A boron-coated fluorine-zirconium co-doped ternary positive electrode material, a preparation method and application thereof

Abstract

This invention belongs to the field of lithium-ion battery technology, specifically relating to a boron-coated fluorine-zirconium co-doped ternary cathode material, and further disclosing its preparation method and application. The boron-coated fluorine-zirconium co-doped ternary cathode material of this invention, based on traditional nickel-cobalt-manganese materials, employs a multi-element co-doping and coating composite modification method. ZrF4 and θ-Al2O3 are used as dopants, and B4C and γ-Al2O3 are used as coating agents for coating modification. Furthermore, a more structurally stable α-Al2O3 is used to form a secondary coating. The lithium-ion battery prepared from the ternary cathode material provided by this invention exhibits high specific capacity, rate capability, cycle performance, and application effectiveness, possessing advantages such as high specific capacity, low DCIR growth, and excellent overall performance over long cycle life.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery technology, specifically relating to a boron-coated fluorine and zirconium co-doped ternary cathode material, and further discloses its preparation method and application. Background Technology

[0002] With the rapid development of new energy vehicles recently, the demand for lithium-ion batteries has also increased dramatically. However, charging time and range anxiety are hindering its further development.

[0003] Currently, NCA and NCM type materials are highly promising candidates for high-energy-density lithium-ion battery cathode systems due to their high lithium storage capacity. However, cycling at high current densities significantly reduces the capacity of ternary cathode materials, severely hindering their large-scale application. This is mainly because the cathode material reacts with CO2 and H2O in the environment to generate LiOH and Li2CO3 on its surface. LiOH reacts with LiPF6 in the electrolyte to generate HF, which corrodes Ni and Mn, causing the surface coating to detach, resulting in reduced cycle / storage life. Furthermore, under high-voltage polarization during charging or high-temperature storage, Li2CO3 decomposes to produce CO2 and CH4, and the gradually increasing nickel content leads to severe Li / Ni mixing, resulting in unsatisfactory cycle and storage life. Therefore, to address the market demand for batteries that meet the requirements of fast charging, high power, high energy density, low cost, and high cost-effectiveness, ternary cathode materials with high energy density, long cycle life, and high power performance have been pushed to the forefront of research, and market demand continues to rise.

[0004] Reports indicate that doping with anionic and cation elements affects initial coulombic efficiency and cycle stability. Doping can, to some extent, suppress reversible phase transitions during charge and discharge. Doping can buffer changes in the layered structure during lithium insertion / extraction, reducing reactions between battery components in the charging state, thereby improving cycle life and safety performance. While fluorine doping reduces initial discharge capacity, it significantly improves rate performance and cycle performance, and its electrochemical performance at high temperatures is superior to undoped materials. AC impedance spectroscopy analysis shows that the addition of fluorine reduces charge transfer resistance and improves conductivity. Therefore, fluorine doping is highly beneficial for improving the electrochemical performance of materials. Further improvements can be made through surface conductivity modification, dual-gradient coating, calcination process improvements, the use of surface protective materials, and the application of special conductive materials.

[0005] For example, Chinese patent CN115028211A discloses a fluorine-doped nickel-cobalt-manganese-lithium ternary material that uses fluorine doping. A fluorine-containing compound is used as the fluorine source, reacting with nickel-cobalt-manganese-lithium oxides under specific conditions to synthesize the fluorine-doped nickel-cobalt-manganese-lithium ternary material via a solid-state method. This is achieved through fluorine doping... Replace O2 The doping of fluorine alters the valence state of transition metal ions, thereby changing their crystal structure parameters. More importantly, fluorine doping promotes grain growth and improves crystallinity. Furthermore, the doping level enhances the stability of the interface between the active material and the electrolyte, significantly improving cycle performance. However, this scheme uses only fluorine (F) anion doping, which cannot completely improve the material's long-cycle and rate performance. Excessive anion doping can lead to a decrease in electrical performance. In particular, the primary doping method uses NH4F, which has a melting point of 98°C, leaving residual nitrogen elements that negatively impact electrical performance. The amount of NH4F incorporated into the material after the high-temperature solid-state reaction is difficult to control, and there is a risk of excessively large intergranular gaps. Conversely, excessive impurity levels can cause uneven substitution, severely affecting electrical performance.

[0006] For example, Chinese patent CN108598398A discloses a composite cathode material co-coated with boron carbide and carbon. The coating layer of this material has high conductivity and corrosion resistance, thereby suppressing side reactions between the material and the electrolyte, stabilizing the material structure, and improving its cycle performance. However, this mainly concerns modified lithium iron phosphate cathode materials and does not cover other areas of cathode materials; the conductivity of both is similar, which presents certain limitations.

[0007] Furthermore, Chinese patent CN105098158A discloses a zirconium-doped lithium-ion battery lithium-rich cathode material, the chemical formula of which is Li. 1.2 (Mn 0.54 Ni 0.13 Co 0.13 ) 1-x Zr x O2 (0 < x < 1) helps reduce particle agglomeration, and the chemical reactions occurring in the hydrothermal system have a faster reaction rate. He Libo et al., in "Zirconium-doped Nickel-Cobalt-Manganese Ternary Materials and Their Preparation Methods," provided a Zr-doped ternary precursor scheme and subsequent preparation method. Zhang Bao et al., in "A Zirconium- and Multi-Anion-Doped Ternary Cathode Material Precursor and Its Preparation Method, Ternary Cathode Material," provided a Zr and multi-anion co-doped ternary precursor scheme and subsequent preparation method. Both methods utilize the mixing and addition of anions and cations at the precursor solution end to modify the material. However, they still face challenges such as elemental interface fusion and grain boundary diffusion growth defects during subsequent high-temperature preparation, requiring further modification during high-temperature calcination. Summary of the Invention

[0008] To this end, the technical problem to be solved by the present invention is to provide a boron-coated fluorine-zirconium co-doped ternary cathode material. The cathode material effectively improves the structure of the medium-high nickel ternary cathode material through the scheme of co-doping and coating of anions and cations, and has the advantages of stable structure, low DCIR value, and good rate performance, cycle performance, and storage performance.

[0009] The second technical problem to be solved by the present invention is to provide a preparation method and application of the above boron-coated fluorine-zirconium co-doped ternary cathode material.

[0010] To solve the above technical problems, a boron-coated fluorine-zirconium co-doped ternary cathode material according to the present invention is characterized in that it has a general formula as shown in LiNi x Co y Mn z Zr a Al b B c F d O 2-d and x + y + z + a + b + c + d = 1.

[0011] In the boron-coated fluorine-zirconium co-doped ternary cathode material of the present invention, the total molar amount of each metal element is 1, and the specific molar content of each element can be conventionally selected according to the required material ratio.

[0012] Preferably, in the boron-coated fluorine-zirconium co-doped ternary cathode material, the molar ratio of Ni x is 0.5 ≤ x < 1.0, the molar ratio of Co y is 0 < y ≤ 0.30, the molar ratio of Mn z is 0 < z ≤ 0.30, and x + y + z = 1; the molar ratio of Li: (x + y + z) is preferably 0.98 - 1.16:1.0, more preferably 0.99 - 1.12:1.0.

[0013] The present invention also discloses a method for preparing the boron-coated fluorine-zirconium co-doped ternary cathode material, including the following steps:

[0014] (1) According to the selected content ratio, take the ternary cathode material precursor Ni x Co y Mn z (OH)2, the lithium source material, and the fluorine-zirconium dopant are mixed and subjected to the first sintering treatment to obtain a ternary cathode material doped matrix.

[0015] (2) According to the selected content ratio, the ternary cathode material doped matrix is mixed with the boron coating agent and subjected to the second sintering treatment to obtain a ternary cathode material coated matrix.

[0016] (3) According to the selected content ratio, the ternary cathode material coating matrix is ​​mixed with aluminum-containing additives and subjected to a third sintering treatment to obtain the desired boron-coated fluorine-zirconium co-doped ternary cathode material.

[0017] Specifically, in the preparation method of the boron-coated fluorine-zirconium co-doped ternary cathode material, in step (1):

[0018] The ternary cathode material precursor Ni x Co y Mn z (OH)2, the lithium source material (in Li) + The molar ratio of the fluorinated zirconium dopant (based on the total amount of dopant elements) is 1:(0.96-1.30):(0.02-1.0).

[0019] As a preferred embodiment, the ternary cathode material precursor Ni x Co y Mn z (OH)2, the lithium source material (in Li) + The molar ratio of the fluorinated zirconium dopant (based on the total amount of dopant elements) is 1:(0.98-1.16):(0.05-0.6), more preferably 1:(0.99-1.12):(0.05-0.6).

[0020] The fluorinated zirconium dopant comprises a mixture of ZrF4 and θ-Al2O3;

[0021] Preferably, the ternary cathode material precursor Ni x Co y Mn z The mass ratio of (OH)2 to ZrF4 is 100:(0.05-1.0), preferably 100:(0.1-0.8), and more preferably 100:(0.35-0.55).

[0022] Preferably, the ZrF4 has a purity of 99.9% and its D 50 The particle size is 0.3μm-150μm, preferably 1μm-50μm, and more preferably 3μm-30μm;

[0023] Preferably, the ternary cathode material precursor Ni x Co y Mn z The mass ratio of (OH)2 to θ-Al2O3 is 100:(0.05-0.6), preferably 100:(0.1-0.5), and more preferably 100:(0.2-0.4).

[0024] Preferably, the θ-Al₂O₃ has a purity of 99.9% and its D50 The particle size is 1μm-50μm, preferably 2μm-30μm, and more preferably 3μm-20μm;

[0025] Preferably, the lithium source material is a lithium-containing compound, comprising one or a mixture of several of LiOH, LiOH·H2O, Li2CO3, or LiNO3. In application, the coarse lithium source particles can be mechanically ground to 3-20 μm, or commercially available lithium sources of this specification can be selected, preferably 4-8 μm; the ternary lithium source is preferably LiOH·H2O or Li2CO3.

[0026] Preferably, the ternary cathode material precursor is selected such that the particle size D of the small-particle high-nickel ternary precursor is... 50 (2-6μm), preferably 3.0-5.0μm; its large-particle high-nickel ternary precursor has a particle size D 50 (9-16μm), preferably 10-14μm.

[0027] Preferably, the mixing step uses a ball mill, can mill, plow mixer, or high-speed mixer to mix the materials evenly, then the mixture is placed in a small dry pot or sagger, shaken evenly, cut into pieces, and then sintered once; the mixing equipment is preferably a ball mill, plow mixer, or high-speed mixer.

[0028] Specifically, in the preparation method of the boron-coated fluorine-zirconium co-doped ternary cathode material, the first sintering step in step (1) includes: a first heating to 400-500℃ and holding for 2-6 hours in an oxygen-containing atmosphere, a second heating to 580-740℃ and holding for 2-5 hours, and a third heating to 740-970℃ and holding for 6-24 hours;

[0029] As a preferred embodiment, in step (1), the first sintering step includes: a first heating to 420-480℃ and holding for 3-5 hours in an oxygen-containing atmosphere, a second heating to 680-740℃ and holding for 3-4 hours, and a third heating to 740-970℃ and holding for 8-20 hours.

[0030] As a preferred embodiment, in step (1), the first sintering step includes: a first heating to 460°C and holding for 4 hours in an oxygen-containing atmosphere, a second heating to 680-740°C and holding for 3-4 hours, and a third heating to 740-970°C and holding for 10-18 hours.

[0031] Preferably, when the first sintering step is carried out in a muffle furnace or tube furnace mode, the heating rate of the first heating step, the second heating step, and the third heating step are controlled to be independent of each other at 1-5℃ / min, preferably at 2-4℃ / min, and more preferably at 3℃ / min.

[0032] Preferably, when the first sintering step is carried out in an atmosphere roller kiln or rotary kiln mode, the heating rates of the first, second, and third heating steps are controlled independently to be 1-30℃ / h, preferably 5-20℃ / h, and more preferably 10℃ / h.

[0033] The atmosphere used in the first sintering process is oxygen with a concentration ≥95%. After the first sintering, the material undergoes coarse crushing, fine crushing, sieving, and demagnetization to obtain a ternary cathode material doped matrix for subsequent coating. Preferably, the large particle size D of the ternary cathode material doped matrix after crushing and sieving is... 50 The particle size is 9-16 μm, preferably 10-14 μm; the particle size of the small particle matrix D 50 The thickness is 2.5-6.0 μm, preferably 3.0-5.0 μm.

[0034] Specifically, in the preparation method of the boron-coated fluorine-zirconium co-doped ternary cathode material, in step (2):

[0035] The molar ratio of the ternary cathode material doped matrix to the boron-containing coating agent (based on the total amount of coating elements) is 1:(0.02-0.3).

[0036] The boron-containing coating agent comprises a mixture of B4C and γ-Al2O3;

[0037] Preferably, the mass ratio of the ternary cathode material doped matrix to the B4C is 100:(0.05-0.25), more preferably 100:(0.08-0.20), and even more preferably 100:(0.10-0.15).

[0038] Preferably, the coating agent B4C has a purity of 99.0%, and its D... 50 The particle size is 100nm-1.5μm, preferably 80nm-1μm, and more preferably 40nm-70nm;

[0039] Preferably, the mass ratio of the ternary cathode material doped matrix to the γ-Al2O3 is 100:(0.08-0.3), more preferably 100:(0.10-0.22), and even more preferably 100:(0.12-0.18).

[0040] Preferably, the coating agent γ-Al2O3 has a purity of 99.9% and its D 50The particle size is 1nm-100nm, preferably 10nm-80μm, and more preferably 20nm-60nm.

[0041] Specifically, in the preparation method of the boron-coated fluorine-zirconium co-doped ternary cathode material, step (2) includes a second sintering step, which involves heating to 350-720℃ for calcination and holding for 1-24 hours; preferably, the sintering temperature is controlled at 400-680℃ and the holding time is 3-14 hours; more preferably, the sintering temperature is controlled at 420-580℃ and the holding time is 6-11 hours.

[0042] Preferably, in the second sintering step, the heating rate is controlled to be 1-20℃ / h.

[0043] The preparation method of the boron-coated fluorine-zirconium co-doped ternary cathode material of the present invention includes the following steps: when the Ni content x in the ternary cathode material is 0.5 ≤ x < 0.8, the ternary cathode material doped substrate can be directly coated; when the molar content x of Ni element in the ternary cathode material doped substrate is ≥ 0.8 (i.e., it is a high-nickel cathode material), before adding the boron-containing coating agent, the method further includes the steps of dispersing, washing and drying the ternary cathode material doped substrate.

[0044] Specifically, in its water washing process, the ratio of material to water is controlled at 1:0.5-3.0, and the washing time is 10-120s; preferably, the ratio of material to water is 1:1.0-2.0, and the washing time is 20-60s; more preferably, the ratio of material to water is 1:1.5, and the washing time is 30s. During the water washing process, the material is gradually injected into a plate and frame filter press for pre-dehydration. After pre-dehydration, nitrogen gas is introduced for purging for 1-4 hours, preferably 2-3 hours, and the moisture content of the filter cake is controlled to be ≤7%. Subsequently, the filter cake is put into a vacuum oven or a double cone dryer for drying and dehydration. The drying temperature is 120-200℃, and the drying time is 1-12 hours; preferably 130-180℃, 3-10 hours; more preferably 150-160℃, 4-8 hours. A high-nickel ternary doped matrix is ​​obtained after water washing and drying.

[0045] Specifically, in the preparation method of the boron-coated fluorine-zirconium co-doped ternary cathode material, in step (3), the aluminum-containing additive includes α-Al2O3;

[0046] Preferably, the mass ratio of the ternary cathode material coating matrix to the α-Al2O3 is 100:(0.05-0.20), more preferably 100:(0.08-0.18), and even more preferably 100:(0.1-0.15).

[0047] Preferably, the additive α-Al2O3 has a purity of 99.9% and its D 50The particle size is 1nm-100nm, preferably 10nm-80μm, and more preferably 20nm-60nm.

[0048] Specifically, in the preparation method of the boron-coated fluorine-zirconium co-doped ternary cathode material, step (3) includes the third sintering step, which involves heating to 200-400℃ for calcination and holding for 1-10 hours; preferably, the sintering temperature is controlled at 240-385℃ and the holding time is 3-8 hours; more preferably, the sintering temperature is controlled at 300-380℃ and the holding time is 4-7 hours.

[0049] Preferably, in the third sintering step, the heating rate is controlled to be 1-20℃ / h;

[0050] Specifically, the equipment used for the coating operation can be a high-speed mixer or a mechanical fusion machine, with a high-speed mixer being preferred;

[0051] Preferably, step (3) further includes crushing, sieving, and demagnetizing the obtained boron-coated fluorine-zirconium co-doped ternary cathode material; and it can be further mixed evenly in a batch mixing tank and protected by introducing dry gas (dehydration and decarbonization) or inert gas.

[0052] Preferably, in step (3), the large particle matrix particle size D of the boron-coated fluorine-zirconium co-doped ternary cathode material is... 50 The particle size is 9-16 μm, preferably 10-14 μm; the particle size of the small particle matrix D 50 The micrometer size is 2.5-6.0 μm, preferably 3.0-5.0 μm, and more preferably 3.2-4.8 μm.

[0053] Preferably, the batch mixing equipment can be a ribbon batch mixer or a high-speed mixer.

[0054] The present invention also discloses the use of the boron-coated fluorine-zirconium co-doped ternary cathode material or the boron-coated fluorine-zirconium co-doped ternary cathode material prepared by the method for preparing secondary battery cathode sheets or secondary batteries.

[0055] Preferably, the secondary battery includes a lithium-ion battery.

[0056] The present invention also discloses a secondary battery cathode sheet or a secondary battery prepared from the boron-coated fluorine-zirconium co-doped ternary cathode material or the boron-coated fluorine-zirconium co-doped ternary cathode material prepared by the method.

[0057] The boron-coated fluorine-zirconium co-doped ternary cathode material of this invention uses ZrF4 and θ-Al2O3 as dopants, based on traditional nickel-cobalt-manganese materials. The co-doped ZrF4 can introduce a fluxing effect, and its low melting point reduces calcination temperature and energy consumption, promotes grain growth, and improves crystallinity. Furthermore, the low melting point and monoclinic crystal structure of ZrF4 enhance structural stability and promote inward diffusion of Zr / Al / Li, effectively lowering the calcination temperature and reducing energy consumption. The synergistic use of θ-Al2O3 not only ensures structural stability during low-temperature processing but also guarantees the structural evolution characteristic of homogeneous transformation to a stable α-phase at high temperatures, further improving the structural and thermal stability of the nickel-cobalt-manganese ternary material. The boron-coated fluorine-zirconium co-doped ternary cathode material of this invention, through co-doping of ZrF4 and θ-Al2O3 and subsequent high-temperature sintering solid-state reaction, forms anion-cation co-doped F / Zr / Al, effectively improving reversible capacity, enhancing the stability of the interface between the active material and the electrolyte, and significantly improving its cycle performance. Simultaneously, it effectively reduces the solubility of manganese in organic electrolytes, improves microcracks in the ternary material structure, thereby widening ion channels and interlayer distances, improving the material's discharge efficiency and rate capability, enhancing its high-temperature electrochemical performance, reducing Li / Ni mixing, and ensuring the application performance of battery products.

[0058] The boron-coated fluorine-zirconium co-doped ternary cathode material of this invention is further modified by coating with B4C and γ-Al2O3. The B4C coating improves the surface conductivity of the ternary cathode material, repairs the surface particle morphology, enhances the corrosion resistance of the particle surface, and reduces the increase in cell DCIR and cycle impedance. This effectively improves the material's resistance to electrolyte corrosion, rate capability, surface conductivity, and ion migration ability. Simultaneously, the composite coating of γ-Al2O3 and B4C enhances the particle surface's resistance to hydrofluoric acid corrosion, inhibits the formation and generation of microcracks, improves high-temperature oxidation resistance, reduces surface impedance, increases surface electronic conductivity, and improves the first discharge efficiency, thus ensuring the application performance of the battery product.

[0059] The boron-coated fluorine-zirconium co-doped ternary cathode material of this invention further employs a secondary coating by mixing a more structurally stable α-Al2O3 with a Ni / Co / Mn / F / Zr / Al / B oxide matrix, thereby forming a surface gradient coating structure. This further improves surface conductivity, reduces surface residual alkali, and thus suppresses the occurrence of interfacial side reactions. It effectively enhances the surface gradient coating protective layer, thereby increasing the Li ion migration induction ability and improving the material's cycle performance.

[0060] The boron-coated fluorine-zirconium co-doped ternary cathode material of this invention adopts a composite modification method of multi-element co-doping and coating, which effectively improves the Li / Ni mixing and particle surface band effect in the cathode material. The lithium-ion battery prepared by the ternary cathode material provided by this invention has high specific capacity, rate capability, cycle performance and application effect, and has the advantages of high specific capacity, low DCIR growth and long cycle performance. Attached Figure Description

[0061] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein...

[0062] Figure 1 Flowchart of the preparation process of the ternary cathode material described in this invention;

[0063] Figure 2 In the middle (a)-(d), the SEM morphology characteristics of the ternary cathode materials in Examples 1-4 are respectively.

[0064] Figure 3 In the middle (a)-(d), the cycling curves of the ternary cathode materials in Examples 1-4 and Comparative Examples 1-4 are respectively.

[0065] Figure 4 The full-cell cycling curves at 25°C for the ternary cathode materials in Example 3 and Comparative Example 3 are shown.

[0066] Figure 5 The full-cell cycling curves at 45°C are shown for the ternary cathode materials in Example 3 and Comparative Example 3. Detailed Implementation

[0067] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention.

[0068] Example 1

[0069] like Figure 1 The process shown in this embodiment, the preparation method of boron-coated fluorine-zirconium co-doped ternary cathode material, includes the following steps:

[0070] (1) Prepare the precursor Ni of the following general formula according to conventional methods. 0.83 Co 0.11 Mn 0.06 (OH)2 (particle size D) 50 (3.6±0.5μm), and LiOH·H2O (D) was taken respectively. 50 (6±2 μm) and dopant ZrF4 (D 50 (5±2μm) and θ-Al2O3 (D50 Raw material (5±2μm); weigh the following masses of raw material respectively: Ni 0.83 Co 0.11 Mn 0.06 (OH)22000g, LiOH·H2O945.02g, ZrF49.1744g, θ-Al2O36.8092g;

[0071] The above materials were transferred to a high-speed mixer and dispersed in three stages: 200 rpm / 2 min, 800 rpm / 20 min, and 100 rpm / 3 min to ensure uniform mixing of the three powders. The mixture was then placed in a crucible and transferred to an atmosphere muffle furnace. Under a slightly positive pressure oxygen atmosphere, the temperature was increased to 460°C at a heating rate of 3°C / min and sintered at that temperature for 4.0 h. The temperature was then increased to 710°C and sintered at that temperature for 4.0 h. Finally, the temperature was increased to 860°C and sintered for 12.0 h. The sintered product was collected, cooled, crushed, and sieved to obtain the ternary cathode material doped matrix.

[0072] (2) The obtained doped substrate was washed with water at a water-to-material ratio of 1:1.5 for 30 seconds, vacuum filtered, and then dried in a vacuum oven at 150℃ for 6 hours. 1600g of the sample was then mixed with the coating agent B4C (D 50 (50±20nm) (1.6375g) 、 γ-Al2O3 (D 50 The three powders (40±20nm) (2.4211g) were put into a high-speed mixer and mixed in three stages: 100rpm / 2min, 1200rpm / 30min, and 200rpm / 3min. After the three powders were mixed evenly, they were put into a crucible and sintered at 530℃ for 8.0h in an oxygen atmosphere. After cooling, they were crushed and then sieved to remove magnetism, thus obtaining the ternary cathode material coated matrix.

[0073] (3) Take 1500g of the obtained coating substrate and mix it with the additive α-Al2O3 (D 50 The three powders (40±20nm) (1.1858g) were put into a high-speed mixer and mixed evenly in three stages: 100rpm / 2min, 1000rpm / 30min, and 200rpm / 3min. The mixture was then placed into a crucible and sintered at 350℃ for 5.0h in an oxygen or oxygen-air (5:5) atmosphere. After cooling, the mixture was crushed and then sieved to remove magnetism. The resulting ternary cathode material was then put into a batch mixing tank and mixed for 2h. The discharged material was then sieved to remove magnetism and packaged to obtain the finished ternary cathode material. The relevant physicochemical data were then tested.

[0074] Example 2

[0075] like Figure 1 The process shown in this embodiment, the preparation method of boron-coated fluorine-zirconium co-doped ternary cathode material, includes the following steps:

[0076] (1) Prepare the precursor Ni according to conventional methods. 0.83 Co 0.11 Mn 0.06 (OH)2(D 50 (12±1μm), LiOH·H2O (D) 50 (6±2 μm) and dopant ZrF4 (D 50 (5±2μm) and θ-Al2O3 (D 50 (5±2μm) raw materials; weigh Ni 0.83 Co 0.11 Mn 0.06 (OH)2 (2000g), LiOH·H2O (945.02g), ZrF4 (9.1744g), θ-Al2O3 (6.8092g);

[0077] The above materials were transferred to a high-speed mixer and mixed evenly using a three-stage mixing process: 200 rpm / 2 min, 800 rpm / 20 min, and 100 rpm / 3 min. The mixture was then placed in a crucible and transferred to an atmosphere muffle furnace under a slightly positive pressure oxygen atmosphere. The temperature was increased to 460°C at a rate of 3°C / min and held for 4.0 h. The temperature was then increased to 710°C and sintered for another 4.0 h. Finally, the temperature was increased to 840°C and sintered for another 12.0 h. The sintered product was collected, cooled, crushed, and sieved to obtain the ternary cathode material doped matrix.

[0078] (2) The obtained doped substrate was washed with water at a water-to-material ratio of 1:1.5 for 30 seconds, vacuum filtered, and then dried in a vacuum oven at 150℃ for 6 hours; 1600g of the sample was mixed with coating agent B4C (D 50 (50±20nm) (1.6375g) 、 γ-Al2O3 (D 50 The three powders (40±20nm) (2.4211g) were put into a high-speed mixer and mixed evenly in three stages: 100rpm / 2min, 1200rpm / 30min, and 200rpm / 3min. The mixture was then placed into a crucible and sintered at 480℃ for 8.0h under an oxygen atmosphere. After cooling, the mixture was crushed and demagnetized by sieving to obtain the ternary cathode material coating matrix.

[0079] (3) Take 1500g of the obtained coated substrate and mix it with the additive α-Al2O3 (D 50The three powders (40±20nm) (1.1858g) were put into a high-speed mixer and mixed evenly in three stages: 100rpm / 2min, 1000rpm / 30min, and 200rpm / 3min. The mixture was then placed into a crucible and sintered at 350℃ for 5.0h in an oxygen-air (5:5) atmosphere. After cooling, the mixture was crushed and demagnetized by sieving. The resulting ternary cathode material was then put into a batch mixing tank and mixed for 2h. The discharged material was demagnetized by sieving and packaged to obtain the finished ternary cathode material. The relevant physicochemical data were then tested.

[0080] Example 3

[0081] like Figure 1 The process shown in this embodiment, the preparation method of boron-coated fluorine-zirconium co-doped ternary cathode material, includes the following steps:

[0082] (1) Prepare the precursor Ni according to conventional methods. 0.63 Co 0.09 Mn 0.28 (OH)2(D 50 (3.8±0.5μm), Li2CO3 (D 50 (6±2 μm) and dopant ZrF4 (D 50 (5±2μm) and θ-Al2O3 (D 50 (5±2μm) raw materials; weigh Ni 0.63 Co 0.09 Mn 0.28 (OH)2 (2000g), Li2CO3 (844.97g), ZrF4 (8.4405g), θ-Al2O3 (7.5658g); the materials were transferred to a high-speed mixer and mixed evenly using a three-stage mixing process: 200 rpm / 2 min, 800 rpm / 20 min, and 100 rpm / 3 min. The mixture was then placed in a crucible and transferred to a muffle furnace. Under a slightly positive pressure oxygen atmosphere, the temperature was increased to 460℃ at 3℃ / min and sintered for 4.0 h, then increased to 710℃ and sintered for 4.0 h, and then increased to 955℃ and sintered for 12.0 h. After cooling, the mixture was crushed and sieved to obtain the ternary cathode material doped matrix.

[0083] (2) 1600g of the obtained ternary cathode material doped matrix was mixed with coating agent B4C (D 50 (50±20nm) (1.8421g) 、 γ-Al2O3 (D 50The three powders (40±20nm) (2.1184g) were put into a high-speed mixer and mixed evenly in three stages: 100rpm / 2min, 1200rpm / 30min, and 200rpm / 3min. The mixture was then placed into a crucible and sintered at 530℃ for 8.0h in a dry air atmosphere. After cooling, the mixture was crushed and then sieved to remove magnetism, thus obtaining the ternary cathode material coating matrix.

[0084] (3) Take 1500g of the obtained coating substrate and mix it with the additive α-Al2O3 (D 50 The three powders (40±20nm) (2.1184g) were added to a high-speed mixer and mixed in three stages: 100rpm / 2min, 1000rpm / 30min, and 200rpm / 3min. After the three powders were mixed evenly, they were placed in a crucible and sintered at 350℃ for 6.0h in a dry air atmosphere. After cooling, the mixture was crushed and demagnetized by sieving to obtain the ternary cathode material coating matrix. The obtained ternary cathode material was added to a batch mixing tank and mixed for 2h. After discharge, the material was demagnetized by sieving and packaged to obtain the finished ternary cathode material, and the relevant physicochemical data were tested.

[0085] Example 4

[0086] like Figure 1 The process shown in this embodiment, the preparation method of boron-coated fluorine-zirconium co-doped ternary cathode material, includes the following steps:

[0087] (1) Prepare the precursor Ni according to conventional methods. 0.63 Co 0.09 Mn 0.28 (OH)2(D 50 (11.5±0.5μm), Li2CO3 (D) 50 (6±2 μm) and dopant ZrF4 (D 50 (5±2μm) and θ-Al2O3 (D 50 (5±2μm) raw materials, weigh Ni respectively 0.63 Co 0.09 Mn 0.28 (OH)2 (2000g), Li2CO3 (844.97g), ZrF4 (8.4405g), and θ-Al2O3 (7.5658g) were mixed uniformly in a high-speed mixer using a three-stage mixing process: 200 rpm / 2 min, 800 rpm / 20 min, and 100 rpm / 3 min. The mixture was then placed in a crucible and transferred to a muffle furnace under a slightly positive pressure oxygen atmosphere. The temperature was increased to 460℃ at a rate of 3℃ / min for 4.0 h, then increased to 710℃ for 4.0 h, and finally increased to 945℃ for 12.0 h. After cooling, the mixture was crushed and sieved to obtain the ternary cathode material doped matrix.

[0088] (2) 1600g of ternary cathode material doped substrate and coating agent B4C (D 50 (50±20nm) (1.8421g) and γ-Al2O3 (D 50 The three powders (40±20nm) (2.1184g) were put into a high-speed mixer and mixed evenly in three stages: 100rpm / 2min, 1200rpm / 30min, and 200rpm / 3min. The mixture was then placed into a crucible and sintered at 530℃ for 8.0h in a dry air atmosphere. After cooling, the mixture was crushed and then sieved to remove magnetism, thus obtaining the coated matrix.

[0089] (3) Take 1500g of the obtained coating substrate and mix it with the additive α-Al2O3 (D 50 The three powders (40±20nm) (2.1184g) were put into a high-speed mixer and mixed in three stages: 100rpm / 2min, 1000rpm / 30min, and 200rpm / 3min. After the three powders were mixed evenly, they were put into a crucible and sintered at 350℃ for 6.0h in a dry air atmosphere. After cooling, they were crushed and then sieved to remove magnetism. The resulting ternary cathode material was put into a batch mixing tank and mixed for 2h. After discharge, the material was sieved to remove magnetism and packaged to obtain the finished ternary cathode material. The relevant physicochemical data were tested.

[0090] Comparative Example 1

[0091] The preparation method of the ternary cathode material described in this comparative example includes the following steps:

[0092] (1) Prepare the precursor Ni according to conventional methods. 0.83 Co 0.11 Mn 0.06 (OH)2(D 50 (3.6±0.5μm), LiOH·H2O (D) 50 (6±2 μm) and dopant ZrF4 (D 50 (5±2μm) and θ-Al2O3 (D 50 (5±2μm) raw materials; weigh Ni 0.83 Co 0.11 Mn 0.06(OH)2 (2000g), LiOH·H2O (945.02g), θ-Al2O3 (6.8092g); the above materials were transferred to a high-speed mixer and mixed evenly using a three-stage mixing mode of 200rpm / 2min, 800rpm / 20min, and 100rpm / 3min. After being loaded into a crucible, the mixture was transferred to a muffle furnace and sintered at 460℃ for 4.0h under a slightly positive pressure oxygen atmosphere at a rate of 3℃ / min, followed by heating to 710℃ for 4.0h, and then heating to 880℃ for 12.0h. After cooling, crushing and sieving, the ternary cathode material doped matrix was obtained.

[0093] (2) The obtained doped substrate was washed with water at a water-to-material ratio of 1:1.5 for 30 seconds, vacuum filtered, and then dried in a vacuum oven at 150℃ for 6 hours. 1600g of the sample was then mixed with the additive γ-Al2O3 (D 50 The three powders (40±20nm) (2.4211g) were put into a high-speed mixer and mixed evenly in three stages: 100rpm / 2min, 1200rpm / 30min, and 200rpm / 3min. The mixture was then placed into a crucible and sintered at 530℃ for 8.0h under an oxygen atmosphere. After cooling, the mixture was crushed and then demagnetized by sieving to obtain the ternary cathode material coating matrix.

[0094] (3) Take 1500g of the obtained coating substrate and mix it with the additive α-Al2O3 (D 50 The three powders (40±20nm) (1.1858g) were put into a high-speed mixer and mixed evenly in three stages: 100rpm / 2min, 1000rpm / 30min, and 200rpm / 3min. The mixture was then placed into a crucible and sintered at 350℃ for 5.0h in an oxygen or oxygen-air (5:5) atmosphere. After cooling, the mixture was crushed and then sieved to remove magnetism. The resulting ternary cathode material was put into a batch mixing tank and mixed for 2h. The discharged material was sieved to remove magnetism and packaged to obtain the finished ternary cathode material. The relevant physicochemical data were then tested.

[0095] Comparative Example 2

[0096] The preparation method of the ternary cathode material described in this comparative example includes the following steps:

[0097] (1) Prepare the precursor Ni according to conventional methods. 0.83 Co 0.11 Mn 0.06 (OH)2(D 50 (12±1μm), LiOH·H2O (D) 50 (6±2 μm) and dopant ZrF4 (D 50 (5±2μm) and θ-Al2O3 (D 50 (5±2μm) raw materials; weigh Ni0.83 Co 0.11 Mn 0.06 (OH)2 (2000g), LiOH·H2O (945.02g), θ-Al2O3 (6.8092g); the materials were transferred to a high-speed mixer and mixed evenly using a three-stage mixing process of 200rpm / 2min, 800rpm / 20min, and 100rpm / 3min. The mixture was then placed in a crucible and transferred to a muffle furnace. Under a slightly positive pressure oxygen atmosphere, the temperature was increased to 460℃ at a rate of 3℃ / min and held for 4.0h. The temperature was then increased to 710℃ and sintered for 4.0h. Finally, the temperature was increased to 865℃ and sintered for 12.0h. After cooling, the mixture was crushed and sieved to obtain the ternary cathode material doped matrix.

[0098] (2) The obtained doped substrate was washed with water at a water-to-material ratio of 1:1.5 for 30 seconds, vacuum filtered, and then dried in a vacuum oven at 150℃ for 6 hours. 1600g of the sample was then mixed with the coating agent γ-Al2O3 (D 50 The three powders (40±20nm) (2.4211g) were put into a high-speed mixer and mixed in three stages: 100rpm / 2min, 1200rpm / 30min, and 200rpm / 3min. After the three powders were mixed evenly, they were put into a crucible and sintered at 480℃ for 8.0h in an oxygen atmosphere. After cooling, they were crushed and then sieved to remove magnetism, thus obtaining the ternary cathode material coated matrix.

[0099] (3) Take 1500g of the obtained substrate and mix it with the additive α-Al2O3 (D 50 The three powders (40±20nm) (1.1858g) were put into a high-speed mixer and mixed in three stages: 100rpm / 2min, 1000rpm / 30min, and 200rpm / 3min. After the three powders were mixed evenly, they were put into a crucible and sintered at 350℃ for 5.0h in an oxygen-air (5:5) atmosphere. After cooling, the mixture was crushed and then sieved to remove magnetism. The resulting ternary cathode material was put into a batch mixing tank and mixed for 2h. After discharge, the material was sieved to remove magnetism and packaged to obtain the finished ternary cathode material. The relevant physicochemical data were tested.

[0100] Comparative Example 3

[0101] The preparation method of the ternary cathode material described in this comparative example includes the following steps:

[0102] (1) Prepare the precursor Ni according to conventional methods. 0.63 Co 0.09 Mn 0.28 (OH)2(D 50 (3.8±0.5μm), Li2CO3 (D 50 (6±2 μm) and dopant ZrF4 (D 50 (5±2μm) and θ-Al2O3 (D50 (5±2μm) raw materials; weigh Ni 0.63 Co 0.09 Mn 0.28 (OH)2 (2000g), Li2CO3 (844.97g), ZrF4 (8.4405g), θ-Al2O3 (7.5658g); the materials were transferred to a high-speed mixer and mixed uniformly using a three-stage mixing process of 200 rpm / 2min, 800 rpm / 20min, and 100 rpm / 3min. The mixture was then placed in a crucible and transferred to a muffle furnace under a slightly positive pressure oxygen atmosphere. The temperature was increased to 460℃ at a rate of 3℃ / min and sintered for 4.0h, then increased to 710℃ and sintered for 4.0h, and then increased to 970℃ and sintered for 12.0h. After cooling, the mixture was crushed and sieved to obtain the ternary cathode material doped matrix.

[0103] (2) 1600g of ternary cathode material doped substrate and coating agent B4C (D 50 (50±20nm) (1.8421g) and γ-Al2O3 (D 50 The three powders (40±20nm) (2.1184g) were put into a high-speed mixer and mixed evenly in three stages: 100rpm / 2min, 1200rpm / 30min, and 200rpm / 3min. The mixture was then placed into a crucible and sintered at 530℃ for 8.0h in a dry air atmosphere. After cooling, the mixture was crushed and then sieved to remove magnetism, thus obtaining the ternary cathode material coated matrix.

[0104] (3) Take 1500g of the obtained coating substrate and mix it with the additive α-Al2O3 (D 50 The three powders (40±20nm) (2.1184g) were put into a high-speed mixer and mixed in three stages: 100rpm / 2min, 1000rpm / 30min, and 200rpm / 3min. After the three powders were mixed evenly, they were put into a crucible and sintered at 350℃ for 6.0h in a dry air atmosphere. After cooling, they were crushed and then sieved to remove magnetism. The resulting ternary cathode material was put into a batch mixing tank and mixed for 2h. After discharge, the material was sieved to remove magnetism and packaged to obtain the finished ternary cathode material. The relevant physicochemical data were tested.

[0105] Comparative Example 4

[0106] The preparation method of the ternary cathode material described in this comparative example includes the following steps:

[0107] (1) Prepare the precursor Ni according to conventional methods. 0.63 Co 0.09 Mn 0.28 (OH)2(D 50 (11.5±0.5μm), Li2CO3 (D) 50 (6±2 μm) and dopant ZrF4 (D50 (5±2μm) and θ-Al2O3 (D 50 (5±2μm) raw materials; weigh Ni 0.63 Co 0.09 Mn 0.28 (OH)2 (2000g), Li2CO3 (844.97g), ZrF4 (8.4405g), and θ-Al2O3 (7.5658g) were mixed uniformly in a high-speed mixer using a three-stage mixing process: 200 rpm / 2 min, 800 rpm / 20 min, and 100 rpm / 3 min. The mixture was then placed in a crucible and transferred to a muffle furnace. Under a slightly positive pressure oxygen atmosphere, the temperature was increased to 460℃ at a rate of 3℃ / min and sintered for 4.0 h. The temperature was then increased to 710℃ and sintered for 4.0 h. Finally, the temperature was increased to 960℃ and sintered for 12.0 h. After cooling, the mixture was crushed and sieved to obtain the ternary cathode material doped matrix.

[0108] (2) 1600g of ternary cathode material doped matrix and coating agent γ-Al2O3 (D 50 The three powders (40±20nm) (2.1184g) were put into a high-speed mixer and mixed in three stages: 100rpm / 2min, 1200rpm / 30min, and 200rpm / 3min. After the three powders were mixed evenly, they were put into a crucible and sintered at 530℃ for 8.0h in a dry air atmosphere. After cooling, they were crushed and then sieved to remove magnetism, thus obtaining the ternary cathode material coating matrix.

[0109] (3) Take 1500g of the obtained coating substrate and mix it with the additive α-Al2O3 (D 50 The three powders (40±20nm) (2.1184g) were put into a high-speed mixer and mixed in three stages: 100rpm / 2min, 1000rpm / 30min, and 200rpm / 3min. After the three powders were mixed evenly, they were put into a crucible and sintered at 350℃ for 6.0h in a dry air atmosphere. After cooling, they were crushed and then sieved to remove magnetism. The resulting ternary cathode material was put into a batch mixing tank and mixed for 2h. After discharge, the material was sieved to remove magnetism and packaged to obtain the finished ternary cathode material. The relevant physicochemical data were tested.

[0110] Experimental Example

[0111] 1. Physicochemical Indicators

[0112] The physicochemical properties of the ternary cathode materials prepared in Examples 1-4 and Comparative Examples 1-4 were analyzed using equipment familiar to technicians, such as scanning electron microscopes, laser particle size analyzers, and automatic titration instruments from Metrohm, Switzerland. The test results are shown in Table 1 below.

[0113] SEM images of the ternary cathode materials prepared in Examples 1-4 are attached. Figure 2 As shown in (a)-(d).

[0114] Table 1. Physicochemical properties of ternary cathode materials in Examples 1-4 and Comparative Examples 1-4

[0115]

[0116] As can be seen from the test data of the basic material physicochemical properties of Ni83 and Ni63 ternary cathode polycrystalline and single-crystal materials in Examples 1-4, the relevant tap and residual alkali content performance indicators have been improved, demonstrating superior performance advantages.

[0117] 2. Cyclic performance test

[0118] Using methods well known to those skilled in the art, the cathode materials prepared in Examples 1-4 and Comparative Examples 1-4 were respectively prepared into lithium-ion battery schemes (active material: PVDF: CNT: SP = 97.2: 1.1: 0.8: 0.9, solid content 73.5%), and the obtained cathode materials were assembled into coin cells.

[0119] Using the Blue Electric testing system, the initial charge-discharge specific capacity and discharge performance at 0.2C / 0.5C / 1.0C / 2.0C rates were measured at 25℃ and 0.1C under the voltage range of 3.0-4.35V. The results are shown in Table 2 below.

[0120] Table 2 Results of Discharge Performance Tests at Higher Rates

[0121]

[0122] The cycle retention rate after 100 cycles was tested under 1C charge / discharge conditions, and the test results are shown below. Figure 3 As shown, where, Figure 3 In the middle (a)-(d), the control results of Examples 1-4 and Comparative Examples 1-4 are respectively.

[0123] The finished products obtained in Example 3 and Comparative Example 3 were used to prepare soft-pack battery cells, and their cycling performance was evaluated at room temperature and high temperature. The test results at different temperatures are shown in the attached figure. Figure 4-5 As shown in Table 3, the cyclic DCIR test data of the product in Example 3 are shown below.

[0124] Table 3. Results of product cycle DCIR test in Example 3

[0125]

[0126] It is evident that the ternary cathode material prepared based on this doping and coating formulation and process system exhibits excellent low DCIR performance and long cycling performance at both room temperature and high temperature. In Example 3, the ternary cathode material product maintains over 91% capacity after continuous room temperature cycling for 1200 @ at 1C / 1C-100% DOD (2.75V-4.30V) and over 85% capacity after 1200 @ at high temperature, with low DCIR growth.

[0127] The embodiments of the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for preparing a boron-coated fluorine-zirconium co-doped ternary cathode material, characterized in that, The ternary cathode material has properties such as LiNi. x Co y Mn z Zr a Al b B c F d O 2-d The general formula shown is x+y+z+a+b+c+d=1; The method includes the following steps: (1) Take Ni, the precursor of ternary cathode material, according to the selected content ratio. x Co y Mn z (OH)2, lithium source material and fluorine-containing zirconium dopant are mixed and subjected to a first sintering treatment to obtain a ternary cathode material doped matrix; The ternary cathode material precursor Ni x Co y Mn z (OH)2, the molar ratio of the lithium source material and the fluorinated zirconium dopant is 1:(0.96-1.30):(0.02-1.0); The fluorinated zirconium dopant comprises a mixture of ZrF4 and θ-Al2O3; wherein, The ternary cathode material precursor Ni x Co y Mn z The mass ratio of (OH)2 to ZrF4 is 100:(0.05-1.0). The ternary cathode material precursor Ni x Co y Mn z The mass ratio of (OH)2 to θ-Al2O3 is 100:(0.05-0.6). (2) The ternary cathode material doped matrix is ​​mixed with the boron-containing coating agent according to the selected content ratio, and a second sintering treatment is performed to obtain the ternary cathode material coated matrix; the molar ratio of the ternary cathode material doped matrix to the boron-containing coating agent is 1:(0.02-0.3). The boron-containing coating agent comprises a mixture of B4C and γ-Al2O3; (3) According to the selected content ratio, the ternary cathode material coating matrix is ​​mixed with aluminum-containing additives and subjected to a third sintering treatment to obtain the desired boron-coated fluorine-zirconium co-doped ternary cathode material.

2. The method for preparing the boron-coated fluorine-zirconium co-doped ternary cathode material according to claim 1, characterized in that, In step (1): The lithium source material includes one or a mixture of several of LiOH, LiOH·H2O, Li2CO3 or LiNO3.

3. The method for preparing the boron-coated fluorine-zirconium co-doped ternary cathode material according to claim 2, characterized in that, In step (1), the first sintering step includes: a first heating to 400-500℃ and holding for 2-6 hours in an oxygen-containing atmosphere, a second heating to 580-740℃ and holding for 2-5 hours, and a third heating to 740-970℃ and holding for 6-24 hours.

4. The method for preparing the boron-coated fluorine-zirconium co-doped ternary cathode material according to claim 3, characterized in that, In step (1), when the first sintering step is carried out in a muffle furnace or tube furnace mode, the heating rates of the first heating, second heating and third heating steps are controlled to be 1-5℃ / min, which are independent of each other.

5. The method for preparing the boron-coated fluorine-zirconium co-doped ternary cathode material according to claim 3, characterized in that, In step (1), when the first sintering step is carried out in atmosphere roller kiln or rotary kiln mode, the heating rate of the first heating step, the second heating step and the third heating step are controlled to be independent of each other and are 1-30℃ / h.

6. The method for preparing the boron-coated fluorine-zirconium co-doped ternary cathode material according to claim 1, characterized in that, In step (2): in, The mass ratio of the ternary cathode material doped matrix to the B4C is 100:(0.05-0.25). The mass ratio of the ternary cathode material doped matrix to the γ-Al2O3 is 100:(0.08-0.3).

7. The method for preparing the boron-coated fluorine-zirconium co-doped ternary cathode material according to claim 6, characterized in that, In step (2), the second sintering step includes heating to 350-720℃ for calcination and holding at that temperature for 1-24 hours.

8. The method for preparing the boron-coated fluorine-zirconium co-doped ternary cathode material according to claim 7, characterized in that, In step (2), the second sintering step is controlled to have a heating rate of 1-20℃ / h.

9. The method for preparing the boron-coated fluorine-zirconium co-doped ternary cathode material according to claim 8, characterized in that, In step (2), when the molar content of Ni element x in the ternary cathode material doped matrix is ​​≥0.8, before adding the boron-containing coating agent, the step of dispersing, washing and drying the ternary cathode material doped matrix is ​​also included.

10. The method for preparing the boron-coated fluorine-zirconium co-doped ternary cathode material according to claim 1, characterized in that, In step (3), the aluminum-containing additive includes α-Al2O3; The mass ratio of the ternary cathode material coating matrix to the α-Al2O3 is 100:(0.05-0.20).

11. The method for preparing the boron-coated fluorine-zirconium co-doped ternary cathode material according to claim 10, characterized in that, In step (3), the third sintering step includes heating to 200-400℃ for calcination and holding at that temperature for 1-10 hours.

12. The method for preparing the boron-coated fluorine-zirconium co-doped ternary cathode material according to claim 11, characterized in that, In step (3), the heating rate is controlled to be 1-20℃ / h in the third sintering step.

13. The method for preparing the boron-coated fluorine-zirconium co-doped ternary cathode material according to claim 10, characterized in that, Step (3) further includes crushing, sieving, and demagnetizing the obtained boron-coated fluorine-zirconium co-doped ternary cathode material.

14. The method for preparing the boron-coated fluorine-zirconium co-doped ternary cathode material according to claim 10, characterized in that, In step (3), the large particle size D of the boron-coated fluorine-zirconium co-doped ternary cathode material is... 50 The particle size D of the small particle matrix is ​​9-16 μm. 50 The range is 2.5-6.0 μm.

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