Thermoelectric properties of a doped LaNiO₃ perovskite system prepared using a spark-plasma sintering process

Both perovskites LaNiO₃ and LaCuO₃ have a limitation associated with phase transitions for high-temperature thermoelectric applications. The optimized conditions were investigated to obtain the LaNi_1-xCu_xO_3-δ perovskite single phase showing a Cu-doping effect into Ni sites against unintended deoxidized phases. Three advantages of synergetic effects due to the simultaneous presence of nickel and copper were investigated: a low melting temperature of CuO as compared to that of NiO, the absence of intermediated deoxidized phases in the LaCuO₃ system, and the Cu doping effect, which suppresses the formation of intermediate secondary phases. A solid solution was also fabricated using a spark-plasma sintering (SPS) process for the purpose of sintering LaNi_1-xCu_xO_3-δ compositions at a low sintering temperature.