A Self-Powered Hydrogel-Based Wearable Sensor for Sports Motion Monitoring and Activity Recognition

Wearable sensors have shown great potential in sports motion monitoring, exercise evaluation, and intelligent training owing to their ability to provide continuous and real-time biomechanical information. Here, a multinetwork PD hydrogel-based triboelectric nanogenerator (PD-TENG) is developed as a self-powered wearable sensing platform for national fitness motion monitoring and intelligent evaluation. The device adopts a contact-separation configuration with pPTFE and nylon as the triboelectric pair and PD hydrogel as the flexible conductive electrode. Benefiting from the synergistic coupling of polymer chains, ionic species, and dynamic intermolecular interactions, the hydrogel exhibits favorable flexibility, mechanical compliance, and interfacial adaptability. The optimized PD-TENG delivers an open-circuit voltage (V_OC) of 876 V, a short-circuit current (I_SC) of 40 μA, a transferred charge (Q_SC) of 260 nC, and a maximum output power of 598 μW. It also maintains stable electrical performance under varying frequencies, separation distances, temperature, humidity, and external force. As a wearable sensor, it enables joint-angle monitoring and distinguishes walking, running, and jumping, demonstrating promising potential for intelligent motion recognition and scoring.