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JP-7856279-B2 - Composite particles for electrodes and method for manufacturing the same

JP7856279B2JP 7856279 B2JP7856279 B2JP 7856279B2JP-7856279-B2

Inventors

  • 仲村 英也
  • 綿野 哲

Assignees

  • 公立大学法人大阪

Dates

Publication Date
20260511
Application Date
20210728

Claims (20)

  1. Composite particles for electrodes comprising a crystalline sulfur phase and carbon particles dispersed within the crystalline phase, The volume-based average particle diameter (D50) of the carbon particles is in the range of 1 to 999 nm. The carbon particles have amorphous sulfur on the surface and/or inside the carbon particles. The composite particles for electrodes have a volume-based average particle diameter (D50) in the range of 1 to 1000 μm . Composite particles for electrodes , wherein the carbon particles are porous carbon particles, and amorphous sulfur is contained within the pores of the carbon particles .
  2. The electrode composite particle according to claim 1, wherein the composite particle further comprises solid electrolyte particles having a volume-based average particle diameter (D50) in the range of 0.01 to 50 μm.
  3. The composite particle for electrodes according to claim 1 or 2, wherein the nitrogen adsorption amount of the composite particle is 50% or less of the nitrogen adsorption amount of the carbon particles contained in the composite particle.
  4. The composite particle for electrodes according to any one of claims 1 to 3, wherein the carbon particles have a maximum nitrogen adsorption capacity of 1000 ml (STP)/g or more.
  5. The electrode composite particle according to any one of claims 1 to 4, wherein the carbon particles are at least one selected from acetylene black, furnace black, natural graphite, or artificial graphite.
  6. The electrode composite particle according to claim 2 or any one of claims 3 to 5 that directly or indirectly references claim 2, wherein the solid electrolyte is a sulfide-based solid electrolyte.
  7. The solid electrolyte is Li 3 PS 4 , Li 2 SP 2 S 5 , Li 2 SP 2 S 5 -LiI, Li 2 SP 2 S 5 -LiCl, Li 2 SP 2 S 5 -LiI-LiBr, Li 2 SP 2 S 5 -Li 2 O, Li 2 SP 2 S 5 -Li 2 O-LiI, Li 2 S-SiS 2 , Li 2 S-SiS 2 -LiI, Li 2 S-SiS 2 -LiBr, Li 2 S-SiS 2 -LiCl, Li 2 S-SiS 2 -B 2 S 3 -LiI, Li 2 S-SiS 2 -P 2 S 5 -LiI, Li 2 SB 2 S 3 , Li 2 SP 2 S 5 -GeS 2 , LiI-Li 2 SP 2 O 5 , LiI-Li 3 PO 4 -P 2 Composite electrode particles according to claim 2 or any one of claims 3 to 6 that directly or indirectly reference claim 2, wherein the composite particle is at least one selected from S 5, Li 10 GeP 2 S 12, Li 7 P 3 S 11, Li 3.25 P 0.75 S 4, or Li 7-x PS 6-x Y x ( wherein x is between 0 and 1.8 and Y is a halogen).
  8. The composite particle for electrodes according to any one of claims 1 to 7 , wherein the mass ratio of the crystalline sulfur phase to the carbon particles is in the range of sulfur:carbon particles = 1.0:0.1 to 1.0.
  9. Composite electrode particles according to claim 2 or any one of claims 3 to 8 that directly or indirectly references claim 2, wherein the mass ratio of the sulfur and carbon particles to the solid electrolyte particles is in the range of sulfur + carbon particles:solid electrolyte = 1.0:0.1 to 1.0.
  10. The electrode composite particle according to any one of claims 1 to 9 , wherein the BET specific surface area of the composite particle as determined by the nitrogen adsorption isotherm is 200 m² /g or less.
  11. The electrode composite particle according to any one of claims 1 to 10 , wherein the BET specific surface area of the composite particle as determined by the nitrogen adsorption isotherm is 10 m² /g or less.
  12. Composite particle for electrodes according to any one of claims 1 to 11, wherein the particle diameter (D10) at which the cumulative frequency of the volume-based particle diameter distribution of the composite particle reaches 10% is in the range of 0.5 to 50 μm, the volume-based average particle diameter (D50) is in the range of 1 to 100 μm, and the particle diameter (D90) at which the cumulative frequency of the volume-based particle diameter distribution reaches 90% is in the range of 5 to 500 μm.
  13. The composite particle for electrodes according to claim 12, wherein the particle diameter (D10) at which the cumulative frequency of the volume-based particle diameter distribution of the composite particle reaches 10% is in the range of 10 to 20 μm, the volume-based average particle diameter (D50) is in the range of 50 to 100 μm, and the particle diameter (D90) at which the cumulative frequency of the volume-based particle diameter distribution reaches 90% is in the range of 100 to 500 μm.
  14. An electrode active material comprising electrode composite particles according to any one of claims 1 to 13 .
  15. An electrode comprising electrode composite particles according to any one of claims 1 to 13 or an electrode active material according to claim 14 .
  16. A secondary battery comprising the electrode described in claim 15 .
  17. The secondary battery according to claim 16 , wherein the secondary battery is an all-solid-state secondary battery.
  18. A method for producing electrode composite particles according to any one of claims 1 to 13 , comprising the step of heating and kneading a sulfur composition and carbon particles in a twin-screw fusion kneader.
  19. The method for producing electrode composite particles according to claim 18 , wherein the temperature during the heating and kneading is in the range of 120°C to 200°C.
  20. A method for producing electrode composite particles according to claim 2 or claim 18 or 19 , which directly or indirectly references claim 2, further comprising the step of adding and mixing solid electrolyte particles after heating and kneading.

Description

This invention relates to electrode composite particles, electrode active materials, electrodes, secondary batteries, and methods for producing electrode composite particles. More specifically, it relates to electrode composite particles comprising a crystalline sulfur phase and carbon particles dispersed in the crystalline phase. In recent years, the demand for lithium-ion secondary batteries for storing electricity has been increasing in vehicles such as electric vehicles (EVs) and hybrid vehicles, as well as in power generation equipment such as solar cells and wind turbines. Furthermore, from the perspective of ensuring safety, all-solid-state batteries, which use a solid electrolyte instead of a liquid electrolyte layer, are being actively researched. These lithium-ion secondary batteries and all-solid-state batteries are required to be even more high-performance. Many all-solid-state batteries under development use metal oxides as the positive electrode active material, but considering the energy storage capacity required for EVs and other applications, there is a need to use active material materials with a larger theoretical capacity. Among these, the use of sulfur as an active material is attracting attention. Sulfur has a large theoretical capacity (1672 mAh g⁻¹ ) and is therefore expected to be a promising active material for next-generation all-solid-state batteries. However, because sulfur has low electronic and ionic conductivity, it cannot be used as an electrode active material on its own. Attempts have been made to utilize sulfur, and for example, Japanese Patent Publication No. 2010-095390 (Patent Document 1) and Japanese Patent Publication No. 2020-161288 (Patent Document 2) disclose composites in which sulfur is deposited on carbon particles. Japanese Patent Publication No. 2010-095390Japanese Patent Publication No. 2020-161288 This is a schematic diagram of a twin-screw fusion mixer.This graph shows the results of charge-discharge tests performed on half-cells using the electrode composite particles of Example 1 or the sample of Comparative Example 1.This graph shows the results of charge-discharge tests performed on half-cells using the electrode composite particles of Examples 2 to 4.This graph shows the results of charge-discharge tests performed on half-cells using the electrode composite particles of Examples 2, 5, and 6.This graph shows the results of charge-discharge tests performed on half-cells using the electrode composite particles of Example 2, 10, or 11.This is an SEM image of the sample from Comparative Example 5.This is an SEM image of the composite particles for the electrode in Example 2.These are SEM images of the electrode composite particles from Examples 2 to 4.These are SEM images of the electrode composite particles from Examples 2, 5, and 6.This is a SEM image of sulfur.This is a SEM image of carbon particles.This is an SEM image of LPS.This graph shows the particle size distribution of the electrode composite particles from Examples 2 to 4 and the sample from Comparative Example 5.This graph shows the particle size distribution of the electrode composite particles from Examples 2, 5, and 6 and the sample from Comparative Example 5.This graph shows the particle size distribution of the electrode composite particles of Example 10 and the sample of Comparative Example 6.This graph shows the particle size distribution of the electrode composite particles of Example 11 and the sample of Comparative Example 7.This graph shows the nitrogen adsorption isotherms of the electrode composite particles from Examples 2 to 4 and the sample from Comparative Example 5.This graph shows the nitrogen adsorption isotherms of the electrode composite particles from Examples 2, 5, and 6 and the sample from Comparative Example 5.This graph shows the nitrogen adsorption isotherms of the composite particles for the electrodes in Example 6 and the samples in Comparative Examples 4 and 5.This graph shows the nitrogen adsorption isotherms of the electrode composite particles from Examples 2, 10, and 11 and the samples from Comparative Examples 5 to 7.This graph shows the results of XRD measurements of the electrode composite particles from Example 6 and the sample from Comparative Example 5.This graph shows the results of XRD measurements of the electrode composite particles from Example 6 and the sample from Comparative Example 1.This image shows the angle of repose of the composite particles for the electrode in Example 6.This image shows the angle of repose of the sample in Comparative Example 5.This is a SEM-EDX image of the electrode composite particles of Example 6.This is an SEM-EDX image of the sample from Comparative Example 5.This graph shows the results of charge-discharge tests performed on half-cells using the electrode composite particles of Example 7 or the sample of Comparative Example 1.This graph shows the results of changing the charge-discharge rate of a half-cell using t