Ternary cathode material precursor, preparation method, and use

Abstract

This disclosure discloses a ternary cathode material precursor, a method for preparing it, and its use, and belongs to the technical field of lithium-ion battery cathode materials. The general formula of the ternary cathode material precursor is Ni a Co b M 1-a-b (OH)2, where 0.3 ≤ a < 0.98, 0

Description

[Technical Field]

[0001] This disclosure belongs to the technical field of lithium-ion battery cathode materials, and more specifically relates to ternary cathode material precursors, preparation methods, and uses.

[0002] Cross-references of related applications This application claims priority based on a Chinese application filed with the China Patent Administration on 24 May 2024, application number 202410649899.3, titled "Ternary Cathode Material Precursor, Preparation Method and Use," the entirety of which is incorporated by reference in this disclosure. [Background technology]

[0003] To address the environmental problems caused by automobiles' use of fossil fuels, new energy vehicles are attracting attention because they offer the benefits of using green energy and sustainable development. The rapid development of lithium-ion batteries as a power source for new energy vehicles is driving significant advancements in ternary cathode materials. Ternary cathode materials have the advantages of high specific capacity, reasonable pricing, low toxicity, and relatively abundant resources.

[0004] Ternary cathode materials are generally obtained by mixing nickel-cobalt-manganese hydroxide or nickel-cobalt-aluminum hydroxide, which are ternary cathode material precursors, with a lithium source and then calcining the mixture. The ternary cathode material precursor generally has the appearance of a porous spherical body, and consists of secondary particles formed by primary particles overlapping and bonding with each other. Its porous structure is composed of internal spaces formed when primary particles overlap and bond with each other during aggregation. To increase lithium ion transport efficiency, those skilled in the art generally increase the number of active sites by increasing the specific pore volume and specific surface area. However, in some cases, increasing the specific pore volume or specific surface area can actually decrease lithium ion transport efficiency, affecting the accuracy of performance predictions for ternary cathode materials and making it impossible to obtain ternary cathode materials with relatively good performance.

[0005] In view of this, the present disclosure is provided.

Summary of the Invention

[0006] An object of the present disclosure is to provide a ternary cathode material precursor, a preparation method, and use thereof that can improve the lithium ion transport efficiency of the ternary cathode material.

[0007] The present disclosure is realized as follows.

[0008] In a first aspect, the present disclosure provides a ternary cathode material precursor. The general formula of the ternary cathode material precursor is Ni a Co b M 1-a-b (OH)₂, where 0.3 ≤ a < 0.98, 0 < b < 0.5, 0 < 1 - a - b < 0.5 are satisfied, M is at least one of Mn and Al, the ternary cathode material precursor includes effective pores and ineffective pores, the effective pores refer to pores into which water can enter under standard atmospheric pressure, the ineffective pores refer to pores into which water cannot enter under standard atmospheric pressure, and the effective specific pore volume ratio of the ternary cathode material precursor is 75% - 90%. Here, the effective specific pore volume ratio = V 有効 / V 孔 ×100%, V 有効 refers to the specific pore volume of the effective pores, with the unit of cm 3 / g, V 無効 refers to the specific pore volume of the ineffective pores, with the unit of cm 3 / g, V 孔 = V 有効 + V 無効 .

[0009] In some embodiments, the ternary cathode material precursor has (1) V 孔 being 0.01 cm 3 / g to 0.06 cm 3 / g, and (2) V 有効 = V 総 - V 排 , V 孔 = V 総 - V 材 . Here, V 総 = V材 +V 有効 +V 無効 This refers to the volume of mercury displaced by a ternary cathode material precursor per unit mass when immersed in mercury, and its unit is cm³. 3 / g and V 排 =V 材 +V 無効 This is the volume of water displaced by a ternary cathode material precursor per unit mass when immersed in water, and its unit is cm³. 3 / g and V 材 (3) The V 有効 and V 孔 Each of the measurement processes is carried out at a temperature of 4°C to 80°C, (4) the D50 of the ternary cathode material precursor is 8 μm to 12 μm, and (5) the specific surface area of ​​the ternary cathode material precursor is 6.4 m². 2 / g~7.5m 2 (6) The tap density of the ternary cathode material precursor is 1.9 g / cm³. 3 ~2.3g / cm 3 It is that it satisfies at least one of the characteristics (1) to (6) of the following.

[0010] In some embodiments, the total weight percentage of sodium and sulfur elements in the ternary cathode material precursor is less than 0.21 wt%, and / or the weight percentage of sodium in the ternary cathode material precursor is less than 0.03 wt%, and / or the weight percentage of sulfur in the ternary cathode material precursor is less than 0.21 wt%.

[0011] In a second embodiment, the present disclosure provides a method for preparing a ternary cathode material precursor according to the above embodiment. The preparation method includes a seed crystal preparation step of preparing nanoseed crystals of a ternary cathode material precursor using a coprecipitation method under supergravity conditions, and a seed crystal growth step of growing the nanoseed crystals to obtain the ternary cathode material precursor.

[0012] In some embodiments, the seed crystal preparation step includes the steps of: placing ammonia water with a pH of 10 to 11 as a reaction base solution into a rotating bed reactor; adding nickel-cobalt M mixed salt solution and a mixed aqueous solution containing a precipitant and a complexing agent to the two liquid storage tanks of the rotating bed in parallel to the rotating bed reactor; maintaining the pH value at 10.5 to 11.5; stopping the material supply when the precipitate reaches a first predetermined particle size; stopping the rotation of the rotating bed; allowing it to stand and age to obtain a first reaction solution containing seed crystals; and the seed crystal preparation step is characterized in that: A. The first predetermined particle size D50 is 200 nm to 500 nm; B. In the mixed aqueous solution, the concentration of the precipitant is 3 mol / L to 5 mol / L and the concentration of the complexing agent is 1.5 mol / L to 2.5 mol / L; and C. The rotation speed of the rotating bed is The device further satisfies at least one of the following characteristics: D. The speed is 1000 rpm to 1500 rpm; E. The salt in the nickel-cobalt-M mixed salt solution is one of nitrate, hydrochloride, or sulfate; F. The molar ratio of nickel-cobalt-M is 35 to 98:1 to 35:1 to 35; G. The total concentration of the three elements nickel, cobalt, and M in the nickel-cobalt-M mixed salt solution is 1.5 mol / L to 2.5 mol / L; G. The flow rate of the nickel-cobalt-M mixed salt solution is 50 mL / min to 100 mL / min; H. The precipitating agent is potassium hydroxide or sodium hydroxide; and I. The complexing agent is one of ammonia water, ammonium nitrate, ammonium sulfate, and ammonium chloride.

[0013] In some embodiments, the seed crystal growth step includes the steps of: adjusting the pH of the first reaction solution containing the seed crystal to 9.5-10.5; adding the nickel-cobalt M mixed salt solution, an aqueous solution of the crystal structure modifier, and a mixed aqueous solution containing a precipitant and a complexing agent to the first reaction solution containing the seed crystal to obtain a second reaction solution; maintaining the pH of the second reaction solution at 9.5-10.5; adjusting the ammonia concentration to 0.4 mol / L-0.8 mol / L; stopping the material supply when the precipitate reaches a second predetermined particle size; allowing it to stand and age to obtain a slurry containing the ternary cathode material precursor; and the seed crystal growth step is further characterized in that: a. the crystal structure modifier is an anionic surfactant; and b The present invention further satisfies at least one of the following features: a. The concentration of the aqueous solution of the crystal structure modifier is 0.01 mol / L to 0.05 mol / L; c. The flow rate of the nickel-cobalt M mixed salt solution is 0.2 mL / min to 0.5 mL / min; d. The flow rate of the aqueous solution of the crystal structure modifier is 0.2 mL / min to 0.5 mL / min; e. The second predetermined particle size D50 is 8 μm to 12 μm; f. Solid-liquid separation is performed on the slurry containing the ternary cathode material precursor, and the solid phase is washed using an alkaline solution and pure water in sequence, followed by drying, sieving and demagnetization to obtain the ternary cathode material precursor.

[0014] In some embodiments, the crystal structure modifier is sodium polypropylene and sodium ligninsulfonate, and / or the alkaline solution is a sodium hydroxide solution or a potassium hydroxide solution with a concentration of 50 g / L to 70 g / L and a temperature of 50°C to 80°C.

[0015] In a third embodiment, the present disclosure provides a ternary cathode material. The ternary cathode material is a ternary cathode material obtained by mixing a ternary cathode material precursor prepared according to the above embodiment or by a preparation method according to any one of the above embodiments with a lithium source and firing, wherein the ternary cathode material has the following characteristics: g. The effective specific pore volume ratio of the ternary cathode material is 75% to 90%, and h. The specific surface area of ​​the ternary cathode material is 0.4 m². 2 / g~0.7m 2 i. The tap density of the ternary cathode material is 2.6 g / cm³. 3 ~2.9g / cm 3 The condition is met, and furthermore, at least one of the characteristics g to i of the condition is satisfied.

[0016] In some embodiments, the initial discharge ratio capacity at 0.1C corresponding to the ternary cathode material is 192 mAh / g to 208 mAh / g, and / or the initial discharge ratio capacity at 1C corresponding to the ternary cathode material is 167 mAh / g to 190 mAh / g, and / or the capacity retention rate after 100 cycles at 1C corresponding to the ternary cathode material is 85% to 97%, and / or the initial discharge ratio capacity at 5C corresponding to the ternary cathode material is 142 mAh / g to 165 mAh / g.

[0017] In a fourth embodiment, the present disclosure provides a method for preparing a ternary cathode material. The method for preparing a ternary cathode material involves mixing a ternary cathode material precursor prepared according to any one of the above embodiments, or a ternary cathode material precursor prepared by the preparation method according to any one of the above embodiments, with a lithium source and firing to obtain the ternary cathode material.

[0018] In some embodiments, the firing temperature is 400°C to 800°C, and the firing time is 15 to 20 hours.

[0019] In some embodiments, the firing includes a single-stage firing and a double-stage firing, where the single-stage firing is at a temperature of 400°C to 600°C for a duration of 4 to 6 hours, and the double-stage firing is at a temperature of 750°C to 800°C for a duration of 10 to 14 hours.

[0020] In some embodiments, the heating rate during the firing process is 1.5°C / min to 2.5°C / min.

[0021] In a fifth embodiment, the disclosure provides a positive electrode plate comprising a positive electrode material according to the above embodiment.

[0022] In a sixth embodiment, the present disclosure provides a battery cell, the battery cell including a positive electrode plate according to the above embodiment.

[0023] In a seventh embodiment, the present disclosure provides a lithium-ion battery, the lithium-ion battery including a positive electrode plate according to the above embodiment.

[0024] In an eighth embodiment, the present disclosure provides an electrical device, which includes a lithium-ion battery according to the above embodiment.

[0025] This disclosure has the following beneficial effects:

[0026] The ternary cathode material precursor according to this disclosure has an effective specific pore volume ratio of 75% to 90%, which can contribute to reducing the amount of residual impurities in the precursor. When a cathode material is prepared using this precursor, lithium can penetrate into the interior of the material, and a cathode material with a perfect crystal structure and uniform elemental distribution can be formed. When a cathode material prepared using this precursor is used in a lithium-ion battery, the lithium-ion battery has relatively excellent cycle stability and rate performance.

[0027] To more clearly explain the technical concepts of the embodiments of this disclosure, the drawings used in the embodiments are briefly described below. The drawings described are merely illustrative of some embodiments of this disclosure and do not limit the scope. Those skilled in the art can obtain other relevant drawings based on these drawings without inventive ability. [Brief explanation of the drawing]

[0028] [Figure 1] The images show the appearance or cross-section of the material prepared in Example 1 (A: SEM image of precipitate before aging when preparing seed crystals, B: SEM image of seed crystals, C: SEM image of ternary cathode material precursor, D: cross-sectional image of ternary cathode material precursor, E: SEM image of ternary cathode material, F: cross-sectional image of ternary cathode material).

[0029] [Figure 2] These are cross-sectional images of the ternary cathode material after 100 cycles (A: ternary cathode material prepared in Example 1, B: ternary cathode material prepared in Comparative Example 4).

[0030] [Figure 3] This is a cross-sectional image of the ternary cathode material precursor prepared in Comparative Example 1.

[0031] [Figure 4] This is an SEM image of the ternary cathode material precursor prepared in Comparative Example 5. [Modes for carrying out the invention]

[0032] To more clearly explain the purpose, technical proposals, and advantages of the embodiments of this disclosure, the technical proposals in the embodiments of this disclosure will be described clearly and completely below. Where specific conditions are not specified in the embodiments, it is possible to perform the experiments under conventional conditions or conditions recommended by the manufacturer. For reagents or instruments where the manufacturer is not specified, commercially available conventional products can be used.

[0033] In addition, the term "and / or" used in this specification represents the relationship of related objects and indicates the existence of three types of relationships. For example, A and / or B represents three types of relationships: only A exists, both A and B exist, and only B exists.

[0034] In a first aspect, the present disclosure provides a ternary cathode material precursor. The general formula of the ternary cathode material precursor is Ni a Co b M 1-a-b (OH)2, provided that 0.3 ≤ a < 0.98, 0 < b < 0.5, 0 < 1 - a - b < 0.5 are satisfied, M is at least one of Mn and Al, the ternary cathode material precursor includes effective pores and ineffective pores, the effective pores refer to pores into which water can enter, the ineffective pores refer to pores into which water cannot enter, and the effective specific pore volume ratio of the ternary cathode material precursor is 75% - 90%.

[0035] Here, the effective specific pore volume ratio = V 有効 / V 孔 ×100%, where V 有効 refers to the specific pore volume of the effective pores, with the unit of cm 3 / g, V 無効 refers to the specific pore volume of the ineffective pores, with the unit of cm 3 / g, and V 孔 =V 有効 +V 無効 .

[0036] The ternary cathode material precursor consists of secondary particles formed by the overlapping and bonding of primary particles. Its porous structure is composed of internal spaces formed when primary particles overlap and bond together during aggregation. Some of these internal spaces are closed, forming pores, and these internal pores are also present in the cathode material after lithium is added and sintered. While these pores can reduce internal stress generated during the charging and discharging process of lithium batteries and suppress the occurrence of micro-cracks, they can also lead to the closure of active sites, preventing the penetration and reaction of the lithium source, reducing the diffusion rate of lithium ions, decreasing specific capacity, and causing problems such as the retention of impurity elements. Therefore, it is necessary to keep the size of the pores within an appropriate range.

[0037] Furthermore, to increase lithium ion transport efficiency by increasing the contact area between the active substance and the electrolyte, conventional techniques have employed methods to increase the specific surface area of ​​the cathode material. However, currently, specific surface area is generally measured using N2 adsorption / desorption tests, and this index does not fully reflect the degree of contact between the material and the liquid. This is because the wettability of the material to gaseous N2 and liquid (water, electrolyte, etc.) differs, resulting in a phenomenon where some materials have a large specific surface area but conversely exhibit relatively low lithium ion transport efficiency. For this reason, conventional techniques cannot reliably obtain ternary cathode materials or ternary cathode material precursors with relatively superior performance, even when combining the two parameters of specific surface area and specific pore volume.

[0038] In the embodiments of this disclosure, pores in the ternary cathode material precursor are classified, where effective pores refer to pores into which water can enter, and ineffective pores refer to pores into which water cannot enter. Ineffective pores mainly include closed pores and micropores, where the pore diameter is too small for water or electrolyte to enter. By classifying effective pores and ineffective pores, pores that can come into contact with the electrolyte and contribute to improving the diffusion rate of lithium ions (i.e., effective pores) and pores that cannot come into contact with the electrolyte but can release internal stress generated during the charging and discharging process of the lithium battery (i.e., ineffective pores) are classified.

[0039] In the embodiments of this disclosure, the effective specific pore volume fraction may be 75%, 77%, 79%, 81%, 83%, 85%, 87%, 89%, 90%, or any other value in the range of 75% to 90%. If the effective specific pore volume fraction of the ternary cathode material precursor is too large, it indicates that the interior of the material is denser or the external pore diameter of the material is larger. On the other hand, if the interior is dense, it is unfavorable for the process of lithium addition and high-temperature solid-state sintering, as it is difficult for Li to penetrate the interior, the specific capacity decreases, and during use, cracks occur inside the material because there is no space as a stress dissipation point, resulting in reduced cycle performance. On the other hand, if the external pore diameter is too large, the specific surface area of ​​the resulting cathode material is too large, increasing interfacial reactions and reducing cycle performance. If the effective specific pore volume fraction of the ternary cathode material precursor is too small, it indicates that the interior of the material is more sparse or the external pore diameter is smaller. On the other hand, because the interior is sparse, there are many closed pores inside the cathode material, the tap density decreases, the specific capacity decreases, water cannot penetrate the interior during washing, and a large amount of residual sodium and sulfur elements remain, impairing electrical performance. Conversely, if the external pore diameter is too small, the specific surface area of ​​the resulting cathode material is too small, reducing the contact area between lithium ions and the electrolyte, and degrading rate performance.

[0040] Furthermore, when the effective specific pore volume ratio is 75% to 90%, it can contribute to reducing the amount of residual impurities in the precursor. When a cathode material is prepared using this precursor, lithium can penetrate into the interior of the material, making it possible to form a cathode material with a perfect crystal structure and uniform elemental distribution. When a cathode material prepared using this precursor is used in a lithium-ion battery, the lithium-ion battery will have relatively good cycle stability and rate performance.

[0041] As described above, the effective specific pore volume ratio of the ternary cathode material precursor prepared in the embodiments of this disclosure is 75% to 90%, which contributes to reducing the amount of residual impurities in the precursor. When a cathode material is prepared using this precursor, lithium can penetrate into the interior of the material, forming a cathode material with a perfect crystal structure and uniform elemental distribution. This contributes to improving the cycle stability and lithium ion transport efficiency of the cathode material prepared using this cathode material.

[0042] In some embodiments, in the ternary cathode material precursor, V 孔 is 0.01 cm 3 / g~0.06cm 3 It is / g, specifically 0.01cm 3 / g, 0.02cm 3 / g, 0.03cm 3 / g, 0.04cm 3 / g, 0.05cm 3 / g, 0.06cm 3 / g or 0.01cm 3 / g~0.06cm 3 V can be any other value within the range of / g. 孔 Increasing V can help lithium ions penetrate the interior of the precursor during the process of lithium addition and high-temperature solid-phase sintering, but V 孔 If this becomes excessive, some of the pore structure remains in the ternary cathode material, impairing the cycle performance of the ternary cathode material.

[0043] In some embodiments, in the ternary cathode material precursor, V 有効 =V 総 -V 排 And here, V 総 =V 材 +V 有効 +V 無効 This is the volume of mercury displaced by a ternary cathode material precursor per unit mass when immersed in mercury, and its unit is cm³. 3 / g and V 排 =V 材 +V 無効 This is the volume of water displaced by a ternary cathode material precursor per unit mass when immersed in water, and its unit is cm³.3 is / g, and V 材 is the reciprocal of the density of the ternary cathode material precursor.

[0044] In an embodiment of the present disclosure, V 総 and V 排 are measured to determine the specific pore volume of the effective pores.

[0045] Specifically, V 総 is measured by the following method. Measure the mercury liquid level height in a container filled with mercury and record it as H0. Place the ternary cathode material precursor in the container filled with mercury. Since the density of the ternary cathode material precursor is smaller than that of mercury, the material floats on the liquid surface. Use a piston with a volume of V' to push the material floating on the liquid surface below the liquid surface at a speed less than 50 mm / min. After the liquid surface stops, measure the liquid level height and record it as H1. Based on H0, H1, and other shape parameters of the container, V0 and V1, which are the volumes corresponding to the liquid level heights H0 and H1 respectively, can be calculated. Therefore, V 総 = V1 - V0 - V' can be used to calculate V 総 As a measurement principle, since the wettability of the ternary cathode material precursor according to the present disclosure with respect to mercury is relatively low, capillary phenomenon does not occur, and mercury, due to its relatively large surface tension, cannot enter pores smaller than the micro size without external pressure. Therefore, by this method, a relatively accurate apparent volume can be measured. Also, the V 総 of the material may be measured using an imaging method such as three-dimensional imaging.

[0046] V 排 The measurement method of V 総 can be referred to, and the liquid can be replaced with water, and V 排 may be measured in other equivalent ways.

[0047] In some embodiments, in the ternary cathode material precursor, V 孔 = V 総 - V 材 and on the premise that V 総 is measured, only the density of the material needs to be measured to obtain V孔 can be calculated and contribute to the simplification of the measurement steps.

[0048] In some embodiments, in the ternary cathode material precursor, the V 有効 and V 孔 The respective measurement processes of are carried out at a temperature of 4°C to 80°C and standard atmospheric pressure. Since the wetting situation of the electrolyte with respect to the cathode material can be simulated relatively accurately when the battery is operating, in the embodiments of the present disclosure, the temperature and pressure used in the measurement processes of V 有効 and V 孔 are within the operating temperature range of the battery. For example, the temperature is 4°C to 80°C, the pressure is standard atmospheric pressure, and the water used can be deionized water, sodium hydroxide solution, potassium hydroxide solution, ammonia water, etc. In order to make the material and the liquid contact sufficiently, operations such as stirring, ultrasonic, and vibration can be performed on the mixture of the ternary cathode material precursor and the liquid, but pressure should not be applied. Since it takes a certain amount of time for the liquid to penetrate into the ternary cathode material precursor, when reading the volume of the water or mercury displaced by the ternary cathode material precursor, read it after the volume has stopped changing.

[0049] In some embodiments, the D50 of the ternary cathode material precursor is 8 μm to 12 μm, specifically, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm or any other value within the range of 8 μm to 12 μm. The larger the particle size of the ternary cathode material precursor, the larger the particle size of the ternary cathode material prepared thereby. The larger the particle size of the ternary cathode material, the longer the path through which lithium ions pass when inserting or desorbing, which is disadvantageous for improving the capacity.

[0050] In some embodiments, the specific surface area of the ternary cathode material precursor is 6.4 m 2 / g to 7.5 m 2 / g, specifically, 6.4 m 2 / g, 6.5 m 2 / g, 6.7 m 2 / g, 6.9 m 2 / g, 7.1 m2 / g, 7.3m 2 / g, 7.5m 2 / g or 6.5m 2 / g~7.5m 2 It can be any other value within the range of / g. Improving the specific surface area of ​​the ternary cathode material precursor can contribute to improving the specific surface area of ​​the ternary cathode material, and therefore to improving the lithium ion transport efficiency. However, if the specific surface area is too large, the contact area between the ternary cathode material prepared using the ternary cathode material precursor and the electrolyte may become too large, potentially reducing the cycle performance of the ternary cathode material.

[0051] In some embodiments, the tap density of the ternary cathode material precursor is 1.9 g / cm³. 3 ~2.3g / cm 3 Specifically, 1.9 g / cm³ 3 2.0 g / cm³ 3 , 2.1 g / cm³ 3 , 2.2 g / cm³ 3 2.3 g / cm³ 3 Or 1.9 g / cm³ 3 ~2.3g / cm 3 It can be any other value within the range. The tap density of the ternary cathode material precursor is related to the tap density of the ternary material; the higher the tap density of the ternary cathode material precursor, the higher the tap density of the ternary material under equivalent conditions, and therefore the higher the energy density.

[0052] In some embodiments, the total weight percentage of sodium and sulfur elements in the ternary cathode material precursor is less than 0.21 wt%.

[0053] In some embodiments, the weight percentage of the sodium element in the ternary cathode material precursor is less than 0.03 wt%.

[0054] In some embodiments, the weight percentage of sulfur element in the ternary cathode material precursor is less than 0.21 wt%.

[0055] Embodiments of this disclosure provide a method for preparing a ternary cathode material precursor according to the above embodiments. The preparation method includes a seed crystal preparation step of preparing nanoseed crystals of a ternary cathode material precursor using a coprecipitation method under supergravity conditions, and a seed crystal growth step of growing the nanoseed crystals to obtain the ternary cathode material precursor.

[0056] In the embodiments of this disclosure, nano-seed crystals of ternary cathode material precursors are prepared using a coprecipitation method under supergravity conditions. The basic principle is to generate a stable and controllable strong centrifugal force field using a high-speed rotating annular rotor. Under supergravity conditions, molecular diffusion between molecules of different sizes and interphase mass transfer processes are generally much faster than in a gravitational field. The material flows and mixes in a supergravity field hundreds to thousands of times greater than Earth's gravity. Under the action of enormous shear forces, the liquid is torn into nano-sized droplets, threads, and films, creating huge phase interfaces. The mass transfer rate is improved by 1 to 3 orders of magnitude compared to conventional tower-type devices, and microscopic mixing and mass transfer processes are greatly enhanced. The reaction is then carried out in a supergravity reactor, and because the liquid residence time is extremely short, an extremely large supersaturated interface is created, resulting in extremely small and uniform product particle size.

[0057] By preparing morphologically uniform nanoparticles using the supergravity coprecipitation method and then aging them, the crystal grains are further grown or partially aggregated. Because the particles are small, uniform in size, and nearly spherical, the internal structure of the crystal nuclei obtained by aging is relatively dense, which reduces the ineffective pore volume. Furthermore, by performing secondary growth under non-supergravity conditions using these as crystal nuclei, a precursor material is formed in which the crystals formed on the surface of the crystal nuclei are relatively sparse, with a dense interior and a sparse exterior, thereby obtaining the target effective pore volume ratio.

[0058] In some embodiments, the seed crystal preparation step includes the following steps: an aqueous ammonia solution with a pH of 10-11 is placed in a rotating bed reactor as the reaction base solution; a nickel-cobalt M mixed salt solution and a mixed aqueous solution containing a precipitant and a complexing agent are added in parallel to the rotating bed reactor to two liquid storage tanks of the rotating bed, respectively, while maintaining the pH value at 10.5-11.5, which may be 10.5, 11, 11.5, or any other value in the range of 10.5-11.5; when the precipitate reaches a first predetermined particle size, the material supply is stopped, the rotation of the rotating bed is stopped, and after standing and aging, a first reaction solution containing seed crystals is obtained.

[0059] In embodiments of this disclosure, the pH of the reaction base solution may be 10, 10.5, 11, or any other value in the range of 10 to 11. A rotating bed with a helical channel can be selected as the rotating bed reactor. If the seed crystal structure prepared in embodiments of this disclosure is relatively dense, and if the seed crystal structure is dense and the particle size is small, it can contribute to improving the effective specific pore volume fraction of the precursor.

[0060] In some embodiments, the first predetermined particle size D50 is 200 nm to 500 nm, and specifically, it may be 200 nm, 300 nm, 400 nm, 500 nm, or any other value in the range of 200 nm to 500 nm. If the particle size of the seed crystal is relatively small, it can contribute to improving the effective specific pore volume fraction of the precursor.

[0061] In some embodiments, the concentration of the precipitant in the mixed aqueous solution is 3 mol / L to 5 mol / L, specifically 3 mol / L, 4 mol / L, 5 mol / L, or any other value in the range of 3 mol / L to 5 mol / L. The concentration of the complexing agent is 1.5 mol / L to 2.5 mol / L, specifically 1.5 mol / L, 2 mol / L, 2.5 mol / L, or any other value in the range of 1.5 mol / L to 2.5 mol / L. The precipitant can contribute to improving the precipitation rate, and the complexing agent, such as aqueous ammonia, can contribute to controlling the precipitation rate and obtaining seed crystals with relatively good sphericity.

[0062] In some embodiments, the rotation speed of the rotating bed is 1000 rpm to 1500 rpm, and specifically, it may be 1000 rpm, 1100 rpm, 1200 rpm, 1300 rpm, 1400 rpm, 1500 rpm, or any other value in the range of 1000 rpm to 1500 rpm. Under equivalent conditions, a faster rotation speed of the rotating bed can contribute to reducing the grain size of the seed crystal and improving the uniformity of the seed crystal grain size distribution. If the rotation speed of the rotating bed is too fast, the structure of the resulting seed crystal will become too dense, resulting in an excessively high effective pore volume ratio.

[0063] In some embodiments, the salt in the nickel-cobalt M mixed salt solution is one of nitrates, hydrochlorides, or sulfates, which have low raw material costs and are easy to remove anions from.

[0064] In some embodiments, the molar ratio of nickel-cobalt M is 35-98:1-35:1-35, which can contribute to obtaining a ternary cathode material precursor having the required composition.

[0065] In some embodiments, the total concentration of the three elements nickel, cobalt, and M in the nickel-cobalt-M mixed salt solution is 1.5 mol / L to 2.5 mol / L, and specifically, it can be 1.5 mol / L, 2 mol / L, 2.5 mol / L, or any other value in the range of 1.5 mol / L to 2.5 mol / L. This helps to control the pore structure of the ternary cathode material precursor by keeping the precipitation rate within a reasonable range.

[0066] In some embodiments, the flow rate of the nickel-cobalt M mixed salt solution is 50 mL / min to 100 mL / min, and specifically can be 50 mL / min, 70 mL / min, 90 mL / min, 100 mL / min, or any other value in the range of 50 mL / min to 100 mL / min. This helps to control the pore structure of the ternary cathode material precursor by keeping the precipitation rate within a reasonable range.

[0067] In some embodiments, the precipitating agent is potassium hydroxide or sodium hydroxide, which has low raw material costs and easily removes cations.

[0068] In some embodiments, the complexing agent is one of ammonia water, ammonium nitrate, ammonium sulfate, and ammonium chloride, which have low raw material costs and easily remove anions.

[0069] In some embodiments, the seed crystal growth step includes the following steps: The pH of the first reaction solution containing the seed crystal is set to 9.5-10.5, specifically to 9.5, 10, 10.5, or any other value in the range of 9.5-10.5; and the nickel-cobalt M mixed salt solution, an aqueous solution of the crystal structure modifier, and a mixed aqueous solution containing a precipitant and a complexing agent are added to the first reaction solution containing the seed crystal to obtain a second reaction solution; the pH of the second reaction solution is maintained at 9.5-10.5, the ammonia concentration is set to 0.4 mol / L-0.8 mol / L; when the precipitate reaches a second predetermined particle size, the material supply is stopped, and after standing and aging, a slurry containing the ternary cathode material precursor is obtained.

[0070] By adding a crystal structure modifier and performing secondary growth, it is possible to contribute to the formation of more sparse, flake-like crystals on the surface of the seed crystal, thereby contributing to the formation of a precursor material that is dense inside and sparse outside, and thus obtaining the target effective pore volume ratio.

[0071] In some embodiments, the crystal structure modifier is an anionic surfactant, and the anionic surfactant can electrostatically act on the positively charged active crystal surface of the precursor crystal, thereby suppressing the growth of the crystal surface and forming a flake crystal.

[0072] In some embodiments, the concentration of the aqueous solution of the crystal structure modifier is 0.01 mol / L to 0.05 mol / L, and specifically, it may be 0.01 mol / L, 0.02 mol / L, 0.03 mol / L, 0.04 mol / L, 0.05 mol / L, or any other value in the range of 0.01 mol / L to 0.05 mol / L. Under equivalent conditions, the higher the concentration of the crystal structure modifier, the higher the concentration of the crystal structure modifier in the reaction solution, and the resulting ternary cathode material precursor has a more sparse exterior, a higher effective specific pore volume fraction, and a lower amount of residual impurity elements inside the material.

[0073] In some embodiments, during the seed crystal growth step, the flow rate of the nickel-cobalt-M mixed salt solution is 0.2 mL / min to 0.5 mL / min, and specifically, it may be 0.2 mL / min, 0.3 mL / min, 0.4 mL / min, 0.5 mL / min, or any other value in the range of 0.2 mL / min to 0.5 mL / min. By adjusting the flow rate of the nickel-cobalt-M mixed salt solution, it is possible to control the pore structure of the ternary cathode material precursor by keeping the precipitation rate within a reasonable range.

[0074] In some embodiments, during the seed crystal growth step, the flow rate of the aqueous solution of the crystal structure modifier is 0.2 mL / min to 0.5 mL / min, and specifically, it may be 0.2 mL / min, 0.3 mL / min, 0.4 mL / min, 0.5 mL / min, or any other value in the range of 0.2 mL / min to 0.5 mL / min. Under equivalent conditions, a higher flow rate of the crystal structure modifier results in a higher concentration of the crystal structure modifier in the reaction solution, and the resulting ternary cathode material precursor has a more sparse exterior, a higher effective specific pore volume fraction, and a lower amount of residual impurity elements inside the material.

[0075] In some embodiments, the second predetermined particle size D50 is 8 μm to 12 μm, i.e., the particle size of the ternary cathode material precursor.

[0076] In some embodiments, the process further includes solid-liquid separation of the slurry containing the ternary cathode material precursor, washing the solid phase using an alkaline solution and pure water in sequence, drying, sieving, and demagnetizing to obtain the ternary cathode material precursor. When washing the ternary cathode material precursor with an alkaline solution and pure water, impurities such as sodium, potassium, sulfur, nitrogen, and chlorine introduced into the material along with the nickel-cobalt M mixed salt solution, precipitant, and complexing agent can be removed.

[0077] In some embodiments, the crystal structure modifiers are sodium polypropyleneate and sodium ligninsulfonate. Compared to low molecular weight anionic surfactants, polyanionic surfactants such as sodium polypropyleneate and sodium ligninsulfonate can improve the steric hindrance effect, thereby enabling the formation of more sparsely spaced flake crystals on the surface and achieving a relatively large effective specific pore volume.

[0078] In some embodiments, the alkaline solution is a sodium hydroxide solution or a potassium hydroxide solution with a concentration of 50 g / L to 70 g / L and a temperature of 50°C to 80°C. The purpose of alkaline washing is to remove sulfur. Before alkaline washing, sulfate ions are present in the solid phase in the form of a double salt, and alkaline washing uses hydroxide ions to replace the sulfate ions, preventing the loss of Ni that would occur by washing directly with water.

[0079] The specific alkaline solution can be selected based on the type of impurities in the ternary cathode material precursor. If sodium is present as an impurity, sodium hydroxide can be selected as the alkaline solution; if potassium is present as an impurity, potassium hydroxide can be selected as the alkaline solution. Increasing the temperature appropriately can contribute to the removal of impurities.

[0080] This disclosure provides a ternary cathode material. The ternary cathode material is obtained by mixing a ternary cathode material precursor prepared according to the above embodiment or by the preparation method according to any one of the above embodiments with a lithium source and firing.

[0081] In some embodiments, the effective specific pore volume ratio of the ternary cathode material is 75% to 90%, and specifically can be 75%, 77%, 79%, 81%, 83%, 85%, 87%, 89%, 90%, or any other value in the range of 75% to 90%. If the effective specific pore volume ratio is too high, it may lead to a decrease in cycle performance, and if it is too low, it is detrimental to improving specific capacity and rate performance. When the ratio of the specific pore volume of effective pores to the total specific pore volume, i.e., the effective specific pore volume ratio, is 75% to 90%, the cathode material can improve both lithium ion transport efficiency and cycle performance.

[0082] In some embodiments, the specific surface area of ​​the ternary cathode material is 0.4 m². 2 / g~0.7m 2 / g, specifically 0.4m 2 / g, 0.5m 2 / g, 0.6m 2 / g, 0.7m 2 / g or 0.4m 2 / g~0.7m 2 It can be any other value within the range of / g. While an improved specific surface area can contribute to improved lithium ion transport efficiency, if the specific surface area becomes too large, the contact area between the ternary cathode material and the electrolyte may become too large, potentially reducing cycle performance.

[0083] In some embodiments, the tap density of the ternary cathode material is 2.6 g / cm³. 3 ~2.9g / cm 3 Specifically, 2.6 g / cm³ 3 2.7 g / cm³ 3 2.8 g / cm³ 3 2.9 g / cm³ 3 Or 2.6 g / cm³ 3~2.9g / cm 3 It can be any other value within the range. The higher the tap density of the ternary cathode material, the higher the energy density, and if the tap density of the ternary cathode material is too high, the specific pore volume decreases accordingly, making lithium ion movement more difficult.

[0084] In some embodiments, the initial discharge ratio capacity at 0.1C corresponding to the ternary cathode material is 192 mAh / g to 208 mAh / g, and / or the initial discharge ratio capacity at 1C corresponding to the ternary cathode material is 167 mAh / g to 190 mAh / g, and / or the capacity retention rate after 100 cycles at 1C corresponding to the ternary cathode material is 85% to 97%, and / or the initial discharge ratio capacity at 5C corresponding to the ternary cathode material is 142 mAh / g to 165 mAh / g.

[0085] This disclosure provides a method for preparing a ternary cathode material. The ternary cathode material is obtained by mixing a ternary cathode material precursor prepared according to any one of the above embodiments, or a ternary cathode material precursor prepared by the preparation method according to any one of the above embodiments, with a lithium source and firing.

[0086] In some embodiments, the firing temperature is 400°C to 800°C, and specifically can be 400°C, 500°C, 600°C, 700°C, 800°C, or any other value in the range of 400°C to 800°C. The firing time is 15 hours to 20 hours, and specifically can be 15 hours, 16 hours, 17 hours, 18 hours, 19 hours, 20 hours, or any other value in the range of 15 hours to 20 hours.

[0087] In some embodiments, the firing includes single-stage firing and double-stage firing. In single-stage firing, the temperature is 400°C to 600°C, for example, 400°C, 500°C, 600°C, etc., and the time is 4 to 6 hours, for example, 4 hours, 5 hours, 6 hours, etc. In double-stage firing, the temperature is 750°C to 800°C, for example, 750°C, 760°C, 770°C, 780°C, 790°C, 800°C, etc., and the time is 10 to 14 hours, for example, 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, etc.

[0088] In some embodiments, the heating rate during the firing process is 1.5°C / min to 2.5°C / min, for example, 1.5°C / min, 2°C / min, 2.5°C / min, etc.

[0089] This disclosure provides a positive electrode plate, which includes a positive electrode material according to the embodiments described above.

[0090] In the positive electrode plate according to this disclosure, the positive electrode material layer generally comprises the above-mentioned positive electrode material, binder, and conductive agent, and is generally formed by coating a positive electrode slurry, followed by drying and cold rolling. The positive electrode slurry is generally formed by dispersing the above-mentioned positive electrode material, conductive agent, binder, etc., in a solvent and stirring it uniformly. The solvent may be N-methylpyrrolidone (NMP).

[0091] In several selectable embodiments, the cathode material layer contains 70 wt% to 97 wt% of the cathode material relative to the total weight of the cathode material layer. Optionally, the percentage of the cathode material by weight in the cathode material layer is 85% to 97%, 90% to 97%, or 95% to 97%. By controlling the percentage of cathode material in the cathode material layer, the energy density and cycle life of the lithium-ion battery can be further improved.

[0092] In some embodiments, the binder for the positive electrode material layer includes one or more of the following: polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), a ternary copolymer of vinylidene fluoride-tetrafluoroethylene-propylene, a ternary copolymer of vinylidene fluoride-hexafluoropropene-tetrafluoroethylene, a copolymer of tetrafluoroethylene-hexafluoropropene, and modified polymers thereof.

[0093] The conductive agent can improve the electronic conductivity of the positive electrode material layer. In several selectable embodiments, the positive electrode material layer contains 2 wt% to 20 wt% of the conductive agent relative to the total weight of the positive electrode material layer. Optionally, the weight percentage of the conductive agent in the positive electrode material layer is 2% to 10%, or 2% to 5%.

[0094] In some embodiments, the conductive agent of the cathode material layer includes one or more of the following: superconducting carbon, carbon black (e.g., SuperP, acetylene black, Ketjen black), carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0095] The composition or parameters of each positive electrode material layer relating to this disclosure all refer to the composition or parameter range of a film layer on one side of a positive electrode current collector. If the positive electrode material layer is provided on two surfaces, the front and back, of a positive electrode current collector, it is deemed to fall within the scope of protection of this disclosure if the composition or parameters of the positive electrode material layer on any one of those surfaces satisfy this disclosure.

[0096] This disclosure provides a lithium-ion battery, which includes a positive electrode plate according to the above embodiment, and further includes a negative electrode plate, an electrolyte, and a separator.

[0097] [negative electrode plate] The negative electrode plate according to this disclosure includes a negative electrode current collector and a negative electrode film layer provided on at least one surface of the negative electrode current collector.

[0098] For example, a negative electrode current collector has two surfaces that form a front and back in its thickness direction, and the negative electrode film layer is provided on one or both of the two front and back surfaces of the negative electrode current collector.

[0099] The negative electrode current collector uses a material with excellent conductivity and mechanical strength, and performs its function of conducting and collecting current. In some embodiments, copper foil can be used as the negative electrode current collector.

[0100] In the negative electrode plate according to this disclosure, the negative electrode film layer generally comprises a negative electrode active material, a binder, a conductive agent, and other optional auxiliary agents, and is generally formed by coating a negative electrode slurry onto a negative electrode current collector, followed by drying and cold rolling. The negative electrode slurry is generally prepared by dispersing negative electrode and positive electrode materials, a conductive agent, a binder, and other optional auxiliary agents in a solvent and stirring uniformly. The solvent may be N-methylpyrrolidone (NMP) or deionized water.

[0101] In some embodiments, the negative electrode active material includes one or more of the following: artificial graphite, natural graphite, silicon-based materials, and tin-based materials. Optionally, the negative electrode active material includes at least one of artificial graphite and natural graphite. Optionally, the negative electrode active material includes artificial graphite.

[0102] In some embodiments, the conductive agent includes one or more of the following: superconducting carbon, carbon black (e.g., SuperP, acetylene black, Ketjen black, etc.), carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0103] In some embodiments, the binder comprises one or more of the following: styrene-butadiene rubber (SBR), aqueous acrylic resin, polyvinyl alcohol (PVA), sodium alginate (SA), and carboxymethyl chitosan (CMCS).

[0104] In some embodiments, other optional additives may include, for example, thickeners (e.g., sodium carboxymethylcellulose (CMC-Na)), PTC thermistor materials, and so on.

[0105] [Electrolyte] The electrolyte plays a role in conducting ions between the positive and negative electrodes. The type of electrolyte is not specifically limited in this disclosure and can be selected according to the needs. For example, the electrolyte may be an electrolyte solution. The electrolyte solution comprises an electrolyte salt and a solvent.

[0106] In some examples, the electrolyte salt is one or more of the following: lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalatoborate (LiDFOB), lithium bisoxalatoborate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluorobis(oxalato)phosphate (LiDFOP), and lithium tetrafluorooxalate phosphate (LiTFOP).

[0107] In some examples, the solvent is one or more of the following: ethylene carbonate (EC), propylene carbonate (PC), ethylmethyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), butylene carbonate (BC), fluoroethylene carbonate (FEC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butanoate (MB), ethyl butanoate (EB), γ-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), ethyl methyl sulfone (EMS), and diethyl sulfone (ESE).

[0108] In some embodiments, the electrolyte may optionally further contain additives. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, or additives that can improve some aspects of the battery's performance, such as additives that improve the battery's overcharge performance, additives that improve the battery's high-temperature performance, and additives that improve the battery's low-temperature performance. [Separator] The separator is positioned between the positive electrode plate and the negative electrode plate, separating the two plates. The lithium-ion battery according to this disclosure is not particularly limited in terms of the type of separator, and any well-known porous separator used in lithium-ion batteries can be used. For example, the separator may be one or more of the following: a glass fiber thin film, a nonwoven fabric thin film, a polyethylene thin film, a polypropylene thin film, a polyvinylidene fluoride thin film, and a multilayer composite thin film containing one or more of these.

[0109] A lithium-ion battery can be obtained by manufacturing a positive electrode plate, a negative electrode plate, and a separator as an electrode assembly using a lamination or winding process, placing the separator between the positive and negative electrode plates to separate them, placing the electrode assembly in a package, injecting an electrolyte, and sealing it.

[0110] The lithium-ion battery package is used to enclose the electrode assembly and electrolyte. In some embodiments, the lithium-ion battery package may be a rigid case, such as a rigid plastic case, an aluminum case, or a steel case, or a soft pack, such as a bag-shaped soft pack. The material of the soft pack may be a plastic containing one or more types, such as polypropylene (PP), polybutylene terephthalate (PBT), and polybutylene succinate (PBS).

[0111] In this disclosure, the shape of the lithium-ion battery is not particularly limited and may be cylindrical, rectangular, or any other shape.

[0112] In some embodiments, lithium-ion batteries can be assembled as a battery module, and the number of lithium-ion batteries included in the battery module may be multiple, with the specific number being adjusted according to the application and capacity of the battery module.

[0113] In some embodiments, the above-mentioned battery modules can be assembled as a battery pack, and the number of battery modules included in the battery pack can be adjusted according to the application and capacity of the battery pack.

[0114] This disclosure provides an electrical device, which includes a lithium-ion battery according to the above-described embodiment.

[0115] This disclosure further provides an electrical device, which includes at least one of a lithium-ion battery, battery module, or battery pack as relating to this disclosure. The lithium-ion secondary battery, battery module, or battery pack may be used as a power source for the device or as an energy storage unit for the device. Examples of such devices include, but are not limited to, portable devices (e.g., mobile phones, laptops, etc.), electric vehicles (e.g., fully electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), trains, ships and satellites, and energy storage systems. The device may select a lithium-ion battery, battery module, or battery pack depending on its usage requirements.

[0116] The features and performance of the present disclosure will be described in more detail below with reference to the examples provided.

[0117] Example 1 The method for preparing a lithium-ion battery includes the following steps.

[0118] (1) Nanoseed crystals were prepared using the coprecipitation method under supergravity conditions.

[0119] Nickel sulfate, cobalt(II) sulfate, and manganese(II) sulfate were weighed out so that the molar ratio of nickel, cobalt, and manganese was 80:10:10, and dissolved in deionized water to obtain a nickel-cobalt-manganese mixed salt solution with a total molar concentration of cations of 2 M (mol / L). This solution was then transferred to the first liquid storage tank of a rotating bed with a spiral channel, and mixed aqueous solutions were prepared so that the concentrations of sodium hydroxide and ammonia were 4 M and 2 M, respectively, and transferred to the second liquid storage tank. 100 mL of aqueous ammonia with a pH of 10.5 was added to the reactor as the reaction base solution. The rotation speed of the rotating bed was set to 1200 rpm. The solution from the first liquid storage tank was pumped into the rotating bed reactor at a rate of 80 mL / min, and the solution from the second liquid storage tank was also pumped into the rotating bed reactor. The pH was maintained at 11, and at the same time, a centrifugal pump was started to circulate the mixture in a supergravity apparatus. When D50 reached 350 nm, the supply of solution from the first and second liquid storage tanks was stopped, and the rotation of the rotating bed was stopped. The SEM of the obtained precipitate is shown in Figure 1A, and the particle size of the precipitate is relatively small. The precipitate was allowed to stand and age for 8 hours to obtain the first reaction solution containing seed crystals. The SEM of the seed crystals is shown in Figure 1B, and the precipitate particles aggregated to form seed crystals, and the particle size increased.

[0120] (2) A ternary cathode material precursor was prepared.

[0121] The first reaction mixture containing the above seed crystals was transferred to a reaction vessel, the reaction temperature was raised to 80°C, sulfuric acid was added to adjust the pH to 10, and a nickel-cobalt-manganese mixed salt solution and a 0.03 M aqueous solution of sodium ligninsulfonate as an aqueous solution of crystal structure modifier were added to the reaction vessel in parallel using a metering pump at a constant rate of 0.3 mL / min. A mixed solution of sodium hydroxide and ammonia was added to adjust the ammonia concentration to 0.5 mol / L, the pH was maintained at 10, and the mixture was stirred at a rotational speed of 500 rpm. When D50 reached 10 μm, the supply of materials was stopped and the mixture was aged for 12 hours to obtain a ternary cathode material precursor slurry. The ternary cathode material precursor slurry was subjected to pressure filtration, followed by washing with a hot alkaline solution and then pure water, and then drying, sieving, and demagnetization to obtain the Ni ternary cathode material precursor. 0.8 Co0.1 Mn 0.1 (OH)2 was obtained. Photographs of its appearance and cross-section are shown in Figures 1C and 1D, respectively. A ternary cathode material precursor was obtained with relatively good sphericity, a relatively dense interior, and a sparse outer layer. Here, the hot alkaline solution was prepared at a temperature of 60°C, with a concentration of 60 g / L, the alkali being sodium hydroxide, and the drying conditions were 130°C for 5 hours.

[0122] (3) A ternary cathode material was prepared.

[0123] A precursor material and lithium hydride were uniformly mixed in a high-speed mixer to obtain a mixed powder, with a molar ratio of Li / (Ni+Co+Mn) of 1.05:1. The mixed powder was placed in a tube furnace and calcined under an oxygen gas atmosphere. During the calcination process, the temperature was first raised to 500°C at a rate of 2°C / min and held for 5 hours, then raised to 780°C at a rate of 2°C / min and held for 12 hours, and finally allowed to cool naturally to obtain a black powdery ternary cathode material. Photographs of its appearance and cross-section are shown in Figures 1E and 1F, respectively. As shown in the figures, the ternary cathode material has a relatively dense structure and relatively few pores. The cross-section of the ternary cathode material after 100 cycles at 1C is shown in Figure 2A. As can be seen from the figure, fine cracks are present in only some of the particles, indicating relatively good stability.

[0124] (4) Electrode preparation: The ternary cathode material, conductive carbon black, and PVDF were weighed in a mass ratio of 8:1:1, thoroughly polished, placed in a container, an appropriate amount of NMP solvent was added, and stirred in a stirrer for 24 hours to form a uniform slurry. Using a wet film deposition apparatus, the prepared slurry was uniformly coated onto clean aluminum foil, with a coating amount of 2.5 ± 0.05 mg / cm². 2 Then, it was placed in a vacuum drying box at 100°C and dried for 24 hours. After that, the positive electrode plate was placed in a hydraulic machine and roll-rolled at a pressure of 6 MPa.

[0125] (5) Assembly of button cell: The prepared ternary positive electrode material was further punched out as a circular positive electrode plate with a diameter of 12 mm, a metallic lithium circular sheet was used as the negative electrode, Celgard 2300 was used as the separator, and a 1 M LiPF6 solution (the solvent was a mixed solvent of EMC, DC, and DMC in a volume ratio of 1:1:1) was used as the electrolyte to assemble a CR2032 type button cell.

[0126] Example 2 The method for preparing a lithium-ion battery includes the following steps.

[0127] (1) Nanoseed crystals were prepared using the coprecipitation method under supergravity conditions.

[0128] Nickel sulfate, cobalt(II) sulfate, and manganese(II) sulfate were weighed out so that the molar ratio of nickel, cobalt, and manganese was 80:10:10, and dissolved in deionized water to obtain a nickel-cobalt-manganese mixed salt solution with a total molar concentration of cations of 2 M. This solution was then transferred to a first liquid storage tank of a rotating bed with a spiral channel, and mixed aqueous solutions were prepared so that the concentrations of sodium hydroxide and ammonia were 4 M and 2 M, respectively, and transferred to a second liquid storage tank. 100 mL of aqueous ammonia with a pH of 10.5 was added to the reactor as a reaction base solution, the rotation speed of the rotating bed was set to 1000 rpm, the solution from the first liquid storage tank was pumped into the rotating bed reactor at a rate of 50 mL / min, and the solution from the second liquid storage tank was pumped into the rotating bed reactor, maintaining the pH at 11, and at the same time the centrifugal pump was started and the mixed solution was circulated in a supergravity apparatus. When D50 reached 220 nm, the supply of solution from the first and second liquid storage tanks was stopped, the rotation of the rotating bed was stopped, and the mixture was allowed to stand and age for 12 hours to obtain the first reaction solution containing seed crystals.

[0129] Steps (2) to (5) were the same as in Example 1.

[0130] Example 3 The method for preparing a lithium-ion battery includes the following steps.

[0131] (1) Nanoseed crystals were prepared using the coprecipitation method under supergravity conditions.

[0132] Nickel sulfate, cobalt(II) sulfate, and manganese(II) sulfate were weighed out so that the molar ratio of nickel, cobalt, and manganese was 80:10:10, and dissolved in deionized water to obtain a nickel-cobalt-manganese mixed salt solution with a total molar concentration of cations of 2 M. This solution was then transferred to a first liquid storage tank of a rotating bed with a spiral channel, and mixed aqueous solutions were prepared so that the concentrations of sodium hydroxide and ammonia were 4 M and 2 M, respectively, and transferred to a second liquid storage tank. 100 mL of aqueous ammonia with a pH of 10.5 was added to the reactor as a reaction base solution, the rotation speed of the rotating bed was set to 1500 rpm, the solution from the first liquid storage tank was pumped into the rotating bed reactor at a rate of 100 mL / min, and the solution from the second liquid storage tank was pumped into the rotating bed reactor, maintaining the pH at 11, and at the same time the centrifugal pump was started and the mixed solution was circulated in a supergravity apparatus. When D50 reached 450 nm, the supply of solution from the first and second liquid storage tanks was stopped, the rotation of the rotating bed was stopped, and the mixture was allowed to stand and age for 6 hours to obtain the first reaction solution containing seed crystals.

[0133] Steps (2) to (5) were the same as in Example 1.

[0134] Example 4 The method for preparing the lithium-ion battery differs from that of Example 1 in the following respects: In step (2), a 0.03 M sodium polypropylene solution was used as the aqueous solution of the crystal structure modifier instead of a 0.03 M sodium ligninsulfonate solution.

[0135] Example 5 The method for preparing the lithium-ion battery differs from Example 1 in the following respects: In step (2), a 0.05 M sodium ligninsulfonate solution was used as the aqueous solution of the crystal structure modifier instead of a 0.03 M sodium ligninsulfonate solution.

[0136] Example 6 The method for preparing the lithium-ion battery differs from that of Example 1 in the following respects: In step (2), a 0.01 M sodium ligninsulfonate solution was used as the aqueous solution of the crystal structure modifier instead of a 0.03 M sodium ligninsulfonate solution.

[0137] Example 7 The method for preparing the lithium-ion battery differs from Example 1 in the following respects: In step (1), the molar ratio of nickel, cobalt, and manganese is 50:30:20; in step (2), instead of 0.03 M sodium ligninsulfonate as the aqueous solution of the crystal structure modifier, a 0.01 M sodium polypropylene solution is used, the flow rate is changed from 0.3 mL / min to 0.2 mL / min, and the ammonia concentration is 0.8 M; and the ternary cathode material precursor is Ni 0.5 Co 0.3 Mn 0.2 (OH)2 was obtained.

[0138] Comparative Example 1 The method for preparing a lithium-ion battery includes the following steps.

[0139] (1) Crystal nuclei were prepared without using the supergravity coprecipitation method.

[0140] 100 mL of pH 10.5 aqueous ammonia was added to the reaction vessel as the reaction base solution. A 2 M nickel-cobalt-manganese mixed salt solution and a 0.4 M aqueous ammonia solution were added to the reaction vessel in parallel at a constant rate using metering pumps. The flow rate of the nickel-cobalt-manganese mixed salt solution was set to 80 mL / min, and at the same time, sodium hydroxide solution was added to bring the pH of the reaction solution to 11, and the ammonia concentration in the reaction solution to 0.4 mol / L. The stirring speed was set to 300 rpm, and the temperature of the reaction vessel was set to 50°C. Before supplying the materials, the reaction vessel was replaced with an inert gas atmosphere, and the reaction process was monitored in real time. When the D50 of the material reached 1 μm, the supply of the solution to the reaction vessel was stopped, and after the reaction was completed, the mixture was aged for 15 hours to obtain seed crystals.

[0141] Steps (2) to (5) were the same as in Example 1. A cross-sectional photograph of the obtained ternary cathode material precursor is shown in Figure 3. The ternary cathode material precursor had a relatively large number of pores both inside and in the outer layer, a low effective pore volume ratio, and a relatively high impurity content.

[0142] Comparative Example 2 The method for preparing the lithium-ion battery differs from Example 1 in the following respects: Sodium dodecylbenzenesulfonate was used as the crystal structure modifier instead of sodium ligninsulfonate.

[0143] Comparative Example 3 As a method for preparing lithium-ion batteries, metal sulfates were weighed in a molar ratio of Ni:Co:Mn = 0.8:0.1:0.1 and prepared as a mixed salt solution with a total concentration of 2 M using deionized water. Then, NaOH and aqueous ammonia were prepared as a mixed alkaline solution with a molar ratio of 3:1 using deionized water, resulting in a NaOH concentration of 0.2 M. Sodium dodecylbenzenesulfonate was added to the mixed alkaline solution so that the mass ratio of NaOH to surfactant was 9:1. 100 mL of aqueous ammonia with a pH of 11 was added to the reaction vessel as the reaction base solution. The stirring speed was set to 600 rpm and the reaction temperature to 50°C. The mixed salt solution and mixed alkali solution were slowly added to the reaction vessel at a constant rate, the flow rate of the nickel-cobalt-manganese mixed salt solution was set to 80 mL / min, and the pH was stably maintained at 11. Before supplying the materials, the reaction vessel was replaced with an inert gas atmosphere, and the reaction process was monitored in real time. When D50 reached 6 μm, the material supply was stopped and the mixture was aged for 15 hours. The ternary cathode material precursor slurry was then pressure filtered, followed by washing with hot alkaline solution and pure water in sequence, and finally drying, sieving, and demagnetizing to obtain the Ni ternary cathode material precursor. 0.8 Co 0.1 Mn 0.1 (OH)2 was obtained.

[0144] Steps (3) to (5) were the same as in Example 1.

[0145] Comparative Example 4 The method for preparing a lithium-ion battery includes the following steps.

[0146] (1) Nanoseed crystals were prepared using the coprecipitation method under supergravity conditions.

[0147] Nickel sulfate, cobalt(II) sulfate, and manganese(II) sulfate were weighed and dissolved in deionized water to obtain a nickel-cobalt-manganese mixed salt solution with a total molar concentration of cations of 2 M. This solution was then transferred to a first liquid storage tank in a rotating bed with a spiral channel. Mixed aqueous solutions were then prepared so that the concentrations of sodium hydroxide and ammonia were 4 M and 2 M, respectively, and transferred to a second liquid storage tank. 100 mL of aqueous ammonia with a pH of 10.5 was added to the reactor as a reaction base solution, the rotation speed of the rotating bed was set to 1800 rpm, the solution from the first liquid storage tank was pumped into the rotating bed reactor at a rate of 120 mL / min, and the solution from the second liquid storage tank was pumped into the rotating bed reactor, maintaining the pH at 10.5, and at the same time the centrifugal pump was started and the mixed solution was circulated in a supergravity apparatus. When D50 reached 180 nm, the supply of solution from the first and second liquid storage tanks was stopped, the rotation of the rotating bed was stopped, and the mixture was allowed to stand for 12 hours of aging to obtain the first reaction solution containing seed crystals.

[0148] The molar ratio of nickel, cobalt, and manganese was 80:10:10.

[0149] (2) A ternary cathode material precursor was prepared.

[0150] The first reaction mixture containing the above seed crystals was transferred to a reaction vessel, the reaction temperature was raised to 80°C, sulfuric acid was added to adjust the pH to 10, and a nickel-cobalt-manganese mixed salt solution and an aqueous solution of a crystal structure modifier (0.06 M sodium ligninsulfonate aqueous solution) were added to the reaction vessel in parallel with the reaction vessel at a constant rate of 0.3 mL / min using a metering pump. A mixed solution of sodium hydroxide and ammonia was added to adjust the ammonia concentration to 0.5 mol / L, the pH was maintained at 10, and the rotation speed was set to 500 rpm. When D50 reached 10 μm, the supply of materials was stopped and the mixture was aged for 12 hours to obtain a ternary cathode material precursor slurry. The ternary cathode material precursor slurry was subjected to pressure filtration, followed by washing with a hot alkaline solution and then pure water, and then drying, sieving, and demagnetization to obtain the Ni ternary cathode material precursor. 0.8 Co 0.1 Mn 0.1 (OH)2 was obtained. Here, the hot alkaline solution was prepared at a temperature of 60°C, with a concentration of 60 g / L, the alkali being sodium hydroxide, and the drying conditions were 130°C for 5 hours.

[0151] Steps (3) to (5) were the same as in Example 1. The cross-section of the obtained ternary cathode material after 100 cycles at 1C is shown in Figure 2B. There was a clear increase in cracking of the cathode material particles, and some of the cathode material particles were crushed, resulting in a clear decrease in cycle stability compared to Example 1.

[0152] Comparative Example 5 The method for preparing a lithium-ion battery includes the following steps.

[0153] (1) Nanoseed crystals were prepared using the coprecipitation method under supergravity conditions.

[0154] Nickel sulfate, cobalt(II) sulfate, and manganese(II) sulfate were weighed out so that the molar ratio of nickel, cobalt, and manganese was 80:10:10, and dissolved in deionized water to obtain a nickel-cobalt-manganese mixed salt solution with a total molar concentration of cations of 2 M. This solution was then transferred to a first liquid storage tank of a rotating bed with a spiral channel, and mixed aqueous solutions were prepared so that the concentrations of sodium hydroxide and ammonia were 4 M and 2 M, respectively, and transferred to a second liquid storage tank. 100 mL of aqueous ammonia with a pH of 10.5 was added to the reactor as a reaction base solution, the rotation speed of the rotating bed was set to 1000 rpm, the solution from the first liquid storage tank was pumped into the rotating bed reactor at a rate of 120 mL / min, and the solution from the second liquid storage tank was pumped into the rotating bed reactor, maintaining the pH at 10.5, and at the same time the centrifugal pump was started and the mixed solution was circulated in a supergravity apparatus. When D50 reached 418 nm, the supply of solution from the first and second liquid storage tanks was stopped, the rotation of the rotating bed was stopped, and the mixture was allowed to stand and age for 12 hours to obtain the first reaction solution containing seed crystals.

[0155] (2) A ternary cathode material precursor was prepared.

[0156] The first reaction mixture containing the seed crystals described above was transferred to a reaction vessel, the reaction temperature was raised to 80°C, sulfuric acid was added to adjust the pH to 10, and the nickel-cobalt-manganese mixed salt solution was added to the reaction vessel at a constant rate using a metering pump. A mixed solution of sodium hydroxide and ammonia was added to adjust the ammonia concentration to 0.8 mol / L, the pH was maintained at 10, and the rotation speed was set to 500 rpm. When D50 reached 10 μm, the supply of materials was stopped and the mixture was aged for 12 hours to obtain a ternary cathode material precursor slurry. The ternary cathode material precursor slurry was subjected to pressure filtration, followed by washing with a hot alkaline solution and then pure water, and then drying, sieving, and demagnetization to obtain the Ni ternary cathode material precursor. 0.8 Co 0.1 Mn 0.1 (OH)2 was obtained. Here, the hot alkaline solution was prepared at a temperature of 60°C, with a concentration of 60 g / L, the alkali being sodium hydroxide, and the drying conditions were 130°C for 5 hours.

[0157] Steps (3) to (5) were the same as in Example 1. The obtained ternary cathode material precursor had relatively low sphericity, and its SEM image is shown in Figure 4.

[0158] The performance of the ternary cathode material precursors obtained in the above examples and comparative examples was measured, and the measurement results are shown in Table 1. The performance of some of the ternary cathode materials obtained in the above examples and comparative examples was also measured, and the measurement results are shown in Table 2. The specific measurement method was as follows.

[0159] (1) The overall and cross-sectional microstructure of the sample to be measured was observed using a JEOLJSM-6490LV scanning electron microscope.

[0160] (2) The effective specific pore volume fraction was measured using the following method.

[0161] V 総 Measurement: The liquid level of mercury in a container containing mercury is measured and recorded as H0. The sample to be measured is placed in the container containing mercury. Since the density of the sample to be measured is less than the density of mercury, the material floats on the liquid surface. The sample floating on the liquid surface is pushed down to below the liquid surface at a speed of less than 50 mm / min using a piston with a volume of V'. After the liquid surface has stabilized, the liquid level height is measured and recorded as H1. Based on H0, H1 and other shape parameters of the container, the volumes V0 and V1, which correspond to the liquid level heights H0 and H1 respectively, can be calculated. Therefore, V 総 V according to =V1-V0-V' 総 I calculated it.

[0162] Measurement method: Read the volume V0 of pure water, place the sample to be measured in a graduated cylinder containing deionized water at 25°C, and after the sample has sunk to the bottom, perform ultrasound for 5 minutes, then read the volume V1, which was found to be = V1 - V0.

[0163] V 材 Measurement method: The density of the sample to be measured is measured using the water displacement method, and the density range of nickel-cobalt-manganese hydroxide is 3.4~3.8 g / cm³. 3This was measured to determine the V of the ternary cathode material precursor. 材 The range is 0.263~0.294cm 3 The density was / g. The density range of single-crystal lithium nickel-cobalt-manganate was 2.5~2.8 g / cm³. 3 Therefore, the ternary cathode material V 材 The range is 0.357~0.400cm 3 It was / g.

[0164] Effective specific pore volume ratio = (V 総 -V 排 ) / (V 総 -V 材 The effective specific pore volume ratio was calculated according to the formula ) × 100%.

[0165] (3) Particle size: Measurement was performed using an MS3000 type laser diffraction particle size analyzer.

[0166] (4) BET specific surface area The specific surface area of ​​the sample was obtained by analyzing data in the medium-to-low pressure range of the nitrogen adsorption / desorption curve using the BET formula. The measurement was performed using the AutosorbIQ2 fully automated specific surface area and pore size analyzer manufactured by Anton Paar GmbH in Austria.

[0167] (5) Analysis of chemical composition: Measurements were performed using a PEAvio200 inductively coupled plasma emission spectrometer (ICP-OES).

[0168] (6) Tap density: GB / T 21354-2008 The tap density of powder products was measured according to the general measurement method for tap density.

[0169] (7) Electrochemical performance: Rate performance was measured using the LANHECT2001A battery evaluation system. The measurement conditions were a temperature of 25°C, a voltage range of 3 to 4.5V, and 1C = 180mA / g.

[0170] [Table 1]

[0171] By adjusting the methods and reaction parameters in preparation steps (1) and (2), the effective specific pore volume fraction of the spherical ternary cathode material precursor can be controlled, further affecting the tap density and electrochemical properties of the material. Specifically, the denser the structure of the seed crystal obtained in step (1), the smaller the particle size and the higher the effective specific pore volume fraction of the resulting precursor. In step (2), the polyanionic surfactant has a superior crystal structure modifying effect compared to low molecular weight surfactants, resulting in a higher effective specific pore volume fraction of the resulting precursor, because the steric hindrance effect of sodium ligninsulfonate is more pronounced. As can be seen by comparing Examples 1, 5, and 6, under the same conditions, the higher the concentration of the crystal structure modifier, the higher the effective specific pore volume fraction of the precursor and the less residual impurity elements there are inside the material.

[0172] [Table 2]

[0173] Comparing Example 1 with Comparative Example 2, Comparative Example 2 had a higher specific surface area but lower rate performance. Generally, a larger specific surface area increases the contact area between lithium ions and the electrolyte, leading to higher lithium ion transport efficiency. This is because, although Comparative Example 2 had a higher specific surface area, it used a low-molecular-weight material as a crystal shape modifier, resulting in insufficient steric hindrance compared to a high-molecular-weight crystal shape modifier. Furthermore, the prepared ternary cathode material had a relatively large number of micropores on its surface. Since micropores have lower wettability to the electrolyte than mesopores or macropores, the effective contact area with the electrolyte was relatively small, resulting in lower rate performance than Example 1.

[0174] Comparing the ternary cathode materials obtained in Example 1 and Example 4, both had similar tap densities, but Example 1 had a superior effective pore volume ratio and therefore higher rate performance. First, similar tap densities indicate similar internal density of the ternary cathode materials. The difference lies in the fact that the volume of pores into which the electrolyte can penetrate does not match among the external pores of the ternary cathode materials, and the smaller the pore diameter, the lower the wettability of the pore due to the tension of the liquid. In other words, the ternary cathode material from Example 4 had a relatively large number of micropores, while the ternary cathode material from Example 1 had a relatively large number of mesopores or macropores, resulting in higher lithium ion transport efficiency and superior rate performance.

[0175] Industrial applicability The ternary cathode material precursor according to this disclosure has an effective specific pore volume ratio of 75% to 90%, which can contribute to reducing the amount of residual impurities in the precursor. When a cathode material is prepared using this precursor, lithium can penetrate into the interior of the material, and a cathode material with a perfect crystal structure and uniform elemental distribution can be formed. The cathode material prepared using this precursor has relatively excellent cycle stability and rate performance.

Claims

1. A ternary cathode material precursor, The general formula for the ternary cathode material precursor is Ni ａ Co ｂ M １－ａ－ｂ (OH) ２ The following conditions must be met: 0.3 ≤ a < 0.98, 0 < b < 0.5, and 0 < 1-a-b < 0.5; M is at least one of Mn and Al; the ternary cathode material precursor includes effective pores and ineffective pores, the effective pores refer to pores into which water can enter under standard atmospheric pressure, and the ineffective pores refer to pores into which water cannot enter under standard atmospheric pressure; and the effective specific pore volume ratio of the ternary cathode material precursor is 75% to 90%. Here, the effective specific pore volume ratio = V 有効 / V 孔 ×100%, where V 有効 refers to the specific pore volume of effective pores, with the unit of cm ３ / g, and V 無効 refers to the specific pore volume of ineffective pores, with the unit of cm ３ / g, and V 孔 = V 有効 +V 無効 is as follows A ternary cathode material precursor characterized by the following features.

2. The ternary cathode material precursor is (1) V 孔 0.01 cm ３ / g ~ 0.06cm ３ The fact that it is / g, (2) V 有効 = V 総 -V 排 V 孔 = V 総 -V 材 And here, V 総 = V 材 +V 有効 +V 無効 This refers to the volume of mercury displaced by a ternary cathode material precursor per unit mass when immersed in mercury, and its unit is cm³. ３ / g, V 排 = V 材 +V 無効 This is the volume of water displaced by a ternary cathode material precursor per unit mass when immersed in water, and its unit is cm³. ３ / g, V 材 This is the reciprocal of the density of the ternary cathode material precursor, (3) The above V 有効 and V 孔 Each of the measurement processes is performed at temperatures between 4°C and 80°C, (4) The D50 of the ternary cathode material precursor is 8 μm to 12 μm, (5) The specific surface area of ​​the ternary cathode material precursor is 6.4 m². ２ / g to 7.5m ２ The fact that it is / g, (6) The tap density of the ternary cathode material precursor is 1.9 g / cm³. ３ ~2.3 g / cm ３ That is, It satisfies at least one of the characteristics (1) to (6) of the above. The ternary cathode material precursor according to feature 1.

3. The total weight percentage of sodium and sulfur elements in the ternary cathode material precursor is less than 0.21 wt%. and / or, the weight percentage of the element sodium in the ternary cathode material precursor is less than 0.03 wt%, and / or, the weight percentage of sulfur element in the ternary cathode material precursor is less than 0.21 wt%. A ternary cathode material precursor according to feature 1 or 2.

4. A method for preparing a ternary cathode material precursor according to any one of claims 1 to 3, A seed crystal preparation step involves preparing nanoseed crystals of a ternary cathode material precursor using a coprecipitation method under supergravity conditions, The step includes growing the nano seed crystals to obtain the ternary cathode material precursor. A method for preparing a ternary cathode material precursor, characterized by the following features.

5. The seed crystal preparation step includes the steps of: placing ammonia water with a pH of 10 to 11 as a reaction base liquid into a rotating bed reactor; adding nickel-cobalt M mixed salt solution and a mixed aqueous solution containing a precipitant and a complexing agent to the two liquid storage tanks of the rotating bed in parallel to the rotating bed reactor; maintaining the pH value at 10.5 to 11.5; stopping the supply of materials when the precipitate reaches a first predetermined particle size; stopping the rotation of the rotating bed; allowing it to stand and age to obtain a first reaction solution containing seed crystals; The seed crystal preparation step is as follows: A. The first predetermined particle size D50 is 200 nm to 500 nm, B. In the aforementioned mixed aqueous solution, the concentration of the precipitating agent is 3 mol / L to 5 mol / L, and the concentration of the complexing agent is 1.5 mol / L to 2.5 mol / L. C. The rotational speed of the rotating floor shall be 1000 rpm to 1500 rpm, D. The salt in the nickel-cobalt M mixed salt solution is one of a nitrate, hydrochloride, or sulfate. E. The molar ratio of nickel-cobalt M is 35-98:1-35:1-35, F. The total concentration of the three elements nickel, cobalt, and M in the nickel-cobalt-M mixed salt solution is 1.5 mol / L to 2.5 mol / L. G. The flow rate of the nickel-cobalt M mixed salt solution is 50 mL / min to 100 mL / min, H. The precipitating agent is potassium hydroxide or sodium hydroxide, I. The complexing agent is one of ammonia water, ammonium nitrate, ammonium sulfate, and ammonium chloride. It further satisfies at least one of the characteristics A to I. The method for preparing a ternary cathode material precursor according to feature 4.

6. The seed crystal growth step includes adjusting the pH of the first reaction solution containing the seed crystal to 9.5 to 10.5, adding the nickel-cobalt M mixed salt solution, an aqueous solution of the crystal structure modifier, and a mixed aqueous solution containing a precipitant and a complexing agent to the first reaction solution containing the seed crystal, obtaining a second reaction solution, maintaining the pH of the second reaction solution at 9.5 to 10.5, adjusting the ammonia concentration to 0.4 mol / L to 0.8 mol / L, stopping the material supply when the precipitate reaches a second predetermined particle size, allowing it to stand and age, and then obtaining a slurry containing the ternary cathode material precursor. The seed crystal growth step is, a. The crystal structure modifier is an anionic surfactant, b. The concentration of the aqueous solution of the crystal structure modifier is 0.01 mol / L to 0.05 mol / L, c. The flow rate of the nickel-cobalt M mixed salt solution is 0.2 mL / min to 0.5 mL / min, d. The flow rate of the aqueous solution of the crystal structure modifier shall be 0.2 mL / min to 0.5 mL / min, e. The second predetermined particle size D50 is 8 μm to 12 μm, f. The process further includes the steps of performing solid-liquid separation on the slurry containing the ternary cathode material precursor, washing the solid phase using an alkaline solution and pure water in sequence, drying, sieving, and demagnetizing to obtain the ternary cathode material precursor, It further includes at least one of the features a to f. A method for preparing a ternary cathode material precursor according to feature 4 or 5.

7. The aforementioned crystal structure modifiers are sodium polypropyleneate and sodium lignin sulfonate. and / or, the alkaline solution is a sodium hydroxide solution or a potassium hydroxide solution with a concentration of 50 g / L to 70 g / L and a temperature of 50°C to 80°C. A method for preparing a ternary cathode material precursor according to feature 6.

8. A ternary cathode material obtained by mixing a ternary cathode material precursor according to any one of claims 1 to 3 or a ternary cathode material precursor prepared by the preparation method according to any one of claims 4 to 7 with a lithium source and firing, wherein the ternary cathode material is g. The effective specific pore volume ratio of the ternary cathode material is 75% to 90%, h. The specific surface area of ​​the ternary cathode material is 0.4 m². ２ / g to 0.7m ２ The fact that it is / g, i. The tap density of the ternary cathode material is 2.6 g / cm³. ３ ~2.9 g / cm ３ That is, It further satisfies at least one of the characteristics g to i. A ternary cathode material characterized by the following features.

9. The initial discharge ratio capacity at 0.1C corresponding to the ternary cathode material is 192 mAh / g to 208 mAh / g. And / or, the initial discharge ratio capacity at 1C corresponding to the ternary cathode material is 167 mAh / g to 190 mAh / g. And / or, the capacity retention rate after 100 cycles at 1C corresponding to the ternary cathode material is 85% to 97%. And / or, the initial discharge ratio capacity at 5C corresponding to the ternary cathode material is 142 mAh / g to 165 mAh / g. The ternary cathode material according to feature 8.

10. A method for preparing a ternary cathode material according to claim 8 or 9, The ternary cathode material is obtained by mixing a ternary cathode material precursor prepared by any one of claims 1 to 3 or by the preparation method described in any one of claims 4 to 7 with a lithium source and firing. A method for preparing a ternary cathode material, characterized by the features described herein.

11. The firing temperature is 400°C to 800°C, and the firing time is 15 to 20 hours. A method for preparing a ternary cathode material according to feature 10.

12. The firing process includes single-stage firing and double-stage firing. In single-stage firing, the temperature is 400°C to 600°C and the duration is 4 to 6 hours. In double-stage firing, the temperature is 750°C to 800°C and the duration is 10 to 14 hours. A method for preparing a ternary cathode material according to feature 10 or 11.

13. During the firing process, the heating rate is 1.5°C / min to 2.5°C / min. A method for preparing a ternary cathode material according to any one of claims 10 to 12.

14. Includes the ternary cathode material described in claim 8 or 9 A positive electrode plate characterized by the following features.

15. Includes the positive electrode plate described in claim 14 A battery cell characterized by the following features.

16. Includes the positive electrode plate described in claim 14 A lithium-ion battery characterized by the following features.

17. Includes the lithium-ion battery described in claim 16 An electrical device characterized by the following features.

Images