Wearable self-powered human motion sensors based on highly stretchable quasi-solid state hydrogel

Self-powered flexible sensors are highly favored and considered auspicious for wearable electronics due to their preferable flexibility and facilitation to integrate with various apparel products. As a wearable product, the sensors can be designed by a self-powered strategy powered with harvested low-grade heat from human body to meet the daily long-term use. The flexible thermoelectric generator (f-TEG) can harvest the human body heat to generate a thermovoltage driving the sensor directly. Herewith we report a wearable self-powered human motion sensor made from highly stretchable quasi-solid state hydrogel, which shows 2800% elongation at break and good strain sensitivity (GF=4, when the strain is 200%) and detects the movement and sound of human body. Further, the hydrogel based sensor can harvest the human body heat and generate a thermovoltage to drive the sensor directly, which exhibits an impressive gigantic Seebeck coefficient of approximate 11.5 mV K−1 at ambient temperature. Combining the merits of flexibility, environment friendly, sensitivity and thermoelectric performance at room temperature range together, we believe that the hydrogel based sensor will offer amble opportunities to numerous self-powered sensor applications like wearable electronics, sports, health and wellbeing.