US-20260125805-A1 - MEMBRANE ELECTRODE ASSEMBLY FOR WATER ELECTROLYSIS AND METHOD FOR MANUFACTURING THE SAME

US20260125805A1US 20260125805 A1US20260125805 A1US 20260125805A1US-20260125805-A1

Abstract

A membrane electrode assembly for water electrolysis includes a solid electrolyte membrane, and an anode catalyst layer and a cathode catalyst layer that sandwich the solid electrolyte membrane. The solid electrolyte membrane includes a solid electrolyte layer, and a functional layer provided on an anode-side surface of the solid electrolyte layer. The anode catalyst layer is provided on a surface of the solid electrolyte membrane near the functional layer. The cathode catalyst layer is provided on a surface of the solid electrolyte membrane opposite to the functional layer. The functional layer contains a resin and catalytic metal particles dispersed in the resin.

Inventors

Tomoki Kodama
Yasuhiro Akita

Assignees

TOYOTA JIDOSHA KABUSHIKI KAISHA

Dates

Publication Date: 20260507
Application Date: 20250708
Priority Date: 20241106

Claims (4)

1 . A membrane electrode assembly for water electrolysis, the membrane electrode assembly comprising a solid electrolyte membrane, and an anode catalyst layer and a cathode catalyst layer that sandwich the solid electrolyte membrane, wherein the solid electrolyte membrane includes a solid electrolyte layer, and a functional layer provided on an anode-side surface of the solid electrolyte layer, the anode catalyst layer is provided on a surface of the solid electrolyte membrane near the functional layer, the cathode catalyst layer is provided on a surface of the solid electrolyte membrane opposite to the functional layer, and the functional layer contains a resin and catalytic metal particles dispersed in the resin.
2 . The membrane electrode assembly according to claim 1 , wherein the catalytic metal particles contain one or more kinds selected from the group consisting of Pt, Au, Pd, Rh, and Ir.
3 . A method for manufacturing a membrane electrode assembly for water electrolysis, the method comprising: preparing an electrolyte membrane sheet including an existing back sheet and a solid electrolyte membrane attached to the existing back sheet, the solid electrolyte membrane including a solid electrolyte layer and a functional layer provided on a surface of the solid electrolyte layer opposite to the existing back sheet; attaching a fresh back sheet to a surface of the solid electrolyte membrane near the functional layer through thermocompression bonding by laminating the electrolyte membrane sheet and the fresh back sheet to form a laminate such that the fresh back sheet is in contact with the surface of the solid electrolyte membrane near the functional layer, and heating the laminate while pressurizing the laminate from both sides in a laminating direction; peeling the existing back sheet from the solid electrolyte membrane; forming a cathode catalyst layer on a surface of the solid electrolyte membrane opposite to the functional layer after the peeling of the existing back sheet; peeling the fresh back sheet from the solid electrolyte membrane after the forming of the cathode catalyst layer; and forming an anode catalyst layer on the surface of the solid electrolyte membrane near the functional layer after the peeling of the fresh back sheet.
4 . The method for manufacturing the membrane electrode assembly according to claim 3 , wherein, in the attaching, a heating temperature when heating the laminate while pressurizing the laminate from both the sides in the laminating direction is 120° C. or more and a thermal decomposition temperature or less.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application claims priority to Japanese Patent Application No. 2024-194130 filed on Nov. 6, 2024. The disclosure of the above-identified application, including the specification, drawings, and claims, is incorporated by reference herein in its entirety. BACKGROUND 1. Technical Field The present disclosure relates to a membrane electrode assembly for water electrolysis to be used in a water electrolysis device, and a method for manufacturing the membrane electrode assembly for water electrolysis. 2. Description of Related Art In recent years, water electrolysis devices in which a predetermined number of water electrolysis cells using solid electrolyte membranes are arranged have been adopted. Such a water electrolysis cell includes a membrane electrode assembly including a solid electrolyte membrane and an anode catalyst layer and a cathode catalyst layer that sandwich the solid electrolyte membrane. As the membrane electrode assembly for water electrolysis, for example, there is known a membrane electrode assembly in which a catalyst layer is formed using a catalyst layer forming material containing catalyst particles and an electrolyte component as main components, and the catalyst particles and the electrolyte component that form the catalyst layer have a gradient in distribution such that the electrolyte component in the catalyst layer is not unevenly distributed in the vicinity of the surface of the catalyst layer (Japanese Unexamined Patent Application Publication No. 2001-303285 (JP 2001-303285 A)). As a method for manufacturing the membrane electrode assembly for water electrolysis, for example, there is disclosed a method including: a first forming step of forming either an anode catalyst layer or a cathode catalyst layer on a second surface opposite to a first surface of an elongated electrolyte membrane, with a support film that holds the electrolyte membrane in a stretched state being attached to the first surface; a first attaching step of peeling a support member from the first surface of the electrolyte membrane and attaching, to the second surface, a diffusion member that constitutes a diffusion layer for diffusing a fluid that constitutes fuel or an oxidant required for electrochemical reaction in a fuel cell; a second forming step of forming the other catalyst layer on the first surface; and a second attaching step of attaching the diffusion member to the first surface. The method is performed by a roll-to-roll process (Japanese Unexamined Patent Application Publication No. 2015-35256 (JP 2015-35256 A)). SUMMARY In the membrane electrode assembly for water electrolysis and the manufacturing method according to the related art, the composition of and the formation method for the catalyst layer have been improved to improve the water electrolysis performance of the water electrolysis cell. To ensure the safety of the water electrolysis cell, it is necessary to suppress generation of explosive oxyhydrogen gas by blocking permeation of hydrogen gas generated on the cathode side through the solid electrolyte membrane. There is a demand to improve the blocking performance against the permeation of hydrogen gas through the solid electrolyte membrane. The present disclosure has been made in view of the above circumstances, and an object of the present disclosure is to provide a membrane electrode assembly for water electrolysis that can improve blocking performance against permeation of hydrogen gas through a solid electrolyte membrane, and to provide a method for manufacturing the membrane electrode assembly for water electrolysis. In order to solve the above problem, a membrane electrode assembly according to the present disclosure is a membrane electrode assembly for water electrolysis. The membrane electrode assembly includes a solid electrolyte membrane, and an anode catalyst layer and a cathode catalyst layer that sandwich the solid electrolyte membrane. The solid electrolyte membrane includes a solid electrolyte layer, and a functional layer provided on an anode-side surface of the solid electrolyte layer. The anode catalyst layer is provided on a surface of the solid electrolyte membrane near the functional layer. The cathode catalyst layer is provided on a surface of the solid electrolyte membrane opposite to the functional layer. The functional layer contains a resin and catalytic metal particles dispersed in the resin. A method for manufacturing a membrane electrode assembly according to the present disclosure is a method for manufacturing a membrane electrode assembly for water electrolysis. The method includes: preparing an electrolyte membrane sheet including an existing back sheet (sometimes abbreviated as “BS”) and a solid electrolyte membrane attached to the existing back sheet, the solid electrolyte membrane including a solid electrolyte layer and a functional layer provided on a surface of the solid electrolyte layer opposite to the exi