Lithium-sodium composite cathode material, its preparation method and lithium-ion battery

Abstract

The present invention relates to the technical field of lithium-ion batteries, and particularly to a lithium-sodium composite cathode material, a preparation method thereof, and a lithium-ion battery. The preparation method of the lithium-sodium composite cathode material comprises the following steps: (a) respectively subjecting a nickel source, a cobalt source, and a manganese source to ball milling treatment to obtain a nickel source coarse powder, a cobalt source coarse powder, and a manganese source coarse powder, dispersing the nickel source coarse powder, the cobalt source coarse powder, and the manganese source coarse powder in a solvent respectively, and then respectively performing spray granulation to obtain a nickel source fine powder, a cobalt source fine powder, and a manganese source fine powder; (b) mixing the nickel source fine powder, the cobalt source fine powder, and the manganese source fine powder with a lithium source and a sodium source, and then performing calcination treatment. The present invention does not need to prepare a precursor, directly mixes the fine powders of the nickel source, the cobalt source, and the manganese source with the lithium source and the sodium source and then performs calcination, and a lithium-sodium composite cathode material can be obtained, which simplifies the preparation process, reduces the production cost, and also improves the stability of the material.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium-ion batteries, and particularly to a lithium-sodium composite cathode material, a preparation method thereof, and a lithium-ion battery. Background Art

[0002] With the development of technology, the energy structure of human society is constantly adjusting and changing. Traditional fossil fuels represented by oil and coal are being replaced by emerging green energy sources represented by wind energy and solar energy, and the corresponding energy storage devices are also constantly developing and updating. Lithium-ion batteries are outstanding among new energy storage devices, with the advantages of high energy density, long cycle life, and high safety. The existing lithium-ion battery chemical system mainly consists of four parts: a cathode, an anode, a separator, and an electrolyte. Among them, the cathode material, as the provider of lithium ions, directly affects the electrical performance and safety performance during battery operation. Therefore, it is crucial to develop a suitable cathode material.

[0003] Currently, the commercially available cathode materials are mainly divided into two categories: lithium nickel cobalt manganese oxide and lithium iron phosphate. A large amount of lithium element is consumed during the preparation of these two materials. However, the abundance of lithium element in the earth's crust is only 0.0065%. To avoid the shortage and high price of lithium resources restricting its development, it is necessary to develop new low-lithium or even lithium-free cathode materials.

[0004] The existing new cathode materials are mainly represented by sodium-containing systems, which are divided into layered oxides, polyanion compounds, and Prussian blue analogs. However, in the existing sodium battery materials, since the radius of sodium ions is larger than that of lithium ions, compared with lithium battery cathode materials, the volume change during the cycling process of sodium battery materials is more significant, and the cycle life is shorter; at the same time, the diffusion rate of sodium ions is slow, which limits the performance of the battery power. Therefore, it is difficult to achieve large-scale commercial applications of pure sodium battery cathode materials in the short term. The lithium-sodium composite cathode material retains the advantages of long cycle life and high energy density of lithium batteries, while taking into account the low-cost advantage of sodium batteries. Most of the existing synthesis strategies for lithium-sodium composite cathode materials are based on the traditional high-temperature solid-state method, that is, first prepare the precursor by the co-precipitation method, then mix it with the sodium source and calcine it at high temperature to obtain the sodium battery intermediate, and finally mix it with the lithium source and calcine it at high temperature to obtain the lithium-sodium composite cathode material. For example, the patent application with the publication number CN116314746A records a preparation method of a lithium-sodium composite ternary material. First, prepare the sodium-ion ternary cathode material, and then mix and sinter the sodium-ion ternary cathode material, the lithium source, and the ternary precursor again to prepare the lithium-sodium composite ternary cathode material. This process not only requires the preparation of the precursor but also involves multiple sintering processes, which greatly increases the production cost and affects the market competitiveness of the lithium-sodium composite cathode material.

[0005] In view of this, the present invention is specifically proposed. Summary of the Invention

[0006] One object of the present invention is to provide a method for preparing a lithium-sodium composite cathode material to solve the technical problems of complicated preparation process and high production cost existing in the prior art.

[0007] Another object of the present invention is to provide a lithium-sodium composite cathode material with excellent specific capacity and cycling performance, etc.

[0008] Still another object of the present invention is to provide a lithium-ion battery including the above-mentioned lithium-sodium composite cathode material.

[0009] To achieve the above objects of the present invention, on the one hand, the present invention provides a method for preparing a lithium-sodium composite cathode material, including the following steps:

[0010] (a) Respectively ball-mill a nickel source, a cobalt source and a manganese source to obtain a nickel source coarse powder, a cobalt source coarse powder and a manganese source coarse powder, disperse the nickel source coarse powder, the cobalt source coarse powder and the manganese source coarse powder in a solvent respectively, and then perform spray granulation respectively to obtain a nickel source fine powder, a cobalt source fine powder and a manganese source fine powder;

[0011] (b) After mixing the nickel source fine powder, the cobalt source fine powder and the manganese source fine powder with a lithium source and a sodium source, perform a calcination treatment.

[0012] In a specific embodiment of the present invention, the D50 particle size of the nickel source coarse powder, the cobalt source coarse powder and the manganese source coarse powder is independently selected from 3 to 10 μm.

[0013] In a specific embodiment of the present invention, the D50 particle size of the nickel source fine powder, the cobalt source fine powder and the manganese source fine powder is independently selected from 0.5 to 2 μm.

[0014] In a specific embodiment of the present invention, the rotation speed of the ball-milling treatment is 40 to 80 r / min, and the time of the ball-milling treatment is 0.5 to 2 h.

[0015] In a specific embodiment of the present invention, the solvent includes at least one of water and ethanol. Further, the dispersion concentration of the nickel source coarse powder, the cobalt source coarse powder and the manganese source coarse powder in the solvent is independently selected from 30% to 35%.

[0016] In a specific embodiment of the present invention, the conditions of the spray granulation include: the feeding rate is 3 to 5 m 3 / min, the inlet air temperature is 100 to 120 °C, the outlet air temperature is 40 to 60 °C, and the pressure is 1.3 to 1.5 Mpa.

[0017] In a specific embodiment of the present invention, the nickel source is nickel oxide or nickel carbonate, the cobalt source is cobalt oxide or cobalt carbonate, and the manganese source is manganese oxide or manganese carbonate.

[0018] In a specific embodiment of the present invention, the lithium source is at least one of lithium carbonate, lithium hydroxide, and lithium chloride; the sodium source is at least one of sodium carbonate, sodium hydroxide, and sodium chloride.

[0019] In a specific embodiment of the present invention, the temperature of the calcination treatment is 860 - 920 °C, and the time of the calcination treatment is 8 - 16 h. Further, the atmosphere of the calcination treatment is an oxygen atmosphere.

[0020] In a specific embodiment of the present invention, the chemical formula of the lithium-sodium composite cathode material is Na x Li 1-x (Ni y Co z Mn 1-y-z )O2, where 0 < x < 0.2, 0 < y < 0.9, and 0 < z ≤ 0.1.

[0021] On the other hand, the present invention provides a lithium-sodium composite cathode material prepared by the preparation method of any one of the above-mentioned lithium-sodium composite cathode materials.

[0022] On another aspect, the present invention provides a lithium-ion battery, including any one of the above-mentioned lithium-sodium composite cathode materials.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] (1) In the preparation method of the lithium-sodium composite cathode material of the present invention, there is no need to prepare a precursor. The fine powders of the nickel source, cobalt source, and manganese source are directly mixed with the lithium source and the sodium source and then calcined to obtain the lithium-sodium composite cathode material, which simplifies the preparation process, reduces the production cost, and improves the stability of the material at the same time;

[0025] (2) The lithium-sodium composite cathode material prepared by the method of the present invention has a specific capacity per gram and cycling performance comparable to or even better than those of traditional pure lithium ternary materials. Specific Embodiments

[0026] The technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments. However, those skilled in the art will understand that the following described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments, and are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present invention. For those conditions not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. For reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0027] On the one hand, the present invention provides a method for preparing a lithium-sodium composite cathode material, comprising the following steps:

[0028] (a) Respectively ball-mill a nickel source, a cobalt source, and a manganese source to obtain a nickel source coarse powder, a cobalt source coarse powder, and a manganese source coarse powder. Disperse the nickel source coarse powder, the cobalt source coarse powder, and the manganese source coarse powder in a solvent respectively, and then perform spray granulation respectively to obtain a nickel source fine powder, a cobalt source fine powder, and a manganese source fine powder;

[0029] (b) After mixing the nickel source fine powder, the cobalt source fine powder, and the manganese source fine powder with a lithium source and a sodium source, perform a calcination treatment.

[0030] The present invention uses ball milling to preliminarily pulverize a nickel source, a cobalt source, and a manganese source to obtain coarse powders, which is convenient for spray granulation. The particle size of the fine powder obtained after spray granulation is greatly reduced. After directly mixing the fine powder with a lithium source and a sodium source, during the high-temperature calcination process, the lithium source and the sodium source melt and migrate into the interior of the fine powder particles. And because the fine powder raw material has a small particle size, the uniformity and reaction rate of the reaction are greatly improved, taking into account ensuring the uniformity and stability of the product.

[0031] The preparation method of the present invention abandons the existing processes of preparing a precursor by a co-precipitation method and multi-step sintering. There is no need to prepare a precursor, which reduces the material production cost. At the same time, the stability and electrochemical performance of the obtained lithium-sodium composite cathode material are ensured, making the lithium-sodium composite cathode material have a broader application prospect.

[0032] Due to the differences in the initial particle sizes of the nickel source, the cobalt source, and the manganese source, if the nickel source, the cobalt source, and the manganese source are ball-milled and spray-dried together, the particle size distribution of the obtained material is uneven. Then, after performing a calcination treatment with a lithium source and a sodium source, the uniformity of the obtained product is not good. The present invention respectively ball-mills the nickel source, the cobalt source, and the manganese source, then performs spray granulation to obtain corresponding fine powders, and then performs a calcination treatment with a lithium source and a sodium source, which can significantly improve the uniformity of the reaction process and the uniformity of the obtained product, and improve the stability and electrochemical performance of the cathode material.

[0033] In a specific embodiment of the present invention, the D50 particle sizes of the nickel source coarse powder, the cobalt source coarse powder, and the manganese source coarse powder are each independently selected from 3 to 10 μm.

[0034] In different embodiments, the D50 particle sizes of the nickel source coarse powder, the cobalt source coarse powder, and the manganese source coarse powder obtained by ball milling can be each independently selected from but not limited to 3 μm, 5 μm, 7 μm, 9 μm, 10 μm or the range composed of any two of them. By controlling the D50 particle size of the coarse powder to meet the above range through ball milling, it is more beneficial to reduce the material particle size to the corresponding fine powder state during the subsequent spray granulation process, and further improve the uniformity of the reaction with the sodium source and the lithium source during the subsequent calcination process.

[0035] In a specific embodiment of the present invention, the D50 particle size of the nickel source fine powder, cobalt source fine powder, and manganese source fine powder is independently selected from 0.5 to 2 μm.

[0036] In different embodiments, for example, the D50 particle size of the nickel source fine powder, cobalt source fine powder, and manganese source fine powder obtained by spray granulation can be independently selected from but not limited to 0.5 μm, 0.8 μm, 1.2 μm, 1.5 μm, 2 μm, or a range composed of any two of them. When using the nickel source fine powder, cobalt source fine powder, and manganese source fine powder within the above particle size range for calcination with the lithium source and sodium source, the reaction uniformity and reaction rate can be further improved. If the particle size of the fine powder is too large, the particles are not fully developed during the calcination process, resulting in poor uniformity of the final product; if the particle size of the fine powder is too small, the particles will seriously agglomerate during the calcination process and are difficult to develop, and the performance of the final product is poor.

[0037] In actual operation, the D50 particle size of the nickel source fine powder, cobalt source fine powder, and manganese source fine powder can be the same or different, as long as the D50 particle size of the nickel source fine powder, cobalt source fine powder, and manganese source fine powder is within the above range. In some preferred embodiments, the D50 particle sizes of the nickel source fine powder, cobalt source fine powder, and manganese source fine powder are close, such as the same or the D50 particle size fluctuation range is within 0% - 10% (the fluctuation refers to the ratio of the absolute value of the difference in D50 particle size to the D50 particle size).

[0038] In a specific embodiment of the present invention, the rotation speed of the ball milling treatment is 40 - 80 r / min, and the time of the ball milling treatment is 0.5 - 2 h.

[0039] In different embodiments, for example, the rotation speed of the ball milling treatment can be selected from but not limited to 40 r / min, 50 r / min, 60 r / min, 70 r / min, 80 r / min, or a range composed of any two of them, and the time of the ball milling treatment can be selected from but not limited to 0.5 h, 0.8 h, 1 h, 1.2 h, 1.5 h, 1.8 h, 2 h, or a range composed of any two of them.

[0040] In actual operation, the ball milling treatment can be carried out using a conventional high-energy ball mill. The conditions of the ball milling treatment can be adjusted according to the particle size of the coarse powder actually obtained to obtain a coarse powder that meets the particle size requirements.

[0041] In a specific embodiment of the present invention, the solvent includes at least one of water and ethanol. Further, the dispersion concentration of the nickel source coarse powder, cobalt source coarse powder, and manganese source coarse powder in the solvent is independently selected from 30% - 35%.

[0042] The coarse nickel source powder is dispersed in a solvent to obtain a suspension of the coarse nickel source powder; the coarse cobalt source powder is dispersed in a solvent to obtain a suspension of the coarse cobalt source powder; the coarse manganese source powder is dispersed in a solvent to obtain a suspension of the coarse manganese source powder. It should be noted that the dispersion concentration here refers to the mass fraction of the coarse nickel source powder, the coarse cobalt source powder, or the coarse manganese source powder in their respective suspensions.

[0043] In different embodiments, the dispersion concentrations of the coarse nickel source powder, the coarse cobalt source powder, and the coarse manganese source powder in the solvent can be independently selected from but not limited to 30%, 30.5%, 31%, 31.5%, 32%, 32.5%, 33%, 33.5%, 34%, 34.5%, 35%, or the range composed of any two of them.

[0044] In a specific embodiment of the present invention, the conditions for spray granulation include: the feeding rate is 3 - 5 m 3 / min, the inlet air temperature is 100 - 120 °C, the outlet air temperature is 40 - 60 °C, and the pressure is 1.3 - 1.5 Mpa.

[0045] In different embodiments, among the conditions for spray granulation, the feeding rate can be selected from but not limited to 3 m 3 / min, 4 m 3 / min, 5 m 3 / min, or the range composed of any two of them; the inlet air temperature can be selected from but not limited to 100 °C, 110 °C, 120 °C, or the range composed of any two of them; the outlet air temperature can be selected from but not limited to 40 °C, 50 °C, 60 °C, or the range composed of any two of them; the pressure can be selected from but not limited to 1.3 Mpa, 1.4 Mpa, 1.5 Mpa, or the range composed of any two of them.

[0046] In a specific embodiment of the present invention, the nickel source is nickel oxide or nickel carbonate, the cobalt source is cobalt oxide or cobalt carbonate, and the manganese source is manganese oxide or manganese carbonate.

[0047] In a specific embodiment of the present invention, the lithium source is at least one of lithium carbonate, lithium hydroxide, and lithium chloride; the sodium source is at least one of sodium carbonate, sodium hydroxide, and sodium chloride.

[0048] In actual operation, the mixing of each fine powder with the lithium source and the sodium source is carried out in a high-speed mixer. The fine nickel source powder, the fine zirconium source powder, and the fine manganese source powder can be premixed evenly in the high-speed mixer and then continuously mixed evenly with the lithium source and the sodium source. The mixing speed of the high-speed mixer can be adjusted according to the actual situation to ensure that the materials are mixed evenly, for example, the speed is 1000 - 1440 rpm, the premixing time is 10 - 30 min, and the time for continuously mixing with the lithium source and the sodium source is 30 - 60 min.

[0049] In a specific embodiment of the present invention, the calcination temperature is 860 - 920 °C, and the calcination time is 8 - 16 h. Further, the atmosphere for the calcination treatment is an oxygen atmosphere.

[0050] In different embodiments, the calcination temperature can be selected from but not limited to 860 °C, 970 °C, 880 °C, 890 °C, 900 °C, 910 °C, 920 °C, or a range composed of any two of them, and the calcination time can be selected from but not limited to 8 h, 9 h, 10 h, 11 h, 12 h, 13 h, 14 h, 15 h, 16 h, or a range composed of any two of them.

[0051] In the present invention, after ball milling and spray granulation treatment of the nickel source, cobalt source, and manganese source, with certain calcination conditions, the corresponding lithium-sodium composite cathode material can be obtained through one calcination. If the calcination temperature is too high, the particle growth will be too large and the capacity will be difficult to exert; if the calcination temperature is too low, the particle growth will be incomplete, the agglomeration will be serious, and the product uniformity will be poor.

[0052] In a specific embodiment of the present invention, the chemical formula of the lithium-sodium composite cathode material is Na x Li 1-x (Ni y Co z Mn 1-y-z )O2, where 0 < x < 0.2, 0 < y < 0.9, 0 < z ≤ 0.1.

[0053] In actual operation, the nickel source, cobalt source, manganese source, lithium source, and sodium source are weighed according to the stoichiometric ratio. In different embodiments, x can be selected from but not limited to 0.001, 0.005, 0.008, 0.01, 0.02, 0.05, 0.08, 0.1, 0.12, 0.15, 0.18, 0.19, or a range composed of any two of them; y can be selected from but not limited to 0.01, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.85, 0.89, or a range composed of any two of them; z can be selected from but not limited to 0.01, 0.02, 0.05, 0.08, 0.1, or a range composed of any two of them.

[0054] In a specific embodiment of the present invention, it further includes: pulverizing and sieving the calcined material. Through pulverizing and sieving, a material meeting the particle size requirements for battery use is obtained.

[0055] On the other hand, the present invention provides a lithium-sodium composite cathode material prepared by using the preparation method of any one of the above lithium-sodium composite cathode materials.

[0056] The initial discharge specific capacity of the lithium-sodium composite cathode material of the present invention at a 0.1C rate tested by the method of GB / T 37201-2018 can reach 196.9-211.3 mAh / g, and the capacity retention rate after 50 cycles of charge and discharge at a 1C rate tested by the method of GB / T 37207-2018 can reach 91.8%-96.2%. For example, the initial discharge specific capacity at a 0.1C rate can reach 200 mAh / g, 202 mAh / g, 205 mAh / g, 208 mAh / g, 210 mAh / g, etc., and the capacity retention rate after 50 cycles of charge and discharge at a 1C rate can reach 92%, 93%, 94%, 95%, 96%, etc.

[0057] On the other hand, the present invention provides a lithium-ion battery, including any one of the above lithium-sodium composite cathode materials.

[0058] Example 1

[0059] This example provides a lithium-sodium composite cathode material and its preparation method. The lithium-sodium composite cathode material is Li 0.9 Na 0.1 (Ni 0.8 Co 0.1 Mn 0.1 )O2, and the preparation method includes the following steps:

[0060] (1) Weigh 600 g of nickel oxide and place it in a high-energy ball mill. Ball mill it at a speed of 60 rpm for 1 h to obtain nickel oxide coarse powder with a D50 particle size of 5 μm; then place the nickel oxide coarse powder in 1200 mL of water, stir and mix evenly to obtain a suspension of nickel oxide coarse powder; spray granulate the suspension of nickel oxide coarse powder through a spray granulator to obtain nickel oxide fine powder with a D50 particle size of 1 μm. Among them, the conditions for spray granulation include: the feeding rate is 5 m 3 / min, the inlet air temperature is 120 °C, the outlet air temperature is 60 °C, and the pressure is 1.5 Mpa;

[0061] Weigh 166 g of cobalt oxide and place it in a high-energy ball mill. Ball mill it at a speed of 60 rpm for 1.2 h to obtain cobalt oxide coarse powder with a D50 particle size of 5 μm; then place the cobalt oxide coarse powder in 332 mL of water, stir and mix evenly to obtain a suspension of cobalt oxide coarse powder; spray granulate the suspension of cobalt oxide coarse powder through a spray granulator to obtain cobalt oxide fine powder with a D50 particle size of 1 μm. Among them, the conditions for spray granulation include: the feeding rate is 5 m 3 / min, the inlet air temperature is 120 °C, the outlet air temperature is 60 °C, and the pressure is 1.5 Mpa;

[0062] Weigh 87 g of manganese dioxide and place it in a high-energy ball mill. Ball mill it at a speed of 60 rpm for 0.8 h to obtain manganese dioxide coarse powder with a D50 particle size of 5 μm. Then, place the manganese dioxide coarse powder in 174 mL of water and stir to mix evenly to obtain a suspension of the manganese dioxide coarse powder. Spray granulate the suspension of the manganese dioxide coarse powder through a spray granulator to obtain manganese dioxide fine powder with a D50 particle size of 1 μm. Among them, the conditions for spray granulation include: the feeding rate is 5 m 3 / min, the inlet air temperature is 120 °C, the outlet air temperature is 60 °C, and the pressure is 1.5 Mpa.

[0063] (2) Add the nickel oxide fine powder, cobalt oxide fine powder, and manganese dioxide fine powder obtained in step (1) to a high-speed mixer and premix evenly. Then, weigh 670 g of lithium carbonate and 106 g of sodium carbonate powder and add them to the high-speed mixer to continue mixing evenly. Then, place the evenly mixed system in a corundum crucible and conduct high-temperature calcination in a roller hearth kiln. Maintain an oxygen atmosphere during calcination, the calcination temperature is 870 °C, and the calcination duration is 12 h. Then, pulverize and screen the calcined product to obtain Li 0.9 Na 0.1 (Ni 0.8 Co 0.1 Mn 0.1 )O2 lithium-sodium composite cathode material.

[0064] Example 2

[0065] This example provides a lithium-sodium composite cathode material and its preparation method. The lithium-sodium composite cathode material is Li 0.9 Na 0.1 (Ni 0.6 Co 0.1 Mn 0.3 )O2, and the preparation method includes the following steps:

[0066] (1) Weigh 450 g of nickel oxide and place it in a high-energy ball mill. Ball mill it at a speed of 60 rpm for 1 h to obtain nickel oxide coarse powder with a D50 particle size of 5 μm. Then, place the nickel oxide coarse powder in 900 mL of water and stir to mix evenly to obtain a suspension of the nickel oxide coarse powder. Spray granulate the suspension of the nickel oxide coarse powder through a spray granulator to obtain nickel oxide fine powder with a D50 particle size of 1 μm. Among them, the conditions for spray granulation include: the feeding rate is 5 m 3 / min, the inlet air temperature is 120 °C, the outlet air temperature is 60 °C, and the pressure is 1.5 Mpa;

[0067] Weigh 166 g of cobalt oxide and place it in a high-energy ball mill. Ball mill it at a speed of 60 rpm for 1.2 h to obtain cobalt oxide coarse powder with a D50 particle size of 5 μm. Then place the cobalt oxide coarse powder in 332 mL of water and stir to mix evenly to obtain a suspension of cobalt oxide coarse powder. Spray granulate the suspension of cobalt oxide coarse powder through a spray granulator to obtain cobalt oxide fine powder with a D50 particle size of 1 μm. Among them, the conditions for spray granulation include: the feeding rate is 5 m 3 / min, the inlet air temperature is 120 °C, the outlet air temperature is 60 °C, and the pressure is 1.5 Mpa;

[0068] Weigh 261 g of manganese dioxide and place it in a high-energy ball mill. Ball mill it at a speed of 60 rpm for 0.8 h to obtain manganese dioxide coarse powder with a D50 particle size of 5 μm. Then place the manganese dioxide coarse powder in 522 mL of water and stir to mix evenly to obtain a suspension of manganese dioxide coarse powder. Spray granulate the suspension of manganese dioxide coarse powder through a spray granulator to obtain manganese dioxide fine powder with a D50 particle size of 1 μm. Among them, the conditions for spray granulation include: the feeding rate is 5 m 3 / min, the inlet air temperature is 120 °C, the outlet air temperature is 60 °C, and the pressure is 1.5 Mpa.

[0069] (2) Add the nickel oxide fine powder, cobalt oxide fine powder, and manganese dioxide fine powder obtained in step (1) to a high-speed mixer and premix them evenly. Then weigh 670 g of lithium carbonate and 106 g of sodium carbonate powder and add them to the high-speed mixer to continue mixing evenly. Then place the evenly mixed system in a corundum crucible and conduct high-temperature calcination in a roller hearth kiln. Maintain an oxygen atmosphere during calcination, the calcination temperature is 900 °C, and the calcination duration is 12 h. Then pulverize and sieve the calcined product to obtain Li 0.9 Na 0.1 (Ni 0.6 Co 0.1 Mn 0.3 )O2 lithium-sodium composite cathode material.

[0070] Example 3

[0071] This example refers to the preparation method of Example 1, with the only difference being that step (1) is different.

[0072] Step (1) of this example is as follows:

[0073] (1) Weigh 944 g of nickel carbonate and place it in a high-energy ball mill. Ball mill it at a speed of 50 rpm for 1 h to obtain nickel carbonate coarse powder with a D50 particle size of 5 μm. Then place the nickel carbonate coarse powder in 1888 mL of water and stir to mix evenly to obtain a suspension of nickel carbonate coarse powder. Spray granulate the suspension of nickel carbonate coarse powder through a spray granulator to obtain nickel carbonate fine powder with a D50 particle size of 1 μm. Among them, the conditions for spray granulation include: the feeding rate is 5 m3 / min, the inlet air temperature is 120 °C, the outlet air temperature is 60 °C, and the pressure is 1.5 Mpa;

[0074] Weigh 114 g of cobalt carbonate and place it in a high-energy ball mill. Ball mill it at a speed of 50 rpm for 1.2 h to obtain cobalt carbonate coarse powder with a D50 particle size of 5 μm. Then place the cobalt carbonate coarse powder in 228 mL of water, stir and mix evenly to obtain a suspension of cobalt carbonate coarse powder. Spray granulate the suspension of cobalt carbonate coarse powder through a spray granulator to obtain cobalt carbonate fine powder with a D50 particle size of 1 μm. Among them, the conditions for spray granulation include: the feeding rate is 5 m 3 / min, the inlet air temperature is 120 °C, the outlet air temperature is 60 °C, and the pressure is 1.5 Mpa;

[0075] Weigh 115 g of manganese carbonate and place it in a high-energy ball mill. Ball mill it at a speed of 50 rpm for 0.8 h to obtain manganese carbonate coarse powder with a D50 particle size of 5 μm. Then place the manganese carbonate coarse powder in 230 mL of water, stir and mix evenly to obtain a suspension of manganese carbonate coarse powder. Spray granulate the suspension of manganese carbonate coarse powder through a spray granulator to obtain manganese carbonate fine powder with a D50 particle size of 1 μm. Among them, the conditions for spray granulation include: the feeding rate is 5 m 3 / min, the inlet air temperature is 120 °C, the outlet air temperature is 60 °C, and the pressure is 1.5 Mpa.

[0076] Example 4

[0077] This example refers to the preparation method of Example 2, with the only difference being that step (1) is different.

[0078] Step (1) of this example is as follows:

[0079] (1) Weigh 708 g of nickel carbonate and place it in a high-energy ball mill. Ball mill it at a speed of 50 rpm for 1 h to obtain nickel carbonate coarse powder with a D50 particle size of 5 μm. Then place the nickel carbonate coarse powder in 1416 mL of water, stir and mix evenly to obtain a suspension of nickel carbonate coarse powder. Spray granulate the suspension of nickel carbonate coarse powder through a spray granulator to obtain nickel carbonate fine powder with a D50 particle size of 1 μm. Among them, the conditions for spray granulation include: the feeding rate is 5 m 3 / min, the inlet air temperature is 120 °C, the outlet air temperature is 60 °C, and the pressure is 1.5 Mpa;

[0080] Weigh 114 g of cobalt carbonate and place it in a high-energy ball mill. Ball mill at a speed of 50 rpm for 1.2 h to obtain cobalt carbonate coarse powder with a D50 particle size of 5 μm. Then place the cobalt carbonate coarse powder in 228 mL of water and stir to mix evenly to obtain a suspension of cobalt carbonate coarse powder. Spray granulate the suspension of cobalt carbonate coarse powder through a spray granulator to obtain cobalt carbonate fine powder with a D50 particle size of 1 μm. Among them, the conditions for spray granulation include: the feeding rate is 5 m 3 / min, the inlet air temperature is 120 °C, the outlet air temperature is 60 °C, and the pressure is 1.5 Mpa;

[0081] Weigh 345 g of manganese carbonate and place it in a high-energy ball mill. Ball mill at a speed of 50 rpm for 0.8 h to obtain manganese carbonate coarse powder with a D50 particle size of 5 μm. Then place the manganese carbonate coarse powder in 690 mL of water and stir to mix evenly to obtain a suspension of manganese carbonate coarse powder. Spray granulate the suspension of manganese carbonate coarse powder through a spray granulator to obtain manganese carbonate fine powder with a D50 particle size of 1 μm. Among them, the conditions for spray granulation include: the feeding rate is 5 m 3 / min, the inlet air temperature is 120 °C, the outlet air temperature is 60 °C, and the pressure is 1.5 Mpa.

[0082] Example 5

[0083] This example refers to the preparation method of Example 1, the only difference being that in step (1), the conditions for spray granulation are different, and the D50 particle sizes of the nickel oxide fine powder, cobalt oxide fine powder, and manganese dioxide fine powder obtained are different.

[0084] The conditions for spray granulation of the nickel oxide fine powder include: the feeding rate is 3 m 3 / min, the inlet air temperature is 120 °C, the outlet air temperature is 60 °C, and the pressure is 1.5 Mpa, to obtain nickel oxide fine powder with a D50 particle size of 0.5 μm; the conditions for spray granulation of the cobalt oxide fine powder include: the feeding rate is 3 m 3 / min, the inlet air temperature is 120 °C, the outlet air temperature is 60 °C, and the pressure is 1.5 Mpa, to obtain cobalt oxide fine powder with a D50 particle size of 0.5 μm; the conditions for spray granulation of the manganese dioxide fine powder include: the feeding rate is 3 m 3 / min, the inlet air temperature is 120 °C, the outlet air temperature is 60 °C, and the pressure is 1.5 Mpa, to obtain manganese dioxide fine powder with a D50 particle size of 0.5 μm.

[0085] Example 6

[0086] This example refers to the preparation method of Example 1, the only difference being that in step (1), the conditions for spray granulation are different, and the D50 particle sizes of the nickel oxide fine powder, cobalt oxide fine powder, and manganese dioxide fine powder obtained are different.

[0087] The spray granulation conditions of nickel oxide micropowder include: the feeding rate is 5 m 3 / min, the inlet air temperature is 120 °C, the outlet air temperature is 60 °C, the pressure is 1.3 Mpa, and nickel oxide micropowder with a D50 particle size of 2 μm is obtained; the spray granulation conditions of cobalt oxide micropowder include: the feeding rate is 5 m 3 / min, the inlet air temperature is 120 °C, the outlet air temperature is 60 °C, the pressure is 1.3 Mpa, and cobalt oxide micropowder with a D50 particle size of 2 μm is obtained; the spray granulation conditions of manganese dioxide micropowder include: the feeding rate is 5 m 3 / min, the inlet air temperature is 120 °C, the outlet air temperature is 60 °C, the pressure is 1.3 Mpa, and manganese dioxide micropowder with a D50 particle size of 2 μm is obtained.

[0088] Example 7

[0089] This example refers to the preparation method of Example 1, the only difference being that in step (1), the spray granulation conditions are different, and the D50 particle sizes of the obtained nickel oxide micropowder, cobalt oxide micropowder, and manganese dioxide micropowder are different.

[0090] The spray granulation conditions of nickel oxide micropowder include: the feeding rate is 2 m 3 / min, the inlet air temperature is 120 °C, the outlet air temperature is 60 °C, the pressure is 1.5 Mpa, and nickel oxide micropowder with a D50 particle size of 0.3 μm is obtained; the spray granulation conditions of cobalt oxide micropowder include: the feeding rate is 2 m 3 / min, the inlet air temperature is 120 °C, the outlet air temperature is 60 °C, the pressure is 1.5 Mpa, and cobalt oxide micropowder with a D50 particle size of 0.3 μm is obtained; the spray granulation conditions of manganese dioxide micropowder include: the feeding rate is 2 m 3 / min, the inlet air temperature is 120 °C, the outlet air temperature is 60 °C, the pressure is 1.5 Mpa, and manganese dioxide micropowder with a D50 particle size of 0.3 μm is obtained.

[0091] Example 8

[0092] This example refers to the preparation method of Example 1, the only difference being that in step (1), the spray granulation conditions are different, and the D50 particle sizes of the obtained nickel oxide micropowder, cobalt oxide micropowder, and manganese dioxide micropowder are different.

[0093] The spray granulation conditions of nickel oxide micropowder include: the feeding rate is 5 m 3 / min, the inlet air temperature is 120 °C, the outlet air temperature is 60 °C, the pressure is 1.1 Mpa, and nickel oxide micropowder with a D50 particle size of 3 μm is obtained; the spray granulation conditions of cobalt oxide micropowder include: the feeding rate is 5 m 3 / min, the inlet air temperature is 120 °C, the outlet air temperature is 60 °C, the pressure is 1.1 Mpa, and cobalt oxide micropowder with a D50 particle size of 3 μm is obtained; the spray granulation conditions of manganese dioxide micropowder include a feeding rate of: 5 m 3 / min, the inlet air temperature is 120 °C, the outlet air temperature is 60 °C, the pressure is 1.1 Mpa, and manganese dioxide micropowder with a D50 particle size of 3 μm is obtained.

[0094] Example 9

[0095] This example refers to the preparation method of Example 1, the only difference is that in step (2), the calcination temperature is 860 °C and the calcination time is 16 h.

[0096] Example 10

[0097] This example refers to the preparation method of Example 1, the only difference is that in step (2), the calcination temperature is 920 °C and the calcination time is 8 h.

[0098] Example 11

[0099] This example refers to the preparation method of Example 1, the only difference is that in step (2), the calcination temperature is 850 °C and the calcination time is 12 h.

[0100] Example 12

[0101] This example refers to the preparation method of Example 1, the only difference is that in step (2), the calcination temperature is 930 °C and the calcination time is 12 h.

[0102] Comparative Example 1

[0103] Comparative Example 1 provides a conventional preparation method of NCM811 cathode material, including the following steps:

[0104] Accurately weigh 0.48 mol of Ni(NO3)2·6H2O, 0.06 mol of Co(NO3)2·6H2O, and 0.06 mol of Mn(NO3)2·6H2O, and dissolve them in 3 L of deionized water. Stir to completely dissolve the three to obtain a mixed metal salt solution. Subsequently, weigh 40 g of flaky sodium hydroxide and add it to the aforementioned mixed metal salt solution, and stir to completely dissolve it. Continuously add 4 mol / L ammonia water solution to adjust the pH of the solution to be stable at 11, stir to make the system evenly distributed, and continuously react for 12 h, maintaining a constant temperature of 60 °C during the reaction. After the reaction is completed, filter and separate the solid precipitation product, and wash it with clear water to remove the remaining impurity ions to obtain the NCM811 cathode material precursor. Mix lithium carbonate and the precursor evenly according to a molar ratio of 1:2.02, and then calcine it in a tube furnace at 750 °C in an oxygen atmosphere for 8 h to obtain the NCM811 cathode material.

[0105] Comparative Example 2

[0106] Comparative Example 2 provides a conventional preparation method for NCM613 cathode material, including the following steps:

[0107] Accurately weigh 0.36 mol of Ni(NO3)2·6H2O, 0.06 mol of Co(NO3)2·6H2O, and 0.186 mol of Mn(NO3)2·6H2O, and dissolve them in 3 L of deionized water. Stir to completely dissolve the three to obtain a mixed metal salt solution. Subsequently, weigh 40 g of flaky sodium hydroxide and add it to the aforementioned mixed metal salt solution, and stir to completely dissolve it. Continuously add 4 mol / L ammonia water solution to adjust the pH of the solution to be stable at 11, stir to make the system evenly distributed, and continuously react for 12 h, maintaining a constant temperature of 60 °C during the reaction. After the reaction is completed, filter and separate the solid precipitation product, and wash it with clear water to remove the remaining impurity ions to obtain the NCM613 cathode material precursor. Mix lithium carbonate and the precursor evenly according to a molar ratio of 1:2.02, and then calcine it in a tube furnace at 800 °C in an oxygen atmosphere for 8 h to obtain the NCM613 cathode material.

[0108] Comparative Example 3

[0109] Comparative Example 3 provides a preparation method for cathode material, including the following steps:

[0110] (1) Weigh 600 g of nickel oxide and place it in a high-energy ball mill, and ball mill it at a rotation speed of 60 rpm for 1 h to obtain nickel oxide coarse powder with a D50 particle size of 5 μm; weigh 166 g of cobalt oxide and place it in a high-energy ball mill, and ball mill it at a rotation speed of 60 rpm for 1.2 h to obtain cobalt oxide coarse powder with a D50 particle size of 5 μm; weigh 87 g of manganese dioxide and place it in a high-energy ball mill, and ball mill it at a rotation speed of 60 rpm for 0.8 h to obtain manganese dioxide coarse powder with a D50 particle size of 5 μm.

[0111] (2) Add the obtained crude nickel oxide powder, crude cobalt oxide powder, and crude manganese dioxide powder in step (1) to a high-speed mixer for uniform premixing, and then weigh 670 g of lithium carbonate and 106 g of sodium carbonate powder and add them to the high-speed mixer for continuous mixing until uniform. Then place the uniformly mixed system in a corundum crucible and conduct high-temperature calcination in a roller hearth kiln. During calcination, maintain an oxygen atmosphere, the calcination temperature is 870 °C, and the calcination duration is 12 h. Then pulverize and screen the calcined product to obtain the cathode material.

[0112] Comparative Example 4

[0113] Comparative Example 4 provides a preparation method of a lithium-sodium composite cathode material, including the following steps:

[0114] (1) Weigh 600 g of nickel oxide and place it in a high-energy ball mill, and ball mill at a speed of 60 rpm for 1 h to obtain a crude nickel oxide powder with a D50 particle size of 5 μm; weigh 166 g of cobalt oxide and place it in a high-energy ball mill, and ball mill at a speed of 60 rpm for 1.2 h to obtain a crude cobalt oxide powder with a D50 particle size of 5 μm; weigh 87 g of manganese dioxide and place it in a high-energy ball mill, and ball mill at a speed of 60 rpm for 0.8 h to obtain a crude manganese dioxide powder with a D50 particle size of 5 μm.

[0115] (2) Add the obtained crude nickel oxide powder, crude cobalt oxide powder, and crude manganese dioxide powder in step (1) to a high-speed mixer for uniform premixing, and then weigh 106 g of sodium carbonate powder and add it to the high-speed mixer for continuous mixing until uniform. Then place the uniformly mixed system in a corundum crucible and conduct high-temperature calcination in a roller hearth kiln. During calcination, maintain an oxygen atmosphere, the calcination temperature is 870 °C, and the calcination duration is 8 h; subsequently, uniformly mix the calcined product with 670 g of lithium carbonate and continue to calcine at 710 °C for 8 h. Finally, pulverize and screen the calcined product to obtain the cathode material.

[0116] Experimental Example 1

[0117] Refer to the method of GB / T 37201-2018 to test the initial discharge specific capacity of the cathode materials of Examples 1 to 12 and Comparative Examples 1 to 4 at a 0.1C rate, and refer to the method of GB / T 37207-2018 to test the capacity retention rate of the cathode materials of Examples 1 to 12 and Comparative Examples 1 to 4 after 50 cycles of charge and discharge at a 1C rate. The test results are shown in Table 1.

[0118] Table 1 Test results of cathode materials of different examples and comparative examples

[0119]

[0120]

[0121] As can be seen from Table 1, compared with the pure lithium ternary materials prepared in Comparative Example 1 and Comparative Example 2, the lithium-sodium composite cathode material obtained by the preparation method of the present invention has no disadvantages in terms of specific capacity and cycle capacity rate. Moreover, the production process is greatly simplified, the raw material cost is reduced, the watt-hour cost of the material is significantly reduced, and the market competitiveness of the lithium-sodium composite cathode material is significantly improved.

[0122] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a lithium-sodium composite cathode material, characterized in that, It includes the following steps: (a) Respectively ball-mill the nickel source, cobalt source and manganese source to obtain nickel source coarse powder, cobalt source coarse powder and manganese source coarse powder. Disperse the nickel source coarse powder, the cobalt source coarse powder and the manganese source coarse powder in a solvent respectively, and then perform spray granulation respectively to obtain nickel source fine powder, cobalt source fine powder and manganese source fine powder; (b) After mixing the nickel source fine powder, the cobalt source fine powder and the manganese source fine powder with a lithium source and a sodium source, perform a calcination treatment.

2. The preparation method of the lithium-sodium composite cathode material according to claim 1, characterized in that, The D50 particle sizes of the nickel source coarse powder, the cobalt source coarse powder and the manganese source coarse powder are independently selected from 3 to 10 μm.

3. The preparation method of the lithium-sodium composite cathode material according to claim 1, wherein, The rotation speed of the ball-milling treatment is 40 to 80 r / min, and the time of the ball-milling treatment is 0.5 to 2 h.

4. The preparation method of the lithium-sodium composite cathode material according to claim 1, characterized in that, The D50 particle sizes of the nickel source fine powder, the cobalt source fine powder and the manganese source fine powder are independently selected from 0.5 to 2 μm.

5. The preparation method of the lithium-sodium composite cathode material according to claim 1, wherein, The solvent includes at least one of water and ethanol.

6. The preparation method of the lithium-sodium composite cathode material according to claim 1, wherein, The dispersion concentrations of the nickel source coarse powder, the cobalt source coarse powder and the manganese source coarse powder in the solvent are independently selected from 30% to 35%.

7. The preparation method of the lithium-sodium composite cathode material according to claim 1, characterized in that, The conditions for the spray granulation include: the feeding rate is 3 - 5 m 3 / min, the inlet air temperature is 100 - 120 °C, the outlet air temperature is 40 - 60 °C, and the pressure is 1.3 - 1.5 Mpa.

8. The preparation method of the lithium-sodium composite cathode material according to claim 1, wherein The nickel source is nickel oxide or nickel carbonate, the cobalt source is cobalt oxide or cobalt carbonate, and the manganese source is manganese oxide or manganese carbonate.

9. The preparation method of the lithium-sodium composite cathode material according to claim 1, characterized in that, The lithium source is at least one of lithium carbonate, lithium hydroxide and lithium chloride; the sodium source is at least one of sodium carbonate, sodium hydroxide and sodium chloride.

10. The preparation method of the lithium-sodium composite cathode material according to claim 1, characterized in that, The temperature of the calcination treatment is 860 to 920 °C, and the time of the calcination treatment is 8 to 16 h.

11. The preparation method of the lithium-sodium composite cathode material according to claim 1, wherein, The atmosphere of the calcination treatment is an oxygen atmosphere.

12. The preparation method of the lithium-sodium composite cathode material according to claim 1, wherein, The chemical formula of the lithium-sodium composite cathode material is Na x Li 1-x (Ni y Co z Mn 1-y-z )O2, where 0 < x < 0.2, 0 < y < 0.9, 0 < z ≤ 0.

1.

13. A lithium-sodium composite cathode material prepared by the preparation method of the lithium-sodium composite cathode material according to any one of claims 1 to 12.

14. A lithium-ion battery, characterized in that, It includes the lithium-sodium composite cathode material prepared by the preparation method of the lithium-sodium composite cathode material according to any one of claims 1 to 12 or the lithium-sodium composite cathode material according to claim 13.

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