High nickel ternary core-shell precursor, positive electrode material and method for producing same

Abstract

Provided is a high nickel ternary core-shell precursor for lithium batteries, a positive electrode material and a method for producing the same. The chemical structure of the precursor is zNi(C4H7N2O2)2-Ni x-z M1 y M2 1-x-y (OH)2 (wherein M1 and M2 are two of cobalt, aluminum and manganese). The prepared metal salt solution, dimethylglyoxime-ammonia water composite solution and ammonia water solution are pumped into a reaction vessel, the pH of the reaction system is maintained, the reaction time is controlled, and an approximately spherical precursor core with the structural formula of Ni(C4H7N2O2)2 is obtained. While continuing to pump the metal salt solution and ammonia water solution, the pumping of the dimethylglyoxime-ammonia water composite solution is stopped, and the sodium hydroxide solution is pumped to obtain an approximately spherical core-shell precursor. The precursor is washed, dried, sieved to remove iron, and then mixed with a lithium source and calcined to produce a positive electrode material. The material has excellent cycle properties while maintaining a high capacity.

Description

[Technical field]

[0001] The present invention relates to the technical field of lithium battery materials, in particular to a high nickel ternary core-shell precursor for lithium batteries, a positive electrode material and a method for preparing the same. [Background technology]

[0002] In recent years, with the advent of the energy crisis and the need to reduce carbon emissions, new energy vehicles have been attracting attention and occupying an increasingly large share of the market. However, in order for new energy vehicles to further develop and completely replace traditional gasoline vehicles, the problem of "range anxiety" needs to be solved. To achieve this, the power lithium battery, which is a core component of new energy vehicles, is required to have a higher energy density. To meet this requirement, it is necessary to select a positive electrode material that has a high energy density and can operate stably.

[0003] Among the currently mainstream cathode materials, lithium-rich manganese-based cathodes have a relatively low cost and high capacity, but the irreversible capacity during the first cycle is large, the voltage and capacity decay during cycling is large, and the capacity also drops rapidly at high rates, which makes it difficult to apply commercially. At present, two commercially available materials, lithium iron phosphate and ternary layered oxide materials, are mainly used as cathodes in the power battery field. Among them, lithium iron phosphate has the advantages of low cost, good cycle characteristics, and good safety, but its capacity is low, and with the improvement of the process, the specific capacity is increasingly approaching its theoretical limit, so there is limited room for future improvement, and its low temperature characteristics also limit its application range. Ternary layered oxide materials have excellent capacity density and cycle characteristics, and the higher the compressed density and the higher the Ni content, the higher the actual specific capacity, making ternary layered oxide materials more advantageous in solving the problem of "mileage anxiety". Therefore, ternary layered oxide materials are also becoming the mainstream in the power battery field in the future.

[0004] The high-nickel ternary layered oxide material has a high specific capacity. However, when the Ni content is high, the stability decreases, resulting in a decline in the cycle performance and safety of the high-nickel material, which has a significant impact on its application in the field of power batteries. Therefore, how to improve the stability of the high-nickel ternary layered oxide material has become the focus of scientific research. Currently, the core-shell structure is considered an effective means to improve stability. However, to prepare the core-shell precursor by the conventional coprecipitation method, it is necessary to change the ratio of the ternary solution, which is disadvantageous for operation. To prepare ternary solutions with different ratios, it is also necessary to increase the number of storage tanks, resulting in an increase in equipment costs.

Summary of the Invention

Problems to be Solved by the Invention

[0005] In view of the above defects existing in the prior art, the present invention provides a high-nickel ternary core-shell precursor for lithium batteries, a cathode material, and a manufacturing method thereof.

Means for Solving the Problems

[0006] The present invention is achieved by the following technical solutions.

[0007] A high-nickel ternary core-shell precursor, characterized in that its chemical structural formula is zNi(C4H7N2O2)2-Ni x-z M1 y M2 1-x-y (OH)2 (where 0.6 ≦ x ≦ 0.9, 0.05 ≦ y ≦ 0.2, 0 < z ≦ 0.24, and M1 and M2 are two of cobalt, aluminum, and manganese).

[0008] The manufacturing method of the above precursor, comprising: (1) Preparing a metal salt solution with a concentration of 2-4 mol / L at a molar ratio of soluble nickel salt, soluble metal M1 salt, and soluble metal M2 salt of Ni:M1:M2 = x:y:(1-x-y) (0.6 ≦ x ≦ 0.9, 0.05 ≦ y ≦ 0.2), and respectively preparing a dimethylglyoxime-ammonia water composite solution, a sodium hydroxide solution, and an ammonia aqueous solution; (2) Add the substrate solution to the reaction kettle, introduce N2, heat up to 40°C - 60°C, pump the metal salt solution, dimethylglyoxime-ammonia water composite solution, and aqueous ammonia solution prepared in step (1) into the reaction kettle, maintain the pH of the reaction system at 8.0 - 10.0, and react for 4 - 20 h to obtain a substantially spherical precursor core with the structural formula Ni(C4H7N2O2)2. (3) While continuously pumping the metal salt solution and aqueous ammonia solution, stop pumping the dimethylglyoxime-ammonia water composite solution, pump the sodium hydroxide solution prepared in step (1) into the reaction kettle, maintain the pH of the reaction system at 9.0 - 12.0, and continue the reaction for 30 - 80 h to obtain a substantially spherical core-shell precursor with the structural formula zNi(C4H7N2O2)2-Ni x-z M1 y M2 1-x-y (OH)2, (0.6 ≦ x ≦ 0.9, 0.05 ≦ y ≦ 0.2, 0 < z ≦ 0.24).

[0009] Furthermore, in step (1), the soluble nickel salt is one or more of nickel sulfate, nickel chloride, and nickel nitrate, and the soluble metal M1 salt and soluble metal M2 salt are two of soluble cobalt salt, soluble aluminum salt, and soluble manganese salt.

[0010] Furthermore, the soluble cobalt salt is one of cobalt sulfate, cobalt chloride, and cobalt nitrate, the soluble aluminum salt is one of aluminum sulfate, sodium metaaluminate, and aluminum nitrate, and the soluble manganese salt is one of manganese sulfate, manganese chloride, and manganese nitrate.

[0011] Furthermore, the dimethylglyoxime-ammonia water composite solution is prepared by dissolving dimethylglyoxime (C4H8N2O2) in concentrated ammonia water, the ratio of dimethylglyoxime to concentrated ammonia water is 1 g:(10 - 200 ml), the concentration of the concentrated ammonia water is 25% - 28%, and the concentrations of the sodium hydroxide solution and aqueous ammonia solution are both 2 mol / L.

[0012] Furthermore, the substrate solution in step (2) is prepared by adding water to the reaction vessel in an amount equivalent to 2 / 3 of the volume of the reaction vessel, and then adding ammonia water having a concentration of 10% to 28% to adjust the pH to 8.0 to 10.0. 3 / h.

[0013] Furthermore, in the reaction of step (2), the flow rate of the metal salt solution is 1 to 50 L / h, the flow rate of the dimethylglyoxime-ammonia water composite solution is 3 to 10 L / h, the flow rate of the ammonia water solution is 0 to 3 L / h, and the stirring speed is 200 to 400 r / min.

[0014] Furthermore, in the reaction in step (3), the flow rate of the sodium hydroxide solution is 1 to 17 L / h, and the stirring speed is 300 to 400 r / min.

[0015] A positive electrode material produced using the above precursor, The structural formula is LiNi x M1 y M2 1-x-y O2 (0.6≦x≦0.9, 0.05≦y≦0.2).

[0016] The core-shell precursor is washed, dried, and sieved to remove iron, and then mixed with a lithium source and kept at 300 to 500°C for 3 to 5 hours, and then heated to 700 to 900°C and kept at that temperature for 10 to 20 hours; The lithium source is lithium hydroxide or lithium carbonate, and the molar ratio of the lithium source to the core-shell precursor is (1-1.2:1). Effect of the Invention

[0017] The beneficial technical effects of the present invention are as follows. The present invention uses a co-precipitation method to prepare a ternary precursor with a core-shell structure, and utilizes the characteristic reaction between dimethylglyoxime and Ni ions to form a core-shell precursor with a core containing 100% nickel and a shell containing a low nickel content, without changing the chemical composition of the ternary solution. The core-shell cathode material obtained by mixing with lithium and sintering has excellent cycle characteristics while maintaining a high capacity, compared to ordinary materials with the same chemical composition. In addition, the work flow has been simplified and the number of tanks has been reduced. [Brief description of the drawings]

[0018] [Figure 1] 1 is a SEM image of the ternary precursor of Example 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] The present invention will now be described in detail with reference to the drawings and specific embodiments.

[0020] The dimethylglyoxime of the present invention can react with Ni ions in a characteristic manner, and by utilizing this reaction, a core-shell structure with 100% nickel content in the core and low nickel content in the shell can be obtained, so that the core-shell material has excellent cycle characteristics while maintaining high capacity compared with normal materials with the same chemical composition. EXAMPLES

[0021] Example 1 Step 1: Prepare a 2 mol / L metal salt solution of nickel nitrate, cobalt nitrate, and manganese nitrate in a molar ratio of Ni:Co:Mn = 0.6:0.2:0.2. Dissolve dimethylglyoxime (C4H8N2O2) in 25% to 28% concentrated aqueous ammonia to prepare a 10 g / L dimethylglyoxime-ammonia water composite solution. Prepare solutions of sodium hydroxide and aqueous ammonia with a concentration of 2 mol / L each. Step 2: Add 130 L of water (i.e., 2 / 3 of the volume of the reactor) to the reactor, adjust the pH to 8.0-9.0 using 14%-16% ammonia water, and then inject N2 into the reactor at a flow rate of 0.6 m 3 / h, the temperature was raised to 50°C, and the above metal salt solution was pumped into the reaction kettle at 8 L / h, dimethylglyoxime-ammonia water composite solution at 10 L / h, and ammonia water solution at 0-3 L / h. The pH during the reaction was maintained at 8.0-9.0 and the stirring speed at 340-380 r / min, and the reaction was carried out for 10 hours to obtain approximately spherical precursor cores with the structural formula Ni(C4H7N2O2)2. Step 3: While continuing to pump the metal salt solution and ammonia water solution, stop pumping the dimethylglyoxime-ammonia water composite solution, pump 2mol / L sodium hydroxide solution into the reaction kettle at 1.4-1.6L / h, maintain the pH during the reaction at 9.4-10.0, and the stirring speed at 340-380r / min, and continue the reaction for 60h. The structural formula is 0.1Ni(C4H7N2O2)2-Ni 0.5 Co 0.2 Mn 0.2 A roughly spherical core-shell precursor of (OH)2 was obtained. Step 4: The above core-shell precursor is washed, dried, sieved to remove iron, and then mixed with lithium carbonate. The mixture is heated at 400°C for 5 hours, then heated to 800°C and heated for 12 hours to obtain a compound with the structural formula LiNi 0.6 Co 0.2 Mn 0.2 A ternary material with a core-shell structure of O2 was obtained. The molar ratio of lithium carbonate to the precursor was 1.2:1. The positive electrode material was assembled into a CR2025 button battery, and the electrochemical properties of the battery were detected. At a rate of 0.1C and a voltage range of 2.8 to 4.3V, the discharge capacity was 182.1mA / g, and the capacity retention rate after 100 cycles at 0.5C was 92.9%.

[0022] Example 2 Step 1: Prepare a 2 mol / L metal salt solution of nickel chloride, cobalt chloride, and manganese chloride in a molar ratio of Ni:Co:Mn = 0.8:0.1:0.1. Dissolve dimethylglyoxime (C4H8N2O2) in 25% to 28% concentrated aqueous ammonia to prepare a 10 g / L dimethylglyoxime-ammonia water composite solution. Prepare solutions of sodium hydroxide and aqueous ammonia with a concentration of 2 mol / L each. Step 2: Add 130 L of water to the reactor, adjust the pH to 8.0-9.0 with 14%-16% ammonia water, and inject N2 into the reactor at a flow rate of 0.6 m 3 / h, the temperature was raised to 50°C, and the above metal salt solution was pumped into the reaction kettle at 8 L / h, dimethylglyoxime-ammonia water composite solution at 10 L / h, and ammonia water solution at 0-3 L / h. The pH during the reaction was maintained at 8.0-9.0 and the stirring speed at 340-380 r / min, and the reaction was carried out for 10 hours to obtain approximately spherical precursor cores with the structural formula Ni(C4H7N2O2)2. Step 3: While continuing to pump the metal salt solution and ammonia water solution, stop pumping the dimethylglyoxime-ammonia water composite solution, pump 2mol / L sodium hydroxide solution into the reaction kettle at 1.4-1.6L / h, maintain the pH during the reaction at 9.6-11.0, and the stirring speed at 340-380r / min. Continue the reaction for 55h, and the structural formula is 0.1Ni(C4H7N2O2)2-Ni 0.7 Co 0.1 Mn 0.1 A roughly spherical core-shell precursor of (OH)2 was obtained. Step 4: The above core-shell precursor is washed, dried, sieved to remove iron, and then mixed with lithium hydroxide and heated at 400°C for 5 hours, then heated to 800°C and heated for 12 hours to obtain a compound with the structural formula LiNi 0.8 Co 0.1 Mn 0.1 A ternary material with a core-shell structure of O2 was obtained. The molar ratio of lithium hydroxide to the precursor was 1.2:1. The positive electrode material was assembled into a CR2025 button battery, and the electrochemical properties of the battery were detected. At a rate of 0.1C and a voltage range of 2.8 to 4.3V, the discharge capacity was 191.4mA / g, and the capacity retention rate after 100 cycles at 0.5C was 92.3%.

[0023] Example 3 Step 1: Prepare a 2 mol / L metal salt solution of nickel sulfate, cobalt sulfate, and manganese sulfate in a molar ratio of Ni:Co:Mn = 0.9:0.05:0.05. Dissolve dimethylglyoxime (C4H8N2O2) in 25% to 28% concentrated ammonia water to prepare a 10 g / L dimethylglyoxime-ammonia water composite solution. Prepare solutions of sodium hydroxide and ammonia water with a concentration of 2 mol / L each. Step 2: Add 130 L of water to the reactor, adjust the pH to 8.0-9.0 with 14%-16% ammonia water, and inject N2 into the reactor at a flow rate of 0.6 m 3 / h, the temperature was raised to 50°C, and the above metal salt solution was pumped into the reaction kettle at 8 L / h, dimethylglyoxime-ammonia water composite solution at 10 L / h, and ammonia water solution at 0-3 L / h. The pH during the reaction was maintained at 8.0-9.0 and the stirring speed at 340-380 r / min, and the reaction was carried out for 10 hours to obtain approximately spherical precursor cores with the structural formula Ni(C4H7N2O2)2. Step 3: While continuing to pump the metal salt solution and ammonia water solution, stop pumping the dimethylglyoxime-ammonia water composite solution, pump 2mol / L sodium hydroxide solution into the reaction kettle at 1.4-1.6L / h, maintain the pH during the reaction at 11.0-12.0, and the stirring speed at 340-380r / min, and continue the reaction for 50h. The structural formula is 0.1Ni(C4H7N2O2)2-Ni 0.8 Co 0.05 Mn 0.05 A roughly spherical core-shell precursor of (OH)2 was obtained. Step 4: The above core-shell precursor is washed, dried, sieved to remove iron, and then mixed with lithium hydroxide and heated at 400°C for 5h, then heated to 800°C and heated for 12h to obtain a core-shell structured ternary material with the structural formula LiNi0.9Co0.05Mn0.05O2. The molar ratio of lithium hydroxide to precursor is 1.2:1. The positive electrode material is assembled into a CR2025 button battery, and the electrochemical properties of the battery are detected. At a rate of 0.1C and a voltage range of 2.8-4.3V, the discharge capacity is 217.1mA / g, and the capacity retention rate after 100 cycles at 0.5C is 90.3%.

[0024] Example 4 Step 1: Prepare a 3 mol / L metal salt solution of nickel sulfate, cobalt sulfate, and sodium metaaluminate in a molar ratio of Ni:Co:Al = 0.8:0.15:0.05. Dissolve dimethylglyoxime (C4H8N2O2) in 25% to 28% concentrated aqueous ammonia to prepare a 10 g / L dimethylglyoxime-ammonia water composite solution. Prepare solutions of sodium hydroxide and aqueous ammonia with a concentration of 2 mol / L each. Step 2: Add 130 L of water to the reactor, adjust the pH to 8.0-9.0 with 14%-16% ammonia water, and inject N2 into the reactor at a flow rate of 0.6 m 3 / h, the temperature was raised to 58°C, and the above metal salt solution was pumped into the reaction kettle at 30 L / h, dimethylglyoxime-ammonia water composite solution at 5 L / h, and ammonia water solution at 0-3 L / h. The pH during the reaction was maintained at 9.0-10.0 and the stirring speed at 340-360 r / min, and the reaction was carried out for 20 hours to obtain approximately spherical precursor cores with the structural formula Ni(C4H7N2O2)2. Step 3: While continuing to pump the metal salt solution and ammonia water solution, stop pumping the dimethylglyoxime-ammonia water composite solution, pump 8-10L / h of 2mol / L sodium hydroxide solution into the reaction kettle, maintain the pH during the reaction at 9.2-9.8, and the stirring speed at 380-400r / min. Continue the reaction for 70h, and the structural formula is 0.2Ni(C4H7N2O2)2-Ni 0.6 Co 0.15 Al 0.05 A roughly spherical core-shell precursor of (OH)2 was obtained. Step 4: The above core-shell precursor is washed, dried, and sieved to remove iron, then mixed with lithium carbonate and heated at 500°C for 3 hours, then heated to 900°C and heated for 11 hours to obtain a compound with the structural formula LiNi 0.8 Co 0.15 Al 0.05A ternary material with a core-shell structure of O2 was obtained. The molar ratio of lithium carbonate to the precursor was 1.1:1. The positive electrode material was assembled into a CR2025 button battery, and the electrochemical properties of the battery were detected. At a rate of 0.1C and a voltage range of 2.8 to 4.3V, the discharge capacity was 190.3mA / g, and the capacity retention rate after 100 cycles at 0.5C was 90.2%.

[0025] Example 5 Step 1: Prepare a 4 mol / L metal salt solution of nickel sulfate, cobalt sulfate, and aluminum nitrate in a molar ratio of Ni:Co:Al = 0.89:0.1:0.01. Dissolve dimethylglyoxime (C4H8N2O2) in 25% to 28% concentrated aqueous ammonia to prepare a 10 g / L dimethylglyoxime-ammonia water composite solution. Prepare solutions of sodium hydroxide and aqueous ammonia with a concentration of 2 mol / L each. Step 2: Add 130 L of water to the reactor, adjust the pH to 8.0-9.0 with 14%-16% ammonia water, and inject N2 into the reactor at a flow rate of 1.5 m 3 / h, the temperature was raised to 58°C, and the above metal salt solution was pumped into the reaction kettle at 45 L / h, dimethylglyoxime-ammonia water composite solution at 5 L / h, and ammonia water solution at 0-2 L / h. The pH during the reaction was maintained at 8.0-9.0 and the stirring speed at 340-360 r / min. The reaction was carried out for 20 hours, and approximately spherical precursor cores with the structural formula Ni(C4H7N2O2)2 were obtained. Step 3: While continuing to pump the metal salt solution and ammonia water solution, stop pumping the dimethylglyoxime-ammonia water composite solution, pump 15-17L / h of 2mol / L sodium hydroxide solution into the reaction kettle, maintain the pH during the reaction at 10.0-11.4, and the stirring speed at 300-320r / min. The reaction continues for 65h, and the structural formula is 0.24Ni(C4H7N2O2)2-Ni 0.65 Co 0.1 Al 0.01 A roughly spherical core-shell precursor of (OH)2 was obtained. Step 4: The above core-shell precursor is washed, dried, sieved to remove iron, and then mixed with lithium hydroxide and heated at 300°C for 4 hours, then heated to 850°C and heated for 10 hours to obtain a compound with the structural formula LiNi0.89 Co 0.1 Al 0.01 A ternary material with a core-shell structure of O2 was obtained. The molar ratio of lithium hydroxide to the precursor was 1.2:1. The positive electrode material was assembled into a CR2025 button battery, and the electrochemical properties of the battery were detected. At a rate of 0.1C and a voltage range of 2.8 to 4.3V, the discharge capacity was 210.4mA / g, and the capacity retention rate after 100 cycles at 0.5C was 91.4%.

[0026] Example 6 Step 1: Prepare a 2 mol / L metal salt solution of nickel sulfate, manganese sulfate, and aluminum sulfate in a molar ratio of Ni:Mn:Al = 0.9:0.05:0.05. Dissolve dimethylglyoxime (C4H8N2O2) in 25% to 28% concentrated ammonia water to prepare a 10 g / L dimethylglyoxime-ammonia water composite solution. Prepare solutions of sodium hydroxide and ammonia water with a concentration of 2 mol / L each. Step 2: Add 130 L of water to the reactor, adjust the pH to 8.0-9.0 with 14%-16% ammonia water, and inject N2 into the reactor at a flow rate of 0.6 m 3 / h, the temperature was raised to 58°C, and the above metal salt solution was pumped into the reaction kettle at 40 L / h, dimethylglyoxime-ammonia water composite solution at 8 L / h, and ammonia water solution at 2-3 L / h. The pH during the reaction was maintained at 8.0-9.0 and the stirring speed at 340-360 r / min, and the reaction was carried out for 10 hours to obtain approximately spherical precursor cores with the structural formula Ni(C4H7N2O2)2. Step 3: While continuing to pump the metal salt solution and ammonia water solution, stop pumping the dimethylglyoxime-ammonia water composite solution, pump 13-15L / h of 2mol / L sodium hydroxide solution into the reaction kettle, maintain the pH during the reaction at 11.0-12.0, and the stirring speed at 360-380r / min. The reaction continues for 50h, and the structural formula is 0.1Ni(C4H7N2O2)2-Ni 0.8 Mn 0.05 Al 0.05 A roughly spherical core-shell precursor of (OH)2 was obtained. Step 4: The above core-shell precursor is washed, dried, sieved to remove iron, and then mixed with lithium hydroxide and heated at 400°C for 5 hours, then heated to 800°C and heated for 12 hours to obtain a compound with the structural formula LiNi 0.9 Mn 0.05 Al 0.05 A ternary material with a core-shell structure of O2 was obtained. The molar ratio of lithium hydroxide to the precursor was 1.2:1. The positive electrode material was assembled into a CR2025 button battery, and the electrochemical properties of the battery were detected. At a rate of 0.1C and a voltage range of 2.8 to 4.3V, the discharge capacity was 209.7mA / g, and the capacity retention rate after 100 cycles at 0.5C was 90.1%.

[0027] The above are only preferred embodiments of the present invention, and are not intended to be limiting. Those skilled in the art can make other equivalent modifications under the technical suggestions provided by the present invention, and all of these modifications can achieve the objectives of the present invention and are considered to be within the protection scope of the present invention.

Claims

1. (1) preparing a 2-4 mol / L metal salt solution of a soluble nickel salt, a soluble metal M1 salt, and a soluble metal M2 salt in a molar ratio of Ni:M1:M2=x:y:(1-x-y) (0.6≦x≦0.9, 0.05≦y≦0.2), and preparing a dimethylglyoxime-ammonia water composite solution, a sodium hydroxide solution, and an ammonia water solution; (2) Add the substrate solution to the reaction vessel and 2 The metal salt solution prepared in step (1), the dimethylglyoxime-ammonia water composite solution, and the ammonia water solution are pumped into the reactor, and the pH of the reaction system is maintained at 8.0-10.

0. The reaction is carried out for 4-20 hours, and the structural formula of the metal salt solution is Ni(C 4 H 7 N 2 O 2 ) 2 obtaining a substantially spherical precursor core of (3) While continuing to pump the metal salt solution and the aqueous ammonia solution, stop pumping the dimethylglyoxime-ammonia aqueous solution, and pump the sodium hydroxide solution prepared in step (1) into the reaction kettle. The pH of the reaction system is maintained at 9.0-12.

0. The reaction is continued for 30-80 h, and the structural formula is zNi(C 4 H 7 N 2 O 2 ) 2 -Ni x-z M1 y M2 1-x-y (OH) 2 , (0.6≦x≦0.9, 0.05≦y≦0.2, 0<z≦0.24) to obtain a substantially spherical core-shell precursor; A method for producing a high nickel ternary core-shell precursor having a chemical structural formula of zNi(C4H7N2O2)2-Ni xzM1yM21-xy(OH)2, where 0.6≦x≦0.9, 0.05≦y≦0.2, 0<z≦0.24, and M1 and M2 are two of cobalt, aluminum, and manganese, comprising:

2. 2. The method according to claim 1, wherein in step (1), the soluble nickel salt is one or more of nickel sulfate, nickel chloride, and nickel nitrate, and the soluble metal M1 salt and the soluble metal M2 salt are two of a soluble cobalt salt, a soluble aluminum salt, and a soluble manganese salt.

3. 3. The method according to claim 2, wherein the soluble cobalt salt is one of cobalt sulfate, cobalt chloride, and cobalt nitrate, the soluble aluminum salt is one of aluminum sulfate, sodium metaaluminate, and aluminum nitrate, and the soluble manganese salt is one of manganese sulfate, manganese chloride, and manganese nitrate.

4. The dimethylglyoxime-ammonia water composite solution contains dimethylglyoxime (C 4 H 8 N 2 O 2 2. The method according to claim 1, wherein the dimethylglyoxime is dissolved in concentrated aqueous ammonia, the ratio of dimethylglyoxime to concentrated aqueous ammonia is 1 g:(10 to 200 ml), the concentration of the concentrated aqueous ammonia is 25% to 28%, and the concentrations of the sodium hydroxide solution and the aqueous ammonia solution are all 2 mol / L.

5. The substrate solution in step (2) is prepared by adding water to the reaction vessel in an amount equivalent to 2 / 3 of the volume of the reaction vessel, and then adding ammonia water having a concentration of 10% to 28% to adjust the pH to 8.0 to 10.

0. 2 Flow rate is 0.5 to 2 m 3 2. The method according to claim 1, wherein the reaction is carried out at a temperature of 1000° C. / h.

6. 2. The method according to claim 1, wherein in the reaction of step (2), the flow rate of the metal salt solution is 1 to 50 L / h, the flow rate of the dimethylglyoxime-ammonia water composite solution is 3 to 10 L / h, the flow rate of the ammonia water solution is 0 to 3 L / h, and the stirring speed is 200 to 400 r / min.

7. The method according to claim 1, characterized in that in the reaction of step (3), the flow rate of the sodium hydroxide solution is 1 to 17 L / h, and the stirring speed is 300 to 400 r / min.

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