KR-20260065897-A - Direct upcycling of lithium-ion battery cathodes into single-crystal nickel-rich NCM

Abstract

The present disclosure relates to a method for upcycling spent lithium-ion battery cathodes. In some embodiments, the method may include the step of mixing delithiated NCM particles with a supplementary lithium source comprising a single lithium salt to produce single-crystal NCM particles having effective size control and improved electrochemical performance compared to the original polycrystalline NCM.

Inventors

• 천 정
• 가오 홍펑

Assignees

• 더 리젠츠 오브 더 유니버시티 오브 캘리포니아

Dates

Publication Date

20260511

Application Date

20240906

Priority Date

20230906

Claims (20)

1. As a direct upcycling method for lithium-ion battery cathodes, the method is: A step of providing delithiated NCM particles from a spent lithium-ion battery cathode; A step of producing NCM single-crystal particles by mixing delithiated NCM particles with a Ni-containing precursor; A step of mixing NCM single crystal particles with a supplementary lithium source to form a mixture, wherein the supplementary lithium source comprises a single lithium salt; and Step of processing a mixture to produce single-crystal NCM particles with increased nickel content A method including
2. A method according to claim 1, further comprising the step of re-lithiating and purifying delithiated NCM particles prior to the step of mixing with a Ni-containing precursor.
3. A method according to claim 1, wherein the single-crystal NCM particles have a nickel content of at least 60%.
4. The method according to claim 1, wherein the source of the delithiated NCM particles is D-NCM 111.
5. A method according to claim 1, wherein delithiated NCM particles are ball-milled together with a Ni-containing precursor to produce NCM single-crystal particles.
6. In claim 5, the method wherein the Ni-containing precursor comprises Ni(OH) 2 .
7. In paragraph 1, the treatment is: A step of producing pellets by pelletizing a mixture; and Step of producing pelletized single-crystal NCM particles by sintering pellets A method including
8. In claim 7, the reaction mixture is pelletized at a pressure of at least about 5 MPa.
9. In claim 7, the method wherein the mixture is pelletized at a pressure of at least about 15 MPa.
10. In claim 7, the method wherein the pellets are sintered at a temperature of about 850°C to about 950°C.
11. In paragraph 10, the method wherein the pellets are sintered at approximately 850°C.
12. In item 10, the method wherein the heating rate during sintering is about 10°C/min.
13. In paragraph 10, the pellet is sintered under pure oxygen.
14. In claim 10, the method wherein the pellets are sintered for at least about 10 hours.
15. In claim 14, the method wherein the pellets are sintered for about 10 to about 15 hours.
16. In paragraph 15, the pellets are sintered for about 12 hours.
17. In claim 10, the method wherein, during sintering, the pellet is maintained at approximately 480°C for approximately 3 hours.
18. In paragraph 17, the method wherein the heating rate during sintering is about 5°C/min.
19. The method according to claim 1, wherein the mixture comprises a molar excess of lithium salt.
20. In paragraph 19, the method wherein the mixture comprises a molar excess of at least about 5% of the lithium salt.

Description

Direct upcycling of lithium-ion battery cathodes into single-crystal nickel-rich NCM Related applications This application claims the benefit of priority of U.S. Provisional Application No. 63/536,890 filed on September 6, 2023, the entirety of which is incorporated herein by reference. Government rights The present invention was made with the support of the U.S. government under Grant No. DE-AC02-06CH-11357 granted by the U.S. Department of Energy. The U.S. government holds specific rights in the present invention. Technology field The present invention relates to the recycling, recovery, and regeneration of materials from spent lithium-ion batteries. The rapid growth in lithium-ion battery (LIB) production has met the increasing demand for portable electronic devices, electric vehicles (EVs), and grid energy storage systems. Since the 2010s, the rapid growth of EVs has been accompanied by falling LIB prices and a tremendous increase in interest in them. As these EVs inevitably reach their End of Life (EOL)—typically 8 to 10 years—a large number of spent LIBs will be generated. For these EOL batteries, which can still retain up to 80% of their original capacity, one potential solution is to reuse them in low-demand applications, such as utilities and backup power storage, to extend their useful life. Nevertheless, this approach merely postpones the ultimate need for recycling. Recycling all EOL LIBs remains a critical and urgent issue. Wet and dry smelting processes have been adopted in the state-of-the-art LIB recycling industry. These processes involve intensive energy consumption and corrosive substances, including high-temperature smelting, acid leaching, and chemical precipitation, which inevitably lead to large amounts of CO2 emissions and the generation of other waste. On the other hand, newly emerging direct recycling technologies have attracted increasing interest due to their minimal energy consumption and maximum potential benefits compared to traditional wet and dry smelting recycling methods. Efforts have been focused on healing structural and compositional defects in cathode active materials from spent LIBs, including solid-state sintering, hydrothermal treatment, ionothermal, redox mediation 15 , and short annealing processes following molten eutectic salt relithiation. While mixing all precursors in stoichiometric ratios for solid-state sintering appears to be a simple strategy on the surface, determining the amount of supplementary Li source for waste streams mixed with spent LIBs having a wide range of state of health (SOH) is difficult. In contrast, some self-saturated relithiation strategies have demonstrated high efficacy in direct recycling without considering SOH fluctuations. As the demand for high-energy-density LIBs increases, improving the performance of spent cathode active materials beyond that of the original materials through recycling processes remains a challenging task and a significant milestone for next-generation battery recycling. Additionally, single-crystal LiNi x Co y Mn 1- x - y O 2 (NCM) cathodes have attracted increasing attention due to their superior structural stability compared to conventional polycrystalline grains. Since polycrystalline grains are susceptible to the accumulation of lattice strain and distortion caused by grain boundary evolution, an effective direct approach to eliminate grain boundary failure is to convert the polycrystalline material into a single-crystal domain, providing excellent kinetics and rate capability along with significant integrity improvements through optimized size and shape control. Recently, a molten salt method based on a LiOH-Li 2 SO 4 salt mixture has been demonstrated to upgrade polycrystalline NCM 111 and NCM 532 to single-crystal NCM 622. This concept has also been illustrated by converting waste polycrystalline LiNi 0.88 Co 0.095 Al 0.025 O 2 (NCA) into regenerated single crystals of the same composition using a LiOH-Na 2 SO 4 eutectic molten salt system. Furthermore, a mutual ternary molten salt system of LiNO 3 -NaCl was developed to upcycle waste NCM 111 into NCM 622. At the same time, the production of high-performance nickel-rich cathodes (Ni > 80%) has attracted significant interest due to their high energy output. In this regard, upgrading waste NCM 111 into single-crystal NCM 811 (or even higher Ni) is considered one of the ultimate solutions to avoid multi-stage high-temperature calcination processes using excess lithium salt or molten salt flux methods. Nevertheless, upcycling low-nickel cathodes into NCM 811 remains a challenging task. Therefore, there remains a need for sustainable end-of-life battery management to reduce greenhouse gas emissions and resource consumption in order to create a low-carbon future. The approach of the present invention relates to a method for upgrading polycrystalline delithiated NCM 111 (D-NCM 111) to single-crystal NCM 811 using LiOH as a single supplementary lithium source