3D-Zipped Interface: In Situ Covalent-Locking for High Performance of Anion Exchange Membrane Fuel Cells

Polymer electrolyte membrane fuel cells can generate high power using a potentially green fuel (H-2) and zero emissions of greenhouse gas (CO2). However, significant mass transport resistances in the interface region of the membrane electrode assemblies (MEAs), between the membrane and the catalyst layers remains a barrier to achieving MEAs with high power densities and long-term stabilities. Here, a 3D-interfacial zipping concept is presented to overcome this challenge. Vinylbenzyl-terminated bi-cationic quaternary-ammonium-based polyelectrolyte is employed as both the anionomer in the anion-exchange membrane (AEM) and catalyst layers. A quaternary-ammonium-containing covalently locked interface is formed by thermally induced inter-crosslinking of the terminal vinyl groups. Ex situ evaluation of interfacial bonding strength and in situ durability tests demonstrate that this 3D-zipped interface strategy prevents interfacial delamination without any sacrifice of fuel cell performance. A H-2/O-2 AEMFC test demonstration shows promisingly high power densities (1.5 W cm(-2) at 70 degrees C with 100% RH and 0.2 MPa backpressure gas feeds), which can retain performances for at least 120 h at a usefully high current density of 0.6 A cm(-2).

Automated summary

By introducing a 3D-interfacial zipping concept, the challenges of mass transport resistances in polymer electrolyte membrane fuel cells are addressed, leading to enhanced power densities and long-term stabilities. The use of a bi-cationic quaternary-ammonium-based polyelectrolyte creates a covalently locked interface that prevents delamination without sacrificing fuel cell performance, as demonstrated in ex situ and in situ tests. A high power density of 1.5 W cm(-2) was achieved in a H-2/O-2 AEMFC test, with performance retention for at least 120 hours at a high current density of 0.6 A cm(-2).