Understanding on Electrochemical Structure of Low Temperature Proton Exchange Membrane Fuel Cells

Membrane electrode assembly (MEA) is the heart of a PEM fuel cell. In the catalyst layer, the electrochemical reactions only happen on the catalyst, which has simultaneous access to proton, electron and gas. Therefore, it is also called three-phase boundary (TPB). The larger and more stable TPB, the better performance of the cell will be.

Different from fundamental material studies, catalyst performance was evaluated based on the electrode structure point of view. Interaction between catalyst or catalyst support with Nafion ionomer was systematically investigated through an adsorption isotherm study[i], [ii]. Various adsorption strengths were observed depending on the surface properties of the absorbent. The structure of the resulting catalyst-ionomer-electrode (CIE) and the corresponding degradation pattern due to accelerated stress test were monitored with X-ray photoelectron spectroscopy[iii]. Based on our earlier studies[iv], the polymer phase can directly influence the other two phases in the electrode. Degradation of the polymer / corruption of the interphase structure in the catalyst layer can be the bottle neck of the overall challenge. Corresponding strategy for the improvement is proposed.

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[i] Carbon, 71 (2014) 218-228.

[ii] J. Phy. Chem. C, 118 (2014) 10814–10823.

[iii] J. Power Sources, 274 (2015) 1217-1223.

[iv] ACS Appl. Mater. Interfaces 6 (2014) 16565−16576.

See more of: Batteries, Fuel Cells and Electrolyzers
See more of: I03: Materials for Low-Temperature Electrochemical Systems 2
See more of: Fuel Cells, Electrolyzers, and Energy Conversion

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