Evolution Mechanism of the Structure and Performance of Silver-Based Printed Circuits Under Electromechanical Coupling Loads

Silver-based printed circuits have demonstrated significant potential in the field of flexible electronics, particularly for applications such as wearable devices, owing to their high conductivity, low cost, and ease of mass production. However, their structural and performance degradation under continuous mechanical and electrical loads during service poses a major challenge to achieving long-term stable functionality. Herein, this study investigates the performance and microstructural evolution of silver-based printed circuits under electromechanical coupling loads and unveils the underlying material degradation mechanisms. Resistance change curves reveal that, under identical bending loads, lower current density (208.3 A/cm²) accelerates circuit degradation more significantly than higher current density (1164.7 A/cm²). By analysing the thermal characteristics, conductive phase structure, and conductive network of printed circuits under mechanical loading, electric field stimulation, and electromechanical coupling, it is evident that heat plays a critical role in determining resistance changes in silver-based printed circuits. At lower temperatures, heat-induced oxidation of nanosilver to nonconductive silver oxide emerges as the primary driver of resistance increase. Conversely, at higher temperatures, heat-induced sintering of silver forms new conductive pathways that offset the resistance increase caused by the oxidation of silver nanoparticles. These findings not only elucidate the fatigue degradation mechanisms of silver-based printed circuits but also offer theoretical guidance for the development of high-performance silver-based printed circuits.