Membrane electrode assembly, electrochemical cell, and electrochemical device

Abstract

A membrane electrode assembly includes a pair of electrodes, each having a feeder layer that is porous and made of a conductive material, and an electrolyte membrane disposed between the pair of electrodes. At least one of the electrodes has a catalyst layer disposed in the feeder layer. In a cross section of the feeder layer, an electrolyte exists in a first region less than or equal to 80% of a thickness of the feeder layer from the electrolyte membrane toward an opposite direction to the electrolyte membrane, the catalyst layer exists at 50% or more of an outer circumference of a cross section of the conductive material in the first region, and the catalyst layer exists at 10% or less of the outer circumference of the cross section of the conductive material in a second region other than the first region.

What is claimed is: 
     
         1 . A membrane electrode assembly, comprising:
 a pair of electrodes, each having a feeder layer that is porous and made of a conductive material; and   an electrolyte membrane disposed between the pair of electrodes,   wherein at least one of the electrodes has a catalyst layer disposed in the feeder layer, and, in a cross section of the feeder layer,   an electrolyte exists in a first region less than or equal to 80% of a thickness of the feeder layer from the electrolyte membrane toward an opposite direction to the electrolyte membrane,   the catalyst layer exists at 50% or more of an outer circumference of a cross section of the conductive material in the first region, and   the catalyst layer exists at 10% or less of the outer circumference of the cross section of the conductive material in a second region other than the first region.   
     
     
         2 . The membrane electrode assembly according to  claim 1 , wherein the catalyst layer is a laminated structure including an aggregate layer and a void layer. 
     
     
         3 . The membrane electrode assembly according to  claim 2 , wherein a thickness of the aggregate layer is 4 nm or more and 30 nm or less. 
     
     
         4 . The membrane electrode assembly according to  claim 1 , wherein a porosity of the feeder layer is 40% or more and 90% or less. 
     
     
         5 . The membrane electrode assembly according to  claim 1 , wherein the feeder layer is made of a metal non-woven fabric having a fiber length of 1 μm or more and 100 μm or less. 
     
     
         6 . The membrane electrode assembly according to  claim 1 , wherein the feeder layer is made of a metal sintered body of particles of 1 μm or more and 100 μm or less. 
     
     
         7 . The membrane electrode assembly according to  claim 1 , wherein the thickness of the feeder layer is 50 μm or more and 2000 μm or less. 
     
     
         8 . An electrochemical cell, comprising:
 a membrane electrode assembly according to  claim 1 ; and   a pair of separators having the membrane electrode assembly sandwiched therebetween.   
     
     
         9 . An electrochemical device comprising the electrochemical cell according to  claim 8 . 
     
     
         10 . The electrochemical device of  claim 9 , wherein the electrochemical device is a hydrogen production device.