Nanostructure Engineering and Performance Enhancement in Fe2O3-Dispersed Cu12Sb4S13Thermoelectric Composites with Earth-Abundant Elements

Nanostructuring and defect engineering are increasingly employed as processing strategies for thermoelectric performance enhancement, and special attention has been paid to nanostructured interfaces and dislocations that can effectively scatter low- and mid-frequency phonons. This work demonstrated that their combination was realized in Fe2O3-dispersed tetrahedrite (Cu12Sb4S13) nanocomposites, leading to significantly reduced thermal conductivities around 0.9 W m–1K–1at all temperatures and hence a high ZTvalue of ∼1.0, which increases by ∼33% compared with that of the matrix. The plausible enhancement mechanisms have been analyzed with an emphasis on the incorporation of magnetic γ-Fe2O3nanoparticles (NPs) into Cu11.5Ni0.5Sb4S13, leading to various nanostructures (NPs, nanoprecipitates, and nanotwins) and dislocations. A calculated efficiency of ∼9.3% and an average ZTof 0.63 also reveal the potential application of tetrahedrite at medium temperatures. Additionally, the mechanical properties are improved because of a second phase strengthening and nanotwin structures.