Recovery method of metal lithium battery

Abstract

The invention discloses a recovery method of a metal lithium battery, relates to the technical field of lithium battery recovery, and discloses the recovery method of the metal lithium battery, which comprises the following steps: providing a battery waste material containing metal lithium; the battery waste is mixed with a lithiated substrate, a first lithium-containing solution is obtained after solid-liquid separation, and the first lithium-containing solution contains an organic lithium compound; adding powder to be lithiated into the first lithium-containing solution, and performing solid-liquid separation to obtain lithium-rich powder; the lithium-rich powder is subjected to acid leaching, and a second lithium-containing solution is obtained; and adding a lithium precipitating agent into the second lithium-containing solution to obtain the lithium salt. The metal lithium battery recycling process is free of violent reaction, simple and convenient in process and high in safety.

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 gradually become a popular choice for the next generation of high energy density batteries due to their high energy density (theoretical capacity up to 3860mAh / g) and low electrode potential (-3.04 V vs. SHE). However, the high activity of metallic lithium also brings significant safety hazards and recycling challenges. During the battery cycle, lithium dendrites are easily formed on the metallic lithium negative electrode. These dendrites may pierce the diaphragm, causing the battery to short-circuit or even cause thermal runaway, thereby producing flammable gases such as hydrogen, increasing the risk of explosion. In addition, the side reactions of metallic lithium with the electrolyte will continuously consume lithium and electrolyte, resulting in battery capacity decay and shortened life.

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

[0004] The above contents are only used to assist in understanding the technical solution of the present application and do not constitute an admission that the above contents are prior art. Summary of the invention

[0005] The main purpose of the present 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: Providing battery waste, wherein the battery waste contains metallic lithium; The battery waste is mixed with a lithiation-capable substrate, and a first lithium-containing solution is obtained after solid-liquid separation, wherein the first lithium-containing solution contains an organic lithium compound; Adding the powder to be lithiated to the first lithium-containing solution, and obtaining lithium-rich powder after solid-liquid separation; 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.

[0007] In one embodiment, the lithiation-capable substrate includes: aromatic hydrocarbons.

[0008] In one embodiment, the amount of the lithiation substrate added is 1.2 to 1.5 times the molar amount of lithium in the battery waste.

[0009] In one embodiment, the step of mixing the battery waste with a lithiation-capable substrate comprises: 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; The lithiatable substrate solution is mixed with the battery waste.

[0010] In one embodiment, the powder to be lithiated includes at least one of silicon powder, graphite powder, hard carbon powder and silicon-carbon powder.

[0011] 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.

[0012] In one embodiment, 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.

[0013] In one embodiment, after the step of acid leaching the lithium-rich powder, the method further comprises: Solid-liquid separation to obtain lithium-free powder; The delithiation powder is used as the powder to be lithiated.

[0014] In one embodiment, the lithium precipitating agent includes at least one of sodium carbonate, sodium phosphate and sodium fluoride.

[0015] In one embodiment, the step of adding a lithium precipitating agent to the second lithium-containing solution comprises: Control the pH value to 9~11 and the reaction temperature to 50~95 ℃.

[0016] 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 substrate; using the lithiation 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 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. There is no violent reaction in the recovery process of the embodiment of the present application, the process is simple and safe, and high-purity lithium salts can be directly separated and recovered. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] 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.

[0018] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0019] Figure 1 A schematic diagram of a process flow diagram provided for the first embodiment of the method for recycling a lithium metal battery of the present application; Figure 2 This is a flow chart of a relatively complete embodiment of the metal lithium battery recycling method of the present application.

[0020] The purpose, features and advantages of this application will be further described in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0022] Hereinafter, the embodiment of the method for recycling a metal lithium battery of the present application is specifically disclosed in detail with appropriate reference to the accompanying drawings. However, there may be cases where unnecessary detailed descriptions are omitted. For example, there are cases where detailed descriptions of well-known matters and repeated descriptions of actually the same structure are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the drawings and the following description are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0023] The "range" disclosed in the present application is defined in the form of a lower limit and an upper limit, and 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 end values, and can be arbitrarily combined, that is, 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 ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, 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 the present 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, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it 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.

[0024] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0025] 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.

[0026] If there is no special explanation, all steps of the present application can be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means 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), which means 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.

[0027] If there is no special explanation, the "include" and "comprising" mentioned in this application are open-ended or closed-ended. For example, the "include" and "comprising" may mean that other components not listed may also be included or only the listed components may be included or only the listed components may be included.

[0028] If not specifically stated, in this application, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B": 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).

[0029] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and understandable, the technical solution of the present application is further described below in conjunction with the accompanying drawings and embodiments. However, the present application is not limited to the listed embodiments, and should also include any other known changes within the scope of the rights claimed in the present application.

[0030] The term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present application. The term "in one embodiment" that appears in different places in 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.

[0031] 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.

[0032] In conventional technology, the recycling technology for lithium metal batteries is relatively limited and complicated. For example, physical disassembly requires strict control of environmental conditions to avoid moisture contact; although 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 a large amount of chemical reagents and is costly; at the same time, metal lithium is very easy to react with air or moisture during the recycling process to generate hydrogen, which increases the operational risk.

[0033] The present application provides a solution, by mixing battery waste containing metallic lithium with a lithiation substrate; using the lithiation 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 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. There is no violent reaction in the recovery process of the embodiment of the present application, the process is simple and safe, and high-purity lithium salts can be directly separated and recovered.

[0034] Based on this, the present application embodiment provides a method for recycling a metal lithium battery, referring to Figure 1 , Figure 1 This is a schematic diagram of the process of the first embodiment of the recycling method of metal lithium batteries of the present application. In this embodiment, the recycling method of metal lithium batteries includes: Step S10, providing battery waste, wherein the battery waste contains metallic lithium; In a feasible embodiment, metallic lithium batteries can be crushed to obtain battery waste containing metallic lithium.

[0035] Lithium metal batteries usually refer to batteries with lithium metal as the negative electrode. This type of battery takes advantage of the fact that lithium metal can efficiently embed and de-embed ions during the charging and discharging process, thereby achieving energy storage and release. Lithium metal batteries have attracted much attention due to their high energy density and lightweight advantages.

[0036] Exemplarily, waste batteries are crushed under an inert atmosphere to obtain battery waste containing metallic lithium.

[0037] 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; In a feasible embodiment, the battery waste is mixed with a lithiation-capable substrate, the lithiation-capable substrate is used to absorb metallic lithium and convert it into a soluble organic lithium compound, and a first lithium-containing solution containing the organic lithium compound and a battery mixture are obtained through solid-liquid separation.

[0038] In one feasible embodiment, step S20, the step of mixing the battery waste with the lithiation-capable substrate comprises: 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; Step S22, mixing the lithiation-capable substrate solution with the battery waste.

[0039] In a feasible embodiment, the lithiation substrate can be first mixed with a first solvent to obtain a lithiation substrate solution; and then the lithiation substrate solution is mixed with the battery waste so that the metallic lithium can fully react with the lithiation substrate. The first solvent can be the same as the electrolyte contained in the battery waste to avoid the introduction of new impurities.

[0040] Optionally, the first solvent is the same as the metal lithium battery electrolyte and can be separated by distillation.

[0041] Optionally, the first solvent includes: an ether solvent and / or an ester solvent.

[0042] Exemplarily, the first solvent includes at least one of dimethoxyethane (DME), ethyl methyl carbonate (EMC) and 1,3-dioxolane (DOL).

[0043] In one feasible embodiment, the lithiation-capable substrate includes: aromatic hydrocarbons.

[0044] Aromatic hydrocarbons can absorb metallic lithium and convert it into soluble organolithium compounds. This reaction can provide an effective way to treat highly active metallic lithium and convert it into a more stable and easy-to-handle form. For example, benzene reacts with metallic lithium to form phenyllithium (pHLi). This type of organolithium compound has good solubility in solution and is easy to use in subsequent chemical reactions or process steps. Secondly, there are high risks in directly handling metallic lithium, including the possibility of fire and explosion; converting metallic lithium into stable organolithium compounds not only improves the safety of operation, but also reduces potential environmental pollution problems.

[0045] Exemplarily, the lithiation-capable substrate includes at least one of benzene, naphthalene, anthracene and biphenyl.

[0046] Benzene is one of the simplest and most commonly used aromatic hydrocarbons, which is easy to obtain and has low cost. Phenyllithium is a very useful organic synthesis reagent, which is often used to prepare other organolithium compounds or as a strong base. The process of benzene reacting with metallic lithium to form phenyllithium is relatively mild and easy to control, which is suitable for application in laboratory scale and industrial production.

[0047] Compared to benzene, naphthalene has higher reactivity and can be more easily subjected to lithiation reactions. The resulting naphthyl lithium is also an important intermediate in organic synthesis. Due to its high basicity and nucleophilicity, naphthyl lithium performs well in certain types of organic reactions.

[0048] Anthracene is a polycyclic aromatic hydrocarbon with a higher conjugation system than benzene and naphthalene, which allows it to generate anthracene lithium when reacting with metallic lithium, a reagent that is particularly suitable for certain selective organic synthesis reactions. Anthracene lithium exhibits special reaction characteristics due to its unique electronic structure, such as selective lithiation of specific sites in some cases.

[0049] Although biphenyl is not as commonly used as the above aromatic hydrocarbons, it can also react with metallic lithium to form biphenyl lithium under appropriate conditions. Due to its rigidity and large steric hindrance, biphenyl and its derivatives show unique advantages under some special conditions.

[0050] In one feasible embodiment, the amount of the lithiation substrate added is 1.2 to 1.5 times the molar amount of lithium in the battery waste. For example, the amount of the lithiation substrate added is 1.2 times, 1.25 times, 1.3 times, 1.35 times, 1.4 times, 1.45 times, 1.5 times, etc., the molar amount of lithium in the battery waste.

[0051] 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 hydrocarbons added is too much, it may first lead to a decrease in cost-effectiveness, because the excess aromatic hydrocarbons not only waste raw materials, but also increase 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 will further affect the reaction efficiency and product purity. On the contrary, when the amount of aromatic hydrocarbons added is insufficient, the main problem is that metallic lithium may not be completely converted into organic lithium compounds. The unreacted metallic lithium residue not only reduces the yield of the target product, but also brings safety hazards, because metallic lithium is very active and easily reacts violently with moisture in the air, and even causes fire or explosion. In addition, incomplete conversion of metallic lithium means that there may be a risk of local overheating in the reaction system, especially in large-scale production processes, this phenomenon is particularly dangerous. The amount of lithium absorbed by the lithiation substrate (eg, aromatic hydrocarbon) is one molecule absorbing one lithium ion. 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.

[0052] Step S30, adding the powder to be lithiated to the first lithium-containing solution, and obtaining lithium-rich powder after solid-liquid separation; In a feasible embodiment, powder to be lithiated is further added to the first lithium-containing solution, and the powder to be lithiated is used to adsorb lithium ions to form lithium-rich powder, and the lithium-rich powder and a mixed solution are obtained by solid-liquid separation.

[0053] Exemplarily, the powder to be lithiated is added to the first lithium-containing solution, and the solution is stirred at a speed of 20-100 r / min to adsorb lithium ions to form lithium-rich powder.

[0054] 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.

[0055] 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 times, 1.25 times, 1.3 times, 1.35 times, 1.4 times, 1.45 times, 1.5 times, etc., the molar amount of lithium that can be absorbed by the powder to be lithiated is the molar amount of lithium in the battery waste.

[0056] In the process of using the lithium powder to be lithiated to adsorb lithium ions in the solution to form a lithium-rich powder, the amount of the powder to be lithiated has a crucial impact on the final effect. When the amount of powder to be lithiated is too much, the cost will increase and resources may be wasted. Secondly, too much adsorbent may cause the viscosity of the reaction system to be too high or the solid-liquid separation to be difficult. Especially when using materials such as silicon, due to its large specific surface area and potential agglomeration tendency, excessive addition will lead to uneven dispersion, thereby affecting the effective adsorption efficiency of lithium ions. In addition, in subsequent processing steps, processes such as filtration and washing will become more complicated, increasing the difficulty of operation and energy consumption. On the contrary, when the amount of powder to be lithiated is insufficient, the adsorption capacity may not reach the expected target, resulting in a decrease in the recovery rate of lithium. Because the density of different powders to be lithiated and the amount of metal lithium that can be absorbed are different, therefore, the embodiment of the present application sets the molar amount of lithium that can be absorbed by the powder to be lithiated to be 1.2~1.5 times the molar amount of lithium in the battery waste to control the amount of powder to be lithiated.

[0057] 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.

[0058] Step S40, acid leaching the lithium-rich powder to obtain a second lithium-containing solution; 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, separate the solid and the liquid, and obtain a second lithium-containing solution and a lithium-depleted powder.

[0059] Optionally, the hydrogen ion concentration of the leaching agent used for acid leaching is 1 to 4 mol / L; for example, the hydrogen ion concentration of the leaching agent used for 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.

[0060] Optionally, the leaching agent used for acid leaching includes at least one of sulfuric acid and hydrochloric acid.

[0061] Optionally, the leaching temperature of the acid leaching can be: 50°C, 60°C, 70°C, 80°C, 90°C, 95°C, etc.

[0062] In one feasible implementation, after the step of acid leaching the lithium-rich powder in step S40, the method further includes: Step S41, solid-liquid separation to obtain lithium-free powder; Step S42, using the delithiated powder as the powder to be lithiated.

[0063] 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.

[0064] Step S50, adding a lithium precipitating agent to the second lithium-containing solution to obtain a lithium salt.

[0065] In a feasible embodiment, a lithium precipitator is added to the second lithium-containing solution, the pH value 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, safe and efficient recovery of lithium elements is achieved.

[0066] Optionally, the lithium precipitating agent includes at least one of sodium carbonate, sodium phosphate and sodium fluoride.

[0067] Alternatively, the pH value may be 9, 10, 11, etc.

[0068] Optionally, the reaction temperature can be: 50°C, 60°C, 70°C, 80°C, 90°C, 95°C, etc.

[0069] In this embodiment, the battery waste containing metallic lithium is mixed with a lithiation substrate; the lithiation 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. There is no violent reaction in the recovery process of the embodiment of the present application, the process is simple and safe, and high-purity lithium salts can be directly separated and recovered.

[0070] To assist in understanding the above technical solution, a relatively complete embodiment of the recycling method of metal lithium batteries is described below. Figure 2 , provide waste lithium metal batteries, crush the batteries under an inert atmosphere to obtain battery waste containing lithium metal. Provide a lithiation-capable substrate solution and mix it with the battery waste, use the lithiation-capable substrate to absorb metallic lithium, convert it into a soluble organic lithium compound, separate the solid and liquid, and obtain a first lithium-containing solution and a battery mixture. Add the powder to be lithiated to the first lithium-containing solution to achieve absorption of combined lithium, and obtain 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. Add a leaching agent to the lithium-rich powder for acid leaching to obtain a second lithium-containing solution; add a lithium precipitating agent to the second lithium-containing solution to obtain lithium salts for recovery.

[0071] In order to enable the details and operations of the above-mentioned embodiments of the present application to be 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-mentioned technical scheme is illustrated by means of multiple embodiments below.

[0072] Example 1 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; Step 2: using DME as the first solvent and aromatic naphthalene as the lithiation substrate to prepare a lithiation substrate solution; Step 3: mixing the battery waste obtained in step 1 with the lithiation substrate solution in step 2, and stirring the mixture to allow metallic lithium to lithiation 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; Step 4: filtering and separating to obtain a first lithium-containing solution and a battery mixture; Step 5: adding silicon powder to the first lithium-containing solution to absorb 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; Step 6: Filter and separate to obtain lithium-rich powder and mixed solution; Step 7: Put the lithium-rich powder into sulfuric acid with a hydrogen ion concentration of 4 mol / L to leach lithium elements, wherein the reaction temperature is 90 °C; Step 8: filtering and separating the de-lithiumized powder and the second lithium-containing solution; 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.

[0073] Example 2 Step 1: crushing metal lithium batteries under an inert atmosphere to obtain battery waste containing metal lithium, wherein the batch of batteries uses EC, DMC and EMC as electrolytes; Step 2: using EC as the first solvent and aromatic biphenyl as the lithiation substrate to prepare a lithiation substrate solution; Step 3: mixing the battery waste obtained in step 1 with the lithiation substrate solution in step 2, and stirring the mixture to allow metallic lithium to lithiation the aromatic biphenyl, wherein the amount of the aromatic biphenyl added is 1.2 times the molar amount of lithium in the battery waste; Step 4: filtering and separating to obtain a first lithium-containing solution and a battery mixture; Step 5: adding hard carbon 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 hard carbon powder is 1.2 times the molar amount of lithium in the battery waste; Step 6: Filter and separate to obtain lithium-rich powder and a mixed solution; distill the mixed solution at 150 °C to separate DMC and EMC, and the remaining EC and biphenyl solution are reused in step 3; Step 7: Put the lithium-rich powder into hydrochloric acid with a hydrogen ion concentration of 4 mol / L to leach lithium elements, wherein the reaction temperature is 90 °C; Step 8: filtering and separating the de-lithiumized powder and the second lithium-containing solution; 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.

[0074] Example 3 Step 1: crushing metal lithium batteries under an inert atmosphere to obtain battery waste containing metal lithium, wherein the batch of batteries uses FEC and DMC as electrolyte; Step 2: using DMC as the first solvent and aromatic hydrocarbon anthracene as the lithiation substrate to prepare a lithiation substrate solution; Step 3: mixing the battery waste obtained in step 1 with the lithiation substrate solution in step 2, and stirring to allow metallic lithium to lithiation the aromatic hydrocarbon anthracene, wherein the amount of aromatic hydrocarbon anthracene added is 1.4 times the molar amount of lithium in the battery waste; Step 4: filtering and separating to obtain a first lithium-containing solution and a battery mixture; Step 5: adding silicon powder to the first lithium-containing solution to absorb 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; Step 6: Filter and separate to obtain lithium-rich powder and a mixed solution; distill the mixed solution at 100 °C to separate DMC, which is reused as the first solvent in step 3; distill and separate FEC at 220 °C; and the remaining anthracene is reused as a lithiation substrate in step 3; Step 7: Put the lithium-rich powder into hydrochloric acid with a hydrogen ion concentration of 4 mol / L to leach lithium elements, wherein the reaction temperature is 90 °C; Step 8: filtering and separating the de-lithiumized powder and the second lithium-containing solution; 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.

[0075] The lithium recovery rate and lithium salt purity of Examples 1-3 were tested, and the results are shown in Table 1 below: Table 1. Lithium recovery rate and lithium carbonate purity of various examples of metal lithium batteries

[0076] 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.

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; The battery waste is mixed with a lithiation-capable substrate, and a first lithium-containing solution is obtained after solid-liquid separation, wherein the first lithium-containing solution contains an organic lithium compound; Adding the powder to be lithiated to the first lithium-containing solution, and obtaining lithium-rich powder after solid-liquid separation; 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, characterized in that The lithiation-capable substrate includes aromatic hydrocarbons.

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

4. The method according to claim 1, characterized in that The step of mixing the battery waste with a lithiation-capable substrate comprises: 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; The lithiatable substrate solution is mixed with the battery waste.

5. The method according to claim 1, characterized in that The powder material to be lithiated includes at least one of silicon powder, graphite powder, hard carbon powder and silicon-carbon powder.

6. The method according to claim 1 or 5, characterized in that 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.

7. The method according to claim 1, characterized in that 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.

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

9. The method according to claim 1, characterized in that The lithium precipitating agent comprises at least one of sodium carbonate, sodium phosphate and sodium fluoride.

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

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