Harnessing low-grade thermal energy via thermally regenerative electrochemical cycle: critical insights, performance optimization strategies, and cross-domain applications

Low-grade thermal energy is widely distributed with substantial reserves, yet current research technologies fail to fully utilize it, resulting in significant annual energy waste. To recover low-grade thermal energy, the Organic Rankine Cycle (ORC) and thermoelectric materials (TE) have emerged. However, their conversion efficiency under low-temperature conditions falls far short of expectations, making the development of a new low-temperature, high-efficiency recovery technology imperative. Thermally Regenerative Electrochemical Cycles (TREC) have garnered significant attention due to their high efficiency, low cost, and stability at low temperatures. Although substantial progress has been made in TREC development, core challenges persist. Current TREC research exhibits a fragmented approach, with diverse studies focusing on various parameters and influencing factors. This fragmented research pace lacks systematic organization, obscuring the future trajectory of TREC development—particularly the connection between micro-level parameters affecting performance and macro-level components. To address the disconnect between research focus and current bottlenecks, this work systematically summarizes the latest research advances in TREC technology, delving progressively deeper along core parameters such as temperature coefficient, specific heat, and capacity. It connects the micro-level performance manifestations with macro-level performance characteristics. Furthermore, this paper proactively explores future development directions for TREC. The issue of heat recovery, which has received insufficient attention, has been reemphasized and has added new insights to this issue based on the research of previous scholars.