Performance stability of a bimetallic ORR catalyst (Fe,Co-N-C) in PEMFC under different relative humidities

Studying the durability of proton exchange membrane fuel cells (PEMFC) requires long-term tests, including aging cycles and accelerated stress tests (AST), but the study of their performance stability can be done in the short term with tests such as constant voltage technique (chronoamperometry), and the amount of fluctuation can be checked in the output current of the PEMFC during operation. The development of fuel cell usage in various environments requires the ability to operate these systems in different operational and environmental conditions [1], this mechanism of changing the output power of the PEMFC according to the operating conditions is called the system dynamic response process [2], which affects the efficiency of the system and many researches have been done in this field [3]. But in the systems where MOF-based electrocatalysts are used in their cathode, due to the need for high humidity level by the catalyst layer and to improve the performance of the membrane in high humidity levels, fluctuation in membrane-electrode assembly (MEA) performance occurs in different conditions. In such a way that the performance of the system in the long term is usually optimal at high levels of humidity [4], and with a decrease in the relative humidity of the cathode, due to reasons such as drying and increasing the resistance of the membrane and decreasing the available triple phase boundaries (TPB), the efficiency of the system decreases. Therefore, the performance stability in different values of the cathode relative humidity was investigated.