Hydrophobic composite lithium nickel cobalt manganese oxide material and preparation method thereof
By multi-layer coating and hydrophobic layer treatment on the surface of high-nickel ternary materials, the thermal stability and water absorption problems of nickel-cobalt-manganese lithium oxide batteries are solved, achieving a balance between high capacity and safety, and simplifying the battery manufacturing process.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- YICHUN GUOXUAN BATTERY CO LTD
- Filing Date
- 2023-03-29
- Publication Date
- 2026-07-31
AI Technical Summary
High-nickel-content lithium nickel cobalt manganese oxide batteries suffer from poor thermal stability and are prone to moisture absorption and deliquescence, leading to localized overcharging and thermal runaway of the battery electrodes and material failure during the manufacturing process.
A high-nickel ternary material precursor, NCM811, was prepared by liquid-phase sedimentation. Then, a first coating layer of Ni0.8Co0.1Mn0.05Al0.05, a second coating layer of Ni0.6Co0.2Mn0.2, and a hydrophobic polyurethane layer were sequentially coated on its surface by impregnation coating to form a hydrophobic composite lithium nickel cobalt manganese oxide material.
It improves the thermal stability of the material, prevents thermal runaway, and blocks water absorption through a hydrophobic layer, ensuring stable material performance and simplifying the battery manufacturing process.
Smart Images
Figure CN116417592B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of ternary materials technology, and in particular to a hydrophobic composite lithium nickel cobalt manganese oxide material and its preparation method. Background Technology
[0002] Ternary cathode materials and lithium iron phosphate (LFP) materials are currently the two major battery material systems operating in parallel in the lithium battery market. Compared to LFP and lithium manganese oxide cathode materials, ternary materials have higher energy density and longer driving range. Nickel-cobalt-manganese (NiCoMn) ternary materials combine the advantages of lithium cobalt oxide, lithium nickel oxide, and lithium manganese oxide cathode materials, exhibiting a significant synergistic effect, making them the mainstream ternary cathode material. Currently, NiCoMn ternary materials can be divided into medium-nickel (mainly 5-series materials such as NCM523), medium-high nickel (mainly 6-series materials such as NCM613 and NCM622), and high-nickel (mainly 8-series materials such as NCM811). Energy density increases with increasing nickel content. High-nickel ternary materials, due to their continuously increasing nickel content, have a significant advantage in specific energy and are therefore attracting considerable attention. They have broad application prospects in electric vehicles, buses, distributed networks, and other fields requiring long driving range and high specific energy.
[0003] However, with the continuous increase in nickel content, the stability of the coordination units formed by metal oxides in ternary lithium batteries becomes increasingly poor, especially in NCM811 batteries, which suffer from severe thermal runaway problems caused by localized overcharging of the battery electrodes. Summer, with its higher temperatures, becomes a peak period for thermal runaway in NCM811 batteries, leading to frequent fires in electric vehicles, buses, and energy storage stations. Furthermore, with the continuous increase in nickel content, the alkalinity of ternary lithium materials increases, resulting in increasingly strong hygroscopicity. After absorbing water, the material will gradually hydrolyze and form lithium compounds such as lithium carbonate, causing material failure. Simultaneously, during battery manufacturing, the high alkalinity of NCM811 material makes the slurry highly susceptible to water absorption and spoilage, and the battery electrodes are prone to water rebound, posing numerous obstacles to battery manufacturing. Summary of the Invention
[0004] Based on the technical problems existing in the background technology, the present invention proposes a hydrophobic composite lithium nickel cobalt manganese oxide material and its preparation method, which improves the defects of poor thermal stability and easy water absorption and deliquescence of existing high nickel content lithium nickel cobalt manganese oxide batteries.
[0005] This invention proposes a hydrophobic composite lithium nickel cobalt manganese oxide material, comprising a Ni composition. 0.8 Co 0.1 Mn 0.1 The core, and the Ni formed by sequentially coating the core. 0.8 Co 0.1 Mn 0.05 Al0.05 The first coating layer is composed of Ni 0.6 Co 0.2 Mn 0.2 The second coating layer and the hydrophobic coating layer.
[0006] Preferably, the first coating layer, the second coating layer, and the hydrophobic coating layer account for 10-18%, 3-8%, and 0.1-5% of the mass of the hydrophobic composite lithium nickel cobalt manganese oxide material, respectively; preferably, the hydrophobic coating layer is composed of hydrophobic polyurethane.
[0007] This invention also proposes a method for preparing the above-mentioned hydrophobic composite lithium nickel cobalt manganese oxide material, comprising the following steps:
[0008] S1. Arrange the nickel source, cobalt source, and manganese source according to n Ni :n Co :n Mn Ni was dissolved in deionized water at a stoichiometric ratio of 8:1:1, the pH was adjusted to 9-11, the reaction was stirred, nucleation and precipitation occurred, the samples were separated, washed, and dried to obtain Ni. 0.8 Co 0.1 Mn 0.1 Precursor;
[0009] S2, The nickel source, cobalt source, manganese source, and aluminum source are arranged according to n Ni :n Co :n Mn :n Al Ni was dissolved in deionized water at a stoichiometric ratio of 8:1:0.5:0.5 to prepare a solution, and then Ni was added under stirring. 0.8 Co 0.1 Mn 0.1 The precursor is immersed in it, stirred, and settled to obtain a one-time coated composite precursor.
[0010] S3. Dissolve the nickel source, cobalt source and manganese source in deionized water according to the stoichiometric ratio of nNi:nCo:nMn = 6:2:2 to prepare a solution. Then immerse the primary coated composite precursor in the solution, stir, and allow it to settle to obtain the secondary coated composite precursor.
[0011] S4. Mix the secondary coated composite precursor and the lithium source, sinter, and pulverize to obtain the composite lithium nickel cobalt manganese oxide material.
[0012] S5. Dissolve the hydrophobic material in an organic solvent to obtain a hydrophobic solution; mix the composite lithium nickel cobalt manganese oxide material and the hydrophobic solution, ball mill, and dry to obtain the hydrophobic composite lithium nickel cobalt manganese oxide material.
[0013] Preferably, the nickel source is one or more of nickel oxalate, nickel nitrate, nickel carbonate, nickel sulfate, and nickel chloride;
[0014] The manganese source is one or more of manganese nitrate, manganese carbonate, manganese hydroxide, and manganese chloride;
[0015] The cobalt source is one or more of cobalt nitrate, cobalt hydroxide, cobalt chloride, and cobalt sulfate;
[0016] The lithium source is one or more of lithium carbonate, lithium hydroxide, lithium acetate, lithium nitrate, and lithium oxalate.
[0017] Preferably, in S1, ammonia is used to adjust the pH of the system to 9-11; preferably, the ammonia concentration is 25-28 wt%.
[0018] Preferably, in S2 and S3, the mixture is stirred at 23–28°C and a speed of 8–15 r / min for 15–28 min before settling.
[0019] Preferably, in S4, the secondary coating composite precursor and the lithium source are mixed by dry powder ball milling or spray drying.
[0020] Preferably, the mass ratio of lithium source to secondary coated composite precursor is 1:2.4 to 2.7.
[0021] Preferably, the sintering process is as follows: first, pre-fire at 380-620℃ for 1-6.5 hours, then raise the temperature to 723-1050℃ and sinter in an oxygen atmosphere for 9-15 hours.
[0022] Preferably, in step S5, after drying at 60–70°C for 30–60 min, the material is then sintered at 105–120°C for 0.5–3 h under a protective atmosphere.
[0023] Preferably, the hydrophobic material is hydrophobic polyurethane, and the hydrophobic solution is prepared by dissolving the hydrophobic polyurethane in ethanol.
[0024] This invention also proposes the application of the above-mentioned hydrophobic composite lithium nickel cobalt manganese oxide material as a ternary cathode material in lithium-ion batteries.
[0025] Beneficial Effects: This invention proposes a hydrophobic composite lithium nickel cobalt manganese oxide material. An NCM811 high-nickel ternary material precursor is prepared using a liquid-phase sedimentation method. Then, a ternary nickel-cobalt-aluminum material and a thermally stable NCM622 lithium nickel cobalt manganese oxide material are sequentially coated onto the surface of the NCM811 high-nickel ternary material through impregnation and sintering. The inner high-nickel material ensures high capacity, while the nickel content decreases layer by layer from the inside out, increasing the material's structural stability. This ensures high capacity and high performance of the high-nickel ternary material while simultaneously improving material safety and addressing the thermal runaway problem. Furthermore, coating the surface of the composite ternary material with a hydrophobic layer blocks water absorption, ensuring material performance and simplifying process control during battery fabrication. Attached Figure Description
[0026] Figure 1 This is a schematic diagram of the structure of the hydrophobic composite lithium nickel cobalt manganese oxide material proposed in this invention;
[0027] Figure 2 Ni prepared in Example 1 of this invention 0.8 Co 0.1 Mn 0.1 SEM image of the precursor, scale bar 50 μm;
[0028] Figure 3 The image shows a SEM image of the hydrophobic composite lithium nickel cobalt manganese oxide material prepared in Example 1 of this invention, with a scale bar of 50 μm. Detailed Implementation
[0029] Figure 1 This is a schematic diagram of the structure of the hydrophobic composite lithium nickel cobalt manganese oxide material proposed in this invention, as shown below. Figure 1 As shown, the hydrophobic composite lithium nickel cobalt manganese oxide material comprises Ni 0.8 Co 0.1 Mn 0.1 The core, and the Ni formed by sequentially coating the core. 0.8 Co 0.1 Mn 0.05 Al 0.05 The first coating layer is composed of Ni 0.6 Co 0.2 Mn 0.2 The second coating layer and the hydrophobic coating layer.
[0030] The technical solution of the present invention will now be described in detail through specific embodiments.
[0031] Example 1
[0032] The preparation steps of a hydrophobic composite lithium nickel cobalt manganese oxide material are as follows:
[0033] S1. Weigh 619.04 kg of nickel sulfate and slowly add it to 1500 kg of deionized water while stirring, at a water temperature of 40-45℃, to form a saturated solution; weigh 75.5 kg of manganese sulfate and slowly add it to 200 kg of deionized water while stirring, at a water temperature of 40-45℃, to form a saturated solution; weigh 140.56 kg of cobalt sulfate and slowly add it to 350 kg of deionized water while stirring, at a water temperature of 40-45℃, to form a saturated solution.
[0034] The saturated solutions of these three substances were then continuously mixed in a stoichiometric ratio of Ni:Co:Mn = 8:1:1 in a sedimentation tank at a stirring speed of 30 r / min. Ammonia was gradually and slowly added to the sedimentation tank to adjust the pH to 10.5. The mixture was stirred as ammonia was added. 0.8 Co 0.1 Mn 0.1 The precursor gradually settles. The settling process continues, forming a primary precursor.
[0035] S2. In storage tank No. 1, 310 kg of nickel sulfate, 27.7 kg of manganese sulfate, 70.28 kg of cobalt sulfate, and 20.5 kg of sodium aluminate were added to 1000 kg of deionized water under stirring to prepare a mixed solution with a stoichiometric ratio of Ni:Co:Mn:Al = 8:1:0.5:0.5. The Ni obtained in S1... 0.8 Co 0.1 Mn 0.1 The precursor was slowly added to storage tank No. 1 under stirring. The mixture was stirred slowly at a speed of 15 r / min for 25 min, followed by a coating treatment. After settling, a Ni-coated surface was obtained. 0.8 Co 0.1 Mn 0.05 Al 0.05 Ternary Ni in the transition layer 0.8 Co 0.1 Mn 0.1 Precursor.
[0036] S3. In storage tank No. 2, 92.86 kg of nickel sulfate, 30.2 kg of manganese sulfate, and 56.23 kg of cobalt sulfate were added to 450 kg of deionized water under stirring to prepare a mixed solution with a stoichiometric ratio of Ni:Co:Mn = 6:2:2. The surface coated with Ni obtained in S2 was then... 0.8 Co 0.1 Mn 0.05 Al 0.05 Ternary Ni in the transition layer 0.8 Co 0.1 Mn 0.1 The precursor was slowly added to storage tank No. 2 under stirring, and stirred at 15 rpm for 25 minutes for a second coating treatment. After sedimentation, Ni-coated products were obtained. 0.6 Co 0.2 Mn 0.2 Ternary Ni in the transition layer 0.8 Co 0.1 Mn 0.1 The precursor is dehydrated and dried to obtain the composite lithium nickel cobalt manganese oxide material precursor in this scheme, which is then used for later use.
[0037] S4. Weigh 205 kg of the dried composite nickel-cobalt-manganese lithium oxide precursor and 80.3 kg of micronized lithium carbonate, add an appropriate amount of deionized water, mix and ball-mill to form a uniform slurry. Spray dry at 240℃ to form micron-sized particles. After thoroughly drying the spray-dried particles, add them to a sintering dish. Pre-calcine at 480℃ for 4.5 hours to ensure sufficient wetting of the molten lithium carbonate with the precursor material. Then raise the temperature to 1050℃ and sinter under oxygen blowing for 15 hours. After sintering, cool to room temperature with the furnace, grind and air-jet pulverize, then coat to a particle size of 5-10 μm.
[0038] S5. Weigh 5 kg of polyurethane and add it to 17 kg of anhydrous ethanol to prepare an ethanol solution of polyurethane. Weigh 100 kg of the above-mentioned pulverized ternary material and mix it with the above-mentioned polyurethane ethanol solution. Ball mill for 3 hours, dry at 65°C for 40 min, and then sinter at 115°C for 1.5 hours under a protective atmosphere. Pulverize to obtain the hydrophobic composite lithium nickel cobalt manganese oxide ternary material described in this scheme.
[0039] For the Ni obtained 0.8 Co 0.1 Mn 0.1 The precursor and the hydrophobic composite lithium nickel cobalt manganese ternary material were characterized, and the results are shown in the figure. Figure 2 and Figure 3 .from Figure 2 As can be seen, the NCM811 ternary material precursor with a layered structure has a complete morphology and uniform distribution. Figure 3 The SEM image of the prepared hydrophobic composite lithium nickel cobalt manganese oxide shows that the precursor did not undergo a crystal transformation during the synthesis process.
[0040] Example 2
[0041] The preparation steps of a hydrophobic composite lithium nickel cobalt manganese oxide material are as follows:
[0042] S1. Weigh 309 kg of nickel sulfate, 38 kg of manganese sulfate, and 70.3 kg of cobalt sulfate, and prepare saturated solutions in separate stirred tanks under slow stirring at a temperature of 40°C. Then, continuously mix these saturated solutions according to a stoichiometric ratio of Ni:Co:Mn = 8:1:1 in a sedimentation tank at a stirring speed of 30 r / min. Gradually and slowly add ammonia to the sedimentation tank to adjust the pH to 11. While stirring, Ni... 0.8 Co 0.1 Mn 0.1 The precursor gradually settles. The settling process continues, forming a primary precursor.
[0043] S2. In storage tank No. 1, 620 kg of nickel sulfate, 55.4 kg of manganese sulfate, 140.56 kg of cobalt sulfate, and 41 kg of sodium aluminate were mixed under stirring to prepare a saturated mixed solution with a stoichiometric ratio of Ni:Co:Mn:Al = 8:1:0.5:0.5. The solution temperature was 40℃. The Ni obtained in S1... 0.8 Co 0.1 Mn 0.1 The precursor was slowly added to storage tank No. 1 under stirring, and stirred slowly at 15 r / min for 25 min to perform a coating treatment. After sedimentation, a Ni-coated surface was obtained. 0.8 Co 0.1 Mn 0.05 Al 0.05 Ternary Ni in the transition layer 0.8 Co 0.1 Mn 0.1 Precursor.
[0044] S3. In storage tank No. 2, a saturated mixed solution of Ni:Co:Mn:Al = 6:2:2 was prepared by mixing 92.86 kg of nickel sulfate, 30.2 kg of manganese sulfate, and 56.23 kg of cobalt sulfate under stirring. The solution temperature was 40℃. The surface of the solution prepared in S2 was coated with Ni. 0.8 Co 0.1 Mn 0.05 Al 0.05 Ternary Ni in the transition layer 0.8 Co 0.1 Mn 0.1 The precursor was slowly added to storage tank No. 2 under stirring, and stirred slowly at 15 rpm for 25 minutes. A second coating treatment was then performed, followed by sedimentation to obtain Ni-coated material. 0.6 Co 0.2 Mn 0.2 Ternary Ni in the transition layer 0.8 Co 0.1 Mn 0.1 The precursor is dehydrated and dried to obtain the composite lithium nickel cobalt manganese oxide material precursor in this scheme, which is then used for later use.
[0045] S4. Weigh 102.5 kg of the dried tertiary precursor and 40.2 kg of micronized lithium carbonate, add an appropriate amount of deionized water, mix and ball mill to form a uniform slurry. Spray dry at 285℃ to form micron-sized particles. After thoroughly drying the spray-dried particles, add them to a sintering dish. Pre-calcine at 620℃ for 5.5 hours to ensure sufficient wetting of the molten lithium carbonate with the precursor material. Then raise the temperature to 950℃ and sinter under oxygen blowing for 16 hours. After sintering, cool to room temperature in the furnace, grind and air-jet mill, then coat to a particle size of 5-10 μm.
[0046] S5. Weigh 5 kg of polyurethane and add it to 17 kg of anhydrous ethanol to prepare an ethanol solution of polyurethane. Weigh 100 kg of the pulverized ternary material and mix it with the ethanol solution. Ball mill the mixture for 3 hours, dry it at 60°C for 60 min, and then sinter it at 110°C for 2 hours under a protective atmosphere. Pulverize the sintered material to obtain the hydrophobic composite lithium nickel cobalt manganese oxide ternary material described in this scheme.
[0047] Example 3
[0048] The preparation steps of a hydrophobic composite lithium nickel cobalt manganese oxide material are as follows:
[0049] S1. Weigh 619.04 kg of nickel sulfate, 75.5 kg of manganese sulfate, and 140.56 kg of cobalt sulfate, and prepare saturated solutions in separate stirred tanks at 45°C. Then, continuously mix these saturated solutions in a stoichiometric ratio of Ni:Co:Mn = 8:1:1 in a sedimentation tank at a stirring speed of 25 r / min. Gradually and slowly add ammonia to the sedimentation tank to adjust the pH to 10. While stirring, Ni... 0.8 Co 0.1 Mn 0.1 The precursor gradually settles. The settling process continues, forming a primary precursor.
[0050] S2. In storage tank No. 1, 310 kg of nickel sulfate, 27.7 kg of manganese sulfate, 70.28 kg of cobalt sulfate, and 20.5 kg of sodium aluminate were mixed under stirring to prepare a saturated mixed solution with a stoichiometric ratio of Ni:Co:Mn:Al = 8:1:0.5:0.5. The solution temperature was 45℃. The Ni obtained in S1... 0.8 Co 0.1 Mn 0.1 The precursor was slowly added to storage tank No. 1 under stirring, and stirred slowly at 10 r / min for 25 min to perform a coating treatment, forming a surface coated with Ni. 0.8 Co 0.1 Mn 0.05 Al 0.05 Ternary Ni in the transition layer 0.8 Co 0.1 Mn 0.1 Precursor.
[0051] S3. In storage tank No. 2, 92.86 kg of nickel sulfate, 30.2 kg of manganese sulfate, and 56.23 kg of cobalt sulfate were mixed under stirring to prepare a saturated mixed solution with a stoichiometric ratio of Ni:Co:Mn = 6:2:2. The solution temperature was 45℃. The surface of the solution prepared in S2 was coated with Ni. 0.8 Co 0.1 Mn 0.05 Al 0.05 Ternary Ni in the transition layer 0.8 Co 0.1 Mn 0.1 The precursor was slowly added to storage tank No. 2 under stirring, and stirred at 10 rpm for 25 minutes to perform a secondary coating treatment, forming a Ni-coated product. 0.6 Co 0.2 Mn 0.2 Ternary Ni in the transition layer 0.8 Co 0.1 Mn 0.1 The precursor is dehydrated and dried to obtain the composite lithium nickel cobalt manganese oxide material precursor in this scheme, which is then used for later use.
[0052] S4. Weigh 205 kg of the dried composite nickel-cobalt-manganese lithium oxide precursor and 80.3 kg of micronized lithium carbonate, add an appropriate amount of deionized water, mix and ball-mill to form a uniform slurry. Spray dry at 240℃ to form micron-sized particles. After thoroughly drying the spray-dried particles, add them to a sintering dish. Pre-calcine at 450℃ for 5 hours to ensure sufficient wetting of the molten lithium carbonate with the precursor material. Then raise the temperature to 850℃ and sinter under oxygen blowing for 15 hours. After sintering, cool to room temperature in the furnace, grind and air-jet pulverize, then coat to a particle size of 5-10 μm.
[0053] S5. Weigh 3 kg of polyurethane and add it to 11 kg of anhydrous ethanol to prepare an ethanol solution of polyurethane. Weigh 100 kg of the pulverized ternary material and mix it with the polyurethane ethanol solution. Ball mill for 3 hours, dry at 65°C for 40 min, and then sinter at 120°C for 0.5 hours under a protective atmosphere. Pulverize the sintered material to obtain the hydrophobic composite lithium nickel cobalt manganese oxide ternary material described in this scheme.
[0054] Example 4
[0055] The preparation steps of a hydrophobic composite lithium nickel cobalt manganese oxide material are as follows:
[0056] S1. Weigh 619.04 kg of nickel sulfate, 75.5 kg of manganese sulfate, and 140.56 kg of cobalt sulfate, and prepare saturated solutions in separate stirred tanks at 45°C. Then, continuously mix these saturated solutions in a stoichiometric ratio of Ni:Co:Mn = 8:1:1 in a sedimentation tank at a stirring speed of 35 r / min. Gradually and slowly add ammonia to the sedimentation tank to adjust the pH to 10.5. While stirring, Ni... 0.8 Co 0.1 Mn 0.1 The precursor gradually settles. The settling process continues, forming a primary precursor.
[0057] S2. In storage tank No. 1, a saturated mixed solution with a stoichiometric ratio of Ni:Co:Mn:Al = 8:1:0.5:0.5 was prepared by stirring 310 kg of nickel sulfate, 27.7 kg of manganese sulfate, 70.28 kg of cobalt sulfate, and 20.5 kg of sodium aluminate. The solution temperature was 45℃. The Ni obtained in S1... 0.8 Co 0.1 Mn 0.1 The precursor was slowly added to storage tank No. 1 under stirring, and stirred slowly at 15 r / min for 25 min to perform a coating treatment, forming a surface coated with Ni. 0.8 Co 0.1 Mn 0.05 Al 0.05 Ternary Ni in the transition layer 0.8 Co 0.1 Mn 0.1 Precursor.
[0058] S3. In storage tank No. 2, a saturated mixed solution of Ni:Co:Mn:Al = 6:2:2 was prepared by stirring 92.86 kg of nickel sulfate, 30.2 kg of manganese sulfate, and 56.23 kg of cobalt sulfate. The solution temperature was 45℃. The surface of the solution prepared in S2 was coated with Ni. 0.8 Co 0.1 Mn 0.05 Al 0.05 Ternary Ni in the transition layer 0.8 Co 0.1 Mn 0.1 The precursor was slowly added to storage tank No. 2 under stirring, and stirred at 15 rpm for 25 minutes to perform a secondary coating treatment, forming a Ni-coated product. 0.6 Co 0.2 Mn 0.2 Ternary Ni in the transition layer 0.8 Co 0.1 Mn 0.1The precursor is dehydrated and dried to obtain the composite lithium nickel cobalt manganese oxide material precursor in this scheme, which is then used for later use.
[0059] S4. Weigh 205 kg of the dried composite nickel-cobalt-manganese lithium oxide precursor and 80.3 kg of micronized lithium carbonate, add an appropriate amount of deionized water, mix and ball-mill to form a uniform slurry. Spray dry at 240℃ to form micron-sized particles. After thoroughly drying the spray-dried particles, add them to a sintering dish. Pre-calcine at 560℃ for 5 hours to ensure sufficient wetting of the molten lithium carbonate with the precursor material. Then raise the temperature to 950℃ and sinter under oxygen blowing for 12 hours. After sintering, cool to room temperature in the furnace, grind and air-jet pulverize, then coat to a particle size of 5-10 μm.
[0060] S5. Weigh 1 kg of polyurethane and add it to 4 kg of anhydrous ethanol to prepare an ethanol solution of polyurethane. Weigh 100 kg of the pulverized ternary material and mix it with the polyurethane ethanol solution. Ball mill the mixture for 3 hours, dry it at 70°C for 30 minutes, and then sinter it at 105°C for 3 hours under a protective atmosphere. Pulverize the sintered material to obtain the hydrophobic composite lithium nickel cobalt manganese oxide ternary material described in this scheme.
[0061] Comparative Example 1
[0062] Compared to Example 1, the difference is that steps S2 and S5 are not included. Only in Ni 0.8 Co 0.1 Mn 0.1 Coated with a layer of Ni 0.6 Co 0.2 Mn 0.2 layer.
[0063] Comparative Example 2
[0064] Compared to Example 1, the difference is that steps S2 and S3 are not included. Only in Ni 0.8 Co 0.1 Mn 0.1 It is coated with a layer of polyurethane hydrophobic layer.
[0065] The performance of the hydrophobic composite lithium nickel cobalt manganese oxide materials prepared in Examples 1-4 and Comparative Examples 1-2 of this invention was tested.
[0066] Testing was conducted according to the TS16949 standard for automotive batteries, requiring the battery to be fully charged before the following tests were performed:
[0067] (1) Destructive test---needle puncture does not cause fire, explosion or smoke;
[0068] (2) Abuse test - short circuit test - needle puncture does not cause fire or explosion;
[0069] Water absorption test: The battery electrode is exposed to a -28°C dew point environment for 4 hours, and the thickness rebound of the electrode is tested to determine the electrode's adsorption of moisture in the air, thereby testing the water absorption performance of the material.
[0070] Rate discharge detection: Observe whether thermal runaway occurs.
[0071] The test results are shown in Table 1.
[0072] Table 1 Test Results
[0073]
[0074] As shown in Table 1, conventional NCM811 ternary materials suffer from severe thermal runaway, which is difficult to resolve. This invention employs multi-layer coating, effectively eliminating the thermal runaway problem of 811 while retaining its high capacity characteristics. Under high-rate discharge conditions, conventional 811 materials are more prone to thermal runaway under high-current discharge, while the material of this invention did not exhibit thermal runaway.
[0075] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.
Claims
1. A hydrophobic composite lithium nickel cobalt manganese oxide material, characterized in that, a core comprising Ni 0.8 Co 0.1 Mn 0.1 , and a first coating layer comprising Ni 0.8 Co 0.1 Mn 0.05 Al 0.05 , a second coating layer comprising Ni 0.6 Co 0.2 Mn 0.2 , and a hydrophobic coating layer; The hydrophobic coating layer is composed of hydrophobic polyurethane.
2. The hydrophobic composite lithium nickel cobalt manganese oxide material according to claim 1, characterized in that, The first coating layer, the second coating layer, and the hydrophobic coating layer account for 10-18%, 3-8%, and 0.1-5% of the mass of the hydrophobic composite lithium nickel cobalt manganese oxide material, respectively.
3. The method for preparing the hydrophobic composite lithium nickel cobalt manganese oxide material according to claim 1 or 2, characterized in that, Includes the following steps: S1, dissolve the nickel source, cobalt source and manganese source in deionized water according to the stoichiometric ratio of n Ni : n Co : n Mn =8:1:1, adjust the pH to 9-11, stir the reaction, nucleate and settle, separate, wash, dry, and obtain Ni 0.8 Co 0.1 Mn 0.1 precursor; S2, The nickel source, cobalt source, manganese source, and aluminum source are arranged according to n Ni :n Co :n Mn :n Al Ni was dissolved in deionized water at a stoichiometric ratio of 8:1:0.5:0.5 to prepare a solution, and then Ni was added under stirring. 0.8 Co 0.1 Mn 0.1 The precursor is immersed in it, stirred, and settled to obtain a one-time coated composite precursor. S3, a nickel source, a cobalt source and a manganese source are dissolved in deionized water according to the stoichiometric ratio of n Ni : n Co : n Mn = 6:2:2 to prepare a solution, and then the secondary coated composite precursor is obtained by immersing the primary coated composite precursor in the solution, stirring, and settling. S4. Mix the secondary coated composite precursor and the lithium source, sinter, and pulverize to obtain the composite lithium nickel cobalt manganese oxide material. S5. Dissolve the hydrophobic material in an organic solvent to obtain a hydrophobic solution; mix the composite lithium nickel cobalt manganese oxide material and the hydrophobic solution, ball mill, and dry to obtain the hydrophobic composite lithium nickel cobalt manganese oxide material.
4. The preparation method of the hydrophobic composite lithium nickel cobalt manganese oxide material according to claim 3, characterized in that, The nickel source is one or more of nickel oxalate, nickel nitrate, nickel carbonate, nickel sulfate, and nickel chloride; The manganese source is one or more of manganese nitrate, manganese carbonate, manganese hydroxide, and manganese chloride; The cobalt source is one or more of cobalt nitrate, cobalt hydroxide, cobalt chloride, and cobalt sulfate; The lithium source is one or more of lithium carbonate, lithium hydroxide, lithium acetate, lithium nitrate, and lithium oxalate.
5. The method for preparing the hydrophobic composite lithium nickel cobalt manganese oxide material according to claim 3 or 4, characterized in that, In S1, the pH of the system is adjusted to 9-11 using ammonia water; the concentration of the ammonia water is 25-28 wt%.
6. The preparation method of the hydrophobic composite lithium nickel cobalt manganese oxide material according to claim 3, characterized in that, In both S2 and S3, the mixture was stirred at 23-28℃ and a speed of 8-15 r / min for 15-28 minutes before settling.
7. The preparation method of the hydrophobic composite lithium nickel cobalt manganese oxide material according to claim 3, characterized in that, In S4, the secondary coating composite precursor and lithium source are mixed by dry powder ball milling or spray drying. The mass ratio of the lithium source to the secondary coated composite precursor is 1:2.4~2.7; The sintering process is as follows: first, pre-fire at 380~620℃ for 1~6.5h, then raise the temperature to 723~1050℃ and sinter in an oxygen atmosphere for 9~15h.
8. The preparation method of the hydrophobic composite lithium nickel cobalt manganese oxide material according to claim 3, characterized in that, In S5, after drying at 60~70℃ for 30~60 min, it is then sintered at 105~120℃ for 0.5~3 h under a protective atmosphere.
9. The preparation method of the hydrophobic composite lithium nickel cobalt manganese oxide material according to claim 3, characterized in that, The hydrophobic material is hydrophobic polyurethane, and the hydrophobic solution is prepared by dissolving the hydrophobic polyurethane in ethanol.
10. The application of the hydrophobic composite lithium nickel cobalt manganese oxide material prepared by the method of claim 1 or 2 or any one of claims 3-9 as a ternary cathode material in lithium-ion batteries.