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CN-122025730-A - Solid-state battery, preparation method thereof, solid electrolyte membrane, electrolyte pole piece and power utilization device

CN122025730ACN 122025730 ACN122025730 ACN 122025730ACN-122025730-A

Abstract

The application relates to a solid-state battery, a preparation method thereof, a solid electrolyte membrane, an electrolyte pole piece and an electric device. The solid-state battery comprises a first electrode layer, a solid electrolyte layer and a second electrode layer which are sequentially stacked, wherein the solid electrolyte layer comprises a first electrolyte layer, the first electrolyte layer is arranged on one side, close to the first electrode layer, of the solid electrolyte layer, the first electrolyte layer comprises sulfide solid electrolyte and a first binder, and the first binder comprises an amphiphilic binder. The solid-state battery has improved cycle performance.

Inventors

  • WU KAI
  • Ling Yuexia

Assignees

  • 宁德时代新能源科技股份有限公司

Dates

Publication Date
20260512
Application Date
20241108

Claims (20)

  1. 1. The solid-state battery is characterized by comprising a first electrode layer, a solid electrolyte layer and a second electrode layer which are sequentially stacked, wherein the solid electrolyte layer comprises a first electrolyte layer, and the first electrolyte layer is positioned on one side, close to the first electrode layer, of the solid electrolyte layer; wherein the first electrolyte layer comprises a sulfide solid electrolyte and a first binder, the first binder comprises an amphiphilic binder, and the amphiphilic binder comprises a hydrophilic group and a lipophilic group.
  2. 2. The solid-state battery according to claim 1, wherein the contact angle value of the amphiphilic binder is 20-90 degrees, optionally 30-90 degrees, and the contact angle value is the water contact angle value of a film material composed of the amphiphilic binder, and the test temperature is 23+ -2 ℃.
  3. 3. The solid state battery of claim 2, wherein the contact angle value of the amphiphilic binder is 45 ° -90 °, optionally 60 ° -90 °, and the test temperature is 23±2°.
  4. 4. A solid state battery according to any of claims 1-3, wherein the amphiphilic binder satisfies one or more of the following characteristics: The hydrophilic group comprises one or more of a chlorine atom, an ether bond, a carboxyl group, -C (=O) -O-and an amide group; The lipophilic group comprises a C 1-8 alkyl group.
  5. 5. The solid state battery of claim 4, wherein the lipophilic group comprises one or more of methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, and octyl.
  6. 6. The solid state battery of any of claims 1-5, wherein the amphiphilic binder comprises a carbon backbone and pendant groups grafted to the carbon backbone, the pendant groups comprising the hydrophilic groups and the lipophilic groups.
  7. 7. The solid state battery of any of claims 1-6, wherein the amphiphilic binder comprises an amphiphilic rubber.
  8. 8. The solid state battery of claim 7, wherein the contact angle value of the amphiphilic rubber is 20 ° -90 °, optionally 30 ° -90 °, further optionally 60 ° -90 °; the contact angle value is the water contact angle value of the film material composed of the amphiphilic adhesive, and the test temperature is 23+/-2 ℃.
  9. 9. The solid state battery of claim 7 or 8, wherein the amphiphilic rubber satisfies one or more of the following characteristics: The elastic deformation of the amphiphilic rubber at 45 ℃ is recorded as delta, and delta is more than or equal to 200%; the elastic modulus of the amphiphilic rubber at 30 ℃ is marked as E, and E is less than or equal to 100MPa.
  10. 10. The solid state battery of claim 9, wherein the amphiphilic rubber satisfies one or more of the following characteristics: Elastic deformation of the amphiphilic rubber at 45 ℃ is more than or equal to 450% and less than or equal to 600%; the elastic modulus of the amphiphilic rubber at 30 ℃ meets E which is more than or equal to 50MPa and less than or equal to 85MPa.
  11. 11. The solid-state battery according to any one of claims 7 to 10, wherein the amphiphilic rubber comprises an amphiphilic acrylic rubber.
  12. 12. The solid state battery of claim 11, wherein the amphiphilic acrylate rubber comprises one or more of a chloro acrylate rubber, an active chloro acrylate rubber, an epoxy acrylate rubber, a carboxyl acrylate rubber, a double bond acrylate rubber, a double cross-linked acrylate rubber, and an ethylene methyl acrylate rubber.
  13. 13. The solid state battery of any of claims 1-12, wherein the first electrolyte layer satisfies one or more of the following characteristics: The weight percentage of the amphiphilic binder in the first electrolyte layer is 0.5-15 wt%; the weight ratio of the amphiphilic adhesive in the first adhesive is more than or equal to 10%, and is optionally 10% -100%; The amphiphilic adhesive comprises amphiphilic rubber, wherein the weight percentage of the amphiphilic rubber in the first electrolyte layer is 0.5-15 wt%; the amphiphilic adhesive comprises amphiphilic rubber, wherein the weight ratio of the amphiphilic rubber in the first adhesive is more than or equal to 10%, and is optionally 10% -100%; the first binder further comprises one or more of nitrile rubber, styrene-butadiene rubber, hydrogenated nitrile rubber, natural rubber, polyvinylidene fluoride, etherified cellulose, polymethyl methacrylate, polyethylene oxide and methyl vinyl silicone rubber; The thickness of the first electrolyte layer is 10-70 mu m.
  14. 14. The solid state battery of claim 13, wherein the first electrolyte layer satisfies one or more of the following characteristics: the weight percentage of the amphiphilic binder in the first electrolyte layer is 1-15 wt%; the weight ratio of the amphiphilic adhesive in the first adhesive is 30% -100%; The amphiphilic adhesive comprises amphiphilic rubber, wherein the weight percentage of the amphiphilic rubber in the first electrolyte layer is 1-15 wt%; The amphiphilic adhesive comprises amphiphilic rubber, and the weight ratio of the amphiphilic rubber in the first adhesive is 30-100 wt%; The thickness of the first electrolyte layer is 20-50 mu m.
  15. 15. The solid state battery of any of claims 1-14, wherein the first electrolyte layer satisfies one or more of the following characteristics: In the first electrolyte layer, the weight ratio of the amphiphilic binder to the sulfide solid electrolyte is (2-20) 100; in the first electrolyte layer, the amphiphilic adhesive comprises an amphiphilic rubber, and the weight ratio of the amphiphilic rubber to the sulfide solid electrolyte is (2-20): 100.
  16. 16. The solid state battery of any of claims 1-15, wherein the first electrolyte layer satisfies one or more of the following characteristics: in the first electrolyte layer, the weight ratio of the amphiphilic binder to the sulfide solid electrolyte is (2-18) 100; In the first electrolyte layer, the amphiphilic adhesive comprises an amphiphilic rubber, and the weight ratio of the amphiphilic rubber to the sulfide solid electrolyte is (2-18): 100.
  17. 17. The solid state battery of any one of claims 1-16, wherein the sulfide solid electrolyte comprises one or more of LGPS-type sulfide electrolyte, silver germanium sulfide ore-type sulfide electrolyte, lithium sulfide phosphorus pentasulfide complex-type sulfide electrolyte, and thio-LISICON sulfide electrolyte.
  18. 18. The solid state battery of claim 17, wherein the sulfide solid electrolyte comprises L i6- x PS 5-x Cl 1+x , wherein 0≤x≤0.9.
  19. 19. The solid state battery of any one of claims 1-18, wherein the solid electrolyte layer further comprises a second electrolyte layer, the second electrolyte layer being located between the second electrode layer and the first electrolyte layer; wherein the second electrolyte layer comprises a solid electrolyte and optionally a second binder.
  20. 20. The solid state battery of claim 19, wherein the weight percent of the amphiphilic binder in the second electrolyte layer is denoted as f12 and the weight percent of the amphiphilic binder in the first electrolyte layer is denoted as f11; the second electrolyte layer satisfies one or more of the following characteristics: 0≤f12<f11; The weight percentage f12 of the amphiphilic binder in the second electrolyte layer is 0-5 wt%.

Description

Solid-state battery, preparation method thereof, solid electrolyte membrane, electrolyte pole piece and power utilization device Technical Field The application relates to the technical field of solid-state batteries, and further relates to a solid-state battery, a preparation method thereof, a solid electrolyte membrane, an electrolyte pole piece and an electric device. Background The statements herein merely provide background information related to the present disclosure and may not necessarily constitute prior art. The solid-state battery introduces nonflammable solid electrolyte to replace organic electrolyte in the traditional liquid secondary battery, so that the safety of the battery is greatly improved. However, in the solid-state battery, the problems of poor interfacial contact and interfacial side reactions are one of the pain points that limit the performance thereof, resulting in the battery having less than ideal cycle performance. Disclosure of Invention In view of the above, the present application provides a solid state battery, a method of manufacturing the same, a solid electrolyte membrane, an electrolyte sheet, and an electric device according to various embodiments and various examples of the present application. The solid-state battery has improved cycle performance. In a first aspect, the application provides a solid-state battery, which comprises a first electrode layer, a solid electrolyte layer and a second electrode layer which are sequentially stacked, wherein the solid electrolyte layer comprises a first electrolyte layer, and the first electrolyte layer is positioned on one side, close to the first electrode layer, of the solid electrolyte layer; wherein the first electrolyte layer comprises a sulfide solid electrolyte and a first binder, the first binder comprising an amphiphilic binder. In some embodiments, the amphiphilic binder includes a hydrophilic group and a lipophilic group. The solid-state battery is provided with the first electrolyte layer including the sulfide solid electrolyte and the binder (which may be referred to as a first binder) on the side of the solid electrolyte layer near the first electrode layer, and by introducing the amphiphilic binder having both the hydrophilic group and the lipophilic group into the first electrolyte layer, the bonding between the binder and the sulfide solid electrolyte can be enhanced by utilizing the van der Waals force between the hydrophilic group and the sulfide, the presence of the lipophilic group is favorable for inhibiting the agglomeration of the binder, the sulfide solid electrolyte and the amphiphilic binder can be promoted to be uniformly dispersed in the first electrolyte layer, the transmission of active ions in the solid electrolyte layer can be promoted, and thus the cycle performance of the solid-state battery can be improved. On the other hand, the improvement of the dispersion uniformity of the sulfide solid electrolyte and the amphiphilic binder in the first electrolyte layer is beneficial to improving the contact network between sulfide solid electrolytes, improving the binding force, improving the stability and mechanical strength of the first electrolyte layer and the solid electrolyte layer, promoting the transmission of active ions, and further improving the cycle performance and discharge capacity of the battery. In another aspect, the improvement of the dispersion uniformity of the sulfide solid electrolyte and the amphiphilic binder in the first electrolyte layer is beneficial to improving the adhesive strength of the first electrolyte layer on the first electrode layer, reducing the interface stability and interface impedance between the solid electrolyte layer and the first electrode layer, and further improving the cycle stability and discharge capacity of the battery. Further, the first electrolyte layer may be formed by coating and drying a slurry including a sulfide solid electrolyte, a binder, and an organic solvent. When the organic solvent is selected to be a low-polarity or nonpolar solvent, the sulfide solid electrolyte is liable to be insufficiently uniformly dispersed in the slurry due to the high reactivity of the sulfide solid electrolyte. By introducing an amphiphilic binder having both hydrophilic groups and lipophilic groups into the first electrolyte layer, the dispersion uniformity of the sulfide solid electrolyte in the slurry can be improved by utilizing the good compatibility of the lipophilic groups to the solvent and the van der Waals force between the hydrophilic groups and the sulfide, so that the dispersion uniformity of the sulfide solid electrolyte in the first electrolyte layer can be improved, the cycle performance of the solid battery can be further improved, the film forming strength of the first electrolyte layer and the adhesive strength of the first electrolyte layer on the film forming substrate can be further improved, and the film stripping risk can be remark