A method for preparing sodium-ion battery cathode materials from lithium-ion battery recycling materials

Abstract

The present invention discloses a method for preparing a sodium-ion battery cathode material from lithium-ion battery recycling materials, belonging to the field of battery technology. The method comprises the following steps: separating nickel and / or manganese contained in the lithium-ion battery recycling materials, and then preparing a precursor of the sodium-ion battery cathode material together with raw materials providing the remaining elements according to the elemental composition in the molecular formula of the preset sodium-ion battery cathode material. Further, the precursor of the sodium-ion battery cathode material is sintered and modified with a sodium source to obtain the sodium-ion battery cathode material. This method can greatly reduce the preparation cost of the sodium-ion battery cathode material and can form good resource recycling and green production.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular, to a method for preparing a sodium battery cathode material from lithium battery recycling materials. Background Art

[0002] In the global upsurge of new energy development, great progress has been made in the development of lithium batteries. However, rare metals such as lithium, nickel, and cobalt in the cathode materials of lithium batteries have a small global reserve, high mining costs, and large overall price fluctuations, bringing many challenges to the healthy development of the new energy market.

[0003] Since the biggest advantage of sodium-ion batteries compared to lithium-ion batteries is that they do not use precious metal lithium, the production cost has a great advantage. At present, the mainstream preparation process of sodium battery layered oxide cathode materials is the mixed calcination of sodium source and precursor, through doping, coating and other modification processes, and the precursor is mainly prepared by coprecipitation reaction of one or more of nickel sulfate, ferrous sulfate, manganese sulfate, copper sulfate, etc. As a precious metal, nickel sulfate is the main cost source of sodium battery cathode materials. For example, in the nickel-iron-manganese 111 system and the nickel-iron-manganese 244 system, the nickel cost accounts for about 60-75% of the total cost of precursor raw materials, and about 50%-60% of the total cost of cathode material raw materials. The source of nickel is the biggest obstacle restricting the cost reduction of sodium battery cathode materials, especially for manufacturers without upstream nickel ore and other resources, the cost pressure is greater.

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

[0005] The purpose of the present invention is to provide a method for preparing a sodium battery cathode material from lithium battery recycling materials to solve the above technical problems.

[0006] This application can be implemented as follows:

[0007] This application provides a method for preparing a sodium battery cathode material from lithium battery recycling materials, which includes the following steps: separating nickel and / or manganese contained in the lithium battery recycling materials, and then preparing a precursor of the sodium battery cathode material together with raw materials providing the remaining elements according to the element composition in the preset molecular formula of the sodium battery cathode material;

[0008] Sintering and modifying the precursor of the sodium battery cathode material with a sodium source to obtain the sodium battery cathode material.

[0009] In an alternative embodiment, the molecular formula of the lithium battery recycling material is Ni x Co y Mn z A 1-x-y-z (OH) 2 or Li 1+ a Ni x Coy Mn z A 1-x-y-z O 2 or Li 1+b Mn 2 B c O 4 At least one of them, where 0≤x≤1, 0≤y≤0.4, 0≤z≤0.5, 0≤a≤0.3, 0≤b≤0.3, 0≤c≤0.3, and A and B are independently selected from at least one of Al, Zr, Ti, Sr, Mg, W, Nb, B, Sn, Sb, Ta, Ba, Ce, Y, P, and F.

[0010] In an alternative embodiment, the lithium-ion battery recycling material includes at least one of a precursor recycling material of a lithium-ion battery cathode material, a lithium-ion battery cathode material recycling material, a lithium-ion battery electrode sheet recycling material, and a positive electrode recycling material disassembled from a power battery.

[0011] In an alternative embodiment, when the lithium-ion battery recycling material contains lithium, nickel, cobalt, and manganese at the same time, preparing a sodium-ion battery cathode material includes the following steps:

[0012] Subject the lithium-ion battery recycling material to high-temperature calcination, dissolve it in water, separate the solid and liquid to obtain a lithium-rich compound solution and a solid containing nickel, cobalt, and manganese;

[0013] Remove the remaining impurities other than nickel, cobalt, and manganese in the solid to obtain a first mixed solution rich in nickel, cobalt, and manganese;

[0014] Separate cobalt in the first mixed solution to obtain a cobalt-rich compound and a second mixed solution rich in nickel and manganese;

[0015] Prepare a sodium-ion battery cathode material precursor from the second mixed solution according to the elemental composition in the molecular formula of the preset sodium-ion battery cathode material.

[0016] In an alternative embodiment, the high-temperature calcination includes at least one of the following features:

[0017] Feature 1: The high-temperature calcination is a co-reaction of the lithium-ion battery recycling material and an additive;

[0018] Feature 2: The temperature of the high-temperature calcination is 200-900 °C;

[0019] Feature 3: The time of the high-temperature calcination is 1-10 h;

[0020] Feature 4: The high-temperature calcination is carried out in a ventilated atmosphere.

[0021] In an alternative embodiment, the additive includes at least one of sodium sulfite and a carbon source;

[0022] Or, the temperature of the high-temperature calcination is 200-750 °C;

[0023] Or, the high-temperature calcination time is 1 - 8 h;

[0024] Or, the ventilation atmosphere is a hydrogen atmosphere or a nitrogen atmosphere.

[0025] In an alternative embodiment, during the water dissolution process, the solid-liquid ratio of the lithium-ion battery recycling material to water is 1:2 - 5;

[0026] Or, the solid-liquid separation is carried out by centrifugation or pressure filtration.

[0027] In an alternative embodiment, during the water dissolution process, the solid-liquid ratio of the lithium-ion battery recycling material to water is 1:3;

[0028] Or, the equipment used for centrifugation is a centrifuge;

[0029] Or, the pressure filtration equipment used for pressure filtration includes a plate-and-frame filter press, a vertical filter press, or a washing filter press.

[0030] In an alternative embodiment, removing the remaining impurities other than nickel, cobalt, and manganese in the solid is achieved through a process including pickling with a reducing agent and impurity removal using an ion exchange resin;

[0031] Among them, the acid used for pickling includes at least one of sulfuric acid and hydrochloric acid;

[0032] Or, the reducing agent used for pickling includes H 2 O 2 ;

[0033] Or, the ion exchange resin used for impurity removal includes at least one of ZGA351, D840, D860, and T-62MP.

[0034] In an alternative embodiment, separating cobalt in the first mixed liquor is achieved through precipitation and extraction separation methods.

[0035] In an alternative embodiment, the precipitating agent used for precipitation includes at least one of ammonium oxalate, sodium oxalate, and sodium carbonate.

[0036] In an alternative embodiment, the molar ratio of oxalate or carbonate in the precipitating agent to cobalt is 1:1 - 1.5:1.

[0037] In an alternative embodiment, the precipitation process is carried out under the condition that the pH value is 7 - 12, preferably, the pH value is 9 - 12.

[0038] In an alternative embodiment, the pH value is adjusted by NaOH.

[0039] In an alternative embodiment, the extractant used in the extraction process includes at least one of Cyanex 272, Alamine 308, PC-88A, Versatic 10, and P507.

[0040] The beneficial effects of this application include:

[0041] By using lithium-ion battery recycling materials to prepare sodium-ion battery cathode materials, this application can achieve green recycling of resources, reduce environmental pollution caused by heavy metals such as nickel, cobalt, and manganese. In addition, high-value-added products such as lithium-rich (lithium carbonate) and cobalt-rich (cobalt sulfate) can be selectively separated according to the elemental composition of the recycling materials used, increasing profits. Preparing sodium-ion battery precursors from the nickel-manganese sulfate mother liquor in the recycling materials can greatly reduce the raw material cost of sodium-ion battery materials; moreover, this method can simplify the recycling process as needed, without separately separating products such as nickel and manganese, reducing the recycling cost. The water used in the recycling process can be recycled, reducing environmental pollution and achieving energy conservation and emission reduction. Description of the Drawings

[0042] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use 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 thus should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0043] Figure 1 It is a flowchart of the method for preparing sodium-ion battery cathode materials from lithium-ion battery recycling materials in Embodiment 1 of this application. Detailed Embodiments

[0044] 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. Those not specified in the embodiments are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or instruments not specified by the manufacturer are all conventional products that can be obtained through commercial purchase.

[0045] The method for preparing sodium-ion battery cathode materials from lithium-ion battery recycling materials provided in this application will be specifically described below.

[0046] This application proposes a method for preparing sodium-ion battery cathode materials from lithium-ion battery recycling materials, which includes the following steps: separating nickel and / or manganese contained in the lithium-ion battery recycling materials, and then jointly preparing a sodium-ion battery cathode material precursor with raw materials providing the remaining elements according to the elemental composition in the preset molecular formula of the sodium-ion battery cathode material; sintering and modifying the sodium-ion battery cathode material precursor with a sodium source to obtain the sodium-ion battery cathode material.

[0047] The molecular formula of the above lithium battery recycling material can exemplarily be Ni x Co y Mn z A 1-x-y-z (OH) 2 or Li 1+ a Ni x Co y Mn z A 1-x-y-z O 2 or Li 1+b Mn 2 B c O 4 and at least one of the following, where 0≤x≤1, 0≤y≤0.4, 0≤z≤0.5, 0≤a≤0.3, 0≤b≤0.3, 0≤c≤0.3, and A and B are independently selected from at least one of Al, Zr, Ti, Sr, Mg, W, Nb, B, Sn, Sb, Ta, Ba, Ce, Y, P, and F.

[0048] It should be noted that all lithium battery recycling materials that conform to the above molecular formula in this application are within the scope of protection of this application, and will not be listed one by one here.

[0049] For reference, the above lithium battery recycling material can, for example, include at least one of a lithium battery cathode material precursor recycling material, a lithium battery cathode material recycling material, a lithium battery electrode sheet recycling material, and a power battery disassembled cathode recycling material. In addition, it can also be any other form of lithium battery recycling material.

[0050] In this application, before separating Ni and / or Mn, according to the elements contained in the lithium battery recycling material, Li and Co contained therein are first recycled, and A and / or B can be selectively removed as needed. For example, when the lithium battery recycling material contains at least one of Li and Co, the above elements can be recycled separately to obtain corresponding value-added products, such as lithium carbonate or cobalt sulfate. When the lithium battery recycling material contains Ni but does not contain Mn, according to the element composition in the molecular formula of the sodium battery cathode material preset, the Ni-containing substance obtained by recycling can be jointly prepared with other iron salts and manganese salts to form a precursor of the sodium battery cathode material (in this process, if the recycled Ni is insufficient, new nickel salts can be added during the preparation of the precursor of the sodium battery cathode material). Similarly, when the lithium battery recycling material contains Mn but does not contain Ni, according to the element composition in the molecular formula of the sodium battery cathode material preset, the Mn-containing substance obtained by recycling can be jointly prepared with other iron salts and nickel salts to form a precursor of the sodium battery cathode material (in this process, if the recycled Mn is insufficient, new manganese salts can be added during the preparation of the precursor of the sodium battery cathode material). Similarly, if the lithium battery recycling material contains Mn and Ni, but the amount is not enough to prepare the precursor of the sodium battery cathode material, new manganese salts and nickel salts can be added on the basis of the Mn- and Ni-containing substances obtained by recycling).

[0051] In some embodiments, the lithium battery recycling material contains Li, Ni, Co, Mn, A, and B at the same time. The preparation of the sodium battery cathode material may include the following steps:

[0052] The lithium battery recycling material is subjected to high-temperature calcination, dissolved in water, and solid-liquid separated to obtain a lithium-rich compound solution and a solid containing nickel, cobalt, and manganese; the remaining impurities other than nickel, cobalt, and manganese in the solid are removed to obtain a first mixed solution rich in nickel, cobalt, and manganese; cobalt in the first mixed solution is separated to obtain a cobalt-rich compound and a second mixed solution rich in nickel and manganese; according to the element composition in the molecular formula of the sodium battery cathode material preset, the second mixed solution is prepared into a precursor of the sodium battery cathode material.

[0053] As a reference, the high-temperature calcination can be a reaction of the lithium battery recycling material with an additive. Among them, the additive is a reducing substance, and for example, it may include at least one of sodium sulfite and a carbon source (such as graphite, citric acid, or sucrose, etc.). The mass ratio of the lithium battery recycling material to the additive is 2-10:1, such as 2:1, 5:1, 8:1, or 10:1, etc.

[0054] The temperature of the high-temperature calcination can be 200-900 °C, such as 200 °C, 250 °C, 300 °C, 350 °C, 400 °C, 450 °C, 500 °C, 550 °C, 600 °C, 650 °C, 700 °C, 750 °C, 800 °C, 850 °C, or 900 °C, etc., or any other value within the range of 200-900 °C, and preferably 200-750 °C.

[0055] The high-temperature calcination time can be 1 - 10 h, such as 1 h, 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h, 5 h, 5.5 h, 6 h, 6.5 h, 7 h, 7.5 h, 8 h, 8.5 h, 9 h, 9.5 h or 10 h, etc., or can be any other arbitrary value within the range of 1 - 10 h, preferably 1 - 8 h.

[0056] The above high-temperature calcination is carried out in a vented atmosphere. Exemplarily, the vented atmosphere can be a hydrogen atmosphere or a nitrogen atmosphere.

[0057] Furthermore, the calcined product after high-temperature calcination is mixed with water to dissolve Li in the calcined product. For reference, during the process of adding water for dissolution, the solid-liquid ratio of the lithium-ion battery recycling material to water can be 1:2 - 5, such as 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5 or 1:5, etc., or can be any other arbitrary value within the range of 1:2 - 5, preferably 1:3.

[0058] After dissolution, solid-liquid separation is carried out. The solid-liquid separation can be carried out by centrifugation or pressure filtration. Exemplarily, the equipment used for centrifugation can be a centrifuge, and the pressure filtration equipment used for pressure filtration can include a plate-and-frame filter press, a vertical filter press or a washing filter press.

[0059] The liquid obtained after separation is a lithium-rich compound solution. The solid obtained after separation contains Ni, Co, Mn, and may also contain A and / or B corresponding to the molecular formula.

[0060] In some embodiments, the lithium-rich compound solution can be subjected to evaporation crystallization to finally obtain lithium carbonate.

[0061] It should be noted that the above process and method for preparing lithium carbonate from the lithium-rich compound solution can also refer to any other existing technologies that can achieve this result, and no excessive limitation is imposed on it here.

[0062] Furthermore, A and / or B and other possible impurities in the solid containing Ni, Co, Mn, and possibly containing A and / or B corresponding to the molecular formula are removed.

[0063] Exemplarily, this process can be achieved through processes such as pickling with a reducing agent and impurity removal by ion exchange resin, so as to remove impurities such as copper, aluminum, and iron, and obtain a mixed salt solution rich in nickel, cobalt, and manganese (i.e., the first mixed material liquid).

[0064] During the above process of obtaining the mixed salt solution rich in nickel, cobalt, and manganese, the acid used for pickling can include, for example, at least one of sulfuric acid and hydrochloric acid, and its molar ratio to the metal (nickel, cobalt, manganese) can be 1.5 - 2.0:1, preferably 1.5 - 1.8:1, such as 1.5:1, 1.6:1, 1.7:1 or 1.8:1, etc.

[0065] The reducing agent used in pickling includes H 2 O 2 , and the molar ratio of the acid to the reducing agent can be 3.0 - 4.0:1, such as 3:1, 3.5:1 or 4:1, etc.

[0066] The ion exchange resins used for impurity removal include at least one of ZGA351, D840, D860 and T-62MP.

[0067] In some optional embodiments, the first mixed solution rich in nickel, cobalt and manganese can be separated by processes such as precipitation and extraction to obtain a high-value cobalt sulfate product.

[0068] The precipitating agent used for precipitation can include, for example, at least one of ammonium oxalate, sodium oxalate and sodium carbonate; the molar ratio of oxalate or carbonate radical in the precipitating agent to cobalt is 1 - 1.5:1, such as 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1 or 1.5:1, etc.

[0069] The precipitation process can be carried out under the condition that the pH value is 7 - 12. In some preferred embodiments, the precipitation process is carried out under the condition that the pH value is 9 - 12.

[0070] The above pH value can be adjusted by NaOH, and the concentration of NaOH can be exemplarily 2 mol / L.

[0071] The extractants used in the extraction process can include, for example, at least one of Cyanex 272, Alamine 308, PC-88A, Versatic 10 and P507. The main parameters for cobalt extraction include: the temperature is 25 - 45 °C (such as 25 °C, 30 °C, 35 °C, 40 °C or 45 °C, etc.), the concentration of the extractant is 0.2 - 0.8 mol / L (such as 0.2 mol / L, 0.4 mol / L, 0.6 mol / L or 0.8 mol / L, etc.), the O / A ratio is 1 - 2:1 (such as 1:1, 1.5:1 or 2:1, etc.), and the pH value is 2 - 6 (such as 2, 3, 4, 5 or 6, etc.).

[0072] It should be noted that the above process and method for separating cobalt from the first mixed solution rich in nickel, cobalt and manganese can also refer to any other existing technologies that can achieve the same result, and no excessive limitation is made here.

[0073] Furthermore, the second mixed solution rich in nickel and manganese obtained after separating cobalt from the first mixed solution is prepared into a precursor of the sodium-ion battery cathode material. In this process, other required substances (such as a mixed metal salt solution prepared from sulfates of nickel, iron, manganese, etc.) can be added according to the elemental composition and molar ratio in the molecular formula of the preset sodium-ion battery cathode material, and then it is prepared according to the co-precipitation method.

[0074] It should be noted that the specific process and conditions for preparing the precursor by the coprecipitation method can refer to the corresponding existing technologies, and will not be limited and elaborated here.

[0075] In addition, when some elements of Li, A, Ni, Co, and Mn are not contained in the lithium-ion battery recycling material, the corresponding steps can be omitted accordingly with reference to the above process.

[0076] Furthermore, the obtained sodium-ion battery cathode material precursor is sintered and modified with a sodium source to obtain a sodium-ion battery cathode material.

[0077] For reference, the sodium source may include, for example, at least one of sodium carbonate, sodium hydroxide, sodium bicarbonate, and sodium citrate.

[0078] The dosage relationship between the sodium-ion battery cathode material precursor and the sodium source can be: the molar ratio of the metal in the sodium-ion battery cathode material to sodium in the sodium source is 1:0.6 - 1.1, such as 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, or 1:1.1, etc.

[0079] The sintering temperature can be 700 - 1100 °C (such as 700 °C, 800 °C, 900 °C, 1000 °C, or 1100 °C, etc.), the sintering time can be 8 - 20 h (such as 8 h, 10 h, 12 h, 15 h, 18 h, or 20 h, etc.), and the sintering atmosphere can be air, oxygen, or a mixture of air and oxygen.

[0080] The modification method can be in the form of bulk doping or surface coating, etc. Specifically, which method to adopt and which doping material or coating material to use, etc., can be carried out according to needs with reference to relevant existing technologies.

[0081] Continuing from the above, this application proposes to separate high-value-added materials such as lithium and cobalt from recycling materials containing main elements such as lithium, nickel, cobalt, and manganese, including but not limited to ternary cathode materials, ternary precursors, and ternary lithium battery recycling materials, retain the nickel-manganese sulfate mother liquor, use the nickel-manganese sulfate mother liquor as the main raw material for the sodium-ion battery precursor, add sulfates such as nickel, iron, manganese, and copper to the mother liquor in a designed proportion and add a measured amount of pure water to stir and dissolve to obtain a mixed salt solution, and prepare a precursor for the sodium-ion battery cathode material through a coprecipitation reaction. This method has at least the following advantages:

[0082] (1) Extracting high-value-added products such as lithium-rich (lithium carbonate) and cobalt-rich (cobalt sulfate) from the recycling material increases profits, and using the nickel-manganese sulfate mother liquor in the recycling material as the raw material to prepare the sodium-ion battery precursor greatly reduces the raw material cost;

[0083] (2) Preparing the precursor from the recycling material and then preparing the cathode material can achieve green recycling of resources and reduce environmental pollution by heavy metals such as nickel, cobalt, and manganese;

[0084] (3) The recycling process flow can be simplified as needed, without separately separating products such as nickel and manganese, reducing the recycling cost.

[0085] The features and performance of the present invention will be further described in detail below in conjunction with embodiments.

[0086] Embodiment 1

[0087] This embodiment provides a method for preparing a sodium - ion battery cathode material from a lithium - ion battery recycling material. Please refer to Figure 1 , which includes the following steps:

[0088] S1: Using a lithium - ion battery ternary cathode material recycling material with the molecular formula LiNi 0.83 Co 0.12 Mn 0.05 O 2 as the raw material to be processed, calcining it in a hydrogen atmosphere at 500 °C for 2 h to obtain a calcined product.

[0089] S2: Mix the calcined product with water at a solid - liquid ratio of 1:3, and then filter it using a plate - and - frame filter press to obtain a lithium - rich compound solution and a solid containing Ni, Co, and Mn.

[0090] S3: Evaporate and crystallize the lithium - rich compound to recover the obtained lithium carbonate.

[0091] S4: Acid - wash and remove impurities using ion - exchange resins for the solid containing Ni, Co, and Mn to remove impurities such as copper, aluminum, and iron, obtaining a mixed salt solution rich in nickel, cobalt, and manganese (i.e., the first mixed material solution). In this process, the acid used for acid - washing is sulfuric acid, and the molar ratio of sulfuric acid to the metal (nickel, cobalt, manganese) is 1.5:1; the reducing agent added during acid - washing is H 2 O 2 , and the molar ratio of sulfuric acid to H 2 O 2 is 3.5:1. The impurity removal is carried out by two - stage adsorption using D860 ion - exchange resin and T - 62MP ion - exchange resin in sequence.

[0092] S5: Carry out precipitation and extraction separation on the first mixed material solution to recover the obtained cobalt sulfate.

[0093] The precipitating agent used in this process is sodium oxalate. The pH value is adjusted to 11 by 2 mol / L NaOH during the precipitation process. The molar ratio of oxalate in sodium oxalate to cobalt in cobalt sulfate is 1.2:1. The filtrate after precipitation is extracted with 0.5 mol / L Cyanex 272 as the extractant at 25 °C under the conditions of O / A = 1.5 and pH = 4 to extract cobalt.

[0094] S6: Add the element composition (NaNi 1 / 3 Fe 1 / 3 Mn 1 / 3 O 2 ) and molar ratio in the molecular formula of the preset sodium-ion battery cathode material of the second mixed solution rich in nickel and manganese to the corresponding other required metal salt solutions (NiSO 4 ·6H 2 O, FeSO 4 ·7H 2 O and MnSO 4 ·H 2 O), and prepare the precursor of the sodium-ion battery cathode material (Ni 1 / 3 Fe 1 / 3 Mn 1 / 3 (OH) 2 ) according to the co-precipitation method.

[0095] S7: Mix sodium carbonate and the precursor of the sodium-ion battery cathode material according to a molar ratio of Na to metal of 1.04, add 1 wt% of ZrO as a dopant and mix. Under an air atmosphere, sinter at 1060 °C for 18 h to obtain a first-fired material.

[0096] S8: Use H 3 BO 3 with a mass fraction of 1.5% of the first-fired material as a coating agent and mix. Keep warm at 450 °C for 10 h to obtain the sodium-ion battery cathode material.

[0097] Example 2

[0098] The difference between this example and Example 1 is that in S1, the high-temperature calcination temperature is 200 °C, the high-temperature calcination time is 10 h, and the high-temperature calcination is carried out in a nitrogen atmosphere.

[0099] Example 3

[0100] The difference between this example and Example 1 is that in S1, the high-temperature calcination temperature is 750 °C, and the high-temperature calcination time is 8 h.

[0101] Example 4

[0102] The difference between this example and Example 1 is that in S1, the high-temperature calcination temperature is 900 °C, and the high-temperature calcination time is 1 h.

[0103] Example 5

[0104] The difference between this example and Example 1 is that in S5, the precipitation is carried out under the condition of a pH value of 2.

[0105] Example 6

[0106] The difference between this embodiment and Embodiment 1 is that in S5, the precipitation is carried out under the condition that the pH value is 6.

[0107] Embodiment 7

[0108] The difference between this embodiment and Embodiment 1 is that the lithium-ion battery recycling material is a recycling material of the precursor of the lithium-ion battery cathode material, and its molecular formula is Ni 0.50 Co 0.20 Mn 0.30 (OH) 2 , and the corresponding S3 step is not included.

[0109] Embodiment 8

[0110] The difference between this embodiment and Embodiment 1 is that the lithium-ion battery recycling material is a recycling material of the lithium-ion battery electrode sheet, and its molecular formula is LiNi 0.55 Co 0.15 Mn 0.30 O 2 , and the corresponding S4 step is not included.

[0111] Embodiment 9

[0112] The difference between this embodiment and Embodiment 1 is that the lithium-ion battery recycling material is a recycling material of the lithium-ion battery cathode material, and its molecular formula is LiMn 2 O 4 , and the corresponding S5 step is not included.

[0113] Embodiment 10

[0114] The difference between this embodiment and Embodiment 1 is that the lithium-ion battery recycling material is a recycling material of the lithium-ion battery cathode material, and its molecular formula is LiNi 0.88 Co 0.09 Al 0.03 O 2 , and correspondingly, a manganese sulfate or ferrous sulfate solution is added in S6.

[0115] In summary, this application uses mature lithium-ion battery recycling materials as the raw material source to provide a new idea for preparing sodium-ion battery cathode materials at low cost. This solution can greatly reduce the cost of sodium-ion battery cathode materials and can form good resource recycling and green production. Specifically, its advantages include:

[0116] (1) Separating high-value-added material recycling materials such as lithium and cobalt from recycling materials containing main elements such as lithium, nickel, cobalt, and manganese, such as lithium-ion battery ternary cathode materials, ternary precursors, and lithium-ion battery cathode material recycling materials, retaining the nickel-manganese sulfate mother liquor, and then adding sulfates such as nickel, iron, and manganese to prepare a mixed salt solution for sodium-ion battery precursors. The sodium-ion battery precursor is prepared by the coprecipitation method, and then the sodium-ion battery cathode material is prepared, reducing the raw material cost in the precursor coprecipitation reaction, realizing the recycling of resources, forming an industrial chain closed loop, reducing heavy metal pollution, and increasing the added value;

[0117] (2) Simplifies the recycling process of recycled materials, shortens the process flow, reduces the consumption of raw materials such as acids and alkalis, and overall reduces the recycling cost;

[0118] (3) Selectively recycles high-value-added products such as lithium and cobalt, increasing profits;

[0119] (4) The water in the recycling process is recycled, reducing environmental pollution and achieving energy conservation and emission reduction.

[0120] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a sodium-ion battery cathode material from lithium-ion battery recycling materials, characterized in that, The molecular formula of the lithium-ion battery recycling material is Li 1+a Ni x Co y Mn z A 1-x-y-z O 2 , where 0 ≤ x ≤ 1, 0 ≤ y ≤ 0.4, 0 ≤ z ≤ 0.5, 0 ≤ a ≤ 0.3, and A is selected from at least one of Al, Zr, Ti, Sr, Mg, W, Nb, B, Sn, Sb, Ta, Ba, Ce, Y, P, and F; the preparation of the sodium-ion battery cathode material includes the following steps: subjecting the lithium-ion battery recycling materials to high-temperature calcination, dissolving in water, separating the solid from the liquid to obtain a lithium-rich compound solution and a solid containing nickel, cobalt, and manganese; removing other impurities in the solid except nickel, cobalt, and manganese to obtain a first mixed solution rich in nickel, cobalt, and manganese; separating cobalt from the first mixed solution to obtain a cobalt-rich compound and a second mixed solution rich in nickel and manganese; the separation of cobalt from the first mixed solution is achieved by precipitation and extraction separation methods; the precipitating agent used in precipitation includes at least one of ammonium oxalate, sodium oxalate, and sodium carbonate; the extractant used in the extraction process includes at least one of Cyanex 272, Alamine308, PC-88A, Versatic 10, and P507; adding other required metal salts according to the elemental composition in the molecular formula of the preset sodium-ion battery cathode material, and preparing the second mixed solution into a precursor of the sodium-ion battery cathode material; the high-temperature calcination is to react the lithium-ion battery recycling materials with an additive; the temperature of the high-temperature calcination is 200-900 °C; the time of the high-temperature calcination is 1-10 h; the high-temperature calcination is carried out in a ventilated atmosphere; the additive includes at least one of sodium sulfite and a carbon source.

2. The method according to claim 1, characterized in that, the lithium-ion battery recycling materials include at least one of a precursor recycling material of a lithium-ion battery cathode material, a lithium-ion battery cathode material recycling material, a lithium-ion battery electrode sheet recycling material, and a positive electrode recycling material obtained by disassembling a power battery.

3. The method according to claim 1, characterized in that, the temperature of the high-temperature calcination is 200-750 °C; or, the time of the high-temperature calcination is 1-8 h; or, the ventilated atmosphere is a hydrogen atmosphere or a nitrogen atmosphere.

4. The method according to claim 1, characterized in that, during the water dissolution process, the solid-liquid ratio of the lithium-ion battery recycling materials to water is 1:2-5; or, the solid-liquid separation is carried out by centrifugation or pressure filtration.

5. The method according to claim 4, characterized in that, during the water dissolution process, the solid-liquid ratio of the lithium-ion battery recycling materials to water is 1:3; or, the equipment used for centrifugation is a centrifuge; or, the pressure filtration equipment used for pressure filtration includes a plate and frame filter press, a vertical filter press, or a washing filter press.

6. The method according to claim 1, characterized in that, removing other impurities in the solid except nickel, cobalt, and manganese is achieved by a process including adding a reducing agent for pickling and removing impurities with an ion exchange resin; wherein, the acid used for pickling includes at least one of sulfuric acid and hydrochloric acid; Or, the reducing agent used for pickling includes H 2 O 2 ; or, the ion exchange resin used for removing impurities includes at least one of ZGA351, D840, and D860.

7. The method according to claim 1, characterized in that, the molar ratio of oxalate or carbonate in the precipitating agent to cobalt is 1-1.5:

1.

8. The method according to claim 1, characterized in that, the precipitation process is carried out under the condition of a pH value of 7-12.

9. The method according to claim 8, characterized in that, the precipitation process is carried out under the condition of a pH value of 9-12.

10. The method according to claim 8, wherein, the pH value is adjusted by NaOH.

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