阅读说明：本技术 一种高镍三元正极材料的表面处理方法 (Surface treatment method of high-nickel ternary cathode material ) 是由 赵光辉 于 2020-12-10 设计创作，主要内容包括：本发明属于电池材料生产技术领域,涉及一种高镍三元正极材料的表面处理方法；该高镍三元正极材料的表面处理方法,包括基液配制、一次反应凝结、过滤干燥、二次反应凝结和真空干燥的操作步骤,采用碳酸盐溶解在聚酰胺酸溶液中作为基液,然后将高镍三元正极材料投入其中进行一次反应凝结并进行过滤去除其中多余杂质,然后进行干燥处理,这时加入热络合剂再次投入其中进行二次反应凝结并进行真空干燥。这样再经过至少两次的反应凝结和严格的转速、温度以及时间控制可以使其表面形成新的含碳的凝结层,从而有利于提高高镍三元正极材料在使用过程中的化学稳定性,便于进行长时间的反复使用,提高了使用的安全性。(The invention belongs to the technical field of battery material production, and relates to a surface treatment method of a high-nickel ternary cathode material; the surface treatment method of the high-nickel ternary cathode material comprises the operation steps of base solution preparation, primary reaction coagulation, filtering and drying, secondary reaction coagulation and vacuum drying, carbonate is dissolved in polyamic acid solution to serve as base solution, then the high-nickel ternary cathode material is put into the base solution to perform primary reaction coagulation, filtering is performed to remove redundant impurities, then drying is performed, and at the moment, a thermal complexing agent is added into the base solution again to perform secondary reaction coagulation, and vacuum drying is performed. Therefore, a new carbon-containing condensation layer can be formed on the surface of the high-nickel ternary cathode material through at least two times of reaction condensation and strict control of rotating speed, temperature and time, so that the chemical stability of the high-nickel ternary cathode material in the using process is improved, the high-nickel ternary cathode material is convenient to use repeatedly for a long time, and the use safety is improved.)

1. A surface treatment method of a high-nickel ternary cathode material is characterized by comprising the following steps: the method specifically comprises the following steps:

step S1, preparing a base solution: dissolving carbonate in a polyamic acid solution, and stirring for a period of time by a stirrer to uniformly mix the carbonate and the polyamic acid solution to prepare a carbon-containing solution with the concentration content of 0.6-1 mol/L;

step S2, primary reaction coagulation: the weight proportion of the high-nickel ternary positive electrode material to the carbon-containing solution is 0.03: 120, putting the mixture into the carbon-containing solution prepared in the step S1, and continuously stirring the mixture for a period of time at a certain temperature to fully react and coagulate the mixture;

step S3, filtering and drying: filtering the solution condensed in the step S2 through a microporous membrane to obtain a filtered product A, and naturally cooling and drying the product A in a room temperature environment;

step S4, condensation of secondary reaction: putting the product A obtained in the step S3 into the step S1 again, adding a complexing agent, and further reacting and condensing to obtain a product B;

step S5, vacuum drying: and (4) placing the reactant B obtained in the step S4 in a vacuum environment for low-temperature heat treatment, so as to obtain the high-nickel ternary cathode material of the carbon coating layer.

2. The method as claimed in claim 1, wherein in step S1, the carbonate is one of sodium carbonate, potassium carbonate, calcium carbonate, barium carbonate, magnesium carbonate and copper carbonate, and the polyamic acid solution has a solid content of 0.002-0.006%.

3. The method as claimed in claim 2, wherein the step S1 is performed by using a stirrer rotating at 800rpm for 0.5-1.5 h.

4. The method for surface treatment of a high-nickel ternary positive electrode material as claimed in claim 1, wherein the high-nickel ternary positive electrode material is LiNi_xCo_y Mn_1-x-yWherein x is more than or equal to 0.4 and less than or equal to 0.85, and y is more than or equal to 0 and less than or equal to 0.3.

5. The method as claimed in claim 1, wherein in step S2, the stirring speed is controlled at 300-600 rpm/S, the stirring time is 1-3h, and the stirring temperature is controlled at 60-80 ℃.

6. The surface treatment method of the high-nickel ternary cathode material as claimed in claim 1, wherein the pore size of the microporous membrane in step S3 is 0.22um, the obtained product a is filtered to remove substances smaller than the product a, and the product a is naturally dried in an environment at room temperature of 20-40 ℃.

7. The method as claimed in claim 1, wherein the complexing agent in step S4 is one of cyanide, hydroxide, citrate, pyrophosphate, ammonia, thiosulfate and sulfite, preferably ammonia.

8. The method as claimed in claim 1, wherein the low temperature heat treatment in step S5 is performed at 200-300 ℃ for 2-5 h.

Technical Field

The invention belongs to the technical field of battery material production, and particularly relates to a surface treatment method of a high-nickel ternary cathode material.

Background

The battery using nickel-cobalt-manganese ternary battery material as the positive electrode has high safety compared with a lithium cobaltate battery, but the platform is too low, and the battery has obvious feeling of insufficient capacity when being used on a mobile phone (the cut-off voltage of the mobile phone is generally about 3.4V), and batteries using ternary materials, particularly batteries with higher capacity, are already available on some emulational mobile phones. The conventional battery positive electrode material is lithium cobaltate LiCoO₂The ternary material is nickel cobalt lithium manganate Li (NiCoMn) O₂Precursor of ternary composite positive electrode materialThe bulk product takes nickel salt, cobalt salt and manganese salt as raw materials, the proportion of nickel, cobalt and manganese in the bulk product can be adjusted according to actual needs, the capacity of lithium iron phosphate is exerted to a low extent, and the bulk product is not suitable for pursuing the requirement of a high-capacity mobile phone battery.

The high-nickel ternary positive electrode material is a preferred system of a high-energy-density power battery system due to the relatively low cost and high energy density, and has attracted extensive attention. However, the increase of nickel content in the material and the addition of excessive lithium source during sintering prevent the ion mixing caused by lithium volatilization, thereby leading to high lithium content on the surface of the high-nickel ternary material. Meanwhile, the surface residual alkali and water and CO in the air are mixed during the storage process of the material₂Further reaction to give Li₂O and Li₂CO₃And the like, which can generate a series of side reactions with the electrolyte in the battery circulation process, consume the electrolyte and generate a CEI film with complex components and uneven thickness on the surface, reduce the activity of the material interface, cause the electrochemical performance to deteriorate and limit the practical application of the high-nickel ternary cathode material.

The lithium ion battery adopts materials capable of reversibly inserting and extracting lithium ions as a positive electrode material and a negative electrode material of the battery, and is combined with a proper electrolyte or a solid electrolyte powder film to form a lithium ion secondary battery system. Since the energy of a battery depends on the product of its voltage and capacity, a means for increasing the energy density of the battery is to use positive and negative electrode materials of high voltage and high capacity. For the same negative electrode material, the higher the capacity and potential of the positive electrode material, the higher the energy density of the battery. The energy density of the lithium ion battery is improved, and the development of the ternary cathode powder with higher specific capacity and high nickel content is the main direction of battery research and development.

The existing surface treatment method of the high-nickel ternary cathode material can only remove residual alkali on the surface of the material, cannot form on the surface of the high-nickel ternary cathode material, and relatively stabilizes new substances, so that the chemical stability of the high-nickel ternary cathode material is easily reduced in the long-time recycling process, and the use safety and reliability of the high-nickel ternary cathode material are seriously influenced.

Disclosure of Invention

The invention aims to solve the defects in the prior art and provides a surface treatment method of a high-nickel ternary cathode material.

In order to achieve the purpose, the invention provides the following technical scheme:

the invention provides a surface treatment method of a high-nickel ternary cathode material, which specifically comprises the following steps:

1. a surface treatment method of a high-nickel ternary cathode material is characterized by comprising the following steps: the method specifically comprises the following steps:

step S1, preparing a base solution: dissolving carbonate in a polyamic acid solution, and stirring for a period of time by a stirrer to uniformly mix the carbonate and the polyamic acid solution to prepare a carbon-containing solution with the concentration content of 0.6-1 mol/L;

step S2, primary reaction coagulation: the weight proportion of the high-nickel ternary positive electrode material to the carbon-containing solution is 0.03: 120, putting the mixture into the carbon-containing solution prepared in the step S1, and continuously stirring the mixture for a period of time at a certain temperature to fully react and coagulate the mixture;

step S3, filtering and drying: filtering the solution condensed in the step S2 through a microporous membrane to obtain a filtered product A, and naturally cooling and drying the product A in a room temperature environment;

step S4, condensation of secondary reaction: putting the product A obtained in the step S3 into the step S1 again, adding a complexing agent, and further reacting and condensing to obtain a product B;

step S5, vacuum drying: and (4) placing the reactant B obtained in the step S4 in a vacuum environment for low-temperature heat treatment, so as to obtain the high-nickel ternary cathode material of the carbon coating layer.

In one embodiment of the present invention, in step S1, the carbonate is one of sodium carbonate, potassium carbonate, calcium carbonate, barium carbonate, magnesium carbonate and copper carbonate, and the polyamic acid solution has a solid content of 0.002-0.006%.

In an embodiment of the present invention, in step S1, a stirrer with a rotation speed of 800rpm is used, and the stirring time is 0.5-2 h.

In the present inventionIn one embodiment, the high nickel ternary positive electrode material is LiNi_xCo_y Mn_1-x-yWherein x is more than or equal to 0.4 and less than or equal to 0.85, and y is more than or equal to 0 and less than or equal to 0.3.

In one embodiment of the present invention, in the step S2, the stirring speed is controlled at 600 rpm/S, the stirring time is 0.8-8h, and the stirring temperature is controlled at 60-80 ℃.

In one embodiment of the present invention, the pore size of the microporous membrane in step S3 is 0.22um, the obtained product a is filtered to remove substances smaller than the product a, and the product a is naturally dried in the environment at room temperature of 20-35 ℃.

In one embodiment of the present invention, the complexing agent in step S4 is one of cyanide, hydroxide, citrate, pyrophosphate, ammonia, thiosulfate and sulfite, and ammonia is preferred.

In one embodiment of the present invention, in step S3, the mixture is stirred for 2 hours by a stirrer with a rotation speed of 300rpm, and the reaction temperature is controlled between 70 ℃ and 90 ℃.

In one embodiment of the present invention, the low temperature heat treatment in step S5 is performed at 200-300 ℃ for 2-5 h.

The invention has the technical effects and advantages that:

the invention dissolves carbonate in the polyamic acid solution, the mixture is stirred for a period of time by a stirrer to be uniformly mixed to prepare a carbon-containing solution with the concentration content of 0.6-1mol/L, and then the weight proportion of the high-nickel ternary cathode material to the carbon-containing solution is 0.03: 120, putting the solution obtained by reaction coagulation in the step S2 into the carbonaceous solution prepared in the step S1, continuously stirring the solution at a certain temperature for a period of time to fully react and coagulate the solution, filtering the solution through a microporous membrane to obtain a filtered product A, placing the product A in a room temperature environment for natural cooling and drying, then putting the product A obtained in the step S3 into the step S1 again, adding a complexing agent to further react and coagulate the product B to obtain a product B, then placing the reactant B obtained in the step S4 in a vacuum environment for low-temperature heat treatment to obtain the high-nickel ternary positive electrode material of the carbon wrapping layer, thus in the surface treatment process of the high-nickel ternary positive electrode material, adding the high-nickel ternary positive electrode material into the carbonaceous solution to fully react and coagulate the high-nickel ternary positive electrode material, drying the high-nickel ternary positive electrode material, and heating the complexing agent to re-react and coagulate the dried high-nickel ternary positive electrode material again, therefore, a new carbon-containing condensation layer can be formed on the surface of the high-nickel ternary cathode material, so that the chemical stability of the high-nickel ternary cathode material in the using process is improved, the high-nickel ternary cathode material is convenient to use repeatedly for a long time, and the use safety is improved.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The specific embodiments described herein are merely illustrative of the invention and do not delimit the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example one

A surface treatment method of a high-nickel ternary cathode material specifically comprises the following steps:

step S1, preparing a base solution: dissolving carbonate in a polyamic acid solution, and stirring for a period of time by using a stirrer to uniformly mix the carbonate and the polyamic acid solution to prepare a carbon-containing solution with the concentration content of 0.6 mol/L;

step S2, primary reaction coagulation: the weight proportion of the high-nickel ternary positive electrode material to the carbon-containing solution is 0.01: 80, putting the mixture into the carbon-containing solution prepared in the step S1, and continuously stirring the mixture for a period of time at a certain temperature to fully react and coagulate the mixture;

step S3, filtering and drying: filtering the solution condensed in the step S2 through a microporous membrane to obtain a filtered product A, and naturally cooling and drying the product A in a room temperature environment;

step S4, condensation of secondary reaction: putting the product A obtained in the step S3 into the step S1 again, adding a complexing agent, and further reacting and condensing to obtain a product B;

step S5, vacuum drying: and (4) placing the reactant B obtained in the step S4 in a vacuum environment for low-temperature heat treatment, so as to obtain the high-nickel ternary cathode material of the carbon coating layer.

In one embodiment of the present invention, in step S1, the carbonate is one of sodium carbonate, potassium carbonate, calcium carbonate, barium carbonate, magnesium carbonate and copper carbonate, and the polyamic acid solution has a solid content of 0.002%.

In an embodiment of the present invention, in step S1, a stirrer with a rotation speed of 800rpm is used, and the stirring time is 0.5 h.

In one embodiment of the present invention, the high nickel ternary positive electrode material is LiNi_xCo_y Mn_1-x-yWherein x is more than or equal to 0.4 and less than or equal to 0.85, and y is more than or equal to 0 and less than or equal to 0.3.

In one embodiment of the present invention, in step S2, the stirring speed is controlled at 300 rpm/S, the stirring time is 1h, and the stirring temperature is controlled at 60-80 ℃.

In one embodiment of the present invention, the pore size of the microporous membrane in step S3 is 0.22um, the obtained product a is filtered to remove substances smaller than the product a, and the product a is naturally dried in the environment at room temperature of 20-40 ℃.

In one embodiment of the present invention, the complexing agent in step S4 is one of cyanide, hydroxide, citrate, pyrophosphate, ammonia, thiosulfate and sulfite, and ammonia is preferred.

In one embodiment of the present invention, the low temperature heat treatment in step S5 is performed at 200-300 ℃ for 2-5 h.

Example two

A surface treatment method of a high-nickel ternary cathode material specifically comprises the following steps:

step S1, preparing a base solution: dissolving carbonate in a polyamic acid solution, and stirring for a period of time by using a stirrer to uniformly mix the carbonate and the polyamic acid solution to prepare a carbon-containing solution with the concentration content of 0.8 mol/L;

step S2, primary reaction coagulation: the weight proportion of the high-nickel ternary positive electrode material to the carbon-containing solution is 0.02: 100, putting the carbon-containing solution prepared in the step S1 into the carbon-containing solution, and continuously stirring the solution for a period of time at a certain temperature to fully react and coagulate the solution;

step S3, filtering and drying: filtering the solution condensed in the step S2 through a microporous membrane to obtain a filtered product A, and naturally cooling and drying the product A in a room temperature environment;

step S4, condensation of secondary reaction: putting the product A obtained in the step S3 into the step S1 again, adding a complexing agent, and further reacting and condensing to obtain a product B;

step S5, vacuum drying: and (4) placing the reactant B obtained in the step S4 in a vacuum environment for low-temperature heat treatment, so as to obtain the high-nickel ternary cathode material of the carbon coating layer.

In one embodiment of the present invention, in step S1, the carbonate is one of sodium carbonate, potassium carbonate, calcium carbonate, barium carbonate, magnesium carbonate and copper carbonate, and the polyamic acid solution has a solid content of 0.004%.

In an embodiment of the present invention, in step S1, a stirrer with a rotation speed of 800rpm is used, and the stirring time is 1 h.

In one embodiment of the present invention, the high nickel ternary positive electrode material is LiNi_xCo_y Mn_1-x-yWherein x is more than or equal to 0.4 and less than or equal to 0.85, and y is more than or equal to 0 and less than or equal to 0.3.

In one embodiment of the present invention, in step S2, the stirring speed is controlled at 450 rpm, the stirring time is 2 hours, and the stirring temperature is controlled at 60-80 ℃.

In one embodiment of the present invention, the pore size of the microporous membrane in step S3 is 0.22um, the obtained product a is filtered to remove substances smaller than the product a, and the product a is naturally dried in the environment at room temperature of 20-40 ℃.

In one embodiment of the present invention, the complexing agent in step S4 is one of cyanide, hydroxide, citrate, pyrophosphate, ammonia, thiosulfate and sulfite, and ammonia is preferred.

In one embodiment of the present invention, the low temperature heat treatment in step S5 is performed at 200-300 ℃ for 2-5 h.

EXAMPLE III

A surface treatment method of a high-nickel ternary cathode material specifically comprises the following steps:

step S1, preparing a base solution: dissolving carbonate in a polyamic acid solution, and stirring for a period of time by using a stirrer to uniformly mix the carbonate and the polyamic acid solution to prepare a carbon-containing solution with the concentration content of 1 mol/L;

step S2, primary reaction coagulation: the weight proportion of the high-nickel ternary positive electrode material to the carbon-containing solution is 0.03: 120, putting the mixture into the carbon-containing solution prepared in the step S1, and continuously stirring the mixture for a period of time at a certain temperature to fully react and coagulate the mixture;

step S3, filtering and drying: filtering the solution condensed in the step S2 through a microporous membrane to obtain a filtered product A, and naturally cooling and drying the product A in a room temperature environment;

step S4, condensation of secondary reaction: putting the product A obtained in the step S3 into the step S1 again, adding a complexing agent, and further reacting and condensing to obtain a product B;

step S5, vacuum drying: and (4) placing the reactant B obtained in the step S4 in a vacuum environment for low-temperature heat treatment, so as to obtain the high-nickel ternary cathode material of the carbon coating layer.

In one embodiment of the present invention, in step S1, the carbonate is one of sodium carbonate, potassium carbonate, calcium carbonate, barium carbonate, magnesium carbonate and copper carbonate, and the polyamic acid solution has a solid content of 0.006%.

In an embodiment of the present invention, in step S1, a stirrer with a rotation speed of 800rpm is used, and the stirring time is 1.5 h.

In one embodiment of the present invention, the high nickel IIIThe meta-positive electrode material is LiNi_xCo_y Mn_1-x-yWherein x is more than or equal to 0.4 and less than or equal to 0.85, and y is more than or equal to 0 and less than or equal to 0.3.

In one embodiment of the present invention, in step S2, the stirring speed is controlled at 600 rpm/S, the stirring time is 3 hours, and the stirring temperature is controlled at 60-80 ℃.

In one embodiment of the present invention, the pore size of the microporous membrane in step S3 is 0.22um, the obtained product a is filtered to remove substances smaller than the product a, and the product a is naturally dried in the environment at room temperature of 20-40 ℃.

In one embodiment of the present invention, the complexing agent in step S4 is one of cyanide, hydroxide, citrate, pyrophosphate, ammonia, thiosulfate and sulfite, and ammonia is preferred.

In one embodiment of the present invention, the low temperature heat treatment in step S5 is performed at 200-300 ℃ for 2-5 h.

During preparation, carbonate is dissolved in a polyamic acid solution, the polyamic acid solution is stirred for a period of time by a stirrer to be uniformly mixed to prepare a carbon-containing solution with the concentration content of 0.6-1mol/L, and then the weight proportion of the high-nickel ternary cathode material to the carbon-containing solution is 0.03: 120, putting the solution obtained by reaction coagulation in the step S2 into the carbonaceous solution prepared in the step S1, continuously stirring the solution at a certain temperature for a period of time to fully react and coagulate the solution, filtering the solution through a microporous membrane to obtain a filtered product A, placing the product A in a room temperature environment for natural cooling and drying, then putting the product A obtained in the step S3 into the step S1 again, adding a complexing agent to further react and coagulate the product B to obtain a product B, then placing the reactant B obtained in the step S4 in a vacuum environment for low-temperature heat treatment to obtain the high-nickel ternary positive electrode material of the carbon wrapping layer, thus in the surface treatment process of the high-nickel ternary positive electrode material, adding the high-nickel ternary positive electrode material into the carbonaceous solution to fully react and coagulate the high-nickel ternary positive electrode material, drying the high-nickel ternary positive electrode material, and heating the complexing agent to re-react and coagulate the dried high-nickel ternary positive electrode material again, therefore, a new carbon-containing condensation layer can be formed on the surface of the high-nickel ternary cathode material, so that the chemical stability of the high-nickel ternary cathode material in the using process is improved, the high-nickel ternary cathode material is convenient to use repeatedly for a long time, and the use safety is improved.

Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments or portions thereof without departing from the spirit and scope of the invention.