Self‐Maintained Thermal Charging Cells for the Efficient Harvesting of Waste Heat at Elevated Temperatures

Thermal charging cells face two main challenges that limit their practical applications. 1) Still lacking the systems suitable for operation under higher temperature environments, even though high‐temperature waste heat recovery systems have greater application potential and practical significance compared with room‐temperature systems. 2) There are limitations in the self‐sustaining performance of continuous discharge under temperature differences, which hold critical significance for the real‐world implementation of thermal charging cells. This study has successfully constructed a high‐temperature resistant thermal charging cells system that can operate at 160 °C by optimizing the design of electrode solutions and layered electrode materials, which is currently the highest temperature achieved as far as we know. This high‐temperature resistant thermal charging cells system can achieve a considerable thermal voltage of 960 mV and an impressive Carnot‐relative efficiency of 14%, outperforming the state‐of‐the‐art thermoelectric systems. This work has investigated the self‐maintained capability of the thermal charging cells system under the opposing effects of ionic concentration and temperature differences between the electrodes and experimentally verified this performance by adjusting the lithium‐ion concentration and temperature difference. Furthermore, the stability of the system under long‐term charge and discharge cycles was tested, making it the longest running system currently. This work significantly highlighted the broad application prospects of thermal charging cells systems in practical implementations, particularly in advanced thermal energy harvesting and conversion technologies.