Beijing Tsinghua Changgung Hospital, March 24–In practical energy utilization, a large amount of dispersed low-grade heat has long been difficult to recover effectively, while resources such as water vapor generated during heat exchange are often underutilized. Achieving the synergistic conversion of heat energy and water resources under complex interface conditions remains an important challenge in current energy harvesting research.

Recently, a team led by Zhou Li, director of the Vita Tech Innovation Center at Beijing Tsinghua Changgung Hospital, Tsinghua University, in collaboration with the University of Chinese Academy of Sciences and the Beijing Institute of Nanoenergy and Nanosystems, proposed a self-propelled power generation strategy based on the metastable Leidenfrost effect, starting from the fundamental mechanism of interfacial energy conversion. This work provides a new approach for the synergistic utilization of distributed low-grade thermal energy and water vapor. In this direction, the research team investigated the dynamic control of the solid-liquid-gas triple-phase interface, explored the motion behavior and energy output characteristics of droplets on the interface, and developed a novel device integrating autonomous motion and power generation.

Figure 1. The self-propelled generator based on the metastable Leidenfrost effect

The key to this work lies in the reuse and manipulation of the interfacial barriers associated with the traditional Leidenfrost phenomenon. The research team constructed a dynamically stable solid-liquid-gas triple-phase contact state using interface engineering methods, coupling dynamic asymmetric electric double-layer generation with an aqueous primary battery reaction, enabling microdroplets to continuously generate electrical signals during their movement. Experimental results show that a 30-microliter droplet is needed to continuously generate over 100 pulsed direct current signals, demonstrating strong potential for interfacial energy conversion. Building on this, the team further designed a biomimetic fog-collecting device and integrated it with a self-propelled power generation system, constructing a closed-loop pathway of "water vapor collection—droplet power generation—recycling." This research not only provides a new technical solution for distributed thermal energy recovery but also highlights the potential for synergistic operation of multiple microscale energy conversion mechanisms, supporting the miniaturization and integration design of related devices.

Figure 2. Motion of a self-propelled droplet

Notably, although this research focuses on energy harvesting, the underlying interfacial mass transfer, phase transition regulation, and microscale power generation mechanisms share methodological commonalities with the long-standing focus in the medical-engineering interdisciplinary field of powering medical electronic devices. With the rapid development of wearable monitoring and long-term health management devices, designing lighter and more flexible power supply solutions for small devices has become increasingly important in health technology research and development. This research provides a novel approach to related directions from the perspective of fundamental mechanisms and reflects continuous exploration in the integration of medicine and engineering and cutting-edge interdisciplinary innovation.

The research, titled "Self-Propelled Generator for Low-Grade Heat Harvesting via Metastable Leidenfrost Effect" has been published online in Joule (Cell Press, IF 35.4), a leading international journal in energy research. Beijing Tsinghua Changgung Hospital is the first corresponding author's institution. Zhou Li and Yang Zou (associate researcher at the Vita Tech Innovation Center) are the corresponding authors, Peng Cheng (PhD candidate at the Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences) is the first author. This work was supported by the National Natural Science Foundation of China, the National Key Research and Development Program of China, and the Beijing Natural Science Foundation.

Original link: https://www.cell.com/joule/abstract/S2542-4351(26)00004-8