Method of manufacturing positive electrode for solid-state battery, method of manufacturing solid-state battery, and positive electrode slurry

Abstract

The invention relates to a METHOD OF MANUFACTURING a POSITIVE ELECTRODE FOR a SOLID-STATE BATTERY, METHOD OF MANUFACTURING the SOLID-STATE BATTERY, AND POSITIVE ELECTRODE SLURRY. Provided is a method of manufacturing a positive electrode for a solid-state battery, the method including: a step of mixing a positive electrode active material, a sulfide solid electrolyte, a binder, and a solvent with each other to prepare a positive electrode slurry; a step of applying the prepared positive electrode slurry to a surface of a solid electrolyte layer of the solid-state battery or a substrate of the positive electrode; and a step of drying the applied positive electrode slurry. In this method, the solvent is butyl butyrate, and the binder is a copolymer containing a vinylidene fluoride (VDF) monomer unit and a hexafluoropropylene (HFP) monomer unit, in which a molar ratio of the HFP monomer unit to a total amount of the VDF monomer unit and the HFP monomer unit is 10% to 20%.

Description

technical field [0001] The invention relates to a method for manufacturing a positive electrode for a solid battery. Background technique [0002] A solid-state battery is known as one type of battery excellent in safety. A solid battery includes electrodes containing an active material and the like, and a solid electrolyte layer serving as a separator layer between the electrodes. Such an electrode and a solid electrolyte layer can be easily produced using a slurry obtained by dispersing an active material, a solid electrolyte, and the like in a solvent. For example, as described in Japanese Unexamined Patent Publication No. 2013-118143, by mixing an electrode active material, a sulfide-based solid electrolyte, a binder, and a solvent to prepare a slurry, coating the slurry, and then drying it process, a desired electrode layer can be obtained. As the binder in this case, polyvinylidene fluoride disclosed in JP-A-2013-222530 and JP-A-2012-138346, or a combination of viny...

AI Technical Summary

Problems solved by technology

However, in conventional combinations of binders and solvents, battery performance may deteriorate after rapid drying

That is, due to rapid drying, the binder becomes uneven in the electrode, and as a result, there is a problem that the resistance increases and the battery output decreases

[0004] In addition, the solvents used in the past sometimes react with the sulfide-based solid electrolyte, resulting in a decrease in the lithium ion conductivity of the sulfide-based solid electrolyte.

[0005] In addition, when a three-component copolymer of VDF, HFP and tetrafluoroethylene (TFE) or polyvinylidene fluoride is used as a binder, the adhesive force between the current collector and the electrode layer is insufficient, In the manufacture of solid batteries, peeling and cracking sometimes occur in electrodes

[0006] As described above, in the past, when manufacturing the positive electrode of a solid battery, it was not possible to simultaneously suppress the deterioration of the sulfide-based solid electrolyte, ensure sufficient adhesion between the current collector and the electrode layer, and suppress the battery output caused by rapid drying. Decline

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