Decoupling the Seebeck Coefficient and the Electrical Conductivity in P‐Type SnTe‐Based Thermoelectric Materials by Electroless Cu Plating

Electrical conductivity and the Seebeck coefficient are generally interrelated, making it challenging to decouple them. In this study, P‐type SnTe powders serve as the substrate for the electroless plating of Cu, which is then combined with hot‐press sintering to produce Cu/SnTe materials. As the content of Cu increases, the electrical conductivity rises. In contrast, the Seebeck coefficient remains unvarying. This phenomenon is ascribed to the formation of grain boundary complexions on the grain boundaries of SnTe resulting from the introduction of Cu. Moreover, these grain boundary complexes are capable of reducing the lattice thermal conductivity. Ultimately, under the diverse influences of grain boundary complexes, when the content of introduced Cu is 0.4 wt%, the ZT value of the material attains ≈0.6 at 856 K, which is 150% of that of the SnTe without electroless plating.