A flexible silver–aluminum conductive silicone triboelectric sensor for wearable physiological and motion monitoring

Flexible triboelectric sensors are promising for wearable physiological and motion monitoring by converting body-induced mechanical stimuli into electrical signals. However, stable sensing across different signal scales, from subtle physiological fluctuations to large-amplitude body motions, remains challenging. Here, a flexible silver–aluminum conductive silicone-based triboelectric sensor, named SACS-sensor, is developed for wearable physiological and motion sensing. The device adopts a single-electrode structure, in which the silver–aluminum conductive silicone serves as the flexible electrode and the outer silicone rubber functions as both the encapsulation layer and triboelectric contact interface. The sensor exhibits repeatable force-dependent outputs over 20–200 N, with segmented linear sensitivities of 0.130 V N−1 below 100 N and 0.040 V N−1 above 100 N. It also maintains stable electrical output after 10 000 loading cycles. When attached to the wrist, the sensor captures coupled pulse–respiration signals, which can be separated by frequency-domain filtering. It further enables monitoring of throat-related activities and multi-joint motions. This study provides a simple and flexible triboelectric sensing strategy for wearable physiological and motion monitoring.