Given the focus on a green H2 economy for a sustainable future, it is crucial to understand the degradation features of H2-focus electrochemical devices and systems, i.e., proton exchange membrane fuel cells and water electrolysis (PEM-based FC & WE). The current accelerated stress test and resulting degradation features are systematically investigated through comprehensive analysis, including a series of electrochemical, spectroscopic, tomographic, and microscopic characterization, assisted with a detailed structure examination of the electrode, membrane, and interface. However, numerous characteristic studies that aim to uncover these features under various dynamic operations are commonly employed to depend on the sophisticated laboratory stationary bulky facilities and instruments in the theater. Moving forward to real-world practical applications, i.e., H2 electrical vehicles, a miniaturized, mobile, low-cost, and user-friendly measurement and diagnostic tool is highly in demand. Considering the dependence of the performance and durability on the ion exchange/transport, and involvement of small particles, and the high possibility of dissolution, the time-dependent sensing and tracking of such traces of ions can provide fundamental insight into the activities and events within the PEM-based FC & WE devices and systems. Our recent efforts are dedicated to bridging the notable gap to develop electrochemical and transistor-based ion sensors integrated on a circuit chip towards real-time in-situ monitoring of the health and degradation status. This complementary work may also provide valuable guidelines for establishing a suitable accelerated stress test protocol to diagnose system durability, and for designing durable materials for long-term operation.