The polymer electrolyte membrane fuel cell (PEMFC) generates electrical energy through electrochemical reactions and is a key technology for sustainable energy. The electrolyte membrane significantly affects performance under varying conditions. This study examines the impact of membrane thickness and relative humidity (RH) on PEMFC performance using j-V curves and electrochemical impedance spectroscopy (EIS). Experiments were conducted with membrane thicknesses of 30, 15, and 5 μm under RH conditions of 100%-100% and 100%-0%. Under RH 100%-100%, performance improved as the membrane thickness decreased, with values of 954, 1050, and 1235 mW/cm² for the 30, 15, and 5 μm membranes, respectively. The 5 μm membrane demonstrated a 23% performance improvement over the 30 μm membrane. Under RH 100%-0%, performances were 422, 642, and 852 mW/cm², with degradation rates of 55.8%, 39.0%, and 32.1%. The 5 μm membrane exhibited the lowest degradation rate, indicating superior performance under low humidity. These results suggest that thinner membranes generally enhance performance and maintain efficiency even in dry conditions.

Intrinsically stretchable electronics enable seamless integration with dynamic biological tissues and curved surfaces, making them vital for next-generation wearables, biointerfaces, and intelligent robotics. Yet, precise, high-resolution patterning of stretchable electrodes and circuits remains challenging, limiting practical applications. Traditional lithography offers excellent resolution but is hindered by thermal and chemical incompatibilities with soft substrates. Consequently, alternative approaches such as soft lithography, laser-based patterning, printing methods, and electrospray deposition have gained importance. Soft lithography provides an economical, low-temperature option suitable for delicate materials like liquid metals. Laser-based techniques deliver high resolution and design flexibility but require careful parameter tuning for specific substrates. Mask-free printing methods, including direct ink writing and inkjet printing, enable versatile patterning of complex geometries, while electrospray deposition supports precise, non-contact patterning on stretchable surfaces. Collectively, these techniques advance the fabrication of robust stretchable displays, wireless antennas, and bioelectronic interfaces for accurate physiological monitoring. Despite progress, challenges persist, particularly in achieving large-area uniformity, multilayer stability, and sustainable processing. Addressing these issues demands interdisciplinary collaboration across materials science, fluid dynamics, interfacial engineering, and digital manufacturing. This review highlights recent progress and remaining hurdles, offering guidance for future research in stretchable electronics.