Polycrystalline high-nickel ternary positive electrode material and preparation method and application thereof
By introducing pores and conductive agents into polycrystalline high-nickel ternary cathode materials, the problem of cracking caused by volume changes during cycling was solved, thereby improving the cycling stability and electrochemical performance of the materials.
Patent Information
- Application Number
- CN202511743861.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-25
- Publication Date
- 2026-02-17
AI Technical Summary
High-nickel ternary cathode materials develop cracks during cycling due to volume expansion and contraction, leading to premature battery failure.
Polycrystalline high-nickel ternary cathode materials are prepared, with pores on the surface and inside of the material, and coated with conductive agents such as carbon nanotubes, flake graphite, conductive fibers or amorphous carbon. The material structure is optimized by controlling the porosity, pore size and lithium-nickel mixing ratio.
The pores provide space for material expansion, reducing breakage, while the conductive agent improves current conduction efficiency and enhances cycle performance and electrochemical performance.
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Figure CN121546052A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of battery materials, in particular to a polycrystalline high-nickel ternary positive electrode material and a preparation method and application thereof. BACKGROUND
[0002] High-nickel ternary materials (NCM811 and NCM90, etc.) are positive electrode materials with high energy density in the lithium nickel cobalt manganese oxide system and are widely used in new energy vehicle power batteries. In recent years, with the progress of technology and the growth of market demand, high-nickel ternary materials have made significant progress in performance.
[0003] However, high-nickel ternary positive electrode materials will expand and shrink in volume during the cycle process, and the higher the nickel content, the more serious the phenomenon, resulting in a large number of cracks in the material in the later cycle stage and premature failure of the battery.
[0004] In view of this, the present application is proposed. SUMMARY
[0005] The present application aims to provide a polycrystalline high-nickel ternary positive electrode material and a preparation method and application thereof to solve or improve the above technical problems.
[0006] The present application can be achieved as follows: In a first aspect, the present application provides a polycrystalline high-nickel ternary positive electrode material, which comprises a polycrystalline high-nickel ternary positive electrode material body, the at least partial surface and at least partial internal region of the polycrystalline high-nickel ternary positive electrode material body have pores, and the surface of the at least polycrystalline high-nickel ternary positive electrode material body has a conductive agent.
[0007] In an optional embodiment, the polycrystalline high-nickel ternary positive electrode material further has at least one of the following characteristics: Characteristic 1: the general formula of the polycrystalline high-nickel ternary positive electrode material body is LiNi x Co y Mn z O2, wherein x>0.6, y>0, z>0, and x+y+z=1; Characteristic 2: the conductive agent comprises at least one of carbon nanotubes, flaky graphite, conductive fibers and amorphous carbon; Characteristic 3: the Dv 50 of the polycrystalline high-nickel ternary positive electrode material is 7-12 microns; Characteristic 4: the porosity of the polycrystalline high-nickel ternary positive electrode material is 1.5%-3.5%; Characteristic 5: the pore size corresponding to the pores in the internal region of the polycrystalline high-nickel ternary positive electrode material is 0.2-1.0 microns; Characteristic 6: the lithium-nickel mixing ratio of the polycrystalline high-nickel ternary positive electrode material is 1.89%-1.96%. Feature 7: The specific surface area of the polycrystalline high-nickel ternary cathode material is 0.95 m². 2 / g~1.05m 2 / g; Feature 8: Dn of polycrystalline high-nickel ternary cathode material 10 The thickness is 3.30μm~3.35μm; Feature 9: The carbon content of the polycrystalline high-nickel ternary cathode material is 1%~3%.
[0008] Secondly, the present invention provides a method for preparing a polycrystalline high-nickel ternary cathode material as described in the foregoing embodiments, comprising the following steps: mixing a nickel-cobalt-manganese hydroxide precursor doped with a pore-forming agent with a lithium-containing compound, followed by calcination to obtain a first intermediate material; cleaning the first intermediate material with a water washing solution, followed by solid-liquid separation and drying to obtain a second intermediate material; mixing the second intermediate material with a carbon source for forming a conductive agent, and sintering to obtain a polycrystalline high-nickel ternary cathode material.
[0009] In an optional embodiment, the preparation of a nickel cobalt manganese hydroxide precursor doped with a pore-forming agent includes: mixing a suspension of the nickel cobalt manganese hydroxide precursor with a pore-forming agent solution, and then carrying out an ion exchange reaction under conditions of a temperature of 40°C to 80°C, a pH of 10.0 to 11.0, and an ammonia concentration of 4 g / L to 8 g / L.
[0010] In an optional implementation, the ion exchange reaction time is 3h to 10h.
[0011] In an optional embodiment, the volume ratio of the suspension to the pore-forming agent solution is 1:1 to 1:4, wherein the concentration of the nickel cobalt manganese hydroxide precursor in the suspension is 100 g / L to 800 g / L, and the concentration of the pore-forming agent in the pore-forming agent solution is 0.01 g / L to 0.1 g / L.
[0012] In an optional embodiment, the concentration of the pore-forming agent in the pore-forming agent solution is 0.02 g / L to 0.05 g / L.
[0013] In an optional embodiment, the pore-forming agent includes at least one of a metal sulfate and a metal hydrochloride.
[0014] In an optional embodiment, the pore-forming agent includes at least one of potassium sulfate, sodium sulfate, lithium sulfate, aluminum sulfate, cobalt sulfate, manganese sulfate, nickel sulfate, zinc sulfate, copper sulfate, ferric sulfate, potassium chloride, sodium chloride, lithium chloride, aluminum chloride, cobalt chloride, manganese chloride, nickel chloride, zinc chloride, copper chloride, and ferric chloride.
[0015] In an optional embodiment, the preparation of the first intermediate material includes at least one of the following features: Feature 10: the lithium-containing compound includes at least one of lithium oxalate, lithium carbonate, lithium hydroxide monohydrate, lithium acetate, and lithium citrate; Feature 11: the ratio of the total moles of nickel, cobalt, and manganese in the surface-doped pore-forming agent-containing nickel-cobalt-manganese hydroxide precursor to the moles of lithium in the lithium-containing compound is 1:1 to 1:1.2; Feature 12: the calcination includes: first-stage calcination under conditions of 300°C to 750°C, second-stage calcination under conditions of 800°C to 1100°C, and third-stage calcination under conditions of 500°C to 750°C.
[0016] In optional embodiments, the holding time of the first-stage calcination is 3h to 10h, the holding time of the second-stage calcination is no more than 10h, and the holding time of the third-stage calcination is 10h to 15h.
[0017] In optional embodiments, the preparation of the second intermediate material includes at least one of the following features: Feature 13: the water washing solution is an aqueous metal salt solution, the concentration of the metal salt in the aqueous metal salt solution is 500g / 3L to 1500g / 3L, and the mass ratio of the metal salt in the aqueous metal salt solution to the first intermediate material is 1:2 to 1:10; Feature 14: the water washing solution is an aqueous metal salt solution, the anion of the metal salt in the aqueous metal salt solution is the same as the anion of the pore-forming agent in the pore-forming agent solution; preferably, the metal salt includes at least one of potassium sulfate, sodium sulfate, lithium sulfate, aluminum sulfate, cobalt sulfate, manganese sulfate, nickel sulfate, zinc sulfate, copper sulfate, and iron sulfate; Feature 15: the temperature of the water washing solution is 1.5°C to 20°C; Feature 16: the drying temperature is 100°C to 180°C, and the drying time is 2h to 20h.
[0018] In optional embodiments, the preparation of the polycrystalline high-nickel ternary positive electrode material includes at least one of the following features: Feature 17: the mass ratio of the second intermediate material to the conductive agent is 3:0.05 to 3:0.1; Feature 18: the glucose is attached to the second intermediate material in the form of a solution by spraying, and amorphous carbon is formed by sintering; Feature 19: the sintering temperature is 200°C to 500°C, and the sintering time is 3h to 15h.
[0019] In a third aspect, the present application provides a battery containing the polycrystalline high-nickel ternary positive electrode material of any one of the preceding embodiments.
[0020] In a fourth aspect, the present application provides an electric device including the battery of the preceding embodiments.
[0021] The beneficial effects of the present application include: The polycrystalline high-nickel ternary positive electrode material provided by the present application contains pores that can reserve space for material expansion during the cycle process, reduce material breakage, and enhance the cycle performance of the material. In addition, the conductive agent exists at least on the surface of the polycrystalline high-nickel ternary positive electrode material body, which is not only conducive to stabilizing the structure and optimizing the current conduction, but also can more efficiently transfer charges during the charging and discharging process, thereby improving the electrochemical performance. BRIEF DESCRIPTION OF DRAWINGS
[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be considered as limiting the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.
[0023] Figure 1 SEM image of the surface of the polycrystalline high-nickel ternary positive electrode material prepared in Example 1; Figure 2 SEM image of the cross section of the polycrystalline high-nickel ternary positive electrode material prepared in Example 1; Figure 3 XRD image of the polycrystalline high-nickel ternary positive electrode material prepared in Example 1; Figure 4 Cycle capacity retention rate result graph of the battery corresponding to the ternary positive electrode material provided in Examples 1-2 and Comparative Examples 4-6. DETAILED DESCRIPTION
[0024] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be described clearly and completely below. If the specific conditions are not specified in the embodiments, the conventional conditions or the conditions recommended by the manufacturer are used. If the reagents or instruments used are not specified by the manufacturer, they are all conventional products that can be purchased on the market.
[0025] The polycrystalline high-nickel ternary positive electrode material provided by the present application and the preparation method and application thereof will be described in detail below.
[0026] The present application provides a polycrystalline high-nickel ternary positive electrode material, which comprises a polycrystalline high-nickel ternary positive electrode material body, pores in at least part of the surface and at least part of the internal region of the polycrystalline high-nickel ternary positive electrode material body, and a conductive agent on at least the surface of the polycrystalline high-nickel ternary positive electrode material body.
[0027] The holes in the polycrystalline high-nickel ternary positive electrode material can reserve space for material expansion during the cycle process, reduce material crushing, and enhance the cycle performance of the material. In addition, the conductive agent exists at least on the surface of the polycrystalline high-nickel ternary positive electrode material body, which is not only conducive to stabilizing the structure and optimizing the current conduction, but also can more efficiently transfer charges during the charging and discharging process, thereby improving the electrochemical performance.
[0028] In some optional embodiments, the general formula of the polycrystalline high-nickel ternary positive electrode material body can be LiNi x Co y Mn z O2, wherein x≥0.6, y≥0, z≥0, and x+y+z=1.
[0029] In some optional embodiments, the conductive agent can exemplarily but non-limitingly include at least one of carbon nanotubes, flake graphite, conductive fibers, and amorphous carbon.
[0030] In some optional embodiments, the Dv 50 of the polycrystalline high-nickel ternary positive electrode material can be 7 μm~12 μm, such as 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, or 12 μm, etc., or other values within the range of 7 μm~12 μm, such as 10 μm~10.38 μm.
[0031] In some optional embodiments, the Dv n10 of the polycrystalline high-nickel ternary positive electrode material can be 3.30 μm~3.35 μm.
[0032] The above-mentioned “Dv 50 ” refers to the particle size value when the cumulative particle size distribution reaches 50%; and “Dn10” refers to the number distribution, which refers to the particle diameter at the top 10% position when the particles in the sample are arranged from small to large.
[0033] In some optional embodiments, the porosity of the polycrystalline high-nickel ternary positive electrode material can be 1.5%~3.5%, such as 1.5%, 2%, 2.5%, 3%, or 3.5%, etc., or other values within the range of 1.5%~3.5%, such as 1.63%~1.87%.
[0034] If the porosity is less than 1.5%, it is not conducive to alleviating the volume expansion of the material during the cycle process; and if the porosity is greater than 3.5%, it is not conducive to maintaining the structural stability of the material during the cycle process.
[0035] In some optional embodiments, the pore size corresponding to the holes in the internal region of the polycrystalline high-nickel ternary positive electrode material can be 0.2 μm~1.0 μm.
[0036] Controlling the pore size of the hole in the above range can avoid the material from being broken too early in the cycle process.
[0037] In some optional embodiments, the lithium-nickel mixing ratio of the polycrystal high-nickel ternary positive electrode material is 1.89%~1.96%, which is beneficial to the stability of the material in the cycle process.
[0038] In some optional embodiments, the specific surface area of the polycrystal high-nickel ternary positive electrode material is 0.95m 2 / g~1.05m 2 / g, which is beneficial to reducing the side reactions of the material in the cycle process.
[0039] In some optional embodiments, the carbon content of the polycrystal high-nickel ternary positive electrode material is 1%~3%, which is beneficial to enhancing the conductivity of the material.
[0040] Correspondingly, the application also provides a preparation method of the polycrystal high-nickel ternary positive electrode material, which comprises the following steps: mixing a nickel-cobalt-manganese hydroxide precursor doped with a pore-forming agent on the surface with a lithium-containing compound, and then calcining to obtain a first intermediate material; washing the first intermediate material with a water washing solution, and then performing solid-liquid separation, drying to obtain a second intermediate material; mixing the second intermediate material with a carbon source for forming a conductive agent, and sintering to obtain the polycrystal high-nickel ternary positive electrode material.
[0041] In some optional embodiments, the preparation of the nickel-cobalt-manganese hydroxide precursor doped with a pore-forming agent can comprise: mixing a suspension of the nickel-cobalt-manganese hydroxide precursor with a pore-forming agent solution, and then performing ion exchange reaction under the conditions that the temperature is 40℃~80℃, the pH value is 10.0~11.0, and the ammonia concentration is 4g / L~8g / L. In the above process, the ammonia concentration of the ion exchange reaction can be adjusted by supplementing ammonia water, and the pH value of the ion exchange reaction can be adjusted by supplementing alkali solution.
[0042] The general formula of the nickel-cobalt-manganese hydroxide precursor is Ni x Co y Mn z (OH)2, x≥0.6, y≥0, z≥0, and x+y+z=1. The nickel-cobalt-manganese hydroxide precursor can be directly purchased or prepared by referring to the existing technology in the art. The suspension of the nickel-cobalt-manganese hydroxide precursor can be obtained by dispersing the nickel-cobalt-manganese hydroxide precursor in water. Exemplarily, the concentration of the nickel-cobalt-manganese hydroxide precursor in the suspension can be 100g / L~800g / L.
[0043] The volume ratio of the above suspension to the pore-forming agent solution can be 1:1 to 1:4, such as 1:1, 1:2, 1:3, or 1:4, or the like, or other values within the range of 1:1 to 1:4. Among them, the concentration of the pore-forming agent in the pore-forming agent solution can be 0.01 g / L to 0.1 g / L, such as 0.01 g / L, 0.02 g / L, 0.05 g / L, or 0.1 g / L, or the like, or other values within the range of 0.01 g / L to 0.1 g / L. In some optional embodiments, the concentration of the pore-forming agent in the pore-forming agent solution can be 0.02 g / L to 0.05 g / L.
[0044] The amount of the pore-forming agent is directly related to the porosity of the final material. If the amount of the pore-forming agent is too small, the porosity of the polycrystalline high-nickel ternary positive electrode material will be too low. If the amount of the pore-forming agent is too large, the porosity of the polycrystalline high-nickel ternary positive electrode material will be too high.
[0045] In some optional embodiments, the pore-forming agent can include at least one of a metal sulfate and a metal hydrochloride. As an enumeration, the pore-forming agent can include at least one of potassium sulfate, sodium sulfate, lithium sulfate, aluminum sulfate, cobalt sulfate, manganese sulfate, nickel sulfate, zinc sulfate, copper sulfate, iron sulfate, potassium chloride, sodium chloride, lithium chloride, aluminum chloride, cobalt chloride, manganese chloride, nickel chloride, zinc chloride, copper chloride, and iron chloride, for example.
[0046] In some optional embodiments, the temperature of the ion exchange reaction can be 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, or 80°C, or the like, or other values within the range of 40°C to 80°C.
[0047] The pH value of the ion exchange reaction can be 10, 10.2, 10.5, 10.8, or 11, or the like, or other values within the range of 10.0 to 11.0.
[0048] The ammonia concentration of the ion exchange reaction can be 4 g / L, 5 g / L, 6 g / L, 7 g / L, or 8 g / L, or the like, or other values within the range of 4 g / L to 8 g / L.
[0049] The time of the ion exchange reaction can be 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, or 10 h, or the like, or other values within the range of 3 h to 10 h.
[0050] By allowing the suspension of the nickel-cobalt-manganese hydroxide precursor to react with the pore-forming agent solution under the above conditions, a nickel-cobalt-manganese hydroxide precursor doped with a pore-forming agent on the surface can be obtained.
[0051] In some optional embodiments, the lithium-containing compound can exemplarily include at least one of lithium oxalate, lithium carbonate, lithium hydroxide monohydrate, lithium acetate, and lithium citrate.
[0052] The ratio of the total moles of nickel, cobalt and manganese in the surface-doped pore-forming agent nickel-cobalt-manganese hydroxide precursor to the moles of lithium in the lithium-containing compound can be 1:1 to 1:1.2, such as 1:1, 1:1.1 or 1:1.2, or other values within the range of 1:1 to 1:1.2.
[0053] In some alternative embodiments, the calcination comprises: first performing a first-stage calcination under conditions of 300°C to 750°C (such as 300°C, 350°C, 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C or 750°C, etc.), then performing a second-stage calcination under conditions of 800°C to 1100°C (such as 800°C, 850°C, 900°C, 950°C, 1000°C, 1050°C or 1100°C, etc.), and then performing a third-stage calcination under conditions of 500°C to 750°C (such as 500°C, 550°C, 600°C, 650°C, 700°C or 750°C, etc.). The above process can be performed in an oxygen atmosphere.
[0054] The holding time of the first-stage calcination can be 3h to 10h (such as 3h, 4h, 5h, 6h, 7h, 8h, 9h or 10h, etc.), the holding time of the second-stage calcination is not more than 10h (such as 1h, 2h, 4h, 6h, 8h or 10h, etc.), and the holding time of the third-stage calcination is 10h to 15h (such as 10h, 11h, 12h, 13h, 14h or 15h, etc.).
[0055] The above calcination process is divided into three stages, wherein the first stage mainly serves to dehydrate the precursor and the lithium source, the second stage mainly serves to rapidly react the precursor with the lithium source, and the third stage mainly serves to enhance the crystallinity of the material.
[0056] The above calcination process can have a heating rate of 5°C / min to heat up to the target temperature in a short time, so as to promote the surface-doped pore-forming agent to further penetrate into the nickel-cobalt-manganese hydroxide precursor, and at the high temperature of the second stage, the pore-forming agent fuses with the material and inhibits the contact between primary particles, so as to form pores on the surface and inside the first intermediate material. In addition, through the above three-stage calcination, the size of the primary particles corresponding to the first intermediate material is within a suitable range, which is conducive to ensuring that the material has a better capacity.
[0057] In some alternative embodiments, the water washing solution used for water washing the first intermediate material is a metal salt aqueous solution. The concentration of the metal salt in the water washing solution can be 500g / 3L to 1500g / 3L, such as 500g / 3L, 1000g / 3L or 1500g / 3L, etc. The mass ratio of the metal salt in the water washing solution to the first intermediate material can be 1:2 to 1:10, such as 1:2, 1:5, 1:8 or 1:10, etc.
[0058] The anion of the metal salt in the above-mentioned aqueous solution is the same as the anion of the pore-forming agent in the pore-forming agent solution. For example, the metal salt in the aqueous solution may include at least one of potassium sulfate, sodium sulfate, lithium sulfate, aluminum sulfate, cobalt sulfate, manganese sulfate, nickel sulfate, zinc sulfate, copper sulfate, and ferric sulfate.
[0059] In some alternative embodiments, the temperature of the washing solution can be 1.5℃ to 20℃, such as 1.5℃, 5℃, 10℃, 15℃ or 20℃, or other values within the range of 1.5℃ to 20℃.
[0060] If the temperature of the above-mentioned washing solution is higher than 20°C, it can easily lead to excessive lithium extraction from the material.
[0061] After the washing solution is mixed with the first intermediate material, it is stirred for 10 min to 60 min, then centrifuged in a centrifuge at 45 Hz to 55 Hz for 0.5 h to 1.5 h, and then dried in a vacuum drying oven.
[0062] In some alternative embodiments, the drying temperature can be 100°C to 180°C, such as 100°C, 120°C, 150°C or 180°C, or other values within the range of 100°C to 180°C.
[0063] In some alternative implementations, the drying time can be 2h to 20h, such as 2h, 5h, 10h, 15h or 20h, or other values within the range of 2h to 20h.
[0064] This invention removes residual or excess pore-forming agent by washing the first intermediate material with a water washing solution, preventing the pore-forming agent from remaining inside the first intermediate material and affecting its capacity. However, if pure water is used for washing, the pore-forming agent will rapidly leave the material, thereby weakening the interparticle bonding force on the material surface and causing powdering. Therefore, this invention specifically adds a specific metal salt to the water to form a metal salt aqueous solution. The anions in this metal salt are the same as those in the pore-forming agent, and the cations in this metal salt can be deposited on the material surface. The anions, being the same as those in the pore-forming agent, slow down the dissolution rate of the pore-forming agent inside the material, controlling the water washing rate to maintain a relatively balanced state and preventing structural collapse; the cations can contact the residual alkali on the material surface and deposit there, providing a protective effect and reducing powdering. The reaction equation between the cations and the residual alkali includes: M n+ +nOH - =M(OH) n ↓; M n+ +0.5nCO3 2- =M(CO3) 0.5n↓; where "M" represents a cation.
[0065] In some alternative embodiments, the mass ratio of the second intermediate material to the conductive agent can be 3:0.05 to 3:0.1, such as 3:0.05, 3:0.075 or 3:0.1.
[0066] In some alternative embodiments, glucose is applied to the second intermediate material in solution form by spraying, for example, at least onto the surface of the material, and further possibly into the pores of the material, and then sintered to form amorphous carbon. For example, 50g to 250g of glucose can be dissolved in 100mL to 500mL of deionized water to obtain a glucose solution; the glucose solution is then uniformly sprayed onto the second intermediate material using a spraying device.
[0067] In some alternative embodiments, the sintering temperature can be 200℃~500℃, such as 200℃, 250℃, 300℃, 350℃, 400℃, 450℃ or 500℃, or other values within the range of 200℃~500℃.
[0068] The sintering time can be 3h to 15h, such as 3h, 5h, 8h, 10h, 12h or 15h, or other values within the range of 3h to 15h.
[0069] By attaching glucose, which is used to form amorphous carbon, to at least the surface of the material and then carbonizing it after high-temperature sintering, the conductivity of polycrystalline high-nickel ternary materials can be improved while stabilizing the structure, thereby improving the overall performance of the battery.
[0070] In addition, the present invention also provides a battery cell, wherein the positive electrode material of the battery cell includes the above-mentioned polycrystalline high-nickel ternary positive electrode material.
[0071] The above sintering process can be carried out in an oxygen-free atmosphere (such as a nitrogen atmosphere).
[0072] For example, the aforementioned battery cells can be used, but are not limited to, in electrical devices such as vehicles, ships, or aircraft.
[0073] The present invention also provides a battery comprising the above-described battery cells, which has superior cycle performance.
[0074] The present invention also provides an electrical device comprising the aforementioned battery cell and / or battery. As examples, the electrical device may include, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys may include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., while spacecraft may include airplanes, rockets, space shuttles, and spacecraft, etc.
[0075] The features and performance of the present invention will be further described in detail below with reference to embodiments.
[0076] Example 1 This embodiment provides a polycrystalline high-nickel ternary cathode material, the preparation method of which includes: Step (1): Ni cobalt manganese hydroxide precursor Ni 0.94 Co 0.03 Mn 0.03 (OH)₂ was dispersed in water to obtain a suspension of nickel-cobalt-manganese hydroxide precursor with a concentration of 300 g / L. The suspension was mixed with a pore-forming agent solution (lithium sulfate, concentration 0.05 g / L) at a volume ratio of 1:1, and then subjected to an ion exchange reaction for 6 h at 60 °C, pH 10.6, and ammonia concentration of 5 g / L to obtain a nickel-cobalt-manganese hydroxide precursor Ni doped with the pore-forming agent. 0.94 Co 0.03 Mn 0.03 L 0.035 (OH)2. In the above process, the ammonia concentration for the ion exchange reaction is adjusted by adding ammonia water, and the pH value for the coprecipitation reaction is adjusted by adding alkali solution.
[0077] Step (2): Take 4 kg of the nickel-cobalt-manganese hydroxide precursor with surface-doped pore-forming agent and mix it with 2.03 kg of lithium-containing compound (lithium hydroxide monohydrate) by dry ball milling for 5 h to obtain a mixture. The ratio of the total molar amount of nickel, cobalt, and manganese in the nickel-cobalt-manganese hydroxide precursor with surface-doped pore-forming agent to the molar amount of lithium in the lithium-containing compound is 1:1.15. The mixture is then calcined in an oxygen atmosphere at 700°C for 9 h, followed by calcination at 900°C for 2 h, and then calcined at 700°C for 10 h. The heating and cooling rates are both 5°C / min to obtain the first intermediate material.
[0078] Step (3): Take 2.4L of deionized water at 1.5℃, add 800g of aluminum sulfate octadecahydrate, stir with a mechanical stirrer at 200rpm for 10min to obtain a water washing solution; add 4kg of the first intermediate material to the water washing solution, stir for 10min, place it in a centrifuge, centrifuge at 50Hz for 1h, and then place it in a vacuum drying oven to dry at 120℃ for 10h. After the material is completely dry, pass it through a 200-mesh sieve to obtain the second intermediate material.
[0079] Step (4): Dissolve 75g of glucose in 150mL of deionized water, and then use a spraying device to spray it evenly on the surface and pores of 3kg of the second intermediate material. Finally, sinter at 450℃ for 10h under a nitrogen atmosphere to obtain polycrystalline high-nickel ternary cathode material.
[0080] Example 2 The difference between this embodiment and embodiment 1 is that in step (2), the mixture is first calcined at 700°C for 9 hours in an oxygen atmosphere, then calcined at 880°C for 2 hours in a second stage, and then calcined at 700°C for 10 hours in a third stage. The heating rate and cooling rate are both 5°C / min, and the first intermediate material is obtained.
[0081] Example 3 This embodiment provides a polycrystalline high-nickel ternary cathode material, the preparation method of which includes: Step (1): Ni cobalt manganese hydroxide precursor Ni 0.94 Co 0.03 Mn 0.03 (OH)₂ was dispersed in water to obtain a suspension of nickel-cobalt-manganese hydroxide precursor with a concentration of 300 g / L. The suspension was mixed with a pore-forming agent solution (potassium chloride, concentration 0.02 g / L) at a volume ratio of 1:4, and then subjected to an ion exchange reaction for 10 h at 40 °C, pH 10.0, and ammonia concentration of 4 g / L to obtain a nickel-cobalt-manganese hydroxide precursor with surface doped with the pore-forming agent. During the above process, the ammonia concentration for the ion exchange reaction was adjusted by adding ammonia water, and the pH value for the ion exchange reaction was adjusted by adding alkali solution.
[0082] Step (2): The nickel-cobalt-manganese hydroxide precursor with surface-doped pore-forming agent was mixed with a lithium-containing compound (lithium oxalate) by dry ball milling for 5 hours to obtain a mixture. The ratio of the total molar amount of nickel, cobalt, and manganese in the nickel-cobalt-manganese hydroxide precursor with surface-doped pore-forming agent to the molar amount of lithium in the lithium-containing compound was 1:1. The mixture was then calcined in an oxygen atmosphere at 300°C for 10 hours, followed by 750°C for 10 hours, and then 500°C for 15 hours. The heating and cooling rates were both 5°C / min to obtain the first intermediate material.
[0083] Step (3): Take deionized water at 10℃, add sodium chloride, and stir with a mechanical stirrer at 200 rpm for 10 min to obtain a water washing solution; add the first intermediate material to the water washing solution, stir for 10 min, and then place it in a centrifuge at 50 Hz for 1 h, followed by drying in a vacuum drying oven at 100℃ for 20 h. After the material is completely dry, pass it through a 200-mesh sieve to obtain the second intermediate material. The concentration of the metal salt in the water washing solution is 500 g / 3 L, and the mass ratio of the metal salt to the first intermediate material in the water washing solution is 1:2.
[0084] Step (4): Dissolve 50g of glucose in 100mL of deionized water, then spray it evenly onto the surface and pores of the second intermediate material using a spray device. Finally, sinter the mixture at 200℃ for 15h under a nitrogen atmosphere to obtain a polycrystalline high-nickel ternary cathode material. The mass ratio of the second intermediate material to the conductive agent is 3:0.05.
[0085] Example 4 This embodiment provides a polycrystalline high-nickel ternary cathode material, the preparation method of which includes: Step (1): Ni cobalt manganese hydroxide precursor Ni 0.94 Co 0.03 Mn 0.03 (OH)₂ was dispersed in water to obtain a suspension of nickel-cobalt-manganese hydroxide precursor with a concentration of 300 g / L. The suspension was mixed with a pore-forming agent solution (manganese sulfate, concentration 0.1 g / L) at a volume ratio of 1:2, and then subjected to an ion exchange reaction for 3 h at 80 °C, pH 11, and ammonia concentration of 8 g / L to obtain a nickel-cobalt-manganese hydroxide precursor with a surface-doped pore-forming agent. During the above process, the ammonia concentration for the ion exchange reaction was adjusted by adding ammonia water, and the pH value for the ion exchange reaction was adjusted by adding alkali solution.
[0086] Step (2): The nickel-cobalt-manganese hydroxide precursor with surface-doped pore-forming agent was mixed with a lithium-containing compound (lithium citrate) by dry ball milling for 5 hours to obtain a mixture. The molar ratio of the nickel-cobalt-manganese hydroxide precursor with surface-doped pore-forming agent to the lithium element in the lithium-containing compound was 1:2. The mixture was then calcined in an oxygen atmosphere at 750°C for 3 hours, followed by a second stage calcination at 1100°C for 5 hours, and a third stage calcination at 750°C for 10 hours. The heating and cooling rates were both 5°C / min to obtain the first intermediate material.
[0087] Step (3): Take deionized water at 20℃, add manganese sulfate, and stir with a mechanical stirrer at 200 rpm for 10 min to obtain a water washing solution; add the first intermediate material to the water washing solution, stir for 10 min, and then place it in a centrifuge and centrifuge at 50 Hz for 1 h, and then place it in a vacuum drying oven and dry at 180℃ for 2 h. After the material is completely dry, pass it through a 200-mesh sieve to obtain the second intermediate material. The concentration of the metal salt in the water washing solution is 1500 g / 3 L, and the mass ratio of the metal salt in the water washing solution to the first intermediate material is 1:10.
[0088] Step (4): Dissolve 250g of glucose in 500mL of deionized water, then spray it evenly onto the surface and pores of the second intermediate material using a spray device. Finally, sinter the mixture at 500℃ for 3 hours under a nitrogen atmosphere to obtain a polycrystalline high-nickel ternary cathode material. The mass ratio of the second intermediate material to the conductive agent is 3:0.1.
[0089] Comparative Example 1 The difference between this comparative example and Example 1 is that in step (2), calcination is carried out only in an oxygen atmosphere, with a heating rate of 5°C / min to 700°C and held for 20 hours.
[0090] Comparative Example 2 The difference between this comparative example and Example 1 is that in step (2), calcination is carried out only in an oxygen atmosphere, with a heating rate of 5℃ / min to 900℃ and held for 20h.
[0091] Comparative Example 3 This comparative example is the first intermediate material obtained in step (2) of Example 1.
[0092] Comparative Example 4 This comparative example provides a ternary cathode material, the preparation method of which includes: Step (1): Take 4 kg of nickel-cobalt-manganese hydroxide precursor Ni 0.94 Co 0.03 Mn 0.03(OH)₂ was mixed with 2.03 kg of a lithium-containing compound (lithium hydroxide monohydrate) by dry ball milling for 5 h to obtain a mixture. The mixture was then subjected to a first-stage calcination at 700 °C for 9 h in an oxygen atmosphere, followed by a second-stage calcination at 900 °C for 2 h, and a third-stage calcination at 700 °C for 10 h, with a heating and cooling rate of 5 °C / min, to obtain an intermediate material.
[0093] Step (2): Take 2.4L of deionized water at 0.5℃, add 800g of aluminum sulfate octadecahydrate, stir with a mechanical stirrer at 200rpm for 10min to obtain a water washing solution; add 4kg of intermediate material to the water washing solution, stir for 10min, place in a centrifuge, centrifuge at 50Hz for 1h, and then place in a vacuum drying oven to dry at 120℃ for 10h. After the material is completely dry, pass through a 200-mesh sieve to obtain ternary cathode material.
[0094] That is, no pores were created in the precursor in this comparative example, and no conductive agent was used.
[0095] Comparative Example 5 The difference between this comparative example and Example 1 is that in step (3), pure water is used to clean the first intermediate material.
[0096] Comparative Example 6 The difference between this comparative example and Example 1 is that in step (1), the volume ratio of the suspension to the pore-forming agent solution is 1:0.5.
[0097] Comparative Example 7 The difference between this comparative example and Example 1 is that in step (1), the volume ratio of the suspension to the pore-forming agent solution is 1:5.
[0098] Test case (1) The polycrystalline high-nickel ternary cathode material prepared in Example 1 was characterized by SEM and XRD, and the results are as follows: Figures 1 to 3 As shown.
[0099] Figure 1 and Figure 2 The ternary cathode material prepared from the nickel-cobalt-manganese hydroxide precursor doped with a pore-forming agent has pores on both its surface and inside.
[0100] Depend on Figure 3 It can be seen that glucose carbonizes the material surface without reducing lithium nickel cobalt manganese oxide, and no impurity peaks appear in the XRD data.
[0101] (2) The performance of the ternary cathode materials prepared in Examples 1-4 and Comparative Examples 1-7 was tested, and the results are shown in Table 1 and... Figure 4 As shown.
[0102] Porosity was measured using ImageJ software, lithium-nickel hybridization was determined by XRD pattern analysis using Jade 6.0 software, specific surface area (BET) was measured using a specific surface area analyzer, and particle size Dn was measured. 10 and D 50 All values were measured using a particle size analyzer, and the carbon content was measured using a carbon-sulfur analyzer.
[0103] The discharge capacity was obtained by preparing a battery using various ternary cathode materials in the following manner and then testing it. The battery preparation method is as follows: High-nickel ternary cathode materials were used as active materials, acetylene black as a conductive agent, and polyvinylidene fluoride (PVDF) as a binder, weighed in a mass ratio of 90:5:5 to form electrode sheets. Using these electrode sheets as the positive electrode and lithium metal sheets as the negative electrode, CR2430 button batteries were assembled in a glove box filled with high-purity argon gas. The capacity testing conditions included: using a Blue Electric Tester (CT2001A) to test the electrical performance of the assembled batteries under the following conditions: 2.8V~4.3V, 0.1C (1C=220mA / g) for 1 cycle and 80 cycles.
[0104] Table 1 Performance Data
[0105] As can be seen from Table 1: Examples 1-4 all use nickel-cobalt-manganese hydroxide precursors with surface-doped pore-forming agents. Under rapid calcination, the pore-forming agents penetrate into the material, creating numerous pores on the material surface and inside. A specific metal salt solution is used to wash away the pore-forming agents inside the material, while depositing them on the material surface to provide protection and reduce primary particle detachment. After water washing, a glucose solution is sprayed on, followed by sintering and carbonization. This stabilizes the structure and improves the conductivity of the polycrystalline high-nickel ternary material, resulting in batteries corresponding to the polycrystalline high-nickel ternary cathode materials of Examples 1-4 having higher discharge capacity and better cycle performance.
[0106] Comparing Example 1 and Comparative Example 1, since the pore-forming agent has a high melting point, Comparative Example 1, using a normal sintering temperature, failed to create pores inside the material, and the capacity was not improved.
[0107] By comparing Example 1 and Comparative Example 2, Comparative Example 2 uses a temperature higher than the melting point of the pore-forming agent, which can create pores inside the material. However, due to the excessively high sintering temperature, the primary particles are too large, which seriously affects the material's capacity utilization.
[0108] Comparing Example 1 and Comparative Example 3, Comparative Example 3 did not remove the sulfate ions introduced for pore formation. Excessive sulfate impurities within the material hindered lithium ion insertion and extraction during the charging and discharging process, resulting in a significantly lower capacity. Although no carbon coating was applied in Comparative Example 3, residual lithium on the material surface reacted with CO2 in the air, leading to the detection of carbon content.
[0109] Comparing Example 1 and Comparative Example 4, Comparative Example 4, which uses short-time high-temperature sintering, shows a significantly lower degree of lithium-nickel mixing compared to the comparative example using a single sintering platform. No pore-forming agent was added during the sintering process, resulting in a lack of pores within the material. This hinders lithium-ion insertion and extraction during the charging and discharging process, leading to a relatively low capacity. Furthermore, the lack of pores also causes excessive internal stress during cycling, resulting in mediocre cycling performance.
[0110] By comparing Example 1 and Comparative Example 5, Comparative Example 5 used water to wash the material. Due to the lack of anionic sulfate ions in the water, which are the same as those in the pore-forming agent, and the absence of cations that could be deposited on the material surface, the material experienced severe primary particle detachment, and the Dn10 was significantly smaller. Although the capacity was relatively high, the excessive micropowder deteriorated the cycle performance.
[0111] By comparing Example 1 and Comparative Examples 6-7, it was found that both excessively low and excessively high volume ratios of suspension to pore-forming agent solution would reduce the discharge capacity of batteries prepared from the corresponding ternary cathode materials.
[0112] In summary, the polycrystalline high-nickel ternary cathode material provided by this invention contains pores that allow space for expansion during cycling, reducing material breakage and enhancing cycling performance. Furthermore, the conductive agent is present at least on the surface of the polycrystalline high-nickel ternary cathode material, which not only helps stabilize the structure and optimize current conduction, but also enables more efficient charge transfer and improved electrochemical performance during charging and discharging.
[0113] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A polycrystalline high-nickel ternary cathode material, characterized in that, The polycrystalline high-nickel ternary cathode material includes a polycrystalline high-nickel ternary cathode material body, at least a portion of the surface and at least a portion of the internal region of the polycrystalline high-nickel ternary cathode material body having pores, and at least the surface of the polycrystalline high-nickel ternary cathode material body having a conductive agent.
2. The polycrystalline high-nickel ternary cathode material according to claim 1, characterized in that, The polycrystalline high-nickel ternary cathode material also has at least one of the following characteristics: Feature 1: The general formula of the polycrystalline high-nickel ternary cathode material is LiNi. x Co y Mn z O2, where x≥0.6, y≥0, z≥0, x+y+z=1; Feature 2: The conductive agent includes at least one of carbon nanotubes, flake graphite, conductive fibers, and amorphous carbon; Feature 3: The Dv of the polycrystalline high-nickel ternary cathode material 50 The thickness ranges from 7μm to 12μm. Feature 4: The porosity of the polycrystalline high-nickel ternary cathode material is 1.5%~3.5%; Feature 5: The pore size of the pores in the internal region of the polycrystalline high-nickel ternary cathode material is 0.2μm~1.0μm; Feature 6: The lithium-nickel mixing ratio of the polycrystalline high-nickel ternary cathode material is 1.89%~1.96%; Feature 7: The specific surface area of the polycrystalline high-nickel ternary cathode material is 0.95 m². 2 / g~1.05m 2 / g; Feature 8: The Dn of the polycrystalline high-nickel ternary cathode material 10 The thickness is 3.30μm~3.35μm; Feature 9: The carbon content of the polycrystalline high-nickel ternary cathode material is 1%~3%.
3. A method for preparing a polycrystalline high-nickel ternary cathode material as described in claim 1 or 2, characterized in that, The process includes the following steps: mixing a nickel-cobalt-manganese hydroxide precursor with a surface-doped pore-forming agent with a lithium-containing compound, followed by calcination to obtain a first intermediate material; The first intermediate material is cleaned with a water washing solution, followed by solid-liquid separation and drying to obtain the second intermediate material; the second intermediate material is mixed with a carbon source for forming a conductive agent and sintered to obtain a polycrystalline high-nickel ternary cathode material.
4. The preparation method according to claim 3, characterized in that, The preparation of the nickel cobalt manganese hydroxide precursor with surface doped pore-forming agent includes: mixing a suspension of the nickel cobalt manganese hydroxide precursor with a pore-forming agent solution, and then carrying out an ion exchange reaction under the conditions of a temperature of 40℃~80℃, a pH value of 10.0~11.0, and an ammonia concentration of 4g / L~8g / L. Preferably, the ion exchange reaction time is 3h to 10h.
5. The preparation method according to claim 4, characterized in that, The volume ratio of the suspension to the pore-forming agent solution is 1:1 to 1:4, wherein the concentration of the nickel cobalt manganese hydroxide precursor in the suspension is 100 g / L to 800 g / L, and the concentration of the pore-forming agent in the pore-forming agent solution is 0.01 g / L to 0.1 g / L. Preferably, the concentration of the pore-forming agent in the pore-forming agent solution is 0.02 g / L to 0.05 g / L; Preferably, the pore-forming agent comprises at least one of a metal sulfate and a metal hydrochloride; Preferably, the pore-forming agent includes at least one of potassium sulfate, sodium sulfate, lithium sulfate, aluminum sulfate, cobalt sulfate, manganese sulfate, nickel sulfate, zinc sulfate, copper sulfate, ferric sulfate, potassium chloride, sodium chloride, lithium chloride, aluminum chloride, cobalt chloride, manganese chloride, nickel chloride, zinc chloride, copper chloride, and ferric chloride.
6. The preparation method according to claim 3, characterized in that, The preparation of the first intermediate material includes at least one of the following features: Feature 10: The lithium-containing compound includes at least one of lithium oxalate, lithium carbonate, lithium hydroxide monohydrate, lithium acetate, and lithium citrate; Feature 11: The ratio of the total molar amount of nickel, cobalt, and manganese in the nickel-cobalt-manganese hydroxide precursor doped with the pore-forming agent to the molar amount of lithium in the lithium-containing compound is 1:1 to 1:1.2; Feature 12: The calcination includes: first stage calcination at 300℃~750℃, second stage calcination at 800℃~1100℃, and third stage calcination at 500℃~750℃. Preferably, the holding time for the first stage of calcination is 3h to 10h, the holding time for the second stage of calcination is no more than 10h, and the holding time for the third stage of calcination is 10h to 15h.
7. The preparation method according to claim 5, characterized in that, The preparation of the second intermediate material includes at least one of the following features: Feature 13: The washing solution is an aqueous solution of a metal salt, and the concentration of the metal salt in the washing solution is 500g / 3L to 1500g / 3L; the mass ratio of the metal salt to the first intermediate material in the washing solution is 1:2 to 1:10; Feature 14: The washing solution is an aqueous solution of a metal salt, wherein the anion of the metal salt in the aqueous solution is the same as the anion of the pore-forming agent in the pore-forming agent solution; preferably, the metal salt includes at least one of potassium sulfate, sodium sulfate, lithium sulfate, aluminum sulfate, cobalt sulfate, manganese sulfate, nickel sulfate, zinc sulfate, copper sulfate, and ferric sulfate; feature 15: The temperature of the washing solution is 1.5℃~20℃; Feature 16: Drying temperature is 100℃~180℃, and drying time is 2h~20h.
8. The preparation method according to claim 4, characterized in that, The preparation of the polycrystalline high-nickel ternary cathode material includes at least one of the following characteristics: Feature 17: The mass ratio of the second intermediate material to the conductive agent is 3:0.05 to 3:0.1; Feature 18: Glucose is applied to the second intermediate material in solution form by spraying, and then sintered to form amorphous carbon; Feature 19: Sintering temperature is 200℃~500℃, sintering time is 3h~15h.
9. A battery, characterized in that, The battery contains the polycrystalline high-nickel ternary cathode material as described in claim 1 or 2.
10. An electrical appliance, characterized in that, The electrical device includes the battery as described in claim 9.