Eff ects of Ni Doping on Electrical and Thermal Transport Properti es of PrBa2Cu3O7-y Ceramic

Thermoelectric materials have attracted significant attention recently due to their potential to convert waste heat into usable electrical energy. This study focused on investigating a defect perovskite layerstructured PrBa2Cu3O7-y (PrBCO) compound as a viable material for thermoelectric applications. To improve the thermoelectric properties of PrBCO, Ni was substitutionally doped at the Cu site. The samples of PrBa2(Cu1-xNix)3O7-y (x = 0.00, 0.05, 0.10, 0.15, and 0.20) were prepared by sintering at 920˚C for 12 hours in a normal air atmosphere. X-ray diffraction patterns indicated that a second phase appeared when Ni concentration was equal to or higher than 0.10 mol fraction. Scanning electron microscope (SEM) images indicated that the grain size slightly decreased with increasing Ni concentrati on. X-ray absorption spectroscopy (XAS) analysis showed that the local structures of Ni, Cu, and Pr were unchanged, with oxidation states of Pr, Cu, and Ni being higher than +3, between +2 and +3, and +4 , respectively. The study determined that Ni doping in PrBCO at a concentration of x = 0.10 signifi cantly improved the thermoelectric properties, achieving the highest figure of merit with a ZT value of 0.015 at 773 K.