Method for synthesizing ternary precursor under assistance of electric pulses and use

Abstract

Disclosed are a method for synthesizing a ternary precursor under assistance of electric pulses and a use. According to the present disclosure, under the action of electric pulses, a coprecipitation reaction slows down the growth speed of a crystal nucleus without using a complexing agent, so that the obtained crystal grains are finer, and have higher sphericity; and the presence of the electric pulses in the aging process can also make the growth of the crystal grains more uniform and denser.

Description

Method and application of electric pulse assisted synthesis of ternary precursors Technical Field

[0001] The present disclosure relates to the technical field of cathode materials, and in particular to a method and application of electric pulse-assisted synthesis of ternary precursors. Background Art

[0002] With the development of the new energy vehicle industry, lithium-ion batteries have emerged as a leader among various battery types due to their advantages, including stable voltage, high capacity, high energy density, long cycle life, and environmental friendliness. The key factor determining lithium-ion battery performance is the electrochemical properties of the cathode material. For ternary cathode materials, the quality and physicochemical properties of the precursors largely determine their performance.

[0003] There are many methods for preparing ternary precursors, such as solid phase method, spray drying method, co-precipitation method, etc. Compared with other precursor synthesis methods, co-precipitation method is easy to operate and has high product quality, so it is widely used in ternary precursor synthesis. In order to improve the electrical properties of the positive electrode material, the tap density of the positive electrode material is usually improved as much as possible, but if the surface of the precursor is too dense, it will make it difficult for lithium ions to diffuse into the interior of the precursor, affecting the capacity of the positive electrode material, such as the ternary precursor disclosed in Chinese patent CN108615868B; and although the surface is too loose, it is conducive to the diffusion of lithium ions, but over-burning may occur during the sintering process, thereby causing the material structure to collapse and affecting the cycle performance. Therefore, precise control of the precursor co-precipitation process is particularly important, such as the precursor material disclosed in Chinese patent CN111682199A. Therefore, how to adjust the density of the positive electrode material to take into account both capacity and cycle performance is particularly necessary.

[0004] In view of this, the present disclosure is proposed.

[0005] Summary of the Invention

[0006] The purpose of the present disclosure is to provide a method for the electric pulse assisted synthesis of a ternary precursor and a method for preparing a ternary material, thereby improving the sphericity of the ternary positive electrode precursor particles synthesized by the co-precipitation method, which is beneficial to improving the tap density of the prepared positive electrode material.

[0007] The present disclosure is achieved as follows:

[0008] In a first aspect, the present disclosure provides a method for the electric pulse-assisted synthesis of a ternary precursor, comprising: placing a first mixed solution containing a nickel salt, a cobalt salt, a manganese salt and a first precipitant in an electric pulse and protective atmosphere environment for a co-precipitation reaction until the precipitated particles grow to a D50 of 3 μm to 5 μm, then adding a complexing agent and a second precipitant to the reaction system to obtain a second mixed solution, placing the second mixed solution in an electric pulse environment for aging to obtain a solid-liquid mixture containing ternary precursor particles.

[0009] In some embodiments, the number of pulses of the electric pulse signal in the coprecipitation step is 5 times / s to 20 times / s, and the frequency is 3kHz to 30kHz; and / or, the number of pulses of the electric pulse signal in the aging step is 5 times / s to 20 times / s, and the frequency is 3kHz to 30kHz.

[0010] In some embodiments, the coprecipitation reaction and the aging step are both performed in a reactor, and the electric pulse generating device is installed on the outer wall of the reactor.

[0011] In some embodiments, the electric pulse generating device is installed on the outer wall of one side of the feed port.

[0012] In some embodiments, the electric pulse generating device is a Vulcan S100 electric pulse descaling device.

[0013] In some embodiments, the nickel salt is at least one of nickel nitrate, nickel sulfate, nickel chloride, nickel oxalate, and nickel acetate.

[0014] In some embodiments, the cobalt salt is at least one of cobalt nitrate, cobalt sulfate, cobalt chloride, cobalt oxalate, and cobalt acetate.

[0015] In some embodiments, the manganese salt is at least one of manganese nitrate, manganese sulfate, manganese chloride, manganese oxalate, and manganese acetate.

[0016] In some embodiments, the first precipitant is at least one of sodium hydroxide, potassium hydroxide, and lithium hydroxide; and / or the second precipitant is at least one of sodium hydroxide, potassium hydroxide, and lithium hydroxide.

[0017] In some embodiments, the total concentration of nickel ions, cobalt ions, and manganese ions in the first mixed solution is 1 mol / L to 3 mol / L.

[0018] In some embodiments, the protective atmosphere is at least one of nitrogen and argon.

[0019] In some embodiments, the coprecipitation reaction is carried out under stirring conditions at a stirring speed of 100 r / min to 1000 r / min.

[0020] In some embodiments, the coprecipitation reaction temperature is 40° C. to 65° C., and the pH is 11-13.

[0021] In some embodiments, the complexing agent is at least one of ammonia, EDTA, EDTA disodium salt, citric acid, ammonium carbonate, potassium sodium tartrate, and ammonium bicarbonate.

[0022] In some embodiments, the content of the complexing agent in the second mixed solution is 2 g / L to 5 g / L.

[0023] In some embodiments, the aging step is performed at a temperature of 40° C. to 65° C., a pH of 9-11, and a time of 2 h to 15 h.

[0024] In some embodiments, the solid-liquid mixture containing the ternary precursor particles is subjected to solid-liquid separation, and the solid phase is washed with water and dried to obtain the ternary precursor.

[0025] In some embodiments, the drying temperature is 50° C. to 70° C., and the drying time is 6 h to 24 h.

[0026] In a second aspect, the present disclosure provides a method for preparing a ternary material, wherein the ternary material is prepared using the ternary precursor described in any one of the aforementioned embodiments as a raw material.

[0027] The present disclosure has the following beneficial effects:

[0028] The present invention introduces electric pulses in the process of preparing precursors by the co-precipitation method, so that water is broken into single water molecules under the action of the electric pulses. The polar water molecules are wrapped around the positive and negative ions, which reduces the chance of collision between the positive and negative ions, thereby suppressing the reaction rate during co-precipitation and reducing the use of complexing agents in the synthesis process.

[0029] The present invention discloses that under the action of electric pulses, the coprecipitation reaction slows down the growth rate of the crystal nucleus without using a complexing agent, so that the obtained grains are finer and have higher sphericity; the presence of electric pulses during the aging process can also make the grain growth more uniform and dense. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present disclosure and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0031] FIG1 is a flow chart of Example 1;

[0032] FIG2 is a 5000-fold electron microscope image of the method for obtaining the ternary precursor in Example 1;

[0033] FIG3 is an electron microscope image of the method for obtaining the ternary precursor in Example 1 at a magnification of 10,000 times;

[0034] FIG4 is an electron microscope image of the method for obtaining the ternary precursor in Example 1 at a magnification of 50,000 times. DETAILED DESCRIPTION

[0035] To make the purpose, technical solutions, and advantages of the embodiments of the present disclosure more clear, the technical solutions in the embodiments of the present disclosure are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer were followed. Reagents or instruments used where the manufacturer is not specified are conventional products that can be purchased commercially.

[0036] The present disclosure provides a method for synthesizing a ternary precursor with the assistance of electric pulses, comprising: placing a first mixed solution containing a nickel salt, a cobalt salt, a manganese salt and a first precipitant in an electric pulse and protective atmosphere environment for a co-precipitation reaction until the precipitated particles grow to a D50 of 3 μm to 5 μm, then adding a complexing agent and a second precipitant to the reaction system to obtain a second mixed solution, placing the second mixed solution in an electric pulse environment for aging, and obtaining a solid-liquid mixture containing ternary precursor particles.

[0037] This embodiment introduces electric pulses in the process of preparing precursors by the co-precipitation method, so that water is broken into single water molecules under the action of the electric pulses. The polar water molecules are wrapped around the positive and negative ions, which reduces the chance of collision between the positive and negative ions, thereby suppressing the reaction rate during co-precipitation and reducing the use of chelating agents in the synthesis process.

[0038] If the surface of the precursor is too dense, it will make it difficult for lithium ions to diffuse into the interior of the precursor, affecting the capacity of the positive electrode material. Although a surface that is too loose is conducive to the diffusion of lithium ions, over-burning may occur during the sintering process, causing the material structure to collapse and affecting the cycle performance. In order to overcome the above problems, this embodiment prepares a ternary precursor with a high core density that can guarantee the capacity to a certain extent, a denser surface, and a balance between capacity and cycle performance: Under the action of an electric pulse, the coprecipitation reaction in this embodiment slows down the growth rate of the crystal nucleus without using a complexing agent, so that the obtained grains are finer, the sphericity is higher, and the core is more uniform and dense, with a particle size of 3μm to 5μm; then aging is carried out, and a complexing agent is added during the aging process to increase the precipitation rate. At the same time, with the electric pulse, the grain growth is more uniform and dense, and a ternary precursor with a particle size of more than ten microns is obtained.

[0039] In this embodiment, the ternary precursor with a particle size of 3μm to 5μm is obtained by coprecipitation reaction and then aged. Specifically, the aging can be carried out after the particle size of the ternary precursor grows to 3μm, 3.5μm, 4μm, 4.5μm, 5μm or any value between 3μm and 5μm. In this way, on the one hand, the interior of the precursor is more uniform and dense, and on the other hand, the surface of the precursor will not be too dense to affect the diffusion of lithium ions, nor will it be too loose to reduce the cycle performance.

[0040] In some embodiments, the number of pulses of the electric pulse signal in the coprecipitation step is 5 times / s to 20 times / s, and the frequency is 3kHz to 30kHz; and / or, the number of pulses of the electric pulse signal in the aging step is 5 times / s to 20 times / s, and the frequency is 3kHz to 30kHz. The number of pulses of the electric pulse signal is 5 times / s to 20 times / s, specifically, the number of pulses can be 5 times / s, 10 times / s, 15 times / s, 20 times / s, or any value between 5 times / s and 20 times / s; the frequency is 3kHz to 30kHz, specifically, it can be 3kHz, 10kHz, 15kHz, 20kHz, 30kHz, or any value between 3kHz and 30kHz. The number of pulses of the electric pulse signal in the coprecipitation step and the aging step can be the same or different.

[0041] In this embodiment, increasing the number of pulses and the frequency can reduce the precipitation rate and obtain a relatively dense precursor material. Therefore, the density of the precursor material can be adjusted by adjusting the frequency and number of pulses of the electric pulse. However, excessive density affects the diffusion of lithium ions. Preferably, the number of pulses of the electric pulse signal in the co-precipitation step is 10 times / s to 15 times / s, and the frequency is 10kHz to 20kHz; and / or, the number of pulses of the electric pulse signal in the aging step is 10 times / s to 15 times / s, and the frequency is 10kHz to 20kHz.

[0042] In some embodiments, the coprecipitation reaction and the aging step are both performed in a reactor, and the electric pulse generating device is installed on the outer wall of the reactor.

[0043] In some embodiments, the electric pulse generating device is installed on the outer wall on one side of the feed port. The electric pulse generating device is installed as close to the feed port as possible, which is conducive to the material entering the electric pulse environment as soon as possible after entering the reactor.

[0044] In some embodiments, the electric pulse generating device is a Vulcan S100 electric pulse descaling device.

[0045] In some embodiments, the nickel salt is at least one of nickel nitrate, nickel sulfate, nickel chloride, nickel oxalate, and nickel acetate.

[0046] In some embodiments, the cobalt salt is at least one of cobalt nitrate, cobalt sulfate, cobalt chloride, cobalt oxalate, and cobalt acetate.

[0047] In some embodiments, the manganese salt is at least one of manganese nitrate, manganese sulfate, manganese chloride, manganese oxalate, and manganese acetate.

[0048] In some embodiments, the first precipitant is at least one of sodium hydroxide, potassium hydroxide, and lithium hydroxide; and / or the second precipitant is at least one of sodium hydroxide, potassium hydroxide, and lithium hydroxide. The first precipitant and the second precipitant may be the same or different.

[0049] In some embodiments, the total concentration of nickel ions, cobalt ions, and manganese ions in the first mixed solution is 1 mol / L to 3 mol / L, specifically, 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L, 3 mol / L, or any value between 1 mol / L and 3 mol / L.

[0050] The total concentration of nickel ions, cobalt ions, and manganese ions will affect the precipitation rate, so they need to be reasonably selected. The ratio of nickel ions, cobalt ions, and manganese ions can be determined according to the composition of the target precursor material, for example, the molar ratio of Ni, Mn, and Co is 6:2:2, 7:1.5:1.5, 8:1:1, and 9:0.5:0.5.

[0051] In some embodiments, the protective atmosphere is at least one of nitrogen and argon, for example, nitrogen, argon, or a mixture of nitrogen and argon.

[0052] In some embodiments, the coprecipitation reaction is carried out under stirring conditions, and the stirring speed is 100 r / min to 1000 r / min, specifically, it can be 100 r / min, 400 r / min, 700 r / min, 1000 r / min or any value between 100 r / min and 1000 r / min.

[0053] Stirring is beneficial to the uniform distribution of the components in the reaction system, and is also beneficial to obtaining precursor particles with relatively uniform particle size in the co-precipitation step.

[0054] In some embodiments, the coprecipitation reaction temperature is 40°C to 65°C, specifically, it can be 40°C, 45°C, 50°C, 55°C, 60°C, 65°C or any value between 40°C and 65°C; the pH is 11 to 13, specifically, it can be 11, 11.5, 12, 12.5, 13 or any value between 11 and 13.

[0055] In some embodiments, the complexing agent is at least one of ammonia, EDTA, EDTA disodium salt, citric acid, ammonium carbonate, potassium sodium tartrate, and ammonium bicarbonate.

[0056] In some embodiments, the content of the complexing agent in the second mixed solution is 2 g / L to 5 g / L, specifically, it can be 2 g / L, 3 g / L, 4 g / L, 5 g / L or any value between 2 g / L and 5 g / L. In this embodiment, increasing the amount of complexing agent added is conducive to obtaining a denser precursor, but if the amount of complexing agent added is too large, the metal ion precipitation will be incomplete, so it should not exceed 5 g / L.

[0057] In some embodiments, the temperature of the aging step is 40°C to 65°C, specifically, it can be 40°C, 45°C, 50°C, 55°C, 60°C, 65°C or any value between 40°C and 65°C; the pH is 9-11, specifically, it can be 9, 9.5, 10, 10.5, 11 or any value between 9 and 11; the time is 2h, 5h, 8h, 12h, 15h, specifically, it can be 2h to 15h or any value between 2h and 15h.

[0058] In some embodiments, the solid-liquid mixture containing the ternary precursor particles is subjected to solid-liquid separation, and the solid phase is washed with water and dried to obtain the ternary precursor.

[0059] In some embodiments, the drying temperature is 50°C to 70°C, specifically, it can be 50°C, 55°C, 60°C, 65°C, 70°C or any value between 50°C and 70°C; the drying time is 6h to 24h, specifically, it can be 6h, 12h, 18h, 24h or any value between 6h and 24h.

[0060] In a second aspect, the present disclosure provides a method for preparing a ternary material, wherein the ternary material is prepared using the ternary precursor described in any one of the aforementioned embodiments as a raw material.

[0061] The features and performance of the present disclosure are further described in detail below with reference to the embodiments.

[0062] Example 1:

[0063] This embodiment provides a method for synthesizing a ternary precursor by electric pulse assistance, as shown in FIG1 , comprising the following steps:

[0064] S1: Prepare a mixed metal salt solution of nickel chloride, cobalt chloride, and manganese chloride at a molar ratio of 6:2:2 (nickel:cobalt:manganese) to a concentration of 2 mol / L. Prepare a sodium hydroxide solution and an ammonia solution at a concentration of 5 mol / L.

[0065] S2: The mixed metal salt solution and sodium hydroxide solution from step S1 were added to a reactor. The electric pulse device was activated and nitrogen was introduced. The pH was adjusted to 11 for a coprecipitation reaction. The reaction temperature was controlled at 50°C and the stirring speed was 300 r / min. The electric pulse device emitted an electric pulse signal at a rate of 10 pulses / s and a frequency of 10 kHz. The electric pulse device was placed on the outer wall of the reactor near the feed port. The particle size was measured using a laser particle size analyzer. The reaction was stopped when the particle size reached 3 μm.

[0066] S3: After the reaction in step S2 is completed, add ammonia solution and sodium hydroxide solution, control the pH to 9, the ammonia content to 3g / L, age for 10h, then perform solid-liquid separation to obtain the ternary precursor to be washed, and turn off the electric pulse device.

[0067] S4: The precursor obtained by solid-liquid separation was washed with deionized water and finally dried at 60° C. for 20 h.

[0068] Example 2:

[0069] This embodiment provides a method for synthesizing a ternary precursor with the assistance of electric pulses, comprising the following steps:

[0070] S1: Prepare a mixed metal salt solution of nickel chloride, cobalt chloride, and manganese chloride at a molar ratio of 6:2:2 (nickel:cobalt:manganese) to a concentration of 2 mol / L. Prepare a sodium hydroxide solution and an ammonia solution at a concentration of 5 mol / L.

[0071] S2: The mixed metal salt solution and sodium hydroxide solution from step S1 were added to a reactor. The electric pulse device was activated and nitrogen was introduced. The pH was adjusted to 11 for a coprecipitation reaction. The reaction temperature was controlled at 50°C and the stirring speed was 300 r / min. The electric pulse device emitted an electric pulse signal at a rate of 5 pulses / s and a frequency of 15 kHz. The electric pulse device was placed on the outer wall of the reactor near the feed port. The reaction was stopped when the particle size grew to 3 μm.

[0072] S3: After the reaction in step S2 is completed, add ammonia solution and sodium hydroxide solution, control the pH to 9, the ammonia content to 3g / L, age for 10h, then perform solid-liquid separation to obtain the ternary precursor to be washed, and turn off the electric pulse device.

[0073] S4: The precursor obtained by solid-liquid separation was washed with deionized water and finally dried at 60° C. for 20 h.

[0074] Example 3:

[0075] This embodiment provides a method for synthesizing a ternary precursor with the assistance of electric pulses, comprising the following steps:

[0076] S1: Prepare a mixed metal salt solution of nickel chloride, cobalt chloride, and manganese chloride at a molar ratio of 6:2:2 (nickel:cobalt:manganese) to a concentration of 2 mol / L. Prepare a sodium hydroxide solution and an ammonia solution at a concentration of 5 mol / L.

[0077] S2: The mixed metal salt solution and sodium hydroxide solution from step S1 were added to a reactor. The electric pulse device was activated and nitrogen was introduced. The pH was adjusted to 11 for a coprecipitation reaction. The reaction temperature was controlled at 50°C and the stirring speed was 300 r / min. The electric pulse device emitted an electric pulse signal at a rate of 20 pulses / s and a frequency of 30 kHz. The electric pulse device was placed on the outer wall of the reactor near the feed port. The reaction was stopped when the particle size grew to 3 μm.

[0078] S3: After the reaction in step S2 is completed, add ammonia solution and sodium hydroxide solution, control the pH to 9, the ammonia content to 3g / L, age for 10h, then perform solid-liquid separation to obtain the ternary precursor to be washed, and turn off the electric pulse device.

[0079] S4: The precursor obtained by solid-liquid separation was washed with deionized water and finally dried at 60° C. for 20 h.

[0080] Example 4:

[0081] This embodiment provides a method for synthesizing a ternary precursor with the assistance of electric pulses, comprising the following steps:

[0082] S1: Prepare a mixed metal salt solution of nickel chloride, cobalt chloride, and manganese chloride at a molar ratio of 6:2:2 (nickel:cobalt:manganese) to a concentration of 2 mol / L. Prepare a sodium hydroxide solution and an ammonia solution at a concentration of 5 mol / L.

[0083] S2: The mixed metal salt solution and sodium hydroxide solution from step S1 were added to a reactor. The electric pulse device was activated and nitrogen was introduced. The pH was adjusted to 13 for a coprecipitation reaction. The reaction temperature was controlled at 40°C and the stirring speed was 100 r / min. The electric pulse device emitted an electric pulse signal at a rate of 20 pulses / s and a frequency of 30 kHz. The electric pulse device was placed on the outer wall of the reactor near the feed port. The reaction was stopped when the particle size grew to 5 μm.

[0084] S3: After the reaction in step S2 is completed, add ammonia solution and sodium hydroxide solution, control the pH to 11, the ammonia content to 2 g / L, age for 2 hours, then perform solid-liquid separation to obtain the ternary precursor to be washed, and turn off the electric pulse device.

[0085] S4: The precursor obtained by solid-liquid separation was washed with deionized water, and finally dried at 50° C. for 20 h.

[0086] Example 5:

[0087] This embodiment provides a method for synthesizing a ternary precursor with the assistance of electric pulses, comprising the following steps:

[0088] S1: Prepare a mixed metal salt solution of nickel chloride, cobalt chloride, and manganese chloride at a molar ratio of 6:2:2 (nickel:cobalt:manganese) to a concentration of 2 mol / L. Prepare a sodium hydroxide solution and an ammonia solution at a concentration of 5 mol / L.

[0089] S2: The mixed metal salt solution and sodium hydroxide solution from step S1 were added to a reactor. The electric pulse device was activated and nitrogen was introduced. The pH was adjusted to 12 for a coprecipitation reaction. The reaction temperature was controlled at 65°C and the stirring speed was 1000 r / min. The electric pulse device emitted an electric pulse signal at a rate of 20 pulses / s and a frequency of 30 kHz. The electric pulse device was placed on the outer wall of the reactor near the feed port. The reaction was stopped when the particle size grew to 4 μm.

[0090] S3: After the reaction in step S2 is completed, add ammonia solution and sodium hydroxide solution, control the pH to 10, the ammonia content to 2 g / L, age for 15 hours, then perform solid-liquid separation to obtain the ternary precursor to be washed, and turn off the electric pulse device.

[0091] S4: The precursor obtained by solid-liquid separation was washed with deionized water and finally dried at 70° C. for 20 h.

[0092] Example 6:

[0093] This comparative example provides a method for synthesizing a ternary precursor with the assistance of electric pulses. The only difference from Example 1 is that the number of electric pulse signals emitted by the electric pulse device is 50 times / s.

[0094] Example 7:

[0095] This comparative example provides a method for synthesizing a ternary precursor with the assistance of electric pulses. The only difference from Example 1 is that the number of pulses of the electric pulse signal emitted by the electric pulse device is 50 kHz.

[0096] Comparative Example 1:

[0097] This comparative example provides a method for synthesizing a ternary precursor, comprising the following steps:

[0098] S1: Prepare a mixed metal salt solution of nickel chloride, cobalt chloride, and manganese chloride at a molar ratio of 6:2:2 (nickel:cobalt:manganese) to a concentration of 2 mol / L. Prepare a sodium hydroxide solution and an ammonia solution at a concentration of 5 mol / L.

[0099] S2: Add the mixed metal salt solution and sodium hydroxide in step S1 into the reactor, adjust the pH to 11 to carry out coprecipitation reaction, stop the reaction when the particle size grows to 3 μm, and control the reaction temperature to 50° C. and the stirring speed to 300 r / min.

[0100] S3: After the reaction of S2 is completed, ammonia solution and sodium hydroxide are added to control the pH to 9 and the ammonia content to 3 g / L. The mixture is aged for 10 hours and then solid-liquid separation is performed to obtain the ternary precursor to be washed.

[0101] S4: The precursor obtained by solid-liquid separation was washed with deionized water and finally dried at 60° C. for 20 h.

[0102] Comparative Example 2:

[0103] This comparative example provides a method for synthesizing a ternary precursor with the assistance of electric pulses, which differs from Example 1 only in that, in step S2, the co-precipitation reaction is stopped when the precipitate particle size grows to 1.5 μm.

[0104] Comparative Example 3:

[0105] This comparative example provides a method for synthesizing a ternary precursor with the assistance of electric pulses. The only difference from Example 1 is that in step S2, the co-precipitation reaction is stopped when the precipitate particle size grows to 7 μm.

[0106] Test Example 1

[0107] The compaction density of the ternary precursors obtained in the examples and comparative examples was tested using an electric powder tablet press (instrument model: MSK-YLJ-E30T, China Kejing). The test results are shown in the table below.

[0108] Test Example 2

[0109] The ternary precursors obtained in the examples and comparative examples were prepared as ternary positive electrode materials, which were then assembled into batteries to test the capacity and cycle performance of the positive electrode materials. The test results are shown in the table below.

[0110] The preparation steps of the ternary positive electrode material are as follows: the ternary precursor and lithium hydroxide are evenly mixed in a molar ratio of Li: (Ni+Co+Mn) = 1.02:1, calcined at 500°C in an oxygen atmosphere for 5 hours, and then heated to 800°C and calcined for 12 hours to obtain the ternary positive electrode material.

[0111] Battery assembly: Nickel-cobalt-manganese ternary positive electrode material, acetylene black, and polyvinylidene fluoride (PVDF) dissolved in N-methylpyrrolidone (NMP) were made into a slurry at a mass ratio of positive electrode material: acetylene black: PVDF = 8:1:1 and coated on aluminum foil. After drying, the aluminum foil loaded with active material was cut into small discs with a diameter of 11 mm using a cutting machine and used as the positive electrode. Metal lithium sheet was used as the negative electrode, American Celgard2300 was used as the separator, and 1M LiPF6 carbonate solution was used as the electrolyte. CR2025 button batteries were assembled in an argon glove box.

[0112] Capacity test method: The assembled CR2025 button battery was tested using a CT2001A LAND battery tester in the charge and discharge voltage range of 2.75V to 4.3V at a test temperature of 25°C.

[0113] Cyclic performance test method: After 100 charge and discharge cycles, the electrochemical performance test was performed again according to the above conditions. Industrial Applicability

[0114] The present invention introduces electric pulses during the co-precipitation process to prepare a precursor. This pulse breaks water into individual water molecules, which then wrap around the positive and negative ions with polarized water molecules, reducing the chance of collisions between the positive and negative ions. This suppresses the reaction rate during co-precipitation and reduces the use of complexing agents during the synthesis process. Under the influence of the electric pulses, the co-precipitation reaction slows down the growth rate of the crystal nuclei without the use of complexing agents, resulting in finer grains with higher sphericity. The presence of the electric pulses during the aging process also enables more uniform and dense grain growth, facilitating industrial applications.

Claims

1. A method for synthesizing a ternary precursor assisted by electric pulses, characterized in that: include: A first mixed solution containing nickel salt, cobalt salt, manganese salt and a first precipitant is placed in an electric pulse and protective atmosphere environment for a co-precipitation reaction until the precipitated particles grow to a D50 of 3μm to 5μm, and then a complexing agent and a second precipitant are added to the reaction system to obtain a second mixed solution. The second mixed solution is placed in an electric pulse environment for aging to obtain a solid-liquid mixture containing ternary precursor particles.

2. The method for synthesizing a ternary precursor by electric pulse assistance according to claim 1, characterized in that: The number of pulses of the electric pulse signal in the coprecipitation step is 5 times / s to 20 times / s, and the frequency is 3kHz to 30kHz; and / or the number of pulses of the electric pulse signal in the aging step is 5 times / s to 20 times / s, and the frequency is 3kHz to 30kHz.

3. The method for synthesizing a ternary precursor with electric pulse assistance according to claim 1 or 2, characterized in that: The coprecipitation reaction and the aging step are both carried out in a reactor, and the electric pulse generating device is installed on the outer wall of the reactor.

4. The method for synthesizing a ternary precursor with electric pulse assistance according to claim 3, characterized in that: The electric pulse generating device is installed on the outer wall at one side of the feed inlet.

5. The method for synthesizing a ternary precursor with electric pulse assistance according to claim 3 or 4, characterized in that: The electric pulse generating device is a Vulcan S100 electric pulse descaling device.

6. The method for synthesizing a ternary precursor with electric pulse assistance according to any one of claims 1 to 5, characterized in that: The nickel salt is at least one of nickel nitrate, nickel sulfate, nickel chloride, nickel oxalate and nickel acetate.

7. The method for synthesizing a ternary precursor with electric pulse assistance according to any one of claims 1 to 6, characterized in that: The cobalt salt is at least one of cobalt nitrate, cobalt sulfate, cobalt chloride, cobalt oxalate and cobalt acetate.

8. The method for synthesizing a ternary precursor with electric pulse assistance according to any one of claims 1 to 7, characterized in that: The manganese salt is at least one of manganese nitrate, manganese sulfate, manganese chloride, manganese oxalate and manganese acetate.

9. The method for synthesizing a ternary precursor with electric pulse assistance according to any one of claims 1 to 8, characterized in that: The first precipitant is at least one of sodium hydroxide, potassium hydroxide and lithium hydroxide; and / or the second precipitant is at least one of sodium hydroxide, potassium hydroxide and lithium hydroxide.

10. The method for synthesizing a ternary precursor with electric pulse assistance according to any one of claims 1 to 9, characterized in that: The total concentration of nickel ions, cobalt ions and manganese ions in the first mixed solution is 1 mol / L to 3 mol / L.

11. The method for synthesizing a ternary precursor with electric pulse assistance according to any one of claims 1 to 10, characterized in that: The protective atmosphere is at least one of nitrogen and argon.

12. The method for synthesizing a ternary precursor with electric pulse assistance according to any one of claims 1 to 11, characterized in that: The coprecipitation reaction is carried out under stirring conditions, and the stirring speed is 100r / min to 1000r / min.

13. The method for synthesizing a ternary precursor with electric pulse assistance according to any one of claims 1 to 12, characterized in that: The temperature of the coprecipitation reaction is 40° C. to 65° C., and the pH is 11 to 13.

14. The method for synthesizing a ternary precursor with electric pulse assistance according to any one of claims 1 to 13, characterized in that: The complexing agent is at least one of ammonia water, EDTA, EDTA disodium salt, citric acid, ammonium carbonate, potassium sodium tartrate and ammonium bicarbonate.

15. The method for synthesizing a ternary precursor with electric pulse assistance according to any one of claims 1 to 14, characterized in that: The content of the complexing agent in the second mixed solution is 2 g / L to 5 g / L.

16. The method for synthesizing a ternary precursor with electric pulse assistance according to any one of claims 1 to 15, characterized in that: The temperature of the aging step is 40° C. to 65° C., the pH is 9-11, and the time is 2 h to 15 h.

17. The method for synthesizing a ternary precursor with electric pulse assistance according to any one of claims 1 to 16, characterized in that: The solid-liquid mixture containing the ternary precursor particles is subjected to solid-liquid separation, and the solid phase is washed with water and dried to obtain the ternary precursor.

18. The method for synthesizing a ternary precursor with electric pulse assistance according to claim 17, characterized in that: The drying temperature is 50℃~70℃, and the drying time is 6h~24h.

19. A method for preparing a ternary material, characterized in that: The ternary material is prepared using the ternary precursor described in any one of claims 1 to 18 as a raw material.

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