JP-7855805-B2 - Regenerated cathode active material

Inventors

• セ・ホ・パク
• サンヒョン・イ
• ジェスン・キム
• ジョン・ミ・チェ
• ジョンベ・イ
• サンムン・ナ

Assignees

• エルジー エナジー ソリューション リミテッド

Dates

Publication Date

20260508

Application Date

20241023

Priority Date

20231106

Claims (5)

1. A regenerated cathode active material comprising one or more selected from the group consisting of lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate compound, lithium nickel cobalt aluminum oxide, lithium nickel oxide, nickel-manganese lithium composite metal oxide in which a portion of the nickel (Ni) in lithium nickel oxide is replaced with manganese (Mn), and NCM-based lithium composite transition metal oxide in which a portion of the nickel (Ni) in lithium nickel oxide is replaced with manganese (Mn) and cobalt (Co), The aforementioned regenerated cathode active material is finished by surface doping with a dopant without a coating layer. The regenerated cathode active material is a regenerated cathode active material in which the amount of dopant elements coated on the surface without doping is 10 ppm or less, based on EDS surface mapping.
2. The regenerated cathode active material according to claim 1, wherein the dopant is present in an amount of 100 to 2000 ppm relative to the total weight of the regenerated cathode active material.
3. The regenerated positive electrode active material according to claim 1, wherein the dopant is one or more selected from the group consisting of B, Ti, S, Na, Nb, P, Al, F, Mg, Mn, K, Y, Si, Sn, W, C, and N.
4. The regenerated cathode active material according to claim 1, wherein the regenerated cathode active material contains 40-45% by weight of carbon, 25-30% by weight of oxygen, and 25-30% by weight of nickel, based on EDS surface mapping.
5. A secondary battery comprising the regenerated positive electrode active material according to any one of claims 1 to 4.

Description

[Cross-reference with related applications] This application is an application claiming priority rights based on Korean Patent Application No. 10-2023-0152017 dated November 6, 2023, and Korean Patent Application No. 10-2024-0144952, refiled thereunder on October 22, 2024, and all contents disclosed in the documents of said Korean Patent Application are incorporated herein by reference. This invention relates to a method for regenerating a positive electrode active material and a regenerated positive electrode active material produced thereby. More specifically, it relates to a method for regenerating a positive electrode active material in which the capacity characteristics and life characteristics are improved and the regenerated positive electrode active material has excellent crack resistance, by doping the regenerated positive electrode active material with a predetermined dopant in a predetermined manner, and to a regenerated positive electrode active material produced thereby. Furthermore, this invention relates to a method for regenerating positive electrode active material that is environmentally friendly because it does not use acid, reduces process costs because neutralization and wastewater treatment are not required, regenerates the positive electrode active material without decomposing it, eliminates the disposal of metal elements, does not dissolve the current collector and allows for its recovery, does not use organic solvents and therefore eliminates the risk of generating toxic gases or explosions, and is suitable for mass production by using a process that is easy to manage, such as heat treatment and sedimentation. The invention also relates to a regenerated positive electrode active material produced therefrom that exhibits excellent electrochemical performance, resistance characteristics, and capacitance characteristics. Lithium-ion batteries are broadly classified into several components: a positive electrode, where the positive electrode active material layer is coated with metal foil such as aluminum; a negative electrode, where the negative electrode active material layer is coated with metal foil such as copper; a separation membrane to prevent the positive and negative electrodes from mixing; and an electrolyte that allows lithium ions to move between the positive and negative electrodes. The positive electrode active material layer primarily uses lithium-based oxides as its active material, and the negative electrode active material layer primarily uses carbon materials as its active material. However, since lithium-based oxides generally contain rare metals such as cobalt, nickel, or manganese, much research is being conducted on recovering and reusing these rare metals from the positive electrodes of lithium secondary batteries that are discarded after use, or from positive electrode scrap generated during the manufacturing process of lithium secondary batteries (hereinafter referred to as "waste positive electrodes"). Conventional techniques for recovering rare metals from spent cathodes mostly involve dissolving the cathode in hydrochloric acid, sulfuric acid, or nitric acid, then extracting cobalt, manganese, nickel, etc., with an organic solvent, and using these as raw materials again for the synthesis of cathode active materials. However, acid-based extraction methods for rare metals have environmental pollution problems, requiring neutralization and wastewater treatment processes, which significantly increase process costs. Furthermore, they have the drawback of failing to recover lithium, the main metal in the cathode active material. To overcome these drawbacks, recent research has focused on direct recycling methods for regenerating cathode active material directly from waste cathodes without decomposition. Approximately four main types of such methods have been introduced: calcination, solvent dissolution, aluminum foil dissolution, and crushing and screening. However, although the aforementioned firing method is simple in its process, it has drawbacks such as the generation of foreign matter on the surface of the regenerated positive electrode active material that reduces the output performance of the battery, the generation of waste gas, and high energy consumption. In particular, removing foreign matter such as LiF requires the use of excessive initial washing water, making it difficult to apply to the regeneration process. Furthermore, not only is the same amount of waste water generated, but major problems arise such as the loss of Li in the functional coating layer and lattice of the regenerated positive electrode active material due to washing, and an increase in the occurrence of cracks that reduce the output performance of the secondary battery. Of these, by-products generated during the degradation process can be removed by washing with water, and the loss of Li can be overcome to some extent by replenishing the Li source, but the physically generated crack