Zr-modified high-nickel ncma positive electrode material, preparation method thereof, positive electrode sheet and battery
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SICHUAN EVERSEY TECHNOLOGY CO LTD
- Filing Date
- 2026-04-22
- Publication Date
- 2026-08-07
AI Technical Summary
然而，当镍含量较高时，材料在反复充放电过程中容易产生结构不稳定现象，例如：锂镍阳离子混排加剧；晶格结构发生变化；电极界面副反应增强
[0019]本发明的制备方法采用湿法混合与高温退火相结合的工艺路线，使锆源能够在NCMA颗粒表面实现均匀分布，并在热处理过程中形成稳定的结构调控作用。该方法工艺流程简单，反应条件易于控制，设备要求较低，同时具有操作方便、能耗适中以及可规模化实施等特点，适用于高镍层状氧化物正极材料的工业化制备。
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Figure CN122532183A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of battery materials technology, and in particular to Zr-modified high-nickel NCMA cathode materials, their preparation methods, cathode sheets, and batteries. Background Technology
[0002] With the development of electric vehicles and energy storage technologies, the requirements for energy density and cycle stability of lithium-ion batteries are constantly increasing. High-nickel layered oxide cathode materials have attracted widespread attention due to their high theoretical capacity. LiNi 0.89 Co 0.05 Mn 0.05 Al 0.01 O2 (NCMA) is a typical high-nickel ternary material. Introducing aluminum into the system can improve structural stability while maintaining high capacity. However, when the nickel content is high, the material is prone to structural instability during repeated charge-discharge cycles, such as increased lithium-nickel cation mixing, changes in crystal structure, and enhanced side reactions at the electrode interface. These problems lead to capacity decay and decreased cycle performance, thus limiting its practical applications.
[0003] To improve the stability of high-nickel materials, researchers have proposed various modification strategies, such as elemental doping and surface manipulation. Among these, introducing high-valence metal elements can stabilize the crystal structure and improve electrochemical performance to some extent. Therefore, developing a simple and effective modification method is of great significance. Summary of the Invention
[0004] In view of this, the purpose of this invention is to provide Zr-modified high-nickel NCMA cathode material and its preparation method, cathode sheet and battery, which achieve higher first reversible capacity and first coulombic efficiency, near-zero decay long-cycle stability, and excellent high-rate performance and rate reversibility.
[0005] The following is a summary of this disclosure to provide a basic understanding of some aspects. This summary is not intended to identify key or important elements, nor is it intended to limit the implementation or any aspects of the claims. Furthermore, this summary provides a simplified overview of some aspects that can be described in more detail in other parts of this disclosure.
[0006] The present invention solves the above-mentioned technical problems through the following technical means:
[0007] In a first aspect, embodiments of the present invention disclose a method for preparing a Zr-modified high-nickel NCMA cathode material, comprising the following steps:
[0008] High-nickel NCMA powder and zirconium source were added to anhydrous ethanol and mechanically ground to obtain a mixed powder.
[0009] The mixed powder was placed in an oxygen atmosphere, heated to 550–650°C and held for 3–6 hours, and then cooled to room temperature to obtain Zr-modified high-nickel NCMA cathode material.
[0010] In conjunction with the first aspect, in some embodiments, the mass ratio of the high-nickel NCMA powder to the zirconium source is 100:(0.5-3).
[0011] In conjunction with the first aspect, in some embodiments, the zirconium source is zirconium ethoxide, zirconium n-propoxide, zirconium oxychloride, nano-zirconium oxide, zirconium acetylacetone, or hydrated zirconium oxynitrate. In any of them, the x in the equation is a positive integer.
[0012] In conjunction with the first aspect, in some embodiments, the heating to 550-650°C and holding for 3-6 hours specifically means heating to 550-650°C at a rate of 3-8°C / min and holding for 3-6 hours.
[0013] In conjunction with the first aspect, in some embodiments, the cooling to room temperature is achieved by cooling to room temperature at a rate of 1 to 4 °C / min.
[0014] In conjunction with the first aspect, in some embodiments, the high-nickel NCMA powder is pretreated before the addition of anhydrous ethanol, wherein the pretreatment involves vacuum drying the high-nickel NCMA at 100–140°C for 4–8 hours.
[0015] In conjunction with the first aspect, in some embodiments, the pretreatment further includes placing the dried high-nickel NCMA in an oxygen atmosphere, heating it to 250–350°C and holding it there for 2–4 hours, and then cooling it to room temperature to obtain high-nickel NCMA powder.
[0016] Secondly, embodiments of the present invention also disclose a Zr-modified high-nickel NCMA cathode material, which is prepared by the preparation method described in the first aspect.
[0017] Thirdly, embodiments of the present invention also disclose a positive electrode sheet, wherein the raw materials for preparing the positive electrode sheet include the Zr-modified high-nickel NCMA positive electrode material described in the second aspect.
[0018] Fourthly, embodiments of the present invention also disclose a battery, the battery comprising the positive electrode sheet as described in claim 9.
[0019] The preparation method of this invention employs a process route combining wet mixing and high-temperature annealing, enabling the zirconium source to achieve uniform distribution on the surface of NCMA particles and forming a stable structural regulation effect during heat treatment. This method features a simple process flow, easily controllable reaction conditions, low equipment requirements, and is characterized by convenient operation, moderate energy consumption, and scalability, making it suitable for the industrial preparation of high-nickel layered oxide cathode materials.
[0020] The Zr-modified high-nickel NCMA cathode material of this invention introduces zirconium into the high-nickel NCMA material system and undergoes appropriate heat treatment, resulting in a modified cathode material with a complete crystal structure, uniform particle morphology, and stable structure. The introduction of zirconium effectively suppresses lattice distortion and transition metal migration in high-nickel materials during cycling, while improving interfacial stability, allowing the material to maintain a more stable structural framework during charge and discharge. Simultaneously, appropriate heat treatment conditions promote the rational distribution of zirconium on the material surface and in the lattice, thereby enhancing the stability of the crystal structure and reducing the probability of interfacial side reactions, enabling the electrode material to maintain good electrochemical performance under high voltage and long-cycle conditions. This invention provides an effective approach for the stabilization design of high-nickel layered cathode materials, which is of great significance for improving the energy density and cycle reliability of power battery systems.
[0021] After the electrode was prepared and the battery was assembled using the Zr-modified high-nickel NCMA cathode material of the present invention, the initial discharge capacity under 0.1C rate conditions reached 214.4 mAh / g, and the first-cycle coulombic efficiency was about 92.9%. When the cycle test was carried out under 1C rate conditions, the capacity retention rate still reached 98.4% after 100 charge-discharge cycles, indicating that the material has good performance in terms of cycle stability and rate performance. Attached Figure Description
[0022] Figure 1 The image shows the first charge-discharge cycle at 0.1C for a battery prepared using the Zr-modified high-nickel NCMA cathode material prepared in Example 1.
[0023] Figure 2 The image shows the first charge-discharge cycle at 0.1C for a battery prepared using the undoped Zr NCMA cathode material prepared in Comparative Example 1.
[0024] Figure 3 These are cycle performance graphs of batteries prepared using the cathode materials prepared in Example 1 and Comparative Example 1 at a 1C rate.
[0025] Figure 4 These are performance test graphs of batteries prepared using the cathode materials prepared in Example 1 and Comparative Example 1 under different rate conditions. Detailed Implementation
[0026] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.
[0027] 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 products.
[0028] To address the problems of lattice instability, enhanced interfacial reactions, and decreased cycle performance that easily occur in high-nickel layered cathode materials during repeated charge-discharge cycles, this invention proposes a Zr-modified high-nickel NCMA cathode material and its preparation method. This preparation method introduces an appropriate amount of Zr element into the high-nickel NCMA cathode material system to adjust the local lattice environment and material surface structure, thereby enhancing structural stability and improving cycle life.
[0029] The method for preparing the Zr-modified high-nickel NCMA cathode material of the present invention includes the following steps:
[0030] (1) According to the mass ratio of high-nickel NCMA powder to zirconium source of 100:(0.5~3), weigh out high-nickel NCMA powder and zirconium source respectively, add high-nickel NCMA powder and zirconium source to anhydrous ethanol, and use mechanical grinding to make each component uniformly dispersed and gradually evaporate the solvent to obtain a mixed powder with uniform component distribution. The zirconium source is zirconium ethoxide, zirconium n-propoxide, zirconium oxychloride, nano zirconium oxide, zirconium acetylacetone, and hydrated zirconium oxynitrate. In any of them, x in the equation is a positive integer.
[0031] (2) The mixed powder is transferred to a high-temperature resistant container and placed in a tube furnace with oxygen introduced for heat treatment. During the heating process, the temperature is increased to the target temperature of 550-650℃ at a rate of 3-8℃ / min and held for 3-6 hours to allow zirconium to react with NCMA material in a solid phase and achieve structural regulation. After the heat treatment is completed, the temperature is gradually reduced to room temperature at a rate of 1-4℃ / min to finally obtain Zr modified high-nickel NCMA cathode material.
[0032] In practical implementation, due to the presence of LiOH on the surface of high-nickel NCMA, Residual alkali has several drawbacks. First, it absorbs water, causing the zirconium source to hydrolyze and agglomerate on the surface, resulting in uneven coating. Second, the alkaline environment reacts with the zirconium source (especially alkoxides and zirconium acetylacetonate) to form flocculent precipitates. Third, the residual alkali layer hinders the bonding between Zr–O and the lattice oxygen of the material, resulting in weak adhesion and easy detachment during cycling. Therefore, the high-nickel NCMA used in this invention undergoes a two-step pretreatment process before the addition of anhydrous ethanol: drying to remove water and low-temperature pre-oxidation. Specifically, the high-nickel NCMA is vacuum-dried at 100–140°C for 4–8 hours to remove physically adsorbed water and prevent zirconium source hydrolysis. The dried high-nickel NCMA is then placed in an oxygen atmosphere, heated to 250–350°C, held for 2–4 hours, and then cooled to room temperature to obtain high-nickel NCMA powder. This gentle surface oxidation decomposes some of the residual alkali, repairs surface oxygen defects, and allows Zr to be directly "pinned" to the lattice.
[0033] The Zr-modified high-nickel NCMA cathode material and its preparation method of the present invention will be described below through specific embodiments:
[0034] Example 1
[0035] The preparation method of the Zr-modified high-nickel NCMA cathode material in this embodiment is as follows:
[0036] (1) High-nickel NCMA was vacuum dried at 120°C for 5 hours. The dried high-nickel NCMA was then placed in an oxygen atmosphere, heated to 300°C and kept at that temperature for 3 hours, and then cooled to room temperature to obtain high-nickel NCMA powder.
[0037] According to the mass ratio of high-nickel NCMA powder to zirconium source of 100:1, weigh out 1.00g of high-nickel NCMA powder and 0.01g of zirconium source. High-nickel NCMA powder and zirconium source were added together to 5 mL of anhydrous ethanol. The components were uniformly dispersed by mechanical grinding and the solvent was gradually evaporated until the system was transformed into a uniformly mixed dry powder, resulting in a mixed powder with uniform component distribution.
[0038] (2) The mixed powder was transferred to a high-temperature resistant container and placed in a tube furnace with oxygen introduced for heat treatment. During the heating process, the temperature was increased to the target temperature of 600℃ at a rate of 5℃ / min and held for 5h to allow zirconium to react with NCMA material in a solid phase and achieve structural regulation. After the heat treatment was completed, the temperature was gradually reduced to room temperature at a rate of 2℃ / min to finally obtain Zr modified high nickel NCMA cathode material.
[0039] Example 2
[0040] The preparation method of the Zr-modified high-nickel NCMA cathode material in this embodiment is as follows:
[0041] (1) High-nickel NCMA was vacuum dried at 100°C for 8 hours. The dried high-nickel NCMA was then placed in an oxygen atmosphere, heated to 250°C and kept at that temperature for 2 hours, and then cooled to room temperature to obtain high-nickel NCMA powder.
[0042] The mass ratio of high-nickel NCMA powder to zirconium source is 100:0.5. Weigh out 1.00g of high-nickel NCMA powder and 0.005g of zirconium source respectively. High-nickel NCMA powder and zirconium source were added together to 5 mL of anhydrous ethanol. The components were uniformly dispersed by mechanical grinding and the solvent was gradually evaporated until the system was transformed into a uniformly mixed dry powder, resulting in a mixed powder with uniform component distribution.
[0043] (2) The mixed powder was transferred to a high-temperature resistant container and placed in a tube furnace with oxygen introduced for heat treatment. During the heating process, the temperature was increased to the target temperature of 550℃ at a rate of 3℃ / min and held for 3h to allow zirconium to react with NCMA material in a solid phase and achieve structural regulation. After the heat treatment was completed, the temperature was gradually reduced to room temperature at a rate of 1℃ / min to finally obtain Zr modified high nickel NCMA cathode material.
[0044] Example 3
[0045] The preparation method of the Zr-modified high-nickel NCMA cathode material in this embodiment is as follows:
[0046] (1) High-nickel NCMA was vacuum dried at 140°C for 4 hours. The dried high-nickel NCMA was then placed in an oxygen atmosphere, heated to 350°C and kept at that temperature for 4 hours, and then cooled to room temperature to obtain high-nickel NCMA powder.
[0047] The mass ratio of high-nickel NCMA powder to zirconium source is 100:1. Weigh 1.00g of high-nickel NCMA powder and 0.01g of zirconium ethanol, and add the high-nickel NCMA powder and zirconium source together to 5mL of anhydrous ethanol. Use mechanical grinding to make the components uniformly dispersed and gradually evaporate the solvent until the system is transformed into a uniformly mixed dry powder, and a mixed powder with uniform component distribution is obtained.
[0048] (2) The mixed powder was transferred to a high-temperature resistant container and placed in a tube furnace with oxygen introduced for heat treatment. During the heating process, the temperature was increased to the target temperature of 580℃ at a rate of 5℃ / min and held for 5h to allow zirconium to react with NCMA material in a solid phase and achieve structural regulation. After the heat treatment was completed, the temperature was gradually reduced to room temperature at a rate of 2℃ / min to finally obtain Zr modified high nickel NCMA cathode material.
[0049] Example 4
[0050] The preparation method of the Zr-modified high-nickel NCMA cathode material in this embodiment is as follows:
[0051] (1) The mass ratio of high-nickel NCMA powder to zirconium source is 100:1. Weigh 1.00g of high-nickel NCMA powder and 0.01g of zirconium source respectively. High-nickel NCMA powder and zirconium source were added together to 5 mL of anhydrous ethanol. The components were uniformly dispersed by mechanical grinding and the solvent was gradually evaporated until the system was transformed into a uniformly mixed dry powder, resulting in a mixed powder with uniform component distribution.
[0052] (2) The mixed powder was transferred to a high-temperature resistant container and placed in a tube furnace with oxygen introduced for heat treatment. During the heating process, the temperature was increased to the target temperature of 630℃ at a rate of 5℃ / min and held for 5h to allow zirconium to react with NCMA material in a solid phase and achieve structural regulation. After the heat treatment was completed, the temperature was gradually reduced to room temperature at a rate of 2℃ / min to finally obtain Zr modified high nickel NCMA cathode material.
[0053] Example 5
[0054] The preparation method of the Zr-modified high-nickel NCMA cathode material in this embodiment is as follows:
[0055] (1) High-nickel NCMA was vacuum dried at 130°C for 5 hours. The dried high-nickel NCMA was then placed in an oxygen atmosphere, heated to 300°C and kept at that temperature for 3 hours, and then cooled to room temperature to obtain high-nickel NCMA powder.
[0056] The mass ratio of high-nickel NCMA powder to zirconium source is 100:3. Weigh 1.00g of high-nickel NCMA powder and 0.03g of zirconium propoxide, and add the high-nickel NCMA powder and zirconium source together to 6mL of anhydrous ethanol. Use mechanical grinding to make the components uniformly dispersed and gradually evaporate the solvent until the system is transformed into a uniformly mixed dry powder, and a mixed powder with uniform component distribution is obtained.
[0057] (2) The mixed powder was transferred to a high-temperature resistant container and placed in a tube furnace with oxygen introduced for heat treatment. During the heating process, the temperature was increased to the target temperature of 650°C at a rate of 8°C / min and held for 6 hours to allow zirconium to react with NCMA material in a solid phase and achieve structural regulation. After the heat treatment was completed, the temperature was gradually reduced to room temperature at a rate of 4°C / min to finally obtain Zr modified high-nickel NCMA cathode material.
[0058] Comparative Example 1
[0059] Weigh 1.00 g of NCMA powder as the original cathode material. Without adding any zirconium source, add the powder to 5 mL of anhydrous ethanol and grind it to disperse it evenly and evaporate the solvent, thereby obtaining a dry powder.
[0060] The powder was then transferred to an alumina crucible and placed in a tube furnace for heat treatment. Oxygen was introduced into the furnace as a reaction atmosphere, and the temperature was raised to 600 °C at a heating rate of 5 °C / min. The temperature was maintained at this temperature for 5 hours. After the heat treatment, the temperature was lowered to room temperature at a rate of 2.5 °C / min to obtain undoped zirconium NCMA material.
[0061] The Zr-modified high-nickel NCMA cathode material prepared in Example 1 and the undoped zirconium NCMA material prepared in Comparative Example 1 were used as cathode material samples for specific capacity and cycle performance testing. Specifically, cathode material samples, carbon black (SP), and polyvinylidene fluoride (PVDF) were weighed and mixed in a mass ratio of 90:5:5 to prepare cathode slurry. PVDF was a 3.5 wt% solution prepared using N-methylpyrrolidone (NMP) as a solvent. The slurry was uniformly coated onto aluminum foil (area density 2.2 mg / cm²). 2 After drying in a 120 ℃ drying oven for 10 hours, the material was sliced to a diameter of 12 mm and weighed to obtain the NCM positive electrode for lithium-ion batteries. Using lithium metal sheets as the negative electrode and a mixed solution of ethylene carbonate (EC) and diethyl carbonate (DEC) of 1 mol / L LiPF6 (volume ratio 1:1) as the electrolyte, CR2025 button batteries were assembled in an argon-atmospheric glove box. Finally, the batteries were placed in the Xinwei testing system for electrical performance testing.
[0062] The electrical performance test parameters were set as follows: voltage range 2.7V~4.3V; specific capacity was tested at 0.1C charge / 0.1C discharge for the first cycle; 100 cycles (cycles 3 to 102) were performed at 1C charge / 1C discharge to test its cycle performance; rate performance was tested at 0.1C, 0.2C, 0.5C, 1C, 2C, and 5C rates. The test results are as follows. Figure 1-4 As shown.
[0063] Figure 1 and Figure 2 The data shows that, on the one hand, the initial discharge specific capacity of Example 1 is improved compared to Comparative Example 1. This indicates that Zr modification did not sacrifice the specific capacity of high-nickel materials; on the contrary, it slightly improved the utilization rate of active materials. The core reason is that Zr doping suppressed... Migration to the Li site reduces the degree of cation mixing and decreases... Lattice site traps for insertion and extraction broaden the range of intercalation and extraction. Transmission channels allow more Reversible insertion / extraction is achieved. On the other hand, the first-cycle coulombic efficiency of Example 1 is improved by 4.7% compared to Comparative Example 1. A secondary heat treatment is performed under oxygen conditions. It forms strong bonds with lattice oxygen, reduces oxygen vacancies in the material, suppresses oxygen evolution side reactions during the first charge and discharge process, and further reduces irreversible capacity loss.
[0064] Figure 3 The data shows that after 100 cycles, the capacity retention rate of Example 1 was 98.4%, which was much higher than that of Comparative Example 1 (89.6%), and the specific capacity throughout the discharge was always higher than that of Comparative Example 1, proving that Zr modification effectively suppressed the capacity decay of high-nickel NCMA.
[0065] Figure 4 The data shows that as the multiplier increases, the difference between Example 1 and Comparative Example 1 continues to widen, with the advantage being particularly prominent at high multipliers: at a 2C multiplier, the specific capacity of Example 1 is approximately higher than that of Comparative Example 1. At a 5C magnification rate, Example 1 can still maintain... The specific capacity, while Comparative Example 1 only The gap exceeds .
[0066] In summary, the Zr-modified high-nickel NCMA cathode material of this invention simultaneously achieves: higher initial reversible capacity and initial coulombic efficiency, near-zero decay long-cycle stability, and excellent high-rate performance and rate reversibility. It fundamentally solves the core problems of high-nickel ternary materials, such as interfacial instability, structural collapse, and poor cycle / rate performance. Therefore, the Zr-modified high-nickel NCMA cathode material of this invention can be assembled into lithium-ion battery systems as a cathode active material, thereby constructing electrochemical energy storage devices with excellent cycle and rate performance.
[0067] The foregoing description includes examples from this specification. Of course, for the purposes of describing this specification, it is impossible to describe every conceivable combination of components or methods; however, those skilled in the art will understand that many other combinations and arrangements are possible. Therefore, this specification is intended to cover all such changes, modifications, and variations that fall within the spirit and scope of the appended claims. Furthermore, with regard to the use of the term "comprising" in the detailed description or claims, the term is intended to be inclusive in a manner similar to the term "including," as interpreted when "comprising" is used as a transitional word in the claims.
[0068] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.
Claims
1. A method for preparing Zr-modified high-nickel NCMA cathode material, characterized in that, Includes the following steps: High-nickel NCMA powder and zirconium source were added to anhydrous ethanol and mechanically ground to obtain a mixed powder. The mixed powder was placed in an oxygen atmosphere, heated to 550–650°C and held for 3–6 hours, and then cooled to room temperature to obtain Zr-modified high-nickel NCMA cathode material.
2. The preparation method according to claim 1, characterized in that, The mass ratio of the high-nickel NCMA powder to the zirconium source is 100:(0.5-3).
3. The preparation method according to claim 1, characterized in that, The zirconium source is zirconium ethoxide, zirconium n-propoxide, zirconium oxychloride, nano-zirconium oxide, zirconium acetylacetone, or hydrated zirconium oxynitrate. In any of them, the x in the equation is a positive integer.
4. The preparation method according to claim 1, characterized in that, The process of heating to 550-650℃ and holding for 3-6 hours specifically involves heating to 550-650℃ at a rate of 3-8℃ / min and holding for 3-6 hours.
5. The preparation method according to claim 1, characterized in that, The cooling to room temperature refers to cooling to room temperature at a rate of 1 to 4 °C / min.
6. The preparation method according to claim 1, characterized in that, The high-nickel NCMA powder was pretreated before the addition of anhydrous ethanol. The pretreatment involved vacuum drying the high-nickel NCMA at 100–140°C for 4–8 hours.
7. The preparation method according to claim 6, characterized in that, The pretreatment also includes placing the dried high-nickel NCMA in an oxygen atmosphere, heating it to 250-350°C and holding it there for 2-4 hours, and then cooling it to room temperature to obtain high-nickel NCMA powder.
8. A Zr-modified high-nickel NCMA cathode material, characterized in that, The Zr-modified high-nickel NCMA cathode material is prepared using the preparation method described in any one of claims 1-7.
9. A positive electrode sheet, characterized in that, The raw materials for preparing the positive electrode include the Zr-modified high-nickel NCMA positive electrode material as described in claim 8.
10. A battery, characterized in that, The battery includes the positive electrode as described in claim 9.