Dense La0.3Sr0.7TiO3 interconnect sintered in air atmosphere at a reduced temperature with improved conductivity for solid oxide electrochemical cells

La-doped SrTiO 3 (La x Sr 1−x TiO 3 , LST), as the promising ceramic-based interconnect material, usually needs to be sintered in reductive atmosphere at a temperature ≥ 1450 °C, such sintering condition is not friendly to cell fabrication and application. To reduce the sintering temperature of air-sintered LST, seven sintering additives, Bi 2 O 3 , Fe 2 O 3 , Li 2 O, MnO 2 , NiO, V 2 O 5 , and Co 3 O 4 , are added to the LST in this work. The results show that only Co 3 O 4 is conductive to remarkable sintering at the temperatures of 1250 °C. The relative density of LST-3%Co 3 O 4 reaches 92%, while that of the pure LST is only 48%. Moreover, the conductivity of LST-3%Co 3 O 4 achieves 8.2 S/cm at 800 °C in humidified hydrogen, which exceed 5.5 times that of the pure LST. Interestingly, LST-3%Co 3 O 4 exhibits an average TEC of 11.5 × 10 −6 K −1 between 400 and 900 °C, which is very close to that of other components of SOCs .