Thermoelectric Generator Through Dual‐Direction Thermal Regulation by Thermal Diodes for Waste Heat Harvesting

Abstract Thermal energy harvesting provides an opportunity for multi‐node systems to achieve self‐power autonomy. Thermoelectric generators (TEGs), either by thermocouple arrangement with higher‐aspect‐ratios or thermoelectric films overlay, are limited by the small temperature difference and its short‐duration (less than dozens of minutes), hindering the harvesting efficiency. Here, by introducing thermal diodes with dual‐direction thermal regulation ability to optimize the heat flux path, the proposed TEGs exhibit enhanced power‐supply capability with unprecedented long‐duration (more than hours). In contrast with conventional TEGs with fixed‐leg dimensions enabled single output, these compact‐TEGs can supply up to fourteen output‐channels for selection, the produced power ranges from 1.11 to 921.99 µW, open circuit voltage ranges from 8.07 to 51.32 mV, when the natural temperature difference is 53.84 °C. Compared to the most recent TEGs, the proposed TEGs in this study indicate higher power (more than hundreds times) and much longer output duration (2.4–120 times) in a compact manner.