The use of conventional fillers often leads to the dilemma of low operating temperature (unfavorable for the output power of the thermoelectric device) or high welding temperature (unfavorable for the thermal stability of the thermoelectric material). In other words, the lack of non-destructive connection technology has hindered the development of medium- and high-temperature thermoelectric devices (especially those incorporating temperature-sensitive and phase-change materials).
Fe-Sb and SnTe have been selected as connection materials to match the thermal expansion of PbTe, and negligible electrical contact resistivity (ρc) and the difference in the coefficient of thermal expansion (∆CTE) have been realized (Figure 2).
A record high energy conversion efficiency of ~11% in a single-stage PbTe module at a temperature difference of 550 K has been realized, and the performance is higher than that of previous reports. More importantly, this low-temperature sintering technology has also been applied to the fabrication of low-temperature Bi2Te3-based and high-temperature half-Heusler-based modules. Due to the advantages of this technique, the module preparation process can be greatly simplified, a wide service temperature range (from room temperature up to 1233 K) can be realized, and the impact of welding thermal cycles (to further improve module efficiency) can be minimized. This technology can effectively overcome the major obstacle in the preparation of thermoelectric modules, and is suitable for almost all thermoelectric materials (Figure 3).
This work titled “Low-temperature sintering of Ag nanoparticles for high-performance thermoelectric module design” was published in the latest volume of Nature Energy (https://www.nature.com/articles/s41560-023-01245-4).