Compared to PEMFCs, AEMFCs face mor

Compared to PEMFCs, AEMFCs face more complicated watermanagement issues. In PEMFCs, water is only generated at thecathode as a product and not electrochemically consumed.Water ismoved to the cathode from the anode by electro-osmotic drag asH+ is produced by HOR. Thus, removing water from the cathodeis the primary concern in the PEMFC to avoid catastrophic electrode flooding. In AEMFCs, two water molecules are consumed inthe cathode while four water molecules are generated in the anode, and therefore the speed of water generation is two time fasterthan the water consumption. That is, the water management between the anode and cathode is important in AEMFCs since the ion conduction is actually based on water transport. Omasta et al.[10] indicated the importance of water balancing in the anode andthe cathode based on BTMA-ETFE ionomers, and the moderate RHresponded positively to address the anode flooding issues. Importantly, the high rate of water back diffusion from the anode toward cathode can naturally prevent from the anode flooding andthe cathode dry-out issues.