High-stability high-nickel ternary positive electrode material based on cationic lattice self-adaptive anchoring

Abstract

The structural general formula of the high-nickel ternary positive electrode material is LiNixCoyMzO2 (M is Al or Mn), x is larger than or equal to 0.60 and smaller than 1.00, y is larger than or equal to 0.02 and smaller than or equal to 0.40, z is larger than or equal to 0.01 and smaller than or equal to 0.40, and x + y + z is equal to 1. Aiming at the problems of structure collapse and performance degradation caused by cation mixing generated in an electrochemical cycle process of a traditional high-nickel ternary positive electrode material, Ni < 2 + > anchoring sites periodically distributed in a lithium layer are accurately constructed by adjusting a gradient lithium ratio-metal pinning effect coupling process; ni < 2 + > is induced to generate directional migration along a [001] crystal orientation by utilizing a lithium concentration gradient, and disordered diffusion is limited through a pinning effect of inert ions. A part of Ni < 2 + > can occupy a lithium layer site, the heterostructure serves as a pillar in a lithium layer, a steric hindrance effect is formed by providing electrostatic repulsive force, and a dynamic barrier for inhibiting transition metal ion migration is constructed, so that positive ion mixing aggravation caused by further migration of transition metal ions to the lithium site is prevented. Through the lattice self-adaptive anchoring engineering, the cation mixing degree generated in the electrochemical cycle process is reduced, so that the structural stability of the material is improved at low cost, and the electrochemical performance is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium-ion battery positive electrode materials, and specifically relates to a high-nickel ternary positive electrode material with a lattice cation adaptive anchoring structure, and further discloses a preparation process and application thereof. Background Art

[0002] As "carbon neutrality" becomes a global consensus, traditional companies that mainly rely on fossil fuel consumption are being forced to transform and upgrade. For example, in the automotive field, due to the presence of high-efficiency conversion devices, the total conversion efficiency of electric vehicles (EVs) is higher than that of gasoline vehicles. As a typical renewable energy storage technology, lithium-ion batteries (LIBs) have surpassed traditional lead-acid and nickel-hydrogen systems in terms of energy density, power density and cycle performance, and their advantages are becoming more and more obvious with continuous development. Compared with the rapid development of high-energy-density anode materials (such as silicon, lithium metal, etc.), the progress of positive electrode materials is obviously limited, which greatly restricts the overall performance of lithium-ion batteries. In addition, the positive electrode material currently accounts for about 42% of the total battery cost, while the negative electrode material accounts for only 12%, which makes the development of cost-effective positive electrode materials more urgent than ever.

[0003] Over the past three decades, layered oxides (LiMO 2 , M = Ni, Co, Mn), spinel oxide (LiM 2 O 4 , M = Mn, Ni, Co), olivine salt (LiFePO 4 、LiFe x Mn 1-x PO 4 ) and lithium-rich manganese-based materials (xLi 2 MnO 3 ·(1-x) LiMO 2 , M = Ni, Co, Mn) and other materials are being explored to explore high-capacity and high-voltage cathode materials. However, increasing the energy density of the cathode will inevitably reduce the electrochemical stability of the cathode material. Among these different options, layered oxides offer the best combination of high capacity and high stability and are considered to be one of the most promising cathode materials for electric vehicles. In recent years, α-NaFeO 2 Common layered oxides with structures and R-3m space groups, such as LiNiO 2 (LNO)、LiCoO 2 (LCO), LiMnO 2 (LMO)、Li(Ni 1-x-y Co x Mn y ) 2 (NCM) and Li(Ni1-x-y Co x Al y ) 2 (NCA), etc., have been widely studied. Due to their high practical energy density and reasonable cost, ternary cathode materials NCM or NCA have become a research hotspot and are the most promising cathode materials for the next generation of high energy density lithium-ion batteries.

[0004] However, it seems that high specific capacity is always associated with low stability level, as the delithiated Li x MO 2 When the phase exceeds a certain limit, its stability will drop sharply. + (0.76 Å) and Ni 2+ The similar radius size (0.69 Å) easily induces lattice cation mixing in the NCA lattice structure. + / Ni 2+ Site replacement will compress the interlayer spacing of the lithium ion transmission channel, increase the lithium ion migration barrier, and be accompanied by harmful phenomena such as surface degradation, electrolyte oxidation and transition metal ion dissolution, resulting in poor capacity retention. Summary of the invention

[0005] In view of the above problems, the present invention provides a high-cost-effective high-stability high-nickel ternary cathode material based on cation lattice adaptive anchoring, which accurately constructs Ni periodically distributed in the lithium layer by adjusting the gradient lithium ratio-metal pinning effect coupling process. 2+ Anchoring sites, using lithium concentration gradient to induce Ni 2+ Directed migration occurs along the

[001] crystal direction, while disordered diffusion is limited by the pinning effect of inert ions. 2+ Able to occupy the lithium layer site, this heterostructure acts as a "pillar" in the lithium layer, forming a steric effect by providing electrostatic repulsion, and constructing a dynamic barrier to inhibit the migration of transition metal ions, so as to prevent the further migration of transition metal ions to the lithium site from causing the intensification of cation mixing. Through this lattice adaptive anchoring engineering, the degree of cation mixing that occurs during the electrochemical cycle is reduced, and the crystallinity is increased, thereby improving the structural stability of the material and improving the electrochemical performance.

[0006] In order to achieve the above-mentioned purpose of the invention, the technical scheme and steps adopted by the present invention are as follows:

[0007] The present invention provides a high-nickel ternary positive electrode material with a lattice cation adaptive anchoring structure and a laboratory preparation process thereof, wherein the general structural formula is LiNi x Co y M z O 2(M=Al, Mn), 0.60≤x<1.00, 0.02≤y≤0.40, 0.01≤z≤0.40, and x+y+z=1. The ternary positive electrode material is a secondary particle composed of primary particles, the particle size of the primary particles is 10-80 nm, the D50 particle size of the ternary positive electrode material is 2-10 μm, and the specific surface area of ​​the ternary positive electrode material is 15-60 m 2 / g. The specific preparation process of the ternary positive electrode material comprises the following steps: Step 1: Weigh each metal salt according to the stoichiometric ratio of the target material and prepare the corresponding metal salt solution; Step 2: The metal salt solution in step 1 is introduced dropwise into a multi-mouth flask at a certain rate for heating and stirring to perform a coprecipitation reaction, and nitrogen is continuously introduced to maintain an inert atmosphere, and a precipitant and a complexing agent are added to control the pH value of the mixed solution, and a coprecipitation phase is obtained after a certain reaction time; Step 3: filtering and washing the coprecipitated phase obtained in step 2, and then transferring it to a vacuum oven for aging to obtain a precursor having a lattice cation adaptive anchoring structure; Step 4: Evenly mix the precursor obtained in step 3 with the lithium source, and sinter them in an oxygen atmosphere to obtain a ternary positive electrode material with a lattice cation adaptive anchoring structure.

[0008] In one or more technical schemes, the metal salts include nickel salts, cobalt salts, aluminum salts, and manganese salts, and can be divided into high-nickel ternary positive electrode materials prepared from nickel salts, cobalt salts and aluminum salts or from nickel salts, cobalt salts and manganese salts according to different technical schemes.

[0009] In one or more technical solutions, the nickel salt is one or more of nickel sulfate, nickel nitrate, nickel chloride, nickel acetate or their hydrates.

[0010] In one or more technical solutions, the cobalt source is one or more of cobalt sulfate, cobalt nitrate, cobalt chloride, cobalt acetate or their hydrates.

[0011] In one or more technical solutions, the aluminum source is one or more of aluminum sulfate, aluminum nitrate, aluminum chloride, aluminum acetate or their hydrates.

[0012] In one or more technical solutions, the manganese source is one or more of manganese sulfate, manganese nitrate, manganese chloride, manganese acetate or hydrates thereof.

[0013] In one or more technical solutions, the precipitant is sodium hydroxide (NaOH), sodium carbonate (Na 2 CO 3 ), sodium bicarbonate (NH 4 HCO 3 ), ammonia (NH4 OH), the complexing agent is ammonia (NH 4 OH).

[0014] In one or more technical solutions, the reaction temperature is controlled to be 40-90° C. by water bath heating, wherein the preferred reaction temperature is 50-80° C.

[0015] In one or more technical solutions, the stirring rate of the reaction is controlled to be 300-1000 rpm, wherein the preferred stirring rate is 500-800 rpm.

[0016] In one or more technical solutions, the dripping rate of the metal salt solution and the complexing agent is controlled at 2-6 mL / min, and the dripping rate of the precipitant is adjusted in real time according to the pH value of the reaction environment. Among them, the preferred dripping rate is 3-5 mL / min.

[0017] In one or more technical solutions, the entire coprecipitation reaction is divided into three stages. In the first stage, the pH value is controlled between 10-11.8, and the reaction lasts for 1-4 hours; in the second stage, the pH value is controlled between 11.8-13, and the reaction lasts for 4-10 hours; in the third stage, the pH value is controlled between 10.5-11.8, and the reaction lasts for 2-6 hours. Preferably, the pH value is controlled between 10.5-11.5 in the first stage, and the reaction lasts for 2-4 hours; the pH value is controlled between 11.5-12.5 in the second stage, and the reaction lasts for 5-12 hours; and the pH value is controlled between 11.0-11.8 in the third stage, and the reaction lasts for 3-6 hours. The total reaction time is 12-22 hours.

[0018] In one or more technical solutions, the temperature of the aging process is 60-120°C, and the standing time is 6-30 hours. Preferably, the temperature of the aging process is 70-100°C, and the standing time is 12-24 hours.

[0019] In one or more technical solutions, the lithium source is lithium hydroxide (LiOH) lithium carbonate (Li 2 CO 3 )、LiNO 3 ) and one or more of its hydrates. Among them, LiOH·H 2 O and Li 2 CO 3 .

[0020] In one or more technical solutions, the entire sintering process needs to be divided into three stages. In the first stage, the temperature is raised to 400-650℃ and kept warm for 3-8 hours, and the heating rate is controlled at 3-5℃ / min; in the second stage, the temperature is raised to 700-950℃ and kept warm for 10-20 hours, and the heating rate is controlled at 1-2℃ / min; in the third stage, the temperature is lowered to 400-650℃, the cooling rate is controlled at 1-2℃ / min, and finally naturally cooled to room temperature. Among them, as a preferred embodiment, the first stage is heated to 400-600℃ and kept warm for 3-6 hours, and the heating rate is controlled at 3-5℃ / min; in the second stage, the temperature is raised to 700-900℃ and kept warm for 12-18 hours, and the heating rate is controlled at 1-2℃ / min; in the third stage, the temperature is lowered to 400-600℃, and the cooling rate is controlled at 1-2℃ / min.

[0021] In one or more technical solutions, the obtained high nickel ternary cathode material having a lattice cation adaptive anchoring structure has a general structural formula of LiNi x Co y M z O 2 (M=Al, Mn), 0.60≤x<1.00, 0.02≤y≤0.40, 0.01≤z≤0.40, x+y+z=1. Preferably, 0.80≤x≤0.95, 0.05≤y≤0.20, 0.08≤z≤0.25.

[0022] In addition, the present invention also provides a simple application of a battery assembled with a high nickel ternary cathode material (Modified sample) having a lattice cation adaptive anchoring structure, and compares it with a battery assembled with a traditional high nickel ternary cathode material (Pure sample) having the same stoichiometric ratio. The half-cell of the uniform assembly model is CR2016, with the prepared material pole piece as the positive electrode, 1 mm metal lithium as the negative electrode, the separator is the polyethylene separator (PE) of Celgard in the United States, and the electrolyte is the commercial electrolyte LB-002 (1.0M LiPF6 dissolved in EC:DMC:EMC=1:1:1 vol% mixed solution).

[0023] After simple XRD structural characterization and 1C long cycle electrochemical test, it is proved that the high nickel ternary cathode material prepared by lattice adaptive anchoring engineering has a higher cation mixing degree before electrochemical cycle. This conclusion can be obtained from XRD spectrum analysis. This is due to the special process regulation. 2+ Orderly and adaptively occupy some lithium layer sites and form an anchoring structure, acting as a "pillar" in the lithium layer. However, such a "pillar Ni 2+"By providing electrostatic repulsion to form a steric effect, a dynamic barrier is constructed to inhibit the migration of transition metal ions, so as to prevent the further migration of transition metal ions to the lithium site during the electrochemical cycle, which will lead to the intensification of cation mixing, thereby having better structural stability and electrochemical stability, which is also consistent with the results of electrochemical tests. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only part of the embodiments of the present invention. For ordinary technicians in this field, they can also obtain drawings of other parts of the embodiments based on these drawings without creative work.

[0025] Figure 1 1 is a schematic diagram comparing the XRD characterization results of the high nickel ternary cathode material with lattice cation adaptive anchoring structure prepared in Example 1 of the present invention and the traditional high nickel ternary cathode material with the same stoichiometric ratio. Researchers usually use the diffraction peak intensity ratio of (003) to (104) I （003） / I （104） As a key indicator for evaluating the degree of cation mixing in ternary cathode materials, the larger the ratio, the less mixing the transition metal cations occupying the lithium sites. This proves that the high nickel ternary cathode material prepared by lattice adaptive anchoring engineering has a higher degree of cation mixing before electrochemical cycling.

[0026] Figure 2 The figure is a schematic diagram comparing the charge-discharge cycle curves of the high-nickel ternary cathode material with lattice cation adaptive anchoring structure prepared in Example 1 of the present invention and the traditional high-nickel ternary cathode material with the same stoichiometric ratio. The voltage range is set at 3-4.3V, and a 1C charge-discharge cycle is performed at room temperature (25°C). It can be seen that the first cycle discharge specific capacity of the modified sample prepared by the adaptive anchoring method at 0.1C is slightly lower than that of the traditional ternary cathode material (Pure sample: 208.8 mAh g -1 ; Modified sample: 207.2 mAh g -1 ), which is a sample with an adaptive anchoring structure with a slightly higher degree of lithium ion mixing than the sample material prepared by the traditional preparation method. After 100 1C charge and discharge cycles, the high nickel ternary cathode material with a lattice cation adaptive anchoring structure showed a higher discharge specific capacity (Puresample: 163.2 mAh g -1 ; Modified sample: 170.1 mAh g -1), compared with the traditional high-nickel ternary positive electrode material, the cycle capacity retention rate is increased from 83.7% to 87.5%. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0028] In order to further understand the present invention, the preferred embodiments of the present invention are described below. However, it should be understood that these descriptions exist only to further illustrate the features and advantages of the present invention and are not intended to limit the claims of the present invention. The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0029] The theories or mechanisms described and disclosed in this article, whether right or wrong, should not limit the scope of the present invention in any way. The present invention can also be implemented or applied through other different specific implementation methods. The details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0030] Herein, when describing embodiments or examples, it should be understood that they are not used to limit the present invention to these embodiments or examples. On the contrary, all substitutes, improvements and equivalents of the methods and materials described in the present invention can be included in the scope limited by the claims.

[0031] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0032] Example

[0033] A high nickel ternary cathode material with a lattice cation adaptive anchoring structure, the general structural formula of which is LiNi x Co y M z O 2(M=Al, Mn), 0.60≤x<1.00, 0.02≤y≤0.40, 0.01≤z≤0.40, and x+y+z=1. The ternary positive electrode material is a secondary particle composed of primary particles, the particle size of the primary particles is 10-80 nm, the particle size D50 of the ternary positive electrode material is 2-10 μm, and the specific surface area of ​​the ternary positive electrode material is 15-60 m 2 / g. The specific preparation process of the ternary positive electrode material comprises the following steps: Step 1: Weigh each metal salt according to the stoichiometric ratio of the target material and prepare the corresponding metal salt solution; Step 2: The metal salt solution in step 1 is introduced dropwise into a multi-mouth flask at a certain rate for heating and stirring to perform a coprecipitation reaction, and nitrogen is continuously introduced to maintain an inert atmosphere, and a precipitant and a complexing agent are added to control the pH value of the mixed solution, and a coprecipitation phase is obtained after a certain reaction time; Step 3: filtering and washing the coprecipitated phase obtained in step 2, and then transferring it to a vacuum oven for aging to obtain a precursor having a lattice cation adaptive anchoring structure; Step 4: Evenly mix the precursor obtained in step 3 with the lithium source, and sinter them in an oxygen atmosphere to obtain a ternary positive electrode material with a lattice cation adaptive anchoring structure.

[0034] In an embodiment, the metal salt includes nickel salt, cobalt salt, aluminum salt, and manganese salt, and can be divided into high-nickel ternary positive electrode materials prepared from nickel salt, cobalt salt and aluminum salt or from nickel salt, cobalt salt and manganese salt according to different technical schemes.

[0035] In an embodiment, the nickel salt is one or more of nickel sulfate, nickel nitrate, nickel chloride, nickel acetate or hydrates thereof.

[0036] In an embodiment, the cobalt source is one or more of cobalt sulfate, cobalt nitrate, cobalt chloride, cobalt acetate or hydrates thereof.

[0037] In an embodiment, the aluminum source is one or more of aluminum sulfate, aluminum nitrate, aluminum chloride, aluminum acetate or hydrates thereof.

[0038] In an embodiment, the manganese source is one or more of manganese sulfate, manganese nitrate, manganese chloride, manganese acetate or hydrates thereof.

[0039] In the embodiment, the precipitant is sodium hydroxide (NaOH), sodium carbonate (Na 2 CO 3 ), ammonium bicarbonate (NH 4 HCO 3 ), ammonia (NH 4 OH), the complexing agent is ammonia (NH4 OH).

[0040] In the embodiment, the reaction temperature is controlled to be 40-90°C by water bath heating, wherein the preferred reaction temperature is 50-80°C.

[0041] In an embodiment, the stirring rate of the reaction is controlled to be 300-1000 rpm, wherein the preferred stirring rate is 500-800 rpm.

[0042] In the embodiment, the dropping rate of the metal salt solution and the complexing agent is controlled at 2-6 mL / min, and the dropping rate of the precipitant is adjusted in real time according to the pH value of the reaction environment. Among them, the preferred dropping rate is 3-5 mL / min.

[0043] In the embodiment, the entire coprecipitation reaction is divided into three stages. In the first stage, the pH value is controlled between 10-11.8, and the reaction lasts for 1-4 h; in the second stage, the pH value is controlled between 11.8-13, and the reaction lasts for 4-10 h; in the third stage, the pH value is controlled between 10.5-11.8, and the reaction lasts for 2-6 h. Preferably, the pH value is controlled between 10.5-11.5 in the first stage, and the reaction lasts for 2-4 h; the pH value is controlled between 11.5-12.5 in the second stage, and the reaction lasts for 5-12 h; the pH value is controlled between 11.0-11.8 in the third stage, and the reaction lasts for 3-6 h. The total reaction time is 12-22 h.

[0044] In the embodiment, the temperature of the aging process is 60-120°C, and the standing time is 6-30 hours. Preferably, the temperature of the aging process is 70-100°C, and the standing time is 12-24 hours.

[0045] In the embodiment, the lithium source is lithium hydroxide (LiOH) lithium carbonate (Li 2 CO 3 )、LiNO 3 ) and one or more of its hydrates. Among them, LiOH·H 2 O and Li 2 CO 3 .

[0046] In the embodiment, the entire sintering process needs to be divided into three stages. In the first stage, the temperature is raised to 400-650℃ and kept warm for 3-8 hours, and the heating rate is controlled at 3-5℃ / min; in the second stage, the temperature is raised to 700-950℃ and kept warm for 10-20 hours, and the heating rate is controlled at 1-2℃ / min; in the third stage, the temperature is lowered to 400-650℃, the cooling rate is controlled at 1-2℃ / min, and finally naturally cooled to room temperature. Among them, as a preferred embodiment, the first stage is heated to 400-600℃ and kept warm for 3-6 hours, and the heating rate is controlled at 3-5℃ / min; in the second stage, the temperature is raised to 700-900℃ and kept warm for 12-18 hours, and the heating rate is controlled at 1-2℃ / min; in the third stage, the temperature is lowered to 400-600℃, and the cooling rate is controlled at 1-2℃ / min.

[0047] In the embodiment, the obtained high nickel ternary cathode material having a lattice cation adaptive anchoring structure has the general structure formula of LiNi x Co y M z O 2 (M=Al, Mn), 0.60≤x<1.00, 0.02≤y≤0.40, 0.01≤z≤0.40, x+y+z=1. Preferably, 0.80≤x≤0.95, 0.05≤y≤0.20, 0.08≤z≤0.25.

[0048] Example 1

[0049] A high nickel ternary cathode material (NCA) with a lattice cation adaptive anchoring structure, the general structure of which is LiNi 0.8 Co 0.15 Al 0.05 O 2 The ternary positive electrode material is a secondary particle composed of primary particles, the particle size of the primary particles is 10-80 nm, the particle size D50 of the ternary positive electrode material is 2-10 μm, and the specific surface area of ​​the ternary positive electrode material is 15-60 m 2 / g. The specific preparation process of the ternary positive electrode material comprises the following steps: Step 1: Nickel acetate (Ni(CH 3 COO 2 ), cobalt acetate (Co(CH 3 COO 2 ), aluminum acetate (Al(CH 3 COO 3 ) Weigh the drugs according to the stoichiometric ratio of 80:15:5 and prepare the corresponding metal salt solution; Step 2: Add the metal salt solution in step 1 dropwise into the multi-necked flask at a rate of 3-5 mL / min, heat and stir at 60°C and 600 rpm for coprecipitation reaction, and continue to introduce nitrogen to maintain an inert atmosphere. At the same time, add ammonium bicarbonate (NH 4 HCO 3 ) and ammonia (NH 4 OH) to control the pH value of the mixed solution. In the first stage, the pH value is controlled between 10.5-11.5, and the reaction lasts for 2-4 hours; in the second stage, the pH value is controlled between 11.5-12.5, and the reaction lasts for 5-12 hours; in the third stage, the pH value is controlled between 11.0-11.8, and the reaction lasts for 3-6 hours. After reacting for 20 hours, the coprecipitation phase is obtained; Step 3: filtering and washing the coprecipitated phase obtained in step 2, and then transferring it to a vacuum oven for aging to obtain a precursor having a lattice cation adaptive anchoring structure; Step 4: Mix the precursor prepared in step 3 with water and lithium hydroxide (LiOH·H 2 O) were mixed evenly and sintered in an oxygen atmosphere. In the first stage, the temperature was raised to 500°C and kept for 5 h, and the heating rate was controlled at 3°C / min; in the second stage, the temperature was raised to 770°C and kept for 15 h, and the heating rate was controlled at 2°C / min; in the third stage, the temperature was lowered to 500°C, the cooling rate was controlled at 2°C / min, and finally cooled naturally to room temperature. A ternary cathode material with a lattice cation adaptive anchoring structure was obtained.

[0050] Example 2

[0051] A high nickel ternary cathode material (NCM) with a lattice cation adaptive anchoring structure, the general structure of which is LiNi 0.8 Co 0.1 Mn 0.1 O 2 The ternary positive electrode material is a secondary particle composed of primary particles, the particle size of the primary particles is 10-80 nm, the particle size D50 of the ternary positive electrode material is 2-10 μm, and the specific surface area of ​​the ternary positive electrode material is 15-60 m 2 / g. The specific preparation process of the ternary positive electrode material comprises the following steps: Step 1: Nickel sulfate hexahydrate (NiSO 4 6H 2 O), cobalt sulfate heptahydrate (CoSO 4 7H 2 O), manganese sulfate tetrahydrate (MnSO 4 ·4H 2 O) Weigh the drugs according to the stoichiometric ratio of 8:1:1 and prepare the corresponding metal salt solution; Step 2: Add the metal salt solution in step 1 dropwise into the multi-necked flask at a rate of 3-5 mL / min, heat and stir at 60°C and 500 rpm for coprecipitation reaction, and continue to introduce nitrogen to maintain an inert atmosphere. At the same time, add sodium carbonate (Na 2 CO 3 ) and ammonia (NH 4 OH) to control the pH value of the mixed solution. In the first stage, the pH value is controlled between 10.5-11.5, and the reaction lasts for 3-5 hours; in the second stage, the pH value is controlled between 11.5-12.5, and the reaction lasts for 6-14 hours; in the third stage, the pH value is controlled between 11.0-11.8, and the reaction lasts for 3-5 hours. After reacting for 24 hours, the coprecipitation phase is obtained; Step 3: filtering and washing the coprecipitated phase obtained in step 2, and then transferring it to a vacuum oven for aging to obtain a precursor having a lattice cation adaptive anchoring structure; Step 4: Mix the precursor prepared in step 3 with water and lithium carbonate (Li 2 CO 3 ) are mixed evenly and sintered in an oxygen atmosphere. In the first stage, the temperature is raised to 550℃ and kept for 6 hours, and the heating rate is controlled at 3℃ / min; in the second stage, the temperature is raised to 800℃ and kept for 16 hours, and the heating rate is controlled at 2℃ / min; in the third stage, the temperature is lowered to 550℃, and the cooling rate is controlled at 3℃ / min, and finally cooled naturally to room temperature. A ternary cathode material with a lattice cation adaptive anchoring structure is obtained.

[0052] Comparative Example

[0053] In this comparative example, a NCA high-nickel ternary positive electrode material was prepared by a traditional method as a comparison with Example 1.

[0054] A high nickel ternary cathode material (NCA) with a lattice cation adaptive anchoring structure, the general structure of which is LiNi 0.8 Co 0.15 Al 0.05 O 2 The ternary positive electrode material is a secondary particle composed of primary particles, the particle size of the primary particles is 10-80 nm, the particle size D50 of the ternary positive electrode material is 2-10 μm, and the specific surface area of ​​the ternary positive electrode material is 15-60 m 2 / g. The specific preparation process of the ternary positive electrode material comprises the following steps: Step 1: Nickel acetate (Ni(CH 3 COO 2 ), cobalt acetate (Co(CH 3 COO 2), aluminum acetate (Al(CH 3 COO 3 ) Weigh the drugs according to the stoichiometric ratio of 80:15:5 and prepare the corresponding metal salt solution; Step 2: Add the metal salt solution in step 1 dropwise into the multi-necked flask at a rate of 3-5 mL / min, heat and stir at 60°C and 600 rpm for coprecipitation reaction, and continue to introduce nitrogen to maintain an inert atmosphere. At the same time, add ammonium bicarbonate (NH 4 HCO 3 ) and ammonia (NH 4 OH) to control the pH value of the mixed solution between 10.5 and 12.5, and obtain a coprecipitation phase after reacting for 20 h; Step 3: filtering and washing the coprecipitated phase obtained in step 2, and then transferring it to a vacuum oven for aging to obtain a precursor having a lattice cation adaptive anchoring structure; Step 4: Mix the precursor prepared in step 3 with water and lithium hydroxide (LiOH·H 2 O) were mixed evenly, and sintered in an oxygen atmosphere. In the first stage, the temperature was raised to 500°C and kept for 5 h, and the heating rate was controlled at 3°C / min; in the second stage, the temperature was raised to 770°C and kept for 15 h, and the heating rate was controlled at 2°C / min, and finally cooled naturally to room temperature. The comparative example ternary positive electrode material was obtained.

Claims

1. A high nickel ternary cathode material with a lattice cation adaptive anchoring structure, the preparation process of which comprises the following steps: Step 1: Weigh each metal salt according to the stoichiometric ratio of the target material and prepare the corresponding metal salt solution; Step 2: The metal salt solution in step 1 is introduced dropwise into a multi-mouth flask at a certain rate for heating and stirring to perform a coprecipitation reaction, and nitrogen is continuously introduced to maintain an inert atmosphere, and a precipitant and a complexing agent are added to control the pH value of the mixed solution, and a coprecipitation phase is obtained after a certain reaction time; Step 3: filtering and washing the coprecipitated phase obtained in step 2, and then transferring it to a vacuum oven for aging to obtain a precursor having a lattice cation adaptive anchoring structure; Step 4: Evenly mix the precursor obtained in step 3 with the lithium source, and sinter them in an oxygen atmosphere to obtain a ternary positive electrode material with a lattice cation adaptive anchoring structure.

2. The preparation method according to claim 1, characterized in that: The prepared high nickel ternary positive electrode material has the general structural formula of LiNi x Co y M z O2 (M = Al, Mn), 0.60 ≤ x < 1.00, 0.02 ≤ y ≤ 0.40, 0.01 ≤ z ≤ 0.40, and x + y + z = 1. The metal salt in step 1 includes nickel salt, cobalt salt, aluminum salt, and manganese salt, and can be divided into high nickel ternary positive electrode materials prepared from nickel salt, cobalt salt and aluminum salt or nickel salt, cobalt salt and manganese salt according to different technical solutions.

3. The preparation method according to claim 1, characterized in that: In step 2, the precipitant is one or more of sodium hydroxide (NaOH), sodium carbonate (Na2CO3), ammonium bicarbonate (NH4HCO3), and ammonia water (NH4OH), and the complexing agent is ammonia water (NH4OH).

4. The preparation method according to claim 1, characterized in that: In step 2, the reaction temperature is controlled to be 40-90° C. by water bath heating, wherein the preferred reaction temperature is 50-80° C.

5. The preparation method according to claim 1, characterized in that: In step 2, the stirring rate of the reaction is controlled to be 300-1000 rpm, wherein the preferred stirring rate is 500-800 rpm.

6. The preparation method according to claim 1, characterized in that: In step 2, the dropping rate of the metal salt solution and the complexing agent is controlled at 2-6 mL / min, and the dropping rate of the precipitant is adjusted in real time according to the pH value of the reaction environment. The preferred dropping rate is 3-5 mL / min.

7. The preparation method according to claim 1, characterized in that: The entire coprecipitation reaction is divided into three stages. In the first stage, the pH value is controlled between 10-11.8, and the reaction lasts for 1-4 hours; in the second stage, the pH value is controlled between 11.8-13, and the reaction lasts for 4-10 hours; in the third stage, the pH value is controlled between 10.5-11.8, and the reaction lasts for 2-6 hours. Preferably, the pH value is controlled between 10.5-11.5 in the first stage, and the reaction lasts for 2-4 hours; the pH value is controlled between 11.5-12.5 in the second stage, and the reaction lasts for 5-12 hours; and the pH value is controlled between 11.0-11.8 in the third stage, and the reaction lasts for 3-6 hours. The total reaction time is 12-22 hours.

8. The preparation method according to claim 1, characterized in that: Step 3: The temperature of the aging process is 60-120°C, and the standing time is 6-30 hours. Preferably, the temperature of the aging process is 70-100°C, and the standing time is 12-24 hours.

9. The preparation method according to claim 1, characterized in that: In step 4, the lithium source is one or more of lithium hydroxide (LiOH), lithium carbonate (Li2CO3), lithium nitrate (LiNO3) and hydrates thereof, among which LiOH·H2O and Li2CO3 are preferred.

10. The preparation method according to claim 1, characterized in that: The entire sintering process needs to be divided into three stages. In the first stage, the temperature is raised to 400-650℃ and kept for 3-8 hours, and the heating rate is controlled at 3-5℃ / min; in the second stage, the temperature is raised to 700-950℃ and kept for 10-20 hours, and the heating rate is controlled at 1-2℃ / min; in the third stage, the temperature is lowered to 400-650℃, the cooling rate is controlled at 1-2℃ / min, and finally naturally cooled to room temperature. Among them, as a preferred method, the first stage is heated to 400-600℃ and kept for 3-6 hours, and the heating rate is controlled at 3-5℃ / min; in the second stage, the temperature is raised to 700-900℃ and kept for 12-18 hours, and the heating rate is controlled at 1-2℃ / min; in the third stage, the temperature is lowered to 400-600℃, and the cooling rate is controlled at 1-2℃ / min.

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