Impact of Zn doping on the structural properties and thermoelectric performance of CuCr0.85Mg(0.15-x)ZnxO2 (x ≤ 0.05) delafossite materials

In this study, we successfully synthesized a series of CuCr0.85Mg(0.15-x)ZnxO2 (x = 0.00 - 0.05) delafossite materials with different Zn concentrations and investigated their thermoelectric properties. Delafossite materials are promising for thermoelectric applications due to their low thermal conductivity and high Seebeck coefficient. We observed that Zn doping significantly affects the structural properties and thermal conductivity of delafossite materials. Zn atoms can substitute for Cr and Cu atoms in the delafossite structure, leading to carrier concentration and mobility changes. We found that the optimal Zn concentration for enhancing the thermoelectric performance is x = 0.0125 - 0.025, which reduces the thermal conductivity from 5.6 to 4.7 W/mK without significantly compromising the electrical conductivity, improving the fi g ure of merit (ZT). The enhancement of ZT at x = 0.0125 is attributed to a high power factor of 220 mu W/mK(2) resulting from an electrical conductivity of 14.5 S/cm and a Seebeck coefficient of 390 mu V/K. This indicates that Zn doping can effectively scatter phonons and improve the ZT of the delafossite materials.