Operando characterization of the internal multi-fields of industrial-scale fuel cells and mechanistic insight

Despite significant progress in fuel cell technology, its large-scale industrial application is still challenged by the frequently encountered performance failure during long-term operation. Clarifying the failure mechanism is the key to extending the lifecycle and enhancing stability. Herein, we have developed a time and space resolved multi-field characterization, including electrochemical impedance spectroscopy, to unveil its underlying mechanism. With this operando and non-destructive characterization, the dynamic evolution of the internal mass transport, heat, and electricity field distribution is fully depicted within an industrial-scale fuel cell in operation. Thus, it is revealed that hydrogen starvation occurs in the outlet region due to the excessive hydrogen consumption during the loading-down process. This can induce local low current density and carbon corrosion, which may subsequently cause severe damage to the structure of the catalyst layer and membrane, ultimately leading to performance failure. With this understanding, we further identify a descriptor for early diagnosis to prevent any potential degradation. The methodology is of significance, which can bring fuel cell technology a step further towards industrial applications.