphitization, resulting in high stability of the material phase structure and minimal carbon loss.

[0077] In some embodiments, an inert atmosphere is required in the second sintering process for forming the coating layer, thereby effectively reducing the reaction between the carbon source and the active atmosphere and mitigating carbon leaching. For example, in an active atmosphere such as an oxygen-containing atmosphere, the carbon source is oxidized and released as carbon dioxide or carbon monoxide gas, resulting in carbon leaching.

[0078] For example, the inert atmosphere may include non-oxygen-containing and non-hydrogen-containing atmospheres such as nitrogen and argon.

[0079] In some embodiments, the process further includes a step of mixing the kernel, the M source, and the carbon source in a solvent and drying them before the second sintering process. This allows the kernel, carbon source, and M source to be sufficiently dispersed in the solvent, contributing to a more uniform mixing of the kernel, M source, and carbon source, and also contributes to improving the uniformity of the coating by removing the solvent by the drying process.

[0080] In some examples, the solvent includes at least one of ethanol and isopropanol.

[0081] In some embodiments, the drying process includes at least one of spray drying, freeze-drying, and flash drying.

[0082] In a third aspect of this application, the present application proposes a positive electrode slurry comprising the lithium replenisher described above, or a lithium replenisher manufactured by the method described above. The positive electrode slurry thereby possesses all the constituent elements and advantages of the lithium replenisher and the method for manufacturing the lithium replenisher described above. Further explanation is omitted here.

[0083] In some embodiments, the viscosity of the positive electrode slurry is between 1000 mPa·s and 8000 mPa·s. This contributes to improving the processing performance of the positive electrode slurry.

[0084] By forming a coating layer on the surface of the lithium replenisher kernel, the influence of the kernel's alkaline surface on the slurry stability is effectively suppressed. After adding the lithium replenisher to the cathode slurry, lithium deposition reactions caused by the strongly alkaline surface of the lithium replenisher are eliminated. This effectively mitigates the significant increase in viscosity of the cathode slurry due to the increased alkalinity of the cathode slurry, contributing to the satisfaction of the cathode slurry coating requirements.

[0085] For example, a positive electrode slurry may be obtained by mixing a positive electrode material, a lithium replenisher, a solvent (e.g., N-methylpyrrolidone), an adhesive (e.g., polyvinylidene fluoride), and a conductive agent (e.g., carbon black, acetylene black) in a mass ratio of 90:2:100:4:4.

[0086] In a fourth aspect of the present application, the present application proposes a battery comprising a positive electrode tab including a positive electrode current collector and a positive electrode active material layer located on at least one side of the positive electrode current collector, wherein the positive electrode active material layer is manufactured from the positive electrode slurry described above. The battery thus possesses all the constituent requirements and advantages of the positive electrode slurry described above. Further explanation is omitted here.

[0087] The following describes the technical proposal of this application with specific examples. These examples are for illustrative purposes only and do not limit the scope of this application. Unless otherwise specified in the examples, specific techniques or conditions shall be followed in accordance with the techniques or conditions described in the literature in this industry or in accordance with the product manual. Unless otherwise specified, the reagents or equipment used shall be general-purpose products available on the market.

[0088] Example 1 (1) Lithium carbonate (lithium source), zirconium dioxide (M1 source), and tungsten oxide (M2 source) are uniformly mixed in a high mixer in a molar ratio of Li:Zr:W = 8:0:9:0:1, and sintered at 900°C for 10 hours in an air atmosphere to form a compound with the chemical formula Li8Zr 0.9 W 0.1 Obtain the O6 kernel.

[0089] (2) Zirconium propoxide (M source) and the kernel are weighed in a molar ratio of Zr:W = 1:10 and mixed to obtain the first mixture. The first mixture and glucose (carbon source) are weighed in a mass ratio of 99:1 and mixed to obtain the second mixture. The second mixture is added to pure water at 50% of its intrinsic content to obtain a mixed material. The mixed material is sand-milled at a rotation speed of 2500 rpm for 1 hour, and the resulting mixed slurry is dried in a spray dryer to obtain a powder. The powder is sintered at 800°C under a nitrogen atmosphere, and finally the coating layer contains Li2ZrO3 and carbon material, and the kernel is Li8Zr 0.9 W 0.1 Obtain a lithium replenisher that is O6.

[0090] Examples 2-16 and Comparative Examples 1-16 are almost identical to Example 1, but the differences are shown in Table 1. In Comparative Example 3, no M2 source was added when forming the kernel; in Reference 4, no M1 source was added when forming the kernel; in Comparative Example 5, no M source was added when forming the coating layer; and in Comparative Example 6, no carbon source was added when forming the coating layer. Table 1 [Table 1-1] [Table 1-2] Table 2 shows the parameters of the lithium replenisher in the above-described examples and comparative examples. Table 2 [Table 2]

[0091] The lithium replenisher used in the above-described examples and comparative examples was manufactured as a coin-type battery, and the manufacturing method is as follows.

[0092] The lithium replenishment material, acetylene black (a conductive agent), and polyvinylidene fluoride (an adhesive) are mixed in a mass ratio of 90:5:5. This mixture is applied to aluminum foil, dried, and then press-molded at a pressure of 100 MPa to form an electrode tab with a diameter of 12 mm and a thickness of 120 μm to form the positive electrode tab. A lithium metal tab with a diameter of 17 mm and a thickness of 1 mm is used as the negative electrode tab. A Celgard 2400 porous membrane with a thickness of 25 μm is used as the separator. 1 mol / L LiPF6 is used as the electrolyte, and an equivolute mixture of ethylene carbonate (EC) and diethyl carbonate (DEC) is used as the solvent. The positive electrode tab, separator, negative electrode tab, and electrolyte are assembled into a 2025 type coin cell in an Ar gas glove box with water and oxygen content of less than 5 ppm.

[0093] The coin-type batteries in the above-described examples and comparative examples were subjected to the following tests, and the results of these tests are shown in Table 2.

[0094] Regarding the decomposition potential and charge / discharge capacity, rate tests were performed on assembled coin-type batteries under conditions of 3.0V to 4.9V and 0.1C. The charge ratio capacity, discharge ratio capacity, and discharge ratio energy were read from the test software, where the lithium replenisher decomposition potential = discharge ratio energy / discharge ratio capacity.

[0095] Regarding the lithium-ion transition rate of lithium replenisher, assembled coin-type batteries are subjected to EIS AC impedance testing on an electrochemical workstation, and the lithium-ion transition rate of the lithium replenisher is obtained from the slope of the linear segment in the AC impedance diagram. Table 3 [Table 3]

[0096] As can be seen from the test results, the coating layer on the surface of the lithium replenisher in Examples 1 to 16 effectively reduced the increase in viscosity of the positive electrode slurry caused by the alkalinity of the kernel surface during the use of the lithium replenisher, resulting in excellent processing performance of the positive electrode slurry. The high initial charge capacity of the lithium replenisher indicates sufficient lithium ion release from the lithium replenisher during the charging process, while the low initial discharge capacity of the lithium replenisher indicates that fewer lithium ions are reinserted into the lithium replenisher during the discharge process, thus achieving a good home position pre-lithification effect for lithium batteries.

[0097] Figure 1 is a scanning electron microscope image of the lithium replenisher in Example 1. From this figure, it can be seen that there is a coating layer on the surface of the kernel. Figure 2 shows that the S1 / S2 of the lithium replenisher in Example 1 is 0.03, and the S1 / S2 of the lithium replenisher in Comparative Example 5 is 0. Figure 3 is a charge / discharge graph of the coin cell battery in Example 1.

[0098] In Comparative Example 1, the viscosity of the positive electrode slurry increased significantly because there was too little tetragonal lithium-containing metal oxide in the coating layer of the lithium replenisher. In Comparative Example 2, the viscosity of the positive electrode slurry increased significantly because there was too little tetragonal lithium-containing metal oxide in the lithium replenisher. Because there was a large amount of tetragonal lithium-containing metal oxide, the viscosity of the positive electrode slurry decreased, but at the same time, the lithium replenishment capacity of the lithium replenisher also decreased significantly. In Comparative Example 3, the kernel of the lithium replenisher did not contain the M2 element, so the transport rate of lithium ions in the kernel decreased, and since the kernel of the lithium replenisher in Comparative Example 3 did not contain the M1 element, the lithium replenishment capacity of the lithium replenisher was too small. In Comparative Example 5, the viscosity of the positive electrode slurry increased significantly because no tetragonal lithium-containing metal oxide was formed in the coating layer of the lithium replenisher. In Comparative Example 6, since no carbon material was formed in the coating layer of the lithium replenisher, the lithium replenishment capacity of the lithium replenisher was poorly exhibited.

[0099] In the description of this application, the terms "first" and "second" are merely descriptive and should not be understood as indicating or implying relative importance, or implicitly indicating the number of constituent elements being referred to. The limitations of "first constituent element" and "second constituent element" are used to mean that they may include one or more such constituent elements.

[0100] In the description of this application, "A and / or B" may include A alone, B alone, or either A or B, where A and B are merely examples and may be any constituent elements connected by "and / or" in this application.

[0101] Furthermore, this application is not limited to the embodiments described above. The embodiments described above are merely illustrative. Within the scope of the technical proposal of this application, any embodiment that has substantially the same configuration as the technical concept and produces similar effects is considered to be covered by the technical scope of this application. In addition, as long as it does not depart from the spirit of this application, various modifications of the embodiments that a person skilled in the art could conceive, and other forms constructed by combining some of the components of the embodiments, are all included within the scope of this application.

Claims

1. Chemical formula Li ｘ M1 ｙ M2 １－ｙ O ６ A kernel that satisfies the following conditions, where 6 ≤ x ≤ 8 and 0 < y < 1, where M1 is at least one of Zr, Nb, Sb, Bi, Ru, Ta, Sn, Hf, Ir, Pr, Pt, Np, and M2 is at least one of W, Ge, Ca, Ce, K, Ta, and At least, a coating layer located on a portion of the surface of the kernel, comprising a lithium-containing metal oxide and a carbon material, wherein the lithium-containing metal oxide has the chemical formula Li ａ M ｂ O ｃ The following conditions are met, where 1.8 ≤ a ≤ 2, 0.7 ≤ b ≤ 1.1, and 2.8 ≤ c ≤ 3, and M includes a coating layer containing Ti and / or Zr, When the 2θ diffraction angle is within the range of 20.1° to 20.3°, the peak intensity of the diffraction peak for X-rays is S1. A lithium replenisher in which the peak intensity of the diffraction peak for X-rays is S2 when the 2θ diffraction angle is in the range of 17° to 17.3°, and S1 / S2 is 0.02 to 0.

05.

2. The lithium replenisher according to claim 1, wherein the mass fraction of the lithium-containing metal oxide in the lithium replenisher is 0.01% to 0.1%, and / or the mass fraction of the carbon material in the lithium replenisher is 0.01% to 0.5%.

3. The lithium replenisher according to claim 1, wherein the lattice constant of the kernel satisfies a = b, a ≠ c, and c / a is 2 to 3.

4. The lithium replenisher according to claim 3, wherein a is 0.4 nm to 0.7 nm and c is 1.4 nm to 1.6 nm.

5. The lithium replenisher according to any one of claims 1 to 4, wherein the Dv50 particle size of the kernel is 1 μm to 10 μm, and / or the thickness of the coating layer is 50 nm to 500 nm.

6. The kernel is Li ８ Zr ０．９ W ０．１ O ６ 、Li ７ Nb ０．８ Ta ０．２ O ６ 、Li ７ Sb ０．９ Ta ０．１ O ６ 、Li ７ Ru ０．７ W ０．２ Ce ０．１ O ６ 、Li ８ Sn ０．９ Ca ０．１ O ６ 、Li ８ Hf ０．７ W ０．２ Ca ０．１ O ６ 、Li ８ Ir ０．６ W ０．２ Ce ０．２ O ６ 、Li ８ Pr ０．５ W ０．３ Ca ０．２ O ６ 、Li ８ Pt ０．７ W ０．２ Ca ０．１ O ６ The lithium supplement according to any one of claims 1 to 4, comprising at least one of the above.

7. The lithium replenisher according to any one of claims 1 to 4, wherein the degree of graphitization of the carbon material is 60% or more.

8. A method for producing a lithium replenisher according to any one of claims 1 to 7, The process involves a step of obtaining a kernel by performing a first sintering treatment on a lithium source, an M1 source, and an M2 source in an oxygen-containing atmosphere, A method comprising the step of performing a second sintering treatment on the kernel, M source, and carbon source in an inert atmosphere to form a coating layer on at least a portion of the surface of the kernel to obtain the lithium replenisher.

9. The lithium source comprises and / or at least one of lithium carbonate, lithium hydroxide, and lithium oxide. The M1 source comprises at least one of the oxides of M1, the chlorides of M1, the nitrates of M1, and the hydroxides of M1, and / or The method according to claim 8, wherein the M2 source includes at least one of M2 oxide, M2 chloride, M2 nitrate, and M2 hydroxide.

10. The method according to claim 9, wherein the temperature of the first sintering treatment is 700°C to 1200°C, and the duration of the first sintering treatment is 8 hours to 24 hours.

11. The M source comprises at least one of zirconium propoxide, zirconium oxide, zirconium nitrate, zirconium oxychloride, lithium zirconate, zirconium chloride, titanium oxide, titanium tetrachloride, titanium nitrate, and titanium alkoxide, and / or The method according to any one of claims 8 to 10, wherein the carbon source comprises at least one of glucose, starch, sucrose, and graphite.

12. The method according to claim 11, wherein the temperature of the second sintering treatment is 400°C to 800°C, and the duration of the second sintering treatment is 6 hours to 10 hours.

13. The method according to claim 8, further comprising the step of mixing the kernel, the M source, and the carbon source in a solvent and performing a drying treatment before the second sintering treatment.

14. The solvent comprises at least one of ethanol and isopropanol, and / or The method according to claim 13, wherein the drying treatment includes at least one of spray drying, freeze-drying, and flash drying.

15. A positive electrode slurry comprising a lithium replenisher according to any one of claims 1 to 7, or a lithium replenisher manufactured by the method according to any one of claims 8 to 14.

16. The positive electrode slurry according to claim 15, wherein the viscosity of the positive electrode slurry is 1000 mPa·s to 8000 mPa·s.

17. A positive electrode tab includes a positive electrode current collector and a positive electrode active material layer located on at least one side of the positive electrode current collector, A battery wherein the positive electrode active material layer is manufactured by the positive electrode slurry described in claim 15 or 16.

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