Method for producing three-component mixed-phase cathode materials
Patent Information
- Application Number
- VN1202509612
- Authority / Receiving Office
- VN · VN
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2024-11-29
- Filing Date
- 2025-08-29
- Publication Date
- 2026-07-15
AI Technical Summary
Existing lithium-ion battery cathode materials suffer from cycling stability and capacity decay issues at high charging cutoff voltages. In particular, O3 phase materials perform poorly under long cycles, and lithium cobalt oxide is expensive and its capacity and cycle performance are not as good as ternary cathode materials.
By mixing the ternary cathode material precursor with lithium, sodium, and cobalt sources, and carrying out sintering, calcination, and ion exchange reactions, a composite phase ternary cathode material is formed. The material is then coated with a coating agent to form an O3 and O2 coexisting phase, adjusting the lithium ion radius to adapt to the material, avoiding the disadvantages caused by sodium ions, and enhancing the material stability and lithium ion transport.
It improves the specific capacity, coulombic efficiency, and cycle performance of the cathode material, enhances the structural stability of the battery, avoids metal ion dissolution and interfacial redox reactions, and improves the battery's electrical performance.
Smart Images
Figure VN1202509612_0
Abstract
Description
A composite phase ternary cathode material, its preparation method and application Technical Field
[0001] This application belongs to the field of cathode material technology, specifically relating to a composite phase ternary cathode material, its preparation method and application. Background Technology
[0002] The market demand for higher energy density in lithium-ion batteries is constantly increasing, and there is an urgent need for a method to improve the energy density of lithium-ion batteries.
[0003] Lithium cobalt oxide (LiCO) offers high energy density batteries, but as the charging cutoff voltage increases, the O3 phase structure becomes highly unstable at ultra-high charging cutoff voltages. Some researchers have attempted to improve the capacity and cycle stability of cathode materials by blending O2 and O3 phase materials in a certain ratio. However, the disadvantages of O3 phase materials at high charging cutoff voltages become increasingly apparent with increasing cycle counts, leading to accelerated capacity decay and deteriorating battery performance over long cycles. Other researchers have directly sintered sodium-containing compounds and then ion-exchanged them with lithium, using LiCO directly as the cathode. However, this approach suffers from high cost and inferior capacity and cycle performance compared to ternary cathode materials. Summary of the Invention
[0004] Therefore, this application provides a composite phase ternary cathode material, its preparation method and application, thereby overcoming the shortcomings of insufficient capacity and cycle performance improvement of cathode materials in the prior art.
[0005] In a first aspect, this application provides a method for preparing a composite phase ternary cathode material, wherein the preparation method includes the following steps:
[0006] S1, the ternary cathode material precursor is mixed with the first lithium source and sintered to obtain a sintered product;
[0007] S2, the first calcined product, sodium source, and cobalt source are mixed and calcined to obtain the second calcined product;
[0008] S3, the calcined product and the second lithium source are mixed and subjected to an ion exchange reaction to obtain a composite ternary cathode material.
[0009] In this application, XRD tests were performed to prove that a phase transition occurred.
[0010] In this application, the first lithium source and the second lithium source are conventional lithium sources in the art. Typically, without limitation, the first lithium source and the second lithium source each independently include at least one of lithium carbonate or lithium hydroxide.
[0011] In this application, the molar ratio of lithium in the lithium source to the total metal elements in the ternary cathode material precursor is 1.04-1.06:1; the metal elements in the ternary cathode material precursor refer to nickel, cobalt and manganese.
[0012] In this application, the mixing is a conventional mixing method in the art, which is sufficient to achieve uniform mixing.
[0013] According to this application, the sintering conditions include: a sintering temperature of 900-1000℃ and a sintering time of 8-12h; the calcination conditions include: a calcination temperature of 600-750℃ and a calcination time of 6-10h.
[0014] According to this application, the ion exchange reaction further includes mixing the ion exchange product with a coating agent, coating the product, and then sintering it.
[0015] In this application, the sintering after coating is a conventional sintering process in the art. Typically, without limitation, the conditions for sintering after coating include: a sintering temperature of 300-500℃ and a sintering time of 4-8h.
[0016] According to this application, the molar ratio of the total metal elements in the ternary cathode material precursor to the total metal elements in the coating agent is 1:(0.001-0.006).
[0017] According to this application, the coating agent includes at least one of an aluminum source or a tungsten source.
[0018] According to this application, the aluminum source includes at least one of aluminum oxide, aluminum hydroxide, or aluminum inorganic salt; more preferably, the aluminum source includes at least one of aluminum oxide, aluminum hydroxide, aluminum sulfate, aluminum chloride, or aluminum nitrate.
[0019] According to this application, the tungsten source includes at least one of tungsten oxide, tungstic acid, or tungstate; more preferably, the tungsten source includes at least one of tungsten oxide, tungstic acid, or ammonium paratungstate.
[0020] According to this application, when the coating agent is an aluminum source and a tungsten source, the molar ratio of aluminum in the aluminum source to tungsten in the tungsten source is (2-5):1.
[0021] According to this application, in S2, the total amount of metal ions in the ternary cathode material precursor and the molar ratio of sodium in the sodium source to cobalt in the cobalt source are 1:(0.007-0.012):(0.01-0.015).
[0022] According to this application, the sodium source includes sodium-containing salts and / or sodium-containing bases; further optionally, the sodium source includes at least one of sodium carbonate, sodium bicarbonate, or sodium hydroxide.
[0023] According to this application, the cobalt source includes at least one of cobalt oxide or cobalt hydroxide; more preferably, the cobalt source includes at least one of cobalt oxide, cobalt hydroxyoxide or cobalt hydroxide.
[0024] According to this application, the molar ratio of lithium in the second lithium source to sodium in the sodium source is 1-10:1.
[0025] According to this application, the conditions for the ion exchange reaction include: a temperature of 200-400°C and a time of 1-8 hours.
[0026] According to this application, the temperature of the ion exchange reaction is 250-380℃ and the time is 2-6h.
[0027] Secondly, this application provides a composite phase ternary cathode material prepared by the preparation method described in the first aspect.
[0028] Thirdly, this application provides a secondary battery, the secondary battery comprising the composite phase ternary cathode material described in the second aspect.
[0029] In this application, the battery preparation method is as follows: A positive electrode slurry is prepared by mixing positive electrode material, polyvinylidene fluoride (PVDF), and acetylene black in a mass ratio of 96:(2-2.5):(2-2.5) with N-methylpyrrolidone (NMP), wherein the mass ratio of solid to liquid is 7:(2.5-3.5); a negative electrode slurry is prepared by uniformly mixing negative electrode material graphite, binder LA133, and carbon nanotubes (CNTs) in a mass ratio of 92:(5-6):(2-2.5); and a mixed negative electrode slurry is prepared by processing the positive and negative electrode slurries through coating, rolling, slicing, winding, assembly, liquid injection, formation, secondary sealing, and capacity testing.
[0030] The technical solution of this application has the following advantages:
[0031] 1. This application provides a method for preparing a composite phase ternary cathode material, wherein the preparation method includes the following steps: S1, mixing a ternary cathode material precursor with a first lithium source and sintering to obtain a calcined product; S2, mixing the calcined product, a sodium source, and a cobalt source and calcining to obtain a second calcined product; S3, mixing the second calcined product and a second lithium source and performing an ion exchange reaction to obtain a composite phase ternary cathode material; wherein the calcined product is an O3 phase, and after adding the sodium source and cobalt source, the sodium source and cobalt source exist as coating materials at the interface of the O3 phase, and then a P2 phase coating material is formed at the interface of the O3 phase material, and then an ion exchange reaction is performed, in which lithium ions and sodium ions undergo ion exchange to obtain an O3 and O2 coexisting phase, because sodium ions and lithium ions... The radii of sodium ions are different; sodium ions are about 25% larger than lithium ions, making the insertion and extraction processes of sodium ions in materials more complex. After ion exchange, the material layers are simultaneously adjusted to accommodate the new radii of lithium ions, avoiding the disadvantages of sodium ions. During use, after lithium ions dissolve under high voltage, the cathode material structure adapted to lithium ions maintains the stability of the coexisting O3 and O2 phases after the lithium ions are removed, thus ensuring the structural stability of the material. In addition, the presence of the O2 phase can effectively alleviate the dissolution of metal ions and avoid strong redox reactions at the interface layer, thereby improving the stability of the battery cathode material interface. The O2 phase can also accelerate the transport of lithium ions, resulting in the cathode material exhibiting excellent specific capacity, coulombic efficiency, and cycle performance.
[0032] 2. The addition of a coating agent in this application can coat the ion exchange products, isolate them from the electrolyte, and further improve the electrical performance of the cathode material.
[0033] 3. The specific molar ratio of the total metal elements in the ternary cathode material precursor to the total metal elements in the coating agent, the specific type of coating agent, the specific molar ratio of the total metal ions in the ternary cathode material precursor, the sodium element in the sodium source and the cobalt element in the cobalt source, and the specific types of sodium and cobalt sources in this application can all further improve the specific capacity, coulombic efficiency and cycle performance of the cathode material.
[0034] 4. The specific ion exchange conditions in this application can further optimize the reaction effect, thereby further improving the electrical performance of the prepared cathode material. Attached Figure Description
[0035] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0036] Figure 1 is an XRD image of the composite phase ternary cathode material prepared in Example 1;
[0037] Figure 2 is an electron microscope image of the composite phase ternary cathode material prepared in Example 1. Detailed Implementation
[0038] The following embodiments are provided to better understand this application and are not limited to the preferred embodiments described herein. They do not constitute a limitation on the content and scope of protection of this application. Any product that is the same as or similar to this application, derived by anyone under the guidance of this application or by combining features of this application with other prior art, falls within the scope of protection of this application.
[0039] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.
[0040] Example 1
[0041] This embodiment provides a method for preparing a composite phase ternary cathode material, as detailed below:
[0042] S1, a ternary cathode material precursor and lithium carbonate are mixed and sintered to obtain a product with the chemical formula Li. 1.04 Ni 0.60 Co 0.10 Mn 0.30 The sintering product is calcined in O2; the molar ratio of lithium in lithium carbonate to the total amount of nickel, cobalt and manganese in the ternary cathode material precursor is 1.04:1; sintering is carried out in an oxygen atmosphere at a temperature of 940℃ for 10 hours.
[0043] S2, the first calcined product, cobalt hydroxide, and sodium carbonate are mixed and calcined to obtain the second calcined product; wherein, the molar ratio of the total amount of nickel, cobalt, and manganese in the ternary cathode material precursor, the molar ratio of sodium in sodium carbonate, and the molar ratio of cobalt in cobalt hydroxide are 1:0.009:0.013; the calcination is carried out in an oxygen atmosphere at a temperature of 750℃ for 8 hours;
[0044] S3, calcined product and lithium hydroxide are mixed and subjected to an ion exchange reaction to obtain an ion exchange product; wherein, the molar ratio of lithium element in lithium hydroxide to sodium element in sodium carbonate is 3:1; the temperature of the ion exchange reaction is 280℃ and the time is 3h.
[0045] S4. The ion exchange product was mixed with aluminum oxide and tungsten oxide as coating agents, coated, and then sintered to obtain a composite ternary cathode material. The molar ratio of the total nickel, cobalt, and manganese elements in the ternary cathode precursor to the total metal elements in the coating agent was 1:0.004, and the molar ratio of aluminum to tungsten in the coating agent was 3:1. Sintering after coating was carried out in an oxygen atmosphere at a temperature of 400℃ for 6 hours. The XRD image of the composite ternary cathode material is shown in Figure 1. Figure 1 shows the formation of O3 and O2 composite phases. The position of the O2 phase diffraction peak corresponds to the standard card PDF#54-0894, and the position of the O3 phase diffraction peak corresponds to the standard card PDF#85-1979. The electron microscope image of the composite ternary cathode material is shown in Figure 2. Figure 2 shows that the cathode material has saturated single crystal particles, a relatively smooth interface, and is easily dispersed.
[0046] Example 2
[0047] This embodiment provides a method for preparing a composite phase ternary cathode material, as detailed below:
[0048] S1, a ternary cathode material precursor and lithium carbonate are mixed and sintered to obtain a product with the chemical formula Li. 1.04 Ni 0.60 Co 0.10 Mn 0.30 The sintering product is calcined in O2; the molar ratio of lithium in lithium carbonate to the total amount of nickel, cobalt and manganese in the ternary cathode material precursor is 1.05:1; sintering is carried out in an oxygen atmosphere at a temperature of 950℃ for 10 hours.
[0049] S2, the first calcined product, cobalt hydroxide, and sodium carbonate are mixed and calcined to obtain the second calcined product; wherein, the total amount of nickel, cobalt, and manganese in the ternary cathode material precursor, and the molar ratio of sodium in sodium carbonate to cobalt in cobalt hydroxide are 1:0.009:0.013; the calcination is carried out in an oxygen atmosphere at a temperature of 700℃ for 8 hours;
[0050] S3, the dicalcined product and lithium hydroxide are mixed and subjected to an ion exchange reaction to obtain the ion exchange product; wherein the molar ratio of lithium element in lithium hydroxide to sodium element in sodium carbonate is 4:1; the temperature of the ion exchange reaction is 280℃ and the time is 2h.
[0051] S4. The ion exchange product is mixed with aluminum oxide and tungsten oxide as coating agents, coated, and then sintered to obtain a composite ternary cathode material. The molar ratio of the total metal elements of nickel, cobalt, and manganese in the ternary cathode material precursor to the total metal elements in the coating agent is 1:0036, and the molar ratio of aluminum to tungsten in the coating agent is 2:1. The sintering after coating is carried out in an oxygen atmosphere at a temperature of 450℃ for 6 hours.
[0052] Example 3
[0053] This embodiment provides a method for preparing a composite phase ternary cathode material, as detailed below:
[0054] The method is the same as in Example 1, except that step S4 is omitted, and the resulting ion exchange product is the composite phase ternary cathode material.
[0055] Example 4
[0056] This embodiment provides a method for preparing a composite phase ternary cathode material, as detailed below:
[0057] The difference from Example 1 is that in S4, the ion exchange product, alumina and alumina are mixed, coated and sintered to obtain a composite ternary cathode material; wherein, the molar ratio of the total metal elements of nickel, cobalt and manganese in the ternary cathode material precursor to the total metal elements in the coating agent is 1:0.004, and the molar ratio of aluminum and tungsten in the coating agent is 3:1.
[0058] Example 5
[0059] This embodiment provides a method for preparing a composite phase ternary cathode material, as detailed below:
[0060] The difference from Example 1 is that in S4, the coating agent is tungsten oxide, and the molar ratio of the total amount of nickel, cobalt and manganese elements in the ternary cathode material precursor to the tungsten element in the tungsten oxide is 1:0.004.
[0061] Example 6
[0062] This embodiment provides a method for preparing a composite phase ternary cathode material, as detailed below:
[0063] The difference from Example 1 is that in S2, the total amount of nickel, cobalt and manganese in the ternary cathode material precursor, and the molar ratio of sodium in sodium carbonate to cobalt in cobalt hydroxide are 1:0.01:0.012.
[0064] Example 7
[0065] This embodiment provides a method for preparing a composite phase ternary cathode material, as detailed below:
[0066] The difference from Example 1 is that in S2, the temperature of the ion exchange reaction is 200°C and the time is 1 hour.
[0067] Comparative Example 1
[0068] This comparative example provides a method for preparing a ternary cathode material, as detailed below:
[0069] A ternary cathode material precursor was mixed with lithium carbonate and sintered to obtain a product with the chemical formula Li. 1.04 Ni 0.60 Co 0.10 Mn 0.30 The sintering process was carried out under an oxygen atmosphere at a temperature of 940°C for 10 hours to obtain the ternary cathode material. The molar ratio of lithium in lithium carbonate to the total amount of nickel, cobalt, and manganese in the ternary cathode material precursor was 1.04:1.
[0070] Comparative Example 2
[0071] This comparative example provides a method for preparing a ternary cathode material, as detailed below:
[0072] S1, a ternary cathode material precursor and lithium carbonate are mixed and sintered to obtain a product with the chemical formula Li. 1.04 Ni 0.60 Co 0.10 Mn 0.30 The sintering product is calcined in O2; the molar ratio of lithium in lithium carbonate to the total amount of nickel, cobalt and manganese in the ternary cathode material precursor is 1.04:1; sintering is carried out in an oxygen atmosphere at a temperature of 940℃ for 10 hours.
[0073] S2, a first-burned product, cobalt hydroxide, and sodium carbonate are mixed and calcined to obtain a second-burned product; wherein, the total amount of nickel, cobalt, and manganese in the ternary cathode material precursor, and the molar ratio of sodium in sodium carbonate to cobalt in cobalt hydroxide are 1:0.009:0.013; the calcination is carried out in an oxygen atmosphere at a temperature of 750℃ for 8 hours to obtain the ternary cathode material.
[0074] Test case
[0075] The battery preparation method is as follows: The positive electrode material, polyvinylidene fluoride (PVDF), and acetylene black prepared in the examples and comparative examples are mixed with N-methylpyrrolidone (NMP) in a mass ratio of 96:2:2, wherein the mass ratio of solid to liquid is 7:3, to prepare a positive electrode slurry. The negative electrode material, graphite, binder LA133, and carbon nanotubes (CNTs) are mixed evenly in a mass ratio of 92:6:2 to prepare a mixed negative electrode slurry. The positive and negative electrode slurries are then processed through coating, rolling, slicing, winding, assembly, liquid injection, formation, secondary sealing, and capacity testing to prepare the finished soft-pack battery.
[0076] At 25°C, the battery is charged to 4.5V at a rate of 0.1C to obtain the initial charge specific capacity; then discharged to 3V at a rate of 0.1C to obtain the initial discharge specific capacity; the initial coulombic efficiency is the ratio of the initial charge specific capacity to the initial discharge specific capacity × 100%.
[0077] At 45℃, the battery is charged to 4.5V at a rate of 0.5C and then discharged to 3V at a rate of 0.5C for 500 cycles. The capacity retention rate in week X is calculated as (discharge specific capacity in week X / discharge specific capacity in week 1) × 100%, where X = 100, 200, 300, 400 or 500.
[0078] The specific test results are shown in Table 1.
[0079] Table 1
[0080] The composite phase ternary cathode material obtained in this application produces batteries with excellent specific capacity, coulombic efficiency, and cycle performance.
[0081] A comparison of the examples and the comparative examples shows that the electrical performance of the cathode material is improved after phase transition treatment.
[0082] A comparison of Example 1 and Example 7 shows that specific conditions for ion exchange can further optimize the effect, thereby further improving the electrical performance of the prepared cathode material.
[0083] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this application.
Claims
1. A method for preparing a composite phase ternary cathode material, the method comprising the following steps: S1, the ternary cathode material precursor is mixed with the first lithium source and sintered to obtain a sintered product; S2, the first calcined product, sodium source, and cobalt source are mixed and calcined to obtain the second calcined product; S3, the calcined product and the second lithium source are mixed and subjected to an ion exchange reaction to obtain a composite ternary cathode material.
2. The production method according to claim 1, wherein The ion exchange reaction is followed by mixing the ion exchange product with a coating agent, coating the product, and then sintering it.
3. The preparation method according to claim 2, wherein, The molar ratio of the total metal elements in the ternary cathode material precursor to the total metal elements in the coating agent is 1:(0.001-0.006).
4. The preparation method according to claim 2, wherein, The coating agent includes at least one of an aluminum source or a tungsten source; Optionally, the aluminum source includes at least one of aluminum oxide, aluminum hydroxide, or aluminum inorganic salt; more preferably, the aluminum source includes at least one of alumina, aluminum hydroxide, aluminum sulfate, aluminum chloride, or aluminum nitrate. Optionally, the tungsten source includes at least one of tungsten oxide, tungstic acid, or tungstate; more preferably, the tungsten source includes at least one of tungsten oxide, tungstic acid, or ammonium paratungstate. Optionally, when the coating agent is an aluminum source and a tungsten source, the molar ratio of aluminum in the aluminum source to tungsten in the tungsten source is (2-5):
1.
5. The preparation method according to any one of claims 1-4, wherein, The total amount of metal ions in the ternary cathode material precursor and the molar ratio of sodium in the sodium source to cobalt in the cobalt source are 1:(0.007-0.012):(0.01-0.015).
6. The preparation method according to any one of claims 1-5, wherein, The sodium source includes sodium-containing salts and / or sodium-containing bases; further optionally, the sodium source includes at least one of sodium carbonate, sodium bicarbonate, or sodium hydroxide. Optionally, the cobalt source includes at least one of cobalt oxide or cobalt hydroxide; more preferably, the cobalt source includes at least one of cobalt oxide, cobalt hydroxyoxide or cobalt hydroxide.
7. The preparation method according to any one of claims 1-6, wherein, The molar ratio of lithium in the second lithium source to sodium in the sodium source is 1-10:
1.
8. The preparation method according to any one of claims 1-7, wherein, The sintering conditions include: a sintering temperature of 900-1000℃ and a sintering time of 8-12h; Optionally, the calcination conditions include: a calcination temperature of 600-750℃ and a calcination time of 6-10h; Optionally, the conditions for the ion exchange reaction include: a temperature of 200-400℃ and a time of 1-8h. Optionally, the ion exchange reaction is carried out at a temperature of 250-380°C for a time of 2-6 hours.
9. A composite phase ternary cathode material prepared by the preparation method according to any one of claims 1-8.
10. A secondary battery comprising the composite phase ternary cathode material as described in claim 9.