Effect of microstructures on electrochemical behavior of La_0.8Sr_0.2MnO₃ deposited by suspension plasma spraying

Suspension plasma spraying (SPS) was employed to prepare La_0.8Sr_0.2MnO₃ (LSM) cathode for solid oxide fuel cell (SOFC). LSM powder in the nanometer size range synthesized by the glycine-nitrate processing (GNP) was used as precursor. The surface morphology and microstructure of the LSM deposits were characterized by scanning electron microscopy and x-ray diffraction. The influence of spray distance on SPS LSM microstructure was examined. The electrochemical behavior was analyzed through the impedance spectroscopy. The fine starting particles resulted in a fine microstructure of SPS LSM deposit. The results showed that the microstructure of SPS LSM cathode exhibits significant influence on the cathode polarization. The improved melting degree of LSM particles during spray deposition leads to reduction of the cathode polarization. The specific surface resistance of 0.45 Ω cm² was obtained at 950 °C for SPS LSM cathode deposited at a spraying distance of 70 mm.