TECHNICAL FIELD
Cross-reference to Related Applications
[0001] This application claims the benefit of Korean Patent Application No. 10-
2020-0116722, filed on September 11, 2020, in the Korean Intellectual Property
Office, the disclosure of which is incorporated herein in its entirety by reference.
10 Technical Field
[0002] The present invention relates to a method for recycling a positive
electrode material in a secondary battery. More specifically, the present invention
relates to a method for efficiently recycling a positive electrode material to an extent
close to an original form thereof from a secondary battery, using a solution or powder
15 containing sodium ions in a heat-treatment process.
BACKGROUND ART
[0003] Lithium secondary batteries provide benefits such as high energy density,
high electromotive force, and high capacity, and thus are widely used in various
20 industrial fields. For example, lithium secondary batteries are being applied to
various products from small portable devices such as smartphones and laptops to
electric vehicles (EVs) that are expected to replace current fossil-fuel-powered
vehicles in the future, and accordingly, there is a growing number of lithium
secondary batteries scrapped after reaching their service life as well.
25 [0004] Meanwhile, lithium, a core component of lithium secondary batteries, is
2
2
generally processed from ore containing lithium, the cost for manufacturing
processes and the price of the raw material itself bring about lithium metals with a
relatively high price tag when traded. Accordingly, in addition to studies on the
performance of lithium secondary batteries themselves, there is also a high demand
5 for research on methods for efficiently recycling lithium from a gradually increasing
number of used lithium secondary batteries.
[0005] Currently, a commonly known method for recycling lithium from lithium
secondary batteries includes a method designed to separate a positive electrode
active material from a lithium secondary battery, dissolve positive electrode active
10 material powder through a sulfuric acid leaching process, and then sequentially use
a solvent extractant to separate various metals, but in the case, a large amount of
sodium compounds are used in the extraction process, and that serves as an
obstacle to eventually separating sodium and lithium with high purity. The case
comes with poor economic feasibility in that lithium components are obtained in the
15 form of raw materials, which requires a process for manufacturing a positive
electrode material from the beginning in order to use the lithium components for
lithium secondary batteries. In response, studies have been conducted lately on a
direct recycling method designed to keep the original form of positive electrode
material powder and solely remove impurities to use the obtained again as a positive
20 electrode material instead of performing typical recycling processes such as
leaching/extraction/purification/crystallization by recovering positive electrode
material powder from secondary batteries or positive electrodes.
[0006] [Related Art Document](Patent Document 1) KR 10-1682217
25 DISCLOSURE OF THE INVENTION
3
3
TECHNICAL PROBLEM
[0007] To solve the tasks described herein, the present invention provides a
method for recycling a positive electrode material included in a secondary battery
without loss of an original form thereof.
5 [0008] Specifically, the present invention provides a method mixing positive
electrode material particles with a solution or powder containing sodium ions and
heat-treating the mixture to minimize the loss of lithium components in a positive
electrode material and to maximally remove fluorine components on a surface of the
positive electrode material, thereby recycling the positive electrode material.
10
TECHNICAL SOLUTION
[0009] According to an aspect of the present invention, there is provided a
method for recycling a positive electrode material, the method including: obtaining
positive electrode material particles from a positive electrode (S1); mixing the
15 positive electrode material particles with a solution or powder containing sodium
ions and heat-treating the mixture (S2); and rinsing the heat-treated positive
electrode material particles with water (S3).
ADVANTAGEOUS EFFECTS
20 [0010] When a method for recycling a positive electrode material is applied as
provided herein, positive electrode material particles are mixed with a solution or
powder containing sodium ions and then heat-treated to remove fluorine
components of a fluorine-based polymer binder remaining on a surface of the
positive electrode material in the form of sodium fluoride instead of lithium fluoride,
25 thereby minimizing the loss of lithium to recycle the positive electrode material.
4
4
[0011] In addition, when a method for recycling a positive electrode material is
applied as provided herein, generation of hydrogen fluoride, which may act as a
strong acid upon heat-treatment, may be prevented to allow the positive electrode
material to be recycled without adversely affecting equipment durability.

CLAIMS
1. A method for recycling a positive electrode material, the method comprising:
obtaining positive electrode material particles from a positive electrode (S1);
5 mixing the positive electrode material particles with a solution or powder
containing sodium ions and heat-treating the mixture (S2); and
rinsing the heat-treated positive electrode material particles with water (S3).
2. The method of claim 1, wherein the step S1 comprises:
10 crushing the positive electrode of a lithium secondary battery (S1-1); and
classifying the crushed particles to separate the positive electrode material
particles from collector particles (S1-2).
3. The method of claim 1, wherein the step S1 is performed using a chemical
15 solvent treatment method or a heat-treatment method.
4. The method of claim 1, wherein the solution or the powder containing sodium
ions is alkaline.
20 5. The method of claim 1, wherein the solution or the powder containing sodium
ions is prepared using at least one selected from the group consisting of NaOH,
Na2CO3, and NaHCO3.
6. The method of claim 1, wherein the solution or the powder containing sodium
25 ions has a sodium amount of 150% to 200% with respect to the number of moles of
25
25
F.
7. The method of claim 1, wherein the solution containing sodium ions has a
sodium concentration of 0.1 to 10 M.
5
8. The method of claim 1, wherein the heat-treatment is performed in an
oxygen-free atmosphere.
9. The method of claim 8, wherein the oxygen-free atmosphere is an
10 atmosphere having an oxygen concentration of 3 volume% or less.
10. The method of claim 8, wherein the oxygen-free atmosphere is formed by
including at least one gas selected from nitrogen, carbon dioxide, and an inert gas.
15 11. The method of claim 1, wherein the heat-treatment is performed in an
oxygen enrichment atmosphere.
12. The method of claim 11, wherein the oxygen enrichment atmosphere is an
atmosphere having an oxygen concentration of 20 volume% or greater.
20
13. The method of claim 1, wherein the heat-treatment is performed at 250 to
800 °C.