FROM EV BATTERY RECYCLING TO COMMERCIAL-SCALE PRODUCTION OF LITHIUM-ION BATTERY PRECURSOR (PCAM) USING GREEN SOLUTION

Abstract

The present invention pertains to a sustainable and efficient method for recycling lithium-ion batteries (LIBs) and producing lithium-ion battery precursor (pCAM) cathode precursors. In the recycling aspect, the invention introduces a green solvent mixture comprising Ethylene glycol phosphite (2-hydroxyethyl dihydrogen phosphite) and water, and not limited to the mixture Ethylene glycol, H.sub.3PO.sub.4 and water (H.sub.2O) or a mixture of Ethylene glycol, H.sub.2SO.sub.4 and water H2O, for leaching valuable metal ions from spent cathodes and ore minerals. This method exhibits outstanding extraction efficiency, with 99.9% recovery rates for nickel, cobalt, manganese, and 99.5% for lithium. In the pCAM synthesis aspect, a novel method that produces pCAM in the spherical hydroxide form using ammonium metal (ii) sulfate hexahydrate (NH4).sub.2M(SO4).sub.2.Math.6H2O, where M represents nickel(II), manganese(II), and cobalt(II), or combinations thereof.

Claims

1. A method for recycling lithium-ion batteries (LIBs), comprising: a. Collecting spent LIBs, particularly those containing cathodes of NMC111, NMC622, NMC811, NCA, or LCoO.sub.2 and LiNi.sub.0.5Mn.sub.1.5O.sub.4 compositions; b. Shredding the collected spent LIBs to facilitate further processing; c. Subjecting the shredded material to a green solvent mixture, comprising Ethylene glycol phosphite (2-hydroxyethyl dihydrogen phosphite) and water and not limited to the mixture of Ethylene glycol (EG), H.sub.3PO.sub.4 and water (H.sub.2O) or a mixture of Ethylene glycol (EG), H.sub.2SO.sub.4 and water (H.sub.2O) or a mixture of Ethylene glycol (EG), HCl and water (H.sub.2O), or a mixture of Ethylene glycol, HNO.sub.3 and water (H.sub.2O), at elevated temperatures (80-120 C.) to leach valuable metal ions from the spent cathodes and ore minerals.

2. The method of claim 1 and further comprising separating any remaining unreacted carbon black films from the metal leachate, and maintaining the collected metal leachate at room temperature and adding an extra chemical, such as (NH.sub.4).sub.2SO.sub.4, to facilitate coprecipitation.

3. The method of claim 2 and further comprising thereby forming ammonium metal(ii) sulfate hexahydrate (NH4).sub.2M(SO4).sub.2.Math.6H2O, where M represents nickel(II), manganese(II), and cobalt(II), or combinations thereof.

4. The method of claim 3 wherein said method achieves exceptional efficiency with a 99.9% extraction rate for nickel(II), manganese(II), and cobalt(II), and a 99.5% efficiency for lithium.

5. A method for synthesizing lithium-ion battery precursor (pCAM) cathode precursors in the spherical hydroxide form, comprising using ammonium metal(ii) sulfate hexahydrate (NH4).sub.2M(SO4).sub.2.Math.6H2O, where M represents nickel(II), manganese(II), and cobalt(II), or combinations thereof.

6. The method of claim 5 and further comprising producing pCAM hydroxide precursor powder by separating the pCAM hydroxide precursor powder from the aqueous medium, washing and filtering the pCAM hydroxide precursor powder; drying the filtered pCAM hydroxide precursor powder in a vacuum oven at 120 C. for several hours.

7. The method of claim 6 and further comprising mixing stoichiometric amounts of Li.sub.2OH with the dried pCAM hydroxide precursor powder.

8. The method of claim 7 and further comprising performing calcination under O.sub.2 atmospheres to yield high-quality pCAM suitable for use in lithium-ion batteries sequential order.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0021] FIG. 1 illustrates the lab equipment used to take shredded spent LIBs 1 and subject them to a green solvent mixture 5 of glycol phosphite (specifically, 2-hydroxyethyl dihydrogen phosphite) and water not limited to the mixture of Ethylene glycol(EG), phosphite acid (H.sub.3PO.sub.3) and water (H.sub.2O) or phosphite acid (H.sub.3PO.sub.3) and water (H.sub.2O), efficiently leaching valuable ions from the spent LIBs 1. The leaching takes place at elevated temperatures (80-120 C) 6 ensuring the dissolution and extraction of precious metals while leaving undissolved solid graphite 2 in the solution as illustrated in FIG. 1. The collected metal leachate 11 consisting of nickel (Ni), manganese (Mn), cobalt (Co) and Lithium (Li) (shown in FIG. 3) streaming down to the next tank. First the nickel (Ni) is separated from metal leachate 11 at room temperature (RT) 9, where coprecipitation occurs by adding (NH.sub.4).sub.2SO.sub.4. 3. The coprecipitation results in the formation of ammonium metal (ii) sulfate hexahydrate (NH.sub.4).sub.2M(SO.sub.4).sub.2.Math.6H.sub.2O 8, where M represents nickel(II), manganese(II), and cobalt(II), or combinations thereof. The precipitate is trapped and removed by the filtration unit 7, the remaining solution 12 containing manganese (Mn), and cobalt (Co) and Lithium (Li) streaming down to the next tank. The solution 12 is maintained at 60 C. 13 and through the introduction of an oxidizing agent (NH.sub.4).sub.2S.sub.2O.sub.8, 10, coprecipitation occurs. Mn.sup.2+ in the leachate 12 is oxidized and precipitated of manganese dioxide MnO.sub.2 14. Manganese dioxide (MnO.sub.2) 14, is a valuable precipitate that can have various applications, including as a component in battery cathodes, water treatment processes, and as a catalyst in certain chemical reactions. This precipitation step is crucial for the selective removal and recovery of manganese (Mn) from the leachate 12, preventing it's continued presence in the leachate 12. Then manganese dioxide 14 is continually added to mixture of (NH.sub.4).sub.2SO.sub.4 and H.sub.2SO.sub.4 15 solution to prepare ammonium manganese (ii) sulfate hexahydrate (NH.sub.4).sub.2Mn(SO.sub.4).sub.2.Math.6H.sub.2O 16. The remaining leachate 17 consisting of cobalt (Co) and Lithium (Li) streaming down to the next tank, is subsequently maintained at room temperature (RT) 18, where coprecipitation occurs by adding (NH.sub.4).sub.2S.sub.2O.sub.8, (NH).sub.2CO.sub.3, NH.sub.4OH to the remaining solution to create the ammonium Nickel(ii) sulfate hexahydrate (NH.sub.4).sub.2Co(SO.sub.4).sub.2.Math.6H.sub.2O, CoCO.sub.3 and Co(OH).sub.2 19. The remaining leachate 20 consisting of Lithium (Li) solution, is subsequently maintained at 60 C. 21 to precipitate and crystallize the mixture of Li.sub.2SO.sub.4 and NH.sub.4LiSO.sub.4, which is trapped and removed by the filtration unit 22 with the remaining solution streaming down to the next tank. The remaining solution is subsequently maintained at 70 C. to crystallize (NH.sub.4).sub.2SO.sub.4, trapped and removed by the filtration unit with the remaining solution streaming down to the next tank. This controlled temperature is conducive to the formation of well-defined crystals of ammonium sulfate, a key step in the coprecipitation method. The crystallized ammonium sulfate obtained at this temperature exhibits desirable characteristics that can be advantageous for subsequent coprecipitation processes. These crystals, once formed, can be utilized as a precursor material in various coprecipitation methods. The remaining solution is subsequently maintained at 80 C. to crystallize (NH.sub.4).sub.3Al(H.sub.3PO.sub.3).sub.6 trapped and removed by the filtration unit. The (NH.sub.4).sub.3Al(H.sub.3PO.sub.3).sub.6 is a bio-product with versatile applications in water treatment.

[0022] FIG. 2 illustrates three examples of FIG. 1 showing a 99.9% extraction rate efficiency for nickel(II), manganese(II), and cobalt(II), and a 99.5% extraction rate efficiency for lithium.

[0023] FIG. 3 illustrates the jars of first, the green solvent solution 5, then the jar of metal leachate 11, then the jar of nickel precipitate 3, then the jar of cobalt solution 18 and finally the jar of lithium solution 20. Underneath the jars the dried precipitate is shown with first small jars of the precipitate, and then pieces of paper with dried precipitate smeared on the paper

[0024] FIG. 3A illustrates the jars of first, the green solvent solution 5, then the jar of metal leachate 11, then the jar of nickel precipitate 3, then the jar of cobalt/manganese solution 40 and the jar of manganese solution 14, then the jar of cobalt/lithium solution 42 and finally the jar of lithium solution 20. The jars of cobalt/manganese solution 40 and cobalt/lithium solution 42 are intermediaries of the desired precipitants, manganese 14, cobalt 19 and lithium. Underneath the solution jars the dried precipitate is shown smeared on the paper nickel 3, manganese 14, cobalt, and finally lithium.

[0025] FIG. 4A-4C illustrate a synthesis flow chart detailing materials production via a continuous stirred tank reactor (CSTR) 30. A novel synthesis process for pCAM in the spherical hydroxide form using ammonium metal(ii) sulfate hexahydrate (NH4).sub.2M(SO4).sub.2.Math.6H2O 32, where M represents nickel(II) 3, manganese(II) 14, and cobalt(II) 19, or combinations thereof as metal source and ammonium (NH4) chelating agent is disclosed. The flow rate for the ammonium metal(ii) sulfate hexahydrate (NH4).sub.2M(SO4).sub.2.Math.6H2O 32, which is Solution A, is 0.5 l/hr. The flow rate for the sodium hydroxide NaAlO.sub.2, Solution B, is 0.5 l/hr. Solution C 33 which is sodium hydroxide in DI water is used to maintain a pH of 11. There is continuous collection of cathode product 34. The CSTR 30 is operated 600 rpm at 55 C. The CSTR 30 is shown schematically on the left, then drawn connected up to the necessary controls on the right, then photographs of the CSTR 30 are shown below. The resulting pCAM hydroxide precursor powder is separated from the aqueous medium, washed, and, after filtration, dried in a vacuum oven at 120 C. for several hours. Stoichiometric amounts of Li.sub.2OH 20 are mixed with the prepared cathode material, followed by calcination under O.sub.2 atmospheres, yielding high-quality cathode material for use in lithium-ion batteries.

DETAILED DESCRIPTION OF THE INVENTION

[0026] The invention encompasses a novel and sustainable method for recycling lithium-ion batteries (LIBs) and producing high-quality lithium-ion battery precursor (pCAM). This method overcomes the limitations of traditional recycling processes and addresses the challenges associated with synthesizing pCAM cathode precursors using ammonia.

[0027] The recycling process begins with the collection and shredding of spent LIBs 1, particularly those containing cathodes such as (e.g., NMC111, NMC523, NMC622, NMC811, NCA, NMA, NMCA, LiNiO.sub.2, LiFeO.sub.2, LizMnO.sub.3, LCoO.sub.2 or LiNi.sub.0.5Mn.sub.1.5O.sub.4). The shredded material 1 is then subjected to a green solvent mixture 5, consisting of Ethylene glycol phosphite (specifically, 2-hydroxyethyl dihydrogen phosphite) and water and not limited to the mixture Ethylene glycol, H.sub.3PO.sub.3 and water (H.sub.2O) or mixture of H.sub.3PO.sub.3 and water H.sub.2O. This environmentally friendly mixture 5 facilitates efficient leaching of valuable metal ions from the spent cathodes 1, nickel-metal hydride battery (NiMH or NiMH) and ore minerals. The leaching process takes place at elevated temperatures (80-120 C.) 6, ensuring the dissolution and extraction of precious metals while leaving undissolved solid graphite 2 in the solution. Thanks to the high boiling point of Ethylene glycol and H.sub.3PO.sub.3 5 as oxidizing agent, leaching is accomplished within approximately one hour under these conditions.

[0028] After completion of the leaching process, any remaining unreacted graphite 2 and or carbon black 2 is trapped and removed by the filtration unit 7 with the remaining metal solution 11 streaming down to the next tank.

[0029] Ni separation process: The collected metal leachate consisting of nickel (Ni), manganese (Mn), cobalt (Co) and Lithium (Li), 11 is subsequently maintained at room temperature (RT) 9, where coprecipitation occurs by adding (NH.sub.4).sub.2SO.sub.4 3. The coprecipitation mechanism facilitates the simultaneous precipitation with high selectivity of ammonium Nickel (ii) sulfate hexahydrate (NH.sub.4).sub.2Ni(SO.sub.4).sub.2.Math.6H.sub.2O 8. The precipitate 8 is trapped and removed by the filtration unit 7, the remaining solution containing manganese (Mn), and cobalt (Co) and Lithium 12 streaming down to the next tank.

[0030] The remaining solution consisting of manganese (Mn), cobalt (Co) and Lithium (Li), 12 is subsequently maintained at 60 C. 13, where coprecipitation occurs by adding (NH.sub.4).sub.2S.sub.2O.sub.8 10 to the leaching solution 12. Mn.sup.2+ in the leachate is oxidized and precipitated of manganese dioxide MnO.sub.2. 14. The precipitation reaction takes place is: Mn.sup.2++S.sub.2O.sub.8.sup.2+2H.sub.2.fwdarw.MnO.sub.2+2SO.sub.4.sup.2+4H.sup.8. The precipitate 14 is trapped and removed by the filtration unit 7 and the remaining solution 17 containing manganese (Mn), and cobalt (Co) and Lithium streaming down to the next tank. Then the manganese dioxide MnO.sub.2 14 is continually added to mixture of (NH.sub.4).sub.2SO.sub.4 and H.sub.2SO.sub.4 15 solution to prepare ammonium manganese (ii) sulfate hexahydrate (NH.sub.4).sub.2Mn(SO.sub.4).sub.2.Math.6H.sub.2O 23.

[0031] The remaining solution 17 consisting of cobalt (Co) and Lithium (Li), is subsequently maintained at room temperature 18, where coprecipitation occurs by adding (NH.sub.4).sub.2S.sub.2O.sub.8, (NH.sub.4).sub.2CO.sub.3, NH.sub.4OH to the remaining solution to create the ammonium Nickel(ii) sulfate hexahydrate (NH.sub.4).sub.2Co(SO.sub.4).sub.2.Math.6H.sub.2O 19, CoCO.sub.3 and Co(OH).sub.2.

[0032] The remaining solution consisting of Lithium (Li) solution 20, is subsequently maintained at 60 C. 21 to precipitate and crystallize the mixture of Li.sub.2SO.sub.4 and NH.sub.4LiSO.sub.4 27, trapped and removed by the filtration unit 22 with the remaining solution 24 streaming down to the next tank. The remaining solution 24 is subsequently maintained at 80 C. to crystallize (NH.sub.4).sub.2SO.sub.4, which is trapped and removed by the filtration unit with the remaining solution streaming down to the next tank.

[0033] The remaining solution is subsequently maintained at 80 C. to crystallize (NH.sub.4).sub.3Al(H.sub.3PO.sub.3).sub.6, trapped and removed by the filtration unit. The (NH.sub.4).sub.3Al(H.sub.3PO.sub.3).sub.6 is a bio-product with versatile applications in water treatment.

Ammonia-Free Process for Synthesis of pCAM Cathode Precursors

[0034] The invention also addresses the challenges associated with traditional methods of synthesizing pCAM cathode precursors, which rely on ammonia as a chelating agent. This conventional approach uses co-precipitation in a Continuous Stirred Tank Reactor (CSTR) 30 to form precursors in their carbonate or hydroxide forms, requiring significant quantities of ammonia, water, and generating hazardous waste.

[0035] The invention seeks to provide an alternative method that eliminates the reliance on ammonia, offering a more efficient, environmentally friendly, and practical approach to synthesizing pCam cathode precursors. By addressing these challenges, the innovation not only enhances the sustainability of the synthesis process but also improves the overall feasibility of scalability of producing pCam materials for various applications, particularly in the field of energy storage and catalysis. To overcome these challenges, the invention introduces a novel synthesis process for pCAM in the spherical hydroxide form using ammonium metal (ii) sulfate hexahydrate (NH.sub.4).sub.2M(SO.sub.4).sub.2.Math.6H.sub.2O, 32 where M represents nickel(II), manganese(II), and cobalt(II), or combinations thereof as metal source and ammonium (NH.sub.4) chelating agent which is the key for this eco-friendly and cost-effective process. This innovative method eliminates the need for ammonia as a chelating agent, reducing pCAM production costs and environmental impact.

[0036] To produce active materials featuring NMC111, NMC523, NMC622, NMC811, the initial step involves preparing a solution of 2M ammonium metal(ii) sulfate hexahydrate 31 recovered from recycling of lithium-ion batteries denoted as (NH.sub.4).sub.2M(SO.sub.4).sub.2.Math.6H.sub.2O 32 where M represents nickel(II), manganese(II), and cobalt(II), or combinations thereof. A metal salt solution with a precisely calculated stoichiometric amount is meticulously formulated. Subsequently, 4 liters of distilled water are introduced into a CSTR reactor 30, boasting a capacity of 5 liters and powered by an 80 W rotation motor. Nitrogen gas is then introduced into the reactor at a rate of 0.5 liters per minute to eliminate dissolved oxygen. The stirring process commences at 800 rpm, maintaining a reactor 30 temperature of 50 C. throughout. This carefully orchestrated sequence of steps establishes the foundation for the synthesis of active materials with the specified NMC compositions. The initial metal salt solution 32 was consistently introduced into the reactor at a continuous rate of 0.3 liters per hour, complemented by a continuous infusion of 2M NaOH solution 31 also at a rate of 0.3 liters per hour. Additionally, to maintain the desired pH level at 11, a 4M sodium hydroxide (NaOH) solution 33 was continuously supplied for pH adjustment. The impeller speed of the reactor 30 was carefully regulated at 1000 rpm to facilitate the homogeneous coprecipitation reaction. Once the reaction had achieved a stable state, a duration of 12 hours in normal status was allotted to the reactants, ensuring the production of a coprecipitation composite with enhanced density.

[0037] The resulting pCAM hydroxide precursor powder is separated from the aqueous medium, washed, and, after filtration, dried in a vacuum oven at 120 C. for several hours. Subsequently, stoichiometric amounts of Li.sub.2OH 20 are mixed with the prepared cathode material, followed by calcination under O.sub.2 atmospheres, yielding high-quality cathode material for use in lithium-ion batteries.

[0038] Another embodiment according to this invention is a coprecipitation method to prepare the spherical NMCA(OH)2 precursor. The co-precipitation of Ni2+, Mn2+, or Co2+ with Al3+ proved challenging due to the significantly smaller Ksp of Al(OH)3 compared to Ni(OH)2, Mn(OH)2, and Co(OH)2. To address this issue, AlO.sup.2 was employed as the aluminum source, capable of hydrolyzing into Al(OH)3 under specific pH conditions, ensuring the simultaneous co-precipitation of Ni2+, Mn2+, Co2+ and Al3+. The experimental setup involved a continuous stirred tank reactor (CSTR) 30 with a 5 L capacity operating under an N2 atmosphere. In the CSTR 30, 5 L of 1M NaOH solution was added and maintained at 55 C. Three types of solutions, designated as solution A 32, solution B 31, and solution C 33, were used. Solution A 32 comprised of a mixture of (NH4)2M(SO4)2.6H2O 32, where M represents nickel (II), manganese (II), cobalt (II) at a concentration of 2.0 M in deionized water. Solution B 31, totaling 5 L, resulted from the combination of NaALO2, NaOH (2.0 M) in deionized water. The elevated NaOH concentrations facilitated the conversion of Al3+ into AlO2. Finally, solution C 33 was prepared as a 2.0 M NaOH solution. Solution A 32 and solution B 31 were added into the CSTR 30 with the 2 ml/min and 5 ml/min flow rate respectively. The pH of the mixed solution in the CSTR 30 was maintained at 11.50.2 by controlling the flow rate of solution C 33. The stirring speed and temperature of the solution in the CSTR 30 were controlled strictly. The resultant NMCA 34 precursor powder was filtered then washed with deionized water several times until the pH of the filtrate was close to 7.0. After sieving, powders with an average particle size of 10 um were used for further analyses. The Ni, Al and Fe contents of the as-prepared sample was 8:1:1 respectively, as confirmed by inductively coupled plasma-mass spectroscopy ICP-MS-analysis. The filtered powder was dried at 120 C. for overnight and then fired with appropriate amount of Li2CO3 at 700 C. and 750 C. for 20 hours under O2 to make NMCA 34.