Recycling methods for lithium metal batteries

Abstract

The present application discloses a method for recycling lithium metal batteries, relating to the field of lithium battery recycling technology. The method comprises: providing battery waste, wherein the battery waste contains lithium metal; mixing the battery waste with a lithiation-capable substrate, and obtaining a first lithium-containing solution after solid-liquid separation, wherein the first lithium-containing solution contains an organic lithium compound; adding a powder to be lithiated to the first lithium-containing solution, and obtaining a lithium-rich powder after solid-liquid separation; acid-leaching the lithium-rich powder to obtain a second lithium-containing solution; and adding a lithium precipitating agent to the second lithium-containing solution to obtain a lithium salt. The recycling process of the lithium metal batteries of the present application does not involve violent reactions, and the process is simple and highly safe.

Description

Technical Field

[0001] The present application relates to the technical field of lithium battery recycling, and in particular to a method for recycling metal lithium batteries. Background Art

[0002] With the rapid development of the lithium battery market, lithium metal batteries have become a popular choice for next-generation high-energy-density batteries due to their high energy density (theoretical capacity up to 3860 mAh / g) and low electrode potential (-3.04 V vs. SHE). However, the high activity of metallic lithium also poses significant safety risks and recycling challenges. During battery cycling, lithium dendrites are easily formed on the metallic lithium anode. These dendrites can pierce the separator, causing battery short circuits and even thermal runaway, which in turn generates flammable gases such as hydrogen, increasing the risk of explosion. In addition, side reactions between metallic lithium and the electrolyte continuously consume lithium and electrolyte, leading to capacity decay and shortened battery life.

[0003] At present, the recycling technology of metallic lithium negative electrodes is still in the exploratory stage. The main difficulty lies in that metallic lithium can easily react with air or moisture during the recycling process to generate hydrogen, which increases operational risks. Conventional recycling methods are usually energy-intensive and costly.

[0004] The above content is only used to assist in understanding the technical solution of this application and does not constitute an admission that the above content is prior art. Summary of the Invention

[0005] The main purpose of this application is to provide a method for recycling metal lithium batteries, which has no violent reaction during the recycling process and is simple and safe.

[0006] To achieve the above objectives, the present application proposes a method for recycling metal lithium batteries, the method comprising:

[0007] Providing battery waste, wherein the battery waste contains metallic lithium;

[0008] Mixing the battery waste with a lithiation-capable substrate, and obtaining a first lithium-containing solution after solid-liquid separation, wherein the first lithium-containing solution contains an organic lithium compound;

[0009] Adding the powder to be lithiated to the first lithium-containing solution, and obtaining lithium-rich powder after solid-liquid separation;

[0010] acid leaching the lithium-rich powder to obtain a second lithium-containing solution;

[0011] A lithium precipitating agent is added to the second lithium-containing solution to obtain a lithium salt.

[0012] In one embodiment, the lithiation-capable substrate includes aromatic hydrocarbons.

[0013] In one embodiment, the amount of the lithiatable substrate added is 1.2 to 1.5 times the molar amount of lithium in the battery waste.

[0014] In one embodiment, the step of mixing the battery waste with a lithiation-capable substrate comprises:

[0015] mixing a lithiation-capable substrate with a first solvent to obtain a lithiation-capable substrate solution, wherein the first solvent is the same as the electrolyte contained in the battery waste;

[0016] The lithiatable substrate solution is mixed with the battery waste.

[0017] In one embodiment, the powder to be lithiated includes at least one of silicon powder, graphite powder, hard carbon powder and silicon-carbon powder.

[0018] In one embodiment, the molar amount of lithium that can be absorbed by the powder to be lithiated is 1.2 to 1.5 times the molar amount of lithium in the battery waste.

[0019] In one embodiment, the leaching agent used in the acid leaching includes: at least one of sulfuric acid and hydrochloric acid;

[0020] and / or, the hydrogen ion concentration of the leaching agent used in the acid leaching is 1 to 4 mol / L;

[0021] And / or, the leaching temperature of the acid leaching is 50-95°C.

[0022] In one embodiment, after the step of acid leaching the lithium-rich powder, the method further comprises:

[0023] Solid-liquid separation to obtain lithium-free powder;

[0024] The delithiated powder is used as the powder to be lithiated.

[0025] In one embodiment, the lithium precipitating agent includes at least one of sodium carbonate, sodium phosphate and sodium fluoride.

[0026] In one embodiment, the step of adding a lithium precipitating agent to the second lithium-containing solution comprises:

[0027] Control the pH to 9~11 and the reaction temperature to 50~95℃.

[0028] One or more technical solutions proposed in this application have at least the following technical effects: by mixing battery waste containing metallic lithium with a lithiation-capable substrate; using the lithiation-capable substrate to absorb metallic lithium and convert it into a soluble organic lithium compound to obtain a first lithium-containing solution; then adding the powder to be lithiated to the first lithium-containing solution, obtaining a lithium-rich powder after solid-liquid separation; then acid-leaching the lithium-rich powder to leach lithium ions to obtain a second lithium-containing solution, and adding a lithium precipitator to the second lithium-containing solution to obtain a high-purity lithium salt. The recovery process of the embodiment of the present application does not involve violent reactions, the process is simple and safe, and high-purity lithium salts can be directly separated and recovered. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0030] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0031] Figure 1 A schematic diagram of a process flow diagram of Example 1 of the recycling method for lithium metal batteries of the present application;

[0032] Figure 2 This is a flow chart of a relatively complete embodiment of the recycling method of metal lithium batteries of the present application.

[0033] The purpose, features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0034] To make the purpose, technical solutions and advantages of the examples of the present application clearer, the technical solutions in the examples of the present application will be described clearly and completely below. Where specific conditions are not specified in the examples, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially.

[0035] Below, embodiments of the metal lithium battery recycling method disclosed herein are described in detail, with appropriate reference to the accompanying drawings. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repeated descriptions of substantially identical structures may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0036] The "range" disclosed in this application is defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of a particular range. The range defined in this way can be inclusive or exclusive of the end values, and can be arbitrarily combined, i.e., any lower limit can be combined with any upper limit to form a range. For example, if a range of 60 to 120 and 80 to 110 is listed for a particular parameter, it is understood that a range of 60 to 110 and 80 to 120 is also expected. In addition, if the minimum range values ​​listed are 1 and 2, and if the maximum range values ​​listed are 3, 4, and 5, then the following ranges can all be expected: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4, and 2 to 5. In this application, unless otherwise specified, the numerical range "a to b" represents an abbreviation of any real number combination between a and b, wherein a and b are both real numbers. For example, a numerical range of "0-5" indicates that all real numbers between "0-5" are listed herein, and "0-5" is simply an abbreviation for these numerical combinations. Furthermore, stating that a parameter is an integer ≥ 2 is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0037] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0038] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0039] Unless otherwise specified, all steps of the present application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), indicating that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0040] Unless otherwise specified, the terms "include" and "comprising" used in this application may be open-ended or closed-ended. For example, "include" and "comprising" may mean that other components not listed may also be included or that only the listed components are included.

[0041] Unless otherwise specified, the term "or" is used in this application to be inclusive. For example, the phrase "A or B" means "A, B, or both A and B." More specifically, the condition "A or B" is satisfied if any of the following conditions are met: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0042] To make the above-mentioned objects, features and advantages of the present application more clearly understood, the technical solutions of the present application are further described below with reference to the accompanying drawings and embodiments. However, the present application is not limited to the embodiments listed, but also includes any other known modifications within the scope of the rights claimed in the present application.

[0043] The term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present application. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0044] In order to better understand the technical solution of the present application, a detailed description will be given below in conjunction with the accompanying drawings and specific implementation methods.

[0045] Conventional recycling techniques for lithium metal batteries are relatively limited and complex. For example, physical disassembly requires strictly controlled environmental conditions to avoid moisture contact. While high-temperature smelting can effectively recover some valuable metals, it consumes a lot of energy and may produce harmful gases. Hydrometallurgy requires the use of large amounts of chemical reagents and is costly. Furthermore, during the recycling process, metallic lithium easily reacts with air or moisture, generating hydrogen, which increases operational risks.

[0046] The present application provides a solution, which involves mixing battery waste containing metallic lithium with a lithiation-capable substrate; utilizing the lithiation-capable substrate to absorb metallic lithium and convert it into a soluble organic lithium compound to obtain a first lithium-containing solution; then adding the powder to be lithiated to the first lithium-containing solution, and obtaining a lithium-rich powder after solid-liquid separation; then subjecting the lithium-rich powder to acid leaching to leach lithium ions to obtain a second lithium-containing solution, and adding a lithium precipitator to the second lithium-containing solution to obtain a high-purity lithium salt. The recovery process of the present application embodiment does not involve a violent reaction, and the process is simple and safe, while also allowing for direct separation and recovery of high-purity lithium salts.

[0047] Based on this, the present invention provides a method for recycling lithium metal batteries. Figure 1 , Figure 1 This is a flow chart of the first embodiment of the recycling method for lithium metal batteries of the present application. In this embodiment, the recycling method for lithium metal batteries includes:

[0048] Step S10, providing battery waste, wherein the battery waste contains metallic lithium;

[0049] In one feasible embodiment, metallic lithium batteries may be crushed to obtain battery waste containing metallic lithium.

[0050] Lithium metal batteries typically use lithium metal as the negative electrode. These batteries utilize the efficient intercalation and deintercalation of lithium metal during the charge and discharge process, enabling energy storage and release. Lithium metal batteries have attracted considerable attention due to their high energy density and lightweight design.

[0051] Exemplarily, waste batteries are crushed under an inert atmosphere to obtain battery waste containing metallic lithium.

[0052] Step S20, mixing the battery waste with a lithiation-capable substrate, and obtaining a first lithium-containing solution after solid-liquid separation, wherein the first lithium-containing solution contains an organic lithium compound;

[0053] In one feasible embodiment, the battery waste is mixed with a lithiation-capable substrate, and the lithiation-capable substrate is used to absorb metallic lithium and convert it into a soluble organic lithium compound. Then, through solid-liquid separation, a first lithium-containing solution containing the organic lithium compound and a battery mixture are obtained.

[0054] In one possible embodiment, step S20, the step of mixing the battery waste with the lithiation-capable substrate comprises:

[0055] Step S21, mixing a lithiation-capable substrate with a first solvent to obtain a lithiation-capable substrate solution, wherein the first solvent is the same as the electrolyte contained in the battery waste;

[0056] Step S22: mixing the lithiation-capable substrate solution with the battery waste.

[0057] In one embodiment, a lithiatable substrate can be first mixed with a first solvent to obtain a lithiatable substrate solution. The lithiatable substrate solution is then mixed with the battery waste to allow the metallic lithium to fully react with the lithiatable substrate. The first solvent can be the same as the electrolyte contained in the battery waste to avoid the introduction of new impurities.

[0058] Optionally, the first solvent is the same as the metal lithium battery electrolyte and can be separated by distillation.

[0059] Optionally, the first solvent includes: an ether solvent and / or an ester solvent.

[0060] Exemplarily, the first solvent includes at least one of dimethoxyethane (DME), ethyl methyl carbonate (EMC), and 1,3-dioxolane (DOL).

[0061] In one possible embodiment, the lithiation-capable substrate includes aromatic hydrocarbons.

[0062] Aromatic hydrocarbons can absorb metallic lithium and convert it into soluble organolithium compounds. This reaction can provide an effective method to treat highly reactive metallic lithium and convert it into a more stable and easy-to-handle form.

[0063] Exemplarily, the lithiatable substrate includes at least one of naphthalene, anthracene, and biphenyl.

[0064] Compared to benzene, naphthalene is more reactive and can more readily undergo lithiation reactions. The resulting naphthyllithium is also an important intermediate in organic synthesis. Due to its high basicity and nucleophilicity, naphthyllithium performs well in certain types of organic reactions.

[0065] Anthracene is a polycyclic aromatic hydrocarbon with a higher degree of conjugation than benzene and naphthalene. This allows it to react with metallic lithium to form anthracenthion, a reagent particularly suitable for certain selective organic synthesis reactions. Due to its unique electronic structure, anthracenthion exhibits unique reactivity, such as the ability to selectively lithiate specific sites in certain situations.

[0066] Although not as commonly used as the aforementioned aromatic hydrocarbons, biphenyl can also react with metallic lithium to form lithium biphenyl under appropriate conditions. Biphenyl and its derivatives exhibit unique advantages under certain conditions due to their rigidity and significant steric hindrance.

[0067] In one possible embodiment, the amount of the lithiatable substrate added is 1.2 to 1.5 times the molar amount of lithium in the battery waste. For example, the amount of the lithiatable substrate added is 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5, etc., of the molar amount of lithium in the battery waste.

[0068] In the process of reacting aromatic hydrocarbons with metallic lithium to form organolithium compounds, the amount of substrate added is crucial to the success of the reaction. When the amount of aromatic hydrocarbon added is too high, it may first lead to a decrease in cost-effectiveness, because the excess aromatic hydrocarbon not only wastes raw materials but also increases the complexity and cost of subsequent processing steps. Secondly, excessive aromatic hydrocarbons may lead to the formation of unnecessary by-products. In addition, in some cases, excessive aromatic hydrocarbons may affect the solubility or fluidity of the reaction system, especially when non-polar solvents are used, which further affects the reaction efficiency and product purity. Conversely, when the amount of aromatic hydrocarbon added is insufficient, the main problem is that the metallic lithium may not be completely converted into the organolithium compound. The unreacted metallic lithium residue not only reduces the yield of the target product but also poses a safety hazard, because metallic lithium is very active and easily reacts violently with moisture in the air, even causing fire or explosion. Incomplete conversion of metallic lithium also means that there may be a risk of local overheating in the reaction system, which is particularly dangerous in large-scale production processes. The amount of lithium absorbed by the lithiation substrate (for example, aromatic hydrocarbon) is one lithium ion per molecule. Therefore, the embodiment of the present application determines that the amount of the lithiation substrate added is 1.2 to 1.5 times the molar amount of lithium in the battery waste.

[0069] Step S30, adding the powder to be lithiated to the first lithium-containing solution, and obtaining lithium-rich powder after solid-liquid separation;

[0070] In one feasible embodiment, powder to be lithiated is further added to the first lithium-containing solution, and the powder to be lithiated adsorbs lithium ions to form lithium-rich powder, which is then separated into lithium-rich powder and a mixed solution.

[0071] Exemplarily, the powder to be lithiated is added to the first lithium-containing solution, and the solution is stirred at a rotation speed of 20-100 r / min to adsorb lithium ions to form lithium-rich powder.

[0072] In one feasible embodiment, the powder to be lithiated includes at least one of silicon powder, graphite powder, hard carbon powder and silicon-carbon powder.

[0073] In one feasible embodiment, the molar amount of lithium that can be absorbed by the powder to be lithiated is 1.2 to 1.5 times the molar amount of lithium in the battery waste. For example, the molar amount of lithium that can be absorbed by the powder to be lithiated is 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5, etc., of the molar amount of lithium in the battery waste.

[0074] In the process of using a lithiated powder to adsorb lithium ions from a solution to form a lithium-rich powder, the amount of lithiated powder added plays a crucial role in the final result. Excessive addition of lithiated powder increases costs and may waste resources. Furthermore, excessive adsorbent can lead to excessively high viscosity in the reaction system or difficulty in solid-liquid separation. This is particularly true when using materials such as silicon, which, due to its large specific surface area and potential tendency to agglomerate, can result in uneven dispersion, thus affecting the effective adsorption efficiency of lithium ions. Furthermore, subsequent processing steps, such as filtration and washing, become more complex, increasing operational difficulty and energy consumption. Conversely, insufficient lithiated powder addition may result in insufficient adsorption capacity, resulting in a reduced lithium recovery rate. Furthermore, because different lithiated powders have different densities and can absorb varying amounts of metallic lithium, the present embodiment sets the molar amount of lithium that can be absorbed by the lithiated powder to 1.2 to 1.5 times the molar amount of lithium in the battery waste to control the amount of lithiated powder added.

[0075] Optionally, the obtained mixed solution can be added to the mixture during the process of mixing the battery waste and the lithiation substrate; or after the distillation treatment, the specific solvent can be separated and used as the first solvent.

[0076] Step S40, acid leaching the lithium-rich powder to obtain a second lithium-containing solution;

[0077] In one feasible embodiment, a leaching agent is added, and the lithium-rich powder is acid-leached at 50-95° C. with auxiliary stirring at a speed of 100-300 r / min to leach lithium ions, and solid-liquid separation is performed to obtain a second lithium-containing solution and a lithium-depleted powder.

[0078] Optionally, the hydrogen ion concentration of the leaching agent used in acid leaching is 1 to 4 mol / L; for example, the hydrogen ion concentration of the leaching agent used in acid leaching is 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L, 3 mol / L, 3.5 mol / L, 4 mol / L, etc.

[0079] Optionally, the leaching agent used in the acid leaching includes at least one of sulfuric acid and hydrochloric acid.

[0080] Optionally, the leaching temperature of the acid leaching can be: 50°C, 60°C, 70°C, 80°C, 90°C, 95°C, etc.

[0081] In one feasible embodiment, after the step of acid leaching the lithium-rich powder in step S40, the method further includes:

[0082] Step S41, solid-liquid separation to obtain lithium-free powder;

[0083] Step S42: using the delithiated powder as the powder to be lithiated.

[0084] In a feasible embodiment, a second lithium-containing solution and a lithium-depleted powder can be obtained after acid leaching, and the lithium-depleted powder can be reused as a powder to be lithiated, thereby achieving efficient utilization of resources.

[0085] Step S50: adding a lithium precipitating agent to the second lithium-containing solution to obtain a lithium salt.

[0086] In one feasible embodiment, a lithium precipitating agent is added to the second lithium-containing solution, the pH is controlled to be 9-11, the reaction temperature is 50-95°C, and stirring is assisted at a speed of 100-300 r / min to obtain a lithium salt precipitate. After solid-liquid separation, the lithium element is safely and efficiently recovered.

[0087] Optionally, the lithium precipitating agent includes at least one of sodium carbonate, sodium phosphate and sodium fluoride.

[0088] Alternatively, the pH may be 9, 10, 11, etc.

[0089] Optionally, the reaction temperature can be: 50°C, 60°C, 70°C, 80°C, 90°C, 95°C, etc.

[0090] In this embodiment, battery waste containing metallic lithium is mixed with a lithiation-capable substrate; the lithiation-capable substrate absorbs metallic lithium and converts it into a soluble organic lithium compound to obtain a first lithium-containing solution; the powder to be lithiated is then added to the first lithium-containing solution, and a lithium-rich powder is obtained after solid-liquid separation; the lithium-rich powder is then acid-leached to leach lithium ions to obtain a second lithium-containing solution, and a lithium precipitator is added to the second lithium-containing solution to obtain a high-purity lithium salt. The recovery process of the embodiment of the present application does not involve violent reactions, the process is simple and safe, and high-purity lithium salts can be directly separated and recovered.

[0091] To assist in understanding the above technical solution, the following is a more complete example of a method for recycling metal lithium batteries. Figure 2 , providing waste metal lithium batteries, crushing the batteries under an inert atmosphere to obtain battery waste containing metal lithium. Providing a lithiation-capable substrate solution and mixing it with the battery waste, utilizing the lithiation-capable substrate to absorb metal lithium and convert it into a soluble organic lithium compound, performing solid-liquid separation to obtain a first lithium-containing solution and a battery mixture. Adding powder to be lithiated to the first lithium-containing solution to achieve absorption of combined lithium, and obtaining lithium-rich powder and a mixed solution after solid-liquid separation, wherein the mixed solution can be used for the preparation of the lithiation-capable substrate solution after distillation. Adding a leaching agent to the lithium-rich powder for acid leaching to obtain a second lithium-containing solution; adding a lithium precipitating agent to the second lithium-containing solution to obtain lithium salts for recovery.

[0092] In order to make the details and operations of the above embodiments of the present application clearly understood by those skilled in the art, and to significantly demonstrate the improved performance of the metal lithium battery recycling method of the embodiments of the present application, the above technical solutions are illustrated by multiple embodiments below.

[0093] Example 1

[0094] Step 1: crushing metal lithium batteries under an inert atmosphere to obtain battery waste containing metal lithium, wherein the batch of batteries uses DME as the electrolyte;

[0095] Step 2: using DME as the first solvent and aromatic naphthalene as the lithiation substrate to prepare a lithiation substrate solution;

[0096] Step 3: mixing the battery waste obtained in step 1 with the lithiation-capable substrate solution in step 2, and stirring the mixture to allow metallic lithium to lithiate the aromatic hydrocarbon naphthalene, wherein the amount of the aromatic hydrocarbon naphthalene added is 1.3 times the molar amount of lithium in the battery waste;

[0097] Step 4: Filter and separate to obtain the first lithium-containing solution and the battery mixture;

[0098] Step 5: adding silicon powder to the first lithium-containing solution to adsorb lithium ions to form lithium-rich powder, wherein the molar amount of lithium that can be absorbed by the silicon powder is 1.2 times the molar amount of lithium in the battery waste;

[0099] Step 6: Filter and separate to obtain lithium-rich powder and mixed solution;

[0100] Step 7: The lithium-rich powder is placed in sulfuric acid with a hydrogen ion concentration of 4 mol / L to leach lithium, wherein the reaction temperature is 90°C;

[0101] Step 8: filtering and separating the delithiation powder and the second lithium-containing solution;

[0102] Step nine: add sodium carbonate (lithium precipitating agent) to the second lithium-containing solution obtained in step five, control the pH value to 10, the reaction temperature to 90° C., and filter to obtain lithium carbonate.

[0103] Example 2

[0104] Step 1: crushing metal lithium batteries under an inert atmosphere to obtain battery waste containing metal lithium, wherein this batch of batteries uses FEC and DMC as electrolyte;

[0105] Step 2: using DMC as the first solvent and aromatic hydrocarbon anthracene as the lithiation substrate to prepare a lithiation substrate solution;

[0106] Step 3: mixing the battery waste obtained in step 1 with the lithiation substrate solution obtained in step 2 and stirring the mixture to allow the metallic lithium to lithiate the aromatic hydrocarbon anthracene, wherein the amount of the aromatic hydrocarbon anthracene added is 1.4 times the molar amount of lithium in the battery waste;

[0107] Step 4: Filter and separate to obtain the first lithium-containing solution and the battery mixture;

[0108] Step 5: adding silicon powder to the first lithium-containing solution to adsorb lithium ions to form lithium-rich powder, wherein the molar amount of lithium that can be absorbed by the silicon powder is 1.3 times the molar amount of lithium in the battery waste;

[0109] Step 6: Filtration and separation to obtain lithium-rich powder and a mixed solution; distilling the mixed solution at 100°C to separate DMC, which is reused as the first solvent in step 3; distilling at 220°C to separate FEC; and the remaining anthracene is reused as a lithiation substrate in step 3;

[0110] Step 7: The lithium-rich powder is placed in hydrochloric acid with a hydrogen ion concentration of 4 mol / L to leach lithium, wherein the reaction temperature is 90°C;

[0111] Step 8: filtering and separating the delithiation powder and the second lithium-containing solution;

[0112] Step nine: add sodium carbonate (lithium precipitating agent) to the second lithium-containing solution obtained in step five, control the pH value to 10, the reaction temperature to 90° C., and filter to obtain lithium carbonate.

[0113] The lithium recovery rate and lithium salt purity test of Example 1-2 are shown in Table 1 below:

[0114]

[0115] It can be seen that the metal lithium battery recovery method provided in the embodiment of the present application can achieve a higher lithium recovery rate and lithium salt purity.

[0116] The above experimental results show that the embodiments of the present application effectively improve the recovery rate of the ternary positive electrode material and the purity of the recovered product.

Claims

1. A method for recycling metal lithium batteries, characterized in that: The method includes: Providing battery waste, wherein the battery waste contains metallic lithium; Mixing a lithiation-capable substrate with a first solvent to obtain a lithiation-capable substrate solution, wherein the lithiation-capable substrate is selected from at least one of naphthalene, anthracene, and biphenyl, and the first solvent is selected from DME and / or DMC; Mixing the lithiation substrate solution with the battery waste, and obtaining a first lithium-containing solution after solid-liquid separation, wherein the first lithium-containing solution contains an organic lithium compound; Adding a powder to be lithiated to the first lithium-containing solution, and obtaining a lithium-rich powder after solid-liquid separation, wherein the powder to be lithiated is selected from at least one of silicon powder, graphite powder, hard carbon powder, and silicon-carbon powder; acid leaching the lithium-rich powder to obtain a second lithium-containing solution; A lithium precipitating agent is added to the second lithium-containing solution to obtain a lithium salt.

2. The method according to claim 1, wherein The amount of the lithiation substrate added is 1.2 to 1.5 times the molar amount of lithium in the battery waste.

3. The method according to claim 1, wherein The first solvent is the same as the electrolyte contained in the battery waste.

4. The method according to claim 1, wherein The molar amount of lithium that can be absorbed by the powder to be lithiated is 1.2 to 1.5 times the molar amount of lithium in the battery waste.

5. The method according to claim 1, wherein The leaching agent used in the acid leaching includes: at least one of sulfuric acid and hydrochloric acid; and / or, the hydrogen ion concentration of the leaching agent used in the acid leaching is 1 to 4 mol / L; And / or, the leaching temperature of the acid leaching is 50-95°C.

6. The method according to claim 1, wherein After the step of acid leaching the lithium-rich powder, the method further comprises: Solid-liquid separation to obtain lithium-free powder; The delithiated powder is used as the powder to be lithiated.

7. The method according to claim 1, wherein The lithium precipitating agent includes at least one of sodium carbonate, sodium phosphate and sodium fluoride.

8. The method according to claim 1, wherein The step of adding a lithium precipitation agent to the second lithium-containing solution comprises: Control the pH to 9~11 and the reaction temperature to 50~95℃.

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