Method for synthesizing ternary positive electrode material precursor of lithium ion battery by using solid-state method

Abstract

The invention discloses a method for synthesizing a ternary positive electrode material precursor of a lithium ion battery by using a solid-state method, which is characterized by comprising the following steps: (1) taking a solid-state metal salt and a solid-state alkali, adding the solid-state metal salt and the solid-state alkali into mixing equipment at the temperature of 0-550 DEG C, and inducing the solid-state metal salt and the solid-state alkali to generate a solid-state reaction under continuous stirring to obtain a precipitate; the mass ratio of the solid alkali to the solid metal salt is (1: 1)-(10: 1), and the mixing time is 5 minutes to 100 hours; (2) transferring the precipitate obtained in the step (1) into a heating furnace, and carrying out heat treatment at the temperature of 30-900 DEG C to obtain an initial precursor for 5-100 hours; and (3) washing the initial precursor obtained in the step (2) with deionized water, filtering and drying to obtain the ternary positive electrode material precursor of the lithium ion battery. The technical problems that a traditional liquid coprecipitation method is complex in operation and high in control requirement, and a transition metal oxide solid synthesis route is high in cost and poor in material uniformity are solved.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and specifically to a method for synthesizing ternary cathode material precursors for lithium-ion batteries using a solid-state method. Background Technology

[0002] The synthesis of ternary cathode materials for lithium-ion batteries generally involves a two-step process: first, a hydroxide or carbonate precursor is synthesized using a solution of transition metal sulfates such as nickel, cobalt, and manganese, a sodium hydroxide precipitant, and an ammonia complexing agent; then, a lithium source is introduced, followed by a high-temperature solid-state method. While transition metal sulfate precursors are inexpensive, the process of synthesizing ternary precursors via liquid co-precipitation is complex, requiring strict control of the feed rates of the metal salt solution, precipitant, and complexing agent, as well as the stirrer speed, precipitation pH, and reaction temperature. For example, patents CN202310002191.4 and CN201711242826.9 use a nickel, cobalt, and manganese sulfate solution, sodium hydroxide precipitant, and ammonia complexing agent as precursors to synthesize a high-nickel Ni0.83Co0.06Mn0.11(OH)2 precursor via liquid precipitation. Precise control of solution concentration, reaction temperature, pH, and particle size is required during the precipitation process. Patents CN202011502737.5 and CN201910289498.0 employ transition metal oxides and lithium sources, ball-milling the mixture followed by high-temperature calcination to synthesize single-crystal high-nickel ternary cathode materials. While this method offers the advantage of a simple synthesis process, the cost of oxide precursors is significantly higher than that of sulfate precursors, and the uniformity of the resulting ternary cathode material is inferior to that of the co-precipitation method. Therefore, the solid-state synthesis route using transition metal oxides has not seen widespread application. Given the current high cost pressures associated with high-nickel ternary cathode materials, it is necessary to develop a method for preparing lithium-ion battery ternary cathode material precursors that offers lower cost, simpler operation, and superior performance compared to traditional liquid precipitation methods. Summary of the Invention

[0003] This invention provides a method for synthesizing ternary cathode material precursors for lithium-ion batteries using a solid-state method, which solves the technical problems of complex operation and high control requirements of traditional liquid co-precipitation method, as well as high cost and poor material uniformity of solid-state synthesis route of transition metal oxides.

[0004] To address the aforementioned technical problems, this invention provides a method for synthesizing ternary cathode material precursors for lithium-ion batteries using a solid-state method, characterized by comprising the following steps: (1) Take solid metal salt and solid alkali, add them to a mixing device at a temperature of 0-550℃, and induce them to undergo a solid reaction under continuous stirring to obtain a precipitate; The molar ratio of the solid alkali to the solid metal salt is 1:1 to 10:1, and the mixing time is 5 min to 100 h. (2) The precipitate obtained in step (1) is transferred to a heating furnace and heat-treated at a temperature of 30℃-900℃ to obtain the initial precursor. The heat treatment time is 5min-100h. (3) Take the initial precursor obtained in step (2), wash, filter and dry it with deionized water to obtain the ternary cathode material precursor for lithium-ion batteries.

[0005] Further, the mixing equipment in step (1) is a stirring tank, a mixer, a pulverizer, a ball mill, or a sand mill.

[0006] Furthermore, the solid metal salt in step (1) is mainly composed of metal elements Ni, Co, Mn or Al; Solid alkalis are sodium hydroxide, sodium carbonate, sodium bicarbonate, ammonium carbonate, urea, oxalic acid, potassium carbonate, potassium hydroxide, disodium ethylenediaminetetraacetate, or mixtures thereof.

[0007] Furthermore, if the temperatures in steps (1) and (2) are the same, they can be combined.

[0008] Furthermore, during the mixing process in step (1), the solid alkali can be added to the solid metal salt, the solid metal salt can be added to the solid alkali, or both can be added to the mixing device together.

[0009] Furthermore, during the mixing process in step (1), heating conditions are provided to better promote the solid precipitation reaction.

[0010] Furthermore, in the mixing process of step (2), a nitrogen atmosphere is introduced to eliminate the interference of oxygen.

[0011] The beneficial effects of this invention are: 1. Simpler process operation: There is no need to strictly control parameters such as solution concentration, feed rate, and pH value. It can be completed simply through solid mixing, heat treatment and post-treatment, which simplifies the production process.

[0012] 2. Lower cost: Using inexpensive solid metal salts (with Ni, Co, Mn or Al as the main components) as raw materials avoids the use of high-valence oxide precursors. In addition, the preferred solid alkalis such as sodium hydroxide, sodium carbonate, and sodium bicarbonate have lower costs, while reducing equipment investment and energy consumption.

[0013] 3. Excellent material properties: By controlling the mixing equipment, mixing process and heat treatment parameters, the specific capacity and cycle stability of the ternary cathode material can be optimized; the prepared precursor has a spherical structure, the product is free of sulfate impurities, and its performance is comparable to that of the traditional liquid coprecipitation method.

[0014] 4. Wide applicability: It is suitable for synthesizing precursors of nickel-cobalt-manganese ternary cathode materials and nickel-cobalt-aluminum ternary cathode materials, and can also be used to synthesize precursors of high-nickel and medium-nickel ternary cathode materials.

[0015] 5. Environmentally friendly: The use of solid alkalis such as sodium hydroxide, sodium carbonate, and sodium bicarbonate avoids the problems of nitrogen oxides or ammonia produced by the high-temperature decomposition of ammonium carbonate and urea, as well as the production of organic gases or carbon monoxide and other toxic gases by oxalic acid at high temperatures, thus reducing the investment cost of environmental protection equipment. Attached Figure Description

[0016] Figure 1 This is a SEM image of C-1, the precursor of the ternary cathode material for lithium-ion batteries of the present invention.

[0017] Figure 2 This is a SEM image of CC-6, the ternary cathode material for lithium-ion batteries of the present invention.

[0018] Figure 3 This is a table showing the electrochemical performance test results of the ternary cathode material for lithium-ion batteries of the present invention. Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0020] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0021] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0022] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0023] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0024] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0025] Reference Figures 1 to 3 As shown, an embodiment of the method for synthesizing a ternary cathode material precursor for lithium-ion batteries using a solid-state method according to the present invention includes the following steps: (1) Take solid metal salt and solid alkali, add them to a mixing device at a temperature of 0-550℃, and induce them to undergo a solid reaction under continuous stirring to obtain a precipitate; The molar ratio of the solid alkali to the solid metal salt is 1:1 to 10:1, and the mixing time is 5 min to 100 h. (2) The precipitate obtained in step (1) is transferred to a heating furnace and heat-treated at a temperature of 30℃-900℃ to obtain the initial precursor. The heat treatment time is 5min-100h. (3) Take the initial precursor obtained in step (2), wash, filter and dry it with deionized water to obtain the ternary cathode material precursor for lithium-ion batteries.

[0026] In step (1), the mixing equipment is a stirred tank, mixer, pulverizer, ball mill, or sand mill. The solid metal salt is mainly composed of the metal elements Ni, Co, Mn, or Al. The solid alkali is sodium hydroxide, sodium carbonate, sodium bicarbonate, ammonium carbonate, urea, oxalic acid, potassium carbonate, potassium hydroxide, disodium ethylenediaminetetraacetate, or a mixture thereof, preferably sodium hydroxide, sodium carbonate, sodium bicarbonate, or combinations thereof. Ammonium carbonate, urea, and oxalic acid are prone to decomposition at high temperatures, and their tendency to precipitate with metal salts via solid-state methods is weaker, which may lead to incomplete solid-state precipitation. In addition, from an environmental perspective, ammonium carbonate and urea contain nitrogen, which will produce nitrogen oxides or ammonia during high-temperature calcination, increasing the investment cost of environmental protection equipment. Oxalic acid contains organic groups, which will produce organic gases or toxic gases such as carbon monoxide during high-temperature calcination. Potassium hydroxide, potassium carbonate, and disodium ethylenediaminetetraacetate are expensive, resulting in high material preparation costs, which is not conducive to large-scale industrial applications.

[0027] If the temperatures in steps (1) and (2) are the same, they can be combined. When mixing in step (1), the solid alkali can be added to the solid metal salt, the solid metal salt can be added to the solid alkali, or both can be added to the mixing device together.

[0028] In the mixing process of step (1), heating conditions are provided to better promote the solid precipitation reaction. In the mixing process of step (2), a nitrogen atmosphere is introduced to eliminate the interference of oxygen.

[0029] The following are specific embodiments and experimental methods: Example 1: (1) Weigh solid metal salts nickel sulfate monohydrate, cobalt sulfate heptahydrate, and manganese sulfate monohydrate, and place them in a stirred tank, wherein the molar ratio of Ni, Co, and Mn is 0.9:0.05:0.05. Turn on the stirrer, heat the stirred tank to 50°C, and stir at 100 rpm for 1 h to obtain a mixed metal salt. Weigh solid sodium carbonate and add it to the stirred tank, wherein the molar ratio of Na:(Ni+Co+Mn) is 5. Heat the stirred tank to 100°C and continue stirring for 10 h to obtain a precipitate. (2) Transfer the precipitate to a calcining furnace and calcine it at 550°C for 10 h in an air atmosphere to obtain the initial precursor. (3) Take the initial precursor, filter it, wash it with deionized water to obtain a filter cake, and place the filter cake in an oven at 120°C for 10 h to obtain the ternary cathode material precursor C1.

[0030] Example 2: (1) Weigh solid metal salts nickel sulfate monohydrate, cobalt sulfate heptahydrate, and manganese sulfate monohydrate, and place them in a VC mixer, wherein the molar ratio of Ni, Co, and Mn is 0.9:0.05:0.05. Turn on the VC mixer and stir at 200 rpm for 1 h to obtain a mixed metal salt. Weigh solid sodium hydroxide and add it to the above VC mixer, wherein the molar ratio of Na:(Ni+Co+Mn) is 3, and continue stirring for 2 h to obtain a precipitate. (2) Transfer the precipitate to a kiln and calcine it at 350℃ for 10 h in an oxygen atmosphere to obtain the initial precursor. (3) Take the initial precursor, filter it by pressure, wash it with deionized water to obtain a filter cake, and place the filter cake in an oven at 100℃ for 10 h to obtain the ternary cathode material precursor C2.

[0031] Example 3: (1) Weigh solid metal salts nickel sulfate monohydrate, cobalt sulfate heptahydrate, and manganese sulfate monohydrate, and solid alkaline potassium hydroxide, and place them in a VC mixer. The molar ratio of Ni, Co, and Mn is 0.9:0.05:0.05, and the molar ratio of Na:(Ni+Co+Mn) is 2. Turn on the VC mixer and stir at 300 rpm for 1 h to obtain a precipitate. (2) Transfer the precipitate to a stirred tank and heat-treat it at 100℃ for 60 h in a nitrogen atmosphere to obtain the initial precursor. (3) Take the initial precursor, filter it, wash it with deionized water to obtain a filter cake, and place the filter cake in an oven at 100℃ for 10 h to obtain the ternary cathode material precursor C3.

[0032] Example 4: (1) Weigh solid metal salts nickel sulfate monohydrate, cobalt sulfate heptahydrate, and manganese sulfate monohydrate, and place them in a pulverizer, wherein the molar ratio of Ni, Co, and Mn is 0.9:0.05:0.05. Turn on the pulverizer and stir at 300 rpm for 1 hour to obtain a mixed metal salt. Weigh solid potassium carbonate and add it to the pulverizer, wherein the molar ratio of Na:(Ni+Co+Mn) is 3, and continue pulverizing for 2 hours to obtain a precipitate. (2) Transfer the precipitate to a calcining furnace and calcine it at 750℃ for 5 hours in an oxygen atmosphere to obtain the initial precursor. (3) Take the initial precursor, filter it by pressure, wash it with deionized water to obtain a filter cake, and place the filter cake in an oven at 120℃ for 10 hours to obtain the ternary cathode material precursor C4.

[0033] Example 5: (1) Weigh solid metal salts nickel sulfate monohydrate, cobalt sulfate heptahydrate, and manganese sulfate monohydrate, and place them in a grinder, wherein the molar ratio of Ni, Co, and Mn is 0.9:0.05:0.05. Turn on the grinder and stir at 400 rpm for 1 hour to obtain a mixed metal salt. Weigh solid sodium carbonate / sodium hydroxide = 2 / 1 (mass ratio) and add it to the above grinder, wherein the molar ratio of Na:(Ni+Co+Mn) is 4. Continue grinding for 1 hour to obtain a precipitate. (2) Transfer the precipitate to a calcining furnace and calcine it at 550℃ for 10 hours in an oxygen atmosphere to obtain the initial precursor. (3) Take the initial precursor, filter it, wash it with deionized water to obtain a filter cake, and place the filter cake in an oven at 120℃ for 10 hours to obtain the ternary cathode material precursor C5.

[0034] Example 6: (1) Weigh solid metal salts nickel sulfate monohydrate, cobalt sulfate heptahydrate, and anhydrous aluminum sulfate, and place them in a stirred tank, wherein the molar ratio of Ni, Co, and Al is 0.9:0.05:0.05. Turn on the stirrer, heat the stirred tank to 50°C, and stir at 100 rpm for 1 h to obtain a mixed metal salt. Weigh solid sodium carbonate and add it to the stirred tank, wherein the molar ratio of Na:(Ni+Co+Al) is 2. Heat the stirred tank to 100°C and continue stirring for 5 h to obtain a precipitate. (2) Transfer the precipitate to a calcining furnace and calcine it at 550°C for 5 h in an air atmosphere to obtain the initial precursor. (3) Take the initial precursor, filter it, wash it with deionized water to obtain a filter cake, and place the filter cake in an oven at 120°C for 10 h to obtain the ternary cathode material precursor C6.

[0035] Example 7: (1) Weigh solid metal salts nickel sulfate monohydrate, cobalt sulfate heptahydrate, and manganese sulfate monohydrate, and place them in a stirred tank, wherein the molar ratio of Ni, Co, and Mn is 0.8:0.1:0.1. Turn on the stirrer, heat the stirred tank to 75°C, and stir at 100 rpm for 1 h to obtain a mixed metal salt. Weigh solid sodium carbonate and add it to the stirred tank, wherein the molar ratio of Na:(Ni+Co+Mn) is 5. Heat the stirred tank to 75°C and continue stirring for 10 h to obtain a precipitate. (2) Transfer the precipitate to a calcining furnace and calcine it at 550°C for 5 h in an air atmosphere to obtain the initial precursor. (3) Take the initial precursor, filter it by pressure, wash it with deionized water to obtain a filter cake, and place the filter cake in an oven at 120°C for 10 h to obtain the ternary cathode material precursor C7.

[0036] Example 8: (1) Weigh solid metal salts nickel sulfate monohydrate, cobalt sulfate heptahydrate, and manganese sulfate monohydrate, and place them in a stirred tank, wherein the molar ratio of Ni, Co, and Mn is 0.6:0.2:0.2. Turn on the stirrer, heat the stirred tank to 75°C, and stir at 100 rpm for 1 h to obtain a mixed metal salt. Weigh solid sodium carbonate and add it to the stirred tank, wherein the molar ratio of Na:(Ni+Co+Mn) is 5. Heat the stirred tank to 75°C and continue stirring for 10 h to obtain a precipitate. (2) Transfer the precipitate to a calcining furnace and calcine it at 550°C for 5 h in an air atmosphere to obtain the initial precursor. (3) Take the initial precursor, filter it, wash it with deionized water to obtain a filter cake, and place the filter cake in an oven at 120°C for 10 h to obtain the ternary cathode material precursor C8.

[0037] Example 9: (1) Weigh solid metal salts nickel sulfate monohydrate, cobalt sulfate heptahydrate, and manganese sulfate monohydrate, and place them in a stirred tank, wherein the molar ratio of Ni, Co, and Mn is 0.5:0.1:0.1. Turn on the stirrer, heat the stirred tank to 75°C, and stir at 100 rpm for 1 h to obtain a mixed metal salt. Weigh solid sodium carbonate and add it to the stirred tank, wherein the molar ratio of Na:(Ni+Co+Mn) is 5. Heat the stirred tank to 75°C and continue stirring for 10 h to obtain a precipitate. (2) Transfer the precipitate to a calcining furnace and calcine it at 550°C for 5 h in an air atmosphere to obtain the initial precursor. (3) Take the initial precursor, filter it, wash it with deionized water to obtain a filter cake, and place the filter cake in an oven at 120°C for 10 h to obtain the ternary cathode material precursor C9.

[0038] Reference Example 1: The preparation method of the precursor is basically the same as that of Example 1, except that the molar ratio of Li:(Ni+Fe+Mn) is changed to 1:1 to obtain the ternary cathode material precursor CC-1.

[0039] Reference Example 2: The preparation method of the precursor is basically the same as that of Example 1, except that step (2) is removed, and the ternary cathode material precursor CC2 is obtained.

[0040] Reference Example 3: The preparation method of the precursor is basically the same as that of Example 1, except that the solid alkali is replaced with urea to obtain the ternary cathode material precursor CC-3.

[0041] Reference Example 4: The preparation method of the precursor is basically the same as that of Example 1, except that the solid alkali is replaced with ammonium carbonate to obtain the ternary cathode material precursor CC-4.

[0042] Reference Example 5: The preparation method of the precursor is basically the same as that of Example 1, except that the solid alkali is replaced with oxalic acid to obtain the ternary cathode material precursor CC-5.

[0043] Reference Example 6: Preparation of ternary cathode material precursor for lithium-ion batteries by liquid co-precipitation method. (1) Weigh nickel sulfate monohydrate, cobalt sulfate heptahydrate and manganese sulfate monohydrate (molar ratio of Ni, Co and Mn is 0.9:0.05:0.05), add deionized water to prepare salt solution. Prepare alkaline solution with sodium hydroxide and deionized water. Prepare complexing agent solution with ammonia and deionized water. (2) Add salt solution, alkaline solution and complexing agent solution to reactor in parallel. Nitrogen gas is continuously introduced into reactor for protection. The reactor temperature is controlled at 50℃. The pH is controlled at 11.0-12.0 during precipitation. After the reaction is completed, continue stirring for 20h to obtain precipitate. (3) Filter the precipitate by pressure, wash with deionized water to obtain filter cake. Place the filter cake in a 120℃ oven to dry for 10h to obtain ternary cathode material precursor CC-6.

[0044] Preparation of ternary cathode materials for lithium-ion batteries Precursors C-1 to C-9 and CC-1 to CC-6 from Examples 1-12 and Reference Examples 1-6 were respectively mixed with lithium hydroxide and nano-zirconia, wherein the Li / M (M represents all metals in the precursor) molar ratio was 1.04 and the Zr / M molar ratio was 0.01. The mixture was pulverized and mixed to obtain a mixture. The mixture was calcined at 550°C for 10 hours in an oxygen atmosphere to obtain a ternary cathode material matrix. The obtained matrix was washed with water, dried at 120°C for 10 hours, and nano-niobium oxide (Nb / M molar ratio of 0.005) was added. The mixture was pulverized and mixed evenly, and then calcined at 750°C for 10 hours in an oxygen atmosphere to obtain a high-nickel ternary cathode material, with material numbers LiC-1 to LiC-12 and LiCC-1 to LiCC-6 respectively.

[0045] Battery assembly and testing The ternary cathode material synthesized in Examples 1-9 and Reference Examples 1-6, conductive carbon black, PVDF, and NMP were mixed in a mass ratio of 94:3:3:100, stirred for 5 hours, coated onto aluminum foil, and dried in a vacuum drying oven at 105°C for 12 hours. The mixture was then cut into Φ12mm electrode sheets, which were used as the positive electrode. A lithium metal sheet was used as the negative electrode. The electrolyte was 1M LiPF6+DEC / EC (volume ratio 1:1), and the separator was Celgard 2500. The cells were assembled into CR2032 type button cells in an argon-filled glove box. The button cells were first allowed to stand for 12 hours, then charged and discharged at 25°C in a voltage range of 2.5-4.3V. Specific capacity was tested sequentially at 0.1C and 1C rates, followed by 50 cycle tests at 1C rate.

[0046] A comparison of Examples 1 to 5 reveals that high-performance ternary cathode materials for lithium-ion batteries can be obtained using different mixing equipment. The specific capacity and cycle stability of these materials can be optimized by changing the parameters of the mixing or heat treatment processes. Example 6 demonstrates that the solid-state method proposed in this invention can also synthesize nickel-cobalt-aluminum ternary cathode material precursors. Examples 7 to 9 show that the solid-state method proposed in this invention has certain universality and is suitable for synthesizing precursors for high-nickel and / or medium-nickel ternary cathode materials. Comparing Example 1 and Reference Example 1, it can be found that a low amount of solid alkali added reduces the performance of the ternary material. This is because only a sufficient amount can ensure the complete reaction of nickel, cobalt, and manganese, thus forming a structurally stable ternary cathode material precursor. Comparing Example 1 and Reference Example 2, adding a heat treatment process can improve the specific capacity and cycle stability of the ternary cathode material, because higher temperatures promote the solid-state reaction. Comparing Examples 1 and 3-5, it can be seen that the ternary cathode material synthesized using an inorganic solid alkali containing sodium exhibits superior performance compared to other precipitants. This is because other types of alkalis are prone to decomposition into gas during high-temperature heat treatment, and this gas impacts the material structure, compromising its stability. Comparing Example 1 and Reference Example 6, the performance of the ternary cathode material synthesized by the solid-state method in this patent is comparable to that of the traditional liquid co-precipitation method, with lower process costs. The solid-state method has a very promising application prospect.

[0047] The above-described embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention. The scope of protection of the present invention is defined by the claims.

Claims

1. A method for synthesizing ternary cathode material precursors for lithium-ion batteries using a solid-state method, characterized in that, Includes the following steps: (1) Take solid metal salt and solid alkali, add them to a mixing device at a temperature of 0-550℃, and induce them to undergo a solid reaction under continuous stirring to obtain a precipitate; The molar ratio of the solid alkali to the solid metal salt is 1:1 to 10:1, and the mixing time is 5 min to 100 h. (2) The precipitate obtained in step (1) is transferred to a heating furnace and heat-treated at a temperature of 30℃-900℃ to obtain the initial precursor. The heat treatment time is 5min-100h. (3) Take the initial precursor obtained in step (2), wash, filter and dry it with deionized water to obtain the ternary cathode material precursor for lithium-ion batteries.

2. The method for synthesizing lithium-ion battery ternary cathode material precursors using a solid-state method as described in claim 1, characterized in that, The mixing equipment in step (1) is a stirring vessel, a mixer, a pulverizer, a ball mill, or a sand mill.

3. The method for synthesizing lithium-ion battery ternary cathode material precursors using a solid-state method as described in claim 1, characterized in that, The solid metal salt in step (1) has the metal elements Ni, Co, Mn or Al as the main components; Solid alkalis are sodium hydroxide, sodium carbonate, sodium bicarbonate, ammonium carbonate, urea, oxalic acid, potassium carbonate, potassium hydroxide, disodium ethylenediaminetetraacetate, or mixtures thereof.

4. The method for synthesizing lithium-ion battery ternary cathode material precursors using a solid-state method as described in claim 1, characterized in that, If the temperatures in steps (1) and (2) are the same, then the two can be combined.

5. The method for synthesizing lithium-ion battery ternary cathode material precursors using a solid-state method as described in claim 1, characterized in that, When mixing in step (1), the solid alkali can be added to the solid metal salt, the solid metal salt can be added to the solid alkali, or both can be added to the mixing equipment together.

6. The method for synthesizing lithium-ion battery ternary cathode material precursors using a solid-state method as described in claim 1, characterized in that, During the mixing process in step (1), heating conditions are provided to better promote the solid precipitation reaction.

7. The method for synthesizing lithium-ion battery ternary cathode material precursors using a solid-state method as described in claim 1, characterized in that, In the mixing process of step (2), a nitrogen atmosphere is introduced to eliminate the interference of oxygen.

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