AbstractWe demonstrate that the thermoelectric properties of p-type chalcogenides can be effectively improved by band convergence and hierarchical structure based on a high-entropy-stabilized matrix. The band convergence is due to the decreased light and heavy band energy offsets by alloying Cd for an enhanced Seebeck coefficient and electric transport property. Moreover, the hierarchical structure manipulated by entropy engineering introduces all-scale scattering sources for heat-carrying phonons resulting in a very low lattice thermal conductivity. Consequently, a peak zT of 2.0 at 900 K for p-type chalcogenides and a high experimental conversion efficiency of 12% at ΔT = 506 K for the fabricated segmented modules are achieved. This work provides an entropy strategy to form all-scale hierarchical structures employing high-entropy-stabilized matrix. This work will promote real applications of low-cost thermoelectric materials.
Thermoelectric behaviour with high lattice thermal conductivity of Nickel base Ni2CuCrFeAlx (x = 0.5, 1.0, 1.5 and 2.5) high entropy alloys
