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CN-122029619-A - Solid electrolyte sheet

CN122029619ACN 122029619 ACN122029619 ACN 122029619ACN-122029619-A

Abstract

The solid electrolyte sheet contains a solid electrolyte and a binder. The thickness of the solid electrolyte sheet is 90 μm or less. The content of the binder in the solid electrolyte sheet is more than 1 mass%. The solid electrolyte contains a crystal phase having a sulfur silver germanium ore type crystal structure. The solid electrolyte sheet does not contain a porous support. The solid electrolyte sheet is self-supporting. The content of the binder is preferably 20 mass% or less. The solid electrolyte sheet is also preferably 2.0N/mm 2 or more in tensile strength.

Inventors

  • Tsukimoto Chong Si
  • Kobayashi Angui
  • OGATA YOICHIRO

Assignees

  • 三井金属株式会社

Dates

Publication Date
20260512
Application Date
20241023
Priority Date
20231027

Claims (7)

  1. 1. A solid electrolyte sheet comprising a solid electrolyte and a binder, The solid electrolyte sheet has a thickness of 90 [ mu ] m or less, The content of the binder is more than 1 mass%, The solid electrolyte contains a crystal phase having a sulfur silver germanium ore type crystal structure, The solid electrolyte sheet does not contain a porous support and is self-supporting.
  2. 2. The solid electrolyte sheet according to claim 1, wherein the content of the binder is 20 mass% or less.
  3. 3. The solid electrolyte sheet according to claim 1 or 2, which has a tensile strength of 2.0N/mm 2 or more.
  4. 4. The solid electrolyte sheet according to claim 1 or 2, which has a density of 1.0g/cm 3 or more and 2.0g/cm 3 or less.
  5. 5. The solid electrolyte sheet according to claim 1 or 2, wherein the young's modulus of the solid electrolyte is 30GPa or less.
  6. 6. The solid electrolyte sheet according to claim 1 or 2, wherein a volume cumulative particle diameter D 50 of the solid electrolyte at a cumulative volume of 50% by volume based on a laser diffraction scattering particle size distribution measurement is 0.1 μm or more and 20 μm or less.
  7. 7. The solid electrolyte sheet according to claim 1 or 2, wherein the binder is a fluorine-containing polymer compound.

Description

Solid electrolyte sheet Technical Field The present invention relates to a solid electrolyte sheet. Background In recent years, secondary batteries have been attracting attention as a countermeasure against global warming by reducing CO 2. Among them, solid-state batteries are expected to be put into practical use as batteries having both safety and high energy density. In the case of manufacturing a solid-state battery, a solid electrolyte sheet mainly containing powder of a solid electrolyte is sometimes used as one of the components constituting the solid-state battery. For example, patent document 1 describes a solid electrolyte sheet in which a solid electrolyte powder is supported by a support made of a nonwoven fabric, the content of a binder is less than 0.5 mass%, and the thickness is 100 μm or less. However, in the case where the solid electrolyte sheet has a support, the adhesion of particles of the solid electrolyte to each other may be hindered by the support, and it may be difficult to improve the conductivity. In addition, the current may concentrate at a specific portion in the solid electrolyte sheet, which may cause degradation of the battery. Therefore, a solid electrolyte sheet having no support is also proposed. For example, non-patent document 1 describes that a slurry obtained by dispersing a solid electrolyte powder represented by the composition formula Li 6PS5 Cl in a solvent together with a binder is applied to a polytetrafluoroethylene film, and the thus obtained coating film is dried and compacted at 300MPa to produce a solid electrolyte sheet having a thickness of 90 μm to 120 μm. Prior art literature Patent literature Patent document 1 Japanese patent application laid-open No. 2018-129307 Non-patent literature Non-patent document 1:J.Energy Storage,66 (2023) 107480 Disclosure of Invention However, the solid electrolyte sheet having no support tends to have a large thickness in order to secure self-supporting properties. When the thickness of the solid electrolyte sheet increases, the electrical resistance thereof increases, and as a result, the electrical conductivity may decrease. Accordingly, an object of the present invention is to provide a solid electrolyte sheet in which a decrease in conductivity is suppressed. The present invention provides a solid electrolyte sheet comprising a solid electrolyte and a binder, wherein the thickness of the solid electrolyte sheet is 90 [ mu ] m or less, the content of the binder is more than 1 mass%, the solid electrolyte comprises a crystal phase having a sulfur silver germanium ore type crystal structure, and the solid electrolyte sheet does not comprise a porous support and has self-supporting property. Detailed Description The present invention relates to a solid electrolyte sheet. The solid electrolyte sheet of the present invention comprises a sheet member containing a solid electrolyte. In the present specification, a sheet means a member having a first main surface and a second main surface located on the opposite side thereof, and having a minimum thickness (for example, a thickness of 1 or less per 100 minutes relative to the longitudinal dimension and the transverse dimension) which is a distance between the two main surfaces. One of the characteristics of the solid electrolyte sheet of the present invention is that the solid electrolyte sheet is self-supporting although it does not contain a porous support. In the present specification, self-supporting means rigidity of the solid electrolyte sheet, and self-supporting means that the solid electrolyte sheet itself can be used to maintain the sheet form even if a support member that is a separate member from the solid electrolyte sheet is not used. For example, a test piece obtained by cutting the solid electrolyte sheet of the present invention into a square of 1cm×1cm is prepared, and when the test piece is held at adjacent corners (for example, in a rectangular region of 3mm×3 mm) and suspended, the solid electrolyte sheet can be said to have self-supporting properties when the test piece is not broken by its own weight. The porous support may be any known in the art. Examples thereof include woven and nonwoven fabrics made of natural fibers or synthetic fibers, porous films made of synthetic resins, and glass fiber fabrics. In order to make the solid electrolyte sheet of the present invention self-supporting, one of the characteristics of the solid electrolyte sheet is its composition. Specifically, the solid electrolyte sheet of the present invention suitably contains a solid electrolyte and a binder, and the content of the binder relative to the solid electrolyte sheet is preferably more than 1 mass%. By containing the binder at such a content, the solid electrolyte sheet of the present invention can maintain its own form even if it does not contain a porous support. The content of the binder may be, for example, 2 mass% or more, 3 mass% or more, 4 mass% or more, or 5 ma