Synthesis and properties of Sr doped Pr2NiO4 cathode material for intermediate temperature solid oxide fuel cells

Abstract

A series of cathode materials of Pr2-xSrxNiO4 (x = 0, 0.3, 0.5, 0.7, 1, 1.5) are synthesized by the EDTA-citric acid route. The results show that the Pr1.7Sr0.3NiO4, Pr1.5Sr0.5NiO4, Pr1.3Sr0.7NiO4 and PrSrNiO4 exhibit excellent structural stability and carbon dioxide resistance, and also exhibit good chemical compatibility and thermal matching with the SDC electrolyte. It is also found that the Sr doping is beneficial in improving the high temperature conductivity of Pr2-xSrxNiO4. At 800 °C, the electrical conductivity of Pr1.5Sr0.5NiO4 and Pr1.3Sr0.7NiO4 reaches 185 S cm−1 and 317 S cm−1, respectively. In addition, the area-specific resistance (ASR) value increases significantly with Sr doping, which reduces the catalytic activity of the material. Acceptable ASR values are obtained for Pr1.5Sr0.5NiO4 and Pr1.3Sr0.7NiO4, with ASR values of 0.079 Ω cm2 and 0.082 Ω cm2 at 800 °C, respectively. Additionally, the most interesting result is the ASR value obtained after high-temperature thermal decomposition of Pr2NiO4, where Pr2NiO4* (decomposed) has the lowest ASR value of only 0.027 Ω cm2 at 800 °C, showing the best catalytic activity. The maximum power densities of Pr2-xSrxNiO4 (x = 0.5 and 0.7) and Pr2NiO4* are found to be 515, 430, and 548 mW cm−2 at 800 °C, respectively. These results show that when the Sr doping amount is less than 1.5, the stability of the Pr2-xSrxNiO4 cathode material can be effectively improved, but its catalytic performance is partially sacrificed.