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JP-7856787-B2 - Electrodes for all-solid-state batteries

JP7856787B2JP 7856787 B2JP7856787 B2JP 7856787B2JP-7856787-B2

Inventors

  • ジョンギル・キム
  • ヘジン・クォン
  • ソヒ・キム
  • キ・テ・キム
  • テゴン・キム
  • ミョンス・キム

Assignees

  • エルジー エナジー ソリューション リミテッド

Dates

Publication Date
20260511
Application Date
20230829
Priority Date
20220901

Claims (13)

  1. An electrode for an all-solid-state battery comprising granules coated with a sulfide-based solid electrolyte, The granules comprise an active material, a conductive material, and a binder. The conductive material is carbon black having an average particle size of 120 nm to 200 nm. The carbon black aggregates to form secondary particles. The secondary particles have a particle size of 600 nm to 1,100 nm and are electrodes for all-solid-state batteries.
  2. The electrode for an all-solid-state battery according to claim 1, characterized in that the carbon black has a BET specific surface area of 15 m² /g to 35 m² /g.
  3. The electrode for an all-solid-state battery according to claim 1, characterized in that the carbon black has a DBP absorption rate of 70 ml/100 g to 100 ml/100 g.
  4. The electrode for an all-solid-state battery according to claim 1, characterized in that the granules are spherical particles having a diameter of 30 μm to 150 μm.
  5. The electrode for an all-solid-state battery according to claim 1, characterized in that the granules have a porosity of 20% to 40%.
  6. The electrode for the all-solid-state battery is the positive electrode. The active materials include LiCoO 2 , LiNiO 2 , LiMnO 2 , Li 2 MnO 3 , LiMn 2 O 4 , Li( Nia Co b Mn c )O 2 (0<a<1, 0<b<1, 0<c<1, a+b+c=1), LiNi 1-y Co y O 2 (0<y<1), LiCo 1-y Mny O 2 (0<y<1), LiNi 1-y Mny O 2 (0<y<1), Li( Nia Co b Mn c )O 4 (0<a<2, 0<b<2, 0<c<2, a+b+c=2), LiMn 2-z Ni z O The electrode for an all-solid-state battery according to claim 1, characterized in that it is selected from the group consisting of 4 (0 < z < 2), LiMn 2-z Co z O 4 (0 < z < 2), and combinations thereof.
  7. The aforementioned binder is an organic binder. The electrode for an all-solid-state battery according to claim 1, characterized in that the organic binder is selected from the group consisting of polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinyl alcohol, starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, polyimide, polyamide-imide, polyethylene, polypropylene, ethylene-propylene-diene monomer (EPDM), sulfonated EPDM, styrene-butylene rubber, and fluororubber.
  8. The electrode for an all-solid-state battery according to claim 1, characterized in that the granules contain 85% to 99.8% by weight of active material, 0.1% to 10% by weight of binder, and 0.1% to 10% by weight of conductive material.
  9. The electrode for an all-solid-state battery according to claim 1, characterized in that the electrode active material layer containing granules coated with a sulfide-based solid electrolyte has a thickness of 100 μm to 300 μm.
  10. The electrode for an all-solid-state battery according to claim 1, characterized in that the electrode active material layer containing granules coated with a sulfide-based solid electrolyte contains 10% to 30% by weight of the sulfide-based solid electrolyte, based on the content of the granules.
  11. The electrode for an all-solid-state battery according to claim 1, characterized in that when the granules are divided into first, second, and third regions in order from the center to the outside of the granules by dividing the inner diameter of the granules into equal intervals, the content of the conductive material in the granules increases in the order of first, second, and third regions.
  12. The electrode for an all-solid-state battery according to claim 11 , characterized in that the granules have an R value of 5 or less, and the R value is defined by the following formula 1: [Formula 1] Here, r A is the conductive material content (%) in the first region, r B is the conductive material content (%) in the second region, and r C is the conductive material content (%) in the third region, with the conductive material content in each region being based on the total conductive material content of the granules.
  13. A solid-state battery comprising the electrode for solid-state batteries described in claim 1 as either the positive or negative electrode.

Description

This application relates to an electrode for an all-solid-state battery. Specifically, it relates to a positive electrode for an all-solid-state battery comprising granules coated with a sulfide-based solid electrolyte. This application claims priority under Korean Patent Application No. 10-2022-0110540 dated September 1, 2022, and incorporates all the contents disclosed in the said Korean Patent Application as part of this Specification. From the perspectives of battery capacity, safety, output, scaling up, and miniaturization, various types of batteries that can overcome the limitations of lithium-ion secondary batteries are currently being researched. Typically, research is continuously being conducted in academia and industry on metal-air batteries, which have a significantly larger theoretical capacity compared to lithium-ion batteries; all-solid-state batteries, which pose no risk of explosion in terms of safety; supercapacitors, which offer superior power output; NaS batteries or RFBs (redox flow batteries), which are being developed for larger sizes; and thin-film batteries, which are being developed for ultra-miniaturization. Among these, all-solid-state batteries refer to batteries in which the liquid electrolyte used in conventional lithium-ion secondary batteries is replaced with a solid. Because they do not use flammable solvents within the battery, they completely eliminate the risk of ignition or explosion due to the decomposition reaction of conventional electrolytes, thus significantly improving safety. Furthermore, because lithium metal or lithium alloy can be used as the negative electrode material, there is the advantage of dramatically improving the energy density relative to the battery's mass and volume. In particular, among the solid electrolytes of all-solid-state batteries, inorganic solid electrolytes are divided into sulfide-based and oxide-based types. Currently, the most technologically advanced solid electrolyte is the sulfide-based solid electrolyte, and materials with ionic conductivity close to that of organic electrolytes have been developed. Sulfide-based solid electrolytes have high ionic conductivity of 10⁻³ to 10⁻² S/cm among solid electrolytes, and their ductility and good contact with interfaces are advantageous for improving resistance. However, they are sensitive to moisture, generating H₂S gas when in contact with water, so it is necessary to create a very dry environment during manufacturing. Furthermore, it is necessary to improve the aggregation of the active material and the solid electrolyte, and high-density electrodes are required by reducing the porosity. Therefore, in order to solve the problems faced in this technical field, the inventors have continuously researched electrodes for all-solid-state batteries and have completed the present invention. Korean Published Patent Publication No. 10-2016-0146737 This is an SEM image (1,000x magnification) of the granules from Manufacturing Example 1, produced according to Experimental Example 1.This is an SEM image (5,000x magnification) of the granules from Manufacturing Example 1, produced according to Experimental Example 1.This is an SEM image (1,000x magnification) of the granules from comparative manufacturing example 1, based on experimental example 1.This is an SEM image (5,000x magnification) of the granules from comparative manufacturing example 1, based on experimental example 1.This diagram schematically shows the locations of the first region (A), the second region (B), and the third region (C) in the granule. All embodiments provided in accordance with the present invention can be achieved by the following description. The following description should be understood as illustrating preferred embodiments of the present invention, and it should be understood that the invention is not necessarily limited thereto. Unless otherwise specified, the measurement conditions and methods for any physical properties described herein shall be measured according to the measurement conditions and methods commonly used by ordinary artisans in that field. In one aspect of the present invention, an electrode for an all-solid-state battery is provided, comprising granules coated with a sulfide-based solid electrolyte. The granules are spherical particles comprising an active material, a conductive material, and a binder. Here, "spherical" does not mean perfectly spherical in the strict sense, but is used as a general concept encompassing particles with a round shape. The active material, in powder form, is bound together with the conductive material, which is either primary or secondary particles, by a binder solution to grow into particles having a specific range of specifications. The conductive material may be applied as primary particles, as secondary particles, or in a mixed form of primary and secondary particles. According to one embodiment of the present invention, the granules are spherical particles having a d