Effects of strontium doping on the structure, oxygen nonstoichiometry and electrochemical performance of Pr2−xSrxNi0.6Cu0.4O4+δ (0.1 ≤ x ≤ 0.5) cathode materials

Pr2−xSrxNi0.6Cu0.4O4+δ (PSNCO, x = 0.1, 0.3, 0.5) oxides with K2NiF4-type structure are synthesized by a glycine-nitrate process as potential cathode materials for intermediate temperature solid oxide fuel cells (IT-SOFCs). The influence of strontium substitution on the structure, oxygen nonstoichiometry, electrical property and electrochemical performance is investigated. Iodometric titration method is employed to study the oxygen nonstoichiometry and the formal valence of nickel. The maximum electrical conductivity reaches 109 S cm−1 at 450 °C in air for Pr1.7Sr0.3Ni0.6Cu0.4O4+δ material. Area specific resistance (ASR) values of all compositions are below 0.11 Ω cm2 at 800 °C, and the Pr1.7Sr0.3Ni0.6Cu0.4O4+δ composition has the lowest ASR value of 0.063 Ω cm2 at 800 °C. Open circuit voltage (OCV) and maximum power density of the single cell (NiO-SDC/SDC/PSNCO) are 0.767 V and 353 mW cm−2 at 800 °C, respectively. The preliminary results indicate that Pr2−xSrxNi0.6Cu0.4O4+δ materials could be good candidates for IT-SOFCs cathode materials.