Active material recovery method using positive electrode scrap

Patent metadata

Field	Value
Publication number	US-2023275278-A1
Application number	US-202118016217-A
Country	US
Kind code	A1
Filing date	Jun 29, 2021
Priority date	Aug 24, 2020
Publication date	Aug 31, 2023
Grant date	—

Abstract

A method of recovering an active material from a positive electrode scrap and reusing the active material is provided. The method includes (a) heat treating a positive electrode scrap including a positive electrode active material layer on a current collector in air to thermally decompose a binder and a conductive material in the positive electrode active material layer, separating the current collector from the positive electrode active material layer, and recovering an active material in the positive electrode active material layer, wherein the active material comprises a lithium composite transition metal oxide; (b) washing the recovered active material with a cleaning solution; (c) adding a lithium precursor to the washed active material and annealing the active material; and (d) optionally performing surface coating on the annealed active material and obtaining a reusable active material, wherein an amount of the lithium precursor added in step (c) is determined so that an amount of a remaining lithium compound in the reusable active material is 0.0001 to 1.2 wt %.

First claim

1 . A method for recovering a positive electrode active material, comprising:
(a) heat treating a positive electrode scrap including a positive electrode active material layer on a current collector in air to thermally decompose a binder and a conductive material in the positive electrode active material layer, separating the current collector from the positive electrode active material layer, and recovering an active material in the positive electrode active material layer, wherein the active material comprises a lithium composite transition metal oxide; (b) washing the recovered active material with a cleaning solution; (c) adding a lithium precursor to the washed active material and annealing the active material; and (d) optionally performing surface coating on the annealed active material, and obtaining a reusable active material, wherein an amount of the lithium precursor added in step (c) is determined such that an amount of a remaining lithium compound in the reusable active material is 0.0001 to 1.2 wt %.

2 . The method of claim 1 , wherein heat treating is performed for 10 minutes to 24 hours at 300 to 650° C.

3 . The method of claim 1 , wherein:
the cleaning solution is a lithium compound aqueous solution showing basicity in an aqueous solution state, the lithium compound aqueous solution contains a lithium compound more than 0% and equal to or less than 15%, and the washing step (b) is performed within one week.

4 . The method of claim 3 , wherein washing is performed by impregnating the recovered active material in the lithium compound aqueous solution and at the same time stirring the recovered active material.

5 . The method of claim 1 , wherein the lithium precursor comprises at least one of LiOH, Li 2 CO 3 , LiNO 3 and Li 2 O.

6 . The method of claim 1 , wherein the lithium precursor is added by an amount that corresponds to a molar ratio of 0.09 to 0.12 of lithium further added with respect to a molar ratio of lithium to other metals in the recovered active material of 1:1.

7 . The method of claim 1 , wherein, without drying after the washing, the lithium precursor is added in step (c) by mixing the washed active material in a lithium precursor solution and spray drying the active material.

8 . The method of claim 7 , wherein a temperature of the spray drying is 100 to 300° C.

9 . The method of claim 1 , wherein the annealing is performed at 400 to 1000° C. in air.

10 . The method of claim 1 , wherein a temperature of the annealing exceeds a melting point of the lithium precursor.

11 . The method of claim 1 , wherein the active material in the active material layer is recovered in powder form, and a carbon component generated by carbonization of the binder or the conductive material does not remain on a surface.

12 . The method of claim 2 , wherein the surface coating includes a coating of at least one of a metal, an organic metal and a carbon component on a surface of the annealed active material using a solid or liquid method, and then performing heat treatment at 100 to 1200° C.

13 . The method of claim 1 , wherein the reusable active material is represented by Chemical Formula 1 below,
Li a Ni x Mn y Co z M w O 2+δ   (1)
wherein M includes at least one selected from the group consisting of B, W, Al, Ti and Mg, 1<a≤1.1, 0≤x<0.95, 0≤y<0.8, 0≤z<1.0, 0≤w≤0.1, −0.02≤δ≤0.02, and x+y+z+w=1.

14 . The method of claim 1 , wherein the reusable active material includes a content of fluorine (F) equal to or less than 100 ppm.

Assignees

• Lg Energy Solution Ltd

Inventors

• Kim Min-Seo
• Park Se-Ho
• Yang Doo-Kyung

Classifications

• H01M10/54 Primary

  Reclaiming serviceable parts of waste accumulators · CPC title

• H01M4/505

  of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy · CPC title

• H01M4/525

  of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy · CPC title

• H01M4/0471

  involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis · CPC title

• H01M2004/028

  Positive electrodes · CPC title