阅读说明：本技术 正极材料、其制备方法及锂离子电池 (Cathode material, preparation method thereof and lithium ion battery ) 是由 王淑慧 彭祖铃 王涛 刘可禄 闫银贤 牛从酥 于 2020-06-24 设计创作，主要内容包括：本发明提供一种正极材料的制备方法,包括：将除去壳体的废旧锂离子电池破碎,用硝酸处理破碎后的碎料,将金属元素溶解,过滤后得到滤液；向所述滤液中加入磷酸氨或磷酸,用氨水控制pH值在7.5～10,反应后过滤得到沉淀物A和滤液B。还提供该方法制备的正极材料和包含该正极材料的锂离子电池。本发明以废旧电池为原料制备正极材料,采用控制pH值的方法,将锰和铁元素进行分离,分离出的锰元素成为新合成三元材料的内核,并将生产过程中引入的Fe进行利用,合成磷酸锰铁锂,既达到除铁的效果又对废物进行利用,节约资源保护环境。(The invention provides a preparation method of a positive electrode material, which comprises the following steps: crushing the waste lithium ion battery without the shell, treating crushed materials with nitric acid, dissolving metal elements, and filtering to obtain filtrate; and adding ammonium phosphate or phosphoric acid into the filtrate, controlling the pH value to be 7.5-10 by using ammonia water, and filtering after reaction to obtain a precipitate A and a filtrate B. Also provided are a cathode material prepared by the method and a lithium ion battery containing the cathode material. According to the invention, the anode material is prepared by taking the waste battery as a raw material, manganese and iron elements are separated by adopting a method for controlling the pH value, the separated manganese elements become the inner core of a new synthetic ternary material, and Fe introduced in the production process is utilized to synthesize the lithium iron manganese phosphate, so that the iron removal effect is achieved, the waste is utilized, the resource is saved, and the environment is protected.)

1. A method for preparing a positive electrode material, comprising:

crushing the waste lithium ion battery without the shell, treating crushed materials with acid, and dissolving metal elements to obtain a mixed solution; and

and adding ammonium phosphate or phosphoric acid into the mixed solution, controlling the pH value to be 7.5-10 by using ammonia water, and filtering after reaction to obtain a precipitate A and a filtrate B.

2. The preparation method according to claim 1, wherein the waste lithium ion battery is a lithium ion battery with a ternary material as a positive electrode active material.

3. The production method according to claim 1 or 2, characterized by further comprising:

and sintering the precipitate A and lithium salt which can be decomposed by heating in protective gas to obtain a product C.

4. The method according to claim 3, wherein an aldehyde is added to the filtrate B, a copper mirror reaction occurs, and a precipitate and a filtrate D are obtained by filtration.

5. The method according to claim 4, wherein the aldehyde is an aldehyde having 5 or more carbon atoms.

6. The preparation method according to claim 5, wherein the aldehyde is one or more selected from glutaraldehyde, citral, and glucose.

7. The method as claimed in claim 4, wherein the product C is added to the filtrate D for evaporation and crystallization, and after the solution is dried, the solution is sintered at 600-800 ℃ under an inert atmosphere.

8. The method according to claim 3, wherein the lithium salt decomposable by heating is one or more selected from lithium carbonate, lithium hydroxide, lithium formate, lithium acetate and lithium oxalate.

9. A positive electrode material produced by the method according to any one of claims 1 to 8.

10. A lithium ion battery comprising the positive electrode material according to claim 9.

Technical Field

The invention belongs to the field of chemical power sources, and particularly relates to a positive electrode material, a preparation method thereof and a lithium ion battery.

Background

At present, the wide use of lithium ion batteries tends to bring a large amount of waste batteries, if the waste batteries are discarded at will, the environment is seriously polluted, and resources are wasted. Lithium ion batteries contain a large amount of metal resources such as cobalt (Co), copper (Cu), lithium (Li), and nickel (Ni). If the precious metals with high economic value in the waste lithium ion batteries can be recycled, the method has great significance in the aspects of environmental protection and resource recycling.

Disclosure of Invention

In order to overcome the defects, the invention provides a preparation method of a positive electrode material, the positive electrode material prepared by the method and a lithium ion battery containing the positive electrode material.

The invention provides a preparation method of a cathode material, which comprises the following steps: crushing the waste lithium ion battery without the shell, treating crushed materials with acid, dissolving metal elements, and filtering to obtain filtrate; and adding ammonium phosphate or phosphoric acid into the filtrate, controlling the pH value to be 7.5-10 by using ammonia water, and filtering after reaction to obtain a precipitate A and a filtrate B.

The invention also provides a positive electrode material prepared by the method.

The invention also provides a lithium ion battery which comprises the cathode material.

According to the invention, the anode material is prepared by taking the waste battery as a raw material, manganese and iron elements are separated by adopting a method for controlling the pH value, the separated manganese elements become the inner core of a new synthetic ternary material, and Fe introduced in the production process is utilized to synthesize the lithium iron manganese phosphate, so that the iron removal effect is achieved, the waste is utilized, the resource is saved, and the environment is protected. The method of the invention can directly crush the lithium ion battery without the shell, does not need sorting, and is suitable for industrial production. The method utilizes all components of the aluminum foil, the copper foil, the diaphragm and the inactive substances including the adhesive and the conductive agent, and does not generate new pollution in the process.

Drawings

Fig. 1 is an XRD pattern of the cathode material prepared in example 1.

Fig. 2 is a graph of discharge capacity versus cycle number for the positive electrode materials of example 1 and comparative example 1.

Detailed Description

The present invention will be described in detail with reference to the following embodiments.

The 'waste lithium ion battery' in the patent comprises waste lithium ion batteries, such as pole pieces with problems before battery formation, including pole pieces with unqualified coating, pole pieces with problems generated by rolling, pole pieces with problems generated in the assembly process, and the like; also included are old lithium ion batteries, such as batteries that have been formed, classified, have problems during cycling, and are decommissioned after injection.

The preparation method of the cathode material comprises the following steps: crushing the waste lithium ion battery without the shell, treating crushed materials with acid, and dissolving metal elements to obtain a mixed solution; and adding ammonium phosphate or phosphoric acid into the mixed solution, controlling the pH value to be 7.5-10 by using ammonia water, and filtering after reaction to obtain a precipitate A and a filtrate B. The invention takes the waste lithium ion battery as the raw material, the shell of the waste lithium ion battery is removed, and then the battery is crushed. The material can be crushed using any suitable equipment, for example a crusher, the size of the crushed material being specifically selected by the skilled person according to the actual need.

After the crushing, the crushed raw material is dissolved with an acid, and in one embodiment, the acid is an acid capable of dissolving Cu metal, such as but not limited to nitric acid, perchloric acid, and the like, so that all Cu, Ni, Co, Mn, Al, Li, and a small amount of Fe are dissolved in the raw material.

In another embodiment, the acid used is an acid that can dissolve the oxide of Cu, and organic and inorganic acids such as, but not limited to, hydrochloric acid, nitric acid, sulfuric acid, formic acid, acetic acid, and the like can be used.

In order to increase the reaction rate, the reaction mixture may be stirred, for example, at a rotation speed of 50rpm to 100rpm for 24 to 36 hours, to dissolve the metal elements Cu, Ni, Co, Mn, Al, Li and a small amount of Fe in the raw materials. After the reaction is completed, a mixed solution containing the metal ions is obtained.

And adding ammonium phosphate or phosphoric acid into the mixed solution, and controlling the pH value of the reaction by adopting ammonia water, wherein the pH value is controlled to be 7.5-10. Manganese phosphate, iron phosphate and a small amount of lithium phosphate precipitate due to the inability of manganese/iron ions to form complexes with ammonia and the limited ability of lithium phosphate to complex with ammonia. In order to accelerate the reaction, the reaction temperature may be increased, for example, to 80 to 100 ℃. In the step, manganese and iron elements are separated from other elements by a method of controlling the pH value to obtain precipitates of manganese phosphate and iron phosphate, Fe introduced in the production process is utilized to synthesize lithium manganese iron phosphate, so that the effect of removing iron is achieved, wastes are utilized, resources are saved, and the environment is protected. After the reaction was completed, filtration was performed to obtain a precipitate a and a filtrate B. The precipitate A is manganese phosphate, iron phosphate, graphite, a diaphragm, a binder, a conductive agent and the like. The filtrate B is a metal ion ammonia water phosphate complex solution containing copper, nickel, cobalt, aluminum and lithium.

The precipitate a may then be sintered with a lithium salt that can be decomposed by heating in a protective gas to give a product C. The lithium salt that can be decomposed by heating may be one or more of lithium carbonate, lithium hydroxide, lithium formate, lithium acetate, lithium oxalate, and the like, but is not limited thereto. And carbonizing the diaphragm, the binder and the conductive agent in the precipitate A in the sintering process to form a carbon material, thereby obtaining a product C of the carbon-doped lithium manganese iron phosphate. One skilled in the art can select a proper proportion to mix with a proper lithium salt according to the content of each component in the raw material, so as to obtain the product C of the carbon-doped lithium manganese iron phosphate with a predetermined component content.

For filtrate B, aldehyde may be added to perform a copper mirror reaction. The aldehyde may be formaldehyde, acetaldehyde or the like, and the aldehyde is preferably an aldehyde having 5 or more carbon atoms, for example, glucose, glutaraldehyde, citral or the like. The aldehyde organic is added to remove copper ions, on the one hand, and to serve as a carbon source, on the other hand. The reaction temperature can be controlled between 60 ℃ and 80 ℃, and Cu are obtained by filtering after the reaction₂Precipitate O and filtrate D. In the step, Cu in the solution can be removed, so that the nickel, cobalt, aluminum and lithium remained in the solution can be reused.

After the copper mirror reaction, the filtrate D also contains metal ions of nickel, cobalt, aluminum and lithium, ammonia water phosphate complex, excessive aldehyde which does not produce the copper mirror reaction and/or acid produced after the copper mirror reaction. And adding the obtained product C of the carbon-doped lithium manganese iron phosphate into the filtrate D for evaporation crystallization, and sintering at 600-800 ℃ in an inert atmosphere after the solution is dried. And finally, obtaining the carbon-doped lithium manganese iron phosphate as the core and the nickel-cobalt lithium aluminate-coated composite material.

The copper mirror reaction is adopted to remove copper, and simultaneously carbon-containing organic matters are introduced, wherein the carbon-containing organic matters can be at least one of excessive aldehyde which does not generate the copper mirror reaction and acid generated after the copper mirror reaction, so that the final product is coated. Therefore, the side reaction of the lithium iron manganese phosphate and the electrolyte is improved by coating the ternary material.

The invention also protects the anode material prepared by the method.

The cathode material can be used in lithium ion batteries.

The method of the invention can directly crush the lithium ion battery without the shell, does not need sorting, and is suitable for industrial production. The method utilizes the aluminum foil, the copper foil, the diaphragm and the active substances including the adhesive and the conductive agent as the whole components, and does not generate new pollution in the process.

Furthermore, a copper mirror reaction is adopted to remove copper and simultaneously introduce a carbon-containing organic matter, so that the final product is coated. Therefore, the side reaction of the lithium iron manganese phosphate and the electrolyte is improved by coating the ternary material. The lithium ion battery using the anode material has excellent cycle performance and long service life.