摘要
A perovskite La 1−x Sr x MnO 3 cathode thin film for an oxygen ion conducting solid oxide fuel cell was prepared using a low power (8.8 kW) liquid solution plasma spray method. Usually, a 30–50 kW Ar plasma torch with temperature higher than all the melting points of solid precursors is essential to synthesis oxides thin film. However, using the liquid precursors as the feeding materials, the required power can be reduced and save a lot of thermal budget. The precursors are water solutions of lanthanum nitrate hexahydrate, manganese(II) nitrate tetrahydrate, and strontium nitrate. The atomic percentage of La in the plasma sprayed La 1−x Sr x MnO 3 cathode film is lower than that of La in the feeding precursor into the torch, which is due to the low boiling temperature of La(NO 3 ) 3 precursor. The oxygen stoichiometry of La 1−x Sr x MnO 3−δ deduced from the valence state of Mn measured by X-ray absorption spectroscopy shows an oxygen deficit structure. The measured low resistivity of 0.07–0.09 Ωcm at room temperature for this La 1−x Sr x MnO 3−δ is essential for oxygen ion transport in the cathode thin film of a solid-state fuel cell.