METHOD AND SYSTEM FOR RECYCLING LITHIUM ION BATTERIES USING ELECTROCHEMICAL LITHIUM ION PURIFICATION
20240003019 ยท 2024-01-04
Inventors
- Xin Gao (Lexington, KY, US)
- Ayokunle Omosebi (Lexington, KY, US)
- Aron Patrick (Louisville, KY, US)
- Kunlei Liu (Lexington, KY)
Cpc classification
International classification
Abstract
A method of recycling lithium-ion batteries includes steps of: roasting black mass from lithium-ion batteries to produce a reduced black mass, conducting simultaneous aqueous leaching and wet magnetic separation of the reduced black mass for (a) extracting soluble lithium species and (b) enriching metallic NiCo and subjecting the extracted soluble lithium species to electrochemical lithium ion purification. A system for recycling lithium ion batteries includes a roaster, an aqueous leaching and wet magnetic separator and an electrochemical lithium ion separator.
Claims
1. A method of recycling lithium-ion batteries, comprising: roasting black mass from lithium-ion batteries to produce a reduced black mass; conducting simultaneous aqueous leaching and wet magnetic separation of the reduced black mass for (a) extracting soluble lithium species and (b) enriching metallic NiCo; and subjecting the extracted soluble lithium species to electrochemical lithium ion purification.
2. The method of claim 1, further including producing hydrogen gas during the electrochemical lithium ion purification.
3. The method of claim 2, further including using the hydrogen gas produced during the electrochemical lithium ion purification to perform the roasting of the black mass.
4. The method of claim 1, wherein the subjecting of the extracted soluble lithium species to electrochemical lithium ion purification includes (a) generating hydroxide ions and hydrogen gas at a cathode in a cathode compartment of a flow cell on a first side of an ion exchange membrane, (b) generating oxygen gas at an anode in an anode compartment of the flow cell, (c) allowing passage of lithium ions from the extracted soluble lithium species through the ion exchange membrane from the anode compartment to the cathode compartment to balance out the hydroxide ions generated at the cathode and (d) recovering purified lithium hydroxide from the flow cell.
5. The method of claim 4, further including using the hydrogen gas produced during the electrochemical lithium ion purification to perform the roasting of the black mass.
6. The method of claim 5, further including crushing lithium ion batteries to prepare the black mass for roasting.
7. The method of claim 6, further including applying a voltage of about 2.5-6.5 volts at a current density of about 20-1150 mA/cm.sup.2 across the anode and the cathode during the electrochemical lithium ion purification.
8. The method of claim 7, further including contacting lithium hydroxide from the flow cell with carbon dioxide in a membrane contactor to produce lithium carbonate.
9. A system for recycling lithium ion batteries, comprising: a roaster adapted for reductive roasting of a lithium ion battery black mass and producing a reduced black mass; an aqueous leaching and wet magnetic separator, downstream from the roaster, adapted for (a) extracting soluble lithium species and (b) enriching metallic NiCo from the reduced black mass; and an electrochemical lithium ion separator, downstream from the aqueous leaching and wet magnetic separator, adapted for purifying lithium hydroxide from the extracted lithium species.
10. The system of claim 9, further including a shredder adapted for shedding the lithium ion batteries and making the lithium ion battery black mass delivered to the roaster.
11. The system of claim 10, wherein the roaster is a rotary reactor.
12. The system of claim 11, wherein the electrochemical purifier includes a flow cell having an anode compartment, a cathode compartment, an ion exchange membrane separating the anode compartment from the cathode compartment, an anode in the anode compartment and a cathode in the cathode compartment.
13. The system of claim 12, further including a voltage source adapted to supply a voltage potential across the anode and the cathode.
14. The system of claim 13, wherein the voltage source is adapted to supply a voltage of about 2.5-6.5 volts at a current density of about 20-1150 mA/cm.sup.2 across the anode and the cathode during the electrochemical lithium ion purification.
15. The system of claim 14, wherein the anode is a dimensionally stable anode.
16. The system of claim 14, wherein the anode is made from titanium.
17. The system of claim 16, wherein the cathode is made from a material selected from a group consisting of graphite, iron, nickel, iron-nickel alloy, nickel chromium alloy or combinations thereof.
18. The system of claim 14, wherein the electrochemical lithium ion separator further includes a membrane contactor adapted for contacting the purified lithium hydroxide received from the flow cell with carbon dioxide and converting the purified lithium hydroxide to lithium carbonate.
19. The system of claim 12, wherein the electrochemical lithium ion separator further includes a membrane contactor adapted for contacting the purified lithium hydroxide received from the flow cell with carbon dioxide and converting the purified lithium hydroxide to lithium carbonate.
20. The system of claim 9, wherein the electrochemical lithium ion separator further includes a flow cell and a membrane contactor adapted for contacting the purified lithium hydroxide received from the flow cell with carbon dioxide and converting the purified lithium hydroxide to lithium carbonate.
Description
BRIEF DESCRIPTION OF THE DRAWING FIGURES
[0018] The accompanying drawing figures incorporated herein and forming a part of the specification, illustrate certain aspects of the method and together with the description serve to explain certain principles thereof.
[0019]
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[0022]
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[0029]
[0030] Reference will now be made in detail to the present preferred embodiments of the method.
DETAILED DESCRIPTION
[0031] As set forth in
[0032] The roaster 12 is adapted for reductive roasting of a lithium ion battery black mass to produce a reduced black mass. For purposes of this document, black mass refers to shredded or crushed whole lithium ion batteries, including active materials from the cathode, graphite from the anode, Al and Cu from the current collectors, battery electrolyte, plastic separator, plastic and iron casings, etc. The high-value species like Co, Ni, and Li come from active materials like lithium cobalt oxide (LCO), lithium manganese nickel cobalt oxide (MNC), lithium nickel cobalt aluminum oxide (NCA), lithium iron phosphate (LPO), etc. Under such a scenario, to enrich these high-value metals, thermal and/or chemical treating black mass become the essential steps together with the additional separation and purification.
[0033] The atmosphere-assisted roasting of the black mass is one of the thermal-chemical processes to decompose the active materials under the reducing atmosphere toward forming H.sub.2O soluble Li salts and metal oxides or metallic metal.
[0034] The aqueous leaching and wet magnetic separator 14 is adapted for (a) extracting soluble lithium species and (b) enriching metallic NiCo from the reduced black mass received from the roaster 12. Eriez wet drum separators may be used for this purpose. One of the key results from phase and speciation analysis shows that approximately 90% of NiCo solids can be recovered with the purity of about 90%; however, the dissolved anions like AlO.sub.2, F, PO.sub.4.sup.3, and Si.sub.4O.sub.8(OH).sub.44 in the H.sub.2O leachate significantly impact the quality of Li.sub.2CO.sub.3 even though around 80% Li recovery can be achieved.
[0035] The electrochemical lithium ion separator (ELIS) 16 is adapted for purifying lithium hydroxide or lithium carbonate from the extracted lithium species received from the aqueous leaching and wet magnetic separator 14. Lithium hydroxide and lithium carbonate are typical precursors for producing cathode active material at an industrial scale. As shown in
[0036] An anode 26 is provided in the anode compartment 20 and a cathode 28 is provided in the cathode compartment 22. The anode 26 may be a dimensionally stable anode and may be made from any appropriate non-corrosive material including, but not necessarily limited to titanium. The cathode 28 may be made from any appropriate material including, but not necessarily limited to, graphite, iron, nickel, iron-nickel alloy, nickel-chromium alloy or combinations thereof. The system 10 also includes a voltage source 30 adapted to supply a voltage potential across the anode 26 and the cathode 28. Further, the voltage source 30 may be adapted to supply a voltage of about 2.5-6.5 volts at a current density of about 20-1150 mA/cm.sup.2 across the anode 26 and the cathode 28 during the electrochemical lithium ion purification.
[0037] Due to the use of the cation-selective membrane 24, only Li.sup.+ in the anolyte loop (solid action arrows) can pass through the membrane under the electrical field to balance the OH.sup. in the catholyte loop (dashed action arrows). Therefore, the electrochemical lithium ion separator 16 produces a purified LiOH salt. In addition, the co-produced hydrogen gas (H.sub.2) can be used to fuel the roaster 12 and lower the fuel or energy requirement of the upstream roasting process.
[0038] In an alternative embodiment of the system 10, the electrochemical lithium ion separator 16 further includes a membrane contactor 32, of a type known in the art, that is adapted for contacting the purified lithium hydroxide received from the flow cell 18 with carbon dioxide and converting the purified lithium hydroxide to lithium carbonate. Such a membrane contactor 32 includes a shell side and a lumen side. Liquid containing Li ions can be fed into either the shell or lumen side. For example, if liquid enters into the lumen side, a CO.sub.2 stream will be fed into the shell side.
[0039]
[0040] The roaster 12 in
[0041] In some particularly useful embodiments, the shredder 11 and the roaster 12 are mounted on vehiclesV (e.g. truck beds or tractor trailers) to allow them the necessary mobility to be taken to the site or source of the lithium battery supply (battery collection sites). The on-site crushing/shredding and reduction mitigates any thermal runaway that may occur during transporting the end of life lithium ion batteries and lift transportation limits of the hazardous materials from the lithium ion batteries. For example, in Box A of
[0042] Centralized Metal and Graphite Recovery ProcessSince the metallic solids such Ni and Co from the lithium ion batteries are typically magnetic at size less than 15 m, and LiOH and Li.sub.2CO.sub.3 (for this technology) are H.sub.2O soluble, wet sifting and magnetic separation in Boxes B and C are the option to separate the active materials and magnetic alloy and non-magnetic graphite, remaining Fe, Cu, and Al from Li-containing H.sub.2O leachate. For instance, the wet sifting along with vibration will be used to remove the large solids like Fe, Cu and Al based upon the size exclusion working principle in Box B. Subsequently, the magnetic alloy, e.g., NiCo when using NCA-based black mass, NiCoMnO when using MNC-based black mass, Co when using LCO-based black mass, and/or Fe when using LPF-based black mass, is recovered from a wet magnetic separator in Box C. To upgrade either LiOH or Li.sub.2CO.sub.3 by filtering the additional anions like AlO.sub.2.sup., F.sup., PO.sub.4.sup.3, and Si.sub.4O.sub.8(OH).sub.4.sup.4, Li-containing H.sub.2O leachate is fed into an electrochemical Li-ion separator (ELIS) 16, in which only Li cations pass through the cation-exchange membrane 24 to produce either LiOH or Li.sub.2CO.sub.3 liquor with CO.sub.2 resources without foreign chemicals added. Herein, the co-generated H.sub.2 gas from the ELIP 16 can be a saleable commodity. The Li-removed H.sub.2O will be recycled to extract H.sub.2O soluble Li salts from the reduced solids in Box B.
[0043] Summarizing, the system 10 and method disclosed herein are characterized by a number of significant advantages over prior art approached for lithium ion battery recycling. These include, but are not necessarily limited to: [0044] 1) Process intensification and simplicity: using one device (or one step) to offer LiOH or Li.sub.2CO.sub.3 production with no needs of chemicals, pressure, or heating. [0045] 2) H.sub.2 utilization: creating an eco-friendly pathway to reduce the heating requirement of roasting process while mitigating carbon emission. [0046] 3) H.sub.2O conservation: reusing Li-extracted H.sub.2O leachate to prepare the reduced black mass slurry.
Experimental
B1. Pilot-Scale Process Design
C. Data Provided to Support Readiness of Invention
C1. Pristine Black Mass
[0047] Peak assignments of the X-ray powder diffraction (XRD) pattern in
C2. Preparing Lithium Containing H2O Leachate
C2.1. Preparing Reduced Black Mass Using Carbothermic Roasting
[0048] 12.089 g of the pristine black mass on a quartz boat was roasted using a Carbolite Gero tube furnace under the N.sub.2 atmosphere at 1 L min.sup.1. The roasting process started from room temperature to 700 C. at the ramping rate of 20 C. min.sup.1, followed by an isothermal step for 2 hours. Once the process was completed, the black mass, named reduced black mass in the following text, was characterized using XRD to validate the effectiveness of carbothermic reductions for producing the Li salts and magnetic NiCo.
C2.2. Li Extraction Process
[0049] 8.458 g of the reduced black mass was placed into deionized water at the liquid to solid weight ratio of 50 in a high-density polyethylene (HDPE) bottle. Sonication was performed using a typical water bath sonicator for 5 min to enhance the Li extraction. Solid-liquid separation was conducted using a typical vacuum-assisted separator. The resulting Li-containing liquid with additional species, named H.sub.2O leachate in the following text, was stored in a HDPE bottle before further uses. 351.100 g of H.sub.2O leachate was recovered after the solid-liquid separation, and characterized in terms of pH, conductivity, and alkalinity. Approximately 50 g of H.sub.2O leachate (without any treatment) was directly dried in a Thermo Scientific oven at 105 C. for about 24 hours to recover Li salts for element analysis by EDS. Finally, the solids collected from the solid-liquid separation (not from drying the H.sub.2O leachate), named Li extracted black mass in the following text, were dried in a Thermo Scientific oven at 105 C. for evidencing the Li removal by XRD.
C2.3. Identifying Dissolved Species in H2O Leachate
[0050] As depicted in the XRD patterns of
C3. Case Study of Li2CO3 Production
C3.1. Conditions to Operate ELIS
[0051] Identifying the dissolved species suggests that size-exclusion-based filtrations like nanofiltration and reverse osmosis may not achieve the separation of Li.sup.t and CO.sub.3.sup.2 from additional anions. Moreover, the conventional Li extraction from Li brine is a multistep process including the use of holding tanks, heating equipment, and chemicals for pH adjustment and solids settling. To resolve such an issue while simplifying the process, using the ELIS is proposed to solely purify Li.sup.t. Because of the cation selectivity of the membrane, Li.sup.t is the only species that can pass through the membrane from the anode to cathode.
[0052] 51.442 g of the H.sub.2O leachate as anolyte and 73.793 g of 0.12 M Li.sub.2CO.sub.3 as catholyte were continuously circulated in the ELIS at 15 mL min.sup.1 and at 0.5 A for 1 hour. Once the operation was completed, the catholyte was dried in a Thermo Scientific oven to recover Li salts for EDS and XRD analysis to validate the feasibility of ELIS for purifying Li.
C3.2. Solids Characterization
[0053] To validate our understanding, the solids after drying the catholyte were analyzed. The EDS spectrum of
C4. Case Study of LiOH Production
C4.1. Conditions to Operate ELIS
[0054] 96.523 g of the H.sub.2O leachate as anolyte and 94.465 g of 0.056 M LiOH as catholyte were continuously circulated at 15 mL min.sup.1 and 0.25 A for approximate 2 hours. Once the operation was completed, the resulting anolyte and catholyte were characterized to look at changes in the pH, conductivity, and alkalinity caused by the Li transport across the membrane in addition to characterizing the solids by EDS and XRD. (Please note that to prevent the formation of Li.sub.2CO.sub.3 via CO.sub.2 reacting with LiOH, the drying process was performed under vacuum.)
C4.2. Liquid and Solids Characterization
[0055] Decreased anolyte values and increased catholyte values in Table 2 mean that Li.sup.+ has been moved from the anolyte to catholyte loops of the ELIS during water electrolysis. Briefly, decreased anolyte pH is caused by consuming OH.sup. toward O.sub.2 evolution via 4OH.sup.O.sub.2+2H.sub.2O+4e.sup.; and on the other hand, increased catholyte pH is accounted for by H.sub.2 evolution via 2H.sub.2O+2e.sup.H.sub.2+2OH.sup., subsequently leaving OH.sup. in the catholyte. Due to the charge neutrality of a solution and use of cation-selective membrane, Li.sup.+ is the only species that can be moved through the membrane to balance the OH.sup.. As a result, high-quality of LiOH salt will be produced after H.sub.2O is removed from the catholyte.
TABLE-US-00002 TABLE 2 Changes in conductivity, pH, and alkalinity of the anolyte and catholyte before and after Li purification using the ELIS. Sample Conductivity/mS pH Alkalinity/M Starting Anolyte 18.6 12.66 0.0949 Catholyte 17.3 12.57 0.0556 Ending Anolyte 2.46 7.37 0.0165 Catholyte 25.3 12.8 0.1258
[0056] To examine the quality of LiOH salts, EDS and XRD analyses were carried out for the solids after removing H.sub.2O from the catholyte. In comparison to
[0057] Each of the following terms written in singular grammatical form: a, an, and the, as used herein, means at least one, or one or more. Use of the phrase One or more herein does not alter this intended meaning of a, an, or the. Accordingly, the terms a, an, and the, as used herein, may also refer to, and encompass, a plurality of the stated entity or object, unless otherwise specifically defined or stated herein, or, unless the context clearly dictates otherwise.
[0058] Each of the following terms: includes, including, has, having, comprises, and comprising, and, their linguistic/grammatical variants, derivatives, or/and conjugates, as used herein, means including, but not limited to, and is to be taken as specifying the stated component(s), feature(s), characteristic(s), parameter(s), integer(s), or step(s), and does not preclude addition of one or more additional component(s), feature(s), characteristic(s), parameter(s), integer(s), step(s), or groups thereof.
[0059] The phrase consisting of, as used herein, is closed-ended and excludes any element, step, or ingredient not specifically mentioned. The phrase consisting essentially of, as used herein, is a semi-closed term indicating that an item is limited to the components specified and those that do not materially affect the basic and novel characteristic(s) of what is specified.
[0060] It is to be fully understood that certain aspects, characteristics, and features, of the system and method, which are, for clarity, illustratively described and presented in the context or format of a plurality of separate embodiments, may also be illustratively described and presented in any suitable combination or sub-combination in the context or format of a single embodiment. Conversely, various aspects, characteristics, and features, of the method which are illustratively described and presented in combination or sub-combination in the context or format of a single embodiment may also be illustratively described and presented in the context or format of a plurality of separate embodiments.
[0061] Although the system and method of recycling lithium ion batteries have been illustratively described and presented by way of specific exemplary embodiments, and examples thereof, it is evident that many alternatives, modifications, or/and variations, thereof, will be apparent to those skilled in the art. Accordingly, it is intended that all such alternatives, modifications, or/and variations, fall within the spirit of, and are encompassed by, the broad scope of the appended claims.