Microstructure and polarization of La _0.8Sr _0.2MnO ₃ cathode deposited by alcohol solution precursor plasma spraying

Alcohol solution precursor plasma spraying (SPPS) was employed to prepare porous La _0.8Sr _0.2MnO ₃ (LSM) cathode for solid oxide fuel cells (SOFCs). The surface morphology and microstructure of the LSM deposits were characterized by SEM. The electrochemical behavior was investigated through the impedance spectroscopy. The effect of annealing treatment on alcohol SPPS LSM microstructure and cathode polarization was examined. The results show that when the alcohol was used as solvent, at a spray distance of 60 mm, the as-sprayed LSM deposits presented porous agglomerates with a size range from 10 to 60 μm which were mainly composed of small particles ranging from 0.2 to 2 μm. The LSM cathode showed a finely porous microstructure with grain sizes from micrometers to sub-micrometers, Annealing at 1050°C for 2 h in air resulted in coherent porous films of the perovskite phase with a fine microstructure. The electrochemical impedance measurement yielded the cathode polarization of 1.04 and 0.15 Ω·cm ² for the ethanol SPPS LSM at 850°C and 1000°C, respectively.