Self-sufficient biohydrometallurgy recycling of spent battery electrode materials
Patent Information
- Application Number
- PCT/US2026/019944
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-03-21
- Filing Date
- 2026-03-19
- Publication Date
- 2026-09-24
Smart Images
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Abstract
Description
[0001] Docket No. BCOT-OIO-WOI BC2025.014.wan
[0002] SELF-SUFFICIENT BIOHYDROMETALLURGY RECYCLING OF SPENT BATTERY ELECTRODE MATERIALS
[0003] CROSS-REFERENCE TO RELATED APPLICATION This Application claims the benefit of and priority from U.S. Application No.
[0004] 63 / 775,736, filed on March 21, 2025. The entire teaching of the above application is incorporated herein by reference.
[0005] GOVERNMENT SUPPORT
[0006] This invention was made with government support under 2342967 awarded by the National Science Foundation. The government has certain rights in the invention.
[0007] BACKGROUND
[0008] The continuous demand for lithium-ion batteries (LIB) in consumer products and electric vehicles has raised concerns about their environmental impact when not disposed of properly.
[0009] Recycling efforts that center on recovering metals from cathodes can reduce LIB production costs and address global supply chain vulnerabilities. LIB recycling technology has grown significantly in the last decade, including simple pyrometallurgy (PM) methods that are highly energy intensive and can produce toxic by-products such as hydrogen fluoride.
[0010] Alternative methodologies such as direct recycling (DR) or hydrometallurgy (HM) have been developed that are inherently greener than the PM methods, but present their own drawbacks.
[0011] DR requires extensive manual labor for cell dismantling along with individual cell diagnostics, limiting prospects for large scale implementations. The HM process requires large volumes of strong acids and reductants.
[0012] To lower costs and lessen the environmental impact of LIB, it is critical to develop methods for recovering heavy metals such as nickel, manganese, and cobalt, as well as lithium, from the cathode material of spent LIB. While this goal can be achieved through the aforementioned processes, the need exists for a self-sustainedDocket No. BCOT-OIO-WOI BC2025.014.wan -2-
[0013] approach to recycle valuable materials from spent batteries without the drawbacks discussed above.
[0014] SUMMARY
[0015] To meet the need set out above, a method is provided for recovering one or more metals from a spent lithium-ion battery (LIB). The method includes the steps of inoculating an iron-oxidizing acidophilic bacteria into a medium that contains a source of magnesium, a source of potassium, a source of phosphate, a source of calcium, a source of iron, and, optionally, a source of nitrogen, to form an inoculant, the source of iron including metallic Fe; acidifying the inoculant to a pH lower than 4, preferably lower than 3, and more preferably 1 to 2; culturing the acidified inoculant to form a leaching solution, whereby the metallic Fe is oxidized to Fe3+; mixing a spent LIB material with the leaching solution to form a mixture, the spent LIB material containing one or more metals; incubating the mixture until the one or more metals are solubilized to obtain a pregnant leaching mixture; and recovering the one or more metals from the pregnant leaching mixture.
[0016] Also disclosed is a composition for recovering metals from a spent LIB in which the composition contains an iron-oxidizing acidophilic bacterium and a medium containing a source of magnesium, a source of potassium, a source of phosphate, a source of calcium, a source of iron that includes metallic Fe, and, optionally, a source of nitrogen, and a pH of the composition is 1 to 3.
[0017] Further provided is a method of culturing an iron- oxidizing acidophilic bacterium. The method includes the steps of inoculating the iron-oxidizing acidophilic bacterium into a medium that includes a source of magnesium, a source of potassium, a source of phosphate, a source of calcium, a source of iron that contains metallic Fe and, optionally, a source of nitrogen; acidifying the inoculant to a pH lower than 4, preferably lower than 3, and more preferably 1 to 2; and incubating the acidified inoculant at 20°C to 35°C, preferably at 30°C,
[0018] Also within the scope of the invention is a method for producing a composition for recovering metals from a spent LIB, the method carried out by inoculating an iron-oxidizing acidophilic bacteria into a medium that contains a source of magnesium, a source of potassium, a source of phosphate, a source of
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[0020] calcium, a source of iron, and, optionally, a source of nitrogen, to form an inoculant, the source of iron including metallic Fe; acidifying the inoculant to a pH lower than 4, preferably lower than 3, and more preferably 1 to 2; and culturing the acidified inoculant to form a leaching solution, whereby the metallic Fe is oxidized to Fe3+and a concentration of Fe3+in the composition is at least 1 g / L, preferably at least 2 g / L, and more preferably 3 g / L to 6 g / L.
[0021] Finally, a method is disclosed for recycling a spent LIB by grinding the spent LIB into a powder, mixing it with the above-described composition, and recovering metals from the spent LIB.
[0022] The details of one or more embodiments of the invention are set forth in the drawings and description below. Other features, objects, and advantages of the invention will be apparent from the description, from the drawing, and from the claims. All references cited herein are hereby incorporated by reference in their entirety.
[0023] BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The invention description below refers to the accompanying drawings.
[0025] Fig. 1 shows a generalized metal recovery strategy: hydrometallurgy, biohydrometallurgy, and the self- sufficient biohydrometallurgy approach of the invention.
[0026] Fig. 2A are plots of Fe2+concentration (squares), Fe3+concentration, (triangles), and pH (circles) versus culturing days of M9K-Fe-H2SO4 leading up to the stationary phase.
[0027] Fig. 2B are plots of Fe2+concentration (squares), Fe3+concentration (triangles), and pH (circles) versus culturing days of M9K-SS-H2SO4 leading up to the stationary phase.
[0028] Fig. 2C are plots of Fe2+concentration (stars), Fe3+concentration (triangles), and pH (diamonds) versus culturing days of M9K-Fe-HCl leading up to the stationary phase.
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[0030] Fig. 2D are plots of Fe2+concentration (stars), Fe3+concentration (triangles), and pH (diamonds) versus culturing days of M9K-SS-HC1 leading up to the stationary phase.
[0031] Fig. 3A are plots of Fe3+concentration versus days for non-inoculated (control) medium c-M9K-Fe-H2SO4 (triangles) and C-M9K-SS-H2SO4 (pentagons).
[0032] Fig. 3B are plots of Fe3+concentration versus days for non-inoculated (control) medium c-M9K-Fe-HCl (triangles) and C-M9K-SS-HC1 (pentagons).
[0033] Fig. 4 are plots of Fe2+concentration (circles), Fe3+concentration (squares), and pH (diamonds) versus culturing days in M9K-FS in which FeSO4 is the main fuel source.
[0034] Fig. 5 shows XRD trace (intensity versus 29 degree) of pristine NMC622 cathode powder. (003) peak, (006 / 102) peak splitting, and (108 / 110) peak splitting are indications of well-ordered structure. AU = arbitrary units.
[0035] Fig. 6A shows bar graphs of leaching efficiency for the indicated metals after incubation of NMC622 with leaching solutions prepared with the indicated fuel source acidified with H2SO4. Solutions c-M9K-Fe-H2SO4 and C-M9K-SS-H2SO4 are control media prepared with no bacterial inoculation.
[0036] Fig. 6B shows bar graphs of leaching efficiency for the indicated metals after incubation of NMC622 with leaching solutions prepared with the indicated fuel source acidified with HC1.
[0037] Fig. 7A shows XRD traces (intensity versus 29 degrees) of pristine NMC622 cathode powder (black) before the leaching process and post-leaching materials in the indicated leaching systems.
[0038] Fig. 7B shows XRD traces (intensity versus 29 degrees) of pristine NMC622 cathode powder (black) before the leaching process and post-leaching materials in various controlled leaching systems (c is the absence of bacterial inoculation).
[0039] DETAILED DESCRIPTION
[0040] The method for recovering one or more metals from a spent lithium-ion battery (LIB) summarized above features a step of inoculating an iron- oxidizing acidophilic bacteria into a medium that contains a source of magnesium, a source of
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[0042] potassium, a source of phosphate, a source of calcium, a source of iron and, optionally, a source of nitrogen.
[0043] The iron- oxidizing acidophilic bacteria can be a member of the genus Leptospirillum or Acidithiobacillus, preferably Leptospirillum ferriphilum, Leptospirillum ferrooxidans, Leptospirillum rubarum, Leptospirillum ferrodiazotrophum, Acidithiobacillus ferrooxidans, Acidithiobacillus ferrivorans, Acidithiobacillus ferridurans, Acidithiobacillus ferriphilus, or Acidithiobacillus ferrianus, and more preferably Acidithiobacillus ferrooxidans. Mixtures of the above acidophilic bacteria can also be used.
[0044] The source of iron in the medium includes metallic Fe, which can be, but is not limited to, iron powder and stainless-steel powder. In a particular method, the iron powder or stainless-steel powder is obtained from spent LIB material.
[0045] In the medium, the source of nitrogen, if present, can be urea, an amino acid, or ammonia, such as (NH4)2SO4, NH4C1, NH4NO3, (NH4)3PO4, NH4HCO3, and (NH4)2CO3. In some embodiments, the iron- oxidizing acidophilic bacteria can fix nitrogen and, as such, the nitrogen source is optional.
[0046] The source of magnesium can be one or more of MgSO4, MgCh, MgF2, MgBr2, Mgl2, and Mg(NO3)2.
[0047] The source of potassium can be selected from KC1, KF, KBr, KI, K2SO4, KH2PO4, K2HPO4, K3PO4, and KNO3.
[0048] The source of phosphate is selected from NH4H2PO4, (NH4)2HPO4, (NH4)3PO4, LiH2PO4, Li2HPO4, Li3PO4, NaH2PO4, Na2HPO4, Na3PO4, KH2PO4, K2HPO4, and K3PO4,
[0049] Further, the source of calcium can be, but is not limited to, Ca(NO3)2, CaCl2, CaBr2, Cal2, CaSO4, and Ca3(PO4)2
[0050] In the above method, the step of inoculating the iron-oxidizing acidophilic bacteria into the medium forms the inoculant. The method includes a step of acidifying the inoculant to a pH lower than 4, preferably lower than 3, and more preferably 1 to 2 (e.g., 1 to 1.5, 1.5 to 2, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, and 2). The acidification step is accomplished by adding an acid that can be, but is not limited to, H2SO4, HC1, HF, HBr, HI, HNO3, H3BO3, HC1O4, and H3PO4.
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[0052] The method also includes a culturing step in which the acidified inoculant described in the preceding paragraph is cultured to form a leaching solution in which the metallic Fe is oxidized to Fe3+. The culturing step is carried out until the concentration of Fe3+reaches at least 1 g / L, preferably at least 2 g / L, and more preferably 3 g / L to 6 g / L (e.g., at least 1.5 g / L, 3 g / L to 4 g / L, 5 g / L to 6 g / L, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, and 6 g / L).
[0053] Additionally, in a mixing step, a spent lithium-ion battery (LIB) material containing one or more metals is mixed with the leaching solution. The metals can be, e.g., one or more of Li, Mn, Ni, Co, Al, Cu, Zn, Pb, Cd, Ag, Fe, and Hg.
[0054] The mixture is then incubated until the metal(s) are solubilized, forming a pregnant leaching mixture. The solubilized metals are then recovered from the pregnant leaching mixture. Upon carrying out the method, the percent recovery of the one or more metals is from 65% to 99%, preferably above 75%, and more preferably above 80% (75% to 99%, above 80%, above 90%, above 95%, 80%, 85%, 90%, 95%, and 99%), as compared to the percent recovery achieved by dissolving the spent LIB material in aqua regia.
[0055] Also disclosed is a composition for recovering metals from a spent LIB.
[0056] The composition includes an iron-oxidizing acidophilic bacterium and a medium that contains a source of magnesium, a source of potassium, a source of phosphate, a source of calcium, a source of iron, and, optionally, a source of nitrogen.
[0057] The iron- oxidizing acidophilic bacteria is a member of the genus as described above. Also described above are the source of nitrogen, the source of magnesium, the source of potassium, the source of phosphate; and the source of calcium.
[0058] The source of iron in the composition includes metallic Fe and the source of iron can be, e.g., iron powder or stainless-steel powder.
[0059] The pH of the composition is 1 to 3 (e.g., 1 to 2, 2 to 3, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, and 3).
[0060] Further, the composition has an Fe3+concentration of at least 1 g / L, preferably at least 2 g / L, and more preferably 3 g / L to 6 g / L (e.g., at least 1.5 g / L, 3 g / L to 4 g / L, 5 g / L to 6 g / L, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, and 6 g / L).
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[0062] A method is provided for recycling a spent LIB by grinding the spent LIB into a powder, mixing it with the above composition, and recovering metals from the spent LIB.
[0063] Also within the scope of the invention is a method of culturing an ironoxidizing acidophilic bacterium.
[0064] The method includes forming an inoculant by inoculating the iron- oxidizing acidophilic bacterium into a medium that includes a source of magnesium, a source of potassium, a source of phosphate, a source of calcium, a source of iron, and, optionally, a source of nitrogen. The iron-oxidizing acidophilic bacterium and the sources of nitrogen, magnesium, potassium, phosphate, calcium, and iron are those discussed above.
[0065] Another step in the method is acidifying the inoculant to a pH lower than 4, preferably lower than 3, and more preferably 1 to 2 (e.g., 1 to 1.5, 1.5 to 2, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, and 2). The acidification step is accomplished by adding an acid that can be, but is not limited to, H2SO4, HC1, HF, HBr, HI, HNO3, H3BO3, HCIO4, and H3PO4.
[0066] The acidified inoculant is incubated at 20°C to 35°C (e.g., 20°C to 30°C, 25°C to 35°C, 20°C 22.5°C 25°C 27.5°C 30°C 32.5°C, and 35°C), preferably at 30°C.
[0067] Finally, disclosed is a method for producing a composition for recovering metals from a spent LIB that includes, among others, a step of inoculating an ironoxidizing acidophilic bacteria into a medium that contains a source of magnesium, a source of potassium, a source of phosphate, a source of calcium, a source of iron, and, optionally, a source of nitrogen, to form an inoculant, the source of iron including metallic Fe, e.g., iron powder and stainless-steel powder. In a particular method, the iron powder or stainless-steel powder is obtained from the spent LIB.
[0068] The iron- oxidizing acidophilic bacterium and the sources of nitrogen, magnesium, potassium, phosphate, calcium, and iron are those discussed above.
[0069] The method for producing a composition for recovering metals from a spent LIB also includes a step of acidifying the inoculant to a pH lower than 4, preferably lower than 3, and more preferably 1 to 2 (e.g., 1 to 1.5, 1.5 to 2, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, and 2).
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[0071] The final step is culturing the acidified inoculant to form a leaching solution, whereby the metallic Fe is oxidized to Fe3+, thus producing a composition in which the concentration of Fe3+is at least 1 g / L, preferably at least 2 g / L, and more preferably 3 g / L to 6 g / L (e.g., at least 1.5 g / L, 3 g / L to 4 g / L, 5 g / L to 6 g / L, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, and 6 g / L). The culturing step is carried out at 20°C to 35°C (e.g., 20°C to 30°C, 25°C to 35°C, 20°C 22.5°C 25°C 27.5°C 30°C 32.5°C, and 35°C), preferably at 30°C.
[0072] The invention includes the following aspects:
[0073] Aspect 1. A method for recovering one or more metals from a spent lithium- ion battery (LIB), the method comprising: inoculating an iron- oxidizing acidophilic bacteria into a medium that contains a source of magnesium, a source of potassium, a source of phosphate, a source of calcium, a source of iron, and, optionally, a source of nitrogen, to form an inoculant, the source of iron including metallic Fe; acidifying the inoculant to a pH lower than 4, preferably lower than 3, and more preferably 1 to 2; culturing the acidified inoculant to form a leaching solution, whereby the metallic Fe is oxidized to Fe3+; mixing a spent LIB material with the leaching solution to form a mixture, the spent LIB material containing one or more metals; incubating the mixture until the one or more metals are solubilized to obtain a pregnant leaching mixture; and recovering the one or more metals from the pregnant leaching mixture.
[0074] Aspect 2. The method of aspect 1, wherein the iron- oxidizing acidophilic bacteria is a member of the genus Leptospirillum or Acidithiobacillus, preferably Leptospirillum ferriphilum, Leptospirillum ferrooxidans, Leptospirillum rubarum, Leptospirillum ferrodiazotrophum, Acidithiobacillus ferrooxidans, Acidithiobacillus ferrivorans, Acidithiobacillus ferridurans, Acidithiobacillus ferriphilus, or Acidithiobacillus ferrianus, and more preferably Acidithiobacillus ferrooxidans.
[0075] Aspect 3. The method of aspect 1 or 2, wherein the one or more metals are selected from Li, Mn, Ni, Co, Al, Cu, Zn, Pb, Cd, Ag, Fe, and Hg.
[0076] Aspect 4. The method of aspect 3, wherein a percent recovery of the one or more metals is from 65% to 99%, preferably above 75%, and more preferably above 80%, as compared to the percent recovery achieved by dissolving the spent LIB material in aqua regia.
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[0078] Aspect 5. The method of any one of the preceding aspects, wherein the acidification step is accomplished by adding H2SO4, HC1, HF, HBr, HI, HNO3, H3BO3, HCIO4, or H3PO4.
[0079] Aspect 6. The method of any one of the preceding aspects, wherein the source of nitrogen is urea, an amino acid, or ammonia, such as (NH4)2SO4, NH4CI, NH4NO3, (NH4)3?O4, NH4HCO3, and (NH4)2CO3, the source of magnesium is MgSC , MgCh, MgF2, MgBr2, Mgl2, or Mg(NC>3)2, the source of potassium is KC1, KF, KBr, KI, K2SO4, KH2PO4, K2HPO4, K3PO4, or KNO3, the source of phosphate is NH4H2PO4, (NH4)2HPO4, (NH4)3PO4, LiH2PO4, Li2HPO4, Li3PO4, NaH2PO4, Na2HPO4, Na3PO4, KH2PO4, K2HPO4, or K3PO4, the source of calcium is Ca(NC>3)2, CaCh, CaBr2, Cah, CaSO4, or Ca3(PC>4)2, and the source of iron is iron powder or stainless- steel powder.
[0080] Aspect 7. The method of any one of the preceding aspects, wherein the iron powder or stainless-steel powder is obtained from the spent LIB.
[0081] Aspect 8. The method of any one of the preceding aspects, wherein the culturing step is carried out until a concentration of Fe3+reaches at least 1 g / L, preferably at least 2 g / L, and more preferably 3 g / L to 6 g / L.
[0082] Aspect 9. A composition for recovering metals from a spent LIB, the composition comprising an iron-oxidizing acidophilic bacterium and a medium that contains a source of magnesium, a source of potassium, a source of phosphate, a source of calcium, a source of iron, and, optionally a source of nitrogen, wherein the source of iron includes metallic Fe, and a pH of the composition is 1 to 3.
[0083] Aspect 10. The composition of aspect 9, wherein the iron- oxidizing acidophilic bacteria is a member of the genus Leptospirillum or Acidithiobacillus, preferably Leptospirillum ferriphilum, Leptospirillum ferrooxidans, Leptospirillum rubarum, Leptospirillum ferrodiazotrophum, Acidithiobacillus ferrooxidans, Acidithiobacillus ferrivorans, Acidithiobacillus ferridurans, Acidithiobacillus ferriphilus, and Acidithiobacillus ferrianus, and more preferably Acidithiobacillus ferrooxidans.
[0084] Aspect 11. The composition of aspect 9 or 10, wherein the source of nitrogen is urea, an amino acid, or ammonia, such as (NH4)2SO4, NH4CI, NH4NO3, (NH4)3?O4, NH4HCO3, and (NH4)2CO3, the source of magnesium is MgSCL, MgCh, MgF2,
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[0086] MgBi2, Mgl2, or Mg(NOs)2, the source of potassium is KC1, KF, KBr, KI, K2SO4, KH2PO4, K2HPO4, K3PO4, or KNO3, the source of phosphate is NH4H2PO4, (NH4)2HPO4, (NH4)3PO4, LiH2PO4, Li2HPO4, Li3PO4, NaH2PO4, Na2HPO4, Na3PO4, KH2PO4, K2HPO4, or K3PO4, the source of calcium is Ca(NC>3)2, CaCh, CaBr2, Cah, CaSO4, or Ca3(PC>4)2, and the source of iron is iron powder or stainless- steel powder.
[0087] Aspect 12. The composition of any one of aspects 9 to 11, wherein a concentration of Fe3+in the composition is at least 1 g / L, preferably at least 2 g / L, and more preferably 3 g / L to 6 g / L.
[0088] Aspect 13. A method of culturing an iron-oxidizing acidophilic bacterium, the method comprising inoculating the iron-oxidizing acidophilic bacterium into a medium that includes a source of magnesium, a source of potassium, a source of phosphate, a source of calcium, a source of iron, and, optionally, a source of nitrogen; acidifying the inoculant to a pH lower than 4, preferably lower than 3, and more preferably 1 to 2; and incubating the acidified inoculant, wherein the source of iron contains metallic Fe.
[0089] Aspect 14. The method of aspect 13, wherein the iron-oxidizing acidophilic bacteria is a member of the genus Leptospirillum or Acidithiobacillus, preferably Leptospirillum ferriphilum, Leptospirillum ferrooxidans, Leptospirillum rubarum, Leptospirillum ferrodiazotrophum, Acidithiobacillus ferrooxidans, Acidithiobacillus ferrivorans, Acidithiobacillus ferridurans, Acidithiobacillus ferriphilus, and Acidithiobacillus ferrianus, and more preferably Acidithiobacillus ferrooxidans.
[0090] Aspect 15. The method of aspect 13 or 14, wherein the source of nitrogen is urea, an amino acid, or ammonia, such as (NH4)2SO4, NH4CI, NH4NO3, (NH4)3?O4, NH4HCO3, and (NH4)2CO3, the source of magnesium is MgSCL, MgCh, MgF2, MgBr2, Mgl2, or Mg(NC>3)2, the source of potassium is KC1, KF, KBr, KI, K2SO4, KH2PO4, K2HPO4, K3PO4, or KNO3, the source of phosphate is NH4H2PO4, (NH4)2HPO4, (NH4)3PO4, LiH2PO4, Li2HPO4, Li3PO4, NaH2PO4, Na2HPO4, Na3PO4, KH2PO4, K2HPO4, or K3PO4, the source of calcium is Ca(NC>3)2, CaCh, CaBr2, Cah, CaSO4, or Ca3(PC>4)2, and the source of iron is iron powder or stainless- steel powder.
[0091] Aspect 16. The method of any one of aspects 13 to 15, wherein the iron powder or stainless- steel powder is obtained from a spent LIB.
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[0093] Aspect 17. The method of any one of aspects 13 to 16, wherein the incubating step is carried out at 20°C to 35°C, preferably at 30°C.
[0094] Aspect 18. The method of any one of aspects 13 to 17, wherein the acidification step is accomplished by adding H2SO4, HC1, HF, HBr, HI, HNO3, H3BO3, HCIO4, or H3PO4.
[0095] Aspect 19. A method for producing a composition for recovering metals from a spent lithium-ion battery (LIB), the method comprising: inoculating an ironoxidizing acidophilic bacteria into a medium that contains a source of magnesium, a source of potassium, a source of phosphate, a source of calcium, a source of iron, and, optionally, a source of nitrogen, to form an inoculant, the source of iron including metallic Fe; acidifying the inoculant to a pH lower than 4, preferably lower than 3, and more preferably 1 to 2; and culturing the acidified inoculant to form a leaching solution, whereby the metallic Fe is oxidized to Fe3+and a concentration of Fe3+in the composition is at least 1 g / L, e.g., at least 2 g / L and 3 g / L to 6 g / L.
[0096] Aspect 20. The method of aspect 19, wherein the source of nitrogen is urea, an amino acid, or ammonia, such as (NH4)2SO4, NH4CI, NH4NO3, (NH4)3?O4, NH4HCO3, and (NH4)2CO3, the source of magnesium is MgSCL, MgCh, MgF2, MgBr2, Mgl2, or Mg(NC>3)2, the source of potassium is KC1, KF, KBr, KI, K2SO4, KH2PO4, K2HPO4, K3PO4, or KNO3, the source of phosphate is NH4H2PO4, (NH4)2HPO4, (NH4)3PO4, LiH2PO4, Li2HPO4, Li3PO4, NaH2PO4, Na2HPO4, Na3PO4, KH2PO4, K2HPO4, or K3PO4, the source of calcium is Ca(NC>3)2, CaCh, CaBr2, Cah, CaSO4, or Ca^fPCUk, and the source of iron is iron powder or stainless- steel powder.
[0097] Aspect 21. The method of aspect 20, wherein the iron powder or stainless-steel powder is obtained from the spent LIB.
[0098] Aspect 22. The method of any one of aspects 19 to 21, wherein the culturing step is carried out at 20°C to 35°C, preferably at 30°C.
[0099] Aspect 23. A method for recycling a spent LIB, the method comprising grinding the spent LIB into a powder, mixing it with the composition of any one of aspects 9 to 12, and recovering metals from the spent LIB.
[0100] The invention further includes the following aspects:
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[0102] Aspect i. A composition for recovering metals from a spent LIB, the composition comprising an iron- oxidizing acidophilic bacterium and a medium that contains a source of magnesium, a source of potassium, a source of phosphate, a source of calcium, a source of iron, and, optionally, a source of nitrogen, wherein the source of iron includes metallic Fe, and a pH of the composition is 1 to 3.
[0103] Aspect ii. A method of culturing an iron- oxidizing acidophilic bacterium, the method comprising inoculating the iron-oxidizing acidophilic bacterium into a medium that includes a source of magnesium, a source of potassium, a source of phosphate, a source of calcium, a source of iron, and, optionally, a source of nitrogen; acidifying the inoculant to a pH lower than 4 (e.g., preferably lower than 3 and more preferably 1 to 2); and incubating the acidified inoculant, wherein the source of iron contains metallic Fe.
[0104] Aspect iii. A method for producing a composition for recovering metals from a spent lithium-ion battery (LIB), the method comprising: inoculating an ironoxidizing acidophilic bacteria into a medium that contains a source of magnesium, a source of potassium, a source of phosphate, a source of calcium, a source of iron, and, optionally, a source of nitrogen, to form an inoculant, the source of iron including metallic Fe; acidifying the inoculant to a pH lower than 4 (e.g., preferably lower than 3 and more preferably 1 to 2); and culturing the acidified inoculant to form a leaching solution, whereby the metallic Fe is oxidized to Fe3+and a concentration of Fe3+in the composition is at least 1 g / L (e.g., preferably at least 2 g / L and more preferably 3 g / L to 6 g / L.
[0105] Aspect iv. A method for recovering one or more metals from a spent lithium-ion battery (LIB), the method comprising: inoculating an iron-oxidizing acidophilic bacteria into a medium that contains a source of magnesium, a source of potassium, a source of phosphate, a source of calcium, a source of iron, and, optionally, a source of nitrogen, to form an inoculant, the source of iron including metallic Fe; acidifying the inoculant to a pH lower than 4, preferably lower than 3, and more preferably 1 to 2; culturing the acidified inoculant to form a leaching solution, whereby the metallic Fe is oxidized to Fe3+; mixing a spent LIB material with the leaching solution to form a mixture, the spent LIB material containing one or more metals; incubating the mixture
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[0107] until the one or more metals are solubilized to obtain a pregnant leaching mixture; and recovering the one or more metals from the pregnant leaching mixture.
[0108] Aspect v. The composition of aspect i or the method of any one of aspects ii- iv, wherein wherein the iron-oxidizing acidophilic bacteria is a member of the genus Leptospirillum or Acidithiobacillus, preferably Leptospirillum ferriphilum, Leptospirillum ferrooxidans, Leptospirillum rubarum, Leptospirillum ferrodiazotrophum, Acidithiobacillus ferrooxidans, Acidithiobacillus ferrivorans, Acidithiobacillus ferridurans, Acidithiobacillus ferriphilus, or Acidithiobacillus ferrianus, and more preferably Acidithiobacillus ferrooxidans.
[0109] Aspect vi. The composition of aspect i or v or the method of any one of aspects ii-v, wherein the source of nitrogen is urea, an amino acid, or ammonia, such as (NH4)2SO4, NH4C1, NH4NO3, (NH4)3PO4, NH4HCO3, and (NH4)2CO3, the source of magnesium is MgSO4, MgCl2, MgF2, MgBr2, Mgl2, or Mg(NO3)2, the source of potassium is KC1, KF, KBr, KI, K2SO4, KH2PO4, K2HPO4, K3PO4, or KNO3, the source of phosphate is NH4H2PO4, (NH4)2HPO4, (NH4)3PO4, LiH2PO4, Li2HPO4, Li3PO4, NaH2PO4, Na2HPO4, Na3PO4, KH2PO4, K2HPO4, or K3PO4, the source of calcium is Ca(NO3)2, CaCl2, CaBr2, Cal2, CaSO4, or Ca3(PO4)2, and the source of iron is iron powder or stainless- steel powder.
[0110] Aspect vii. The method of aspect vi, wherein the iron powder or stainless- steel powder is obtained from the spent LIB.
[0111] Aspect viii. The method of any one of aspects ii-vii, wherein the acidification step is accomplished by adding H2SO4, HC1, HF, HBr, HI, HNO3, H3BO3, HC1O4, or H3PO4.
[0112] Aspect ix. The method of any one of aspects iii-viii, wherein the culturing step is carried out until a concentration of Fe3+reaches at least 1 g / L, preferably at least 2 g / L, and more preferably from 3 g / L to 6 g / L.
[0113] Aspect x. The method of any one of aspects iv-ix, wherein the one or more metals are selected from the group consisting of Li, Mn, Ni, Co, Al, Cu, Zn, Pb, Cd, Ag, Fe, and Hg.
[0114] Aspect xi. The method of aspects iv-x, wherein a percent recovery of the one or more metals is from 65% to 99%, preferably above 75%, and more preferably
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[0116] above 80%, as compared to the percent recovery achieved by dissolving the spent LIB material in aqua regia.
[0117] Aspect xii. The method of any one of aspects ii-xi, wherein the incubating step is carried out at 20°C to 35°C, preferably at 30°C.
[0118] Aspect xiii. A method for recycling a spent LIB, the method comprising grinding the spent LIB into a powder, mixing it with the composition of any one of aspects 1, 5, and 6, and recovering one or more metals from the spent LIB.
[0119] Aspect xiv. The composition of any one of aspects i, v, and vi or the method of aspect 13, wherein a concentration of Fe3+in the composition is at least 1 g / L, preferably at least 2 g / L, and more preferably 3 g / L to 6 g / L.
[0120] Aspect xv. The method of aspect xiii or xiv, wherein the one or more metals recovered from the spent LIB are selected from the group consisting of Li, Mn, Ni, Co, Al, Cu, Zn, Pb, Cd, Ag, Fe, and Hg.
[0121] Without further elaboration, it is believed that one skilled in the art can, based on the disclosure herein, utilize the present invention to its fullest extent. The following specific examples are, therefore, to be construed as merely descriptive, and not limitative of the remainder of the disclosure in any way whatsoever. All publications and patent documents cited herein are incorporated by reference in their entirety.
[0122] EXAMPLES
[0123] Example 1: Cultivation of Microorganism
[0124] Acidithiobacillus ferrooxidans strain F221 was acquired from DSMZ Germany (DSM 1927). The bacteria was grown in three different media to determine the effect of the microbial fuel source on bacterial growth and leaching efficiency of LIB cathode materials. See Table 1 below. The traditional Modified 9K (M9K) medium was composed of (NFL SCh (3.0 g / L) (Millipore Sigma), KC1 (0.1 g / L) (Fisher Scientific), K2HPO4 ••3H2O (0.5 g / L) (Fisher Scientific), MgSCh •-7H2O (0.5 g / L) (Fisher Scientific), Ca(NOs)2 (0.01 g / L) (Fisher Scientific), and FeSCh-* 7H2O (44.22 g / L) was labeled as M9K-FS. M9K-FS was used as the parent culture for inoculations as detailed below once it reached the stationary phase.
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[0126] Table 1. Media components
[0127] Media Component Compound Qty. (g / L)
[0128] Nitrogen source (NH4)2SO43.0
[0129] Magnesium ion source MgSO4• 7H2O 0.5
[0130] Potassium source KC1 0.1
[0131] Phosphate source and buffer K2HPO4 0.5
[0132] Calcium source Ca(NO3)2• 4H2O 0.01
[0133] Energy source (M9K-FS) FeSO4• 7H2O 44.22
[0134] Energy source (M9K-Fe) Fe powder 3-5
[0135]
[0136] Energy source (M9K-SS) SS powder 4-7
[0137] The media for the M9K-Fe culture was prepared using the identical amount of minerals as noted above in Table 1 for the M9K-FS medium, with the energy source being pure iron (Fe) powder (Thermo Fisher® >99% (metals basis), 200 mesh) instead of FeSCh. The small particle size of the metallic Fe allows for a larger surface area to volume ratio enabling optimal contact with the bacteria. The pH of the culture was then adjusted to 1.6- 1.7 using either 2M H2SO4 (Millipore Sigma®) or 2M HC1 (Fisher Scientific®) and labeled as M9K-Fe-H2SO4 or M9K-Fe-HCl, respectively.
[0138] The third culture solution followed the same procedure as described above, with the energy source being stainless steel (SS) powder (Thermo Fisher®; 325 mesh). This material was chosen as a representation of the protective casings found in electric vehicle batteries and other industrial waste materials, which aligns with the goal of decreasing dependence on externally supplied chemical fuels. The SS powder has an average composition of Fe:Cr:Ni:Mo of 67.5:17:11:2.5 wt%. The difference in the amount of Fe and SS powder used was to ensure a similar supply of Fe. The resulting medium was labeled as M9K-SS-H2SO4 or M9K-SS-HC1 depending on the acid used for the initial pH adjustment. Afterwards, each culture medium was inoculated with 20% v / v parent culture, and the resulting cultures were then incubated at 30 °C while continuously shaking at 170 rpm.
[0139] Example 2: Model battery cathode material synthesis
[0140] LifNio.6Mno.2Coo.2jO2 LIB cathode precursors were synthesized adopting a modified solid-state method. Briefly, a total of 2 g mixture of NiO (99% metals basis,
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[0142] Sigma Aldrich), MnO (99% metals basis, Sigma Aldrich), and CO3O4 powders (99.7% metals basis, Alfa Aesar) (6:2:2) were sealed with Z1O2 (MSE) balls in a 50 mL Teflon planetary ball mill (MSE®) and milled using a high energy ball mill (SPEX Model 8000-D, Spex CertiPrep™, Metuchen, NJ) for 1 h. The formed precursor powder was collected and ground in a mortar and pestle for 10 min with 3 mol% excess Li2COs (99%; Thermo Fisher®), according to the Li:Ni:Mn:Co ratio in the formula LifNio.6Mno.2Coo.2JO2. The resulting powder was then pressed into pellets to ensure optimal atomic contact. The pellets were loaded into a quartz crucible and heated in a tube furnace for 5 h at 450 °C under ambient pressure with compressed air flow of 8 standard cubic centimeter per minute (SCCM). The furnace was then heated to 800°C (ramping rate: 5 °C / min) and maintained at this temperature for 10 h under O2 flow (8 SCCM). The samples were allowed to cool to room temperature under continued O2 flow at the same rate. The sintered pellets were ground using a mortar and pestle then passed through a 38-pm mesh sieve (Advantech®). The preparation of electrode materials was completed by milling the synthesized NMC622 powder with carbon black (Fuel Cell Store) and poly(vinylidene) fluoride (PVDF) (Sigma Aldrich®) in a 92:4:4 weight ratio.
[0143] To compare the home-synthesized cathode materials with literature reports, the NMC622 powder was characterized by the Brunauer-Emmett-Teller (BET) method using an ASAP 2020 plus physisorption analyzer for quantification of its specific surface areas. The crystallinity was studied using a powder X-ray diffractometer (XRD; Bruker D8 Advance with a Cu Ka X-ray). The microstructures were examined using a scanning electron microscope (SEM; JEOL JSM-7001F) equipped with energy dispersive X-ray spectroscopy (EDS) mapping capabilities using an Oxford AZtec probe. Elemental analysis was also performed on the model cathode material using inductively coupled plasma optical emissions spectrometer (ICP-OES; Agilent 5110). For this study, 3 mL of aqua regia (HC1 (35%):HNOs (68%)=3: 1) was mixed with 0.3 g model cathode materials to simulate a 10 g / L leaching process similar to the bioleaching measurements described, infra. The reaction took place in an autoclave at 90°C for 12 h. The reaction mixture was filtered using a PVDF membrane filter with polypropylene housing and a pore size of 0.22 / zm and diluted 100 times for
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[0145] Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) measurements.
[0146] Example 3: Bioleaching Studies
[0147] Once cultures reached their stationary phase, the bioleaching experiments were conducted by adding model cathode materials (pulp density of 10 g / L in the resulting solution) to bacterial cultures M9K-FS, M9K-Fe-H2SO4, M9K-Fe-HCl, M9K-SS-H2SO4, and M9K-SS-HC1, respectively. This results in a two-step process (allowing stationary phase to be reached first before adding cathode material) that takes place in one pot (bacteria remain in the leaching solution with the cathode material). In addition, control experiments were carried out in the culture media without bacteria. For all the leaching experiments, the processes were conducted at 30°C with continuous shaking at 170 rpm. After 48 h, any remaining residues were removed from the bioleaching liquor. The quantities of each dissolved metal in the leaching liquor (Ei, Ni, Mn, and Co) were analyzed using ICP-OES. The leaching efficiency of the metals was determined by comparing the samples with aqua regia digestion of the same model cathode materials (see eq 1 below), which was achieved by adding a 10 g / E ratio of model cathode material (NMC622) to aqua regia and autoclaving at 90°C for 12 h. Such a method of determining leaching efficiency avoids underestimation due to insoluble components in cathode materials.
[0148] Leaching Efficiency (%) = MbioHM / MarTOO (eq 1)
[0149] MbioHM = metal concentration in bioleaching solution,
[0150] Mar= metal concentration in aqua regia solution
[0151] Example 4: Analytical Methods
[0152] [Fe2+] was quantified by measuring absorption using a microplate reader (BioTek Epoch 2™). A 3% 1,10-phenanthroline (Sigma Aldrich®) solution was first made as the indicator for spectrometer readout. For quantifications of Fe2+, 20 pL of a given culture was collected and diluted with 230 pL of deionized (DI) water (resistance: 18.2 MQ). Then, 50 pL of the resulting dilution was introduced to 8 pL of the indicator solution and left to sit for 2 min before a final dilution of 42 pL DI water
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[0154] was added. The spectrophotometric optical absorption was measured at a wavelength of 1 = 508 nm.
[0155] [Fe3+] was quantified using the same spectrophotometer as noted above. A 10% 5-sulfosalicylic acid (SSA) (Lab ally) solution was used as an indicator. 2 pL of a given culture was collected and diluted with 970 pL of DI water, followed by mixing with 30 pL of SSA. The spectrophotometric optical absorption was measured at a wavelength of = 500 nm.
[0156] The biogenic acid concentration was quantified using the classical acid-base titration method. For this measurement, the culture solution was first diluted 10 times and centrifuged at 12,000 rpm for 10 min to remove precipitates. The solution was then titrated with a 0.1 M NaOH solution using bromothymol blue as the indicator. Example 5: Aft shows metabolic activity in the modified media
[0157] The fundamental metabolic processes that support the function and growth of Aft rely on the reaction: Fe2+— Fe3++ e". Electrons generated from this reaction are transferred though the electron transport chain, forming a proton gradient across the membrane for the synthesis of ATP as the primary energy source. Thus, it is common to monitor the concentration changes of two key species, [Fe2+] and [Fe3+], to determine the growth of Atf A third indicator of a healthy Aft culture is the pH.
[0158] Highly acid environments are necessary to maintain an internal pH of 6.5 for these extremophiles to remain active. Conversely, the metabolism of At / helps maintain the pH of its culture low, with 1.5-2.0 being an optimum range. Changes of these three key indicators, [Fe2+], [Fe3+], and pH, throughout the cultivation process in the modified M9K media are summarized in Figs 2A-2D. Similar trends were observed in all samples. The pH of the cultures remained relatively constant (1.50-1.75) throughout the growth process with a slight variation depending on the day. The Fe2+concentration generally decreased over the course of cell growth, and the Fe3+concentration generally increased. For instance, the initial [Fe3+] was approximately 1 g / L and increased to 2.5 g / L and 3.6 g / L in M9K-Fe-H2SO4 (see Fig. 2A) and M9K-SS-H2SO4 (see Fig. 2B), respectively once the stationary phase was reached (Day 20). Correspondingly, the [Fe2+] was ~4.5 g / L on Day 0, and decreased to 3.0 g / L on Day 20 for M9K-Fe-H2SO4 and 2.8 g / L on Day 20 for M9K-SS-H2SO4. See Figs. 2A and
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[0160] 2B. The changes were similar for M9K-Fe-HCl and M9K-SS-HC1, with [Fe3+] increasing from approximately 0.5 g / L on Day 0 to 2.6 g / L and 3.1 g / L, respectively, on Day 20, and [Fe2+] decreasing from ~4.5 g / L on Day 0 to 3.4 g / L and 2.7 g / L respectively on Day 20. See Figs. 2C and 2D. The steady increase of Fe3+concentration, as well as the decrease of [Fe2+], is an important indication of cell activity, as mentioned above and seen in equation 2 below.
[0161] 2Fe2++ i / zCh + 2H+— ► 2Fe3++ H2O (eq 2) The corroboration between Fe3+concentration change and cell activity was further confirmed by the observation of minimal [Fe3+] change in the control media (c-M9K-Fe, and C-M9K-SS), which contained the same nutrients, Fe or SS, the acid for the adjustment of initial pH, but without the addition of bacteria. See Figs 3A-3B.
[0162] The traditional culture medium, i.e., M9K-FS, was produced and monitored to serve as the baseline for comparisons of the modified growth trends. Due to the large quantity of FeSCU used (44.22 g / L), the initial [Fe3+] (-2.5 g / L on Day 0) and that in the stationary phase (-10.6 g / L by Day 16) were noticeably higher than those observed for c-M9K-Fe, and C-M9K-SS. Compare Fig. 3 (M9K-FS)with Figs. 2A-2D. This conspicuous difference notwithstanding, the pH values of all cultures were comparable and remained relatively constant throughout the growth process. The results suggest that the high initial | FeSCUI in traditional biohydrometallurgy was not necessary to maintain a desirable pH for leaching purposes. It is noteworthy that the observed trends in cell growth were consistent with HC1 or H2SO4 used as the acid for the adjustment of the initial pH, implying that cell growth does not depend on the availability of excess SO42’. This observation is contradictory to a previous report that the acidity of the solution is maintained by the oxidation of sulfur compounds within the system.
[0163] As acidolysis is a key factor for high leaching efficiencies of desired metals, the acid concentration of the culture was taken by acid-base titration before and after the stationary phase was reached. The initial acid concentration of the traditional media (M9K-FS) was determined as 0.14 M, and those of the modified cultures of M9K-Fe-H2SO4 and M9K-SS-H2SO4 were 0.088 M and 0.076 M, respectively. After the stationary phase was reached, and prior to the addition of model cathode
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[0165] materials, the acid concentration of M9K-FS was 0.40 M and those of M9K-Fe-H2SO4 and M9K-SS-H2SO4 were 0.35 M and 0.31 M, respectively. These results further corroborate with the pH measurements and support desirable cell growth and acidification of the culture. Interestingly, while the initial acid concentrations in M9K-Fe and M9K-SS in HC1 were relatively low in comparison to those in H2SO4, at 0.018 M and 0.010 M, respectively, they both reached high value of 0.50 M at the stationary phase. This further aids in the claim that culture systems that mitigate sulfate sources are still capable of efficient cell growth and acid production required for the leaching of electrode materials. These results indicate that, when replacing the FeSO4 fuel source with an effective Fe source, the acids utilized for the acidification can be changed. The results are highly reproducible and further support the understanding that excess SO42’ is not critical to the growth of Atf. Lastly, it is noted that the biogenic acid concentration needed for the most efficient battery cathode leaching was reported to be 0.17-0.52 M, which is lower than that by the hydrometallurgy approach (1-4 M). This is because the bacterium continues to produce protons during its metabolism, keeping a continued supply to assist the dissolution of cathode materials.
[0166] Example 6: Synthesized NMC622 is a representative model for cathode material.
[0167] NMC622 was chosen as the prototypical study platform for several reasons. First, it represents state-of-the- art cathode material commonly found on the market. Second, it allows precise control of the transition metal components and enables accurate quantitative comparisons across various leaching processes. Lastly, because of its well- characterized structure and known chemical and physical properties, it serves as a solid foundation for studying various leaching methods. After synthesis as detailed above, the phase composition and morphology of NMC622 were characterized by XRD and SEM / EDS, and the elemental composition was quantified by ICP-OES. The results are shown in Fig. 5 and Table 2 below.
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[0169] Table 2. Normalized elemental composition of NMC622 as analyzed by ICP-OES Composition of NMC Black Mass analyzed by ICP-OES
[0170] Element % weight
[0171] Li 11.10
[0172] Ni 54.78
[0173] Mn 16.17
[0174]
[0175] Co 17.95
[0176] As shown in Fig. 5, the synthesized NMC622 materials exhibited a layered structure similar to commercially available products. The two dominating XRD reflection peaks correspond to the (003) and (104) planes, the ratio of which is indicative of the cation mixing phenomenon often observed in this type of material. Additionally, significant splitting between the (006) and (102) planes, as well as that between (108) and (110) planes, was observed, supporting a well-ordered hexagonal structure. Using the Scherrer’s equation, the crystalline size of NMC622 was determined to be -33.32 nm, which is comparable to commercially available NMC622. It is noted that the adopted synthesis method produced NMC622 materials with limited cation mixing. Such a mixing was often observed in Ni-rich material, due to the similar bonding environments and comparable ionic radii of Ni2+and Li+. This observation is consistent with literature reports that sintering the precursors in O2 limits the cation mixing. This effect is desirable for LIB applications. Overall, the characterization showed successful reproduction of NMC622 cathode materials that are commonly encountered in practical LIBs.
[0177] Example 7: Efficient biohydrometallurgical leaching in the modified medium The leaching of key elements from cathode materials by biogenically produced acids involves the following main reactions:
[0178] Li2O + 2H+2Li++ H2O (eq 3) M4+ / M3+* + Fe2+M2+ (MO) + Fe3+(eq 4)
[0179] MO + 2H+M2++ H2O (eq 5)
[0180] *(M = Ni, Mn, Co)
[0181] Among these elements, Li is directly solubilized by the acid. Ni, Co, and Mn are first reduced and then solubilized by biogenically produced acids. When NMC622
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[0183] cathode materials were first added, a spike in pH on Day 0 & Day 1 (from ca. 1.65 to 2.12 for M9K-FS as a representative example), was observed due to the alkaline nature of the cathode materials, but it was lowered with further leaching time (final pH 2.01 for M9K-FS as a representative value) due to the metabolism of Aft. See Table 3 below. Notably, in the absence of Atf, the pH for c-M9K-Fe-HCl monotonically increased from 1.65 to 3.73 after 48 h of reactions. A similar increase was observed in C-M9K-SS-HC1, and the control experiments with H2SO4, c-M9K-Fe-H2SO4and c-M9K-SS-H2SO4.
[0184] Table 3. Initial and final pH values of leaching solutions after 48h pH of systems used for leaching
[0185] System Initial pH Final pH
[0186] M9K-FSa1.65 2.01
[0187] M9K-Fe-H2SO4a1.56 2.68
[0188] M9K-SS- H2SO4a1.40 2.71
[0189] M9K-Fe-HCla1.84 2.61
[0190] M9K-SS-HCla1.52 2.16
[0191] c-M9K-Fe- H2SO4b1.46 3.18
[0192] C-M9K-SS- H2SO4b1.67 3.48
[0193] c-M9K-Fe-HClb1.65 3.73
[0194]
[0195] c-M9K-SS-HClb1.67 3.63
[0196] “Leaching solutions prepared by culturing Atf
[0197] bControl leaching solutions without Atf
[0198] As a baseline, the leaching efficiencies of the various metals were first quantified for the conventional Atf growth media involving FeSO4as the fuel source (M9KS). As shown in Figs 6A and 6B, leaching efficiencies for M9KS were 90% (Li), 92% (Ni), 81% (Mn), and 75% (Co). Comparable leaching efficiencies were obtained by the self-sufficient leaching media with Fe as the fuel source and H2SO4as the acid for the initial pH adjustment (M9K-Fe- H2SO4), at 99% (Li), 68% (Ni), 63% (Mn), and 64% (Co). See Fig. 6A. Interestingly, generally higher leaching efficiencies were obtained with SS as the energy source (M9K-SS- H2SO4), at 99% (Li), 71% (Ni), 74% (Mn), and 65% (Co). See Fig. 6A. Notably, consistently higher leaching efficiencies were obtained in the growth media with HC1 as the acid for initial pH adjustment. For instance, in M9K-Fe-HCl, leaching efficiencies of 95% (Li), 91% (Ni), 93% (Mn), and 89% (Co) were obtained. See Fig. 6B. Similarly, in
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[0200] M9K-SS-HC1, leaching efficiencies of 94% (Li), 97% (Ni), 96% (Mn), and 98% (Co) were obtained. See Fig. 6B. Once again, consistently higher leaching efficiencies were observed when SS was used as the fuel source. Lastly, leaching cathode materials by control media without Atf was also carried out, which showed significantly lower leaching efficiencies varying between 21% and 43% for H H2SO4-based solutions and <15% for HCl-based ones. See Figs 6A and 6B.
[0201] Example 8: Post leaching characterization of model materials
[0202] The crystal structures of the post-leaching cathode materials and their controls were characterized using XRD. The results are shown in Figs 7A and 7B. The pristine (black) NMC622 cathode material (bottom traces in Figs. 7A and 7B) was compared to the pattern of the residual material that remains in the culture after the allotted leaching time. The second from bottom trace in Fig. 7A shows the cathode material using FeSCL as the energy source in an H2SO4 acidified culture (M9K-FS). The residual powder has significantly diminished key peaks (003) and (104), and the other characteristic peaks are suppressed and broadened (See Fig. 7A). The disappearance of the XRD peaks is caused by the loss of material within the crystal structure of planes. The peak broadening and slight shift of peak position are believed to be associated with the dissolution of metals from the crystal structure leading to phase impurity and increased D spacing respectively.
[0203] The M9K-Fe-H2SO4, M9K-SS-H2SO4, M9K-Fe-HCl, and M9K-SS-HC1 leaching systems all showed similar XRD patterns with decreased peak intensities. See Fig. 7A. The post-leaching cathode material in M9K-Fe-H2SO4 leaching system showed the lowest decrease in peaks, which is consistent with its lower recovered metals percentage. A similar trend was observed in the M9K-Fe-HCl leaching system which suggests that the metal recoveries using Fe are lower than their SS counterparts.
[0204] Post leaching cathode materials in the control systems (in the absence of bacteria), c-M9K-Fe and C-M9K-SS in HC1, preserved most prominent XRD peaks with small differences compared with pristine material. See Fig. 7B. For example, the peak positions of (003) and (104) showed a slight shift, as the leaching of a small amount of metals widens the d-spacing of the metal oxide lattice. The other control
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[0206] systems, c-M9K-Fe and C-M9K-SS in H2SO4, showed similar trend with that in HC1 systems. See Fig. 7B
[0207] In summary, A. ferrooxidans (Atf) was cultured by replacing a key fuel source, FeSO4, with Fe, to take advantage of the fact that Fe is abundant, cheap, and easy to handle. The one-pot cultures using Fe (or stainless steel) acidified by H2SO4 enabled successful bacterial growth. Furthermore, the results showed that H2SO4 could be replaced by HC1. The HCl-substituted culture solution exhibited even better cell growth without affecting the biological functions, implying that SO42’ does not provide a critical biological function in the metabolism of Atf. The recovery of metals in NMC622 LIB cathode materials was carried out using the modified culture solutions. In a 48 h leaching timeframe, high leaching efficiencies of 94% (Li), 97% (Ni), 96% (Mn), and 98% (Co) were obtained using solutions with stainless steel as the energy source and HC1 as the initial acidification medium. The demonstrated self-sufficient recovery of cathode materials is expected to be impactful in the future of LIB recycling by reducing the need for supplementing the culture and simplifying the conditions for bacterial growth.
[0208] OTHER EMBODIMENTS
[0209] All of the features disclosed in this specification may be combined in any combination. Each feature disclosed in this specification may be replaced by an alternative feature serving the same, equivalent, or similar purpose. Thus, unless expressly stated otherwise, each feature disclosed is only an example of a generic series of equivalent or similar features.
[0210] From the above description, one skilled in the art can easily ascertain the essential characteristics of the present invention, and without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions. Thus, other embodiments are also within the scope of the following claims.
[0211] 4919-4877-2747, v. 1
Claims
Docket No. BCOT-OIO-WOI BC2025.014.wan -25-CLAIMS1. A composition for recovering metals from a spent LIB, the composition comprising an iron- oxidizing acidophilic bacterium and a medium that contains a source of magnesium, a source of potassium, a source of phosphate, a source of calcium, a source of iron, and, optionally, a source of nitrogen, wherein the source of iron includes metallic Fe, and a pH of the composition is 1 to 3.
2. A method of culturing an iron-oxidizing acidophilic bacterium, the method comprising inoculating the iron-oxidizing acidophilic bacterium into a medium that includes a source of magnesium, a source of potassium, a source of phosphate, a source of calcium, a source of iron, and, optionally, a source of nitrogen;acidifying the inoculant to a pH lower than 4, preferably lower than 3, and more preferably 1 to 2; andincubating the acidified inoculant,wherein the source of iron contains metallic Fe.
3. A method for producing a composition for recovering metals from a spent lithium-ion battery (LIB), the method comprising:inoculating an iron- oxidizing acidophilic bacteria into a medium that contains a source of magnesium, a source of potassium, a source of phosphate, a source of calcium, a source of iron, and, optionally, a source of nitrogen, to form an inoculant, the source of iron including metallic Fe;acidifying the inoculant to a pH lower than 4, preferably lower than 3, and more preferably 1 to 2; andculturing the acidified inoculant to form a leaching solution, whereby the metallic Fe is oxidized to Fe3+and a concentration of Fe3+in the composition is at least 1 g / L, preferably at least 2 g / L, and more preferably 3 g / L to 6 g / L.
4. A method for recovering one or more metals from a spent lithium-ion battery (LIB), the method comprising:4919-4877-2747, v. 1Docket No. BCOT-OIO-WOI BC2025.014.wan -26-inoculating an iron- oxidizing acidophilic bacteria into a medium that contains a source of magnesium, a source of potassium, a source of phosphate, a source of calcium, a source of iron, and, optionally, a source of nitrogen, to form an inoculant, the source of iron including metallic Fe;acidifying the inoculant to a pH lower than 4, preferably lower than 3, and more preferably 1 to 2;culturing the acidified inoculant to form a leaching solution, whereby the metallic Fe is oxidized to Fe3+;mixing a spent LIB material with the leaching solution to form a mixture, the spent LIB material containing one or more metals;incubating the mixture until the one or more metals are solubilized to obtain a pregnant leaching mixture; andrecovering the one or more metals from the pregnant leaching mixture.
5. The composition of claim 1 or the method of any one of claims 2-4, wherein wherein the iron- oxidizing acidophilic bacteria is a member of the genus Leptospirillum or Acidithiobacillus, preferably Leptospirillum ferriphilum, Leptospirillum ferrooxidans, Leptospirillum rubarum, Leptospirillum ferrodiazotrophum, Acidithiobacillus ferrooxidans, Acidithiobacillus ferrivorans, Acidithiobacillus ferridurans, Acidithiobacillus ferriphilus, or Acidithiobacillus ferrianus, and more preferably Acidithiobacillus ferrooxidans.
6. The composition of claim 1 or 5 or the method of any one of claims 2-5, wherein the source of nitrogen is urea, an amino acid, or ammonia, such as (NH4)2SO4, NH4C1, NH4NO3, (NH4)3PO4, NH4HCO3, and (NH4)2CO3, the source of magnesium is MgSO4, MgCl2, MgF2, MgBr2, Mgl2, or Mg(NO3)2, the source of potassium is KC1, KF, KBr, KI, K2SO4, KH2PO4, K2HPO4, K3PO4, or KNO3, the source of phosphate is NH4H2PO4, (NH4)2HPO4, (NH4)3PO4, LiH2PO4, Li2HPO4, Li3PO4, NaH2PO4, Na2HPO4, Na3PO4, KH2PO4, K2HPO4, or K3PO4, the source of calcium is Ca(NO3)2, CaCl2, CaBr2, Cal2, CaSO4, or Ca3(PO4)2, and the source of iron is iron powder or stainless- steel powder.4919-4877-2747, v. 1Docket No. BCOT-OIO-WOI BC2025.014.wan -27-7. The method of claim 6, wherein the iron powder or stainless-steel powder is obtained from the spent LIB.
8. The method of any one of claims 2-7, wherein the acidification step is accomplished by adding H2SO4, HC1, HF, HBr, HI, HNO3, H3BO3, HC1O4, or H3PO4.
9. The method of any one of claims 3-8, wherein the culturing step is carried out until a concentration of Fe3+reaches at least 1 g / L, preferably at least 2 g / L, and more preferably from 3 g / L to 6 g / L.
10. The method of any one of claims 4-9, wherein the one or more metals are selected from the group consisting of Li, Mn, Ni, Co, Al, Cu, Zn, Pb, Cd, Ag, Fe, and Hg.
11. The method of claims 4-10, wherein a percent recovery of the one or more metals is from 65% to 99%, preferably above 75%, and more preferably above 80%, as compared to the percent recovery achieved by dissolving the spent LIB material in aqua regia.
12. The method of any one of claims 2-11, wherein the incubating step is carried out at 20°C to 35°C, preferably at 30°C.
13. A method for recycling a spent LIB, the method comprising grinding the spent LIB into a powder, mixing it with the composition of any one of claims 1, 5, and 6, and recovering one or more metals from the spent LIB.
14. The composition of any one of claims 1, 5, and 6 or the method of claim 13, wherein a concentration of Fe3+in the composition is at least 1 g / L, preferably at least 2 g / L, and more preferably 3 g / L to 6 g / L.4919-4877-2747, v. 1Docket No. BCOT-OIO-WOI BC2025.014.wan -28-15. The method of claim 13 or 14, wherein the one or more metals recovered from the spent LIB are selected from the group consisting of Li, Mn, Ni, Co, Al, Cu, Zn, Pb, Cd, Ag, Fe, and Hg.4919-4877-2747, v. 1