A Review on Flexible Thermoelectric Technology: Material, Device, and Applications

Due to the flexibility and lightness, flexible thermoelectric (TE) technology shows great potential in the field of renewable energy and low-temperature waste heat collection. In recent years, a lot of efforts have been made to improve the efficiency of flexible TE technology, such as synthesizing high-performance flexible TE materials, improving the structure of flexible thermoelectric generators (TEGs), and optimizing the system integration design. This review comprehensively summarizes the flexible TE materials, device types, substrate selection, and fabrication techniques, aiming to reveal the latest research trend of flexible TE technology. The methods used to improve the physical properties of flexible TE materials and device design are discussed, including theoretical analysis, experimental verification, numerical simulation, and especially the potential and challenges of machine learning in flexible TE materials and devices. Besides, we summarized the applications of flexible TE technology in wearable devices, waste heat utilization of industrial heat pipes, medical sensors, Internet of Things, etc. Finally, the current research status of flexible TE technology and the prospect of the potential development of the flexible TE field are discussed.