Sputtered cathodes for polymer electrolyte fuel cells: insights into potentials, challenges and limitations

Area of Science:

• Electrochemistry
• Materials Science
• Energy Conversion

Background:

• High platinum (Pt) loadings in polymer electrolyte fuel cells (PEFCs) hinder commercialization.
• Sputtering is a promising electrode preparation method for PEFCs due to thin-film capabilities and cost reduction.

Purpose of the Study:

• To summarize key studies on sputtered PEFCs, including non-carbon supported electrodes.
• To elucidate the crucial role of morphological differences between sputtered and ink-based electrodes on fuel cell performance.
• To investigate the electrochemical surface area (ECSA) and particle size effect in sputtered electrodes.

Main Methods:

• Review of existing studies on sputtered PEFCs.
• Analysis of morphological differences between sputtered and ink-based electrodes.
• Investigation of a model system using a rotating disc electrode (RDE).

Main Results:

• Sputtered electrodes exhibit higher surface-specific activity (i(k,spec)) due to thin-film formation and the particle size effect.
• Lowering Pt loadings to 100 μg(Pt)/cm(2) in sputtered PEFC cathodes resulted in performance losses compared to ink-based electrodes.
• Pt sputtered electrodes on carbon support achieved high current densities (0.46 A/cm(2) at 0.6 V).

Conclusions:

• Understanding morphological differences is vital for optimizing sputtered PEFC performance.
• The particle size effect contributes to the enhanced activity of sputtered electrodes.
• Further research is needed to overcome performance losses at reduced Pt loadings in sputtered PEFCs.