JP-2026076281-A - Method for producing a sulfide solid electrolyte, sulfide solid electrolyte, all-solid-state battery, and method for selecting raw material compounds used in the production of a sulfide solid electrolyte.

Abstract

[Problem] To provide a method for producing a sulfide solid electrolyte that can suppress the discharge of nitrogen into the system during the manufacturing process of the sulfide solid electrolyte, a method for selecting raw material compounds used in the production of the sulfide solid electrolyte, an all-solid-state battery equipped with the sulfide solid electrolyte, a sulfide solid electrolyte with improved thermal stability, a method for producing the same, and an all-solid-state battery equipped with the sulfide solid electrolyte. [Solution] The sulfide solid electrolyte contains P, S, N, element A, element X, and element M as constituent elements and has a crystalline structure. Here, A represents at least one element selected from the group consisting of Li, Na, and K. X represents at least one element selected from the group consisting of Cl, Br, and I. M represents at least one element selected from the group consisting of Al, Ta, Si, Sc, Mg, Nb, B, Hf, C, P, Zr, and Ti. [Selection Diagram] Figure 1

Inventors

• 福嶋 晃弘
• 西井 克弥
• 佐久間 諒
• 掛谷 忠司
• 越智 龍也

Assignees

• 株式会社ＧＳユアサ

Dates

Publication Date

20260511

Application Date

20260204

Priority Date

20180830

Claims (1)

1. A sulfide solid electrolyte containing P, S, N, element A, element X, and element M as constituent elements, and having a crystalline structure. Here, A represents at least one element selected from the group consisting of Li, Na, and K. X represents at least one element selected from the group consisting of Cl, Br, and I. M represents at least one element selected from the group consisting of Al, Ta, Si, Sc, Mg, Nb, B, Hf, C, P, Zr, and Ti.

Description

This invention relates to a method for producing a sulfide solid electrolyte, a sulfide solid electrolyte, an all-solid-state battery, and a method for selecting raw material compounds used in the production of a sulfide solid electrolyte. Non-aqueous electrolyte secondary batteries, such as lithium-ion non-aqueous electrolyte secondary batteries, are widely used in electronic devices such as personal computers and communication terminals, as well as in automobiles, due to their high energy density. Generally, these non-aqueous electrolyte secondary batteries consist of an electrode body with a pair of electrically isolated electrodes, and a non-aqueous electrolyte interposed between the electrodes. They are configured to charge and discharge by transferring ions between the two electrodes. In recent years, sulfide solid electrolytes have attracted attention as non-aqueous electrolytes for non-aqueous electrolyte secondary batteries, and various studies are being conducted on them. Patent Document 1 describes the production of a sulfide solid electrolyte having the composition 75Li2S - 25P2S5 -yLi3N using Li2S , P2S5 , and Li3N as starting materials. Patent Document 2 describes the production of a sulfide solid electrolyte using a raw material composition consisting of Li₂S , P₂S₅ , LiBr, LiI, and Li₃N . Japanese Patent Publication No. 2018-041671Japanese Patent Publication No. 2015-011898Japanese Patent Publication No. 2018-156735 Figure 1 is a flowchart of the manufacturing process for a sulfide solid electrolyte in one embodiment of the present invention.Figure 2 is a schematic cross-sectional view showing an all-solid-state battery according to one embodiment of the present invention.Figure 3 shows the XRD diffraction pattern of the sulfide solid electrolyte in the example.Figure 4 shows the XRD diffraction pattern of the comparative example sulfide solid electrolyte.Figure 5 shows the DSC curves of the intermediate sulfide solid electrolytes of the examples and comparative examples after milling and before heat treatment.Figure 6 shows the DSC curves of the intermediate sulfide solid electrolytes of the examples and comparative examples after milling and before heat treatment. First, an overview of the method for producing sulfide solid electrolytes disclosed herein will be described. A method for producing a sulfide solid electrolyte according to one aspect of the present invention is a method for producing a sulfide solid electrolyte, comprising: preparing a composition containing P, S, N, element A, and element M; reacting the composition to obtain an intermediate; and heating the intermediate to obtain a sulfide solid electrolyte, wherein the composition contains a raw material compound containing N, element A, and element M. Here, A represents at least one element selected from the group consisting of Li, Na, and K. M represents at least one element selected from the group consisting of Al, Ta, Si, Sc, Mg, Nb, B, Hf, C, P, Zr, and Ti. In this invention, "composition" means a mixture obtained by mixing two or more compounds. "Raw material compound" means a specific compound that constitutes the above composition. The inventors discovered that by using a raw material compound containing at least one element A selected from the group consisting of Li, Na, and K, at least one element M selected from the group consisting of Al, Ta, Si, Sc, Mg, Nb, B, Hf, C, P, Zr, and Ti, and N, the discharge of N into the system during the manufacturing process of sulfide solid electrolytes can be suppressed, leading to the present invention. This method for producing sulfide solid electrolytes suppresses the discharge of nitrogen (N) from the system during the manufacturing process. Therefore, it becomes easier to control the N content in the sulfide solid electrolyte. While the exact reason for this is unclear, the following reasons are speculated. In the method for producing a sulfide solid electrolyte using Li3N disclosed in Patent Document 1 and Patent Document 3, the energy for generating nitrogen vacancies in Li3N is small, and N2 gas is easily generated. In contrast, in the method for producing the sulfide solid electrolyte using raw material compounds containing N, element A, and element M, the defect generation energy for N is large, and N defects are less likely to be generated during the synthesis process of the sulfide solid electrolyte, thus making it difficult to generate N2 gas. Therefore, the discharge of N into the system during the manufacturing process of the sulfide solid electrolyte can be suppressed. The element M is, in all cases, an element whose defect formation energy for N in a compound represented by Li α M β N (where α and β are numerical values that give the stoichiometric ratio depending on the type of element M) is 4.00 eV or greater, as calculated by first-principles calculations described later. The definition of the defect formation energy for N will be described later. The raw mate