Anhydrous Proton Conduction Through a Chemically Robust Electrolyte Enabling a High-Temperature Non-Precious Metal Catalyzed Fuel Cell

Small. 2024 Apr;20(16):e2308677. doi: 10.1002/smll.202308677. Epub 2023 Nov 27.

Abstract

Fuel cells offer great promise for portable electricity generation, but their use is currently limited by their low durability, excessive operating temperatures, and expensive precious metal electrodes. It is therefore essential to develop fuel cell systems that can perform effectively using more robust electrolyte materials, at reasonable temperatures, with lower-cost electrodes. Recently, proton exchange membrane fuel cells have attracted attention due to their generally favorable chemical stability and quick start-up times. However, in most membrane materials, water is required for proton conduction, severely limiting operational temperatures. Here, for the first time it is demonstrated that when acidified, PAF-1 can conduct protons at high temperatures, via a unique framework diffusion mechanism. It shows that this acidified PAF-1 material can be pressed into pellets with high proton conduction properties even at high temperatures and pellet thickness, highlighting the processibility, and ease of use of this material. Furthermore, a fuel cell is shown with high power density output is possible using a non-precious metal copper electrode. Acid-doped PAF-1 therefore represents a significant step forward in the potential for a broad-purpose fuel cell due to it being cheap, robust, efficient, and easily processible.

Keywords: anhydrous proton conduction; fuel cells; phosphoric acid; porous aromatic framework; sulfuric acid.