Interfacial advances yielding high efficiencies for thermoelectric devices

Abstract

The development of thermoelectric (TE) applications is promising due to great advances achieved in recent decades; however, some limitations still exist in the implementation of TE power generation due to its inferior conversion efficiency (η) compared with that of its competitors. Significantly, its low value is attributed to systematic issues, such as the TE performance of materials, electrode selection, and manufacturing process, resulting in a great challenge for its further enhancement. In this review, three different interfacial issues of TE devices are systematically investigated, and it is demonstrated that the related improvements will be beneficial for increasing their η values. Firstly, the mechanism and controlling approaches focusing on modifying the internal interface of materials remain significant for improving their figure of merit, ZT. Secondly, effective connections between TE elements and electrodes are a prerequisite, and matching optimal contact materials can provide a compatible interface with good stability, low contact electrical and thermal resistance. In addition, considering the long-term stable operation of devices, it is particularly critical to prevent the sublimation and oxidation of TE elements. These unique advances combined with the corresponding strategies demonstrate the potential of TE devices for large-scale power generation applications.