Methods and systems for selectively extracting lithium from lithium-ion battery materials

Abstract

Methods and systems are provided for selectively extracting lithium from lithium ion batteries while avoiding the extraction of other metals from such batteries. The method involves contacting a sample including a lithium ion battery with an aqueous mixture of Br2 and a bromide reagent that dissociates in water to provide a bromide ion, and allowing the aqueous mixture to leach lithium ion from the sample as an aqueous solution of LiBr. LiBr is then recycled. For embodiments wherein the bromide reagent is HBr, hydrogen and bromine can be recovered as gases.

Description

METHODS AND SYSTEMS FOR SELECTIVELY EXTRACTING LITHIUM FROM LITHIUM-ION BATTERY MATERIALSCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 561,468. filed March 5, 2024, the disclosures of which are hereby incorporated by reference in their entireties.BACKGROUND

[0002] Hydrometallurgical recycling of lithium-ion batteries typically occurs under acidic, oxidative conditions using sulfuric acid and hydrogen peroxide reagents. These reagents are classified as oxidizers by the Occupational Safety and Health Administration, subject to unique transportation regulations. Moreover, these reagents tend to leach target products from the battery material at similar rates, resulting the performance of additional separation processes to isolate a particular target product, and reducing the efficacy and efficiency of the recycling scheme overall.SUMMARY

[0003] The present disclosure relates to methods of recycling materials from lithium ion batteries. In particular a means is disclosed of selectively separating lithium from other metals in lithium ion batteries.

[0004] Aspects of the present disclosure include methods in which a bromine reactant is contacted with spent lithium-ion battery7materials to isolate lithium products and enable circularity7and synergy with electrochemical chloralkali-adjacent processes, and systems for performing such methods.

[0005] Standard hydrometallurgical battery recycling processes employ extensive separation processes to isolate valuable elements (typically lithium, cobalt, nickel) from waste streams. Embodiments of the present disclosure contact a bromine reactant with commercially dominant cathode materials lithium nickel manganese cobalt oxide compound 811 (NMC811) and lithium- iron-phosphate (LFP) to selectively leach lithium therefrom, considerably simplifying recycling flowsheets.

[0006] A method is provided of selectively extracting lithium from lithium-ion battery materials, the method including providing a sample of lithium-ion battery materials, the sample including apositive electrode, contacting the sample with an aqueous mixture of Br2 and a bromide reagent that dissociates in water to provide a bromide ion, selectively leaching lithium ion from the sample, thereby forming an aqueous solution of LiBr, and separating the aqueous LiBr solution from the sample.

[0007] According to some embodiments, the bromide ion is provided in the form of a bromide salt. For some embodiments, the bromide salt is MBr, where M is an alkali cation. For some embodiments, the bromide salt is NaBr. For some embodiments the bromide ion is provided by an aqueous HBr solution. According to some embodiments, the LiBr solution is electrolytically processed to provide lithium metal, hydrogen gas, and bromine gas.

[0008] According to some embodiments, the positive electrode comprises a lithium ion intercalative material. According to some embodiments, the lithium ion intercalative material is selected from the group consisting of LiNMC, LiFP, LMO, and LCO. According to some embodiments, the Bn concentration in the aqueous mixture of B and bromide ion is between about 0.25 M and about 5M. According to some embodiments, concentration of the bromide reagent is between about 0.5M and about 10M.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Fig. 1 embodies a system and method for selectively extracting lithium from lithium ion battery materials.

[0010] Fig. 2 provides an embodiment wherein lithium ion is selectively extracted from 100 g / L LiNMC811 powder by mixing with a mixture of 1.6 M Br2 and 3.2 M NaBr.

[0011] Fig. 3 shows the effect of mixing 100 g / L LiNMC811 powder with 2M H2SO4.

[0012] Fig. 4 shows the effect of mixing 100 g / L LiNMC811 with a piranha solution of 2M H2SO4 and 15% H2O2.

[0013] Fig. 5 provides an embodiment wherein 100 g / L LiNMC811, pretreated with 1.6M Br2 and NaBn is treated with piranha solution of 2M H2SO4 and 15% H2O2.

[0014] Fig. 6 shows the results of treating 100 g / L LiNMC811 powder with IM HBr.

[0015] Fig. 7 shows the results of treating 100 g / L LiNMC811 powder with 2M HBr.

[0016] Fig. 8 shows the results of treating 100 g / L LiNMC811 with 0.5M HBr and 1.6M Bn.

[0017] Fig. 9 shows the results of treating 100 g / L LiNMC811 with IM HBr and 1.6M Bn.

[0018] Fig. 10 shows the results of treating 100 g / L LiNMC 811 with 2M HBr and 1.6M Bn.

[0019] Fig. 11 provides an embodiment wherein lithium ion is selectively extracted from 100 g / L LFP powder by mixing with a mixture of 1.6 M Bn and 3.2 M NaBr.

[0020] Fig. 12 shows the results of treating 100 g / L LFP powder with 2M H2SO4.DETAILED DESCRIPTIONDefinitions:

[0021] As used herein, a '‘bromine reactant” is an aqueous mixture of Br2 and a solute providing a dissolved bromide ion. In some embodiments, the Br2 is only partially dissolved. In some embodiments, the bromine reactant is provided by a solution of Br2 and bromide salt. In some such embodiments, the bromide salt is the bromide salt of an alkali metal. In some embodiments, the bromide ion is provided by HBr.

[0022] “NMC” is a generic term for lithium-intercalating mixed metal oxides having the general formula NixMnyCoi-x-yO2. The formal charge on the transition metal ions in NMC is +4. “LiNMC” is the lithium-intercalated form of NMC having the formula: LiNixMnyCoi-x-yO2. The formal charge on the transition metal ions in LiNMC is +3.

[0023] As used herein, “NMC81 1 ” refers to Nio 8Mno.1Coo.1O2.

[0024] As used herein, “LiNMC811” refers to LiNio.8Mno.1Coo.1O2.

[0025] As used herein, “LiFP” is lithium iron phosphate, LiFePO4.

[0026] As used herein, “LiMP” refers to any of a number of olivine compounds having structural formula LiMPO4, for which M is selected from the group consisting of Fe, Co, Mn, and Ti.

[0027] As used herein, “LMO” refers to lithium manganese oxide (LiMn2O4 or Li2MnOs).

[0028] As used herein, “LCO” is lithium cobalt oxide, LiCoCh.

[0029] A “lithium mineral” is a mineral, for example an ore, the composition of which includes lithium.

[0030] '‘Leaching efficiency” of a metal from a metal composition, for example a batten material, is defined as the amount of metal collected in supernatant following treatment of the battery material with a leaching solution divided by the amount of metal initially present in the battery material. For the results reported herein, the amounts of the various metals are determined by inductively coupled plasma spectroscopy (ICP). However, a person of ordinary skill in analytical methods w ould understand that other methods can also be used to determine these amounts.

[0031] A “positive electrode” of a battery functions as a cathode during discharge and as an anode during charging. Herein, if an electrode is referred to as a “cathode,” without specifying whether it functions in a process that is galvanic or electrolytic, then it is a “positive electrode.”

[0032] A “negative electrode” of a battery7functions as an anode during discharge and as a cathode during charging. Herein, if an electrode is referred to as a “anode,” without specifying whether it functions in a process that is galvanic or electrolytic, then it is a “negative electrode.”

[0033] Some embodiments of the present disclosure are directed to methods including leaching lithium products from lithium-ion battery materials. In some embodiments, the lithium-ion battery materials are spent lithium-ion battery materials. In some embodiments, the lithium-ion battery materials include cathode materials. In some embodiments, the lithium-ion battery materials include a lithium nickel manganese cobalt oxide compound (LiNMC). In some embodiments, the LiNMC includes LiNMC811. In some embodiments, the lithium-ion batten materials include lithium-iron-phosphate (LFP).

[0034] In some embodiments, the leaching of the lithium product includes contacting an amount of lithium-ion battery material or lithium mineral with a concentration of bromine reactant to form a reaction medium. In some embodiments, the leaching of the lithium product includes contacting one or more LiNMCs with a concentration of a bromine reactant. In some embodiments, the leaching of the lithium product includes contacting a concentration of LFP with a concentration of a bromine reactant. In some embodiments, the bromine reactant includes a bromide salt. In some such embodiments, the bromide salt is the bromide salt of an alkali metal. In some embodiments, the bromine reagent includes HBr.

[0035] In some embodiments, a product stream is isolated that includes one or more lithium products. In some embodiments, the product stream is isolated from the reaction medium that includes bromine reactant treated battery materials or lithium minerals. In some embodiments, the reaction medium includes, after removing Li from the bromine reactant treated battery materials, residual concentrations of Ni, Mn, Co, O and Na. In some embodiments, leaching of lithium with bromine reactant can be applied to lithium minerals processing in addition to recycling.

[0036] Without being bound by theory, it is hypothesized that the following reactions are used to produce the lithium product for the case of LiNMC:Aqueous bromine reacts with bromide ion to give the tribromide ion, Bra’:Br2(aq) + Br~(aq) -> Br (1)LiNMC is formally oxidized by the tribromide ion to release Li according to:2LiNMC + Br2(aq) ^ 2NMC + 2Li++ 2Br~ (2)Analogous equations are believed to hold for other battery materials.

[0037] In some embodiments, for which the bromide ion is supplied by hydrobromic acid, incorporation of bromine regeneration from hydrobromic acid through a chloralkali -adjacent process is used to also generate a hydrogen product which can be commoditized. In some embodiments, the hydrogen and bromine products includes hydrogen gas.

[0038] An embodiment of a system and method for extracting lithium ion from lithium ion battery materials is provided in Fig. 1. First, a source of lithium-ion battery materials 10 is contacted with a bromine reactant so that lithium ion is leached from the batten' materials to form an aqueous solution of LiBr 20, which is then recycled 30. For embodiments where the bromine reactant includes HBr, hydrogen and bromine can be electrolytically recovered as a gas 40.

[0039] The leaching efficiency of Li compared to other metals with bromine reagents is compared with other leachants in Figs. 2-12. In Figs. 2-10, Li results correspond to hollow circles (o), Co to solid circles (•), Ni to hollow diamonds (0), and Mn to solid diamonds (♦). In Figs. 11 and 12, hollow circles (o) correspond to Li results and solid circles (•) to results for Fe. For all of these figures, the amount of battery material (LiNMC or LFP) was kept constant at 100 g / L.

[0040] Referring now to FIG. 2, an exemplary embodiment of the present disclosure demonstrates leaching of a lithium product from LiNMC811 using Br2. In this embodiment, 100 g / L of a LiNMC811 pow der is mixed with an aqueous composition of 1.6 M Br2 and 3.2 M NaBr. The top curve with hollow' circles corresponds to Br2 leaching efficiency of Li. The bottom curv e corresponds to the leaching efficiency of the remaining metals, i.e. Co, Mn, and Ni. For the embodiment of Fig. 2 leaching was selective for lithium while leaving Co, Mn, and Ni in the solid phase.

[0041] This selectivity for leaching lithium is to be contrasted with other leachants, e.g., H2SO4 and H2SO4 + H2O2 solutions, which have been shown to leach metals indiscriminately. For example, as shown in Fig. 3, treatment of 100 g / L LiNMC811 powder with 2M H2SO4 shows poor overall efficiency, and only modest discrimination. And. as shown in Fig. 4. while treatment of 100 g / L NMC811 with piranha solution (2M H2SO4 plus 15% H2O2) shows excellent leaching efficiency, it show's little if any discrimination.

[0042] Referring now' to FIG. 5, a 100 g / L sample pre-treated with bromine reactant was then treated with piranha solution. Leaching of Bn pre-leached LiNMC811 had faster kinetics than was found for LiNMC81 1 pow der directly in piranha. Lower concentrations of Bn with low'er pulp densities (solid content) also had fast kinetics (typical pulp densities 100 g / L).

[0043] Referring now' to Figs. 6 and 7, leaching was tested with solutions of 1 M HBr and 2 M HBr, respectively. Leaching results with HBr showed similar leaching behavior to sulfuric acid (see, again. FIG. 3), with enhanced leaching efficiency at 2M HBr (Fig. 7) compared to IM HBr (Fig. 6), but with no evident effect on leaching selectivity. Again, without being bound by theory, this is consistent with a kinetics mechanism involving the formation of B " (equations (1) and (2)).

[0044] Likewise consistent with this mechanism are the results of Figs. 8 - 10, which show the effect of increasing HBr concentration at constant concentration of Br . For these figures the Br2 concentration is kept constant at 1.6 M. The concentrations of HBr are 0.5M for Fig. 8, IM for Fig. 9, and 2M for Fig. 10. Based on these results, it is evident that if the HBr concentration is increased beyond a certain point, selectivity decreases, i.e. the leaching approaches the leaching observed for H2SO4.

[0045] Referring now to FIG. 11, highly efficient and highly selective leaching of lithium products from 100 g / L LFP is found for a bromine reactant of 1.6 M Br2 and 3.2M NaBr. For comparison, Fig. 12 shows the leaching behavior of 100 g / L LFP in the presence of 2M H2SO4. Under the conditions of Fig. 12, leaching is highly efficient, but shows very little selectivity.

[0046] Based on the results of Figs. 2-12, it is evident that bromine reactants comprising Br2 and Br are highly efficient and highly selective at releasing lithium ion compared to transition metals for the Li-intercalative transition metal oxides LiNMC and LFP. Similar selectivity from other such Li-intercalative transition metal oxides, including LiMP. LMO, and LCO is anticipated.

[0047] Methods and systems of the present disclosure are directed to the selective generation of lithium products from lithium-ion battery materials via contact with and leaching by bromine reactant. In traditional hydrometallurgical lithium-ion battery recycling, hydrogen peroxide is an extensively used reagent. Utilizing bromine reactant as a leachant can replace hydrogen peroxide while providing highly specific leaching of lithium from the other metals, and further allows Br2 to be regenerated on-site. Hydrogen co-generated with bromine from hydrobromic acid can also be treated as a commodity or an input in reductive roasting operations for primary and secondary materials processing. In addition, bromine reactant selectivity for lithium considerably simplifies hydrometallurgical recycling flowsheets and reduces capital expenditures associated with lithium recovery.

[0048] Although the invention has been described and illustrated with respect to exemplary embodiments thereof, it should be understood by those skilled in the art that the foregoing and various other changes, omissions and additions may be made therein and thereto, without parting from the spirit and scope of the present invention.

Claims

WHAT IS CLAIMED IS:

1. A method of selectively extracting lithium from lithium-ion battery materials, comprising: providing a sample of lithium-ion battery materials, the sample including a positive electrode; contacting the sample with an aqueous mixture of Br2 and a bromide reagent that dissociates in water to provide a bromide ion; selectively leaching lithium ion from the sample, thereby forming an aqueous solution of LiBr; and separating the aqueous LiBr solution from the sample.

2. The method of claim 1, wherein the bromide ion is provided in the form of a bromide salt.

3. The method of claim 2, wherein the bromide salt is MBr, where M is an alkali cation.

4. The method of claim 3, wherein the bromide salt is NaBr.

5. The method of claim 1. wherein the bromide ion is provided by an aqueous HBr solution.

6. The method of claim 5, wherein the LiBr solution is electrolytically processed to provide lithium metal, hydrogen gas, and bromine gas.

7. The method of any one of claims 1 to 6, wherein the positive electrode comprises a lithium ion intercalative material.

8. The method of claim 7, wherein the lithium ion intercalative material is selected from the group consisting of LiNMC, LFP, LMO, and LCO.

9. The method of any one of claims 1-8, wherein the Br2 concentration in the aqueous mixture of Br2 and bromide ion is between about 0.25 M and about 5M.

10. The method of any one of claims 1-9, wherein the concentration of the bromide reagent is between about 0.5M and about 10M.

11. A system for selectively extracting lithium from lithium-ion battery materials, comprising: a source of feedstock including lithium-ion battery materials, the lithium-ion battery materials including a positive electrode;a source of an aqueous mixture of Br2 and a bromide reagent that dissociates in water to provide a bromide ion; a reactor including one or more inlets, and one or more outlets, the inlets being in communication with the source of the feedstock and the source of the aqueous mixture; a product stream in fluid communication with the outlets, the product stream including a concentration of LiBr formed from leaching lithium ions from the lithium-ion battery materials.

12. The system according to claim 11, wherein the bromide reagent is a bromide salt.

13. The system according to claim 12, wherein the bromide salt is MBr, where M is an alkali cation.

14. The system according to claim 12, wherein the bromide salt is NaBr.

15. The system according to claim 11, wherein the bromide reagent is an aqueous HBr solution.

16. The system according to claim 15. further including a hydrogen product stream in fluid communication with one of the one or more outlets, the hydrogen product stream including a concentration of hydrogen gas.

17. The system of any one of claims 11 to 16, wherein the positive electrode comprises a lithium ion intercalative material.

18. The system of claim 17, wherein the intercalative material is selected from the group consisting of LiNMC, LFP, LMO. and LCO.

19. The system of any one of claims 11 to 18, wherein the Br2 concentration in the aqueous mixture of Br2 and bromide ion is between about 0.25 M and about 5M.

20. The method of any one of claims 11 to 19, wherein the concentration of the bromide reagent is between about 0.5M and about 10M.

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