Enhanced high-temperature thermoelectric performance of Yb4Sb3 via Ce/Bi double doping and metallic contact deposition for device integration

Thermoelectric (TE) for very high temperatures (> 800 K) have numerous poten- tial applications in the heavy industry and the space exploration. This article focus on the compound Yb4Sb3 which is a promising p-type counterpart to the structurally related and high-performance n-type RE3Te4 (RE = Nb, La, Pr) for the fabrication of high temperature TE modules. A quick and ecient method for synthesizing pure and fully-dense Yb4Sb3 samples was developed and optimized using high-energy ball milling followed by reactive spark plasma sintering. The technique was utilized to produce a new series of doubly doped CexYb4−xBi0.2Sb2.8 compounds. X-ray diraction and scan- ning electron microscopy (SEM) were employed to establish the solubility limit of Ce, which was determined to be x = 0.4. TE properties for Yb4Sb3 and Ce0.4Yb3.6Bi0.2Sb2.8 were measured up to 1273 K, revealing that the doping strategy was eective in reduc- ing the charge carrier concentration and thermal conductivity. This led to a signicant increase in the TE gure-of-merit ZT from 0.2 to 0.4 at 1273 K. This study eventually conducted a preliminary examination of the realization of metallic contacts on Yb4Sb3 through SPS. The results showed that two robust TE legs with Ni and Cu contacts were successfully produced, and SEM analyses was used to study the diusion that occurred at the interfaces. The measured electric contact resistances were very promising, with average values of 2 and 1 μΩ cm2 for Ni and Cu contacts, respectively.