Coaxial Nanowire Electrodes Enable Exceptional Fuel Cell Durability

Abstract

Polymer‐electrolyte‐membrane fuel cells (PEMFCs) hold great promise for applications in clean energy conversion, but cost and durability continue to limit commercialization. This work presents a new class of catalyst/electrode architecture that does not rely on Pt particles or carbon supports, eliminating the primary degradation mechanisms in conventional electrodes, and thereby enabling transformative durability improvements. The coaxial nanowire electrode (CANE) architecture consists of an array of vertically aligned nanowires, each comprising an ionomer core encapsulated by a nanoscale Pt film. This unique design eliminates the triple‐phase boundary and replaces it with two double‐phase boundaries, increasing Pt utilization. It also eliminates the need for carbon support and ionomer binder, enabling improved durability and faster mass transport. Fuel cell membrane electrode assemblies based on CANEs demonstrate extraordinary durability in accelerated stress tests (ASTs), with only 2% and 5% loss in performance after 5000 support AST cycles and 30000 catalysts AST cycles, respectively. The high power density and extremely high durability provided by CANEs can enable a paradigm shift from random electrodes based on unstable platinum nanoparticles dispersed on carbon to ordered electrodes based on durable Pt nanofilms, facilitating rapid deployment of fuel cells in transportation and other clean energy applications.

It's time for an update—A perspective on fuel cell electrodes

“…1. Coaxial nanowire electrodes reported by Yang et al [15] feature Nafion ® nanowires aligned in the direction perpendicular to the plane of the membrane, coated with a thin film of Pt (coated via atomic layer deposition). The Nafion ® nanowires enable facile proton transport across the thickness of the electrode, while the thin Pt film is ionomer-free which eliminates oxygen transport resistance associated with permeation through the…”

Fabrication of Hydrogen-Permeable Ni–Zr Thin Films for Efficient Hydrogen Separation and Their Application in Graphene Oxide-Hydrogen Membrane Fuel Cells

“…Among various types of fuel cells, PEMFCs stand out by utilizing a proton exchange membrane (PEM) as an electrolyte. These fuel cells possess distinctive advantages, such as low-temperature operation, high power density, and excellent proton conductivity. − As a consequence, it is considered the next-generation clean energy source suitable for various applications, encompassing stationary uses and prospective automotive applications . In traditional PEMFCs, the anode and cathode typically consist of carbon-supported Pt (Pt/C) electrocatalysts, with Nafion (R) serving as the perfluorinated ionomer membrane for electrolyte purposes. , Nafion (R) displays outstanding thermal and chemical stability while also demonstrating excellent proton conductivity, making it an exceptional conductor that encompasses the characteristics of both a solid-phase hopping conductor and liquid-phase vehicle conduction. , However, Nafion (R) also presents certain drawbacks, such as high production costs, limited economic feasibility, unsuitability for mass production, the proton conductivity exhibits quick changes depending on the hydration status, chemical degradation of Nafion (R) by hydrogen peroxide and other radicals, and severe degradation at temperatures exceeding 100 °C. ,, Consequently, the exploration of Nafion-free ionomers has garnered substantial research interest.…”