Stretch-responsive triboelectric nanogenerator based on conductive PVA/AC hydrogel for human activity monitoring

• This study introduces a skin-integrated, flexible, and stretchable self-powered flexion sensor utilizing a stretch-responsive triboelectric nanogenerator (SR-TENG) for monitoring human motion. • The proposed device is fabricated using a conductive Poly (Vinyl Alcohol)/Activated Carbon hydrogel electrode, enabling efficient energy harvesting and real-time motion detection. • Systematic studies on the surface and microstructures of the stretchable SR-TENG reveal that optimizing the surface roughness of Ecoflex triboelectric layers and the porosity of the PVA/AC hydrogel electrode significantly enhances electrostatic induction and improves electrical output performance. • The mechanical stability and stretchability of the proposed SR-TENG were evaluated using a universal tensile testing machine, ensuring its durability and performance under mechanical deformation. • These assessments confirm the device's reliability for applications in wearable energy harvesting and human motion monitoring. Flexible and stretchable triboelectric nanogenerators (TENGs) are promising energy harvesters and tactile sensors capable of capturing and converting mechanical energy from daily activities into electrical signals. Their ability to function as self-powered devices makes them ideal for various applications, including wearable electronics and interactive sensing technologies. This study introduces a skin-integrated, flexible, and stretchable self-powered flexion sensor utilizing a stretch-responsive triboelectric nanogenerator (SR-TENG) for monitoring human motion. The proposed device is fabricated using a conductive poly (vinyl alcohol)/activated carbon hydrogel electrode, enabling efficient energy harvesting and real-time motion detection. The developed SR-TENG demonstrates the potential for wearable sensing applications, offering a reliable and sustainable solution for human activity monitoring. Systematic studies on the surface and microstructures of the stretchable SR-TENG reveal that optimizing the surface roughness of Ecoflex triboelectric layer and the porosity of the PVA/AC hydrogel electrode significantly enhances electrostatic induction and improves electrical output performance. As a result, the SR-TENG generates a maximum instantaneous voltage of 69 V and a peak instantaneous power density of 11.40 µW/cm 2 , demonstrating its potential for efficient self-powered applications. The mechanical stability and stretchability of the proposed SR-TENG were evaluated using a universal tensile testing machine, ensuring its durability and performance under mechanical deformation. These assessments confirm the device's reliability for applications in wearable energy harvesting and human motion monitoring. The SR-TENG, demonstrated as a simple skin-attachable patch, effectively monitors physiological signals such as muscle movement; this showcases its potential for sensing and energy generation, emphasizing its applicability in wearable health monitoring systems.