Impact of inlet CO2 on the performance of AEMFCs: Mechanistic insights and mitigation strategies
DOI:
https://doi.org/10.18686/cest369Keywords:
AEMFC; CO2; AEM; operational condition; pre-treatment systemAbstract
Anion exchange membrane fuel cells (AEMFCs) offer a lower assembly cost compared to proton exchange membrane fuel cells (PEMFCs), as their alkaline environment enables the use of inexpensive catalysts and bipolar plates. Currently, most performance evaluations of AEMFCs are conducted with O2 as the cathode gas. However, the ultimate goal of AEMFCs is to operate with ambient air as the cathode feed. CO2 in the air often exerts a significant negative impact on AEMFC performance, particularly by reducing the conductivity of the alkaline electrolyte and diminishing the overall efficiency of the cell. This challenge has become one of the primary barriers to the widespread adoption and optimization of AEMFC technology. This work reviews relevant studies by previous researchers and identifies three main mechanisms through which CO2 adversely affects AEMFC performance: (1) the formation of carbonate ions, which reduces the effective conductivity of the membrane; (2) the increase in anode potential, leading to voltage loss; and (3) the accumulation of carbonates, which raises the charge transfer resistance. Furthermore, this work summarizes strategies to mitigate or prevent AEMFC carbonation, focusing on membrane property modulation, operational condition optimization, and the design of the inlet air pre-treatment systems. The review aims to provide a comprehensive framework for both academic and industrial stakeholders, facilitating the advancement of AEMFC technology.
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