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JP-2026514374-A - Method for producing a positive electrode slurry composition and method for producing a positive electrode

JP2026514374AJP 2026514374 AJP2026514374 AJP 2026514374AJP-2026514374-A

Abstract

The present invention relates to a method for producing a positive electrode slurry composition and a positive electrode, comprising the steps of (S1) putting a positive electrode active material, a conductive material, a binder, and a non-aqueous solvent into a mixer and mixing them to produce a mixture having a solid content of more than 60% by weight and a temperature of -20°C to 45°C; (S2) cooling the mixture to a temperature of -30°C to 15°C to produce a positive electrode slurry composition precursor; and (S3) maintaining the temperature of the positive electrode slurry composition precursor to produce a positive electrode slurry composition having a V 72 of 0% to 50%, wherein V n is the viscosity increase rate when the temperature of the positive electrode slurry composition precursor is maintained for n hours, and the viscosity increase rate is represented by mathematical formula 1 described herein.

Inventors

  • キュン・ロク・イ
  • ミン・キュ・ユ
  • ジュネ・ウ・イ
  • スン・チョル・ハ
  • ジ・ア・シン
  • ウン・ソン・ホ
  • ジュン・ヨプ・ド

Assignees

  • エルジー・ケム・リミテッド

Dates

Publication Date
20260511
Application Date
20240531
Priority Date
20230531

Claims (15)

  1. (S1) A step of putting a positive electrode active material, a conductive material, a binder and a non-aqueous solvent into a mixer and mixing them to produce a mixture having a solid content of more than 60% by weight and a temperature of -20°C or higher and 45°C or lower, (S2) A step of cooling the mixture to a temperature of -30°C or higher and 15°C or lower to produce a cathode slurry composition precursor, (S3) The process includes the step of maintaining the temperature of the cathode slurry composition precursor and producing a cathode slurry composition in which V72 is 0% or more and 50% or less, The V n is the viscosity increase rate when the temperature of the positive electrode slurry composition precursor is maintained for n hours. The viscosity increase rate is represented by the following mathematical formula 1, a method for producing a positive electrode slurry composition. [Mathematical formula 1] Viscosity increase rate (V n [%]) = (VS2 [cP] - VS1 [cP] × 100 / VS1 [cP]) In the above mathematical formula 1, VS1 is the viscosity [cP] of the mixture, and VS2 is the viscosity [cP] of the positive electrode slurry composition.
  2. The method for producing a positive electrode slurry composition according to claim 1, wherein the mixer has a surface temperature of -30°C or higher and 20°C or lower.
  3. The mixer includes a mixing chamber, The method for producing a positive electrode slurry composition according to claim 1, wherein the mixing is performed such that the temperature of the internal surface and the internal space of the mixing chamber are independently -30°C or higher and 20°C or lower.
  4. The method for producing a positive electrode slurry composition according to claim 1, wherein the positive electrode active material comprises one or more lithium complex transition metal compounds having compositions represented by the following chemical formulas 1 to 4. [Chemical formula 1] Li a [Ni b Co c Mn d M 1 1-(b+c+d) ]O 2 In the aforementioned chemical formula 1, M1 is one or more elements selected from the group consisting of Na, K, Mg, Al, Fe, Cr, Y, Sn, Ti, B, P, Zr, Ru, Nb, W, Ba, Sr, La, Ga, Gd, Sm, Ca, Ce, F, Ta, Mo, Sc, V, Zn, Cu, In, S, and Bi. 0.9 ≤ a ≤ 1.1, 0 < b < 1, 0 < c < 1, 0 < d < 1, 0 < b + c + d ≤ 1, [Chemical formula 2] Li e Ni 1-f M 2 f O 2 In the aforementioned chemical formula 2, M2 is one or more elements selected from the group consisting of Mn, Na, K, Mg, Al, Fe, Cr, Y, Sn, Ti, B, P, Zr, Ru, Nb, W, Ba, Sr, La, Ga, Gd, Sm, Ca, Ce, F, Ta, Mo, Sc, V, Zn, Cu, In, S, and Bi. 0.9 ≤ e ≤ 1.1 and 0 ≤ f < 1, [Chemical formula 3] Li g Ni h Mn i M 3 j O 2 In the aforementioned chemical formula 3, M3 is one or more elements selected from the group consisting of Co, Na, K, Mg, Al, Fe, Cr, Y, Sn, Ti, P, Zr, Ru, Nb, W, Ba, Sr, La, Ga, Gd, Sm, Ca, Ce, F, Ta, Mo, Sc, V, Zn, Cu, In, S, B, and Bi. 1.0 ≤ g ≤ 1.5, 0 ≤ h ≤ 0.5, 0.4 ≤ i ≤ 0.9, 0 ≤ j ≤ 0.1, [Chemical formula 4] LiFe 1-k M 4k PO 4 In the aforementioned chemical formula 4, M4 is one or more elements selected from the group consisting of Mn, Co, Na, K, Mg, Al, Cr, Y, Sn, Ti, B, P, Zr, Ru, Nb, W, Ba, Sr, La, Ga, Te, Ir, Gd, Sm, Sb, Ca, Ce, F, Ta, Mo, Sc, V, Zn, Cu, In, S, and Bi. 0 ≤ k < 1.
  5. The method for producing a positive electrode slurry composition according to claim 1, wherein the positive electrode active material comprises two or more lithium complex transition metal compounds having compositions represented by the following chemical formulas 1 to 4. [Chemical formula 1] Li a [Ni b Co c Mn d M 1 1-(b+c+d) ]O 2 In the aforementioned chemical formula 1, M1 is one or more elements selected from the group consisting of Na, K, Mg, Al, Fe, Cr, Y, Sn, Ti, B, P, Zr, Ru, Nb, W, Ba, Sr, La, Ga, Gd, Sm, Ca, Ce, F, Ta, Mo, Sc, V, Zn, Cu, In, S, and Bi. 0.9 ≤ a ≤ 1.1, 0 < b < 1, 0 < c < 1, 0 < d < 1, 0 < b + c + d ≤ 1, [Chemical formula 2] Li e Ni 1-f M 2 f O 2 In the aforementioned chemical formula 2, M2 is one or more elements selected from the group consisting of Mn, Na, K, Mg, Al, Fe, Cr, Y, Sn, Ti, B, P, Zr, Ru, Nb, W, Ba, Sr, La, Ga, Gd, Sm, Ca, Ce, F, Ta, Mo, Sc, V, Zn, Cu, In, S, and Bi. 0.9 ≤ e ≤ 1.1 and 0 ≤ f < 1, [Chemical formula 3] Li g Ni h Mn i M 3 j O 2 In the aforementioned chemical formula 3, M3 is one or more elements selected from the group consisting of Co, Na, K, Mg, Al, Fe, Cr, Y, Sn, Ti, P, Zr, Ru, Nb, W, Ba, Sr, La, Ga, Gd, Sm, Ca, Ce, F, Ta, Mo, Sc, V, Zn, Cu, In, S, B, and Bi. 1.0 ≤ g ≤ 1.5, 0 ≤ h ≤ 0.5, 0.4 ≤ i ≤ 0.9, 0 ≤ j ≤ 0.1, [Chemical formula 4] LiFe 1-k M 4k PO 4 In the aforementioned chemical formula 4, M4 is one or more elements selected from the group consisting of Mn, Co, Na, K, Mg, Al, Cr, Y, Sn, Ti, B, P, Zr, Ru, Nb, W, Ba, Sr, La, Ga, Te, Ir, Gd, Sm, Sb, Ca, Ce, F, Ta, Mo, Sc, V, Zn, Cu, In, S, and Bi. 0 ≤ k < 1.
  6. A method for producing a positive electrode slurry composition according to claim 1, wherein the positive electrode active material comprises a lithium composite transition metal compound having a composition represented by the following chemical formula 5. [Chemical formula 5] Li a' [Ni b' Co c' Mn d' M 5 1-(b'+c'+d') ]O 2 M5 is one or more elements selected from the group consisting of Na, K, Mg, Al, Fe, Cr, Y, Sn, Ti, B, P, Zr, Ru, Nb, W, Ba, Sr, La, Ga, Gd, Sm, Ca, Ce, F, Ta, Mo, Sc, V, Zn, Cu, In, S, and Bi. 0.9 ≤ a' ≤ 1.1, 0.6 ≤ b'< 1, 0 <c'< 0.4, 0 <d'< 0.4, and 0 <b' + c' + d' ≤ 1.
  7. The method for producing a positive electrode slurry composition according to claim 1, wherein the mixing is performed such that, based on 100 parts by weight of solids, the positive electrode active material is 85 parts by weight or more and 99 parts by weight or less, the conductive material is 0.5 parts by weight or more and 10 parts by weight or less, and the binder is 0.5 parts by weight or more and 10 parts by weight or less.
  8. The method for producing the positive electrode slurry composition according to claim 1, wherein the solid content is 70% by weight or more and 85% by weight or less.
  9. The method for producing a cathode slurry composition according to claim 1, wherein (S2) is the method for producing a cathode slurry composition precursor by cooling the mixture to a temperature of -30°C or higher and -23°C or lower.
  10. A method for producing a positive electrode slurry composition according to claim 1, wherein V 24 is -5% or more and 30% or less.
  11. A method for producing a positive electrode slurry composition according to claim 1, wherein V 168 is 0% or more and 80% or less.
  12. A method for producing a positive electrode slurry composition according to claim 1, wherein V 336 is present in an amount of 1% or more and 120% or less.
  13. The method for producing a positive electrode slurry composition according to claim 1, wherein the mixture, the positive electrode slurry composition precursor, and the positive electrode slurry composition each independently have a viscosity of 20,000 cP or less.
  14. (A) A step of manufacturing a positive electrode slurry composition by a manufacturing method described in any one of claims 1 to 13, (B) A method for producing a positive electrode, comprising the steps of (B) applying the positive electrode slurry composition onto a current collector and drying it to form a positive electrode active material layer.
  15. Immediately before step (B), the step (A1) further includes transferring the positive electrode slurry composition to a means for coating the positive electrode active material composition, The method for manufacturing a positive electrode according to claim 14, wherein the transfer is carried out at a temperature of -30°C or higher and 15°C or lower.

Description

This application claims priority under Korean Patent Application No. 10-2023-0070277 dated May 31, 2023, and all content disclosed in the said Korean Patent Application is incorporated herein by reference. This invention relates to a method for producing a positive electrode slurry composition and a method for producing a positive electrode. As the development and demand for mobile device technologies increase, the demand for rechargeable batteries as an energy source is rapidly rising. Among these rechargeable batteries, lithium-ion batteries, which possess high energy density and voltage, long cycle life, and low self-discharge rates, have been commercialized and are widely used. Lithium transition metal composite oxides are used as the positive electrode active material for lithium secondary batteries, and among them, lithium cobalt composite metal oxides such as LiCoO₂ are mainly used because they have a high operating voltage and excellent capacity characteristics. However, LiCoO₂ has poor thermal properties due to the destabilization of its crystal structure by delithiation. Furthermore, because LiCoO₂ is expensive, there are limitations to its large-scale use as a power source in fields such as electric vehicles. As alternatives to the aforementioned LiCoO2 , lithium manganese composite metal oxides ( such as LiMnO2 or LiMn2O4 ), lithium iron phosphate compounds (such as LiFePO4 ), and lithium nickel composite metal oxides (such as LiNiO2 ) have been developed. Among these, research and development on lithium nickel composite metal oxides, which have a high reversible capacity of approximately 200 mAh/g and facilitate the realization of high-capacity batteries, are being pursued more actively. However, LiNiO2 has inferior thermal stability compared to LiCoO2 , and if an internal short circuit occurs due to external pressure while charged, the positive electrode active material itself decomposes, causing the battery to rupture and ignite. Therefore, as a method to maintain the excellent reversible capacity of LiNiO2 while improving its low thermal stability, lithium transition metal oxides in which some of the Ni is replaced with Co, Mn, and Al have been developed. Lithium nickel composite metal oxides and lithium transition metal oxides containing a large amount of nickel may leave a relatively large amount of lithium oxide as an impurity during the manufacturing process. This impurity can be converted into LiOH and Li₂CO₃ , which can cause gelation during the manufacturing process of the cathode slurry and during the process of manufacturing the cathode using the manufactured cathode slurry. When the cathode slurry gels, its viscosity increases, which can cause problems in the cathode manufacturing process, and consequently, significant costs and efforts are required to control the process. Furthermore, increasing the solid content of the positive electrode slurry has effects such as increased productivity, improved electrode drying efficiency, and improved binder migration. However, a higher solid content leads to higher viscosity, and the viscosity of the manufactured positive electrode slurry increases rapidly with storage time. Such a rapid increase in viscosity can lead to quality problems with the positive electrodes manufactured using this slurry, and the slurry itself may become difficult to use in the manufacture of positive electrodes. Therefore, there is a need to develop a method that can suppress the increase in viscosity over time after the production of a positive electrode slurry with a high solid content. Japanese Patent Publication No. 2007-141649 The present invention will be described in more detail below to aid in understanding the present invention. The terms and words used in this specification and in the claims should not be interpreted in a manner limited to their ordinary or dictionary meanings. Rather, they should be interpreted in a manner consistent with the technical spirit of the present invention, in accordance with the principle that inventors may appropriately define the concepts of terms to best describe their invention. In this specification, terms such as “include,” “equip,” or “have” are intended to specify the presence of implemented features, figures, steps, components, or combinations thereof, and should be understood not to preemptively exclude the existence or possibility of adding one or more other features, figures, steps, components, or combinations thereof. In this specification, the content of each element in the lithium complex transition metal compound may be measured by ICP (Inductive Coupled Plasma) analysis using an inductively coupled plasma emission spectrometer (ICP-OES; PerkinElmer, Optima 8000DV). Method for producing a positive electrode slurry composition The method for producing a positive electrode slurry composition according to the present invention will be described below. The present invention provides a method for producing a positiv