Positive electrode material, preparation method thereof, battery and electric device

Abstract

The application relates to the technical field of batteries, in particular to a positive electrode material and a preparation method thereof, a battery and an electric device, the positive electrode material comprising a compound shown in formula 1: Li 1+a (Ni x Co y Mn z Ti b )M c O 2±d The positive electrode material shown in formula 1 satisfies: 0 < S k < 1; 2 < K < 4; 1.60 <= B = D 50 / mu <= 2.45; wherein, S k is a skewness coefficient of a grain size sample of the positive electrode material obtained by using a 3rd moment method, K is a kurtosis coefficient of the grain size sample of the positive electrode material obtained by using a 4th moment method, B is an average grain number of the positive electrode material, D 50 is a median particle size of the positive electrode material, and mu is an average grain size of the positive electrode material. The positive electrode material has a narrow grain size distribution curve, uniform size, good particle independence and good cycle performance at a high voltage.

Description

Technical Field

[0001] This application belongs to the field of battery technology, specifically relating to cathode materials and their preparation methods, batteries, and electrical devices. Background Technology

[0002] The rapid development of the electric vehicle industry has increased demands for battery performance in terms of lifespan, energy density, cycle performance, cost, and environmental friendliness. The performance of the cathode material directly affects the key performance indicators of lithium-ion batteries. In related technologies, single-crystal cathode materials are typically prepared using solid-state reactions. This method has the advantages of simple processing and ease of large-scale production. However, cathode materials prepared using this method still exhibit problems in practical applications, such as poor capacity retention during high-voltage cycling and even cycle-limiting degradation. Therefore, cathode material technologies still require improvement. Summary of the Invention

[0003] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, this invention proposes a high-capacity cathode material with good high-voltage cycle performance, its preparation method, a battery, and an electrical device thereof.

[0004] In a first aspect, this application provides a cathode material. According to embodiments of this application, the cathode material comprises a compound shown in Formula 1: Li 1+a (Ni x Co y Mn z Ti b M c O 2±d Formula 1 In Equation 1, 0.05≤a≤0.2, 0.5≤x<1, 0.5≤y<1, 0.5≤z<1, 0≤b<0.01, 0 <c<0.05,0≤d<0.1; The element M includes at least one of B, Mg, Al, Si, P, Co, Sr, Y, Zr, Sb, W, La, and Ce; The cathode material satisfies: 0 k <1; 2 <K<4; 1.60≤B= D 50 / μ≤2.45; Among them, S k The skewness coefficient of the grain size sample of the cathode material is obtained using the third-order moment of motion method, K is the kurtosis coefficient of the grain size sample of the cathode material obtained using the fourth-order moment of motion method, B is the average number of grains of the cathode material, and D is the skewness coefficient of the grain size sample of the cathode material. 50 ​denoted as the median particle size of the cathode material, and μ as the average grain size of the cathode material.

[0005] The cathode material that satisfies the aforementioned skewness and kurtosis coefficients can produce cathode materials with fewer small particles and more concentrated grain size. This narrows the grain size distribution curve, reduces the proportion of micronized powder in the cathode material, and improves the uniformity of grain size. Satisfying the aforementioned average grain number can reduce the degree of adhesion between particles and improve the independence of grains. In synergy with the skewness and kurtosis coefficients, the uniformity of grain size can be further improved, thereby increasing the compaction density of the cathode material. This effectively mitigates the occurrence of side reactions between the cathode material and the electrolyte under high voltage or long cycle time, extends battery life, and yields cathode materials with high capacity and good cycle performance under high voltage.

[0006] According to embodiments of this application, the cathode material satisfies at least one of the following conditions: 0 k <0.4; 2.5 <K<3.5; 1.88≤B= D 50 / μ≤2.00; 0 <b<0.01。

[0007] According to the embodiments of this application, 1.0μm < μ < 3.0μm, preferably 1.4μm < μ < 2.2μm.

[0008] According to embodiments of this application, the cathode material satisfies: 1.28 ≤ B × K 90 ≤3.07, preferably 1.88≤B×K 90 ≤2.20, where K 90 K represents the particle size distribution of the cathode material. 90 =(D 90 -D 10 ) / D 50 .

[0009] According to an embodiment of this application, the particle size distribution K of the positive electrode material is... 90 Satisfy: 0.80≤K 90 ≤1.25, preferably 1.00≤K 90 ≤1.10.

[0010] According to an embodiment of this application, the ellipticity P of the cathode material satisfies: 0≤P<0.8, preferably 0≤P<0.4, wherein the ellipticity P is the ratio of the difference between the length of the longest and shortest diagonal of the cross-section of the cathode material particles to its grain size.

[0011] ​According to embodiments of this application, the grain size distribution curve of the cathode material includes two peaks and satisfies at least one of the following conditions: The distance between the two peaks is less than 0.6 μm; The proportion of small particle peaks in the two peaks is higher than that of large particle peaks.

[0012] In a second aspect, this application provides a method for preparing the aforementioned cathode material. According to an embodiment of this application, the method includes: mixing a nickel-cobalt-manganese precursor with a first lithium source and optionally a titanium-containing compound to obtain a first mixture; subjecting the first mixture to a first sintering and first crushing the resulting first sintered product to a first processed product; mixing the first processed product, a second lithium source, and optionally the titanium-containing compound to obtain a second mixture; subjecting the second mixture to a second sintering and second crushing the resulting second sintered product to a second processed product; mixing the second processed product with a compound containing M to obtain a third mixture; and subjecting the third mixture to a third sintering to obtain the cathode material; wherein the ratio of the sum of the amounts of nickel, cobalt, and manganese elements in the nickel-cobalt-manganese precursor, the amount of lithium element in the first lithium source, and the amount of lithium element in the second lithium source is 1:0.2~0.8:0.25~0.85; and the M element is at least one selected from B, Mg, Al, Si, P, Ti, Co, Sr, Y, Zr, Sb, La, and Ce. This method improves the homogeneity of the material reaction process through lithium-deficient sintering, resulting in a more rounded and regular morphology and uniform grain size in the prepared cathode material, which has better cycle performance.

[0013] According to embodiments of this application, the first sintering satisfies at least one of the following conditions: The heating time for the first sintering is 2h to 10h, preferably 6h to 8h; The temperature of the first sintering is 600℃~1100℃, preferably 700℃~900℃; The holding time for the first sintering is 6h to 12h, preferably 8h to 10h.

[0014] According to an embodiment of this application, the second sintering satisfies at least one of the following conditions: The heating time for the second sintering is 2h to 10h, preferably 6h to 8h; The temperature of the second sintering is 800℃~1100℃, preferably 900℃~1000℃; The holding time for the second sintering is 6h~12h, preferably 8h~10h.

[0015] According to an embodiment of this application, the third sintering satisfies at least one of the following conditions: The heating time for the third sintering is 2h to 10h, preferably 3h to 8h; The temperature of the third sintering is 300℃~900℃, preferably 400℃~800℃; The holding time for the third sintering is 6h to 12h, preferably 8h to 10h.

[0016] According to embodiments of this application, the method satisfies at least one of the following conditions: The nickel-cobalt-manganese precursor includes at least one of nickel-cobalt-manganese hydroxide and nickel-cobalt-manganese oxide; The first lithium source and the second lithium source each independently include at least one of lithium carbonate, lithium hydroxide, lithium acetate, and lithium chloride; The titanium-containing compound includes at least one of titanium oxides, hydroxides, carbonates, and phosphates; The M-containing compound includes at least one of the following: oxides, hydroxides, carbonates, and phosphates of element M.

[0017] A third aspect of this application discloses a battery comprising the positive electrode material described in the first aspect of this application or the positive electrode material prepared by the method of the second aspect. Therefore, this battery has high energy density and excellent cycle performance under high voltage.

[0018] A fourth aspect of this application discloses an electrical device comprising the positive electrode material described in the first aspect, the positive electrode material prepared by the method of the second aspect, or the battery described in the third aspect. This electrical device possesses all the features and advantages of the batteries described above, which will not be repeated here.

[0019] This application has at least the following beneficial effects: (1) Positive electrode materials with micro-positive skew distribution characteristics have uniform particle size and better performance in cycle life and processability under high working voltage.

[0020] (2) Using a small amount of Ti doping to suppress the growth of large particles results in a relatively concentrated grain size distribution and a sharp grain size distribution curve.

[0021] (3) The lithium-depleted sintering process can improve the homogeneity of the material reaction process, and the prepared cathode material has a more rounded and regular morphology and uniform grain size, resulting in better cycle performance.

[0022] (4) By adjusting the crushing intensity to reduce the average number of particles, the independence of particles can be improved, thereby increasing the cycle life. Attached Figure Description

[0023] Figure 1 This is a SEM image of the cathode material in Embodiment 1 of this application.

[0024] Figure 2 This is a grain size distribution diagram of the cathode material in Embodiment 1, Embodiment 2, and Comparative Example 1 of this application. Detailed Implementation

[0025] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0026] This application is based on the inventor's discoveries and understanding of the following facts and problems: Currently, solid-state reaction processes are the main method for preparing cathode materials due to their simplicity and ease of large-scale production. However, the prepared cathode materials suffer from problems such as difficulty in controlling the uniformity of grain size and shape, irregular particle morphology, poor roundness, severe adhesion of small particles, and excessively high proportion of micronized powder. Electrodes made from these cathode materials are prone to particle breakage after rolling, which exacerbates the occurrence of electrolyte side reactions, leading to poor capacity retention and even cycle failure during high-voltage cycling. Based on the above, the inventors of this application propose a cathode material that can finely control the grain size distribution of the cathode material, obtaining a cathode material with good grain independence, uniform size, regular morphology, and excellent cycle performance under high voltage.

[0027] In view of the above, in a first aspect, this application provides a cathode material. According to embodiments of this application, the cathode material comprises a compound shown in Formula 1: Li 1+a (Ni x Co y Mn z Ti b M c O 2±d Formula 1 In Equation 1, 0.05≤a≤0.2, 0.5≤x<1, 0.5≤y<1, 0.5≤z<1, 0≤b<0.01, 0 <c<0.05,0≤d<0.1; The element M includes at least one of B, Mg, Al, Si, P, Co, Sr, Y, Zr, Sb, W, La, and Ce; The cathode material satisfies: 0 k <1; 2 <K<4; 1.60≤B= D 50 / μ≤2.45.

[0028] ​The cathode material that satisfies the aforementioned skewness and kurtosis coefficients can produce cathode materials with fewer small particles and more concentrated grain size. This narrows the grain size distribution curve, reduces the proportion of micronized powder in the cathode material, and improves the uniformity of grain size. Satisfying the aforementioned average grain number can reduce the degree of adhesion between particles and improve the independence of grains. In synergy with the skewness and kurtosis coefficients, the uniformity of grain size can be further improved, thereby increasing the compaction density of the cathode material. This effectively mitigates the occurrence of side reactions between the cathode material and the electrolyte under high voltage or long cycle time, extends battery life, and yields cathode materials with high capacity and good cycle performance under high voltage.

[0029] In this paper, grain size is used to measure the size of cathode material particles, which can be obtained by calculating the average of the longest and shortest diagonals of the cathode material particles.

[0030] In this article, S k The skewness coefficient of the cathode material's grain size sample is obtained using the third-order method of moments. The method of moments is a data analysis and processing method based on the concept of moments (moments) in statistics and probability theory. It has wide applications in statistics, primarily used to describe the characteristics of data distribution. The skewness coefficient (or skewness coefficient) S of the cathode material's grain size is calculated using this method. k Skewness coefficient S can be used as a characteristic number to measure the deviation of grain size distribution from a normal distribution, and is used to measure the uniformity of grain size in cathode materials. k The symmetry of the data distribution is measured using the third central moment. The formula for the skewness coefficient is: Skewness coefficient S k =E[(X μ) 3 ] / σ 3 ; where E[(X μ) 3 [ ] is the third central moment, X is the grain size of each particle, μ is the average value, and σ is the standard deviation. Skewness coefficient S k A value of 0 indicates a symmetrical distribution; the skewness coefficient S k A value greater than 0 indicates positive skewness; the skewness coefficient S k A value less than 0 indicates a negatively skewed state.

[0031] In this article, the grain size sample of cathode materials refers to all the statistically analyzed grain size values ​​of the cathode materials, that is, all the grain size values ​​statistically analyzed in the grain size distribution curve of the cathode materials. As an example, the grain size distribution curve is plotted by statistically analyzing the grain size of 500 cathode material particles, and the grain size values ​​of these 500 cathode material particles are the grain size sample of the cathode materials.

[0032] According to an embodiment of this application, 0 k ​<1. In some embodiments, 0 < S k <0.4. As an example, S k can specifically be 0.01, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 0.99, etc. In the present application, by controlling the skewness coefficient of the positive electrode material to satisfy the above range, the grain size uniformity of the positive electrode material is better, the proportion of fine powder is lower, and the particle size is more concentrated. Furthermore, side reactions can be further reduced and the cycle life under high voltage can be improved.

[0033] In this article, K is the kurtosis coefficient of the grain size sample of the positive electrode material obtained by the fourth-order moment method. Calculating the kurtosis coefficient of the grain size of the positive electrode material by the moment method as a characteristic number to measure the deviation of the grain size distribution from the normal distribution can be used to measure the sharpness of the grain size distribution curve of the positive electrode material. The formula for the kurtosis coefficient (or kurtosis coefficient) K is: Kurtosis coefficient = E[(X μ) 4 / σ 4 , where E[(X μ) 4 is the fourth-order central moment, X is the grain size of a single particle, μ is the average value, and σ is the standard deviation. A kurtosis coefficient of 3 indicates a normal peak distribution; greater than 3 indicates a sharp peak; less than 3 indicates a flat peak.

[0034] According to the embodiments of the present application, 2 < K < 4. In some embodiments, 2.5 < K < 3.5. As an example, K can specifically be 2.01, 2.2, 2.4, 2.6, 2.8, 3.0, 3.2, 3.4, 3.6, 3.8, 3.99, etc. In the present application, by controlling the kurtosis coefficient of the positive electrode material to satisfy the above range, the grain size uniformity of the positive electrode material is better, the proportion of fine powder is lower, and the particle size is more concentrated. Furthermore, side reactions can be further reduced and the cycle life under high voltage can be improved.

[0035] In this article, B is the average grain number of the positive electrode material, D 50 is the median particle size of the positive electrode material, and μ is the average grain size of the positive electrode material. Among them, the particle size of the positive electrode material is tested by a Malvern particle size analyzer, and the particle size value of the 50% particle arranged from small to large according to the volume distribution is defined as D 50 . The grain size of the finished positive electrode material in the SEM is tested by any grain size mapping software, and μ is the arithmetic mean result obtained by taking 400 particles as samples.

[0036] According to the embodiments of the present application, 1.60 ≤ B = D 50 / μ ≤ 2.45. In some embodiments, 1.88 ≤ B = D 50 / μ≤2.00. For example, B can specifically be 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.45, etc. B is the average number of grains in the cathode material, used to measure the independence of the cathode material particles. The larger the average number of grains, the more adhesion between particles, and the worse the independence. If B meets the above range, it indicates that the cathode material has less adhesion and better particle independence. Combined with the aforementioned skewness and kurtosis coefficients, this results in good uniformity of cathode material grain size, a low proportion of micronized powder, high particle size concentration, and good particle independence, thereby significantly improving energy density and cycle performance under high voltage.

[0037] According to an embodiment of this application, the following condition is met: 1.28 ≤ B × K 90 ≤3.07, specifically, 1.88≤B×K 90 ≤2.20. As an example, B×K 90 Specifically, the values ​​can be 1.28, 1.5, 1.8, 2.0, 2.2, 2.4, 2.6, 2.8, 3.0, 3.07, etc. The composite parameter is B×K. 90 To evaluate the overall quality of the microstructure of cathode materials, a key parameter K, characterizing the dispersion of particle size distribution, is coupled through a mathematical product. 90 B, a key parameter characterizing the particle independence of cathode materials, quantitatively reflects the uniformity and regularity of the overall structure of the cathode material. B×K 90 The numerical value directly reflects the overall state of the cathode material particle cluster in terms of both "size uniformity" and "morphological independence." This application will use B×K... 90 By precisely controlling the structure within the aforementioned range, optimal structural synergy can be achieved, resulting in cathode materials with both a sufficiently narrow particle size distribution and highly independent cathode material particles. This state significantly shortens and regularizes the diffusion path of lithium ions within the cathode material, while minimizing structural defects (such as microcracks and localized stress) and side reaction interfaces caused by excessive grain boundaries or large particle size differences. This greatly improves the structural stability of the electrode, reduces ion transport impedance, and thus endows the battery with excellent rate performance, high energy density, and significantly extended cycle life.

[0038] In this article, K 90 K represents the particle size distribution of the cathode material. 90 =(D 90 -D 10 ) / D 50 The particle size of the cathode material was measured using a Malvern particle size analyzer. The particle sizes of the 10th, 50th, and 90th percentiles of the particles arranged in ascending order of volume distribution were defined as D. 10 D 50 and D 90 .

[0039] According to an embodiment of this application, the particle size distribution K of the positive electrode material is... 90 Satisfy: 0.80≤K 90 ≤1.25, specifically, 1.00≤K 90 ≤1.10. As an example, K 90 Specifically, the values ​​can be 0.8, 0.9, 1.0, 1.1, 1.2, 1.25, etc. Meeting these ranges ensures that the cathode material has a sufficiently narrow particle size distribution, which is beneficial for improving the compaction density and structural stability of the particles, thereby increasing the energy density and cycle life of the battery at high voltage.

[0040] According to embodiments of this application, the grain size μ of the cathode material satisfies: 1.0 μm < μ < 3.0 μm, specifically, 1.4 μm < μ < 2.2 μm. As an example, μ can specifically be 1.0, 1.2, 1.4, 1.6, 1.8, 2.0, 2.2, 2.4, 2.6, 2.8, 3.0, etc. By satisfying the above average grain size, the cathode material has a higher compaction density and a higher grain size concentration, thereby helping to reduce side reactions between the cathode material and the electrolyte and improve its cycle life under high voltage.

[0041] According to an embodiment of this application, the ellipticity P of the cathode material satisfies: 0 ≤ P < 0.8, specifically, 0 ≤ P < 0.4. As an example, p can specifically be 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.79, etc. Satisfying the above range indicates that the particle morphology of the cathode material is suitable, which is more conducive to stress dispersion during rolling, less prone to breakage, and more conducive to dense packing, increasing compaction density, thereby improving the energy density and cycle life of the battery.

[0042] Specifically, SEM reveals that the cross-section of cathode material particles is approximately circular. Therefore, ellipticity is introduced to describe the degree to which the cross-section of cathode material particles deviates from a circular shape. Ellipticity P is the ratio of the difference between the longest and shortest diagonal lengths of the cross-section of the cathode material particle to its grain size, i.e., P = (longest diagonal - shortest diagonal) / grain size. The closer the ellipticity is to 0, the better the roundness of the particles. Ellipticity can be measured and calculated using arbitrary grain size mapping software or SEM image mapping software.

[0043] According to an embodiment of this application, the grain size distribution curve of the cathode material includes two peaks. Therefore, the cathode material with this characteristic exhibits high grain size uniformity and grain size concentration, which is beneficial for improving the capacity and cycle life of the cathode material.

[0044] According to an embodiment of the present application, the grain size distribution curve of the positive electrode material includes two peaks, and the spacing between the two peaks is less than 0.6 μm, specifically such as 0.59 μm, 0.5 μm, 0.4 μm, 0.3 μm, 0.2 μm, 0.1 μm, etc. Meeting the above requirements enables the positive electrode material to have a right-skewed distribution characteristic while the grain size is relatively uniform, and thus has a higher tap density and better high-voltage cycling performance.

[0045] According to an embodiment of the present application, the grain size distribution curve of the positive electrode material includes two peaks, and the proportion of the small particle peak in the two peaks is higher than that of the large particle peak. Meeting the above requirements enables the positive electrode material to have a right-skewed distribution characteristic while the grain size is relatively uniform, and thus has a higher tap density and better high-voltage cycling performance.

[0046] In this article, the small particle peak refers to the peak with a smaller grain size corresponding to the peak value, and the large particle peak refers to the peak with a larger grain size corresponding to the peak value, that is, the grain size corresponding to the peak value of the small particle peak is smaller than the grain size corresponding to the peak value of the large particle peak; in other words, in the grain size distribution curve of the positive electrode material, the small particle peak is located on the left side of the large particle peak.

[0047] According to an embodiment of the present application, each component in Formula 1 can also be appropriately adjusted according to actual needs. In some embodiments, a can specifically be -0.05, 0.08, 0.1, 0.12, 0.15, 0.18, 0.2, etc.; x can specifically be 0.5, 0.6, 0.7, 0.8, 0.9, 0.99, etc.; y can specifically be 0.5, 0.6, 0.7, 0.8, 0.9, 0.99, etc.; z can specifically be 0.5, 0.6, 0.7, 0.8, 0.9, 0.99, etc.; c can specifically be 0.001, 0.01, 0.02, 0.03, 0.04, 0.049, etc.; d can specifically be 0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.099, etc. Thus, the comprehensive performance of the positive electrode material can be further improved.

[0048] According to an embodiment of the present application, by introducing Ti element with the effect of refining grains, the grain morphology and grain size distribution of the positive electrode material can be reasonably regulated. In some embodiments, 0 < b < 0.01. As an example, b can specifically be 0.001, 0.002, 0.003, 0.004, 0.005, 0.006, 0.007, 0.008, 0.009, 0.099, etc. Within the above content range, the Ti element can better play the role of refining grains, thereby obtaining a positive electrode material with better grain size uniformity, higher grain size concentration, and better particle independence.

[0049] According to embodiments of this application, the cathode material comprises a single-crystal cathode material. This further improves the high-voltage cycling performance of the cathode material.

[0050] According to embodiments of this application, the positive electrode material may include a core and a coating layer covering at least a portion of the outer surface of the core. In some embodiments, the core is Li. 1+a (Ni x Co y Mn z Ti b )O 2±d Ti is mainly doped in the core lattice, while M is mainly found in the coating layer.

[0051] A second aspect of this application provides a method for preparing the aforementioned cathode material. According to embodiments of this application, the method includes the following steps: S10: Mix the nickel-cobalt-manganese precursor with a first lithium source and optionally a titanium-containing compound to obtain a first mixture.

[0052] According to embodiments of this application, the specific type of nickel-cobalt-manganese precursor is not particularly limited and can be selected according to actual needs. In some embodiments, the nickel-cobalt-manganese precursor includes at least one of nickel-cobalt-manganese hydroxide and nickel-cobalt-manganese oxide. Therefore, the material is widely available and the cost is low.

[0053] According to embodiments of this application, the specific type of the first lithium source is not particularly limited and can be selected according to actual needs. In some embodiments, the first lithium source includes at least one of lithium hydroxide, lithium carbonate, lithium acetate, and lithium chloride. Therefore, the source is wide-ranging, the raw material quality is high, and the cost is low.

[0054] According to embodiments of this application, in this step, the addition of a titanium-containing compound can be selected based on actual usage needs. Specifically, the nickel-cobalt-manganese precursor and the first lithium source can be directly mixed to obtain a first mixture; alternatively, the nickel-cobalt-manganese precursor, the first lithium source, and the titanium-containing compound can be mixed to obtain the first mixture. In some embodiments, the titanium-containing compound includes at least one of titanium oxides, hydroxides, carbonates, and phosphates. This effectively refines the grain size, promoting the acquisition of cathode materials with good grain size uniformity and high concentration, thereby improving the capacity and cycle performance of the cathode material.

[0055] According to the embodiments of this application, the sum of the amounts of nickel, cobalt, and manganese elements in the nickel-cobalt-manganese precursor and the amount of lithium elements in the first lithium source are in the ratio of 1:0.2 to 0.8, specifically 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, etc.

[0056] Specifically, the solid-state reaction process between the nickel-cobalt-manganese precursor and the lithium source can be divided into two stages: a low-temperature nucleation stage where the raw material undergoes initial lithiation through melting and lithium formation, and a high-temperature growth stage where the lithium salt reacts fully with the crystal nuclei. During this process, factors such as uneven mixing of the lithium source and limited reaction time can cause the cathode material growth to deviate from the ideal Oswald ripening process, leading to uneven grain size and even bimodal distribution. This application controls the ratio of the nickel-cobalt-manganese precursor to the first lithium source within the aforementioned range, employing a lithium-depleted sintering method to precisely control the synthesis process. The mixture of the nickel-cobalt-manganese precursor and the first lithium source (50% ≤ theoretical lithium salt addition < 100%) is sintered once at a reaction temperature lower than that used for grain growth. This directionally lithiates high-density low-activation-energy sites and sparse high-activation-energy sites on the precursor surface under lithium-depleted conditions, effectively limiting the bimodal proportion of the subsequent finished grain size.

[0057] According to embodiments of this application, there are no particular limitations on the specific method of mixing the nickel-cobalt-manganese precursor with the first lithium source and optionally a titanium-containing compound; for example, a high-speed mixer or a soymilk maker can be used for mixing. This results in more uniform mixing, which is beneficial for obtaining a cathode material with better uniformity.

[0058] S20: The first mixture is sintered for the first time and the resulting sintered product is crushed for the first time to obtain the first process product.

[0059] According to embodiments of this application, the heating time for the first sintering is 2 hours to 10 hours, specifically 6 hours to 8 hours. As examples, the heating time for the first sintering can be 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, or 10 hours. Within this range, the raw materials can be heated uniformly, avoiding problems such as localized overheating.

[0060] According to an embodiment of this application, the temperature of the first sintering is 600℃~1100℃, specifically 700℃~900℃. As an example, the temperature of the first sintering can specifically be 600℃, 700℃, 800℃, 900℃, 1000℃, 1100℃, etc. Within the above temperature range, it is suitable for the directional lithiation of high-density low-activation-energy sites and sparse high-activation-energy sites on the surface of the precursor in a lithium-poor environment, effectively limiting the bimodal proportion of the subsequent finished product grain size.

[0061] According to embodiments of this application, the holding time for the first sintering is 6h to 12h, specifically 8h to 10h. As an example, the holding time for the first sintering can be 6h, 7h, 8h, 9h, 10h, 11h, 12h, etc. Within the above range, the high-density low-activation-energy sites and sparse high-activation-energy sites on the precursor surface can be fully lithiated without wasting time.

[0062] According to embodiments of this application, the first crushing process can dissociate the product from the first sintering, reducing the adhesion of the cathode material and improving the particle independence of the cathode material. In some embodiments, the equipment used for the first crushing process can be one or more of a soybean milk maker, rotary mill, double roller mill, colloid mill, mechanical mill, and air jet mill.

[0063] S30: The first process product, the second lithium source, and optionally the titanium-containing compound are mixed to obtain a second mixture.

[0064] According to embodiments of this application, in this step, the addition of a titanium-containing compound can be selected based on actual usage needs. Specifically, the first process product and the second lithium source can be directly mixed to obtain a second mixture; alternatively, the first process product, the second lithium source, and the titanium-containing compound can be mixed to obtain the second mixture. In some embodiments, the titanium-containing compound includes at least one of titanium oxides, hydroxides, carbonates, and phosphates. This effectively refines the grain size, promoting the acquisition of cathode materials with good grain size uniformity and high concentration, thereby improving the capacity and cycle performance of the cathode material.

[0065] According to embodiments of this application, the specific type of the second lithium source is not particularly limited and can be selected according to actual needs. In some embodiments, the second lithium source includes at least one of lithium hydroxide, lithium carbonate, lithium acetate, and lithium chloride. Therefore, the source is wide-ranging, the raw material quality is high, and the cost is low.

[0066] According to embodiments of this application, the ratio of the sum of the amounts of nickel, cobalt, and manganese elements in the nickel-cobalt-manganese precursor to the amount of lithium element in the second lithium source is 1:0.25~0.85, specifically 1:0.25, 1:0.3, 1:0.35, 1:0.4, 1:0.45, 1:0.5, 1:0.55, 1:0.6, 1:0.65, 1:0.7, 1:0.75, 1:0.8, 1:0.85, etc. Within the above ratio range, the Ostwald ripening process can be weakened during sintering, resulting in a cathode material with a right-skewed distribution while maintaining relatively uniform grain size.

[0067] Specifically, mixing the first-stage product with the lithium source added to the theoretical amount during the grain growth stage at a higher temperature, and precisely controlling the temperature of the second sintering process to weaken the Ostwald ripening process, can limit the spacing between the two peaks in the cathode material grain size distribution curve to be stable to less than 0.6 μm and the proportion of small particle peaks to be higher than that of large particle peaks. This allows the cathode material to have a right-skewed distribution characteristic while the grain size is relatively uniform.

[0068] According to embodiments of this application, there are no particular limitations on the specific method of mixing the first process product with the second lithium source; for example, a high-speed mixer or a soymilk maker can be used. This results in more uniform mixing, which is beneficial for obtaining a cathode material with better uniformity.

[0069] S40: The second mixture is subjected to a second sintering and the resulting secondary sintering product is subjected to a second crushing to obtain the second process product.

[0070] According to an embodiment of this application, the heating time for the second sintering is 2 hours to 10 hours, specifically 6 hours to 8 hours. As an example, the heating time for the first sintering is 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, etc. Within the above range, the raw materials can be heated uniformly, avoiding problems such as localized overheating.

[0071] According to an embodiment of this application, the temperature of the second sintering is 800℃~1100℃, specifically 900℃~1000℃. As an example, the temperature of the second sintering can specifically be 800℃, 900℃, 1000℃, 1100℃, etc. Within the above temperature range, the Ostwald ripening process can be precisely controlled, allowing the cathode material to exhibit right-skewed distribution characteristics while maintaining relatively uniform grain size.

[0072] According to an embodiment of this application, the holding time for the second sintering is 6h to 12h, specifically 8h to 10h. As an example, the holding time for the second sintering can be 6h, 7h, 8h, 9h, 10h, 11h, 12h, etc. Within the above range, the first-process product can be fully lithiated without wasting time.

[0073] According to embodiments of this application, the second crushing process can dissociate the products from the second sintering, reducing the adhesion of the cathode material and improving the particle independence of the cathode material. In some embodiments, the equipment used for the second crushing process can be one or more of a soybean milk maker, rotary mill, double roller mill, colloid mill, mechanical mill, and air jet mill.

[0074] S50: The second process product is mixed with the compound containing M to obtain a third mixture.

[0075] According to embodiments of this application, element M is at least one selected from B, Mg, Al, Si, P, Ti, Co, Sr, Y, Zr, Sb, La, and Ce. Compounds containing M include at least one selected from oxides, hydroxides, carbonates, and phosphates of element M. Therefore, the materials are widely available and have low cost.

[0076] According to embodiments of this application, there are no particular limitations on the specific method of mixing the second process product with the M-containing compound; for example, a high-speed mixer or a soymilk maker can be used for mixing. This results in more uniform mixing, which is beneficial for obtaining a cathode material with better uniformity.

[0077] S60: The third mixture is sintered for the third time to obtain the positive electrode material.

[0078] According to an embodiment of this application, the heating time for the third sintering is 2 hours to 10 hours, specifically 3 hours to 8 hours. As an example, the heating time for the third sintering can be 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, etc. Within the above range, the raw materials can be heated uniformly, avoiding problems such as localized overheating.

[0079] According to embodiments of this application, the temperature of the third sintering is 300℃~900℃, specifically 400℃~800℃. As an example, the temperature of the third sintering can specifically be 300℃, 400℃, 500℃, 600℃, 700℃, 800℃, 900℃, etc. Within the above range, the M-containing compound can effectively coat the surface of the cathode material. By constructing a stable coating layer through surface modification, the capacity decay caused by side reactions between the cathode material and the electrolyte during battery cycling can be mitigated.

[0080] According to an embodiment of this application, the holding time for the third sintering is 6h to 12h, specifically 8h to 10h. As an example, the holding time for the third sintering can be 6h, 7h, 8h, 9h, 10h, 11h, 12h, etc. Within the above range, effective formation of the coating layer can be promoted without wasting time.

[0081] According to embodiments of this application, in actual production, parameters can be adjusted based on experience to obtain cathode materials that meet target requirements. In some embodiments, given a fixed cathode material formulation, pre-sintering can be performed first, and then, based on the pre-sintering, sintering parameters can be adjusted empirically for re-sintering to obtain cathode materials that meet target parameters. As an example, the grain size μ' of the cathode material satisfies the following empirical formula: μ' = μ0 + 0.0125 × (t) y -t y0 )-0.094×(v-v0)+0.025× (t s - t s0 )+0.03×(T – T0) Where μ0 is the grain size of the pre-sintered cathode material, and t y0 t is the isothermal time for the first sintering during pre-firing. s0v0 is the isothermal time for the second sintering during pre-firing, v0 is the heating rate for the second sintering during pre-firing, and T0 is the temperature for the second sintering during pre-firing; t y The isothermal time t during the first sintering in the second sintering process y t s T1 represents the isothermal time of the second sintering in the re-sintering process, v represents the heating rate of the second sintering in the re-sintering process, and T2 represents the temperature of the second sintering in the re-sintering process.

[0082] Therefore, based on the guidance of the above empirical formulas, the sintering parameters can be adjusted in a targeted manner to quickly obtain cathode materials with the target parameters.

[0083] A third aspect of this application discloses a battery comprising the positive electrode material described in the first aspect of this application or the positive electrode material prepared by the method of the second aspect. Therefore, this battery has high energy density and excellent cycle performance under high voltage.

[0084] It is understandable that there are no particular restrictions on the specific type of battery; it can be a primary battery or a secondary battery. The shape of the battery can be cylindrical, square, or any other shape. According to the outer packaging, the battery can be a hard-shell battery, a soft-pack battery, etc.

[0085] Typically, a battery includes a positive electrode, a negative electrode, an electrolyte, and a separator. The positive electrode, negative electrode, and separator are fabricated into electrode assemblies using winding or stacking processes. The electrode assemblies and electrolyte are housed in an outer package. During charging and discharging, lithium ions repeatedly insert and extract between the positive and negative electrodes. The electrolyte acts as a conductor between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, primarily prevents short circuits while allowing lithium ions to pass through.

[0086] In some embodiments, the positive electrode sheet may include a positive current collector and a positive active material layer disposed on at least one side surface of the positive current collector. The positive active material layer includes the positive electrode material, conductive agent, and binder described above. The positive current collector may include a metal foil, for example, aluminum foil. The conductive agent may include acetylene black, single-walled carbon nanotubes, and materials conventional in the art. The binder may be polyvinylidene fluoride (PVDF) and materials conventional in the art.

[0087] In some embodiments, the negative electrode sheet may include a negative electrode current collector and a layer of negative electrode active material disposed on at least one side surface of the negative electrode current collector. The negative electrode active material layer may include a negative electrode active material, a thickener, a conductive agent, and a binder. The negative electrode current collector may be a metal foil, for example, copper foil. The negative electrode active material may include artificial graphite, natural graphite, silicon-carbon based composite materials, lithium metal composite materials, lithium metal materials, and other commonly used negative electrode active materials in the art. The thickener may be sodium carboxymethyl cellulose (CMC-Na) and other conventional materials in the art. The conductive agent may be acetylene black and other conventional materials in the art. The binder may be styrene-butadiene rubber and other conventional materials in the art.

[0088] In some embodiments, the separator may be a separator known in the art that can be used in lithium-ion batteries and is stable to the electrolyte used, such as a polyethylene separator, a polypropylene separator, a polyethylene / polypropylene composite separator, etc.

[0089] A fourth aspect of this application discloses an electrical device comprising the positive electrode material described in the first aspect, the positive electrode material prepared by the method of the second aspect, or the battery described in the third aspect. This electrical device possesses all the features and advantages of the lithium-ion battery described above, which will not be repeated here.

[0090] In some embodiments, the electrical device may include, but is not limited to, mobile devices (e.g., mobile phones, laptops, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.

[0091] The embodiments of this application are described in detail below.

[0092] Example 1 Ni cobalt manganese hydroxide precursor Ni 0.6 Co 0.1 Mn 0.3(OH)2, lithium carbonate and TiO2 are mixed using a high-speed mixer at a molar ratio of n(Ni+Co+Mn):n(Li):n(Ti) = 1:0.50:0.0004. The resulting mixture I is heated to 800℃ in air for 6 hours and sintered at that temperature for 8 hours. After being crushed in a soymilk maker, the cathode material process product I is obtained. Then, the obtained process product I is mixed with lithium carbonate at a molar ratio of n(Ni+Co+Mn):n(Li) = 1:0.55. For example, a high-speed mixer is used for mixing. The resulting mixture II is heated to 960℃ in an oxygen atmosphere for 6 hours and sintered at a constant temperature for 8 hours. After being crushed to the target particle size using a soymilk maker, the cathode material process product II is obtained. Then, cathode material process product II is mixed with Al2O3 at a molar ratio of n(Ni+Co+Mn):n(Al) = 1:0.002 and sintered three times in an air atmosphere: heated to 700℃ for 4 hours and sintered at a constant temperature for 8 hours to obtain the finished nickel-cobalt-manganese cathode material Li(Ni) 0.6 Co 0.1 Mn 0.3 Ti 0.0004 Al 0.002 O2 has an average grain size μ of 1.60 μm.

[0093] Battery assembly: The obtained single-crystal cathode material, polyvinylidene fluoride, N... methyl 2 Pyrrolidone was mixed and ground in a mass ratio of 95:2:3, coated onto aluminum foil, and then vacuum dried, rolled, and cut to form a positive electrode sheet with a diameter of 12 mm. Then, coin cells were fabricated in a glove box under argon atmosphere protection. A 14 mm diameter lithium sheet was used as the negative electrode, a polypropylene microporous membrane was used as the separator, and an equal mixture of 1 mol / L lithium hexafluorophosphate, ethylene carbonate, and diethyl carbonate was used as the electrolyte. After assembly, a CR2025 coin cell was obtained.

[0094] Example 2 Ni cobalt manganese hydroxide precursor Ni 0.6 Co 0.1 Mn 0.3(OH)₂ and lithium carbonate were mixed in a high-speed mixer at a molar ratio of n(Ni+Co+Mn):n(Li) = 1:0.5. The resulting mixture I was heated to 800℃ in air for 6 hours and sintered at a constant temperature for 8 hours. After being crushed in a soymilk maker, the cathode material process product I was obtained. The obtained process product I was then mixed with lithium carbonate in a molar ratio of n(Ni+Co+Mn):n(Li) = 1:0.55 using a high-speed mixer. The resulting mixture II was heated to 960℃ in oxygen for 6 hours and sintered at a constant temperature for 8 hours. After being crushed in a soymilk maker to the target particle size, the cathode material process product II was obtained. The cathode material process product II was then mixed with Al₂O₃ in a molar ratio of n(Ni+Co+Mn):n(Al) = 1:0.002 and sintered three times in air: heated to 700℃ for 4 hours and sintered at a constant temperature for 8 hours to obtain the finished nickel-cobalt-manganese cathode material Li(Ni) 0.6 Co 0.1 Mn 0.3 Al 0.002 O2 has an average grain size μ of 1.60 μm.

[0095] The button cell battery assembly is the same as in Example 1.

[0096] Example 3 Ni cobalt manganese hydroxide precursor Ni 0.6 Co 0.1 Mn 0.3 (OH)2, lithium carbonate and TiO2 are mixed using a high-speed mixer at a molar ratio of n(Ni+Co+Mn):n(Li):n(Ti) = 1:0.50:0.0004. The resulting mixture I is heated to 800℃ in air for 6 hours and sintered at that temperature for 12 hours. After being crushed in a soymilk maker, the cathode material process product I is obtained. Then, the obtained process product I is mixed with lithium carbonate at a molar ratio of n(Ni+Co+Mn):n(Li) = 1:0.55. The mixture was prepared using a high-speed mixer. The resulting mixture II was heated to 977℃ in an oxygen atmosphere for 8 hours and sintered at a constant temperature for 8 hours. After being crushed to the target particle size using a soybean milk maker, the cathode material process product II was obtained. The cathode material process product II was then mixed with Al2O3 at a ratio of n(Ni+Co+Mn):n(Al) = 1:0.002 and sintered three times in an air atmosphere: heated to 700℃ for 4 hours and sintered at a constant temperature for 8 hours to obtain the finished nickel-cobalt-manganese cathode material Li(Ni) 0.6 Co 0.1 Mn 0.3 Ti 0.0004 Al 0.002 O2 has an average grain size μ of 2.18 μm.

[0097] The button cell battery assembly is the same as in Example 1.

[0098] Example 4 Ni cobalt manganese hydroxide precursor Ni 0.6 Co 0.1 Mn 0.3 (OH)2, lithium carbonate and TiO2 are mixed using a high-speed mixer at a molar ratio of n(Ni+Co+Mn):n(Li):n(Ti) = 1:0.50:0.0004. The resulting mixture I is heated to 800℃ in air for 6 hours and sintered at that temperature for 8 hours. After being crushed in a soymilk maker, the cathode material process product I is obtained. Then, the obtained process product I is mixed with lithium carbonate at a molar ratio of n(Ni+Co+Mn):n(Li) = 1:0.55. The mixture was prepared using a high-speed mixer. The resulting mixture II was heated to 963℃ in an oxygen atmosphere for 8 hours and sintered at a constant temperature for 8 hours. After being crushed to the target particle size using a soybean milk maker, the cathode material process product II was obtained. The cathode material process product II was then mixed with Al2O3 at a ratio of n(Ni+Co+Mn):n(Al) = 1:0.002 and sintered three times in an air atmosphere: heated to 700℃ for 4 hours and sintered at a constant temperature for 8 hours to obtain the finished nickel-cobalt-manganese cathode material Li(Ni) 0.6 Co 0.1 Mn 0.3 Ti 0.0004 Al 0.002 O2 has an average grain size μ of 1.75 μm.

[0099] The button cell battery assembly is the same as in Example 1.

[0100] Example 5 Ni cobalt manganese hydroxide precursor Ni 0.6 Co 0.1 Mn 0.3 (OH)2, lithium carbonate and TiO2 are mixed using a high-speed mixer at a molar ratio of n(Ni+Co+Mn):n(Li):n(Ti) = 1:0.50:0.0004. The resulting mixture I is heated to 800℃ in air for 6 hours and sintered at that temperature for 8 hours. After being crushed in a soymilk maker, the cathode material process product I is obtained. Then, the obtained process product I is mixed with lithium carbonate at a molar ratio of n(Ni+Co+Mn):n(Li) = 1:0.55. The mixture was prepared using a high-speed mixer. The resulting mixture II was heated to 957°C in an oxygen atmosphere for 8 hours and sintered at a constant temperature for 8 hours. After being crushed to the target particle size using a soybean milk maker, the cathode material process product II was obtained. The cathode material process product II was then mixed with Al2O3 at a ratio of n(Ni+Co+Mn):n(Al) = 1:0.002 and sintered three times in an air atmosphere: heated to 700°C for 4 hours and sintered at a constant temperature for 8 hours to obtain the finished nickel-cobalt-manganese cathode material Li(Ni) 0.6 Co 0.1 Mn 0.3 Ti 0.0004 Al0.002 O2 has an average grain size μ of 1.52 μm.

[0101] The button cell battery assembly is the same as in Example 1.

[0102] Example 6 Ni cobalt manganese hydroxide precursor Ni 0.6 Co 0.1 Mn 0.3 (OH)2, lithium carbonate and TiO2 are mixed using a high-speed mixer at a molar ratio of n(Ni+Co+Mn):n(Li):n(Ti) = 1:0.50:0.0004. The resulting mixture I is heated to 800℃ in air for 6 hours and sintered at that temperature for 6 hours. After being crushed in a soymilk maker, the cathode material process product I is obtained. Then, the obtained process product I is mixed with lithium carbonate at a molar ratio of n(Ni+Co+Mn):n(Li) = 1:0.55. For example, a high-speed mixer is used for mixing. The resulting mixture II is heated to 961°C in an oxygen atmosphere for 3 hours and sintered at a constant temperature for 10 hours. After being crushed to the target particle size using a soymilk maker, the cathode material process product II is obtained. The cathode material process product II is then mixed with Al2O3 at a ratio of n(Ni+Co+Mn):n(Al) = 1:0.002 and sintered three times in an air atmosphere: heated to 700°C for 4 hours and sintered at a constant temperature for 8 hours to obtain the finished nickel-cobalt-manganese cathode material Li(Ni) 0.6 Co 0.1 Mn 0.3 Ti 0.0004 Al 0.002 O2 has an average grain size μ of 1.43 μm.

[0103] The button cell battery assembly is the same as in Example 1.

[0104] Example 7 Ni cobalt manganese hydroxide precursor Ni 0.6 Co 0.1 Mn 0.3(OH)2, lithium carbonate and TiO2 are mixed using a high-speed mixer at a molar ratio of n(Ni+Co+Mn):n(Li):n(Ti) = 1:0.50:0.0004. The resulting mixture I is heated to 800℃ in air for 6 hours and sintered at that temperature for 8 hours. After being crushed in a soymilk maker, the cathode material process product I is obtained. Then, the obtained process product I is mixed with lithium carbonate at a molar ratio of n(Ni+Co+Mn):n(Li) = 1:0.55. For example, a high-speed mixer is used for mixing. The resulting mixture II is heated to 963℃ in an oxygen atmosphere for 8 hours and sintered at a constant temperature for 10 hours. After being crushed to the target particle size using a soymilk maker, the cathode material process product II is obtained. The cathode material process product II is then mixed with Al2O3 at a ratio of n(Ni+Co+Mn):n(Al) = 1:0.002 and sintered three times in an air atmosphere: heated to 700℃ for 4 hours and sintered at a constant temperature for 8 hours to obtain the finished nickel-cobalt-manganese cathode material Li(Ni) 0.6 Co 0.1 Mn 0.3 Ti 0.0004 Al 0.002 O2 has an average grain size μ of 1.80 μm.

[0105] The button cell battery assembly is the same as in Example 1.

[0106] Example 8 Ni cobalt manganese hydroxide precursor Ni 0.6 Co 0.1 Mn 0.3 (OH)2, lithium carbonate and TiO2 are mixed using a high-speed mixer at a molar ratio of n(Ni+Co+Mn):n(Li):n(Ti) = 1:0.50:0.0004. The resulting mixture I is heated to 800℃ in air for 6 hours and sintered at that temperature for 8 hours. After being crushed in a soymilk maker, the cathode material process product I is obtained. Then, the obtained process product I is mixed with lithium carbonate at a molar ratio of n(Ni+Co+Mn):n(Li) = 1:0.55 using a high-speed mixer. The mixture was mixed in a mixer, and the resulting mixture II was heated to 960℃ in an oxygen atmosphere for 6 hours and sintered at a constant temperature for 8 hours. After being crushed in a soybean milk maker, the positive electrode material process product II was obtained (the crushing time was twice that of Comparative Example 2). The positive electrode material process product II was then mixed with Al2O3 at a ratio of n(Ni+Co+Mn):n(Al) = 1:0.002, and sintered three times in an air atmosphere: heated to 700℃ for 4 hours and sintered at a constant temperature for 8 hours, to obtain the finished nickel-cobalt-manganese positive electrode material Li(Ni) 0.6 Co 0.1 Mn 0.3 Ti 0.0004 Al 0.002 O2 has an average grain size μ of 1.60 μm.

[0107] The button cell battery assembly is the same as in Example 1.

[0108] Example 9 Ni cobalt manganese hydroxide precursor Ni 0.6 Co 0.1 Mn 0.3 (OH)2, lithium carbonate and TiO2 are mixed in a high-speed mixer at a molar ratio of n(Ni+Co+Mn):n(Li):n(Ti) = 1:0.50:0.0004. The resulting mixture I is heated to 800℃ in air for 6 hours and sintered at that temperature for 8 hours. After being crushed in a soymilk maker, the cathode material process product I is obtained. Then, the obtained process product I is mixed with lithium carbonate in a molar ratio of n(Ni+Co+Mn):n(Li) = 1:0.55 and further mixed in a high-speed mixer. The mixture was then heated to 960°C in an oxygen atmosphere for 6 hours and sintered at a constant temperature for 8 hours. The mixture was then crushed to the target particle size using a soybean milk maker to obtain cathode material process product II (the crushing time was extended by 0.5 times compared to Example 1). Cathode material process product II was then mixed with Al2O3 at a ratio of n(Ni+Co+Mn):n(Al) = 1:0.002, and sintered three times in an air atmosphere: heated to 700°C for 4 hours and sintered at a constant temperature for 8 hours to obtain the finished nickel-cobalt-manganese cathode material Li(Ni) 0.6 Co 0.1 Mn 0.3 Ti 0.0004 Al 0.002 O2 has an average grain size μ of 1.60 μm.

[0109] The button cell battery assembly is the same as in Example 1.

[0110] Example 10 Ni cobalt manganese hydroxide precursor Ni 0.6 Co 0.1 Mn 0.3(OH)2, lithium carbonate and TiO2 are mixed in a high-speed mixer at a molar ratio of n(Ni+Co+Mn):n(Li):n(Ti) = 1:0.50:0.0004. The resulting mixture I is heated to 800℃ in air for 6 hours and sintered at that temperature for 8 hours. After being crushed in a soymilk maker, the cathode material process product I is obtained. Then, the obtained process product I is mixed with lithium carbonate in a molar ratio of n(Ni+Co+Mn):n(Li) = 1:0.55 and further mixed in a high-speed mixer. The mixture was then heated to 960°C in an oxygen atmosphere for 6 hours and sintered at a constant temperature for 8 hours. The mixture was then crushed to the target particle size using a soybean milk maker to obtain cathode material process product II (the crushing time was shortened by 0.1 times compared to Example 1). Cathode material process product II was then mixed with Al2O3 at a ratio of n(Ni+Co+Mn):n(Al) = 1:0.002, and sintered three times in an air atmosphere: heated to 700°C for 4 hours and sintered at a constant temperature for 8 hours to obtain the finished nickel-cobalt-manganese cathode material Li(Ni) 0.6 Co 0.1 Mn 0.3 Ti 0.0004 Al 0.002 O2 has an average grain size μ of 1.60 μm.

[0111] The button cell battery assembly is the same as in Example 1.

[0112] Example 11 Ni cobalt manganese hydroxide precursor Ni 0.6 Co 0.1 Mn 0.3 (OH)2, lithium carbonate and TiO2 are mixed in a high-speed mixer at a molar ratio of n(Ni+Co+Mn):n(Li):n(Ti) = 1:0.50:0.0004. The resulting mixture I is heated to 800℃ in air for 6 hours and sintered at that temperature for 8 hours. After being crushed in a soymilk maker, the cathode material process product I is obtained. Then, the obtained process product I is mixed with lithium carbonate in a molar ratio of n(Ni+Co+Mn):n(Li) = 1:0.55 and further mixed in a high-speed mixer. The mixture was then heated to 960°C in an oxygen atmosphere for 6 hours and sintered at a constant temperature for 8 hours. The mixture was then crushed to the target particle size using a soybean milk maker to obtain cathode material process product II (the crushing time was shortened by 0.2 times compared to Example 1). Cathode material process product II was then mixed with Al2O3 at a ratio of n(Ni+Co+Mn):n(Al) = 1:0.002, and sintered three times in an air atmosphere: heated to 700°C for 4 hours and sintered at a constant temperature for 8 hours to obtain the finished nickel-cobalt-manganese cathode material Li(Ni) 0.6 Co 0.1 Mn 0.3 Ti 0.0004 Al 0.002 O2 has an average grain size μ of 1.60 μm.

[0113] The button cell battery assembly is the same as in Example 1.

[0114] Example 12 Ni cobalt manganese hydroxide precursor Ni 0.6 Co 0.1 Mn 0.3 (OH)2, lithium carbonate, and TiO2 were mixed using a high-speed mixer at a molar ratio of n(Ni+Co+Mn):n(Li):n(Ti) = 1:0.7:0.0004. The resulting mixture I was heated to 800℃ in an oxygen atmosphere for 6 hours and sintered at that temperature for 8 hours. After being crushed in a soymilk maker, the positive electrode material process product I was obtained. Then, the obtained process product I was mixed with lithium hydroxide at a molar ratio of n(Ni+Co+Mn):n(Li) = 1:0.35. The mixture was prepared using a high-speed mixer. The resulting mixture II was heated to 959°C in an oxygen atmosphere for 6 hours and sintered at a constant temperature for 8 hours. After being crushed to the target particle size using a soybean milk maker, the cathode material process product II was obtained. The cathode material process product II was then mixed with Al2O3 at a ratio of n(Ni+Co+Mn):n(Al) = 1:0.002 and sintered three times in an air atmosphere: heated to 700°C for 4 hours and sintered at a constant temperature for 8 hours to obtain the finished nickel-cobalt-manganese cathode material Li(Ni) 0.6 Co 0.1 Mn 0.3 Ti 0.0004 Al 0.002 O2 has an average grain size μ of 1.60 μm.

[0115] The button cell battery assembly is the same as in Example 1.

[0116] Example 13 Ni cobalt manganese hydroxide precursor Ni 0.6 Co 0.1 Mn 0.3 (OH)2, lithium carbonate, and TiO2 were mixed using a high-speed mixer at a molar ratio of n(Ni+Co+Mn):n(Li):n(Ti) = 1:0.5:0.0004. The resulting mixture I was heated to 800℃ in an oxygen atmosphere for 6 hours and sintered at that temperature for 8 hours. After being crushed in a soymilk maker, the cathode material process product I was obtained. Then, the obtained process product I was mixed with lithium hydroxide at a molar ratio of n(Ni+Co+Mn):n(Li) = 1:0.55. The mixture was prepared using a high-speed mixer. The resulting mixture II was heated to 960℃ in an oxygen atmosphere for 6 hours and sintered at a constant temperature for 8 hours. After being crushed to the target particle size using a soybean milk maker, the cathode material process product II was obtained. The cathode material process product II was then mixed with Al2O3 at a ratio of n(Ni+Co+Mn):n(Al) = 1:0.002 and sintered three times in an air atmosphere: heated to 700℃ for 4 hours and sintered at a constant temperature for 8 hours to obtain the finished nickel-cobalt-manganese cathode material Li(Ni)0.6 Co 0.1 Mn 0.3 Ti 0.0004 Al 0.002 O2 has an average grain size μ of 1.60 μm.

[0117] The button cell battery assembly is the same as in Example 1.

[0118] Example 14 Ni cobalt manganese hydroxide precursor Ni 0.6 Co 0.1 Mn 0.3 (OH)2 and lithium carbonate are mixed in a high-speed mixer at a molar ratio of n(Ni+Co+Mn):n(Li) = 1:0.5. The resulting mixture I is heated to 800℃ in an oxygen atmosphere for 6 hours and sintered at a constant temperature for 8 hours. After being crushed in a soybean milk machine, the cathode material process product I is obtained. Then, the obtained process product I, lithium hydroxide, and TiO2 are mixed in a molar ratio of n(Ni+Co+Mn):n(Li):n(Ti) = 1:0.55:0.0004. The mixture was prepared using a high-speed mixer. The resulting mixture II was heated to 960℃ in an oxygen atmosphere for 6 hours and sintered at a constant temperature for 8 hours. After being crushed to the target particle size using a soybean milk maker, the cathode material process product II was obtained. The cathode material process product II was then mixed with Al2O3 at a ratio of n(Ni+Co+Mn):n(Al) = 1:0.002 and sintered three times in an air atmosphere: heated to 700℃ for 4 hours and sintered at a constant temperature for 8 hours to obtain the finished nickel-cobalt-manganese cathode material Li(Ni) 0.6 Co 0.1 Mn 0.3 Ti 0.0004 Al 0.002 O2 has an average grain size μ of 1.60 μm.

[0119] The button cell battery assembly is the same as in Example 1.

[0120] Example 15 Ni cobalt manganese hydroxide precursor Ni 0.6 Co 0.1 Mn 0.3(OH)2, lithium carbonate and TiO2 are mixed using a high-speed mixer at a molar ratio of n(Ni+Co+Mn):n(Li):n(Ti) = 1:0.60:0.0004. The resulting mixture I is heated to 800℃ in air for 6 hours and sintered at that temperature for 8 hours. After being crushed in a soymilk maker, the cathode material process product I is obtained. Then, the obtained process product I is mixed with lithium carbonate at a molar ratio of n(Ni+Co+Mn):n(Li) = 1:0.55. The mixture was prepared using a high-speed mixer. The resulting mixture II was heated to 940℃ in an oxygen atmosphere for 6 hours and sintered at a constant temperature for 8 hours. After being crushed to the target particle size using a soybean milk machine, the cathode material process product II was obtained. The cathode material process product II was then mixed with WO3 at a molar ratio of n(Ni+Co+Mn):n(W) = 1:0.002 and sintered three times in an air atmosphere: heated to 700℃ for 4 hours and sintered at a constant temperature for 8 hours to obtain the finished nickel-cobalt-manganese cathode material Li(Ni) 0.7 Co 0.1 Mn 0.2 Ti 0.0004 W 0.002 O2 has an average grain size μ of 1.80 μm.

[0121] The button cell battery assembly is the same as in Example 1.

[0122] Example 16 Ni cobalt manganese hydroxide precursor Ni 0.6 Co 0.1 Mn 0.3 (OH)2, lithium carbonate and TiO2 are mixed using a high-speed mixer at a molar ratio of n(Ni+Co+Mn):n(Li):n(Ti) = 1:0.80:0.0004. The resulting mixture I is heated to 800℃ in air for 6 hours and sintered at that temperature for 8 hours. After being crushed in a soymilk maker, the cathode material process product I is obtained. Then, the obtained process product I is mixed with lithium carbonate at a molar ratio of n(Ni+Co+Mn):n(Li) = 1:0.55. The mixture was prepared using a high-speed mixer. The resulting mixture II was heated to 803℃ in an oxygen atmosphere for 6 hours and sintered at a constant temperature for 8 hours. After being crushed to the target particle size using a soybean milk maker, the cathode material process product II was obtained. The cathode material process product II was then mixed with SrO at a molar ratio of n(Ni+Co+Mn):n(Sr) = 1:0.001 and sintered three times in an air atmosphere: heated to 700℃ for 4 hours and sintered at a constant temperature for 8 hours to obtain the finished nickel-cobalt-manganese cathode material Li(Ni) 0.9 Co 0.05 Mn 0.05 Ti 0.0004 Sr 0.001 O2 has an average grain size μ of 1.80 μm.

[0123] The button cell battery assembly is the same as in Example 1.

[0124] Comparative Example 1 Ni cobalt manganese hydroxide precursor Ni 0.6 Co 0.1 Mn 0.3 (OH)2, lithium carbonate and TiO2 are mixed using a high-speed mixer at a molar ratio of n(Ni+Co+Mn):n(Li):n(Ti) = 1:1.05:0.0004. The resulting mixture I is heated to 969℃ in air for 4 hours and sintered at a constant temperature for 12 hours. After being crushed to the target particle size using a soymilk maker, the cathode material process product I is obtained. The cathode material process product I is then mixed with Al2O3 at a ratio of n(Ni+Co+Mn):n(Al) = 1:0.002 and sintered a second time in air: heated to 700℃ in 4 hours and sintered at a constant temperature for 8 hours to obtain the finished nickel-cobalt-manganese cathode material Li(Ni) 0.6 Co 0.1 Mn 0.3 Ti 0.0004 Al 0.002 O2 has an average grain size μ of 1.80 μm.

[0125] The button cell battery assembly is the same as in Example 1.

[0126] Comparative Example 2 Ni cobalt manganese hydroxide precursor Ni 0.6 Co 0.1 Mn 0.3 (OH)2, lithium carbonate and TiO2 are mixed using a high-speed mixer at a molar ratio of n(Ni+Co+Mn):n(Li):n(Ti) = 1:1.05:0.0004. The resulting mixture I is heated to 973℃ in air for 6 hours and sintered at a constant temperature for 10 hours. After being crushed to the target particle size using a soymilk maker, the cathode material process product I is obtained. The cathode material process product I is then mixed with Al2O3 at a ratio of n(Ni+Co+Mn):n(Al) = 1:0.002 and sintered a second time in air: heated to 700℃ in 4 hours and sintered at a constant temperature for 8 hours to obtain the finished nickel-cobalt-manganese cathode material Li(Ni) 0.6 Co 0.1 Mn 0.3 Ti 0.0004 Al 0.002 O2 has an average grain size μ of 2.0 μm.

[0127] The button cell battery assembly is the same as in Example 1.

[0128] Comparative Example 3 Ni cobalt manganese hydroxide precursor Ni 0.6 Co 0.1 Mn 0.3(OH)2, lithium carbonate and TiO2 are mixed using a high-speed mixer at a molar ratio of n(Ni+Co+Mn):n(Li):n(Ti) = 1:0.50:0.0004. The resulting mixture I is heated to 800℃ in air for 6 hours and sintered at that temperature for 8 hours. After being crushed in a soymilk maker, the cathode material process product I is obtained. Then, the obtained process product I is mixed with lithium carbonate at a molar ratio of n(Ni+Co+Mn):n(Li) = 1:0.55 using a high-speed mixer. The mixture was prepared by mixing, and the resulting mixture II was heated to 960°C in an oxygen atmosphere for 6 hours and sintered at a constant temperature for 8 hours. The mixture was then crushed to the target particle size using a soybean milk maker to obtain cathode material process product II (the crushing time was extended by 2 times compared to Example 1). Cathode material process product II was then mixed with Al2O3 at a ratio of n(Ni+Co+Mn):n(Al) = 1:0.002, and sintered three times in an air atmosphere: heated to 700°C for 4 hours and sintered at a constant temperature for 8 hours to obtain the finished nickel-cobalt-manganese cathode material Li(Ni) 0.6 Co 0.1 Mn 0.3 Ti 0.0004 Al 0.002 O2 has an average grain size μ of 1.60 μm.

[0129] The button cell battery assembly is the same as in Example 1.

[0130] Comparative Example 4 Ni cobalt manganese hydroxide precursor Ni 0.6 Co 0.1 Mn 0.3 (OH)2, lithium carbonate and TiO2 are mixed using a high-speed mixer at a molar ratio of n(Ni+Co+Mn):n(Li):n(Ti) = 1:1.05:0.0004. The resulting mixture I is heated to 967℃ in air for 6 hours and sintered at a constant temperature for 10 hours. After being crushed to the target particle size using a soymilk maker, the cathode material process product I is obtained. The cathode material process product I is then mixed with Al2O3 at a ratio of n(Ni+Co+Mn):n(Al) = 1:0.002 and sintered a second time in air: heated to 700℃ in 4 hours and sintered at a constant temperature for 8 hours to obtain the finished nickel-cobalt-manganese cathode material Li(Ni) 0.6 Co 0.1 Mn 0.3 Ti 0.0004 Al 0.002 O2 has an average grain size μ of 1.81 μm.

[0131] The button cell battery assembly is the same as in Example 1.

[0132] Comparative Example 5 Ni cobalt manganese hydroxide precursor Ni 0.6 Co 0.1 Mn0.3 (OH)2, lithium carbonate and TiO2 were mixed using a high-speed mixer at a molar ratio of n(Ni+Co+Mn):n(Li):n(Ti) = 1:1.05:0.0004. The resulting mixture I was heated to 973℃ in air for 6 hours and sintered at a constant temperature for 10 hours. The mixture was then crushed to the target particle size using a soymilk maker to obtain cathode material process product I (the crushing time was extended by 2 times compared to Comparative Example 2). Cathode material process product I was then mixed with Al2O3 at a ratio of n(Ni+Co+Mn):n(Al) = 1:0.002 and sintered a second time in air: the temperature was raised to 700℃ in 4 hours and sintered at a constant temperature for 8 hours to obtain the finished nickel-cobalt-manganese cathode material Li(Ni 0.6 Co 0.1 Mn 0.3 Ti 0.0004 Al 0.002 O2 has an average grain size μ of 2.0 μm.

[0133] The button cell battery assembly is the same as in Example 1.

[0134] Comparative Example 6 Ni cobalt manganese hydroxide precursor Ni 0.6 Co 0.1 Mn 0.3 (OH)2, lithium carbonate and TiO2 were mixed using a high-speed mixer at a molar ratio of n(Ni+Co+Mn):n(Li):n(Ti) = 1:1.05:0.0004. The resulting mixture I was heated to 969℃ in air for 4 hours and sintered at that temperature for 12 hours. The mixture was then crushed to the target particle size using a soymilk maker to obtain cathode material process product I (the crushing time was extended by 2 times compared to Comparative Example 1). Cathode material process product I was then mixed with Al2O3 at a ratio of n(Ni+Co+Mn):n(Al) = 1:0.002 and sintered a second time in air: the temperature was raised to 700℃ in 4 hours and sintered at that temperature for 8 hours to obtain the finished nickel-cobalt-manganese cathode material Li(Ni 0.6 Co 0.1 Mn 0.3 Ti 0.0004 Al 0.002 O2 has an average grain size μ of 1.80 μm.

[0135] The button cell battery assembly is the same as in Example 1.

[0136] Comparative Example 7 Ni cobalt manganese hydroxide precursor Ni 0.6 Co 0.1 Mn 0.3(OH)2, lithium carbonate and TiO2 were mixed using a high-speed mixer at a molar ratio of n(Ni+Co+Mn):n(Li):n(Ti) = 1:1.05:0.0004. The resulting mixture I was heated to 967℃ in air for 6 hours and sintered at that temperature for 10 hours. The mixture was then crushed to the target particle size using a soymilk maker to obtain cathode material process product I (the crushing time was extended by 2 times compared to Comparative Example 4). Cathode material process product I was then mixed with Al2O3 at a ratio of n(Ni+Co+Mn):n(Al) = 1:0.002 and sintered a second time in air: the temperature was raised to 700℃ in 4 hours and sintered at that temperature for 8 hours to obtain the finished nickel-cobalt-manganese cathode material Li(Ni 0.6 Co 0.1 Mn 0.3 Ti 0.0004 Al 0.002 O2 has an average grain size μ of 1.81 μm.

[0137] The button cell battery assembly is the same as in Example 1.

[0138] Performance testing: 1. Average grain size μ: The average grain size X of the single-crystal nickel-cobalt-manganese ternary cathode active material was obtained by measuring the projected area of ​​each single-crystal particle in the electron microscope using a Hitachi S-4800 scanning electron microscope. The specific method was to convert the projected area of ​​500 random particles in the scanning electron microscope image into a standard circle of equal area and then calculate the average diameter, which is the average grain size μ of the single-crystal nickel-cobalt-manganese ternary cathode active material.

[0139] 2. Ellipticity P: The ellipticity P of the single-crystal nickel-cobalt-manganese ternary cathode active material particles was obtained by testing with a Hitachi S-4800 scanning electron microscope from Japan. The projected area of ​​each single-crystal particle in the electron microscope was statistically analyzed, and then the grain size was calculated. Specifically, the average value of the ratio of the difference between the longest and shortest diagonals of the projected area of ​​500 random particles in the scanning electron microscope image to the particle size was calculated using software with arbitrary grain size.

[0140] 3. Skewness coefficient and kurtosis coefficient: The skewness coefficient measures the symmetry of a data distribution using the third central moment. The formula for the skewness coefficient is: Sk = E[(X...] μ) 3 ] / σ 3 ; where E[(X μ) 3[ ] represents the third central moment, X is the grain size, μ is the average grain size, and σ is the standard deviation. The testing methods for grain size X and average grain size μ are the same as in performance testing method 1. The skewness coefficient S is obtained through calculation. k Skewness coefficient S k A value of 0 indicates a symmetrical distribution; the skewness coefficient S k A value greater than 0 indicates positive skewness; the skewness coefficient S k A value less than 0 indicates a negatively skewed state.

[0141] 4. The formula for the kurtosis coefficient (or kurtosis factor) K is: Kurtosis coefficient = E[(X μ) 4 ] / σ 4 , where E[(X μ) 4 ] is the fourth central moment, X is the grain size, μ is the average grain size, and σ is the standard deviation. The testing methods for grain size X and average grain size μ are the same as those for performance testing method 1. The kurtosis coefficient K is obtained through calculation. A kurtosis coefficient of 3 indicates a normal peak distribution; greater than 3 indicates a sharp peak; and less than 3 indicates a flat peak.

[0142] 5. D 10 D 50 D 90 K 90 : Median particle size D in volume distribution 10 D 50 D 90 K 90 The particle size distribution was obtained using a Marvern Mastersizer 3000 laser particle size analyzer.

[0143] The formula for calculating K90 is: K 90 =(D 90 -D 10 ) / D 50 .

[0144] 6. Battery performance test: The electrochemical performance of CR2025 coin cells was tested using the Shenzhen Xinwei Battery Testing System. The charge / discharge voltage range was controlled between 3.0V and 4.45V. At room temperature, the coin cells were charged and discharged at 0.3C to evaluate the charge / discharge specific capacity of the monocrystalline nickel-cobalt-manganese ternary cathode material.

[0145] The specific manufacturing process of the 2025 coin cell is as follows: Preparation of the positive electrode sheet: The positive electrode active material, acetylene black, and polyvinylidene fluoride (PVDF) were thoroughly mixed with an appropriate amount of N-methylpyrrolidone (NMP) at a mass ratio of 95:3:2 to form a uniform slurry. The slurry was coated onto both sides of an aluminum foil and dried at 120°C for 12 hours. Then, it was pressed into shape using a pressure of 100 MPa to produce a positive electrode sheet with a diameter of 12 mm and a thickness of 120 μm. The loading of the positive electrode active material on the aluminum foil was 15-16 mg / cm³. 2 ; In an argon-filled glove box with both water and oxygen content less than 5 ppm, the positive electrode, separator, negative electrode, and electrolyte were assembled into a 2025 coin cell and left to stand for 6 hours. The negative electrode used a 17 mm diameter, 1 mm thick lithium metal sheet; the separator used a 25 μm thick polyethylene porous membrane (Celgard 2325); the electrolyte included lithium salt LiPF6 and a solvent (ethylene carbonate (EC) and diethyl carbonate (DEC) in a 1:1 volume ratio), with a LiPF6 concentration of 1 mol / L.

[0146] 5.1V, 4.45V 0.1C Capacity: The electrochemical performance of CR2025 coin cells was tested using the Shenzhen Xinwei Battery Testing System. The charge / discharge voltage range was controlled between 3.0V and 4.45V. At room temperature, the coin cells were charged and discharged at 0.1C to evaluate the charge / discharge specific capacity of the monocrystalline nickel-cobalt-manganese ternary cathode material.

[0147] 5.2, 4.45V 0.3C Capacity: The electrochemical performance of CR2025 coin cells was tested using the Shenzhen Xinwei Battery Testing System. The charge / discharge voltage range was controlled between 3.0V and 4.45V. At room temperature, the coin cells were charged and discharged at 0.3C to evaluate the charge / discharge specific capacity of the monocrystalline nickel-cobalt-manganese ternary cathode material.

[0148] 5.3. Cyclic life at room temperature: The electrochemical performance of CR2025 coin cells was tested using the Shenzhen Xinwei Battery Testing System. At 25℃, the charge / discharge voltage range was controlled between 3.0V and 4.45V. Constant current charging and discharging was performed at 1C until the discharge capacity decayed to 80% of the initial discharge specific capacity, thus evaluating the room-temperature cycle life of the single-crystal nickel-cobalt-manganese ternary cathode material.

[0149] 5.4 High-temperature cycle life: The electrochemical performance of CR2025 coin cells was tested using the Shenzhen Xinwei Battery Testing System. At 45℃, the charge / discharge voltage range was controlled between 3.0V and 4.45V. Constant current charging and discharging was performed at 1C until the discharge capacity decayed to 80% of the initial discharge specific capacity, thus evaluating the high-temperature cycle life of the monocrystalline nickel-cobalt-manganese ternary cathode material.

[0150] Table 1: Cathode Material Parameters

[0151] Table 2: Performance Test Results

[0152] Figure 1 The image shows a SEM image of the single-crystal cathode material in Example 1. The single-crystal particles are rounded and dispersed, exhibiting good independence. The cathode material in Example 1 demonstrates excellent capacity and cycle life.

[0153] As can be seen from the results in Tables 1 and 2, the synthesis scheme provided in this application can effectively improve the roundness of single crystal particles and obtain single crystal cathode materials with specific grain distribution with greater accuracy.

[0154] Figure 2 The figures show the grain size distribution curves for Examples 1, 2, and 4. A comparison reveals that both groups of samples treated with lithium-depleted sintering exhibit a bimodal distribution. The grain size distribution curves for Examples 1 and 2 show sharp peaks, concentrated grain size distribution, and no obvious large particle tailing. In contrast, the sample in Comparative Example 4, which was not treated with lithium-depleted sintering, shows flat peaks, dispersed grain size, and obvious large particle tailing. Comparing Examples 1 and 2, the grain size distribution is more concentrated after the introduction of Ti.

[0155] As can be seen from the results in Table 2, compared with the comparative example, the single-crystal cathode material obtained by the embodiment further improves the roundness of the single-crystal grains by using Ti doping to refine the single-crystal grains on the basis of lithium-poor sintering, and at the same time controls the average number of grains within a certain range by adjusting the crushing intensity, has better electrical performance.

[0156] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0157] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0158] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A positive electrode material, characterized in that, Including the compounds shown in Formula 1: Li 1+a (Ni x Co y Mn z Ti b )M c O 2±d Formula 1 In Equation 1, -0.05 ≤ a ≤ 0.2, 0.5 ≤ x < 1, 0.5 ≤ y < 1, 0.5 ≤ z < 1, 0 ≤ b < 0.01, 0 <c<0.05,0≤d<0.1; The element M includes at least one of B, Mg, Al, Si, P, Co, Sr, Y, Zr, Sb, W, La, and Ce; The cathode material satisfies: 0<S k <1； 2<K<4； 1.60≤B= D 50 / μ≤2.45; 1.0μm < μ < 3.0μm; Among them, S k The skewness coefficient of the grain size sample of the cathode material is obtained using the third-order moment of motion method, K is the kurtosis coefficient of the grain size sample of the cathode material obtained using the fourth-order moment of motion method, B is the average number of grains of the cathode material, and D is the skewness coefficient of the grain size sample of the cathode material. 50 denoted as the median particle size of the cathode material, and μ as the average grain size of the cathode material.

2. The cathode material according to claim 1, characterized in that, At least one of the following conditions must be met: 0<S k <0.4； 2.5<K<3.5； 1.88≤B= D 50 / μ≤2.00; 0<b<0.01。 3. The cathode material according to claim 1, characterized in that, 1.4μm < μ < 2.2μm.

4. The cathode material according to claim 1, characterized in that, Satisfies: 1.28≤B×K 90 ≤3.07, where K 90 K represents the particle size distribution of the cathode material. 90 =(D 90 -D 10 ) / D 50 .

5. The positive electrode material according to claim 4, characterized in that, 1.88≤B×K 90 ≤2.20。 6. The cathode material according to claim 4, characterized in that, The particle size distribution K of the positive electrode material 90 Satisfy: 0.80≤K 90 ≤1.

25.

7. The cathode material according to claim 6, characterized in that, 1.00≤K 90 ≤1.10。 8. The positive electrode material according to claim 1, characterized in that, The ellipticity P of the cathode material satisfies: 0 ≤ P < 0.8, where the ellipticity P is the ratio of the difference between the longest and shortest diagonal lengths of the cross-section of the cathode material particles to its grain size.

9. The cathode material according to claim 8, characterized in that, 0≤P<0.4。 10. The cathode material according to claim 1, characterized in that, The grain size distribution curve of the cathode material includes two peaks and satisfies at least one of the following conditions: The distance between the two peaks is less than 0.6 μm; The proportion of small particle peaks in the two peaks is higher than that of large particle peaks.

11. A method for preparing the cathode material according to any one of claims 1 to 10, characterized in that, include: A nickel-cobalt-manganese precursor is mixed with a first lithium source and optionally a titanium-containing compound to obtain a first mixture; The first mixture is subjected to a first sintering and the resulting first sintering product is subjected to a first crushing to obtain a first process product; The first process product, the second lithium source, and the optional titanium-containing compound are mixed to obtain a second mixture; The second mixture is subjected to a second sintering and the resulting secondary sintering product is subjected to a second crushing to obtain the second process product; The second process product is mixed with the compound containing M to obtain a third mixture; The third mixture is sintered a third time to obtain the cathode material; The sum of the amounts of nickel, cobalt, and manganese elements in the nickel-cobalt-manganese precursor, the ratio of the amount of lithium element in the first lithium source to the amount of lithium element in the second lithium source, is 1:0.2~0.8:0.25~0.

85. The element M is at least one of B, Mg, Al, Si, P, Ti, Co, Sr, Y, Zr, Sb, La, and Ce; The temperature of the first sintering is 600℃~1100℃; The temperature for the second sintering is 800℃~1100℃; The temperature for the third sintering is 300℃~900℃.

12. The method according to claim 11, characterized in that, The first sintering satisfies at least one of the following conditions: The heating time for the first sintering is 2h to 10h; The holding time for the first sintering is 6h to 12h.

13. The method according to claim 11, characterized in that, The first sintering satisfies at least one of the following conditions: The heating time for the first sintering is 6h~8h; The temperature for the first sintering is 700℃~900℃; The holding time for the first sintering is 8h~10h.

14. The method according to claim 11, characterized in that, The second sintering satisfies at least one of the following conditions: The heating time for the second sintering is 2h to 10h; The holding time for the second sintering is 6h to 12h.

15. The method according to claim 14, characterized in that, The second sintering satisfies at least one of the following conditions: The heating time for the second sintering is 6h~8h; The temperature for the second sintering is 900℃~1000℃; The holding time for the second sintering is 8 to 10 hours.

16. The method according to claim 11, characterized in that, The third sintering satisfies at least one of the following conditions: The heating time for the third sintering is 2h to 10h; The holding time for the third sintering is 6h to 12h.

17. The method according to claim 16, characterized in that, The third sintering satisfies at least one of the following conditions: The heating time for the third sintering is 3h~8h; The temperature for the third sintering is 400℃~800℃; The holding time for the third sintering is 8 to 10 hours.

18. The method according to claim 11, characterized in that, At least one of the following conditions must be met: The nickel-cobalt-manganese precursor includes at least one of nickel-cobalt-manganese hydroxide and nickel-cobalt-manganese oxide; The first lithium source and the second lithium source each independently include at least one of lithium carbonate, lithium hydroxide, lithium acetate, and lithium chloride; The titanium-containing compound includes at least one of titanium oxides, hydroxides, carbonates, and phosphates; The M-containing compound includes at least one of the following: oxides, hydroxides, carbonates, and phosphates of element M.

19. A battery, characterized in that, Includes the cathode material according to any one of claims 1 to 10.

20. An electrical appliance, characterized in that, It includes the positive electrode material according to any one of claims 1 to 10 or the battery according to claim 19.

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