Methods and systems for recovering electrode metals from used lithium-ion batteries

Abstract

A method for obtaining electrode metal from an electrode of a lithium-ion (Li-ion) battery includes separating the electrode portion from a used Li-ion battery. The leaching solvent is brought into contact with the separated electrode portion to form an electrode dispersion. The electrode dispersion is heated to a temperature within the range of about 50°C to about 90°C by applying microwave radiation. The temperature of the electrode dispersion is maintained within the range of about 50°C to about 90°C for a period within the range of about 10 seconds to about 5 minutes by further applying microwave radiation to the heated electrode dispersion. The electrode dispersion is then filtered to obtain the electrode metal.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims the benefit of priority to U.S. Provisional Application No. 63 / 342,422, filed May 16, 2022, and U.S. Provisional Application No. 63 / 392,290, filed Jul. 26, 2022, each of which is hereby incorporated by reference in its entirety.

[0002] The present disclosure generally relates to the field of recycling of used lithium - ion batteries, and more specifically, to systems and methods for recovering electrode metals from used lithium - ion batteries.

Background Art

[0003] As the use of electric devices, including automobiles, increases, the use of batteries continues to grow. As a result, over time, the number of used batteries will also increase. However, the amount of metals and other natural resources used as battery raw materials is limited. Therefore, in order to continue producing more batteries, it is necessary to recover raw materials by recycling used batteries.

[0004] A typical lithium - ion battery includes a plastic that forms part of the battery's protective cover and separator, an anode containing anode metals such as copper and black mass, a cathode containing cathode metals such as aluminum and black mass, and black mass that forms part of the separator. Black mass generally contains, in addition to lithium, graphite, and oxides of several valuable metals such as iron, cobalt, manganese, nickel, copper, and aluminum, which typically form only about 1% of the battery weight.

[0005] Most of the current technologies for recycling used lithium batteries utilize pyrometallurgical processes such as smelting that require high temperatures in the range of, for example, about 500 °C to about 1400 °C. As a result, the cost of metal recovery is substantially higher than the price of the recovered metal. Moreover, the amount of each metal recovered is also typically low compared to, for example, hydrometallurgical processes.

[0006] Hydrometallurgical processes can provide higher yields and potentially higher purity of the recovered metal, but these processes generally require heating the leaching solvent for an extended period at relatively high temperatures, for example, in the range of about 100 °C to about 400 °C. Therefore, the energy requirements of such processes remain high. Moreover, the handling of hot leaching solvents poses certain risks that further increase the cost of such processes.

[0007] As a result, current technologies for recycling used batteries are less cost-effective compared to technologies for newly obtaining these materials. Therefore, there is a need for a cost-effective, low-energy, sustainable, and low-carbon footprint technology for recovering materials from used batteries. SUMMARY OF THE INVENTION

[0008] The embodiments disclosed herein are derived from the recognition that high temperature and / or high temperature chemical technologies are not required to recover metals from the electrodes of used lithium ion batteries. This application discloses a system and method for obtaining electrode metals from used lithium ion batteries using a leaching solvent in the presence of an oxidizing agent. Since the leaching solvent used in the embodiments of the present disclosure is an aqueous solution, microwave radiation can be utilized to heat the leaching solvent to a suitable temperature and reduce the time and energy required to maintain the temperature at which the metal dissolves in the leaching solvent.

[0009] The leaching solvent of the embodiments of the present disclosure is selected to be able to dissolve all the various metals used in lithium-ion batteries. Therefore, when the electrodes of a lithium-ion battery come into contact with the leaching solvent at a suitable temperature, all the various metals from the battery are dissolved in the leaching solvent. Advantageously, the embodiments disclosed herein enable the recovery of high-purity electrode metals from used lithium-ion batteries without using a thermochemical process, thereby substantially reducing the time, cost, and carbon footprint for recovering electrode metals from lithium-ion batteries.

[0010] Accordingly, in at least one embodiment, a method of obtaining electrode metal from the electrodes of a lithium-ion (Li-ion) battery includes separating the electrode portion from a used Li-ion battery. A leaching solvent is contacted with the separated electrode portion to form an electrode dispersion. The electrode dispersion is heated to a temperature within the range of 50°C to 90°C by applying microwave irradiation. The temperature of the electrode dispersion is maintained within the range of 50°C to 90°C for a period within the range of 10 seconds to 10 minutes (e.g., 10 seconds, 30 seconds, 1 minute, 2 minutes, 3 minutes, 4 minutes, 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, or any time between any two of these times) by further applying microwave radiation to the heated electrode dispersion. The electrode dispersion is then filtered to obtain the electrode metal.

[0011] According to at least one embodiment, a system for recovering electrode metal from a used lithium-ion battery includes a reaction chamber, a microwave radiation source coupled to the reaction chamber, a microwave controller coupled to the microwave radiation source, a temperature sensor coupled to the reaction chamber and the microwave controller, and a filtration device coupled to the reaction chamber. The reaction chamber is configured to contain a leaching solvent and black mass from the used lithium battery. The microwave radiation source is configured to heat the leaching solvent in the reaction chamber by providing a predetermined amount of microwave radiation power to the leaching solvent. The microwave controller receives a temperature measurement from the temperature sensor and controls the microwave radiation source to heat the leaching solvent in the reaction chamber to be within the range of 50°C to 90°C over a period within the range of 10 seconds to 5 minutes, and to maintain the temperature of the leaching solvent in the reaction chamber within the range of 50°C to 90°C. The filtration device is configured to filter the leaching solvent from the reaction chamber to separate the leaching solvent from the undissolved black mass.

[0012] Additional features and advantages of the subject technology are described in the following description, some of which will be apparent from the description, or can be learned by practice of the subject technology. The advantages of the subject technology will be realized and achieved by the structures particularly pointed out in the written description and embodiments of this specification and the appended drawings.

[0013] It is to be understood that both the foregoing general description and the following detailed description of the invention are examples and explanations and are intended to provide further explanation of the subject technology.

[0014] Various features of the exemplary embodiments of the present disclosure are described below with reference to the drawings. The embodiments shown are intended to illustrate the present disclosure but not to limit the present disclosure. The drawings include the following figures:

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

DETAILED DESCRIPTION OF THE INVENTION

[0016] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the subject technology. It should be understood that the subject technology may be practiced without some of these specific details. In other instances, well-known structures and techniques are not shown in detail so as not to obscure the subject technology.

[0017] Furthermore, while this description sets forth specific details of various embodiments, it should be understood that the description is illustrative only and should not be construed as limiting. Additionally, while particular embodiments of the present disclosure may be disclosed or shown in the context of recycling a particular type of lithium battery, it is contemplated that such embodiments can be used with all types of lithium-ion batteries. Further, various applications of such embodiments and their modifications that may be envisioned by those skilled in the art are also encompassed by the general concepts described herein.

[0018] The cathode for a typical lithium-ion battery includes aluminum and black mass, which mainly contains graphite powder and salts of one or more valuable metals such as lithium, cobalt, manganese, nickel, iron, etc. Similarly, a typical anode of a lithium-ion battery includes copper and black mass.

[0019] Figure 1 shows a schematic diagram of an apparatus 100 for recycling used lithium-ion batteries according to at least some embodiments of the present disclosure. In some embodiments, the apparatus 100 includes a grinder 102, a washing chamber 104, one or more chemical storage tanks 106, a controller 108, one or more reaction chambers such as a separation chamber 110, a precipitation chamber 112, one or more wash water tanks 114, one or more recycled water tanks 116, and one or more pumps 120.

[0020] In some embodiments, the grinder 102 is designed to break the cells of a used lithium-ion battery (also referred to herein as a "used battery" for convenience of reference) into fragments having dimensions in the range of about 1 mm to about 5 cm. In some embodiments, the grinder 102 may include a chamber that is sealed and can be evacuated to reduce the amount of oxygen in the chamber, thereby preventing oxidation of the fragments of the used battery. In some embodiments, the chamber can be repressurized using an inert gas such as nitrogen or argon, for example.

[0021] In some embodiments, the washing chamber 104 is designed to wash the fragments of the used battery obtained from the grinder 102. Washing the fragments can include processes such as washing the fragments with water (e.g., distilled water), subjecting the fragments to ultrasonic treatment in water or after drying the washed fragments, and drying the washed and / or ultrasonically treated fragments.

[0022] In some embodiments, the washing can be performed at room temperature or at an elevated temperature. In some embodiments, the washing can be performed in air at atmospheric pressure. Alternatively, or additionally, the washing can be performed in a vacuum and / or in an inert atmosphere, for example, in the presence of nitrogen, argon, etc.

[0023] In some embodiments, cleaning the fragments may include dispersing the fragments of the used battery in a fluid and filtering the fragments using one or more filtration processes such as using one or more meshes each having a different mesh size. In some embodiments, the mesh size can range from about 50 μm to about 5 mm. For example, the filtration process can include filtering the dispersion through a mesh having a mesh size of about 5 mm, subsequently filtering through a mesh having a mesh size of about 1 mm, subsequently filtering through a mesh having a mesh size of about 500 μm, and subsequently sequentially filtering through a mesh having a mesh size of about 50 μm. In some embodiments, one or more of these steps may be omitted. Alternatively, or additionally, one or more filtration steps may be added to the process.

[0024] In some embodiments, one or more storage tanks 106 may store chemicals such as leaching chemicals, acids, neutralizing solutions (e.g., alkaline solutions, acid solutions, salt solutions, etc.), water, and / or other unique solutions containing one or more chemicals useful in the recycling process.

[0025] In some embodiments, each of the one or more storage tanks 106 may be connected to one or more reaction chambers 110, 112. Further, the connection between the storage tank and the reaction chamber may include a control valve that can be controlled by the controller 108. The controller 108 is configured to control the amount of chemical transferred from the storage tank 106 to the reaction chambers 110, 112 via the control valve (or other mechanism). For example, the controller 108 may control parameters such as the volume and / or flow rate of the chemical transferred from the storage tank to the corresponding reaction chamber.

[0026] In some embodiments, the controller 108 may control the volume, mass, and / or flow rate of a chemical substance transferred from a storage tank to a given reaction chamber by utilizing control parameters such as, for example, pH, temperature, volume, turbidity, density, and / or other parameters associated with the chemical substances within a given reaction chamber.

[0027] In some embodiments, the controller 108 may control the temperature of the materials within a reaction chamber, for example, by controlling the amount of heat delivered to the reaction chamber or the materials within the reaction chamber. For example, in some embodiments, the controller 108 may control the power output to a microwave generator coupled to the reaction chamber to control the microwave energy delivered to the materials within the reaction chamber. The controller 108 may control the power output based on parameters such as, for example, the temperature of the materials within the reaction chamber.

[0028] In some embodiments, one or more reaction chambers may be connected to the wash water tank 114. The connection between the reaction chamber and the wash water tank may be controlled by a control valve in some embodiments. Similar to the connection between the reaction chamber and the storage tank, the controller 108 may control the amount of water transferred from the wash water tank 114 to the reaction chamber based on parameters such as pH, temperature, volume, turbidity, density, and / or other parameters associated with the chemical substances within a given reaction chamber via the control valve.

[0029] In some embodiments, one or more reaction chambers are further connected to a recycled water tank 116. When the reaction in the reaction chamber is completed, any solid materials generated, for example, precipitated and / or separated in the reaction chamber, are removed. The solid material can be removed, for example, by filtration. In some embodiments, the remainder of the chemical substances is neutralized using a neutralizing solution introduced into the reaction chamber from a corresponding storage tank via control of a control valve by, for example, a controller. In some embodiments, any precipitate resulting from the neutralization reaction is removed, for example, by filtration, and the remaining water is transferred to the recycled water storage tank 116.

[0030] In some embodiments, the transfer of materials to and / or from one or more of the storage tank 106, reaction chambers 110, 112, wash water tank 114, and / or recycled water tank 116 can be facilitated by one or more pumps 120. In some embodiments, one or more pumps 120 are coupled to a controller 108 that can control the one or more pumps 120 to control the flow rate and / or volume of the material being transferred.

[0031] In one aspect of the present disclosure, a suitable device, such as device 100 for example, can be utilized to recycle used batteries. In particular, in some embodiments, a device such as device 100 can be utilized to recover electrode metals, such as aluminum and / or copper, from used batteries.

[0032] Figure 2 illustrates a flowchart of a method 200 for recovering electrode metal from a used lithium-ion battery according to at least some embodiments of the present disclosure. The method 200 may include, at 202, separating the electrodes from the shredded lithium-ion battery. The separated electrode portion is contacted, at 204, with a leaching solvent to form an electrode dispersion. The electrode dispersion is heated, at 206, to a temperature within the range of about 50°C to about 90°C by applying microwave radiation to the electrode dispersion. At 208, the temperature of the heated electrode dispersion is maintained within the range of about 50°C to about 90°C over a period within the range of about 10 seconds to about 5 minutes via a controlled application of microwave radiation. At 210, the electrode dispersion is filtered to obtain the electrode metal.

[0033] In some embodiments, at 202, separating the electrode portion from the shredded lithium-ion battery may include steps such as separating the shredded portion through a series of sieves for separating materials of different sizes. For example, in some embodiments, the separation may include separating coarse fragments having a size within the range of about 0.5 mm to about 5 mm by utilizing a suitable sieve, and subsequently further separating finer fragments having a size within the range of about 50 μm to about 0.5 mm by utilizing a second suitable sieve.

[0034] Isolated fragments, e.g., coarse fragments, can be introduced in 204 into a reaction chamber where the coarse fragments are contacted with a leaching solvent. In some embodiments, the leaching solvent can include an acid such as, for example, sulfuric acid, hydrochloric acid, oxalic acid, etc. In some embodiments, the leaching solvent can include two or more acids. In some embodiments, the leaching solvent can further include an oxidizing agent such as, for example, hydrogen peroxide or nitric acid. In some embodiments, the concentration of the leaching solvent acid can be in the range of about 0.5N to about 10N. In some embodiments, the leaching solvent can have a pH of about 0. In some embodiments, the pH of the leaching solvent can be in the range of about 0 to about 7.0. In some embodiments, the leaching solvent is introduced from a storage tank into the reaction chamber. The introduction amount and rate of the leaching solvent can be controlled via a controller.

[0035] Table 1 provides the concentrations of various materials used in the leaching solvent according to one example.

[0036] Table 1: Specifications of the leaching solvent according to the example.

[0037]

Table 1

[0038] When the leaching solvent is introduced into the reaction chamber, the leaching solvent and the coarse fragments are stirred, for example, using a stirrer (which may or may not be controlled by a controller), to form an electrode dispersion.

[0039] Next, in 206, microwave radiation is applied to the electrode dispersion to heat the electrode dispersion to a temperature within the range of about 50°C to about 90°C. Therefore, in 206, the electrode dispersion can be heated to, for example, about 50°C, about 55°C, about 60°C, about 65°C, about 70°C, about 75°C, about 80°C, about 85°C, about 90°C, or any temperature between any two of these values.

[0040] In some embodiments, the application of microwave radiation is controlled by a controller that uses the temperature within the reaction chamber (e.g., the temperature determined using a temperature sensor coupled to the controller) as a feedback parameter. In some embodiments, the controller can be a proportional-integral-derivative (PID) controller, although other types of controllers are contemplated within the scope of the present disclosure.

[0041] In addition, in some embodiments, the electrode dispersion within the reaction chamber is stirred while being heated. Stirring of the electrode dispersion can help to more evenly distribute the heat generated by the application of microwave radiation throughout the electrode dispersion. Additionally, or alternatively, the electrode dispersion can be sonicated, for example, by applying ultrasonic waves during the heating process.

[0042] Once the temperature of the electrode dispersion reaches the desired value, at 208, the application of microwave radiation is continued for a period within the range of about 10 seconds to about 5 minutes to maintain the temperature at the desired value. For example, the temperature of the electrode dispersion can be maintained at the desired value for about 10 seconds, about 15 seconds, about 20 seconds, about 25 seconds, about 30 seconds, about 35 seconds, about 40 seconds, about 45 seconds, about 50 seconds, about 55 seconds, about 60 seconds, about 70 seconds, about 80 seconds, about 90 seconds, about 100 seconds, about 120 seconds, about 140 seconds, about 160 seconds, about 180 seconds, about 200 seconds, about 220 seconds, about 240 seconds, about 260 seconds, about 280 seconds, about 300 seconds, or any amount of time between any two of these values.

[0043] In some embodiments, the continuous application of microwave radiation at 208 is controlled using a controller, such as the same controller used at 206, for example. It should be understood that the continuous application of microwave radiation does not mean a constant application of microwave radiation. Therefore, in some embodiments, at 208, the microwave radiation can be applied in pulses. Each pulse can have a pulse width in the range of about 0.5 seconds to 5 seconds or more. The microwave pulses may or may not have the same peak power. Therefore, in some embodiments, the continuous application of microwave radiation can include the application of pulsed waves of microwave radiation and controlling parameters such as, for example, the pulse width, the peak power of the pulse, the pulse rate, and the total amount of time the microwave radiation is applied to the electrode dispersion.

[0044] In addition, at 208, the electrode dispersion can be agitated and / or sonicated using ultrasound to more uniformly disperse the heat generated from the application of microwave radiation through the electrode dispersion.

[0045] After maintaining the temperature of the electrode dispersion for a predetermined period, the electrode dispersion is filtered at 210. In some embodiments, the electrode dispersion can be cooled to room temperature before being filtered at 210. In some embodiments, filtering the electrode dispersion can include passing the electrode dispersion through one or more filters, meshes, or sieves. In some embodiments, the filter, mesh, or sieve can be designed or selected to enable separation of solid materials having different sizes. For example, a first mesh, filter, or sieve can separate solid materials having a size greater than about 5 mm, a second mesh, filter, or sieve can separate solid materials having a size in the range of about 1 mm to about 5 mm, a third mesh, filter, or sieve can separate solid materials having a size in the range of about 0.5 mm to about 1 mm, a fourth mesh, filter, or sieve can separate solid materials having a size in the range of about 100 μm to about 500 μm, a fifth mesh, filter, or sieve can separate solid materials having a size in the range of about 10 μm to about 100 μm, a sixth mesh, filter, or sieve can separate solid materials having a size in the range of about 1 μm to about 10 μm, and so on.

[0046] In embodiments where the used battery is pulverized in such a way that the fragments of the electrode portion have a size in the range of about 0.5 mm to about 5 mm, the filtration at 210 can be effective in separating the washed fragments of the electrode metal from the remaining portion of the solid material containing the black mass. It will be understood that the salts of the valuable metals from the black mass dissolve in the leaching solvent and the filtration process removes the insoluble portion of the black mass. Therefore, the metal pieces obtained after the filtration process can be pure metals with graphite powder.

Example

[0047] The contents of various materials found in different types of lithium-ion batteries were analyzed. Tables 2 to 7 provide the weight percentages of various materials present in different types of lithium batteries in different parts of the battery.

[0048] Table 2: Lithium Cobalt Oxide (LCO) Battery

[0049]

Table 2

[0050] Table 3: Lithium Nickel Cobalt Aluminum (LNCA) Battery

[0051]

Table 3

[0052] Table 4: Ratio of One-Third Each of Nickel, Manganese, and Cobalt in Active Cathode (NMC111) Battery

[0053]

Table 4

[0054] Table 5: Ratio of 60 / 20 / 20% of Nickel, Manganese, and Cobalt in Active Cathode (NMC622) Battery

[0055]

Table 5

[0056] Table 6: Ratio of 80 / 10 / 10% of Nickel, Manganese, and Cobalt in Active Cathode (NMC811) Battery

[0057]

Table 6

[0058] Table 7: Lithium Iron Phosphate (LFP) Battery

[0059] [Table 7]

[0060] 100 kg of LCO, LNCA, NMC622, and LFP (25 wt% contribution) batteries were recycled using the methods disclosed herein to recover the electrode metals.

[0061] Table 8 provides the amount of electrode metals recovered after the process.

[0062] Table 8: Amount of metal (salt) recovered after precipitation.

[0063] [Table 8]

[0064] Further Considerations In some embodiments, any of the clauses herein may depend on any one of the independent clauses or any one of the dependent clauses. In one aspect, any of the clauses (e.g., dependent or independent clauses) may be combined with any one or more other clauses (e.g., dependent or independent clauses). In one aspect, the claims may include some or all of the words (e.g., steps, actions, means, or components) listed within a clause, sentence, phrase, or paragraph. In one aspect, the claims may include some or all of the words listed within one or more clauses, sentences, phrases, or paragraphs. In one aspect, some of the words in each clause, sentence, phrase, or paragraph may be deleted. In one aspect, additional words or elements may be added within a clause, sentence, phrase, or paragraph. In one aspect, the technology of the subject matter may be implemented without using some of the components, elements, functions, or operations described herein. In one aspect, the technology of the subject matter may be implemented using additional components, elements, functions, or operations.

[0065] The technology of the subject matter is illustrated, for example, according to various aspects described below. Various examples of aspects of the technology of the subject matter are described, for the sake of convenience, as numbered clauses (1, 2, 3, etc.). These are provided as examples and do not limit the technology of the subject matter. Note that any of the dependent clauses can be combined in any combination and can be placed in each independent clause, for example, clause 1 or clause 5. Other clauses can also be presented in a similar manner.

[0066] Clause 1. A method for obtaining a metal from an electrode of a lithium-ion (Li-ion) battery, comprising separating an electrode portion from a pulverized Li-ion battery, contacting a leaching solvent with the separated electrode portion to form an electrode dispersion, heating the electrode dispersion to a temperature within the range of 50°C to 90°C by applying microwave radiation, maintaining the temperature of the electrode dispersion within the range of 50°C to 90°C for a period within the range of 10 seconds to 5 minutes by further applying microwave radiation to the heated electrode dispersion, and filtering the electrode dispersion to obtain the metal.

[0067] Clause 2. The method according to clause 1, wherein the metal comprises one of aluminum, copper, and iron.

[0068] Clause 3. The method according to clause 1, wherein the leaching solvent comprises sulfuric acid.

[0069] Clause 4. The method according to clause 1, wherein the leaching solvent has a pH within the range of 0 to 7.0.

[0070] Clause 5. The method according to clause 1, wherein heating the electrode dispersion further comprises stirring the electrode dispersion while applying microwave radiation.

[0071] Clause 6. The method according to clause 1, wherein maintaining the temperature of the electrode dispersion comprises controlling the application of microwave radiation using a controller.

[0072] Clause 7. The method according to Clause 1, wherein heating the electrode dispersion includes heating the electrode dispersion to a temperature within the range of 60°C to 80°C.

[0073] Clause 8. The method according to Clause 1, wherein maintaining the temperature includes maintaining the temperature of the electrode dispersion within the range of 60°C to 80°C for a period within the range of 30 seconds to 5 minutes.

[0074] Clause 9. The method according to Clause 1, wherein the electrode portion includes an electrode metal and a black mass including graphite and metal oxide.

[0075] Clause 10. The method according to Clause 9, wherein filtering the electrode dispersion includes filtering the electrode dispersion through a sieve to obtain graphite powder.

[0076] Clause 11. The method according to Clause 1, wherein heating the electrode dispersion further includes continuously stirring the electrode dispersion while applying microwave radiation.

[0077] Clause 12. The method according to Clause 1, wherein maintaining the temperature of the electrode dispersion further includes continuously stirring the electrode dispersion while applying microwave radiation.

[0078] Clause 13. A system for recycling used lithium-ion batteries, the system comprising: a crusher configured to break cells of the used lithium-ion battery into fragments; a washing chamber configured to wash the fragments; one or more storage tanks configured to store chemicals; one or more reaction chambers coupled to the one or more storage tanks via one or more pumps and valves, wherein at least one of the one or more reaction chambers is coupled to a microwave generator configured to provide microwave radiation to reactants within the at least one reaction chamber; and a controller. The controller is configured to control the one or more pumps and / or the one or more valves to adjust the transfer rate and amount of chemicals transferred from the one or more storage tanks to corresponding ones of the one or more reaction chambers, and to control the microwave generator to heat the reactants within at least one reaction chamber to a predetermined range of temperatures and to adjust the amount of microwave radiation provided to the at least one reaction chamber to maintain the temperature of the reactants within the predetermined range over a predetermined period. The washed fragments are disposed in a first reaction chamber of the one or more reaction chambers to contact a leaching solvent, and the first reaction chamber is among the at least one reaction chamber coupled to the microwave generator.

[0079] Clause 14. The system according to clause 13, wherein at least one of the one or more reaction chambers includes a stirrer configured to stir the reactants therein.

[0080] Clause 15. The system according to clause 13, wherein the crusher comprises a chamber configured to be maintained under vacuum and / or to have an inert atmosphere.

[0081] Clause 16. The system according to clause 13, wherein the leaching solvent includes sulfuric acid and an oxidizing agent.

[0082] Clause 17. The system according to clause 13, wherein the predetermined temperature range is 50°C to 90°C.

[0083] Clause 18. The system according to Clause 13, wherein the specified period is within the range of 10 seconds to 5 minutes.

[0084] Clause 19. The system according to Clause 13, wherein the leaching solvent has a pH within the range of 0 to 7.0.

[0085] Clause 20. The system according to Clause 13, wherein maintaining the temperature includes maintaining the temperature of the electrode dispersion within the range of 60°C to 80°C over a period within the range of 30 seconds to 5 minutes.

[0086] The foregoing description is provided to enable those skilled in the art to practice the various configurations described herein. Although the subject technology has been particularly described with reference to various drawings and configurations, it should be understood that these are for illustrative purposes only and should not be construed as limiting the scope of the subject technology.

[0087] Many other methods for implementing the subject technology may exist. The various functions and elements described herein may be divided differently from those shown without departing from the scope of the subject technology. Various modifications to these configurations will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other configurations. Therefore, many changes and modifications may be made to the subject technology by those skilled in the art without departing from the scope of the subject technology.

[0088] It is understood that the specific order or hierarchy of steps in the disclosed process is an example of an exemplary approach. It is understood that the specific order or hierarchy of the steps of the process may be rearranged based on design choices. Some steps may be executed simultaneously. The appended method claims present the elements of the various steps in a sample order and are not intended to be limited to the specific order or hierarchy presented.

[0089] As used herein, the term "about" preceding a quantity indicates a discrepancy with the quantity. The discrepancy can be caused by manufacturing tolerances or may be based on differences in measurement techniques. In some cases, the discrepancy can be up to 10% from the listed value. One of ordinary skill in the art will understand that the discrepancy of a particular quantity can be context-dependent and, therefore, for example, a discrepancy in dimensions at the microscale or nanoscale may differ from a discrepancy at the meter scale.

[0090] As used herein, the phrase "at least one of" preceding a series of items modifies the list as a whole, rather than each member of the list (i.e., each item), using the terms "and" or "or" to separate any of the items. The phrase "at least one of" does not require the selection of at least one of each of the listed items; rather, the phrase enables the meaning to include at least one of any one of the items, and / or at least one of any combination of the items, and / or at least one of each of the items. By way of example, the phrases "at least one of A, B, and C" or "at least one of A, B, or C" each refer to only A, only B, or only C, any combination of A, B, and C, and / or at least one of each of A, B, and C.

[0091] Terms such as "upper", "lower", "front", "rear", etc. used in this disclosure should be understood to refer to any reference frame, rather than the normal gravity reference frame. Therefore, the top surface, bottom surface, front surface, and rear surface can extend upwardly, downwardly, obliquely, or horizontally within the gravity reference frame.

[0092] Furthermore, as long as the terms "include", "have" or the like are used in the description or claims, such terms are intended to be inclusive in a manner similar to being construed as "comprise" when the term "comprise" is used as a transitional term in the claims.

[0093] The term "exemplary" is used herein to mean "an example, instance, or illustration". Any implementation form described herein as "exemplary" should not necessarily be construed as being more preferred or advantageous than other implementation forms.

[0094] References to elements in the singular are not intended to mean "only one and exactly one" unless specifically stated, but rather are intended to mean "one or more". Masculine pronouns (e.g., his) include feminine and neuter pronouns (e.g., her and its), and vice versa. The term "some" refers to one or more. Headings and subheadings in underline and / or italics are used for convenience only, do not limit the subject technology, and are not referred to in connection with the interpretation of the description of the subject technology. All those known to those skilled in the art or that will become known later, which are structurally and functionally equivalent to the various components described throughout this disclosure, are expressly incorporated herein by reference and are intended to be included in the subject technology. Furthermore, nothing disclosed herein is intended to be dedicated to the public, whether or not such disclosure is expressly recited in the above description.

Claims

**Claim 1** A method for obtaining a metal salt from a used lithium-ion (Li-ion) battery, comprising: separating an electrode portion from the pulverized Li-ion battery; contacting a leaching solvent with the separated electrode portion to form an electrode dispersion; heating a first dispersion to a temperature within the range of 50°C to 90°C by applying microwave radiation; maintaining the temperature of the first dispersion within the range of 50°C to 90°C for a period within the range of 10 seconds to 5 minutes by further applying microwave radiation to the heated first dispersion; filtering the electrode dispersion to obtain a metal. [[ / ]] **Claim 2** The method according to claim 1, wherein the metal comprises one of iron, aluminum, and copper. **Claim 3** The method according to claim 1 or 2, wherein the leaching solvent comprises sulfuric acid. **Claim 4** The method according to claim 3, wherein the leaching solvent further comprises an oxidizing agent. **Claim 5** The method according to claim 4, wherein the oxidizing agent is hydrogen peroxide. **Claim 6** The method according to any one of claims 1 to 5, wherein the leaching solvent has a pH within the range of 0 to 7.

0. **Claim 7** The method according to any one of claims 1 to 6, wherein heating the electrode dispersion further comprises stirring the electrode dispersion while applying the microwave radiation. **Claim 8** The method according to any one of claims 1 to 7, wherein maintaining the temperature of the electrode dispersion comprises controlling the application of the microwave radiation using a controller. **Claim 9** The method according to any one of claims 1 to 8, wherein heating the electrode dispersion comprises heating the electrode dispersion to a temperature within the range of 60°C to 80°C. **Claim 10** The method according to any one of claims 1 to 9, wherein maintaining the temperature comprises maintaining the temperature of the electrode dispersion within the range of 60°C to 80°C for a period within the range of 30 seconds to 5 minutes. **Claim 11** The method according to any one of claims 1 to 10, wherein the electrode portion comprises an electrode metal and a black mass comprising graphite and metal oxide. **Claim 12** The method according to claim 11, wherein filtering the electrode dispersion comprises filtering the electrode dispersion through a sieve to obtain graphite powder. **Claim 13** The method according to any one of claims 1 to 12, wherein heating the electrode dispersion further comprises continuously stirring the electrode dispersion while applying the microwave radiation.

14. The method according to any one of claims 1 to 13, wherein maintaining the temperature of the electrode dispersion further comprises continuously stirring the electrode dispersion while applying the microwave radiation.

15. A system for recycling a used lithium-ion battery, the system comprising a crusher configured to break the cells of the used lithium-ion battery into pieces; a washing chamber configured to wash the pieces; one or more storage tanks configured to store chemicals; one or more reaction chambers coupled to the one or more storage tanks via one or more pumps and valves, at least one of the one or more reaction chambers being coupled to a microwave generator configured to provide microwave radiation to reactants in the at least one reaction chamber; a controller, controlling the one or more pumps and / or the one or more valves to adjust the transfer rate and amount of chemicals transferred from the one or more storage tanks to corresponding ones of the one or more reaction chambers; controlling the microwave generator to heat the reactants in the at least one reaction chamber to a temperature within a predetermined range and to adjust the amount of microwave radiation provided to the at least one reaction chamber to maintain the temperature of the reactants within the predetermined range over a predetermined period of time; a system, wherein the washed pieces are disposed in a first reaction chamber of the one or more reaction chambers to be in contact with a leaching solvent, and the first reaction chamber is among the at least one reaction chamber coupled to the microwave generator.

16. The system according to claim 15, wherein at least one of the one or more reaction chambers includes a stirrer configured to stir the reactants therein.

17. The system according to claim 15 or 16, wherein the crusher comprises a chamber configured to be maintained under vacuum and / or to have an inert atmosphere.

18. The system according to any one of claims 15 to 17, wherein the leaching solvent contains sulfuric acid. **Claim 19** The system according to any one of claims 15 to 18, wherein the predetermined temperature range is 50°C to 90°C. **Claim 20** The system according to any one of claims 15 to 19, wherein the predetermined period is within the range of 10 seconds to 5 minutes. **Claim 21** The system according to any one of claims 15 to 20, wherein the leaching solvent has a pH within the range of 0 to 7.

0. **Claim 22** The system according to any one of claims 15 to 21, wherein maintaining the temperature includes maintaining the temperature of the electrode dispersion within the range of 60°C to 80°C for a period within the range of 30 seconds to 5 minutes.

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