Impurity removing and repairing method for waste ternary material and ternary positive electrode material

Abstract

The invention discloses an impurity removal and repair method of a waste ternary material and a ternary positive electrode material, the impurity removal and repair method of the waste ternary material comprises the following steps: separating waste residue and waste powder after crushing a waste ternary pole piece to obtain black powder, and mixing the waste ternary pole piece with lithium iron phosphate pole piece impurities; the black powder is heated in an oxygen-containing atmosphere, the heating temperature ranges from 350 DEG C to 550 DEG C, and the heating time ranges from 0.1 min to 180 min; removing magnetic impurities from the heated black powder through a magnetic separator; sequentially carrying out alkali washing, water washing and drying on the black powder from which the magnetic impurities are removed; detecting the lithium content in the dried powder, and uniformly mixing a lithium source according to the missing amount; and sintering the dry powder mixed with the lithium source at high temperature. The method comprises the following steps: removing conductive carbon, a high-molecular binder, metallic aluminum and carelessly introduced lithium iron phosphate and other impurities in the waste ternary pole piece one by one to obtain a pure ternary positive electrode material, and supplementing lithium into the material to restore the performance of the damaged ternary waste material.

Description

Technical Field

[0001] This invention relates to the field of lithium battery recycling technology, and more specifically, to a method for removing impurities and repairing waste ternary materials and ternary cathode materials. Background Technology

[0002] With the rapid development of the new energy vehicle industry, the amount of retired power batteries has experienced explosive growth. Lithium iron phosphate (LiFePO4) and ternary lithium (Ni-Co-Mn) batteries, as two mainstream cathode materials for power batteries, have attracted widespread attention for their recycling technologies. Among existing technologies, relatively mature process routes have been developed for the recycling of lithium iron phosphate batteries, including the oxidation roasting and selective leaching technology proposed in CN119725837A, which can achieve graded recycling of lithium, iron, phosphorus, and graphite; and the NMP waste liquid recycling and treatment method developed in CN115557872A, which achieves solid-phase regeneration of spent lithium iron phosphate electrodes through heat treatment, improving resource utilization. In addition, traditional processes such as hydrometallurgy and pyrometallurgy can also effectively address the recycling problem of single-type battery materials.

[0003] However, in actual recycling scenarios, waste batteries often contain a mixture of various cathode materials. Especially with the increasing use of lithium iron phosphate (LFP) batteries, impurities from LFP electrode sheets are inevitably introduced during the recycling of ternary lithium-ion batteries. While existing processes focused on ternary lithium-ion battery recycling can efficiently process a single material, they lack targeted methods for separating impurities from other cathode materials within the ternary lithium-ion battery. When processing waste batteries containing small amounts of LFP electrode sheet impurities from ternary cathode materials, these methods struggle to achieve efficient separation and purification of the components, leading to decreased purity of the recycled products and reduced resource utilization.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a method for removing impurities and repairing waste ternary materials and ternary cathode materials, aiming to solve the problem of waste batteries with a small amount of LFP in the ternary cathode material, and the problem of magnetic foreign matter that may be introduced during the impurity removal process.

[0006] This invention is implemented as follows: In a first aspect, the present invention provides a method for removing impurities and repairing waste ternary materials, which includes the following steps: The waste residue and waste powder after crushing the waste ternary electrode sheets are separated to obtain black powder. The waste ternary electrode sheets contain lithium iron phosphate electrode sheet impurities. Ternary means that the active material contains any three or more of the four metals nickel, cobalt, manganese and aluminum. The black powder was heated in an oxygen-containing atmosphere at a temperature of 350~550℃ for a time of 0.1min~180min. The heated black powder is then passed through a magnetic separator to remove magnetic impurities. After removing magnetic impurities, the black powder is sequentially washed with alkali, washed with water, and dried. The lithium content in the dried powder was detected, and a lithium source was added according to the amount of missing lithium. The dried powder mixed with lithium source is sintered at high temperature.

[0007] In an optional implementation, the waste ternary electrode comes from ternary electrode that has not been injected with liquid or electrode that has already been injected with liquid, and the mass of the impurities introduced into the lithium iron phosphate electrode is <5%.

[0008] In an optional embodiment, the waste residue and the waste powder are separated by a sieve with a mesh size of 200 to 600.

[0009] In an optional embodiment, the black powder is heated at a temperature of 350°C to 450°C in an oxygen-containing atmosphere for a heating time of 20 to 60 minutes.

[0010] And / or, the oxygen content of the oxygen-containing atmosphere is 20% to 100%.

[0011] In an optional embodiment, the magnetic separator has a magnetic strength of 5000~15000 Gauss.

[0012] In an optional embodiment, the alkaline solution used for alkaline washing is selected from sodium hydroxide solution, potassium hydroxide solution or ammonium hydroxide solution, wherein the pH of the alkaline solution is greater than 12, and the mass of the alkaline solution is 1 to 5 times the mass of the black powder.

[0013] In an optional embodiment, the lithium source is selected from one or more of lithium hydroxide or lithium carbonate, and the amount of lithium source added is controlled according to the following target value: the molar ratio of lithium element to transition metal element in the material satisfies 1≤n(Li) / n(transition metal)≤1.15 (where n(Li) is the amount of lithium and n(transition metal) is the total amount of transition metal).

[0014] In an optional embodiment, the high-temperature sintering temperature is 700℃~900℃, and the sintering time is 0.1h~14h.

[0015] In an optional embodiment, high-temperature sintering is carried out in an oxygen-containing sintering atmosphere, wherein the oxygen content of the sintering atmosphere is 20% to 100%.

[0016] Secondly, the present invention provides a ternary cathode material, which is obtained by the method for removing impurities and repairing waste ternary materials described in any of the foregoing embodiments.

[0017] This invention offers the following advantages: It employs a multi-step impurity removal process to systematically remove inherent impurities such as conductive carbon, polymer binders, and metallic aluminum from waste ternary electrode sheets. Furthermore, it effectively separates exogenous impurities such as lithium iron phosphate through oxygen-containing heat treatment and magnetic separation under specific conditions, ultimately obtaining high-purity ternary cathode material components. Based on this, lithium supplementation and heat treatment processes repair and reconstruct the material's crystal structure, restoring the electrochemical performance of the waste ternary material. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 The first charge-discharge curve of the positive electrode material in Example 1; Figure 2 The first charge-discharge curve of the positive electrode material in Example 2; Figure 3 The first charge-discharge curve of the positive electrode material in Example 3; Figure 4 The first charge-discharge curves of the cathode material in Comparative Example 1 are shown. Figure 5 The first charge-discharge curves of the cathode material in Comparative Example 2 are shown. Figure 6 The first charge-discharge curves of the cathode material in Comparative Example 3 are shown. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0021] The following is a detailed description of a method for removing impurities and repairing waste ternary materials provided by the present invention, as well as the ternary cathode material.

[0022] Some embodiments of the present invention provide a method for removing impurities and repairing waste ternary materials, which includes the following steps: The waste residue and waste powder after crushing the waste ternary electrode sheets are separated to obtain black powder, wherein the waste ternary electrode sheets are mixed with lithium iron phosphate electrode sheet impurities. The black powder was heated in an oxygen-containing atmosphere at a temperature of 350~550℃ for a time of 0.1min~180min. The heated black powder is then passed through a magnetic separator to remove magnetic impurities. After removing magnetic impurities, the black powder is sequentially washed with alkali, washed with water, and dried. The lithium content in the dried powder was detected, and a lithium source was added according to the amount of missing lithium. The dried powder mixed with lithium source is sintered at high temperature.

[0023] By using specific heat treatment conditions, the divalent iron in lithium iron phosphate (LFP) is oxidized to trivalent iron, and then LFP impurities are effectively removed by magnetic separation while retaining the ternary material. This achieves deep impurity removal and efficient repair and utilization of waste ternary materials, solving the problem in existing technologies that cannot effectively separate and repair ternary cathode materials with exogenous impurities such as lithium iron phosphate.

[0024] Specifically, in some implementation methods, the method for removing impurities and repairing waste ternary materials includes the following steps: S1. Place the waste ternary electrode sheets into a pulverizer and crush them to obtain waste residue and waste powder.

[0025] The coating is peeled off from the current collector (e.g., aluminum foil) using the friction and impact of a shredder.

[0026] Specifically, in some implementations, the waste ternary electrode sheets come from ternary electrode sheets that have not been injected with liquid or have already been injected with liquid, and the mass of impurities introduced from the lithium iron phosphate electrode sheets is <5%. If the impurity content of lithium iron phosphate is too high, some of the impurities such as iron tetroxide generated during the subsequent oxidation heating process will be combined with black powder and cannot be separated.

[0027] S2. Use a sieve to separate the waste residue and waste powder to obtain black powder.

[0028] In some embodiments, the mesh size of the sieve is 200-600 mesh. After the positive electrode material is crushed, the particle size of impurities such as current collector debris (aluminum foil, copper foil) is larger (usually >100μm). This separation step can remove large aluminum particles from the powder.

[0029] S3. Place the black powder in the kiln and heat it in an oxygen-containing atmosphere.

[0030] Specifically, the heating temperature is 350~550℃, such as 350℃, 370℃, 390℃, 400℃, 420℃, 450℃, 480℃, 500℃, 530℃ or 550℃, or a temperature between any two of the above temperatures, and the heating time is 0.1min~180min, such as 20min, 30min, 40min, 50min, 60min, 70min, 80min, 90min or 100min, or a time between any two of the above times.

[0031] Specifically, the mass percentages of impurities introduced into the lithium iron phosphate electrode are: 0.001%, 0.002%, 0.003%, 0.004%, 0.005%, 0.006%, 0.007%, 0.008%, 0.009%, 0.010%, 0.015%, 0.020%, 0.025%, 0.030%, 0.035%, 0.040%, 0.045%, 0.050%, 0.060%, 0.070%, 0.080%, 0.090%, 0.10%, 0.15%, 0.20%, 0.25%, 0.30%, 0.40%, 0.50%, and 0.60%. 0.70%, 0.80%, 0.90%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3.0%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, 4.0%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, 4.6%, 4.7%, 4.8%, 4.9%, 5%.

[0032] It should be noted that conducting the reaction within a temperature range of 350–550℃ and a reaction time range of 0.1–180 minutes can effectively crack polyvinylidene fluoride (PVDF) impurities while simultaneously promoting the complete oxidation of lithium iron phosphate into magnetic magnetite (Fe3O4). This specific selection of temperature and time parameters ensures, on the one hand, the complete conversion of lithium iron phosphate to magnetite, thus facilitating the subsequent magnetic separation process; on the other hand, it avoids over-oxidation (generating weakly magnetic ferric oxide) caused by excessively high temperatures or reaction times, or prevents the lithium iron phosphate from binding with ternary materials under high-temperature conditions, which could affect the separation effect.

[0033] Furthermore, in order to achieve better impurity separation, the reaction temperature and reaction time were optimized. In some embodiments, the black powder was heated at a temperature of 350°C to 500°C in an oxygen-containing atmosphere for a heating time of 20 to 60 minutes.

[0034] In some implementations, the oxygen content of the oxygen-containing atmosphere is 20% to 100%.

[0035] S4. Pass the heated black powder through a magnetic separator to remove magnetic impurities (iron oxide impurities and magnetic foreign matter from the oxidation of lithium iron phosphate).

[0036] In some implementations, the magnetic field strength of the magnetic separator is 5000~15000 Gauss, for example 6000 Gauss.

[0037] S5. After removing magnetic impurities, the black powder is washed with alkali, washed with water, and dried in sequence.

[0038] Specifically, the alkaline solution used for alkaline washing includes, but is not limited to, sodium hydroxide solution, potassium hydroxide solution or ammonium hydroxide solution. The pH of the alkaline solution is greater than 12, and the mass of the alkaline solution is 1 to 5 times the mass of the black powder.

[0039] Thorough washing of the black powder with an alkaline solution can dissolve the small amount of unseparated Al metal present in the black powder.

[0040] S6. Detect the lithium content in the dried powder and mix in the lithium source evenly according to the missing amount.

[0041] In some embodiments, the lithium source includes, but is not limited to, one or more mixtures of lithium hydroxide or lithium carbonate, and the amount of lithium source supplemented is such that the molar ratio of lithium to transition metal in the material is 1 to 1.15.

[0042] S7. The dry powder mixed with lithium source is sintered at high temperature.

[0043] Specifically, high-temperature sintering is carried out in a heating furnace. High-temperature sintering can remove carbon impurities and complete lithium replenishment.

[0044] In some embodiments, the high-temperature sintering temperature is 700℃~900℃. For example, the sintering temperature can be selected as 700℃, 710℃, 720℃, 730℃, 740℃, 750℃, 760℃, 770℃, 780℃, 790℃, 800℃, 810℃, 820℃, 830℃, 840℃, 850℃, 860℃, 870℃, 880℃, 890℃, or 900℃, or a temperature between any two of the above temperatures. The sintering time is 0.1h~14h. For example, it can be 0.1h, 0.5h, 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h, 13h, or 14h, or a time between any two of the above times.

[0045] In some embodiments, high-temperature sintering is carried out in an oxygen-containing sintering atmosphere, with an oxygen content of 20% to 100%. Carbon impurities (such as residual binders, conductive agents, and organic byproducts) undergo combustion reactions at high temperatures in the oxygen-containing atmosphere (air, oxygen) and are discharged in gaseous form. The oxygen-containing atmosphere can maintain the oxidation environment of the system, avoid the reduction and decomposition of the lithium source at high temperatures, ensure that the lithium replenishment agent participates efficiently in the lattice repair reaction, and improve the lithium-ion intercalation / deintercalation capability.

[0046] Furthermore, some embodiments of the present invention also provide a ternary cathode material, which is obtained by the impurity removal and repair method of waste ternary materials described in any of the foregoing embodiments.

[0047] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0048] Example 1 This embodiment provides a method for removing impurities and repairing waste ternary materials, which includes the following steps: (1) Use a pulverizer to pulverize the positive electrode of the waste battery and pass it through a 300-mesh sieve to obtain positive electrode black powder. The ratio of ternary to lithium iron phosphate in the positive electrode is 97:3.

[0049] (2) Take 1 kg of black powder and put it into a heating furnace with an air atmosphere, and keep it at 350℃ for 30 min.

[0050] (3) Use an electromagnetic iron remover to treat the heat-treated black powder with a magnetic field strength of 8000 Gauss.

[0051] (4) The demagnetized black powder was added to 4 kg of NaOH solution with pH=14 and stirred for 30 min. The slurry was then filtered to obtain filter cake I.

[0052] (5) Add filter cake I to 4 kg of pure water and stir for 30 min, then filter to obtain filter cake II.

[0053] (6) Place filter cake II in an 80℃ oven and dry for 12 hours.

[0054] (7) Detect the molar ratio of Li, Ni, Co and Mn in the dried powder.

[0055] (8) Based on the component detection data, use a mixer to uniformly mix the powder with LiOH·H2O, and control the target value of the added LiOH·H2O so that the molar ratio of Li to transition metal in the mixed powder is 1.04.

[0056] (9) Place the mixed powder in a heating furnace and heat it at 850°C for 10 hours in an air atmosphere to obtain a pure ternary repair material.

[0057] Example 2 This embodiment provides a method for removing impurities and repairing waste ternary materials, which includes the following steps: (1) Use a pulverizer to pulverize the positive electrode of the waste battery and pass it through a 300-mesh sieve to obtain positive electrode black powder. The ratio of ternary to lithium iron phosphate in the positive electrode is 97:3.

[0058] (2) Take 1 kg of black powder and put it into a heating furnace with an air atmosphere, and keep it at 550℃ for 30 min.

[0059] (3) Use an electromagnetic iron remover to treat the heat-treated black powder with a magnetic field strength of 8000 Gauss.

[0060] (4) The demagnetized black powder was added to 4 kg of NaOH solution with pH=14 and stirred for 30 min. The slurry was then filtered to obtain filter cake I.

[0061] (5) Add filter cake I to 4 kg of pure water and stir for 30 min, then filter to obtain filter cake II.

[0062] (6) Place filter cake II in an 80℃ oven and dry for 12 hours.

[0063] (7) Detect the molar ratio of Li, Ni, Co and Mn in the dried powder.

[0064] (8) Based on the component detection data, use a mixer to uniformly mix the powder with LiOH·H2O, and control the target value of the added LiOH·H2O so that the molar ratio of Li to transition metal in the mixed powder is 1.04.

[0065] (9) Place the mixed powder in a heating furnace and heat it at 850°C for 10 hours in an air atmosphere to obtain a pure ternary repair material.

[0066] Example 3 This embodiment provides a method for removing impurities and repairing waste ternary materials, which includes the following steps: (1) Use a pulverizer to pulverize the positive electrode of the waste battery and pass it through a 300-mesh sieve to obtain positive electrode black powder. The ratio of ternary to lithium iron phosphate in the positive electrode is 97:3.

[0067] (2) Take 1 kg of black powder and put it into a heating furnace with an air atmosphere, and keep it at 350℃ for 180 min.

[0068] (3) Use an electromagnetic iron remover to treat the heat-treated black powder with a magnetic field strength of 8000 Gauss.

[0069] (4) The demagnetized black powder was added to 4 kg of NaOH solution with pH=14 and stirred for 30 min. The slurry was then filtered to obtain filter cake I.

[0070] (5) Add filter cake I to 4 kg of pure water and stir for 30 min, then filter to obtain filter cake II.

[0071] (6) Place filter cake II in an 80℃ oven and dry for 12 hours.

[0072] (7) Detect the molar ratio of Li, Ni, Co and Mn in the dried powder.

[0073] (8) Based on the component detection data, use a mixer to uniformly mix the powder with LiOH·H2O, and control the target value of the added LiOH·H2O so that the molar ratio of Li to transition metal in the mixed powder is 1.04.

[0074] (9) Place the mixed powder in a heating furnace and heat it at 850°C for 10 hours in an air atmosphere to obtain a pure ternary repair material.

[0075] Comparative Example 1 This comparative example provides a method for removing impurities and repairing and utilizing waste ternary materials, which includes the following steps: (1) Use a pulverizer to pulverize the positive electrode of the waste battery and pass it through a 300-mesh sieve to obtain positive electrode black powder. The ratio of ternary to lithium iron phosphate in the positive electrode is 97:3.

[0076] (2) Take 1 kg of black powder and put it into a heating furnace with an air atmosphere, and keep it at 350℃ for 60 min.

[0077] (3) The heated black powder was added to 4 kg of NaOH solution with pH=14 and stirred for 30 min. The slurry was then filtered to obtain filter cake I.

[0078] (4) Add filter cake I to 4 kg of pure water and stir for 30 min, then filter to obtain filter cake II.

[0079] (5) Place filter cake II in an 80℃ oven and dry for 12 hours.

[0080] (6) Detect the molar ratio of Li, Ni, Co and Mn in the dried powder.

[0081] (7) Based on the component detection data, use a mixer to uniformly mix the powder with LiOH·H2O, and control the amount of the target value of added LiOH·H2O so that the molar ratio of Li to transition metal in the mixed powder is 1.04.

[0082] (8) Place the mixed powder in a heating furnace and heat it at 850°C for 10 hours in an air atmosphere to obtain a pure ternary repair material.

[0083] The ternary cathode materials obtained from the examples and comparative examples were subjected to performance testing.

[0084] Comparative Example 2 This embodiment provides a method for removing impurities and repairing waste ternary materials, which includes the following steps: (1) Use a pulverizer to pulverize the positive electrode of the waste battery and pass it through a 300-mesh sieve to obtain positive electrode black powder. The ratio of ternary to lithium iron phosphate in the positive electrode is 97:3.

[0085] (2) Take 1 kg of black powder and put it into a heating furnace with an air atmosphere, and keep it at 650℃ for 30 min.

[0086] (3) Use an electromagnetic iron remover to treat the heat-treated black powder with a magnetic field strength of 8000 Gauss.

[0087] (4) The demagnetized black powder was added to 4 kg of NaOH solution with pH=14 and stirred for 30 min. The slurry was then filtered to obtain filter cake I.

[0088] (5) Add filter cake I to 4 kg of pure water and stir for 30 min, then filter to obtain filter cake II.

[0089] (6) Place filter cake II in an 80℃ oven and dry for 12 hours.

[0090] (7) Detect the molar ratio of Li, Ni, Co and Mn in the dried powder.

[0091] (8) Based on the component detection data, use a mixer to uniformly mix the powder with LiOH·H2O, and control the target value of the added LiOH·H2O so that the molar ratio of Li to transition metal in the mixed powder is 1.04.

[0092] (9) Place the mixed powder in a heating furnace and heat it at 850°C for 10 hours in an air atmosphere to obtain a pure ternary repair material.

[0093] Comparative Example 3 This embodiment provides a method for removing impurities and repairing waste ternary materials, which includes the following steps: (1) Use a pulverizer to pulverize the positive electrode of the waste battery and pass it through a 300-mesh sieve to obtain positive electrode black powder. The ratio of ternary to lithium iron phosphate in the positive electrode is 97:3.

[0094] (2) Take 1 kg of black powder and put it into a heating furnace with an air atmosphere, and keep it at 350℃ for 280 min.

[0095] (3) Use an electromagnetic iron remover to treat the heat-treated black powder with a magnetic field strength of 8000 Gauss.

[0096] (4) The demagnetized black powder was added to 4 kg of NaOH solution with pH=14 and stirred for 30 min. The slurry was then filtered to obtain filter cake I.

[0097] (5) Add filter cake I to 4 kg of pure water and stir for 30 min, then filter to obtain filter cake II.

[0098] (6) Place filter cake II in an 80℃ oven and dry for 12 hours.

[0099] (7) Detect the molar ratio of Li, Ni, Co and Mn in the dried powder.

[0100] (8) Based on the component detection data, use a mixer to uniformly mix the powder with LiOH·H2O, and control the target value of the added LiOH·H2O so that the molar ratio of Li to transition metal in the mixed powder is 1.04.

[0101] (9) Place the mixed powder in a heating furnace and heat it at 850°C for 10 hours in an air atmosphere to obtain a pure ternary repair material.

[0102] Capacity testing method: The specific capacity of the positive electrode material was tested using a coin cell. First, the positive electrode material, SP, and PVDF were mixed in a 90:5:5 ratio, and then an appropriate amount of NMP was added and shaken to obtain a uniform black slurry. Next, the slurry was coated onto aluminum foil using a coating machine and dried at 105°C. Then, the dried electrode sheet was compacted using a roller press and cut into circular pieces to obtain the battery positive electrode. Finally, the battery positive electrode, separator, lithium foil, and electrolyte were assembled sequentially into a coin cell casing to obtain a coin cell for capacity testing. The test conditions were 25°C, 0.1C charging + 0.1C discharging.

[0103] Iron content testing method: The iron content in the material is tested using ICP. First, weigh 1g of sample and dissolve it in 10mL of concentrated hydrochloric acid. After heating at 180℃ for 20min, dilute to 100mL with pure water to obtain a pretreatment solution. Then, test the pretreatment solution using an ICP instrument and read the iron content.

[0104] The test results are as follows:

[0105] In summary, the embodiments of the present invention remove conductive carbon, polymer binders, metallic aluminum, and lithium iron phosphate, which may be accidentally introduced, from waste ternary electrode sheets through a multi-step impurity removal process. This achieves deep impurity removal and efficient repair and utilization of waste ternary materials, solving the problem in the prior art that it is impossible to effectively separate and repair mixtures of various cathode materials.

[0106] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for removing impurities and repairing waste ternary materials, characterized in that, It comprises the following steps: The waste residue and waste powder after crushing the waste and old ternary pole piece are separated to obtain black powder, wherein the waste and old ternary pole piece is mixed with lithium iron phosphate pole piece impurities; The black powder is heated in an oxygen-containing atmosphere, the heating temperature is 350-550℃, and the heating time is 0.1min-180min; The heated black powder is removed from the magnetic impurities by a magnetic separator; The black powder after removing the magnetic impurities is sequentially washed with alkali, washed with water, and dried; The lithium content in the dried powder is detected, and lithium source is mixed according to the missing amount; The dried powder mixed with lithium source is high-temperature sintered.

2. The impurity removal and restoration method of the spent ternary material according to claim 1, characterized by, The mass of lithium iron phosphate pole piece impurities introduced by the waste and old ternary pole piece is <5%.

3. The impurity removal and restoration method of the spent ternary material according to claim 1, characterized by, The waste residue and the waste powder are separated by a screen, and the mesh number of the screen is 200-600.

4. The impurity removal and restoration method of the spent ternary material according to claim 1, characterized by, The temperature for heating the black powder in the oxygen-containing atmosphere is 350-450℃, and the heating time is 20-60min. And / or, the oxygen content of the oxygen-containing atmosphere is 20%-100%.

5. The method according to any one of claims 1 to 4, wherein the method is characterized by, The magnetic field strength of the magnetic separator is 5000-15000 Gauss.

6. The method according to any one of claims 1 to 4, wherein the method is characterized by, The alkaline solution used for alkali washing is selected from any one or more of sodium hydroxide solution, potassium hydroxide solution, or lithium hydroxide, barium hydroxide solution, the pH of the alkaline solution is >12, and the mass of the alkaline solution is 1-5 times the mass of the black powder.

7. The method according to any one of claims 1 to 4, wherein the method is a method for removing impurities from waste and old ternary materials. The lithium source is selected from one or more of lithium hydroxide or lithium carbonate, and the addition amount of the lithium source is controlled according to the following target value: the molar ratio of lithium element to transition metal element in the material satisfies 1≤n(Li) / n(transition metal)≤1.15 (wherein n(Li) is the amount of substance of lithium, and n(transition metal) is the total amount of substance of transition metal).

8. The method according to any one of claims 1 to 4, wherein the method is a method for removing impurities from waste and old ternary materials. The temperature for high-temperature sintering is 700-900℃, and the sintering time is 0.1h-14h.

9. The method according to any one of claims 1 to 4, wherein the method is a method for removing impurities from waste and old ternary materials. The high-temperature sintering is carried out in an oxygen-containing sintering atmosphere, and the oxygen content of the sintering atmosphere is 20%-100%.

10. A ternary cathode material, characterized in that, It is obtained by the impurity removal and repair method of the waste and old ternary material according to any one of claims 1-9.

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