Improved membrane electrode assemblies for PEM fuel cells

Abstract

The invention relates to Membrane Electrode Assemblies ("MEAs") for solid- polymer-electrolyte proton-conducting membrane fuel cells ("PEM-FCs") having better performance and improved durability, in particular when operated under severe electro-chemical conditions such as fuel starvation and start-up / shut-down cycling. The MEAs are characterized in that at least one of its two electrode layers (EL and / or EL2) contains a first electrocatalyst (EC1) comprising an iridium oxide component in combination with at least one other inorganic oxide component anda second electrocatalyst (EC2 / EC2'), which is free from iridium. Preferably, an iridium oxide / titania catalyst is employed as EC1. The MEAs reveal better performance, in particular when operated under severe operating conditions such as fuel starvation and start-up / shut-down cycling.

Description

field of invention

[0001] The present invention relates to membrane electrode assemblies ("MEAs") for solid-polymer-electrolyte proton-conducting membrane fuel cells ("PEM-FCs") having better performance and improved durability, especially when operating under a variety of harsh electrochemical conditions. Background of the invention

[0002] Fuel cells (FCs) are electrochemical devices for generating electricity that are used or are commercially foreseen for a variety of different applications including, for example, automotive powertrains, stationary units for residential heating, onboard auxiliary power units, portable electronics, remote or Portable spare units, etc.

[0003] A PEM fuel cell (PEM-FC) is more specifically a fuel cell comprising a solid-polymer-electrolyte membrane (hereinafter referred to as "membrane" for convenience), such as a proton-conducting perfluorosulfonic acid membrane or a hydrocarbon acid membrane) fuel cell. A PEM fuel cell also includes a...

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