Flexible Ag/AgCl quasi-reference electrode with nano silver dendrites semi-embedded in PDMS: Ensuring long operation lifespan, remarkable stability for electrophysiological monitoring and flexible sensor applications

Flexible sheet reference electrodes play a crucial role in both flexible electrochemical biosensors and electrophysiological monitoring. Enhancing electrode stability and extending continuous operational lifespan are key issues in the research of flexible sheet reference electrodes. In this study, a novel flexible Ag/AgCl sheet reference electrode was fabricated by semi-embedding nano-silver dendrites within a polydimethylsiloxane (PDMS) matrix. The flexible Dendritic Ag/AgCl quasi-reference electrodes showed comparable stability of open circuit potential to commercial glass reference electrodes, with a single continuous stable operation time exceeding 12 h and sustained stable operation for at least 30 days when operated continuously for 1 h per day. Additionally, the shelf life was significantly extended to at least 1 year. An in-depth exploration of its mechanism reveals that the embedding strategy plays a crucial role. It strengthens the tight connections between silver dendrites, forming a robust and stable conductive network that ensures rapid and stable charge transfer. Furthermore, the strong adhesion between silver dendrites and PDMS greatly enhances its mechanical durability. This electrode exhibits high practical value in electrophysiological monitoring such as electroencephalogram and electrocardiogram, as well as in flexible sensor applications for H 2 O 2 sensing in pleural effusions, opening new pathways for advancements in flexible wearable devices and biomedical sensor technologies.