Self-Powered, Non-Toxic, Recyclable Thermogalvanic Hydrogel Sensor for Temperature Monitoring of Edibles

Thermogalvanic hydrogel, an environmentally friendly power source, enable the conversion of low-grade thermal energy to electrical and powers microelectronic devices in a variety scenarios without need for additional batteries. Its toxicity, mechanical fragility low output performance are hindrance its wide application. Here, we demonstrate thermoelectric gels with safe non-toxic, recyclable, highly transparent flexible stretchable properties by introducing gelatin as polymer network SO3/42− redox electric pair. When temperature difference is 10 K, gel-based thermogalvanic cell achieves open-circuit voltage about 16.2 mV maximum short-circuit current 39 μA. Furthermore, extended application Gel-SO3/42− gel monitor hot or cold food, enabling self-powered sensing food detection. This research provides novel concept harvesting achieving harmless self-driven monitoring.