Anode internal purge (AIP) technique for the co-optimization of system efficiency and stack reliability in air-cooled PEMFCs

• The AIP technique elevates stack system efficiency from 25.71% in DEA mode to 48.29%. • The maximum decrease ratio of the output average voltage of the AIP technique is only 0.6% comparing to the DEA mode under 200 mA/cm 2. • The stability of the AIP technique is also acceptable: during a 60-min durability test, the stack output voltage decay ratio under an optimized strategy is only 0.09%, while the value of the DEA mode reaches 0.19%. Air-cooled PEMFCs with dead-end anode (DEA) mode discharge much hydrogen during the purge procedure resulting a low system efficiency. This phenomenon becomes particularly pronounced at lower power levels. We propose an anode internal purge (AIP) technique which accomplishes anode purging internally without any hydrogen emission. The experiment results show that the stack with AIP technique and DEA mode shares a similar electrical efficiency around of 46.6% at a current density of 200 mA/cm 2 , but the stack system efficiency increases from 25.71% (under DEA mode) to 48.29% (under AIP technique). At 200 mA/cm 2 ,the maximum decrease ratio of the AIP technique’s average output voltage is only 0.6% comparing to the DEA mode, while under 300 mA/cm 2 , AIP technique voltage slightly exceeds DEA mode. It is also helpful to the fuel cell’s stability. A 60-min durability test shows that, the stack output voltage decay ratio under an optimized AIP strategy is 0.09%, while the value of the DEA mode reaches 0.19%.