Hierarchically nanoporous La1.7Ca0.3CuO4−δ and La1.7Ca0.3NixCu1−xO4−δ (0.25 ≤ x ≤ 0.75) as potential cathode materials for IT-SOFCs†
Hierarchically nanoporous materials based on layered perovskite oxides La1.7Ca0.3NixCu1−xO4−δ (x = 0, 0.25, 0.50 or 0.75) have been synthesized by a facile citrate-modified evaporation-induced self-assembly (EISA) method. These La1.7Ca0.3NixCu1−xO4−δ oxides have been evaluated as potential cathodes for intermediate-temperature solid oxide fuel cells (IT-SOFCs) with Ni–YSZ cermet supported type cells. It was found that La1.7Ca0.3CuO4−δ cathode exhibits the maximum power density at high temperature (e.g., 1.5 W cm−2 at 850 °C), while La1.7Ca0.3Ni0.75Cu0.25O4−δ cathode shows the highest power density at intermediate temperature (e.g. 0.71 W cm−2 at 750 °C) using humidified H2 and air as the fuel and oxidant, respectively. The electrochemical performance of single cells with La1.7Ca0.3Ni0.75Cu0.25O4−δ cathode materials with different morphologies demonstrated better performance in the intermediate temperature range when using the cathode prepared by the citrate-modified EISA method, which has a bigger grain size, but with higher surface area and pore volumes.