Elevating Low-Grade Heat Harvesting with Daytime Radiative Cooling and Solar Heating in Thermally Regenerative Electrochemical Cycles.

Thermal radiation control has garnered growing interest for its ability to provide localized cooling and heating without energy consumption. However, its direct application for energy harvesting remains largely underexplored. In this work, we demonstrate a novel system that leverages daytime radiative cooling and solar heating technologies to continuously power charging-free thermally regenerative electrochemical cycle (TREC) devices, turning ubiquitous low-grade ambient heat into electricity. Notably, by harnessing a substantial 35 °C temperature differential solely through passive cooling and heating effects, the integrated system exhibits a cell voltage of 50 mV and a specific capacity exceeding 20 mAh g -1 of PB. This work unlocks the potential of readily available low-grade ambient heat for sustainable electricity generation.