Alkaline polymer electrolyte fuel cells completely free from noble metal catalysts

TLDR

Fuel cell technology has advanced with polymer electrolytes, yet acidic polymer electrolytes still rely on costly noble metal catalysts, limiting widespread adoption. The authors aim to create a polymer electrolyte fuel cell that eliminates noble metal catalysts by using an alkaline electrolyte. They employ quaternary ammonium polysulphone as the hydroxide‑ion conductive electrolyte and chromium‑decorated nickel and silver as the negative and positive electrode catalysts. The resulting H₂–O₂ fuel cell operates without noble metals, with nickel surface tuning suppressing oxidative passivation while maintaining hydrogen‑oxidation activity, demonstrating a significant advance.

Abstract

In recent decades, fuel cell technology has been undergoing revolutionary developments, with fundamental progress being the replacement of electrolyte solutions with polymer electrolytes, making the device more compact in size and higher in power density. Nowadays, acidic polymer electrolytes, typically Nafion, are widely used. Despite great success, fuel cells based on acidic polyelectrolyte still depend heavily on noble metal catalysts, predominantly platinum (Pt), thus increasing the cost and hampering the widespread application of fuel cells. Here, we report a type of polymer electrolyte fuel cells (PEFC) employing a hydroxide ion-conductive polymer, quaternary ammonium polysulphone, as alkaline electrolyte and nonprecious metals, chromium-decorated nickel and silver, as the catalyst for the negative and positive electrodes, respectively. In addition to the development of a high-performance alkaline polymer electrolyte particularly suitable for fuel cells, key progress has been achieved in catalyst tailoring: The surface electronic structure of nickel has been tuned to suppress selectively the surface oxidative passivation with retained activity toward hydrogen oxidation. This report of a H 2 –O 2 PEFC completely free from noble metal catalysts in both the positive and negative electrodes represents an important advancement in the research and development of fuel cells.