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

A series of cathode materials of Pr 2-x Sr x NiO 4 (x = 0, 0.3, 0.5, 0.7, 1, 1.5) are synthesized by the EDTA-citric acid route. The results show that the Pr 1.7 Sr 0.3 NiO 4 , Pr 1.5 Sr 0.5 NiO 4 , Pr 1.3 Sr 0.7 NiO 4 and PrSrNiO 4 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 Pr 2-x Sr x NiO 4 . At 800 °C, the electrical conductivity of Pr 1.5 Sr 0.5 NiO 4 and Pr 1.3 Sr 0.7 NiO 4 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 Pr 1.5 Sr 0.5 NiO 4 and Pr 1.3 Sr 0.7 NiO 4 , with ASR values of 0.079 Ω cm 2 and 0.082 Ω cm 2 at 800 °C, respectively. Additionally, the most interesting result is the ASR value obtained after high-temperature thermal decomposition of Pr 2 NiO 4 , where Pr 2 NiO 4 * (decomposed) has the lowest ASR value of only 0.027 Ω cm 2 at 800 °C, showing the best catalytic activity. The maximum power densities of Pr 2-x Sr x NiO 4 (x = 0.5 and 0.7) and Pr 2 NiO 4 * 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 Pr 2-x Sr x NiO 4 cathode material can be effectively improved, but its catalytic performance is partially sacrificed.