Thermally chargeable supercapacitor modules with heat transporting systems for powering wireless sensors by natural heat dissipation

• Commercial wireless sensors could be driven by cold start. • Heat pipe efficiently transfers heat to the part of the TCS module. • Heat sink dissipates heat to environments. • The developed systems are feasible for using thermal energy. Heat-to-electricity energy conversion is one of the most important sources for powering various wireless sensors in the future Internet of Things (IoT). In this study, we developed a new class of thermoelectric modules using redox-free electrolytes, namely thermally chargeable supercapacitors (TCS), with extensively large thermoelectromotive force of over 4 V without a DC-to-DC converter. The commercial wireless sensors are driven by the cold start owing to the large voltage output. Furthermore, we combined the TCS module with a heat-dissipation system which uses a heat pipe and sink. The heat pipe efficiently transfers heat to the part of the TCS module, while the heat sink dissipates the heat to the environment, enabling the supply of sufficient temperature difference to the TCS module by natural cooling. The large output voltage generated was further managed by the voltage detector integrated circuit to intermittently power the wireless sensors. The developed systems can use thermal energy even when the heat sources are spatially separated from the sensor units. We believe the proposed device and thermal engineering promote sustainable energy production by harvesting low-grade thermal energy and reducing energy consumption through IoT.