Improved thermoelectric performance from CrSi₂ by Cu substitution into Si sites

Abstract

We report herein the results of investigations into the thermoelectric properties of Cr(Si1−xCux)2. In the Cu-content range x ≤ 0.04, single-phase Cr(Si1−xCux)2 solid solution is obtained by arc melting and spark plasma sintering. With increasing Cu content, the electrical conductivity increases and the Seebeck coefficient decreases. Hall measurements confirm that the carrier concentration increases and the mobility decreases upon substituting Cu into Si sites. Cu substitution causes a significant decrease in the lattice thermal conductivity of CrSi2 and enhances the maximum dimensionless figure of merit from zT = 0.16 at 600 K for x = 0 to zT = 0.23 at 900 K for x = 0.03. In addition, the temperature at which zT peaks increases from 600 to 900 K with increasing Cu content, which means that the operating temperature can be set by simply adjusting the Cu content.

Improvement of Thermoelectric Properties via Texturation Using a Magnetic Slip Casting Process–The Illustrative Case of CrSi2

“…TMS are characterized by high power factors PF = α 2 /ρ, but their maximum ZT values remain moderate (0.13 for CrSi 2 , 0.20 for doped β-FeSi 2 , and 0.45 for MnSi 1.74 ) due to high thermal conductivities . For these reasons, the majority of published works related to TMS focused on reducing κ using common strategies such as alloying, − nanostructuration, , thin films, and composite synthesis. − Employing these strategies, enhanced maximum ZT ≈ 1 (+150%) for Re-doped MnSi 1.74 , or ZT = 0.25 (+ 70%) for Ge-doped CrSi 2 were achieved, for instance. However, these promising results were often obtained at the expense of increased cost or reduced thermal stability.…”