A method for regenerating and synthesizing positive electrode material precursors using waste ternary lithium batteries

Abstract

The invention discloses a method for synthesizing a positive electrode material precursor by regenerating waste ternary lithium batteries, using an organic acid-hydrogen peroxide system to leach positive electrode material powder, filtering to obtain a first mixed solution, adding a manganese ion sieve adsorbent to the first mixed solution, filtering to obtain a second mixed solution, adding a manganese precipitant and a citrate buffered saline solution to the second mixed solution, filtering to obtain a third mixed solution, performing metal ion quantitative analysis on the third mixed solution, obtaining a nickel-cobalt-manganese ion ratio, supplementing nickel or / and manganese to the third mixed solution, and finally preparing by spray drying. The present invention uses an organic acid-hydrogen peroxide system to leach positive electrode powder, then first precipitates and recovers part of manganese ions and impurity metals through a manganese precipitant, and then regenerates the positive electrode material precursor by supplementing nickel. The method has a simple process, effectively reduces the input cost, and the quality of the obtained regenerated product is significantly improved, which increases the profit of the enterprise.

Description

Technical Field

[0001] The invention relates to the technical field of waste battery recycling, and in particular to a method for regenerating and synthesizing anode material precursors by utilizing waste ternary lithium batteries. Background Art

[0002] Waste lithium-ion batteries are rich in precious metals such as nickel, cobalt, and lithium, and their content is even much higher than that in natural ores. If recycled reasonably, it can greatly alleviate the current shortage of nickel, cobalt, and lithium resources in my country. At the same time, the organic solvents and heavy metals in waste lithium-ion batteries will cause certain pollution to the soil, water sources, and air. If not handled properly, waste lithium-ion batteries will also become an important environmental pollutant. In summary, whether from the perspective of economic value or environmental protection, the reasonable recycling and reuse of waste lithium batteries is an important issue that needs to be solved urgently. Since the precious metals in waste lithium-ion batteries are mainly concentrated in the positive electrode materials, the recycling and utilization of waste lithium-ion battery positive electrode materials has become an important part of the recycling and resource utilization of lithium-ion batteries. At present, there are many recycling processes for waste lithium-ion batteries, which are mainly divided into physical processes and chemical processes. The physical process mainly refers to the front-end pretreatment stage of lithium-ion batteries, including: safe disassembly, crushing and separation, heat treatment and other processes; the chemical process is the recycling and utilization stage of lithium-ion battery positive electrode materials, including: dissolution process, extraction process, chemical precipitation process, biological leaching process, etc. Among them, hydrometallurgy is the main research direction because of its advantages such as high recovery rate, low power consumption, low equipment operating cost and simple process flow.

[0003] In the hydrometallurgical recycling process, the leaching of positive electrode material powder usually adopts an inorganic acid-reducing agent leaching system. This system urgently needs to solve the problem that inorganic acids will produce a large amount of sulfur oxides, nitrogen oxides, etc., which will cause secondary pollution to the environment. At the same time, when using waste batteries to regenerate nickel-cobalt-manganese ternary batteries, the usual practice is to conduct quantitative analysis of metal ions in the leachate by ICP-OES, and then regenerate product-grade positive electrode materials by adding metal ions according to the molar ratio of each metal ion. Although this method can regenerate positive electrode materials, in actual applications, due to the large difference in the molar ratio of each metal ion, a large amount of lithium, nickel, cobalt and other metals need to be added, which undoubtedly increases the material cost of battery recycling companies to purchase these metal products, resulting in low profit margins and high investment costs for battery recycling companies. It is not a preferred choice. Moreover, during the regeneration process, the positive electrode material obtained contains trace amounts of doped metal ions such as iron, aluminum, and copper, which leads to structural instability of the positive electrode material during the cycle process. The cycle performance of the recycled positive electrode material is inferior to that of similar products prepared directly, thereby reducing the quality of the finished product and the profits of the recycling company. Therefore, how to reasonably and efficiently recycle and reuse the valuable metals on the positive electrode material has become an important research direction for the recycling and reuse of waste lithium batteries. Summary of the invention

[0004] The purpose of the present invention is to provide a method for regenerating and synthesizing anode material precursors by using waste ternary lithium batteries to solve the above-mentioned problems. The present invention adopts an organic acid-hydrogen peroxide system to leach cathode powder, and then removes lithium ions by a manganese ion sieve adsorbent before regenerating and preparing cathode material precursors. Then, a manganese precipitant and a citrate buffer solution are used to precipitate and recover part of manganese and doped metals. Finally, the cathode material precursor is regenerated by supplementing nickel or manganese (manganese is supplemented when there is too much manganese precipitation). The method has a simple process, effectively reduces the investment cost, does not generate secondary pollution, and significantly improves the quality of the regenerated product, thereby increasing the profit of the enterprise and overcoming the shortcomings of the existing recycling and regeneration process.

[0005] The technical scheme adopted by the present invention is as follows: a method for regenerating and synthesizing a positive electrode material precursor by using waste ternary lithium batteries, characterized in that the waste lithium batteries are pretreated to obtain positive electrode material powder, the positive electrode material powder is leached by an organic acid-hydrogen peroxide system, and a first mixed solution is obtained by filtering, a manganese ion sieve adsorbent is added to the first mixed solution, lithium ions are removed and the second mixed solution is obtained by filtering, a manganese precipitant and a citrate buffer solution are added to the second mixed solution, after part of the manganese ions are precipitated, a third mixed solution is obtained by filtering, nickel and / or manganese are supplemented to the third mixed solution, and finally a high-nickel positive electrode material precursor is prepared by a spray drying method.

[0006] In the present invention, the most important innovation is that after obtaining the first mixed solution, the lithium in the solution is first removed by a manganese ion sieve adsorbent. This technology belongs to the prior art. For example, you can refer to the existing document "Research Progress on Preparation of Lithium Ion Sieves from Waste Lithium Ion Batteries and Their Applications" (Zhou Lei, Yuan Yongshun, etc., Inorganic Salt Industry, Volume 54, No. 8, August 2022). The manganese ion sieve adsorbent and the process of removing lithium ions will not be described in detail here. Those skilled in the art can select suitable reagents according to the applicable scope of each manganese ion sieve adsorbent. Furthermore, a manganese precipitant and a citrate buffer solution are added to the second mixed solution after lithium removal. While reducing the manganese content in the mixed solution, the manganese ion adsorbent will be dissolved and enter the solution, and the manganese precipitant can precipitate the manganese ions entering the solution, thereby controlling the amount of manganese ions. There is no need to add cobalt and manganese metal ions subsequently. By adding nickel ions (manganese is supplemented when there is too much manganese precipitation), high-nickel positive electrode materials are regenerated, thereby greatly reducing the amount of metal ions added. The obtained manganese precipitate can be directly recovered without generating waste, effectively reducing the cost of recycling valuable metals for enterprises, and the high-nickel positive electrode material products obtained by regeneration have higher added value, thereby increasing the profit margin of enterprises, and are more practical. At the same time, when precipitating manganese ions, the inventors found that under certain precipitation conditions (and citrate buffer salt solution conditions), iron, aluminum, and copper metal ions will precipitate together with manganese ions, and the iron, aluminum, and copper metal ions in the obtained high-nickel positive electrode material are controlled within an extremely low content range. This makes the method of the present invention not only have lower process investment costs compared to existing recovery and regeneration methods, but also have better quality and higher value of the regenerated products, and have more outstanding technical advantages.

[0007] In the present invention, when partial precipitation of manganese ions is performed, the manganese precipitant will preferentially precipitate different metal ions under different pH conditions. The present invention controls the pH value of the solution system to neutral or slightly acidic so that the manganese precipitant will preferentially precipitate manganese ions. At the same time, a citrate buffer solution is used to stabilize the pH change of the precipitation process, thereby avoiding the precipitation of part of the cobalt ions and nickel ions due to the pH change, thereby effectively improving the manganese ion precipitation effect.

[0008] Furthermore, the present invention controls the amount of manganese ions precipitated by controlling the amount of manganese precipitant, thereby preventing excessive precipitation of manganese ions and avoiding the precipitation of cobalt ions and nickel ions when a small amount of manganese ions is present. Ultimately, the molar ratio of nickel ions, cobalt ions and manganese ions in the solution can meet the requirements of high-nickel positive electrode materials only by supplementing nickel ions, thereby greatly reducing the use of precious metals and effectively reducing enterprise costs.

[0009] Furthermore, in the present invention, the organic acid is selected from one or more of citric acid, malic acid, and succinic acid, the manganese-cobalt precipitant is one or more of ammonium oxalate and ammonium bicarbonate, and the manganese precipitant is preferably ammonium bicarbonate.

[0010] Furthermore, the method for regenerating anode materials from waste ternary lithium batteries of the present invention comprises the following steps:

[0011] A. Pre-treating the waste ternary lithium battery to obtain positive electrode material powder, then leaching the positive electrode material powder with an organic acid-hydrogen peroxide system, filtering to obtain a first mixed solution, adding a manganese ion sieve adsorbent to the first mixed solution, removing lithium ions and filtering to obtain a second mixed solution;

[0012] B. adding a manganese precipitant and a citrate buffer solution to the second mixed solution to stabilize the pH value of the solution at 6.5-7.5, and filtering the precipitate to obtain a third mixed solution;

[0013] C. Analyze the molar ratio of each metal ion in the third mixed solution, and then add nickel ions and / or manganese ions to the third mixed solution so that the molar ratio of nickel ions, cobalt ions, and manganese ions meets the product requirements of high-nickel positive electrode materials, and then prepare a high-nickel positive electrode material precursor by spray drying.

[0014] Further, in step A, the organic acid concentration is 3-6 mol / L (for example, 3 mol / L, 3.5 mol / L, 4 mol / L, 5 mol / L, 5.5 mol / L, 6 mol / L, etc.), the hydrogen peroxide concentration is 10-25 vol% (for example, 10 vol%, 15 vol%, 18 vol%, 20 vol%, 25 vol%, etc.), the pickling temperature is 40-70°C (for example, 40°C, 45°C, 48°C, 50°C, 55°C, 60°C, 70°C, etc.), the pickling time is 1-5h (for example, 1h, 2h, 3h, 5h, etc.), and the solid content of the solution is 40-70g / L (for example, 40g / L, 50g / L, 55g / L, 58g / L, 60g / L, 65g / L, 70g / L, etc.).

[0015] Further, in step B, a manganese precipitant and a citrate buffered saline solution are first configured into a precipitant solution, and then the second mixed solution is added to the precipitant solution; in the precipitant solution, the concentration of the manganese precipitant is 0.1-0.5 mol / L (for example, it can be 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, etc.), and the volume ratio of the precipitant solution to the first mixed solution is 0.3-0.6:1, for example, it can be 0.3:1, 0.4:1, 0.5:1, 0.6:1, etc.

[0016] Further, in step B, the temperature of the precipitation reaction is 15-30°C, for example, 15°C, 20°C, 25°C, 30°C, etc.

[0017] Further, in step C, the spray drying method specifically comprises the following steps:

[0018] (1) After the molar ratio of each metal ion in the third mixed solution meets the requirements, the third mixed solution is spray dried, and the feed rate is controlled to be 15-30 mL / min (for example, it can be 15 mL / min, 18 mL / min, 20 mL / min, 25 mL / min, 28 mL / min, 30 mL / min, etc.), the inlet temperature is 150-200°C (for example, it can be 150°C, 160°C, 180°C, 200°C, etc.), and the fan frequency is 30-100 Hz (for example, it can be 30 Hz, 50 Hz, 60 Hz, 70 Hz, 100 Hz, etc.), so as to obtain a precursor powder.

[0019] Furthermore, the present invention also includes a lithium battery, including a positive electrode sheet, a negative electrode sheet and a battery separator, wherein the positive electrode sheet is coated with a positive electrode material, wherein the positive electrode material is obtained by adding a lithium source to a positive electrode material precursor and co-firing the mixture, and wherein the positive electrode material precursor is prepared by the above method.

[0020] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0021] 1. Compared with inorganic acid, in the organic acid-reducing agent leaching system of the present invention, mild organic acid can not only ionize H + It can achieve the leaching of metal particles. At the same time, its own carboxyl group has a coordination effect and can become a good complexing agent, providing a better reaction environment for the subsequent precipitation of manganese, making up for the shortcomings of inorganic acid.

[0022] 2. In the present invention, under the condition of a stable pH value reaction environment, a part of the manganese ions in the leachate are first precipitated and recovered by a precipitation method, and then a part of the nickel ions are supplemented to regenerate the high-nickel positive electrode material. This method not only reduces the amount of metal ions added and reduces the recovery cost, but also the regenerated high-nickel positive electrode material precursor product has a higher added value, thereby increasing the profit margin of the enterprise;

[0023] 3. When the present invention uses a manganese precipitant to precipitate manganese ions, iron, aluminum, and copper metal ions are also precipitated at the same time, and the obtained high-nickel positive electrode material precursor has better quality;

[0024] 4. The method of the present invention has a simple process, effectively reduces the investment cost, does not produce secondary pollution, and the quality of the obtained recycled product is significantly improved, thus overcoming the shortcomings of the existing recycling and regeneration process. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0026] A method for regenerating and synthesizing a positive electrode material precursor using waste ternary lithium batteries comprises the following steps:

[0027] A. Pre-treating waste ternary lithium batteries to obtain positive electrode material powder, then leaching the positive electrode material powder using an organic acid-hydrogen peroxide system, and filtering to obtain a first mixed solution, wherein the concentration of the organic acid is 3-6 mol / L, the concentration of hydrogen peroxide is 10-25 vol%, the solid content of the solution is 40-80 g / L, the acid leaching temperature is 40-70° C., the acid leaching time is 1-5 h, and the organic acid is selected from one or more of citric acid, malic acid, and succinic acid;

[0028] B. adding a manganese ion sieve adsorbent to the first mixed solution, removing lithium ions and filtering to obtain a second mixed solution; wherein the manganese ion sieve adsorbent is preferably λ-MnO2 manganese ion sieve;

[0029] C. First, a manganese precipitant and a citrate buffer solution are configured into a precipitant solution, wherein the concentration of the manganese precipitant in the precipitant solution is 0.1-0.5 mol / L, and the pH value is 6.5-7.5, and then 1-5 wt% of 10% ammonia water is uniformly added to the second mixed solution, and then the second mixed solution is added to the precipitant solution and magnetically stirred, the volume ratio of the second mixed solution to the precipitant solution is 0.3-0.6:1, the temperature of the precipitation reaction is 15-30° C. After filtering the precipitate, a third mixed solution is obtained, wherein the manganese precipitant is one or more of ammonium oxalate and ammonium bicarbonate;

[0030] C. Take a small amount of the third mixed solution and perform ICP-OES elemental analysis on it to obtain the molar ratio of nickel, cobalt and manganese therein. According to the ICP-OES analysis, the molar ratio of nickel, cobalt and manganese is obtained, and then nickel and / or manganese are added to make the molar ratio of nickel ions, cobalt ions and manganese ions meet the product requirements of high-nickel positive electrode materials. Then, the second mixed solution is spray-dried, and the feed rate is controlled to be 15-30 mL / min, the inlet temperature is 150-200°C, and the fan frequency is 30-100 Hz to obtain a precursor powder.

[0031] Furthermore, in the above method, the pretreatment process of the waste ternary lithium battery includes: after the recycled waste ternary lithium battery is disassembled into battery cells, physical discharge is selected, and the discharge is completed when the battery voltage is lower than 0.5V. After the discharge is completed, the positive electrode plate is disassembled and separated, and the positive electrode plate is subjected to high-temperature calcination, generally first at 400°C for 2h, and then at 650°C for 4h, with a heating rate of 5°C / min. After calcination, the battery is cooled and the active substance detached from the positive electrode plate is collected to obtain the positive electrode material powder.

[0032] Further, in order to better illustrate the present invention, specific examples are listed below:

[0033] Example 1

[0034] S1. Dismantle the waste ternary lithium battery to obtain positive electrode material powder

[0035] The voltage of the single cell of the waste ternary lithium-ion battery was measured with a multimeter, and the lithium-ion battery was discharged by physical discharge to prevent spontaneous combustion caused by short circuit. The battery voltage was lower than 0.5V, which means the discharge was completed. Then the battery was manually disassembled, and the battery shell, negative electrode sheet, and diaphragm were recycled separately; the positive electrode sheet was placed in a muffle furnace for roasting, and the adhesive PVDF, conductive agent and other substances were removed by roasting. The roasting temperature was 650℃, and the temperature was programmed to be kept constant at 400℃ for 2h, and 650℃ for 4h, with a heating rate of 5℃ / min;

[0036] S2. Obtaining a first mixed solution

[0037] The calcined positive electrode sheet was taken out and gently shaken to remove it. The positive electrode material was peeled off from the current collector aluminum foil. 25 g of the positive electrode material was weighed, and the positive electrode material was ground through a 200-mesh sieve. The positive electrode material was dissolved in a citric acid-hydrogen peroxide system with a solid-liquid ratio of 60 g / L and 4 mol / L citric acid and 10 vol% hydrogen peroxide. The solution was heated to 60° C. in a water bath, leached for 4 h, and filtered to obtain a first mixed solution.

[0038] S3, obtaining a second mixed solution

[0039] Adding λ-MnO2 manganese ion sieve to the first mixed solution for selective adsorption, separating lithium ions from nickel, cobalt and manganese ions, and filtering to obtain a second mixed solution;

[0040] S4, obtaining a third mixed solution

[0041] A 0.5 mol / L (NH4)2C2O4 solution was prepared, and mixed with a citrate buffer solution to prepare a precipitant solution, the pH value was controlled to be 7.0, 1 wt% (relative to the second mixed solution, the same below) of 10% ammonia water was uniformly added dropwise into the second mixed solution, and the second mixed solution was uniformly added dropwise into the precipitant solution, the volume ratio of the second mixed solution to the precipitant solution was 1:0.38, the reaction temperature was 25°C, magnetic stirring was performed for 2 hours, and the precipitate was separated and collected by filtration to obtain a third mixed solution;

[0042] S5. Synthesis of high nickel cathode material precursor

[0043] (1) taking a portion of the third mixed solution and performing ICP-OES detection, the molar ratio of Ni:Co:Mn was obtained to be 3:1:1;

[0044] (2) According to the molar ratio of Ni:Co:Mn=8:1:1, add Ni(CH3COO)2 solution with a concentration of 1 mol / L, stir for 0.5 h and mix well;

[0045] (3) The third mixed solution was spray dried, and the feed rate was controlled to be 20 mL / min, the inlet temperature to be 200° C., and the fan frequency to be 60 Hz to obtain a precursor powder.

[0046] Example 2

[0047] Example 2 is the same as Example 1, except that step S3 of Example 2 is:

[0048] A 0.5 mol / L NH4HCO3 solution was prepared as a precipitant solution, and mixed with a citrate buffer solution to prepare a precipitant solution. The pH value was controlled to be 7.0. 1 wt% of 10% ammonia water was uniformly added dropwise into the second mixed solution. The second mixed solution was uniformly added dropwise into the precipitant solution. The volume ratio of the second mixed solution to the precipitant solution was 1:0.43. The reaction temperature was 25°C. The mixture was magnetically stirred for 2 hours. The precipitate was separated and collected by filtration to obtain a third mixed solution.

[0049] Step S5 of Example 2 is:

[0050] (1) taking a portion of the third mixed solution and performing ICP-OES detection, the molar ratio of Ni:Co:Mn was obtained to be 3:1:0.9;

[0051] (2) According to the molar ratio of Ni:Co:Mn=8:1:1, Ni(CH3COO)2 and Mn(CH3COO)3 solutions were added, the solution concentration was 1 mol / L, and stirred for 0.5 h to mix evenly;

[0052] (3) The third mixed solution was spray dried, and the feed rate was controlled to be 20 mL / min, the inlet temperature was 200° C., and the fan frequency was 60 Hz to obtain a precursor powder.

[0053] Example 3

[0054] Example 3 is the same as Example 1, except that step S4 of Example 3 is:

[0055] A 0.5 mol / L NH4HCO3 solution was prepared and mixed with a citrate buffer solution to prepare a precipitant solution. The pH value was controlled to be 7.0. 1 wt% of 10% ammonia water was uniformly added dropwise into the second mixed solution. The second mixed solution was uniformly added dropwise into the precipitant solution. The volume ratio of the second mixed solution to the precipitant solution was 1:0.4. The reaction temperature was 25°C. The mixture was magnetically stirred for 2 hours. The precipitate was separated and collected by filtration to obtain a third mixed solution.

[0056] Step S5 of Example 3 is:

[0057] (1) taking a portion of the third mixed solution and performing ICP-OES detection, the molar ratio of Ni:Co:Mn was obtained to be 3:1:0.95;

[0058] (2) According to the molar ratio of Ni:Co:Mn=8:1:1, Ni(CH3COO)2 and Mn(CH3COO)2 solutions were added, the solution concentration was 1 mol / L, and stirred for 0.5 h to mix evenly;

[0059] (3) The third mixed solution was spray dried, and the feed rate was controlled to be 20 mL / min, the inlet temperature was 200° C., and the fan frequency was 60 Hz to obtain a precursor powder.

[0060] Comparative Example 1

[0061] The comparative example is the same as Example 1, except that the second mixed solution obtained in Example 1 is taken, and then a high-nickel positive electrode material precursor is directly synthesized, and the specific steps are as follows:

[0062] (1) taking a portion of the second mixed solution and performing ICP-OES detection, the molar ratio of Ni:Co:Mn was obtained to be 3:1:2;

[0063] (2) According to the molar ratio of Ni:Co:Mn=8:1:1, Ni(NO3)2·6H2O and Mn(NO3)3·6H2O solutions were added, the solution concentration was 1 mol / L, and stirred for 0.5 h to mix evenly;

[0064] (3) The second mixed solution was spray dried, and the feed rate was controlled to be 20 mL / min, the inlet temperature was 200° C., and the fan frequency was 60 Hz to obtain a precursor powder.

[0065] Comparative Example 2

[0066] Comparative Example 2 is the same as Example 1, except that steps S4 and S5 of Comparative Example 2 are:

[0067] S4, obtaining a third mixed solution

[0068] Prepare 0.5 mol / L (NH4)2C2O4 as a precipitant solution, control the pH value to 7.0, uniformly add 1 wt% of 10% ammonia water into the second mixed solution, uniformly add the second mixed solution into the precipitant solution, the volume ratio of the second mixed solution to the precipitant solution is 1:0.38, the reaction temperature is 25°C, magnetic stirring is performed for 2 hours, and the precipitate is separated and collected by filtration to obtain a third mixed solution;

[0069] S5. Synthesis of high nickel cathode material precursor

[0070] (1) taking a portion of the third mixed solution and performing ICP-OES detection, the molar ratio of Ni:Co:Mn was obtained to be 2.5:0.9:1.5;

[0071] (2) According to the molar ratio of Ni:Co:Mn=8:1:1, add Ni(NO3)2·6H2O and Co(NO3)2·6H2O solution with a solution concentration of 1 mol / L, stir for 0.5 h and mix well;

[0072] (3) The second mixed solution was spray dried, and the feed rate was controlled to be 20 mL / min, the inlet temperature to be 200° C., and the fan frequency to be 60 Hz to obtain a precursor powder.

[0073] Comparative Example 3

[0074] Comparative Example 3 is the same as Example 1, except that steps S4 and S5 of Comparative Example 3 are:

[0075] Prepare 0.5 mol / L (NH4)2C2O4 as a precipitant solution, adjust the pH value to 7.0 with NaOH solution, uniformly add 1 wt% of 10% ammonia water into the second mixed solution, uniformly add the second mixed solution into the precipitant solution, the volume ratio of the second mixed solution to the precipitant solution is 1:0.38, the reaction temperature is 25°C, magnetic stirring is performed for 2 hours, and the precipitate is separated and collected by filtration to obtain a third mixed solution;

[0076] S4. Synthesis of high nickel cathode material precursor

[0077] (1) taking a portion of the third mixed solution and performing ICP-OES detection, the molar ratio of Ni:Co:Mn was obtained to be 2.3:0.9:1.6;

[0078] (2) According to the molar ratio of Ni:Co:Mn=8:1:1, add Ni(NO3)2·6H2O and Co(NO3)2·6H2O solution with a solution concentration of 1 mol / L, stir for 0.5 h and mix well;

[0079] (3) The third mixed solution was spray dried, and the feed rate was controlled to be 20 mL / min, the inlet temperature to be 200° C., and the fan frequency to be 60 Hz to obtain a precursor powder.

[0080] Test method:

[0081] Determination of iron, aluminum and copper contents: The contents of iron, aluminum and copper in the second mixed solution and the third mixed solution were analyzed by ICP-OES.

[0082] Preparation of pole piece: The obtained high nickel positive electrode material precursor is mixed with lithium and roasted to make positive electrode material, and then the obtained positive electrode material and conductive carbon black are placed in a mortar in a certain proportion, ground and mixed evenly, and then a certain amount of PVDF is added, positive electrode material: conductive carbon black: PVDF = 8:1:1. NMP is added to the mixed material, and after mixing, the mixed material is evenly coated on the current collector aluminum foil, and then placed in an oven for drying, and the positive pole piece is obtained after pressing and cutting.

[0083] Assemble the test battery: Use metallic lithium as the negative electrode and polypropylene microporous membrane as the separator, and assemble the button battery under the protection of inert gas.

[0084] Charge and discharge test: Use a battery tester to test the charge and discharge performance. Charge and discharge at 2.75-4.3V and 1C rate. After 50 cycles, test the discharge capacity.

[0085] Capacity retention rate = first discharge capacity / discharge capacity after 30 cycles*100.

[0086] The test results are shown in Table 1:

[0087] Table 1 Electrochemical performance of test cells assembled in Examples 1-3 and Comparative Examples 1-3

[0088]

[0089] From Table 1, we can get:

[0090] (1) By comparing Example 1 with Comparative Example 1, it can be found that when the second mixed solution is not subjected to the manganese partial precipitation treatment, the electrochemical performance of the lithium battery assembled in Comparative Example 1 is significantly reduced, especially the capacity retention rate, which declines significantly. This shows that in the recycled high-nickel positive electrode material precursor, the content of iron, aluminum and copper will affect its electrochemical performance, and reducing the content of iron, aluminum and copper is helpful to improve the electrochemical performance of the high-nickel positive electrode material;

[0091] (2) From the changes in the contents of iron, aluminum and copper in the second mixed solution and the third mixed solution of Examples 1-3, it can be concluded that the use of a manganese precipitant to partially precipitate manganese in the second mixed solution helps to reduce the contents of iron, aluminum and copper in the high-nickel positive electrode material, thereby helping to improve the electrochemical performance of the high-nickel positive electrode material.

[0092] (3) By comparing Example 1 with Comparative Example 2, it is found that when the citrate buffer solution is not added, the manganese ion precipitation effect is poor, and some nickel ions and cobalt ions are precipitated. The iron, aluminum and copper residues in the second mixed solution are relatively large, and the electrochemical performance of the obtained high-nickel positive electrode material is not as good as that of Examples 1-3 of the present invention;

[0093] (4) By comparing Example 1 with Comparative Example 3, it is found that when only the pH value of the precipitant solution is adjusted to the same, the manganese ion precipitation effect is still poor, and some nickel ions and cobalt ions are still precipitated. The residual iron, aluminum and copper in the second mixed solution is still large, and the electrochemical performance of the obtained high-nickel positive electrode material is not as good as that of Examples 1-3 of the present invention;

[0094] (5) As can be seen from Examples 1-3, the electrochemical performance of the high-nickel positive electrode material precursor regenerated by the method of the present invention meets the requirements of NCM811 finished products and can be directly sold as a product.

[0095] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for regenerating and synthesizing anode material precursors using waste ternary lithium batteries, characterized in that: The following steps are involved: A. Pre-treating waste ternary lithium batteries to obtain positive electrode material powder, then leaching the positive electrode material powder with an organic acid-hydrogen peroxide system, filtering to obtain a first mixed solution, adding a manganese ion sieve adsorbent to the first mixed solution, removing lithium ions and filtering to obtain a second mixed solution; the organic acid is selected from one or more of citric acid, malic acid, and succinic acid; B. First, a manganese precipitant and a citrate buffer solution are configured into a precipitant solution, wherein the concentration of the manganese precipitant in the precipitant solution is 0.1-0.5 mol / L, and the pH value is 6.5-7.

5. 10% ammonia water is uniformly added to the second mixed solution at a rate of 1-5 wt % relative to the second mixed solution, and then the second mixed solution is added to the precipitant solution, the volume ratio of the precipitant solution to the second mixed solution is 0.3-0.6:1, the temperature of the precipitation reaction is 15-35° C., and after the precipitation is filtered, a third mixed solution is obtained; the manganese precipitant is one or both of ammonium oxalate and ammonium bicarbonate; C. Analyze the molar ratio of each metal ion in the third mixed solution, and then add nickel ions and / or manganese ions to the third mixed solution so that the molar ratio of nickel ions, cobalt ions, and manganese ions meets the product requirements of high-nickel positive electrode materials, and then prepare a high-nickel positive electrode material precursor by spray drying.

2. The method according to claim 1, characterized in that In step A, the organic acid concentration is 3-6 mol / L, the hydrogen peroxide concentration is 10-25 vol%, the acid leaching temperature is 40-70° C., the acid leaching time is 1-5 h, and the solution solid content is 40-70 g / L.

3. The method according to claim 1, characterized in that In step C, the spray drying method specifically comprises the following steps: After the molar ratio of each metal ion in the third mixed solution meets the requirements, the third mixed solution is spray dried, and the feed rate is controlled to be 15-30 mL / min, the inlet temperature is 150-200° C., and the fan frequency is 30-100 Hz to obtain a precursor powder.

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